什么是钠电池的外部短路测试？

What is the external short-circuit test for sodium-ion batteries?

外部短路测试为 UN38.3 T5 电气安全项目，模拟运输、使用时正负极意外搭接短路极端工况，验证电池热失控安全冗余。试验流程：电芯满电 SOC100%，环境恒温 20℃，用总电阻 0.1Ω 的铜导线直接连接正负极，持续短路 1 小时，全程采集表面温度曲线。短路瞬间超大电流产生大量焦耳热，极易引燃电解液发生燃烧。合格判定：测试过程电芯表面最高温度不超过 130℃，测试全程不起火、不爆炸，测试结束静置 24 小时后电芯无持续自发热、容量无永久性大幅衰减。聚阴离子钠电池热稳定性更优，短路温升远低于普鲁士蓝体系；大容量 PACK 除单电芯抽样外还需模组级短路验证，储能电站电池若外部短路极易引发整柜连锁热失控，该项是安全核心筛查项目。

External Short Circuit Test is UN38.3 Item T5 for electrical safety, simulating extreme positive-negative accidental short circuits during transportation and operation to verify thermal runaway safety margin. Test procedure: fully charged cells (SOC 100%) at constant 20℃ ambient temperature, connect positive and negative terminals directly via 0.1Ω total copper wire for continuous 1-hour short circuit, collect full surface temperature curves. Instant excessive current generates massive Joule heat and easily ignites electrolyte. Pass criteria: peak cell surface temperature below 130℃ throughout the test, no fire or explosion; no continuous self-heating and no permanent severe capacity fading after 24-hour post-test standing. Polyanion sodium batteries possess superior thermal stability with much lower temperature rise than Prussian blue systems. Besides single-cell sampling, large-capacity PACKs require module-level short-circuit verification. External short circuits of energy storage batteries easily trigger cabinet-wide chain thermal runaway, making this a core safety screening item.