Browse Topic: Thermal runaway

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Recommendations and Background Material for Battery Package TestingAIR6840 (Current)11/26/2025
AS 6413 and slash sheets /1 & /2 hold the main information for testing of battery packaging. This document holds further information and expansion of philosophy, clarification etc. surrounding the testing and industry needs.
G-27 Lithium Battery Packaging Performance
Dynamic Drop Testing of eVTOL Energy Storage Systems Part 1: Drop Test Data SummaryF-0081-2025-00425/20/2025
Researchers at the National Aeronautics and Space Administration (NASA) have conducted a series of module-level tests on electric Vertical Take-off and Landing (eVTOL) Energy Storage Systems (ESS) for the generation of dynamic impact data to support standards developments. The tests were conducted on zero-state-of-charge Electric Power Systems (EPS) Electric Propulsion Ion Core (EPIC) modules at the National Institute for Aviation Research (NIAR), utilizing the NIAR outdoor drop test setup and personnel. Four total tests were conducted. For each test, the module was dropped at a specific orientation from a height of 50 feet while connected to a guided trolley in order to assess the effects of a 50-foot drop test on the ESS. The test velocities ranged between 46.9 and 52.8 ft/s with impact angles ranging between a flat, zero-degree impact and 18 degrees. Data were recorded in the form of temperatures, cell-level voltage, module level acceleration and digital image correlation from the tests. Accelerations were in the range of 1,500 g for a few millisecond duration, which were indicative of a shock type loading condition. No modules entered thermal runaway, and post-test inspections revealed a variety of internal deformations and damage present in the various modules tested, with specific damage occurring for specific orientations. The modules were ranked according to a custom developed scoring rubric developed by utilizing the test and post-test inspection results. The results were compiled, reported, and will be used to guide future ESS testing. Part 1 discusses the loading environments in the modules, while Part 2 will discuss the deformation and damage in the modules.
Littell, Justin, Gardner, Nathaniel, Ellafrits, Shay
Experimental Evidence to Influence Design of Novel Low Lubrication Method for Rotorcraft Secondary Lubrication SystemsF-0081-2025-02795/20/2025
This paper presents experimental research aimed at developing novel low lubrication methods for rotorcraft and jet engines, focusing on sustaining minimal lubrication to prevent catastrophic bearing failure during loss of lubrication (LoL) events or to increase fuel consumption performance on once-through, fuel-oil bearing lubrication engines. Utilizing two high-speed bearing test rigs simulating low and high thrust class engine conditions, the study establishes lower bounds for oil flow rates necessary to maintain thermal stability and prevent thermal runaway in hybrid ball bearings. These findings inform the design of the Zulu Pod (ZPod), a passively driven, self-contained oil delivery system that uses engine compressor bleed air to precisely meter lubricant flow. Engine test stand results demonstrate that replacing traditional fuel-oil lubrication with the ZPod system reduces thrust specific fuel consumption (TSFC) by an average of 7%, with up to 11% savings, without compromising engine thrust or bearing health. The ZPod offers a simplified, efficient alternative to fuel-lubricated systems by eliminating fuel diversion for lubrication, enhancing fuel efficiency, and maintaining bearing performance in attritable or single-use engines. Additionally, the study highlights the potential of minimal lubrication supplied by the ZPod to extend operational life during LoL scenarios, enabling safer aircraft recovery. Future work will focus on extending testing to higher thrust classes and optimizing ZPod designs for broader applications.
Boersma, Pieter, Currier, Todd, Ferrante, Jason, Rosenthal, Julius
Basic Science and Art of Aircraft Wreckage ReconstructionR-4804/23/2025
Basic Science and Art of Aircraft Wreckage Reconstruction is a unique title which addresses important aspects of investigating crashes, who does this kind of work, and how a healthy attitude and open mind are required to properly perform investigations. It also discusses what to expect from the on-scene part of the investigation, and the fundamental approaches to common types of wreckage reconstruction. Written by Don Knutson, a veteran of this industry, Basic Science and Art of Aircraft Wreckage Reconstruction is intended for the practitioner, student, or those who are simply curious about how aircraft wreckage is reconstructed. Full references are provided in the various chapters for additional reading and research. Many examples of aircraft crash scenarios and circumstances are presented in a "generic" form but relate to actual investigations, which should prove as a useful investigative resource whether you are an apprentice or an experience professional with a government aviation agency (NTSB, AAIB, FAA, etc.), an aircraft/engine/component manufacturer, military branch, insurance company, law enforcement agency, or a law firm. Basic Science and Art of Aircraft Wreckage Reconstruction is a must-read book for all who are passionate about the subject and want to understand how this activity actually happens in the field.
Knutson, Donald F.
