Browse Topic: Battery thermal management

Items (169)
Find
018 - Simulation of Advanced Regenerative Braking Strategies in a Series Plug-in Hybrid Electric VehicleSAE-PP-001411/23/2021
Regenerative braking is an important factor in improving hybrid electric vehicle efficiency. This paper proposes a new regenerative braking strategy that activates preemptively during a distracted driving scenario, before service brakes are utilized. The strategy uses onboard advanced driver assistance systems, such as forward facing radar, to detect when an object is approaching fast enough to enable regenerative braking in response. The proposed strategy is simulated on a full-vehicle model of a series plug-in hybrid electric vehicle. A driver model is developed to mimic the behavior of a distracted driver through delayed response time to the changing speed of a lead vehicle. Multiple trials are simulated using different combinations of existing regenerative braking strategies along with the proposed strategy. Results show that a preventative regenerative braking control strategy can recuperate significant amounts of energy while also improving vehicle safety. Coupling the proposed strategy with an existing brake pedal regeneration strategy returns energy recuperation results that are higher than a system consisting of brake pedal regeneration coupled with coast regeneration.
Mutagaana, Festo
Battery Management Systems for Rechargeable Lithium Batteries Used in Aerospace StandardsAIR6897 (Current)8/20/2020
This AIR provides basic background information and guidance for design and development of BMS architectures to be used in RLBs for aerospace applications. This guidance applies to batteries that are considered “installed” equipment and are intended to be part of the original or supplemental type certification or military airframe qualification.
AE-7D Aircraft Energy Storage and Charging Committee
Adhesives, Sealants, and Heat Transfer Materials in Battery Systems: A Primer on Materials, Applications, and End-Use Performance RequirementsJ3178_202005 (Current)5/5/2020
This SAE Information Report introduces key concepts and properties of adhesives, sealants, and HTMs and the roles they serve in present-day battery systems applications. The basic chemistry and properties of the three types of materials are summarized along with important health and environmental information. Relevant material dispense methodologies and equipment for material dispensing is reviewed. A series of representative battery applications examples employing adhesives, sealants, and HTMs is also provided with particular attention given to end-use performance.
Battery Systems Adhesives, Sealants and Heat Transfer Matl's
An Electric Motor Thermal Bus Cooling System for Vehicle Propulsion - Design and Test2020-01-07454/14/2020
Automotive and truck manufacturers are introducing electric propulsion systems into their ground vehicles to reduce fossil fuel consumption and harmful tailpipe emissions. The mobility shift to electric motors requires a compact thermal management system that can accommodate heat dissipation demands with minimum energy consumption in a confined space. An innovative cooling system design, emphasizing passive cooling methods coupled with a small liquid system, using a thermal bus architecture has been explored. The laboratory experiment features an emulated electric motor interfaced to a thermal cradle and multiple heat rejection pathways to evaluate the transfer of generated heat to the ambient surroundings. The thermal response of passive (e.g., carbon fiber, high thermal conductivity material, thermosyphon) and active cooling systems are investigated for two operating scenarios. The test results demonstrate that up to 93% improvement can be achieved in cooling system energy consumption during a light load electric motor condition while maintaining a target core temperature of 70°C. The governing thermal system dynamics will be reviewed in discussion of the experimental observations.
Shoai Naini, Shervin, Miller, Richard, Wagner, John, Rizzo, Denise, Sebeck, Katherine
Thermal Analysis of a Magnetic Contactor in Electric Vehicle Li-Ion Battery Packs2020-01-13454/14/2020
In this paper, we perform 3D numerical simulations to understand the thermal operation of a high-current-load DC Magnetic Contactor (MC) within a Li-ion battery pack. The main focus is on evaluating the thermal behavior of an electronically controlled MC through a parametric study that investigates the effect of the magnitude of electric current with the corresponding Ohmic heat generation of the MC. For the numerical analysis we perform time-accurate, conjugate heat transfer-based 3D CFD simulations on high spatial resolution grids with commercial CFD software STAR-CCM+. The results of the numerical simulations with temperature dependent material properties are validated against experimental temperature measurements at various locations on the outer body of the MC. The spatial distribution of temperature, and current within the MC and its connected components are also computed for various input parameter values to evaluate a range of its operational validity within an automotive Li-ion battery pack.
Pulugundla, Gautam, Galvan, Karlo, Dubey, Prahit
The Effect of Driver's Behavior and Environmental Conditions on Thermal Management of Electric Vehicles2020-01-13824/14/2020
Worldwide projections anticipate a fast-growing market share of the battery electric vehicles (BEVs) to meet stringent emissions regulations for global warming and climate change. One of the new challenges of BEVs is the effective and efficient thermal management of the BEV to minimize parasitic power consumption and to maximize driving range. Typically, the total efficiency of BEVs depends on the performance and power consumption of the thermal management system, which is highly affected by several factors, including driving environments (ambient temperature and traffic conditions) and driver's behavior (aggressiveness). Therefore, this paper investigates the influence of these factors on energy consumption by using a comprehensive BEV simulation integrated with a thermal management system model. The vehicle model was validated with experimental data, and a simulation study is performed by using the vehicle model over various traffic scenarios generated from a traffic simulator. Particularly, the aggressiveness of a human driver is emulated by varying parameters in the intelligent driver model.
Kim, Jaewoong, Rodriguez, Rodolfo, Kwak, Kyoung Hyun, Jung, Dewey, Kim, Youngki
Sensorless Individual Cell Temperature Measurement by Means of Impedance Spectroscopy Using Standard Battery Management Systems of Electric Vehicles2020-01-08634/14/2020
Lithium ion technology is state of the art for actual hybrid and electrical vehicles. It is well known that lithium ion performance and safety characteristics strongly depend on temperature. Thus, reliable temperature measurement and control concepts for lithium ion cells are mandatory for applications in electrical cars. Temperature sensors for all individual cells increase the battery complexity and cost of a battery management system. Normally, temperature is measured on module level in current battery packs, without observation of the individual cell temperature. Sensorless cell impedance-based temperature measurement concepts have been published and are validated in laboratory studies. Dedicated test equipment is usually applied, which is not useful for automotive series application. This work describes a practical approach to enable impedance-based sensorless internal temperature measurement for all individual cells using state-of-the art battery management system components. Excitation is generated by DC to DC converters of a standard commercial active balancing systems. For data acquisition, also an established commercial battery monitoring circuit unit is used. To overcome bandwidth limitations, a sub-sampling scheme is presented, which allows to determine the impedance at higher frequencies than the sampling rate. Impedance calculation is performed by means of efficient digital signal processing concepts with low demand on memory and processing power. Thus, the method can be integrated into existing battery management systems with low implementation effort. The concept is demonstrated on a 4-cell submodule of 26 Ah automotive Li-ion cells. It can also be applied in low-cost battery management systems without active balancing capability.
Haussmann, Peter, Melbert, Joachim
Iterative Dynamic Programming Based Model Predictive Control of Energy Efficient Cruising for Electric Vehicle with Terrain Preview2020-01-01324/14/2020
As a global optimization method, dynamic programming (DP) can be employed to seek the optimal velocity with minimum energy consumption for EV on given driving cycles. Due to its terrible computational burden, conventional DP is not suitable for real-time implementation especially with higher dimensions. In this paper, we propose an iterative dynamic programming (IDP) approach to reduce computing time firstly. The IDP can obtain the optimal control laws alike the conventional DP by converging the optimal control strategy iteratively and save considerable computing time. Second, the developed IDP and model predictive control (MPC) are combined to establish a real-time cruising controller called IDP-MPC for an EV with terrain preview. In the predictive controller, we use the IDP to solve a constrained finite horizon nonlinear optimization problem. Finally, to assess the performance of the proposed cruising controller, simulation on a realistic urban expressway road terrain is implemented. Energy-saving potential of the IDP-MPC controller is explored by comparing to DP and constant speed (CS) cruising controllers. The comparative study indicates that the IDP-MPC controller can obtain near-optimal energy-saving capacity compared to DP controller.
