The rapidly expanding lithium-ion battery (LIB) market has heightened the demand for efficient diagnostics for in-use cells and the reliable grading of used cells. Various purpose-built analysis tools and statistical algorithms have been developed, but often rely on redundant instrumentation and computationally intensive procedures. Here, we propose using the variance of the capacity difference between 0.2C and 1C, Var(Δ Q 0.2C-1C (V) ), based on the strong correlation between the interfacial state of the anode and mode of capacity degradation, as a measure of the health state of individual cells. A single-point “off-board” measurement of Var(Δ Q 0.2C-1C (V) ) indicates whether a particular cell is experiencing self-limiting or accelerating degradation and is thus near a knee point in its cycle life. This assessment additionally provides a quantitative criterion for differentiating used cells for reuse or recycling. Our findings suggest that utilizing state-of-charge-dependent key electrochemical properties enables the cell health to be accurately monitored, thereby promoting sustainability in the expanding battery market.

中文翻译：

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使用充电状态相关参数检测锂离子电池退化的拐点

快速扩张的锂离子电池 （LIB） 市场增加了对在用电池的高效诊断和对废旧电池的可靠分级的需求。已经开发了各种专门构建的分析工具和统计算法，但通常依赖于冗余的插桩和计算密集型程序。在这里，我们建议使用 0.2C 和 1C 之间容量差异的方差 Var（Δ Q 0.2C-1C （V） ），基于阳极界面状态与容量退化模式之间的强相关性，作为单个电池健康状况的量度。Var（Δ Q 0.2C-1C （V） ） 的单点“板外”测量表明特定电池是否正在经历自限性或加速降解，因此接近其循环寿命的拐点。该评估还为区分使用过的细胞以进行再利用或回收提供了定量标准。我们的研究结果表明，利用依赖于电荷状态的关键电化学特性可以准确监测电池健康状况，从而促进不断扩大的电池市场的可持续性。