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
Portable Emergency Lighting Systems for Flight Crew MembersARP1798B (Historical)7/14/2020
The purpose of this SAE Aerospace Recommended Practice (ARP) is to recommend general design and performance characteristics for hand-held portable, emergency lighting systems (note: the portable portion of this system that contains the lamp and reflector will be identified throughout the remainder of this document simply as a “flashlight”) intended for use by crew members of commercial aircraft during any emergency situation, within or outside of the aircraft cabin, where emergency lighting is required.
A-20C Interior Lighting - Test
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
48 V High-power Battery Pack for Mild-Hybrid Electric Powertrains2020-01-04414/14/2020
Mild hybridisation, using a 48 V system architecture, offers fuel consumption benefits approaching those achieved using high-voltage systems at a much lower cost. To maximise the benefits from a 48 V mild-hybrid system, it is desirable to recuperate during deceleration events at as high a power level as possible, whilst at the same time having a relatively compact and low cost system. This paper examines the particular requirements of the battery pack for such a mild-hybrid application and discusses the trade-offs between battery power capabilities and possible fuel consumption benefits. The technical challenges and solutions to design a 48 V mild-hybrid battery pack are presented with special attention to cell selection and the thermal management of the whole pack. The resulting battery has been designed to achieve a continuous-power capability of more than 10 kW and a peak-power rating of up to 20 kW. The pack has been built and has been subjected to a series of tests at a range of ambient temperatures. The performance of the pack has been validated and the main characteristics, such as the internal resistance and capacity have also been established. The performance targets for the pack have been achieved. Further testing is underway to fully characterize the pack’s capabilities and characteristics, after which it will be installed into MAHLE’s 48 V eSupercharged demonstrator car.
Hall, Jonathan, Borman, Stephen, Hibberd, Benjamin, Bassett, Michael, Reader, Simon, Berger, Martin
Dynamic Simulation for LFP Pouch Batteries Coupled Mechanics-Electrics-Thermodynamics under Mechanical Abuse2020-01-13324/14/2020
The safety design of batteries, an important part in passive safety development of electric vehicle, is difficult in practical project application because of complex structure inside and Multi-physics reactions coupled mechanics-electrics-thermodynamics under mechanical abuse. An efficient computational model of batteries that can be attached to model of vehicle used for collision simulation is needed. In this work, four types of Multi-physics battery models (detailed computational model, simplified representative-sandwich model, composite layered model and simplified layered model) of pouch cell with LiFePO4 system are established in a commercial finite element software LS-DYNA (usually used for vehicle collision simulation). And the difficulties of modeling, resource demanded for calculation, accuracy of results (in mechanics, electrics and thermodynamics) in the four models are compared. In detail, based on quasi-static mechanical experiments of positive and negative current collectors, current collectors with active materials and separators, the corresponding constitutive models and material cards are established. And a one-way coupling methodology is adopted for the Multi-physics simulation. We use the thickness deformation of separators and distance between positive and negative current collectors in one circuit achieved from the dynamic indentation experiment as the criteria for short-circuit. The mechanical simulation predicts the deformation of battery cell. The electrical and thermal simulation predicts resistive heating problems after short-circuit onset and propagation of heat in the whole cell. Results show that these models can describe battery behavior from deformation to thermal propagation under dynamic mechanical abuse well. And an efficient method to simplify models of battery cell for engineer application of battery-package or vehicle simulation is present in the end
ZHANG, Ruiyu, Wang, Tao, Deng, Chenghao, Jin, Guoqing, Xiao, Heping, Zhang, Yanbing
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
Mechanical Response of Laterally-Constrained Prismatic Battery Cells under Local Loading2020-01-02004/14/2020
The crash safety of lithium-ion batteries has received great attention in recent years because of their growing popularity in electric vehicles. However, the safety issues of prismatic batteries have not been thoroughly studied; in particular, the mechanical responses of prismatic battery cells with lateral constraints under varied loading conditions still remain unclear. In this study, indentation tests are conducted to study the mechanical response of prismatic battery cells. Fixtures providing lateral constraint which simulates the real packing situation in battery module are designed. Firstly, the effects of lateral constraints on coupled mechanical and electrical responses of prismatic battery cells are analyzed and discussed. Secondly, dynamic indentation tests of prismatic cells with lateral constraints are carried out. The response of the stacked batteries under local loading is revealed. Thirdly, non-destructive X-ray computed tomography imaging technique is employed to detect the fracture patterns in battery cells caused by indentation. The results of indentation tests indicate that the indentation depth and the peak force for the battery internal failure are affected by the side constraint conditions and the responses of battery cells vary under different loading speeds. Also, the XCT scanning results of the samples clearly show the different levels of internal damage and fracture patterns under varied conditions. The detailed mechanical responses of the prismatic battery cell disclosed in the present study can provide support for modeling and protection of batteries under side impact.