Ju, Fei, Zhuang, Weichao, Wang, Liangmo, Wang, Qun
Research on the Performance of Battery Thermal Management System Based on Optimized Arrangement of Flat Plate Heat Pipes2020-01-01624/14/2020
The thermal management system is essential for the safe and long-term operation of the power battery. The temperature difference between the individual cells exceeds the acceleration of the battery performance, which leads to battery out of use and affects the performance of the vehicle. Compared with the low heat transfer coefficient of the air-cooling system, the complex structure of the liquid-cooling system and the large quality of phase change material system, the heat pipe has high thermal conductivity, strong isothermal performance and light weight, it’s an efficient cooling element that can be used for thermal management. In this study, the flat plate heat pipe(FPHP) is used to manage the temperature of the battery, through experiments, the optimized placement of the flat heat pipe is obtained. Based on this, the thermal performance of the thermal management system is studied, thus achieve the purpose of reducing the maximum temperature of the batteries and balancing the temperature difference between batteries. In this paper, a square LiFePO4 battery pack is taken as the object, and the battery heat generation-heat transfer-heat dissipation is the main line. Firstly, the battery heat generation model is established according to the thermal characteristics of the battery, and then based on the heat transfer characteristics of the FPHP, establish the heat transfer model of FPHP. Then the thermal management performance of the battery pack under the conditions with and without FPHP was studied by different discharge magnifications experiments. By comparing with simulation results and the natural cooling results, the superiority of the flat heat pipe at different discharge rates was obtained. Studies have shown that this thermal management system keeps the cell temperature difference within 3 °C. Used in electric vehicles, it provides reference and support for future thermal management of high-power batteries.
Zheng, Xingmang, Tan, Gangfeng, Sun, Meng, Zhou, Fangyu, Liu, ZhiQiang
Enhancement of Heat Exchanger Performance Using Oscillating Flow2020-01-09434/14/2020
In this research work, the heat transfer enhancement by using oscillatory flow of the thermal fluid between cold and hot reservoir has been analyzed both theoretically and using simulation methods. The main objective of this study is to examine the feasibility of a system working under oscillatory flow conditions compared to its steady flow counterpart. The principle of incrementing thermal diffusion over molecular diffusion by establishing oscillatory flow has been utilized in this case. The system has been designed and the effect of the flow condition has been analyzed using ANSYS Fluent k-epsilon model. The effect of change in the magnitude and frequency of oscillation on local Nusselt number has been computed. The observed increment in the Nusselt number by increasing the amplitude and frequency of the fluid has been bolstered by analytical calculation. A comparison in the heat transfer of a system working under oscillating and a steady flow conditions has been generated to establish the need for oscillating flow. The scope of the study has been extended to explore possibility of implementation of this concept in the automotive HVAC system and in the cooling, mechanisms employed in microelectronic components present onboard e-vehicles.
Rajagopalan, Haripriya, Premchandra Tavorath, Adhithiya, Pol, Sakshi, Dhamangaonkar, Pradyumna, Rajagopalan, Haripriya, Premchandra Tavorath, Adhithiya, Pol, Sakshi, Dhamangaonkar, Pradyumna
Simulation and Parametric Analysis of Battery Thermal Management System Using Phase Change Material2020-01-08664/14/2020
The thermophysical parameters and amount of composite phase change materials (PCMs) have decisive influence on the thermal control effects of thermal management systems (TMSs). At the same time, the various thermophysical parameters of the composite PCM are interrelated. For example, increasing the thermal conductivity is bound to mean a decrease in the latent heat of phase change, so a balance needs to be achieved between these parameters. In this paper, a prismatic LiFePO4 battery cell cooled by composite PCM is comprehensively analyzed by changing the phase change temperature, thermal conductivity and amount of composite PCM. The influence of the composite PCM parameters on the cooling and temperature homogenization effect of the TMS is analyzed. which can give useful guide to the preparation of composite PCMs and design of the heat transfer enhancement methods for TMSs.
Lin, Chunjing, Sun, Yuhan, Li, Zhao, Xu, Sichuan
Powertrain Thermal System Development for Small BEV2020-01-13834/14/2020
The dynamic performance of battery electric vehicles (BEV) is affected by battery output power, which depends on state of charge (SOC) and the temperature of battery cells. The temperature of the batteries varies in particular with the environment, in which the user stores the vehicle, and the battery output power. It is therefore necessary to employ thermal management systems that can control the battery temperature within the optimal range under severely hot and cold conditions in BEVs. A highly sophisticated thermal management system and its operation strategy were developed to fulfill the above requirements. The powertrain components to be thermo-controlled were located into two coolant circuits having different temperature range. The compact and efficient front-end heat exchangers were designed to optimally balance the cooling performance of powertrain, cabin comfort, vehicle aerodynamics and the vehicle design. The battery pack was optimally thermo-controlled by precisely controlling two 3-way valves in all driving and environmental conditions. To reduce the temperature variation between battery cells, the coolant passage including cooling plates in the battery pack were designed so that the coolant was homogeneously distributed into all battery modules. The pre-conditioning system of the battery, which controlled its temperature before driving by using telematics, were added to the thermal management system. It was clarified that this system significantly enhanced the driving range at low ambient temperature conditions. The developed system including control strategy realized that Honda’s small BEV demonstrated high dynamic and energy-efficient performance under all environmental conditions.
Ohnuma, Yoshikazu, Yamagishi, Yosuke, Minami, Katsuya
Comprehensive 3D Thermal Modeling of Vehicle-Ready Battery Module2020-01-13854/14/2020
Thermal management of vehicle battery pack is crucial in determining the life/ageing of the battery pack, in establishing the range of the vehicle on a day to day basis and in determining the safety of the vehicle and occupants. An effective design of a thermal management system cannot be established solely through experimentation as it is time consuming and costly. Accurate computational models are required to aid in the design process. This study describes the development and validation of 3D computational model for simulating electrical and thermal characteristics of a vehicle-ready battery module. The modeling process starts with the full 3D CAD geometry of the module including the coolant channels and cold plate. As part of the study, an experimental test case was setup. This included a climate chamber for the initial soak of the module and to control ambient temperature. Coolant was pumped through channels underneath the cold plate atop which the cells sat in blocks. The cell bottom area conducted heat through a thermal interface material and through the cold plate. The effectiveness of cell bottom cooling as opposed to side cooling is demonstrated through this set up. Thermocouples were placed on various locations across the module including three placed vertically on a given cell. A severe constant discharge test of 1.5C and a fast charge test were conducted until the cutoff voltage was reached. The model was run under the same boundary conditions as the test setup. The battery cell electrical characteristics were evaluated to determine the electrical resistance and open circuit voltage of the cell. The cell resistance was derived as a function of both state of charge (SOC) and temperature of cell. The model also simulates the inter cell variation in current magnitude occurring due to the differences in cell temperatures. The thermal interface material (TIM) and the resistance offered by it to heat conduction through the cell bottom was also modeled. The model temperatures correlated to within 4% of experiment measurements on a transient basis. The correlation is demonstrated across all locations on the module and for the coolant.
Velivelli, Aditya, Khaleghi Rahimian, Saeed, Tang, Yifan
Pulsating Heat Pipe Automotive Application2019-36-02271/13/2020
It is proposed a study to evaluate PHP (pulsating heat pipes) device application in battery thermal management systems for HEV (hybrid-electric vehicle) and EV (electric vehicle). Firstly, it is necessary to understanding Li-ion (lithium ion) batteries for HEV/EV, the electrical energy supply state-of-the-art. The analyzed aspects were battery framework and configuration; working principles and mechanisms; and market penetration and potential. Secondly, the adverse effects of temperature over such batteries were discussed. After understanding the case study, a battery modeling survey was performed in order to later evaluate BTMSs (battery thermal management systems). Well comprehended case study and battery modeling, then, it was possible to examine current automotive battery cooling and heating solutions. Finally, PHP was evaluated as a possible BTMS regarding technical and commercial aspects, explaining what would be the requisites in order to attend automobile heat dissipation demands and the challenges for embedding it.
