什么是钠电池的挤压测试？

What is the extrusion test for sodium-ion batteries?

挤压测试属于 UN38.3 T5 机械滥用安全试验，模拟仓储堆叠重物挤压、设备受压形变场景，验证电芯受压后是否发生内部热失控。试验设备配备两块平整硬质钢板，将满电电芯水平放置于钢板中间，液压机匀速施压挤压，直至电芯原始厚度压缩 50% 后保持压力 5 分钟。挤压过程极片相互压紧，隔膜被金属毛刺刺破，正负极直接接触发生内部短路放热。全程红外测温记录温升，判定标准：挤压全过程无起火、无爆炸，挤压完成静置观察 1 小时无持续发热。软包电芯铝塑膜易受压破裂漏液，方形铝壳抗压性能更强，但高压下内部活性材料仍会短路；工商业储能大容量电芯必须抽样挤压检测，挤压测试不合格产品堆叠仓储存在批量起火隐患。

Extrusion Test is UN38.3 mechanical abuse safety item T6, simulating heavy stacking pressure during storage and equipment deformation to check thermal runaway after cell compression. Test equipment adopts two flat rigid steel plates, place fully charged cells horizontally between plates, apply uniform hydraulic pressure until cell thickness is reduced by 50% and hold pressure for 5 minutes. Electrodes are tightly compressed during extrusion, separators pierced by metal burrs, and direct cathode-anode contact generates heat from internal short circuits. Infrared temperature recording throughout testing. Pass standard: no fire or explosion during extrusion, no continuous heat generation within 1-hour post-test observation. Aluminum plastic films of soft packs easily crack and leak under pressure, while square aluminum shells have better compression resistance yet internal active materials still short-circuit under high pressure. Large-capacity industrial energy storage cells must undergo extrusion sampling; products failing this test carry mass fire risks during stacked storage.