Xiao, Feiyu, Xing, Bobin, Xia, Yong
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
Design of a Flexible Hybrid Powertrain Using a 48 V-Battery and a Supercapacitor for Ultra-Light Urban Vehicles2020-01-04454/14/2020
Global warming has put the transport sector, a major contributor of CO2 emissions, under high pressure to improve efficiency. In this context, ultra-light vehicles weighting less than 500 kg, as well as hybrid powertrains, are nowadays seen as promising development trends. The design process of the powertrain of a vehicle combining the advantages of the two concepts is presented in this paper. Through a performance study based on a simple MATLAB model, and mathematical simulation, a proposal is made. A powertrain using a battery and supercapacitor 48V dual power source network, two electric motors and clutches to switch between conventional, parallel, series and full electric modes proves to be an interesting system in terms of performance and costs. A simulation study conducted on a scenario with different outcome possibilities showed that high modularity of the system allows to achieve fuel efficiencies equivalent to approximately 3 l/100 km on the Artemis cycle. Finally, integration, packaging and cost are considered and some hints for further powertrain efficiency improvements are presented.
El Ganaoui-Mourlan, Ouafae, Miliani, El Hadj, Carlos Da Silva, Daniel, Couillandeau, Matthieu, Gonod, Charlie, Miller, Guillaume
Numerical Modeling of Lithium-Ion Battery Cells and Modules Subjected to Low Speed Indentation2020-01-04514/14/2020
Lithium-ion (or Li-ion) battery systems are being increasingly used as the main power source in new generation hybrid and electric vehicles. Their mechanical integrity under abuse loading conditions is very important for vehicle safety design. In this research, a computational study was performed to simulate mechanical tests on vehicle battery cells and modules. The tests were conducted on commercial Li-ion battery cells and entire modules at low speed using a high capacity material testing system. Based on loading and boundary conditions during the tests, finite element (FE) models using the explicit FEA solver LS-DYNA, were developed. The model predictions demonstrated reasonable agreement in terms of failure modes and force-displace response at both cell and module levels. With this newly developed numerical model for the entire battery module, a parametric study was performed to investigate the effect of small design modifications on its overall behavior subject to punch penetration.
Zhu, Feng, Du, Xianping, Lei, Jianyin, Audisio, Lorenzo, Sypeck, David
Evaluation of External Short-Circuit Safety of NCM/C Li-Ion Power Battery under Different State of Health2020-01-04544/14/2020
With the increasing frequency of fire incidents of electric vehicles, the safety of power batteries has attracted more and more attention. At present, the research on the safety of power batteries is mainly focused on fresh batteries. As the state of health of batteries deepens, how the safety of the battery evolves is not clear enough so far. This paper analyzes the external short-circuit safety of a NCM/C rectangular battery under different state of charges. The results show that when the cycle number is less than 800, the maximum temperature of the battery during short-circuit is below 130 °C. The main failure mode of the battery is bulging in volume or opening of the explosion-proof valve and there is no obvious regularity between the failure mode with the cycle life. However, when the cycle number reaches 1000, the battery goes into thermal runaway during the safety test. In specific, the explosion-proof valve opens, and a large amount of smoke is sprayed, and the surface temperature of the battery reaches 350 °C with obvious burn marks. The research in this paper shows that when the battery ages to 85% state of health, its external short-circuit safety may have some inflection point, and its safety will be significantly degraded. Special attention should be paid to the safety of the aged batteries in operation.
Liu, Lei, Lin, Chunjing, Yang, Peixia, Wang, Fang, Fan, Bin
Dynamic Load Identification for Battery Pack Bolt Based on Machine Learning2020-01-08654/14/2020
Batteries are exposed to dynamic load during vehicle driving. It is significant to clarify the load input of the battery system during vehicle driving for battery pack structural design and optimization. Currently, bolt connection is mostly applied for battery pack constraint to vehicle, as well as for module assembly inside the pack. However, accurate bolt load is always difficult to obtain, while directly force measurement is expensive and time consuming in engineering. In this paper, a precise data driven model based on Elman neural network is established to identify the dynamic bolt loads of the battery pack, using tested acceleration data near bolts. The dynamic bolt force data is measured at the same time with the acceleration data during vehicle running in different driving conditions, utilizing customized bolt force sensors. A data preprocessing method synthesizing Wavelet denoising method and machine learning algorithm is designed to improve model precision under dynamic condition. Parts of the pretreated acceleration and force data that obtained in various driving conditions are employed for model training, while the rest for model validation. Meanwhile, an index is introduced to quantitatively assess the identification accuracy against the measured force data. The identified loads show good consistency with the tested data. The error of the estimated bolt force result is within 20%. Finally, the reliability and generalization of the method are discussed. This method in this paper does not rely on prior known structural characteristics, and may be further developed for mechanical monitoring and diagnosis in battery modules in the future.
Liu, Ruixue, Hou, Zhichao, Wang, Shuyu, Sheng, Deke, Liu, Yuan
Multiple Sensors Aid in Development of an Electrical Vertical Takeoff and Landing AircraftTBMG-361573/1/2020
Beta Technologies (South Burlington, VT) has built a prototype Electrical Vertical Takeoff and Landing aircraft (eVTOL) and is putting it through the wringer. They are using wireless sensor systems from Parker LORD, MicroStrain® Sensing Systems (Williston, VT) to monitor the structures and functions of the prototype, both on a test stand and in flight.