Barbosa de Oliveira, Rafael Beicker, Villalva, Sergio Gradella, Filho, Luiz Paulo Rodrigues, Windlin, Fernando Luiz, Alegre, Guilherme Henrique Mayer, Gonçalves do Santos, Rogério
Effect of Tab Cooling on Large-Format Lithium-Ion Pouch Cells2019-01-226112/19/2019
Battery thermal management systems can extend service life time while operating Lithium-ion batteries in hot and humid climates. To study thermal and electrochemical behaviors of a large format cell for the tab cooling method, this paper presents a Dual Potential Multi-Scale Multi-Domain (MSMD) approach using the equivalent circuit model in ANSYS Fluent software. A pouch cell of 25 Ah consists of N1/3Mn1/3Co1/3O2 (NMC) cathode and graphite anode is used for the model validation. The simulation results present the effect of tab cooling temperature at different discharge rates as well as the effect of the cell surface area and its thickness.
Theinglim, Kanchai, Poramapojana, Poowanart
Innovative Fluid Allowing a New and Efficient Battery Thermal Management2019-01-225912/19/2019
With the increasing availability of fast charging stations across the globe, tighter and tighter constraints are placed on electric vehicles batteries. In order to handle the thermal stresses induced during fast charging, the improvement of the existing battery thermal management systems has become key. This article presents an innovative thermal management system for batteries. The system consists of circulating a newly developed highly advanced dielectric fluid in direct contact with the electrochemical cells of the battery pack. Experiments on our dedicated bench test and numerical simulations are reported here demonstrating the performance of this system with fluids, i.e. its ability to efficiently regulate the temperature of the battery cells even under fast charging conditions and low flow rates. Consequently, this thermal management strategy could be implemented within the next generation of battery electric vehicle (BEV) using conventional pumping systems and lead to an improved battery lifetime and therefore a lower total cost of BEV ownership.
RAISIN, Jonathan, CHAMPAGNE, Nicolas
Experimental Investigation of Electric Vehicle Performance and Energy Consumption on Chassis Dynamometer Using Drive Cycle Analysis13-01-01-000212/2/2019
This article reports an experimental study carried out to investigate the vehicle performance and energy consumption (EC) of an electric vehicle (EV) on three different driving cycles using drive cycle analysis. The driving cycles are the Indian Driving Cycle (IDC), Modified Indian Driving Cycle (MIDC) and Worldwide harmonized Light vehicles Test Cycle (WLTC). A new prototype electric powertrain was developed using an indigenous three-phase induction motor (3PIM), Li-ion battery (LiB) pack, vector motor controller, and newly developed mechanical parts. In this research work, a pollution-causing gasoline car (Maruti Zen) was converted into an EV by using the new powertrain. The EV conversion vehicle was used as the test vehicle. After the removal of the Internal Combustion Engine (ICE) the new powertrain was integrated with the vehicle’s gearbox (GB) system which was configured on a single motor, fixed gear configuration having a gear ratio of 1.28:1. The EV performance tests were carried out on the chassis dynamometer that followed the driving cycles. The maximum speed test showed a top speed of 64 km/h for the EV. The average vehicle speed and EC of the EV were 21.82 km/h and 106.23 Wh/km for the IDC, 17.75 km/h and 110.91 Wh/km for the MIDC-I, and 19.57 km/h and 87.35 Wh/km for the WLTC-low, respectively. The test results of battery current, input power, mechanical power, and EC with respect to the vehicle speed and torque versus motor rpm were analyzed and discussed. It was observed that the performance and EC of the test EV need to be improved. The study and test results verified the new electric powertrain system (EPT) suitable for a city EV and provided useful data for design and performance improvement of the indigenous battery and motor drive system.
Lairenlakpam, Robindro, Kumar, Praveen, Thakre, Gananath Doulat
Numerical Simulation of Battery Thermal Management Systems in Electric Vehicles2019-28-248111/21/2019
Electric vehicle works on stored energy inside the batteries or cells. These units needs to be regulated by cool down or heat up to perform utmost. This temperature regulation also ensure individual battery or cell life. BCS are installed on vehicles to regulate the temperature around battery packs. To ensure maximum performance of these units, numerical simulation is performed and detailed optimization of flow rate as well as flow path into BCS is carried out. All the parts are assembled inside the unit as per defined packaging area or size. Numerical modelling (CFD) is performed to examine the flow path. Flow path is very important to examine, as BCS units consists of condenser. It is very important for condensers to perform efficiently, which means air flow should happen across it appropriately. If sufficient flow is not happening across the condenser, then performance of condensers comes down and optimum temperature around battery packs cannot be maintained. This will affect the performance of battery pack capacity as well as individual battery life. Based on results obtained from existing design modifications are done to develop an optimum design and position of the unit on vehicle is also studied. Securing effective flow rate to attain maximum performance of battery cooling systems. This study mainly focus on flow behavior and flow rate only. For maintaining temperature in optimum range (20°C to 35°C) [1, 2, 3] where BCS plays very important role. This study offers importance of design, like optimizing position of heat exchangers and other openings around the coul. Later condenser inlet air velocity data from CFD is compared with test results. Numerical analysis (CFD) is performed using STAR CCM+ software. Which served as key resource to optimize the overall design as well as position.
Nuthi, Bharat Kumar, S, Vijayaraghavan, Govindaraj, D.
Design and Development of Automotive Battery Management System2019-28-249811/21/2019
Battery operated vehicle needs accurate management system because of its quick changes in State of Charge (SoC) due to aggressive acceleration profiles and regenerative braking. Li-ion battery needs control over its operating area for the safe working. The main objective of the proposed system is to develop a BMS having algorithms to estimate accurate SoC, balance individual cells, thermal management, and provide safe area of operation defined by voltage and temperature. Proposed methodology uses Coulomb Counting as well as Model-based Design approach wherein nonlinear behavior of battery is modeled as Equivalent Circuit Model to compute the SoC and degradation effect on battery to decide the end of life of battery. Also performing Inductive Active Balancing on cells to equalize the charge. The study aims on deploying the model-based system on embedded platform which would help industry to reduce the model development time and focus on development of controlling algorithms for high end users. Active Balancing Architecture proposed here reduces the complexity of algorithm and at the same time decreases the balancing time.
Dange, Dipali, Ballal, Radhika, Murali, Meera, Sonawane, D.N., Prakash, AK
Simulation Study on Driving Range at High and Low Temperature2019-01-507111/4/2019
With the popularity of EVs, driving range has become one of the focuses of people's concern. The anxiety about driving range was particularly evident in winter and summer, because of the use of air conditioning at high temperatures and heating at low temperatures, as well as the power supply capacity of power batteries at different temperatures. At the same time, the energy consumption of thermal management components and the influence of thermal management on the efficiency of other components also need to be considered. The high and low temperature driving range is studied by means of simulation, which has the characteristics of low cost and fast speed. For the vehicles simulated in the article, driving range at 25 °C is 240 km, at -30 °C reduced to 34% (81.9 km), at 40 °C reduced to 73% (176 km). In this paper, the simulation modeling and analysis on the driving range of an EV are carried out. The simulation model includes air conditioning system and crew cabin, power battery system and its cooling system, motor system and its cooling system, driving system and control system, etc. This paper provides a simulation method and research method for studying the performance of EVs at high and low temperature, and provides a theoretical basis and realization form for improving driving range by means of control and parts optimization.
Yu, Jiang, Nie, YanXin, MingJun, Dong, Xie, Ning, Ma, BaoTong, Xu, Zhe
Next Generation HEV Powertrain Design Tools: Roadmap and Challenges2019-01-260210/22/2019
Hybrid electric vehicles (HEVs) represent a fundamental step in the global evolution towards transportation electrification. Nevertheless, they exhibit a remarkably complex design environment with respect to both traditional internal combustion engine vehicles and battery electric vehicles. Innovative and advanced design tools are therefore crucially required to effectively handle the increased complexity of HEV development processes. This paper aims at providing a comprehensive overview of past and current advancements in HEV powertrain design methodologies. Subsequently, major simplifications and limits of current HEV design methodologies are detailed. The final part of this paper defines research challenges that need accomplishment to develop the next generation HEV architecture design tools. These particularly include the application of multi-fidelity modeling approaches, the embedded design of powertrain architecture and on-board control logic and the endorsement of multi-disciplinary optimization procedures. Resolving these issues may indeed remarkably foster the widespread adoption of HEVs in the global vehicle market.
