Research On Cold Plate Structure Of Automotive Lithium Battery Based On CFD

With the severe situation of energy shortage and environmental pollution,new energy vehicles(NEVs),led by electric vehicles(HV),have become the focus of attention because of their low emission.Battery pack is the main power source of electric vehicle(EV).Because of the sensitivity of the battery to temperature,the research on the heating problem of the battery pack is a hot spot.In high discharge rate and high temperature environment conditions,the battery pack will produce a lot of heat.Once the temperature is too high,there may be thermal runaway failure,which affects the safety of electric vehicle(EV).The heating will decrease Low temperature uniformity of battery pack affects the service life of battery pack.Therefore,it is of great significance to study an efficient battery thermal management and cooling system and effectively control the working environment temperature of the battery pack.Aiming at the problem that the safety of the battery pack is affected by the high maximum temperature,the theory of thermal characteristics of lithium battery and the calculation method of thermophysical material parameters are studied,the experimental platform is built to test the internal resistance and heating characteristics of the battery cell,the relationship between the internal resistance and SOC is fitted,and UDF program is compiled.The heat generation model of the battery cell is established,and the heat flow field of the battery cell is simulated by fluent,which verifies the accuracy of the model.The cooling effect of scheme C is the best,and it is further verified that the longitudinal arrangement can effectively control the temperature of the battery pack under different discharge rate and different ambient temperature conditions;the influence of the number of cold plates on the heat dissipation of the battery pack is studied,and it is concluded that the number of five cold plates leads to the low efficiency of the coolant taking away heat,and the longitudinal arrangement of one cold plate is the most effective Reasonable number of cold plates.Three schemes of coolant flow direction and three kinds of microchannel structures are proposed to study the influence of coolant flow direction and microchannel structure on the comprehensive performance of cold plate.In terms of thermal performance,the maximum temperature of battery pack in scheme C is 0.72 ? lower than that in scheme a,and the maximum temperature of cold plate is 0.57 ? lower than that in scheme A.when scheme C is applied to three kinds of microchannel structures of a,B and C,the heat dissipation efficiency is increased by 2.7%,2.7% and0.5% respectively In hydraulic performance,structure B is due to structure a and structure C.The UDF heat source program obtained by setting up the experimental platform and sorting out the data shows that the simulation temperature of the heat generation model of the battery unit is consistent with the experimental temperature,and the accuracy is high;the heat dissipation model of the liquid cooled battery pack is established,and the longitudinal arrangement can effectively control the maximum temperature of the battery pack;when the number of cold plates is different in the longitudinal arrangement,theoretically,the increase of the number o f cold plates can reduce the maximum temperature of the battery pack Considering the energy management strategy,the comprehensive heat transfer efficiency of the five cold plates is not high,and the layout scheme of one cold plate in the longitudinal direction is the most reasonable scheme;the proposed three kinds of coolant flow direction,the flow direction scheme with small circulation is the best scheme,which can improve the temperature uniformity of the battery pack.The coolant flow direction scheme combined with the B microchannel structure can effectively improve the comprehensive performance of the coldplate.