Effect of temperature on the high-rate pulse charging of lithium-ion batteries

Based on the residual energy recovery in the electromagnetic emission scenario, the 30C pulse charging cycle experiments of LiFePO4 batteries customized for electromagnetic emission at different charging temperatures were carried out to study the influence of charging temperature on battery aging. By adjusting the ambient temperature, heat dissipation conditions, and rest time, we studied the battery aging process at the average charging temperatures of 16 degrees C, 21 degrees C, 26 degrees C, 30 degrees C and 35 degrees C. Experimental results show that increasing charging temperature can significantly delay battery aging and prolong battery cycle life. In addition, when the average charging temperature is lower than 30 degrees C, the battery shows nonlinear aging; when the average charging temperature is higher than 30 degrees C, the battery shows linear aging in the early stage of cycling and nonlinear aging at the end of the cycle. The results of differential capacity analysis (DCA) show that the loss of lithium inventory is the primary aging mode of the battery and did not change with charging temperature. The aging mechanism of the battery under high-rate pulse charging was studied through multiscale post-test analysis. Analysis results showed that with the increase of charging temperature, the area of lithium-plating area decreases, and the thickness of SEI film increases. It can be inferred that when the average charging temperature is lower than 30 degrees C, lithium plating is the primary aging mechanism of the LiFePO4 battery customized for electromagnetic emission. When the average charging temperature is higher than 30 degrees C, the growth of SEI film is the primary aging mechanism of the battery.