Replacement of a 50cc Two-stroke Engine with an Electric Powertrain2019-32-06231/24/2020
As global regulations look to create a dramatic reduction in CO2 emission and other forms of pollution, companies with products that rely on engine technology must be ready to take on the electrification challenge. Applications that remain using two-stroke engine technology continue to exist due to their very high power density requirements. However, their history of higher pollution compared to four-stroke engines makes them a target to be regulated out of existence. Such high power two-stroke applications include high performance off-road motorcycles. In this type of product, electrification can solve not only pollution challenges but market challenges, such as ridership and public perception. By addressing the core problems presented by the two-stroke engine and turning challenges into opportunity, a strong attraction is created to convert a two-stroke engine motorcycle to an electric vehicle. With Automotive electric vehicle technology paving the way, the basis for cost effective electric motorcycle powertrain is explored for a 50cc off-road motorcycle application. The 50cc engine and motorcycle represent a special product where size, performance, and cost have a high sensitivity. The 50cc product also represents an area of great opportunity for the product as it is connected to the youth riding segment that establishes the future of motorcycle riding. With both strong opportunity and strong challenges, the electrification solution for a 50cc application provides broad justification for mass market adoption across the motorcycle industry. Challenges will be presented towards a OEM level product where design change is to be minimized without compromising performance. Various challenges include system design, packaging, supply chain, product lifecycle, competition readiness, safety, and cost. Opportunities will be discussed in the context of how the electrified powertrain can create a better product for the rider and solve challenges to enable the next generation of motorcycling. These opportunities include manufacturing advantages, environmental harmony, and new features.
Beeker, Jesse
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
Novel electrochemical capacitors with high-energy density using intercalated metal-organic framework electrodes2019-01-226012/19/2019
The energy-density improvement of capacitors while maintaining high power, long-term-cycle stability and safety is challenging. Asymmetric capacitors using non-faradaic and intercalation electrodes are proposed in order to achieve this. However the reported asymmetric capacitors with graphite-based negative electrode have a safety risk, which is an internal short circuit due to Li deposition when further high-energy density is performed. Here asymmetric capacitors consisting of intercalated metal-organic frameworks (iMOFs) negative operating potential range of 0.5-1.0 V vs. Li/Li+ that enable Li deposition reduction and activated carbon positive electrodes is proposed to construct a high volumetric energy (ca. 60 Wh L-1) and power densities with safety.
Ogihara, Nobuhiro
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
Battery experts: solid-state EV tech could be five years out19AUTP11_1111/1/2019
Solid-state batteries are the “reach” energy-storage technology slated to take electric vehicles (EVs) - and to a lesser extent, other consumer-electronic products - to the next level. And at September's 2019 Battery Show of North America, speaker panels and presentations about solid state certainly were in abundance. Just one problem: experts at the show's Solid State Battery Feasibility roundtable discussion where brutally realistic in agreeing the technology won't meet criteria for mass-production EVs for at least five years. The reasons for the five-year wait are manifest, but the two primary factors are familiar to the automotive sector: cost and manufacturability. Nonetheless, most experts here agree that solid-state batteries for EVs certainly are not an “if,” but a “when.” One analyst estimate indicates $500 million was invested in solid-state battery ventures in 2018 alone.
Visnic, Bill
Hybrid and EV First and Second Responder Recommended PracticeJ2990_201907 (Current)7/29/2019
xEVs involved in incidents present unique hazards associated with the high voltage system (including the battery system). These hazards can be grouped into three categories: chemical, electrical, and thermal. The potential consequences can vary depending on the size, configuration, and specific battery chemistry. Other incidents may arise from secondary events such as garage fires and floods. These types of incidents are also considered in the recommended practice (RP). This RP aims to describe the potential consequences associated with hazards from xEVs and suggest common procedures to help protect emergency responders, tow and/or recovery, storage, repair, and salvage personnel after an incident has occurred with an electrified vehicle. Industry design standards and tools were studied and where appropriate, suggested for responsible organizations to implement. Lithium ion (Li-ion) batteries used for vehicle propulsion power are the assumed battery system of this RP. This chemistry is the prevailing technology associated with high voltage vehicle electrification today and the foreseeable future. The hazards associated with Li-ion battery chemistries are addressed in this RP. Other chemistries and alternative propulsion systems including hydrogen fuel cells are not considered in this version of SAE J2990. Recommendations for hazards associated with hydrogen vehicles can be found in SAE J2990/1.
Hybrid - EV Committee
Impact-Resistant Battery Electrolyte Solidifies When HitTBMG-346336/1/2019
Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged. Inspired by the unusual behavior of some liquids that solidify on impact, researchers have developed a practical and inexpensive way to help prevent these fires.
