锂离子电池快速充电的应力调控

STRESS-REGULATED PROTOCOLS FOR FAST CHARGING IN LITHIUM-ION BATTERIES

难以同时实现高充电速度和长循环寿命,已成为当前锂离子电池快速充电技术的主要问题。从快速充电时电池劣化的内在机制入手,以正极活性颗粒扩散诱导应力为抓手,提出了锂离子电池快速充电的应力调控方法:在充电开始后短时间内使活性颗粒的扩散诱导应力迅速达到强度,并在随后充电过程中使扩散诱导应力保持在强度值。进一步地,为解决应力调控充电方案初始无限大电流的问题,提出了包含初始恒流阶段和应力调控阶段的恒流-应力调控充电方案。通过与传统恒流充电、升压充电和指数电流充电方法对比,提出的快速充电应力调控方法能有效实现充电速度、峰值应力和可用容量的最优化平衡。

Inspired by the intrinsic degradation mechanism within the battery during fast charging, a stress-regulation(SR) fast charging method for lithium-ion battery is proposed by considering the diffusion-induced stress in the positive active particles. In the SR protocol, the diffusion-induced stress within the active particle reaches the critical value rapidly in the very early stage of the charging and maintains that value throughout the whole charging process. Furthermore, the constant-current stress-regulation(CCSR) protocol which contains an initial constant current stage and a following stress-regulated stage is proposed to resolve the issue of the theoretically infinite current at the beginning of the SR protocol. Compared with the constant current charging method, the boost charging method and the exponential current charging method, the proposed protocols provide an effective fast charging scheme for balancing the charging speed, the peak stress and the available capacity.