Anselma, Pier Giuseppe, Belingardi, Giovanni
A Coupled Lattice Boltzmann-Finite Volume Method for the Thermal Transient Analysis of an Air-Cooled Li-Ion Battery Module for Electric Vehicles with Porous Media Insert Modeled at REV Scales2019-24-024210/7/2019
Lithium ion batteries are the most promising candidates for electric and hybrid electric vehicles, owe to their ability to store higher electrical energy. As a matter of fact, in automotive applications, these batteries undergo frequent and fast charge and discharge processes, which are associated to internal heat generation, which in turns causes temperature increase. Thermal management is therefore crucial to keep temperature in an appropriate level for safe operation and battery wear prevention. In a recent work authors have already demonstrated the capabilities of a coupled lattice Boltzmann-Finite Volume Method to deal with thermal transient of a three-dimensional air-cooled Li-ion battery at different discharging rates and Reynolds numbers. Here, in order to improve discharge thermal capabilities and reduce temperature levels of the battery itself, a layer of porous medium is placed in contact with the battery so to replace a continuum solid aluminum layer. Many studies, which have already demonstrated how the porous media can improve thermal performance of heat exchange systems, are present in recent literature. There is a large number of models for representing porous media, one can implement porosity effects directly on the resolved equations or precisely modeling the porous medium geometry. In this work, porous medium has been modeled at REV scales including characteristic effects directly on Navier-Stokes and energy equations. The use of a porous insert, rather than of a solid aluminum lamina, should improve capabilities of discharging the same amount of heat generated from the battery. More specifically, aluminum open cell metal foams are considered in this work, due to the large availability of literature data. The analysis will be carried out with varying porosity and pore per inch distribution at different Reynolds number so to highlight benefits which derive from such an insert. Results will be compared in terms of temperature profiles under different working conditions and referring to the original solution equipped with the solid aluminum lamina.
Chiappini, Daniele, Tribioli, Laura, Bella, Gino
A Comparison of Model Order Reduction Techniques for Real-Time Battery Thermal Modelling2019-01-05034/2/2019
Battery temperature is known to have a critical influence on overall battery pack performance, from electrochemical behavior, charge acceptance, power availability, trip efficiency, safety, reliability and life-cycle costs. Temperature monitoring is critical to ensure safe and reliable battery pack operation. Monitoring of cell temperatures in battery packs allows for control and estimation algorithms that can ensure homogenous pack temperature distribution, prevent excessive pack temperature rise and even infer cell core temperature, potentially allowing to both predict and mitigate onset of thermal runaway. The increasing need for improved accuracy requires inclusion of more detail in the modelling stage, leading inevitably to ever larger-scale, ever more complex dynamical systems. Simulations in such large-scale settings lead in turn to unmanageably large demands on computational resources, which is the main motivation for Model Order Reduction. Model Order Reduction is focused on reducing the complexity of large-scale dynamical systems, while preserving their input-output behavior. Reduced models mimic the complex behavior of large-scale dynamical systems, and can be efficiently used for design, optimization and sensitivity analysis. The resulting reduced order model can be used to replace the original system as a component in a larger simulation or it might be used to develop a simpler and faster controller suitable for real time applications. Three model order reduction techniques are compared. The first method, Balanced Truncation, assumes access to the high-fidelity model structure is available whilst the other two, Nyquist and neural network approximation, assume only input/output behavioral knowledge is available. The reduced order models are compared, in simulation, to a high-fidelity model of a battery pack in terms of simulation speed-up, model accuracy and property preservation. The applicability of each technique for real-time applications, particularly in the context of xEV (grid connected electric vehicle) thermal management, together with pros and cons of each method is discussed.
McGahan, Paul, Rouaud, Cedric, Booker, Michael
A Thermal Electric Two-Way Coupled Battery Pack Model for an All Electric VW Motorsport Racer2019-01-05934/2/2019
This paper presents a thermal electric two-way coupled li-ion battery pack model for an all-electric VW motorsport racer. It starts from the hybrid pulse power characterization (HPPC) test data at different state of charge (SoC) and temperature levels. Such information is used for cell level battery equivalent circuit model (ECM) parameter identification. Multiple cell ECMs are connected in series to create a module ECM. Battery thermal performance of the module is simulated first by computational fluid dynamics (CFD) for the module. Then, a thermal reduced order model (ROM) is created out of the CFD solution. The thermal ROM is then two-way coupled with the battery module ECM to form a complete battery module model. Multiple module models are connected to create a battery pack model. The complete pack model is then exported into Simulink for validation and simulation. Such a battery pack model can finish a complete charge or discharge cycle simulation within a few minutes of simulation time.
Hu, Xiao, Kshatriya, Aditya, Wang, Xingshi, Ahrenholz, Benjamin, Folio, Stephane
Time-Accurate CFD Analysis of Liquid Cold Plates for Efficient Thermal Performance of Electric Vehicle Li-Ion Battery Modules2019-01-05004/2/2019
An efficient Thermal Management System (TMS) is crucial for superior performance of an automotive Li-ion Battery Module (BM). Liquid-Cooled TMS, consisting of a coolant flow through a cold plate, offers higher rate of heat transfer compared to passive or forced-air cooled TMS, thus allowing cells to charge/discharge at aggressive rates and higher ambient temperatures while maintaining the cell temperatures within an optimal range. In the current study, we investigate the effect of a variety of cold plate channel sizes and configurations on the overall thermal performance of a liquid-cooled BM using three-dimensional, time-accurate CFD simulations with variable heat load from cylindrical 21700 Li-ion cells. Specifically, we consider 8 different cold plate designs by varying the size and the flow path of the coolant channels. For all the cold plate designs, we evaluate the average and maximum cell temperatures, and heat transfer rate at a module discharge rate of 1C. Additionally, the coolant pressure drop across the entire cold plate is also computed, which helps in providing information about the energy efficiency of the TMS.
Pulugundla, Gautam, Dubey, Prahit, Srouji, A
Life Estimation and Thermal Management of a 48V Mild-Hybrid Battery Pack2019-01-10014/2/2019
The 48V mild-Hybrid system uses a 48V Lithium - Ion battery pack to boost the engine performance, to harness recuperative energy and to supply the accessory boardnet power requirement. Thermal management of the 48V battery pack is critical for its optimal utilization to realize the mild hybrid functionality, to meet CO2 reduction targets and useful life particularly under usage in hot ambient conditions. This paper discusses the various challenges and options of thermal management for the 48V battery pack based on the usage pattern and environmental conditions. The lifetime for a passively cooled battery pack is estimated for a typical Indian usage pattern. Active-air cooling is evaluated for the thermal management of the 48V mild-Hybrid battery pack. The tradeoffs are compared in terms of availability of hybrid functions and battery life.
Subramanian, Kannan, Naznin, Fahmida, Ramakrishnan, Ganesh Kumar
Thermal Uniformity of Pouch-Type Lithium Ion Batteries with NCM Cathode Materials under Different Operating Conditions2019-01-10004/2/2019
With the advantages of flexible size and high energy density etc., pouch-type lithium ion battery cells with large capacity have been found more and more applications in electric vehicles. For these large-scale battery cells, thermal uniformity is vital for their safety and cycle life. To be specific, temperature gradients are expected to cause different degradation rates of active materials in different areas, which is possible to cause early failure or even fire and explosion of the battery cell. Thus, it is necessary to illustrate the batterie’s thermal uniformity in detail under different operating conditions. This work investigated the thermal uniformity of two 36 Ah pouch-type NCM/C battery cells with different sizes using both the thermal imaging method and thermoelectric effect method with K-type thermocouples. Experimental results show that there is an obvious temperature gradient on the surface of the pouch-type battery cell. The temperature of the positive electrode is significantly higher than other regions, which denotes that cooling the electrodes could a possible and effective solution for battery thermal management system. The current rare and direction can both have obvious influence on the temperature gradients of the cells. Moreover, pouch-type cells with different sizes present differences in temperature uniformity. The sample in a long strip shape showed better performace in thermal uniformity than that in a near square shape. The battery thermal behavior presented in this work provides excellent data for the validation of electro-thermal models and could be helpful for the optimization of battery cells and the design of their thermal management systems.
