基于锂电池退化模型的混合动力最优控制

Optimal Control Strategy for Hybrid Electric System Based on Lithium Battery Degradation Model

提出一种基于燃料消耗量和燃料电池/锂电池退化机制的混合动力系统最优控制策略。该模型基于瞬态功率负载、启动/停止循环、空转和大功率导致的性能损失等因素,为燃料电池电化学表面积(ECSA)的衰减提供了分析解决方案。利用简化的电化学模型对燃料电池退化机制进行量化,利用经验模型将锂电池容量衰减和放电倍率(C-rate)进行函数关联。实验结果表明,基于不同权参数α值的燃料电池组功率负荷曲线发生显著变化,影响其寿命性能。权参数α越小,燃料电池组的负载跟随曲线越陡,权参数α越大,功率负载跟随曲线越平滑。

A optimal control strategy for hybrid electric system which concurrently accounts for fuel consumption as well as fuel cell and lithium battery degradation model is introduced. The model is based on the factors of transient power load, start/stop cycle, idle and performance loss caused by high power. An analytical solution is provided for the decay of electrochemical surface area(ECSA) of fuel cells. The degradation mechanism of fuel cells is quantified by using simplified electrochemical model. A validated empirical model is used to correlate capacity attenuationand discharge rate of lithium battery. The experimental results demonstrate that the power load curve of fuel cell stack based on different weight parameter α changes significantly, which affects its life performance.The smaller the value of α is, the steeper the load following curve of fuel cell stack is. The greater the value of α is, the smoother the power load following curve is.