Smart Control Logic of Battery Cooling System for Electric Vehicles (EVs)

Transport sector comes under largest energy consuming category, after mining and other industries, a significant fuel economy improvement are required to reduce green house emission. Till now the most promising technologies in this attempt are electric vehicle. Electric vehicles use large batteries to store energy, most common battery used in electric vehicles are lithium ion and lithium polymer preferred due to their high energy density compared to weight.The flow of current causes heating in the battery cells, performance of Lithium-Ion battery cells is greatly impacted by their temperature. For optimum performance it should operate in desired temperature range ( 15°C-35°C).Battery cooling system is the system which maintain optimum temperature of battery by cooling/heating to increases the thermal efficiency of vehicle. Most common Battery Thermal Management methods used today are, Air Cooled , Indirect liquid Cooled and Direct Cooled. In choosing a cooling method for battery system, there is lot of gap found considering various factor such as cooling performance, temperature uniformity, weight, complexity and cost. When all cooling method are compared Indirect liquid cooling is found to be more efficient. To achieve above performance an “INTELLIGENT STATE OF ART CONTROL SYSTEM IS DESIGNED “.Which take into account the heat transfer need of battery pack and operate the major component at optimum power so that thermal transfer need is accomplished, with minimum possible energy taken from battery itself. Challenges were to select major component of battery cooling system, so to have an efficient system all together and operate these part at optimum power. To achieve this an unique algorithm was written which closely monitor all conditions with help of various temperature sensor and pressure switches and generate pulse width modulation signal with different duty cycle to attend different thermal transfer need of battery pack.