Lin, Chunjing, Liu, Yifan, Zhang, Jinjie, Han, Liqiong, Fan, Bin, Luo, Yunjun, Wang, Fang
Sensorless On Board Cell Temperature Control for Fast Charging2019-01-07914/2/2019
Fast charging capability is one of the key requirements for the success of electric vehicles. Considering the growing energy storage capacity of automotive batteries, fast charging can only be achieved using high-power charging systems. This leads to increased power dissipation inside the battery cells. The resulting heat generation inside the battery cell is a critical effect, as cell safety, performance and life time strongly depend on cell temperature and current. This must be considered by a simultaneous current and thermal battery management strategy, which requires reliable information about the individual cell temperature. Sensorless cell temperature can be derived from the cell impedance, where the charging current profile is superimposed by an excitation current and the resulting cell voltages are observed by the battery management system (BMS). An efficient algorithm for the impedance and temperature calculation can be implemented in actual BMS. In this work, this concept is verified by fast charging experiments. The thermal properties of a prismatic cell for electric vehicle energy storage are investigated under real boundary conditions, including effects of active fluid cooling. For a more detailed thermal analysis and modeling, cell surface temperature distribution is monitored by a temperature sensor array. The internal and external cell temperature increase is analyzed for different fast charging profiles. 3-dimensional thermal modeling is used to determine the internal peak temperature from the average measured temperature for a given cell type and assembly. The results can be used to define fast charging and thermal management strategies that are optimized for safe operation and long life.
Haussmann, Peter, Melbert, Joachim
Full Protection Scheme and Energy Optimization Management of the Battery in Internal Combustion Engine Vehicles Based on Power Partitioning Model2019-01-12054/2/2019
As the only energy storage component in the internal combustion engine vehicles (ICEVs), the battery is lack of comprehensive supervision and effective protection. Excessive discharge or aging cannot be detected and dealt with, which may lead to damage of the battery, even startup failure of the vehicle. In this paper, a full protection and optimization management scheme of the battery is proposed, to achieve comprehensive protection of the battery and energy optimization. Firstly, power partitioning model of the battery is established to reveal the battery characteristics in different states, which divides the battery into several function zones. Then, based on the power partitioning model, over discharge protection and graded overcurrent protection method are proposed, to achieve full protection of the battery. Thirdly, energy optimization management strategy based on generator’s multimode operation is introduced. Finally, to verify the validity and feasibility of the proposed method, tests are performed on the vehicle and test bench. The results reveal that overcurrent protection and over discharge protection of the battery is achieved, and the vehicle start-up capability is assured. In the meanwhile, the optimized energy consumption is able to be realized with the proposed method.
Kong, Wei Wei, Luo, Yugong, Qi, Yunlong, Wang, Yongsheng
Optimizing Battery Cooling System for a Range Extended Electric Truck2019-01-01584/2/2019
Battery packs used in electrified automotive powertrains support heavy electrical loads resulting in significant heat generation within them. Cooling systems are used to regulate the battery pack temperatures, helping to slow down battery aging. Vehicle-level energy consumption simulations serve as a first step for determining the specifications of a battery cooling system based on the duty cycle and interactions with the rest of the powertrain. This paper presents the development of a battery model that takes into account the energy impact of heating in the battery and demonstrates its use in a vehicle-level energy consumption simulator to set the specifications of a suitable cooling system for a vehicle application. The vehicle application used in this paper is a Class 6 Pickup and Delivery commercial vehicle with a Range-Extended Electric Vehicle (REEV) powertrain configuration. The battery model, consisting of a State-of-Charge estimator and a thermal model for the battery pack's bulk temperature, is calibrated on the vehicle simulator based on bench test data for a passive cooling system. A model for an active liquid-cooling system is then developed, and its performance specifications are determined based on a chosen battery temperature increase target. The vehicle simulation results obtained with the two cooling systems demonstrate that although the active cooling system consumes slightly more energy due to the additional accessories that are needed to operate it, the battery temperature remains within tighter limits.
Arasu, Mukilan, Ahmed, Qadeer, Rizzoni, Giorgio
BEV Range: Challenges for Indian Driving Conditions2019-26-01271/9/2019
India is rapidly transitioning to environment friendly green mobility technology. This is evident from leapfrog move to Bharat Stage VI stringent emissions norms, by just providing a mere window of three years to the automotive industry. The challenge is not to manufacture new subsystems but is getting customized emission solution technology tested and validated for Indian conditions to meet BSVI emission norms by April 2020. With reference to recent reports published by NITI Aayog (Government of India Think Tank), xEV’s can be incentivized and promoted as an emission free solution. With internal combustion engine complex architectures to meet BSVI emission norms and proposed government incentive, many passenger car OEM’s are considering electric vehicle (EV) powertrain development. In view of this, a study was envisaged to estimate EV powertrain challenges for Pune (India) city real world driving conditions. Test data such as vehicle speed, engine speed was measured on conventional passenger car using data acquisition system for city routes. A conventional powertrain simulation model was developed using Ricardo IGNITE® which was then validated for MIDC fuel economy. An equivalent EV powertrain architecture such as motor rating, HV battery size was identified to maintain traction power, speed and electric range of 100 km. This identified EV architecture was implemented in simulation model along with battery thermal management & regenerative braking strategy. The EV simulation model was used to predict fuel and hence CO2 savings for MIDC and real-world drive condition. The study of Effect of real world driving conditions on range was also carried out. It was observed that electric vehicle is viable option for CO2 savings. Real world driving conditions impacts electric range mostly due to traffic conditions requiring repeated acceleration and braking events. This study could not focus on driving conditions observed in other Indian cities such as Mumbai, Delhi, etc. where driving pattern may be different. Also, this study has not considered PHEV architecture as it is the most complex in terms of hardware as well as controls. Study concludes that EV architectures are specific to application and driving conditions. A range of 100 km on one route can’t assure similar range for another route. Battery thermal management will present a trade-off to maintain EV range and battery life.
Umbarkar, Yogesh, Khalane, Hemant
Optimized Electrification Solution for App-Based Taxis in Indian Cities2019-26-01291/9/2019
The transportation needs in highly dense urban pockets is leading to high pollution islands in India. To address this issue, the emission legislations are becoming more stringent with an aim to reduce the emissions at national level. App based taxis are becoming lifeline for all major Indian cities. So far, these taxis are predominantly diesel powered compact cars. Thus, vehicle powertrain electrification is a good idea to improve local air quality in such urban pockets. While upgradation of internal combustion engines will add significant costs due to expensive exhaust after-treatment systems, electric motor driven taxis can be the ideal solution for emission reduction, as their operation is completely free of local pollutant emissions. However, the currently available electric vehicles are more expensive than the internal combustion engine powered counterparts. Against this backdrop, this paper focuses on optimizing battery electric vehicles for taxi segment requirements, and analyzes possible ways to make the technology affordable. The presented work begins with a Strengths, Weaknesses, Opportunities and Threads (SWOT) analysis for vehicle electrification, having clean urban mobility as central objective. Taxi driving data collected from Pune city driving is analyzed statistically to arrive at a real driving pattern for an app-based taxi operation. The driver demanded torque from the real world driving is used for drivetrain sizing. The powertrain losses and other accessory loads from the real driving measurements are included to define the maximum vehicle power requirement. The daily running distance, calculated based on the app-based taxi survey, forms the basis for the determination of the required energy storage system capacity. A cost optimization between 48 V and high voltage (100……400 V) energy storage systems and propulsion components is also included in the study, as are analyses of various battery charging infrastructure possibilities in Indian cities compared to the best practices available globally. There are hosts of subsidies provided by governments across the globe to make electrified powertrains affordable. The possibilities of binning different subsidies are also analyzed based on energy consumption of the proposed vehicle and current energy price levels. This paper considers tank to wheel efficiency with a focus on affordability of electrified powertrains in the urban taxi segment. The output from this work establishes the requirements for right sizing the electric vehicle components and for the promotional subsidies to strengthen the position of battery electric vehicle in the app-based taxi segment.