Graphene Coating Takes Oxygen Out of Lithium Battery FiresTBMG-346016/1/2019
Lithium batteries allow electric vehicles to travel several hundred miles on one charge. Their capacity for energy storage is well known — so is their tendency to occasionally catch on fire. This “thermal runaway” occurs most frequently when the batteries overheat or cycle rapidly.
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
Li-ion Cell CalorimeterTBMG-336181/1/2019
Lithium-ion batteries are an integral part of energy storage systems used in NASA's Exploration program, as well as many modern terrestrial industries. NASA Johnson wanted a better way to measure total and fractional heat response of specific types of Li-ion cells when driven into a thermal runaway condition.
Internal Short Circuit Testing Device to Improve Battery DesignsTBMG-336021/1/2019
Batteries, such as lithium-ion, sold for consumer use in portable electronic devices and other applications such as electrical cars, occasionally fail in the field over time. These cells have typically passed a wide variety of safety tests such as those required by governmental shipping regulations and other certification organizations. Nevertheless, they sometimes fail by overheating, which triggers thermal runaway in the battery. This action may engulf the entire device such as a cellphone or tablet-type devices.
5 Ws of the SAFIRE Lithium-Ion BatteryTBMG-3321111/1/2018
The Safe Impact Resistant Electrolyte (SAFIRE) fire-resistant battery can be used in consumer electronics such as cellphones, in drones and cars, and in soldiers’ packs.
Temperature Rise and Tooth Surface Evolution of Gearbox under Loss of Lubrication: Experimental and Numerical InvestigationF-0074-2018-128645/14/2018
ABSTRACT Loss of the primary lubrication in a helicopter gearbox can result in a very rapid or immediate failure of the transmission system due to drastic reduction in heat removal and the degrading tribological performance of the highly loaded gear contacts. Current methods for predicting the gearbox life and performance under loss-of-lubrication condition are largely experimental and experience-based and thus provide limited insights into the underlying physics of the evolving tribology of gears and bearings. One of the major technical barriers that currently constrain the physics-based predictive capability is the limited understanding and quantitative modeling of the thermomechanical response of tooth surface after the loss of lubrication. The experimental portion of the effort described in this paper is a systematic study of the temperature rise and tooth surface evolution for a generic gearbox under loss-of-lubrication conditions. The overall thermal conditions of the gearbox are monitored through an infrared thermal imaging camera and the transient temperatures at multiple locations of gear and pinions are continuously measured with thermocouples. Tooth samples from different stages towards the final thermal runaway were examined to reveal the underlying physics of the surface evolution and failure after the loss of lubrication. In the modeling effort, FE modeling was combined with the transient thermal mixed-EHL model of gear meshing to simulate the gear thermal response and a sensitivity study was conducted with the validated thermal model to evaluate the potential underlying physics of the thermal runaway. The combined heat generation from frictional sliding and plastic deformation was also determined through the FE simulation of mesoscale sliding contact of tooth surface. The experimental and numerical results suggest that the potential mechanism of the final catastrophic failure is the adiabatic shear instability associated with severe plastic deformation and phase transformation.
Zhang, Huan, Maglieri, John, Sun, Fanping, Wu, Hailing, Chaudhry, Zaffir
Efficient Electro-Thermal Model for Lithium Iron Phosphate Batteries2018-01-04324/3/2018
The development of a comprehensive battery simulator is essential for future improvements in the durability, performance and service life of lithium-ion batteries. Although simulations can never replace actual experimental data, they can still be used to provide valuable insights into the performance of the battery, especially under different operating conditions. In addition, a single-cell model can be easily extended to the pack level and can be used in the optimization of a battery pack. The first step in building a simulator is to create a model that can effectively capture both the voltage response and thermal behavior of the battery. Since these effects are coupled together, creating a robust simulator requires modeling both components. This paper will develop a battery simulator, where the entire battery model will be composed of four smaller submodels: a heat generation model, a thermal model, a battery parameter model and a voltage response model. The paper will provide a brief description on each of these four sub-models and how they are correlated with each other. In addition, this work will examine the significance of accounting for the reversible heat generation term when predicting battery temperature. The obtained comprehensive model will then be validated by testing on a 20 Ah lithium iron phosphate battery. The results show that the electro-thermal model can adequately capture both the voltage and thermal trends in the battery. In addition, the findings indicate that accurate tracking of the curvature present in the temperature profile during discharge/charge can only be accomplished by including the reversible heat generation component in the overall model. These findings are beneficial for battery design and optimization in future applications.
Mathew, Manoj, Mastali, Mehrdad, Catton, John, Samadani, Ehsan, 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
Simulation Helps Samsung Deliver Safer, More Efficient Lithium-Ion Battery PacksTBMG-2770210/1/2017
Siemens PLM Software Plano, TX
Internal Short Circuit (ISC) Device Helps Improve Lithium-Ion Battery DesignTBMG-272197/1/2017
Battery safety is key to the acceptance and penetration of electric vehicles into the marketplace. When battery internal shorts occur, they tend to surface without warning, and usually after the cell has been in use for several months. While some failures simply result in the cell getting very hot, in extreme cases, cells go into thermal runaway, igniting the device in which they are installed. The most publicized failures involved burning laptop and cellphone batteries, and resulted in millions of recalls.
