With the rapid development of lithium-ion battery technology in the electric vehicle (EV) industry, the lifetime of the battery cell increases substantially; however, the reliability of the battery pack is still inadequate. Because of the complexity of the battery pack, a reliability design method for a lithium-ion battery pack considering the thermal disequilibrium is proposed in this paper based on cell redundancy. Based on this method, a three-dimensional electric-thermal-flow-coupled model, a stochastic degradation model of cells under field dynamic conditions and a multi-state system reliability model of a battery pack are established. The relationships between the multi-physics coupling model, the degradation model and the system reliability model are first constructed to analyze the reliability of the battery pack and followed by analysis examples with different redundancy strategies. By comparing the reliability of battery packs of different redundant cell numbers and configurations, several conclusions for the redundancy strategy are obtained. More notably, the reliability does not monotonically increase with the number of redundant cells for the thermal disequilibrium effects. In this work, the reliability of a 6 × 5 parallel-series configuration is the optimal system structure. In addition, the effect of the cell arrangement and cooling conditions are investigated.

随着电动汽车（EV）工业中锂离子电池技术的飞速发展，电池的使用寿命大大增加。但是，电池组的可靠性仍然不足。由于电池组的复杂性，本文提出了一种基于电池冗余的考虑热不平衡的锂离子电池组可靠性设计方法。基于此方法，建立了三维电热流耦合模型，场动态条件下电池的随机退化模型和电池组的多状态系统可靠性模型。多物理场耦合模型之间的关系，首先建立退化模型和系统可靠性模型，以分析电池组的可靠性，然后给出具有不同冗余策略的分析示例。通过比较不同冗余单元数量和配置的电池组的可靠性，可以得出有关冗余策略的一些结论。更值得注意的是，可靠性不会随着热不平衡效应的冗余单元的数量而单调增加。在这项工作中，6×5并联系列配置的可靠性是最佳的系统结构。另外，研究了电池布置和冷却条件的影响。获得了有关冗余策略的几个结论。更值得注意的是，可靠性不会随着热不平衡效应的冗余单元的数量而单调增加。在这项工作中，6×5并联系列配置的可靠性是最佳的系统结构。另外，研究了电池布置和冷却条件的影响。获得了有关冗余策略的几个结论。更值得注意的是，可靠性不会随着热不平衡效应的冗余单元的数量而单调增加。在这项工作中，6×5并联系列配置的可靠性是最佳的系统结构。另外，研究了电池布置和冷却条件的影响。