Apte, Rohin, Emran, Ashraf, Sharma, Vijay, Soundara Rajan, Ragupathi
Q&A19AUTP08_211/1/2019
Sean Stanley is one of a new generation of motorcycle engineers who are as fluent in battery cooling and electronics integration as their predecessors were in optimizing cam profiles and compression ratios. As Harley-Davidson's EV Systems chief engineer, Stanley, along with EV Platform chief Glen Koval and their teams, have brought the 2020 LiveWire e-bike from a bold concept in 2011 to production, which is getting underway at H-D's York, Pennsylvania, assembly plant. LiveWire is nothing like your granddad's Shovelhead, aside from the brand name on the faux ‘gas tank.’ There are five ECUs on board controlling seven rider-selectable and customizable ride modes. Rear-wheel lift mitigation is managed by a 6-axis inertial measurement unit (IMU). The 15.5-kWh Samsung SDI lithium-ion battery, liquid cooled 78-kW (108-hp) Magneti-Marelli permanent-magnet motor, 1400-watt SAE J1772 ‘Combo’ charging setup, 4.3-in. (109-mm) color thin-film display, and hollow-cast aluminum ‘exoskeleton’ chassis, represent just some of the topflight systems engineering that is the hallmark of this novel bike.
Energetic, Environmental and Range Estimation of Hybrid and All-Electric Transformation of an Existing Light Utility Commuter Aircraft2018-01-193310/30/2018
Today it is necessary to face the energetic, environmental, and safety-related issues of a significant industrial sector such as aeronautic one. It is a marginal contributor to today global GHG emissions (less than 3%), In any case, the associated impacts grows with the increase of air traffic with annual rate 5%. Consequently, aviation will need to face four fundamental problems for the future: 1 the overall impact of aviation is expected to grow up to 10÷15% of global GHG emissions by 2050; 2 the emissions of pollutants by commercial aviation affects the fragile atmospheric layers in the low stratosphere; 3 the increasing age of the flying fleet deals with increasing maintenance and safety issues; 4 the dependence on fossil fuels relates to problems of geopolitical instability and consequence volatility of prices. Substantial innovations are expected for both reducing energy consumption and environmental impacts of aviation and reducing the age of the fleets. They mostly relate to the decrease of weights and the introduction of environmental friendly propulsion systems, such as hybrid and all-electric propulsion. This paper will produce an assessment of different propulsive systems according to the first law of thermodynamics and environmental impacts. It assumes a well-tested light transport/commuter aircraft as reference architecture and produces a comparative analysis of different green propulsion systems including all electric and hybrid against actual aircrafts. The analysis assumes that the electric or hybrid configurations may not increase the overall mass of the aircraft. Energy model has been reformulated for the different configurations and considers both an analytical model based on basic flight mechanics and a new formulation of the Breguet range equation, which has been specifically formulated for both hybrid and all-electric airplanes.
Trancossi, Michele, Pascoa, Jose
An Adaptive Neuro-Fuzzy Inference System (ANFIS) Based Model for the Temperature Prediction of Lithium-Ion Power Batteries07-12-01-00018/14/2018
Li-ion batteries have been widely applied in the areas of personal electronic devices, stationary energy storage system and electric vehicles due to their high energy/power density, low self-discharge rate and long cycle life etc. For the better designs of both the battery cells and their thermal management systems, various numerical approaches have been proposed to investigate the thermal performance of power batteries. Without the requirement of detailed physical and thermal parameters of batteries, this article proposed a data-driven model using the adaptive neuro-fuzzy inference system (ANFIS) to predict the battery temperature with the inputs of ambient temperature, current and state of charge. Thermal response of a Li-ion battery module was experimentally evaluated under various conditions (i.e. ambient temperature of 0, 5, 10, 15 and 20 °C, and current rate of C/2, 1C and 2C) to acquire the necessary data sets for model development and validation. A Sugeno-type ANFIS model was tuned using the obtained data. The numbers of input membership functions (MFs) representing the three input parameters of this model are 1, 2, 3, respectively. The input and output MFs are Gaussian curve and linear types, respectively. The optimization method is a hybrid one which is a combination of the back-propagation and the least squares methods. Compared with the validating data, the ANFIS model was able to accurately predict the battery temperature under various operating conditions. With fewer sensors for data acquisition and less computation complexity, this method could be a possible tool for the online temperature prediction of power batteries in electric vehicle applications.
Fan, Bin, Lin, Chunjing, Wang, Fang, Liu, Shiqiang, Liu, Lei
Thermal Model of High-Power Lithium Ion Battery Under Freezing Operation2018-01-04454/3/2018
Lithium ion battery is considered as one of the most possible energy storage equipment for new energy vehicles (EV, HEV, etc.) because of the advantages of long cycle life, high power density and low self-discharge rate. However, under freezing condition high power battery suffers of significant performances losses. For example, they would suffer from significant power capability losses and poor rate performance, which would restrict the availability to delivery or to gain of high current in transient conditions. To evaluate those performance drawbacks and to make an efficient design, good mathematical models are required for system simulation especially for battery thermal management. In this paper, a three-dimensional homogenization thermal model of a 20 Ah prismatic lithium ion battery with LiFePO4 (LFP) cathode is described. This model particularly stresses on the high-ratio discharge property at low-temperature which could capture the shapes and dimensions of cell components and the spatial distributions of the temperatures. First, various discharge tests on one cell are carried out, and then, cell’s parameters and thermal characteristics are obtained. Ultimately, the three-dimensional thermal model for single-cell proposed is shown to be accurate by analyzing the simulation data and test results.
Xuan, Tang, Wei, Xuezhe, Dai, Haifeng, Venturi, Massimo
A Physics Based Thermal Management Model for PHEV Battery Systems2018-01-00804/3/2018
The demand for vehicles with electrified powertrain systems is increasing due to government regulations on fuel economy. The battery systems in a PHEV (Plug-in Hybrid-electric Vehicle) have achieved tremendous efficiency over past few years. The system has become more delicate and complex in architecture which requires sophisticated thermal management. Primary reason behind this is to ensure effective cooling of the cells. Hence the current work has emphasized on developing a “Physics based” thermal management modeling framework for a typical battery system. In this work the thermal energy conservation has been analyzed thoroughly in order to develop necessary governing equations for the system. Since cooling is merely a complex process in HEV battery systems, the underlying mechanics has been investigated using the current model. The framework was kept generic so that it can be applied with various architectures. In this paper the process has been standardized in this context. Under this generic framework the theoretical model was extended to a Simulink model which can be integrated with existing cooling network (i.e. Flowmaster) for the PHEV system. Besides predicting coolant outlet it is also important to predict cell-level temperatures in the battery systems. The integrated model will be able to fulfill these goals. In order to establish the model’s applicability, the physics based model was correlated with vehicle level test data under different drive cycles. The results exhibited good agreement with the test data which provides significant confidence in the proposed framework and its future developments.
Rahman, Rezwanur, Rahman, Sadek
Development of General Motors’ eAssist Gen3 Propulsion System2018-01-04224/3/2018
General Motors’ 3rd generation eAssist propulsion systems build upon the experience gained from the 2nd generation 115v system and the 1st generation 36v system. Extensive architectural studies were conducted to optimize the new eAssist system to maintain the performance and fuel economy gains of the 2nd generation 115v system while preserving passenger and cargo space, and reducing cost. Three diverse vehicle applications have been brought to production. They include two similar pickup trucks with 5.3 liter V8 engines and 8 speed transmissions, a 4-door passenger car with 2.5 liter 4 cylinder normally aspirated gasoline engine and a 6-speed automatic transmission, and a crossover SUV with a 2.0-liter turbocharged engine and 9 speed transmission. The key electrification components are a new water cooled induction motor/generator (MG), new water cooled power electronics module, and two major variants of 86v lithium ion battery packs. All three applications share variations of the same components, showing the bandwidth of the 3rd generation system. The engines include special dual tensioner accessory drive systems to couple the MG to the crankshaft. The transmissions are all modified to support the eAssist system. The torque based control system of the 2nd generation eAssist system was carried into these applications and integrated with the latest GM corporate common electrical and controls architectures.
