什么是钠电池的针刺测试？

What is the nail penetration test for sodium-ion batteries?

针刺测试为 UN38.3 T7 极端安全测试，模拟金属尖锐物刺穿电芯的危险工况，检验内部短路放热控制能力。试验采用直径 3mm 硬质钢钉，匀速垂直刺穿满电电芯正负极活性材料区域，钢钉全程停留贯穿电芯 1 小时，连续拍摄温度、外观变化。钢钉导通正负极形成永久内部短路，局部持续放热，劣质电池会快速冒烟燃烧。合格标准：针刺后仅局部轻微升温，无明火、无剧烈爆炸，1 小时观察期内无持续放热、电解液无大量喷射泄漏。普鲁士蓝类钠电池针刺热释放高于聚阴离子体系，针刺测试是储能电池入库前强制安全抽检项目，户外设备、船舶用钠电池针刺性能不达标严禁批量投产。

Nail Penetration Test is UN38.3 extreme safety Item T7, simulating hazards of sharp metal piercing cells to evaluate heat control after internal short circuits. A 3mm hard steel nail vertically pierces the active area of fully charged cells at constant speed and remains penetrating for 1 hour, with continuous recording of temperature and appearance changes. The steel nail connects cathode and anode to form permanent internal short circuits with continuous local heat generation; inferior batteries rapidly smoke and burn. Pass criteria: only mild local temperature rise after penetration, no open flame or violent explosion, no continuous heat generation and no massive electrolyte spray within the 1-hour observation window. Prussian blue sodium batteries release more heat after penetration than polyanion systems. Nail penetration is a mandatory safety sampling inspection before energy storage cell warehousing. Sodium batteries for outdoor and marine equipment failing this test are prohibited from mass production.