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
Model-Based Adaptive Fault Diagnosis in Lithium Ion Batteries: A Comparison of Linear and Nonlinear Approaches2017-01-11923/28/2017
In this paper, multiple-model adaptive estimation techniques have been successfully applied to fault detection and identification in lithium-ion batteries. The diagnostic performance of a battery depends greatly on the modeling technique used in representing the system and the associated faults under investigation. Here, both linear and non-linear battery modeling techniques are evaluated and the effects of battery model and noise estimation on the over-charge and over-discharge fault diagnosis performance are studied. Based on the experimental data obtained under the same fault scenarios for a single cell, the non-linear model based detection method is found to perform much better in accurately detecting the faults in real time when compared to those using linear model based method.
Sidhu, Amardeep, Izadian, Afshin, Anwar, Sohel
Functional Safety for Battery Monitoring Integrated Circuits2017-01-12023/28/2017
The Battery Monitoring Integrated Circuit (BMIC) is a key technology for Battery Electronics in the electrification of vehicles. Generally speaking, every production hybrid, plug-in hybrid, and battery electric vehicle uses some type of BMIC to monitor the voltage of each lithium battery cell. In order to achieve Functional Safety for the traction battery packs for these electrified vehicles, most designs require higher ASIL ratings for the BMIC such as C or D. For the entire market of available BMIC’s, there is a generic feature set that can be found on almost every IC on the market, such as a front end multiplexer, one or more precision references, one or more Analog to Digital (A/D) converters, a power supply, communications circuits, and window comparators. There is also a fairly consistent suite of self-diagnostics, available on just about every available BMIC, to detect failures and enable achievement of the appropriate ASIL rating. This paper provides a generic approach for the use of these BMICs which is independent of the exact vehicle application and which is applicable to BMIC’s from all vendors. The functional safety concept which can be found in Battery Controller modules across OEMs is explained. Then, the usage of diagnostic features for these BMICs is examined in detail which is the final piece necessary to understand the technical safety requirements for battery pack electronics. Special emphasis is placed on the relationship between the specific diagnostic features which are offered by the silicon suppliers, and the implementation of these technical safety requirements.
Tabatowski-Bush, Ben
Internal Cell Temperature Measurement and Thermal Modeling of Lithium Ion Cells for Automotive Applications by Means of Electrochemical Impedance Spectroscopy2017-01-12153/28/2017
Battery safety is the most critical requirement for the energy storage systems in hybrid and electric vehicles. The allowable battery temperature is limited with respect to the battery chemistry in order to avoid the risk of thermal runaway. Battery temperature monitoring is already implemented in electric vehicles, however only cell surface temperature can be measured at reasonable cost using conventional sensors. The internal cell temperature may exceed the surface temperature significantly at high current due to the finite internal electrical and thermal cell resistance. In this work, a novel approach for internal cell temperature measurement is proposed applying on board impedance spectroscopy. The method considers the temperature coefficient of the complex internal cell impedance. It can be observed by current and voltage measurements as usually performed by standard battery management systems. The relevant frequency range considered for temperature measurements is chosen for high sensitivity and robust behavior and takes state of charge variations as well as aging effects into account. Transient temperature variations caused by various load profiles are analyzed in order to characterize the static and dynamic thermal properties of the cell. The resulting thermal equivalent model describes temperature changes inside the cell dependent on load current and ambient temperature. The temperature measurement approach and the thermal model are suitable for on board implementation in battery management systems. A dedicated battery excitation is not required, as signal components in the relevant frequency range are inherently present in typical driving current profiles. Thereby, significant improvements in terms of on-board diagnostics and battery safety can be achieved without any additional hardware effort.
Haussmann, Peter, Melbert, Joachim
Design of a Calorimeter for Measurement of Heat Generation Rate of Lithium Ion Battery Using Thermoelectric Device2017-01-12133/28/2017
Analysis of thermal behavior of Lithium ion battery is one of crucial issues to ensure a safe and durable operation. Temperature is the physical quantity that is widely used for analysis, but limited for accurate investigations of behavior of heat generation of battery because of sensitivities affected by heat transfer in experiments. Calorimeter available commercially is widely used to measure the heat generation of battery, but does not follow required dynamics because of a relatively large thermal time constant given by cavity and a limited heat transfer capability. In this paper, we proposed a highly dynamic calorimeter that was constructed using two thermoelectric devices (TEMs). For the design of the calorimeter and its calibration, a printed circuit board (PCB) with the same size as the battery was used as a dummy load to generate controlled heat. Dynamics were improved using a lead-lag compensator for temperature control and heat generation was estimated using Kalman filter based on a thermal model of the calorimeter. All parameters were optimized using the PCB. Finally, heat generation rate of a large format of pouch type lithium ion battery was measured and compared with theoretical values.
