什么是钠电池的强制放电测试？

What is the forced discharge test for sodium-ion batteries?

强制放电是 UN38.3 T8 电气滥用测试，模拟电池接线错误、电控故障造成深度过放的极端场景，评估过放后热安全表现。满电电芯外接标准固定负载电阻，持续强制放电至电压归零并保持放电 90 分钟，实时监测外壳温度变化。深度过放会破坏负极 SEI 膜，钠离子不可逆大量析出，内部副反应持续放热，存在鼓包起火风险。测试合格判定：全程无燃烧爆炸，电芯最高表面温度不超过 140℃，测试结束静置 1 小时无复发热现象，拆解内部无大面积活性材料粉化、隔膜腐蚀破损。深度过放会永久损耗电芯容量，强制放电不合格电池使用中一旦出现电控故障极易报废甚至起火，低速电动车备电电池必须完成本项检测。

Forced Discharge Test is UN38.3 electrical abuse Item T8, simulating extreme deep over-discharge caused by wrong wiring and electronic control failure to evaluate thermal safety after over-discharge. Connect fully charged cells to standard fixed load resistance, continuously force discharge down to zero voltage and hold discharge for 90 minutes with real-time shell temperature monitoring. Deep over-discharge destroys anode SEI films, triggers massive irreversible sodium precipitation and continuous heat from internal side reactions with swelling and fire risks. Pass criteria: no combustion or explosion throughout testing, peak cell surface temperature below 140℃, no reheating within 1-hour post-test standing, and no large-area active material powdering or corroded separators after disassembly. Deep over-discharge permanently damages cell capacity. Batteries failing forced discharge easily fail or catch fire once control faults occur during operation, and backup batteries for low-speed vehicles must complete this test.