磷酸铁锂电池性能衰退与容量预测模型研究

Research on performance decline characteristic and available capacity prediction model of lithium-ion battery

动力电池由于老化导致的性能衰退与储能系统功率吞吐能力密切相关。为了揭示磷酸铁锂电池的老化特性,进行了实验研究。通过不同恒定倍率下的循环老化实验和特性实验,获取了磷酸铁锂电池特征参数的变化规律以及容量增量分析(ICA)曲线的变化趋势。实验结果表明,磷酸铁锂电池的容量和欧姆内阻随老化变化明显。利用半经验老化模型结合2 C循环老化实验结果验证了电池可用容量预测结果,预测模型能够有效地预测电池可用容量衰减,预测误差在2%以内。

The performance decline caused by aging is closely related to the power throughput of energy storage systems. In order to reveal the aging characteristics of lithium iron phosphate battery, the experimental study was carried out. A series of cycle aging tests under different current rates, as well as characteristic tests are taken to investigate battery characteristic parameters during cycling. Also, ICA(Incremental capacity analysis) is conducted to discuss the aging mechanism. A capacity prediction estimation model is used to estimate battery capacity during constant current cycling. The experimental results show that battery capacity decreases with aging, and ohmic resistance increases more obvious comparing with polarization resistance. The capacity prediction model could estimate capacity loss efficiently and the prediction error is less than 2%.