磷酸铁锂锂离子电池电芯注液量相关试验验证与探讨

Experimental verification and discussion on electrolyte injection quantity of LFP lithium-ion battery

通过详细的理论计算,推导出LFP/230 Ah锂离子电池电芯孔隙率和极限饱和吸液量,并且通过试验设计进行验证。通过调整LFP/230 Ah锂离子电池电芯的一次注液量与不同高温下的静置时间来验证随后高温负压化成后电芯各项电性能参数受到的影响。测试及验证结果表明:随着一次注液后高温静置时间的延长,LFP/230 Ah锂离子电池电芯中游离态电解液量逐渐减少,而且在24 h后基本达到稳定状态;一次注液后随着高温静置时间的延长,电芯在化成过程中的温度逐渐降低,而且化成结束后的开路电压越来越高,分容容量有升高趋势,DCR有降低趋势,电芯满充后黑斑析锂位置点的数量减少,而且黑斑面积也逐渐缩小,但在SoC为0.6%下的K值筛选没有受到显著影响。

Firstly,through detailed theoretical calculation,the porosity and limit saturation liquid absorption of LFP/230 Ah lithium-ion battery cell were derived and verified by experimental design.Finally,by adjusting the LFP/230 Ah electrolyte injection volume and different high temperature standing time to verify the influence on the subsequent high temperature negative pressure formation of the battery cell electrical performance test parameters.With the extension of high temperature standing time after electrolyte injection,the amount of free electrolyte in LFP/230 Ah lithium-ion battery cell gradually decreased,and basically reached stable state after 24 h.With the extension of high temperature standing time after a liquid injection,the temperature of the cell in the formation process gradually decreased,and the open circuit voltage after the formation was also higher,the capacity tends to increase,and the DCR tends to decrease.After the cell was fully charged,the number of black spot lithium locations and the black spot area also gradually shrinked,but it had almost no significant effect on the K value screening at 0.6%SoC.