Yin, Yilin, Zheng, Zhong, Choe, Song-Yul
Standardized Heating Method to Trigger and Prevent Thermal Runaway Propagation in Lithium-Ion BatteriesTBMG-265263/1/2017
Lithium-ion (Li-ion) cells are increasingly used in high-voltage and high-capacity modules. The Li-ion chemistry has the highest energy density of all rechargeable battery chemistries, but associated with that energy is the issue of catastrophic thermal runaway with a fire. With recent incidents in the commercial aerospace and electronics sectors, methods are required to prevent cell-to-cell thermal runaway propagation. The goal of this work was to achieve a common method for triggering a single cell in a Li-ion battery module into thermal runaway, determine if one can consistently obtain this thermal runaway event, and design mitigation measures to address propagation of the thermal runaway to other cells in the module.
Preventing Cell-to-Cell Thermal Runaway in Lithium-Ion Battery ModulesTBMG-2552010/1/2016
Lithium-ion (Li-ion) cells are increasingly used in high-voltage and high-capacity modules. The Li-ion chemistry has the highest energy density of all rechargeable battery chemistries, but associated with that energy is the issue of catastrophic thermal runaway with a fire. With recent incidents in the commercial aerospace and electronics sectors, it was necessary to find methods to prevent cell-to-cell thermal runaway propagation.
3D Imaging Reveals Battery Degradation in Real TimeTBMG-246825/1/2016
Using sophisticated 3D imaging, a team at University College London, The European Synchrotron (ESRF), University of Manchester, Harwell Oxford, Oregon State University, and the National Physical Laboratory visualized a battery’s performance loss and internal structural damage. The images of active commercial Li/MnO2 disposable batteries, captured using X-ray computed tomography, will help to improve cell designs.
Development of the Li-ion Battery Cell for Hybrid Vehicle2016-01-12074/5/2016
Toyota introduced the first generation Prius in 1997. The vehicle was conceived, designed and launched as a dedicated, mass-produced global hybrid vehicle platform, the first of its kind. The introduction of the 2nd and 3rd generation Prius (2003, 2009) saw vehicles with significantly improved performance, including fuel efficiency. The Prius Alpha (Japan/EU), launched in 2011, represented Toyota first foray with Li-ion battery in a strong hybrid configuration. For the Prius Alpha, the adoption of a compact Li-ion battery resulted in sufficient cabin space to allow a 3rd row of seats while maintaining high fuel efficiency. Before and after the launch of the Prius Alpha, an extensive list of tests was performed on the Li-ion battery pack, including electrical, electrochemical, mechanical, and safety. The evaluations were performed in the lab, in the field (demonstration fleets) and by acquiring vehicles used by customers. The MY16 Prius (4th generation) which is launched in 2015, offers a Li-ion battery pack. The array of data available from the Prius Alpha evaluations, were considered in the development of the battery pack for the MY16 Prius. The state of the art battery in the MY16 Prius represents Toyota’s most improved Li-ion battery developed purposefully for strong hybrid traction application. This paper will discuss results from evaluations of Prius Alpha batteries recovered from the market and introduce the technical concept for the state of the art Li-ion battery technology for the MY16 Prius.
Nagai, Hiroki, Morita, Masahiro, Satoh, Koichi
Numerical Investigation of Active and Passive Cooling Systems of a Lithium-Ion Battery Module for Electric Vehicles2016-01-06554/5/2016
In this work, a pseudo three-dimensional coupled thermal-electrochemical model is established to estimate the heat generation and temperature profiles of a lithium ion battery as functions of the state of the discharge. Then, this model is used to investigate the effectiveness of active and passive thermal management systems. The active cooling system utilizes cooling plate and water as the working fluid while the passive cooling system incorporates a phase change material (PCM). The thermal effects of coolant flow rate examined using a computational fluid dynamics model. In the passive cooling system, Paraffin wax used as a heat dissipation source to control battery temperature rise. The effect of module size and battery spacing is studied to find the optimal weight of PCM required. The results show that although the active cooling system has the capability to reduce the peak temperatures, it leads to a large temperature difference over the battery module. On the other hand, the PCM cooling significantly reduces the battery temperature rise and keeps desirable temperature uniformity across the module.
