Abstract: Taking 280 Ah square lithium iron phosphate battery as the research object, this paper designed a variable section symmetrical flow channel liquid cooling plate to conform the heat generation characteristics of the large-capacity battery pack, established a liquid cooling simulation model of lithium-ion battery pack, and adopted a reversible liquid cooling method. The cooling effect of the battery pack under different cooling methods, the influence of the inlet temperature of the coolant and the turning time of the reversible cycle on the heat dissipation performance of the battery pack were studied. The results show that the symmetrical flow channel with variable cross section can improve the heat dissipation performance of the battery located in the center of the battery pack, so as to balance the temperature inconsistency caused by different positions. The bidirectional reversible circulation mode reduces the maximum surface temperature of the battery pack by 17.8 ℃ compared with the condition of only natural convection. In addition, in the proposed liquid-cooled plate structure, the inlet temperature of the coolant mainly affects the maximum temperature of the battery pack surface, and the turning time of the reversible cycle mainly affects the temperature uniformity of the battery pack.

Key words: lithium-ion battery thermal management, liquid cooling plate, direction control, reversible circulation liquid cooling