Cottrell, Daniel, Miller, Michael Andrew, Oury, Andrew, Staley, Eric, Mui, Danny, Osterkamp, Dale, Poulos, Stephen
Degradation Testing and Modeling of 200 Ah LiFePO 4 Battery2018-01-04414/3/2018
In this paper, a degradation testing of a lithium-ion battery used for an electric vehicle (EV) is performed and the capacity fade is measured over 400 cycles. For this, a 200 Ah LiFePO4 battery cell is tested under ambient temperature conditions with charge-discharge cycles at rate of 1C (constant current). Additionally, individual cell characterization is conducted using a C/25 (0.8A) charge-discharge cycle and hybrid pulse power characterization (HPPC). Later, the Thevenin battery model was constructed in MATLAB along with an empirical degradation model and validated in terms of voltage for all cycles. It is also found that the presented model closely estimated the profiles observed in the experimental data. Data collected from the experimental results showed that a capacity fade occurred over the 400 cycles and the discharge capacity at the end of 400th cycle is found to be 137.73 Ah. The error between model/experiments is found to be less than 3.5% for all cycles.
Panchal, Satyam, Rashid, Mahir, Long, Frank, Mathew, Manoj, Fraser, Roydon, Fowler, Michael
A Computational Study on the Critical Ignition Energy and Chemical Kinetic Feature for Li-Ion Battery Thermal Runaway2018-01-04374/3/2018
Lithium-ion (Li-ion) batteries and issues related to their thermal management and safety have been attracting extensive research interests. In this work, based on a recent thermal chemistry model, the phenomena of thermal runaway induced by a transient internal heat source are computationally investigated using a three-dimensional (3D) model built in COMSOL Multiphysics 5.3. Incorporating the anisotropic heat conductivity and typical thermal chemical parameters available from literature, temperature evolution subject to both heat transfer from an internal source and the activated internal chemical reactions is simulated in detail. This paper focuses on the critical runaway behavior with a delay time around 10s. Parametric studies are conducted to identify the effects of the heat source intensity, duration, geometry, as well as their critical values required to trigger thermal runaway. The characteristics of different concentrations and heat release from each chemical reaction in the scenario of thermal runaway are discussed. Based on the current kinetic model, the simulation results further suggest that the concentration of negative-electrolyte is closely related to the occurrence of thermal runaway. This study provides useful guidance on the simulation and control of thermal runaway of battery systems.
Zhang, Liwen, Xu, Meng, Zhao, Peng, Wang, Xia
Self-Discharge Observation for Onboard Safety Monitoring of Automotive Li-Ion Cells: Accelerated Procedures and Application Concept2018-01-04494/3/2018
Recent advances in energy density of Li-ion cells together with high-current fast charging ask for improved strategies for onboard safety and reliability observation of the cells. Potential degradation effects are stimulated by lithium plating and dendrite growth. The latter may ultimately cause an internal short circuit of the cell and can lead to serious damage. Increased self-discharge is an early indicator for safety-critical cell conditions. In this work, accelerated methods for self-discharge determination of Li-ion cells are presented. They are based on the analysis of cell voltage gradients during idle periods and can be applied in state-of-the-art battery management systems (BMS) performing low-drift measurement. However, transition into the idle state after driving requires a settling time of several hours before the voltage gradient can be extracted. For the new accelerated self-discharge determination, a model-based approach was chosen, which also considers aging effects of the open circuit voltage (OCV) and the cell capacity. The self-discharge behavior of more than 100 automotive cells is studied using the presented methods during a 48-week aging experiment with real driving current profiles. A fast leakage detection procedure is based on the voltage gradient comparison of cell stacks under identical load and temperature conditions. For the application of onboard electric vehicles, a simulation-based case study is presented, which shows that detection of high-leakage cells is possible using state-of-the-art battery monitoring integrated circuits.
Haussmann, Peter, Melbert, Joachim
Solar Panels on Electrified Vehicles: Applications and Off-Cycle CO 2 Credit2018-01-04264/3/2018
The objective of this article is to provide a comprehensive investigation of the opportunities and applications of using solar panels in electrified vehicles. The use of photovoltaic (PV) panels as an auxiliary energy source of on-board fuel in plug-in hybrid electric vehicles (PHEVs), full hybrid electric vehicles (FHEVs), and battery electric vehicles (BEVs) is investigated. The electrical architectures and the benefits of various possible applications are presented, such as active vehicle cabin ventilation, charging the low voltage battery, and charging the high voltage (HV) traction battery to extended driving ranges. In addition, the possibility of using PV panels to cool down the HV battery in extreme temperature environments is also investigated, supported by experimental tests used to properly model the thermal behavior of the HV battery and the effect of the cooling. This work also analyzes the CO2 off-cycle credits made available, by the United States Environmental Protection Agency (EPA) and European Commission (EC), for automakers, which equip their vehicles with solar panels. Finally, the challenges and market outlook that make the on-board solar panel a more economical and effective solution for electrified vehicles are highlighted.
Abdelhamid, Mahmoud, Rhodes, Kevin, Christen, Erik, Kok, Daniel
Modeling and Validation of 48V Mild Hybrid Lithium-Ion Battery Pack2018-01-04334/3/2018
As part of the midterm evaluation of the 2022-2025 Light-Duty Vehicle Greenhouse Gas (GHG) Standards, the U.S. Environmental Protection Agency (EPA) developed simulation models for studying the effectiveness of 48V mild hybrid electric vehicle (MHEV) technology for reducing CO2 emissions from light-duty vehicles. Simulation and modeling of this technology requires a suitable model of the battery. This article presents the development and validation of a 48V lithium-ion battery model that will be integrated into EPA’s Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) vehicle simulation model and that can also be used within Gamma Technologies, LLC (Westmont, IL) GT-DRIVE™ vehicle simulations. The battery model is a standard equivalent circuit model with the two-time constant resistance-capacitance (RC) blocks. Resistances and capacitances were calculated using test data from an 8 Ah, 0.4 kWh, 48V (nominal) lithium-ion battery obtained from a Tier 1 automotive supplier, A123 Systems, and developed specifically for 48V mild hybrid vehicle applications. The A123 Systems battery has 14 pouch-type lithium-ion cells arranged in a 14 series and 1 parallel (14S1P) configuration. The RC battery model was validated using battery test data generated by a hardware-in-the-loop (HIL) system that simulated the impact of MHEV operation on the A123 systems 48V battery pack over U.S. regulatory drive cycles. The HIL system matched charge and discharge data originally generated by Argonne National Laboratory (ANL) during chassis dynamometer testing of a 2013 GM Chevrolet Malibu Eco 115V MHEV. All validation testing was performed at the battery test facility (BTF) at the U.S. EPA National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, Michigan. The simulated battery voltages, currents, and state of charge (SOC) of the HIL tests were in good agreement with vehicle test data over a number of different drive cycles, and excellent agreement was achieved between RC model simulations of the 48V battery and HIL battery test data.
Lee, SoDuk, Cherry, Jeff, Safoutin, Michael, McDonald, Joseph, Olechiw, Michael
Temperature Control Characteristics of Automotive Power Battery Based on R-1233zd(E)’s Flowing Phase Change Heat Transfer2018-01-11914/3/2018
Li-ion power battery is the core component of the electric vehicle power system, and the battery temperature will increase because of the electrochemical reaction of the Li-ion battery. The heat accumulates inside of the battery, which can degrade the working performance of the power battery and shorten the battery cycle life. At present, the wind cooling technology is relatively mature. However, it cannot achieve ideal heat dissipation effect under the working conditions of the high-power or high ambient temperature. In this research, the battery thermal management is carried out by the characteristics of the working fluid’s flowing phase change heat transfer. The phase change working fluid is R-1233zd(E) which is a kind of environmentally friendly liquid with nonconductive and nonflammable. It can achieve the purpose of controlling the battery’s temperature using the characteristics of isothermal heat absorption under different gas phase rate of phase change working fluid. In this paper, the mathematical model of heat generation about the lithium iron phosphate battery is established by analyzing the battery heat generation mechanism. Then, the mathematical model of the R-1233zd(E) phase change heat transfer is established for researching the heat-transfer characteristics of battery under different discharge rate conditions. Finally, design a battery heat dissipation system based on the R-1233zd(E) phase change heat transfer and perform the temperature control experiment of the battery under different discharge rate. The results show that the temperature changes on the surface of the battery can be controlled within 2 degrees Celsius by the R-1233zd(E)’s flowing phase change heat transfer. Compared with wind cooling, this way can make the battery’s surface temperature fluctuation smaller.
