An overdischarge process as a step of battery recycling was investigated using a spent battery. The procedure aims to obtain clean materials while ensuring safety during the disassembly of battery cells. Two overdischarge methods were compared. One method (Method A) overdischarged the DOD to 120 %, reaching −0.431 V. The other method (Method B) was to overdischarged the DOD to 0 V and then maintain the voltage for a day. The cleanness and the structure of the cathodes were analyzed by photographs, SEM, BET, ICP, XPS, and XRD. Sample 1 (S1), overdischarged by the Method A, was contaminated by Cu. In contrast, Sample 2 (S2), overdischarged by the Method B, was contaminant-free. A relatively ordered structure was also confirmed. Method B was implemented using 10-cells connected in series. As soon as the module began to discharge, the voltage of all cells was simultaneously reduced. While the module voltage was held at 0 V, the maximum and minimum cell voltages were 0.064 and 0.033 V, respectively, indicating cell balancing was maintained. Therefore, Method B provides a simple overdischarge process for a battery module or pack without a high-specification discharger.

中文翻译：

---

锂离子电池过放电过程中低损伤正极的恢复

使用废电池研究了作为电池回收步骤的过度放电过程。该程序旨在获得清洁材料，同时确保电池拆卸过程中的安全。比较了两种过放电方法。一种方法（方法A）将DOD过放电至120%，达到-0.431V。另一种方法（方法B）是将DOD过放电至0V，然后维持该电压一天。通过照片、SEM、BET、ICP、XPS 和 XRD 分析阴极的清洁度和结构。通过方法A过度放电的样品1（S1）被Cu污染。相比之下，通过方法B过度放电的样品2(S2)没有污染物。还证实了相对有序的结构。方法 B 使用 10 节串联电池实施。一旦模块开始放电，所有电池的电压就会同时降低。当模块电压保持在 0 V 时，最大和最小电池电压分别为 0.064 和 0.033 V，表明保持了电池平衡。因此，方法B为无需高规格放电器的电池模块或电池组提供了简单的过放电过程。