| Lithium-ion batteries have become the current main power source of electric vehicles,and their performance and service life are sensitive to operating temperature.Generally,the recommended operating temperature is between 15℃～35℃.In this paper,part of the research on the heat dissipation of cylindrical lithium-ion batteries is carried out.The main contents are as follows:(1)The shape of the batteries used in electric vehicles both here and abroad,and the corresponding active cooling methods were investigated.The 18650 lithium-ion battery packs were selected to be the research object.The internal resistance and heat generation of the lithium-ion battery pack,as well as the temperature under different discharge rates,were measured by HPPC(Hybrid Pulse Power Characterization).The test results show that the 3C discharge rate battery pack can reach up to 68℃,which is much higher than the recommended temperature and needs to be cooled urgently.(2)A micro-bare-tube liquid cooling plate was designed and processed,and was bend and attached to the side of the cylindrical battery,then a test system was built.The test results showed that at 3C discharge rate,with 0.12L/min coolant flow rate,the maximum temperature of battery pack can be controlled at 36℃.(3)FLUENT was used for modeling and simulation,and the validity of the model was verified by experimental data.Based on this,the liquid-cooled plate with unidirectional flow was changed to bidirectional flow.The simulation results showed that,also at 3 C discharge rate,only 0.002L/min flow rate can stabilize the maximum temperature of the battery pack within 35℃.And the pressure drop in this tube is reduced from 41297Pa to 4785.5Pa.Further,the influence of different coolant inlet temperatures and flow rates on the maximum temperature of the battery was obtained. |
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