什么是钠电池的过充测试？

What is the overcharge test for sodium-ion batteries?

过充测试不属于 UN38.3 八项强制项，但属于储能、车载电池国标强制安全试验，模拟 BMS 失效、充电器失控持续过充风险。将标准满电电芯持续以 0.2C 倍率过充至额定电压 1.25 倍，连续充电 5 小时，全程监测温升、产气、外观变化。持续过充会导致正极钠离子过度脱嵌，晶格崩塌，电解液大量分解产气，电芯内部压力急剧上升，极易鼓包爆炸。合格标准：过充过程无明火、不爆炸，电芯最高温度低于 145℃，静置观察 2 小时无持续放热、无电解液喷射。聚阴离子正极热稳定性优势在过充测试中充分体现，过充产气远少于普鲁士蓝与层状氧化物；工商业大容量储能 PACK 出厂前必须抽样过充检测，防止电控故障引发电站火灾。

Overcharge Test is not among the eight mandatory UN38.3 items but a compulsory national safety test for energy storage and vehicle batteries, simulating risks of continuous overcharge from failed BMS and uncontrolled chargers. Continuously overcharge fully rated cells at 0.2C to 125% of nominal voltage for 5 hours with full monitoring of temperature rise, gas generation and appearance. Sustained overcharge causes excessive sodium deintercalation, cathode lattice collapse and massive electrolyte decomposition gas, sharply raising internal cell pressure and triggering swelling & explosion risks. Pass criteria: no open flame or explosion during overcharging, peak cell temperature below 145℃, no continuous heat generation or electrolyte spray within 2-hour observation window. Polyanion cathodes display prominent thermal stability advantages with far less gas generation than Prussian blue and layered oxides. Large-capacity industrial energy storage PACKs require overcharge sampling inspection before factory delivery to avoid power station fires caused by control failure.