充电倍率对高功率型磷酸铁锂动力电池循环寿命影响的研究

Study on Cycle Life of LFP High Power Traction Battery Under Different Charge Rate

以高功率型磷酸铁锂动力电池为研究对象,通过开展不同充电倍率的循环寿命试验,验证充电倍率对动力电池循环寿命的影响。通过汇总分析动力电池放电直流内阻、放电功率和放电容量等性能表征参数的变化规律,建立不同充电倍率下动力电池的寿命模型。研究结果表明:样品的放电直流内阻随着循环次数的增加不断增大,充电倍率对增长率和增长幅值均有影响;样品的放电功率随着循环次数的增加不断衰减,充电倍率对衰减率和衰减幅值均有影响;样品的放电容量随循环次数的增加呈明显的二次多项式的衰减趋势,符合公式y=a+bx+cx2。最后,以放电容量为寿命表征参数,构建了不同充电倍率和循环次数的寿命模型。

Taking the LFP batteries for high power application as the research objects,carry out cycle life tests under different charging rate,and verify the influence of the charge rate on the battery cycle life. Via analyzing the important parameters including discharge DC resistance,discharge power and discharge capacity,the battery life model under different charge rates is established. The results showthat the internal resistance of the sample discharge increases with the increase of the number of cycles,and the charge rate has an impact on the growth rate and the growth rate. The discharge power of the sample decays continuously with the increase of the number of cycles,and both the attenuation rate and the amplitude are influenced. The discharge capacity shows a declining tendency of the second order polynomial with the increase of the number of cycles,which accords with the formula y = a ＋ bx ＋ cx^2. Finally,the research group set the discharge capacity as the characterization parameters of battery cycle life and constructed the life model with different charging rates and cycles.