钠电池内部短路的防护措施有哪些？

What protective measures prevent internal short circuits of sodium-ion batteries?

钠电池内部短路实行全流程防控，覆盖原材料检验、电芯制造、PACK 集成、系统运维全链条，从源头杜绝隐患，同时配套故障预警与阻断装置，短路初期及时切断回路防止热失控。原材料入库防护：隔膜全部做孔隙、抗穿刺全检，剔除存在微孔瑕疵原料；电极铝箔、导电剂严格过滤金属杂质，浆料多重磁除铁设备去除硬质金属颗粒，从原料杜绝穿刺隐患。电芯制造工艺防护：极片裁切、极耳焊接后全自动打磨去除所有金属毛刺，毛刺高度控制在 5 微米以内；叠片 / 卷绕工序增加隔膜缓冲隔离层，边缘预留安全余量，避免极片边缘直接摩擦隔膜；注液、封装车间无尘负压环境，防止金属碎屑混入电芯；化成、分容阶段设置高精度温度、电压阈值，单芯微小温升异常直接筛选报废，提前剔除潜在短路缺陷电芯。电芯材料升级防护：统一采用双面陶瓷涂覆隔膜，大幅提升抗穿刺、热收缩性能，即便出现微小毛刺也难以刺穿隔膜；选用结构稳定硬碳与聚阴离子正极，减少循环粉化碎屑生成，降低游离导电颗粒数量。PACK 集成防护：电芯之间阻燃隔热泡棉缓冲震动挤压，电芯四周限位固定杜绝运输颠簸位移；极耳、汇流排全包裹绝缘高温胶带，金属部件无裸露尖角；每串独立高精度温度传感器，捕捉微短路早期微小温升信号，BMS 立即切断高压回路；电芯排布预留充足散热间隙，控制簇内温差低于 3℃，避免热膨胀挤压隔膜。后期运维防护：每季度巡检电池包压差、单芯温度，压差超 0.05V 及时均衡检修；规范仓储运输，禁止重物堆叠、尖锐物接触电芯；严禁电池长期深度亏电、持续过充运行。多重流程叠加管控，既能大幅降低短路发生概率，即便出现早期微短路，系统可快速识别断电，阻止故障扩大演变为热失控。

Full-process prevention against sodium-ion internal short circuits covers raw material inspection, cell manufacturing, PACK assembly and system maintenance to eliminate root risks, paired with early warning and cut-off devices to stop runaway at initial short-circuit stage. Raw material inspection: full penetration and puncture tests on separators to reject microporous defective products; magnetic filtration removes hard metal impurities from aluminum foil and conductive agents to eliminate puncture risks. Cell manufacturing protection: automatic polishing trims all electrode burrs to below 5 microns after cutting and tab welding; extra separator buffer layers with edge safety margins prevent electrode friction during winding/stacking; dust-free negative-pressure liquid injection workshops block metal debris; precise temperature & voltage thresholds during formation scrap cells with minor abnormal heating to screen latent short risks in advance. Material upgrading: double-sided ceramic coated separators improve puncture and thermal shrink resistance to resist burr penetration; stable hard carbon and polyanionic cathodes reduce pulverized conductive fragments generated over cycles. PACK protection: flame-retardant foam cushions absorb vibration and squeeze with fixed cell frames to avoid shifting during transportation; high-temperature insulating tape fully wraps exposed metal tabs and busbars. Independent high-precision temperature sensors capture early micro heating signals from minor shorts for immediate BMS high-voltage cut-off. Sufficient cooling gaps limit cluster temperature difference below 3℃ to avoid separator squeeze from thermal expansion. Maintenance protection: quarterly inspections of string voltage difference and cell temperature, with equalization for deviation over 0.05V; standardized transportation forbids heavy stacking and sharp contact; prohibit long-term deep discharge and continuous overcharge. Coordinated full-chain control drastically cuts short-circuit probability and enables rapid power-off upon early micro short to avoid escalation into thermal runaway.