The Research And Simulation Analysis Of Heat Dissipation With Liquid Cooling For The Power Battery Pack Of Pure Electric Vehicles

The major obstacles to designing a scaled-up of Li-ion batteries for EV applications have been safety,performapce and overall cell life.The safety issue concerns the thermal runawsy of battery cell,and the prediction and prevention of the propagation of thermal runaway have been studied by many researchers.A Li-ion cell generates heat during both charge and discharge,and the heat generation in the battery can increase sharply leading to overbeating under stressful conditions such as high power draw and high ambient tempenture while overheating can also be caused by defects in individual cells.If the cells are not thermally managed,the thermal runaway propagates into an entire battery pack.Various battery thermal management systems have been developed for air-and liquid-cooling to precent the thermal run away propagation without over-designing the cooling system,The bettery cell temperature also affects the performance,reliability and lifespan.High battery cell temperature can cause a shortening of the lifespan of the Li-ion battery due to increased degradation of the battery cell.It was found that every degree of cell temperature rise reduces the lifespan of the Li-ion battery by approximately two months in an operating temperature range of 30?40?.To achieve a full lifespan,the cell temperature difference should be kept below 5 ? as large temperature non-uniformity in the battery pack affects adversely overall cell lifespan as well as available cell capacity.Therefore,a battery thermal management system enabling effective temperature control becomes essential for safety,performance,reliability and overall cell life,For better design of thermal management system,understanding the real time behaviour of Lion cells in vehicle operating conditions is critical,and modelling its thermal behaviour in various EV drive cycles can help to design such battery thermal management systems.they presented theoretical and computational comparison of the cooling effectiveness of a battery pack using different coolants,air,mineral oil and water/glycol.The advantages and disadvantages of the air cooling system as compared to direct-contact liquid cooling were identified.More recently,it was shown numerically that the use of are ciprocating air flow is able to improve temperature uniformity of a lithium-ion battery pack.Due to the simplicity of an air cooling system,it is highly preferred in many applications.In the framework of forced-air cooling,however,there is a lack of detailed parametric studies in the literature to systematically consider the effects of geometric parameters and blower power on cooling effectiveness.