什么是钠电池的高空模拟测试？

What is the altitude simulation test for sodium-ion batteries?

高空模拟是 UN38.3 T1 项目，专门模拟航空运输万米高空低气压环境，验证电芯密封结构、内部承压耐受能力，是空运电池强制准入检测。试验流程：将完整电芯 / 模组 / 密封 PACK 放入可密闭真空高低温舱，舱内气压匀速降至 11.6kPa，对应海拔 15000 米高空环境，恒温 20℃连续静置 4 小时，测试全程实时监控样品温度、电压、外观变化。低压环境下电芯内部气体体积膨胀，若封边焊缝、铝塑膜热封处、防爆阀存在微小缺陷，会出现鼓包、电解液渗漏、极耳氧化短路。测试合格硬性标准：静置全过程无起火爆炸，取出后外观无变形漏液，静置恢复常压后静置 2 小时复测开路电压，电压衰减幅度低于 0.02V，内部无永久性微短路缺陷。软包电芯、方形铝壳、圆柱电池均需分别测试，大容量储能 PACK 需整机入舱验证，用于航空运输的钠电池必须通过本项，未达标产品禁止装机空运，规避高空货仓电池泄漏起火重大航空安全事故。

Altitude Simulation is Item T1 of UN38.3, specially simulating low-pressure conditions at 10,000 meters for air transportation to verify cell sealing and internal pressure resistance, a mandatory test for air shipment access. Test procedure: place intact cells, modules or sealed PACKs in airtight vacuum temperature chambers, reduce air pressure evenly to 11.6kPa (equivalent to 15,000 meters altitude), hold constant 20℃ for 4 hours with real-time monitoring of sample temperature, voltage and appearance. Gas inside cells expands under low pressure; tiny defects on sealing welds, aluminum plastic heat seals or explosion-proof valves cause swelling, electrolyte leakage and tab oxidation short circuits. Rigid pass criteria: no fire or explosion during testing, no deformation or leakage after taking out, open-circuit voltage drop less than 0.02V after 2-hour recovery at normal pressure with no permanent internal micro-shorts. Soft packs, square aluminum and cylindrical cells require separate testing, while large energy PACKs are tested as whole units. Sodium batteries for air transport must pass this item; non-compliant goods are forbidden from aircraft to avoid severe aviation safety accidents caused by battery leakage and fire in cargo holds.