Bahiraei, Farid, Fartaj, Amir, Nazri, Gholm-Abbas
Mechanical Behavior of Lithium-Ion Battery Component Materials and Error Sources Analysis for Test Results2016-01-04004/5/2016
As mechanical damage induced thermal runaway of lithium-ion batteries has become one of the research hotspots, it is quite crucial to understand the mechanical behavior of component materials of lithium battery. This study focuses on the mechanical performance of separators and electrodes under different loading conditions and the error sources analysis for test results. Uniaxial tensile tests were conducted under both quasi-static and dynamic loading conditions. The strain was acquired through the combination of high speed camera and digital image correlation (DIC) method while the force was obtained with a customized load cell. Noticeable anisotropy and strain rate effect were observed for separators. The fracture mode of separators is highly correlated to the microscopic fiber orientation. To demonstrate the correlation microscopic images of separator material were obtained through SEM to match the facture edges of tensile tests at different loading directions. Coated electrode materials show higher fracture strength and higher elongation compared to decoated materials in uniaxial tensile tests. Electrode materials show relatively slight strain rate effect, and no apparent anisotropy was found in their test results. An error analysis program was developed through MATLAB to estimate the standard uncertainty of the results. Input quantities such as initial dimensions of specimen and measured load, fast Fourier transform (FFT) of acquired data and deviation of repeated measurements were taken into consideration as main error sources. Contribution of these sources was evaluated and the results turn out that the low-order magnitude of external force and dimension lead to high level FFT smoothing uncertainty and measurement uncertainty, respectively.
Jiang, Xuqian, Luo, Hailing, Xia, Yong, Zhou, Qing
Charging up electrified POWERTRAINS16OFHP02_032/1/2016
Control technologies race forward while batteries improve and adopt standard sizes. Battery-powered vehicles still represent a small niche in most vehicle markets, but concern over higher fuel prices and tighter emissions regulations continue to spark investments in electrified powertrains. Off-highway developers are looking at technologies and techniques that make electrification more viable. Many of the advances in commercial and industrial vehicles follow the developments of high-volume passenger cars. But system designers note that in off-highway vehicle programs, design teams must consider the vehicle's usage model and design all elements in a holistic fashion.
Costlow, Terry
Electric Vehicle (E-Vehicle) Crash Test Lab Safety GuidelinesJ3040_201512 (Historical)12/17/2015
The special risks associated with conducting crash tests on E-Vehicles can be divided into two main categories; 1) thermal activity inside the battery (resulting from electrical or mechanical abuse) may lead to energetic emission of harmful and/or flammable gases, thermal runaway, and potentially fire, and 2) the risk of electrocution. Procedures to ensure protection from all types of risk must be integrated into the entire crash test process. This informational report is intended to provide guidance in this endeavor using current best practices at the time of this publication. As both battery technology and battery management system technology is in a phase of expansion, the contents of this report must then be gaged against current technology of the time, and updated periodically to retain its applicability and usefulness. The scope of this document is to provide an understanding of the risks and an overview of the techniques established to reduce the likelihood that an event would cause harm to laboratory personnel and/or property. A laboratory considering E-Vehicle crash testing should work closely with the E-Vehicle manufacturer to identify and understand the risks associated with shipping and handling of their vehicle (pre and post-crash), storage of the vehicle (pre and post-crash), battery system diagnostics procedures, and operation of the vehicle.
Impact and Rollover Test Procedures Standards Committee
Consequences of Deep Cycling 24 Volt Battery Strings2015-01-91427/1/2015
Deep charge and discharge cycling of 24 Volt battery strings composed of two 12 Volt VRLA batteries wired in series affects reliability and life expectancy. This is a matter of interest in vehicle power source applications. These cycles include those specific operational cases requiring the delivery of the full storage capacity during discharge. The concern here is related to applications where batteries serve as a primary power source and the energy content is an issue. It is a common practice for deep cycling a 24 volt battery string to simply add the specified limit voltages during charge and discharge for the individual 12 Volt batteries. In reality, the 12 Volt batteries have an inherent capacity variability and are not identical in their performance characteristics. The actual voltages of the individual 12 Volt batteries are not identical. The experimental measurements reveal that one of the two individual batteries in the series configuration is driven to voltages exceeding the acceptable operational limits for a single 12 Volt battery. This condition results in a loss of battery capacity during cycling and results in early string failure because of cell reversals. This condition appears whenever the battery polarization is determined by a single cell rather than being shared by a number of cells that are presumed to be matched.
Catherino, Henry A., Feres, Fred
Fire in Electric Cars2015-01-13824/14/2015
This paper is based on the bachelor thesis “Fire in electric cars” [1] 2013, written in Norwegian. The number of electric vehicles has increased significantly in recent years. Today, there are more than 35,000 electric cars in Norway, and the government's goal is 200,000 cars by 2020. [3] The main question investigated was: What happens when the lithium-ion battery pack ignites? The major part of this assignment was to perform a full-scale fire experiment with a modern and drivable electric car. This experiment took place in February 2013, when a Peugeot iOn 2012 model was set on fire. The car burned out without any attempt being made to extinguish the fire. We had to supply much heat from the external heat source to achieve thermal runaway in the cells. Observations and results from the experiment indicated that fire in the lithium-ion battery cells consists of two phases. During the experiment, there were no high flame pillars and no explosive fire, and the battery cells ventilated one by one.
Schei Blikeng, Lisa, Hegén Agerup, Siril
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