Huang, Bo, Xu, Yongbing, Zheng, Xingmang, Kuang, Jianjie, Quan, Jiakang, Huang, Shiping, Tan, Gangfeng
Nickel Cadmium Vented Rechargeable Aircraft Batteries (Non-Sealed, Maintainable Type)AS8033 (Current)10/26/2017
The Nickel Cadmium battery covered by this Aerospace Standard is the type which is generally, although not exclusively, used for engine starting purposes in turbine-powered aircraft and/or on aircraft with turbine type Auxiliary Power Units. This turbine starting function requires high power delivery rates from the battery for 15 to 30 seconds or more for each engine start. This same battery may also be used at lower power delivery rates, as the final redundant source of emergency electrical energy for the operation of essential flight equipment for required periods of 30 to 60 minutes. The battery generally consists of a group of plastic jarred cells contained within an enclosing battery case. They are electrically connected in series with each other and usually terminate in an electrical connector mounted in the case front wall. The battery case may be secured to the aircraft structure by any of a number of clamping techniques. The outer or battery case is ventilated to purge it of gases, such as the hydrogen and oxygen produced in overcharge. This ventilation may be of the closed air circuit type which is accomplished by passing air through the case and then exhausting these gases overboard. An alternative method, which is used to purge these gases from the battery case, is to encourage their natural convective diffusion with the ambient air in the compartment which contains the battery, by use of relatively open construction of the battery case and cover. The battery, while in service, is generally charged by one of two methods: 1) by direct electrical connection to the D.C. bus which in turn is supplied by a regulated/controlled “constant potential” source such as a D.C. generator, or 2) from a dedicated “constant current” source in a system whereby the battery response voltage controls the termination, and also possibly the reinitiation, of that charge current. The “control” voltage of the “constant current” charge system or the regulated supply voltage of the “constant potential” system, may be compensated, or automatically adjusted, according to cell temperature, in order to more accurately control the state of “full charge” and minimize the amount of water used during overcharge. These batteries may be equipped internally with heaters, thermal switches, thermal sensors, etc. for performing various functions both inside the battery and/or in the aircraft/battery system. In addition, some battery types have air passages between cells with appropriate plenum chambers above and below the cells, for more positive responsive control of cell temperature, by the passage of conditioned air.
AE-7B Power Management, Distribution and Storage
Discussion on Charging Control Strategy for Power Battery at Low Temperatures08-07-01-000410/8/2017
In the case of electric vehicles, due to the charging current limitation of lithium battery at low temperatures (below -20°C), it has been proposed to heat the battery pack up to a suitable temperature range before charging through a liquid-heating plate with PTC. However, at a low state of charge (SOC), there is a question which one could take the place of battery pack to supply power for PTC when heating. So that off-board charger (OFC) has been considered to supply power for PTC in this article. In order to control the current charging into the battery pack as less as possible at low temperatures, three control schemes of battery management system (BMS) are proposed and compared. Scheme 1: BMS controls the value of charging current request close to the working current of PTC. Scheme 2: BMS controls the value of charging voltage request to reach a state of relative balance. Scheme 3: BMS disconnects the pack from the charger and keeps the connection between PTC and charger. The functions of the three schemes above have been verified by simulation tests and vehicle tests. The results showed: the first two schemes can supply the power for PTC successfully. However, the third one can’t keep PTC working properly due to a power-down fault judged by OFC. As a result, by comparison, Scheme 2 (the voltage control scheme) can more effectively control the current charging into the battery pack as less as possible.
Xiaojun, Liu, Jinpeng, Yu, Xia, Yang, Daoming, Wu
Powertrain Solutions for Electrified Trucks and Buses2017-01-19375/10/2017
Local air pollution, noise emissions as well as global CO2 reduction and public pressure drive the need for zero emission transport solutions in urban areas. OEMs are currently developing battery electric vehicles with the focus to provide emission free urban transportation combined with lowest total cost of ownership and consequently a positive business case for the end customers. Thereby the main challenges are electric range, product cost, system weight, vehicle packaging and durability. Hence they are the main drivers in current developments. In this paper AVL describes two of its truck and bus solutions - a modular battery concept as well as a concept for an integrated electric axle. Based on the vehicle requirements concept designs for both systems are presented.
Schreier, Heimo, Aliefendioglu, Burak, Perthen, Roger, Tochtermann, Jürgen
The Safe Handling of High Voltage Electric and Hybrid Vehicle Components within the Global Vehicle Recycling Industry2017-01-12753/28/2017
Global sales of electric and hybrid vehicles continue to grow as emission legislation forces vehicle manufacturers to build cleaner vehicles, with some 8 million already in service. Hybrid and Electric vehicles contain some of the most complex systems ever used in the automotive field, sophisticated and unique electric hybrid systems are added to modern motor vehicles which are already quite complex. As these vehicles reach the end of their lives they will be processed by the global vehicle recycling industry and the high voltage components will be reused, recycled or re-purposed. This paper explores safe working practices for businesses involved in a global marketplace who are completing battery disabling, removal, disassembly, storage and shipping; includes the various technologies and safe working practices along with some of the legal restrictions on dismantling, storage and shipping of high voltage batteries around the world. The paper will also explore how detailed safety, dismantling, storage and shipping information is currently made available to the vehicle recycling community and how this can be improved in the future to enhance the safety of people handling, dismantling, storing and shipping high voltage electric and hybrid components.
Hobbs, David, Ossenkop, Charles, Latham, Andy
Numerical Investigations of Vehicle Climate Control Strategies Impact on Plug-In Electrical Vehicle Battery Range2017-01-01903/28/2017
The range of Plug-In Electric Vehicles (EVs) is highly influenced by the electric power consumed by various sub systems, the major part of the power being used for vehicle climate control strategies in order to ensure an acceptable level of thermal comfort for the passengers. Driving range decreases with low temperatures in particular because cabin heating system requires significant amount of electric power. Range also decreases with high ambient temperatures because of the air conditioning system with electrically-driven compressor. Both thermal systems reduce EV driving range under real life operating cycles, which can be a barrier against market penetration. The structure of a vehicle is capable of absorbing a significant amount of heat when exposed to hot climate conditions. 50-70% of this heat penetrates through the glazing and raises both the internal cabin air temperature and the interior trim surface temperature. In this paper, an integrated 1D/3D CFD approach is proposed to evaluate sensitivity of various vehicle climate control strategies (Cabin cool down) impact on battery energy state of charge and consequent driving range. Additionally, effects of ambient temperature and choice of glazing materials on climate control performance and its impact on driving range is studied.
Kandasamy, Neelakandan, Whelan, Steve
A Segregated Thermal Analysis Method for Liquid-Cooled Traction Batteries2017-01-06293/28/2017
Thermal modeling of liquid-cooled vehicle traction battery assemblies using Computational Fluid Dynamics (CFD) usually involves large models to accurately resolve small cooling channel details, and intensive computation to simulate drive-cycle transient solutions. This paper proposes a segregated method to divide the system into three parts: the cells, the cold plate and the interface between them. Each of the three parts can be separated and thermally characterized and then combined to predict the overall system thermal behavior for both steady-state and transient operating conditions. The method largely simplifies battery thermal analysis to overcome the limitations of using large 3D CFD models especially for pack level dynamic drive cycle simulations.
Kuo, John, Garfinkel, George
Items per page:
1 – 50 of 169