钠电池 PACK 的保险丝有什么作用？

What are the functions of fuses for sodium-ion battery PACK?

高压保险丝串联 PACK 总高压主回路，是硬件终极过流防护器件，与 BMS 软件保护形成双重安全屏障。当外部线路短路、接线错误、电芯内部短路产生超大故障电流时，保险丝毫秒级熔断，彻底切断高压回路，阻断持续大电流放热引发的电芯起火爆炸。保险丝额定熔断电流根据 PACK 峰值充放电电流匹配，预留安全冗余，正常 0.2C~1C 平稳充放电全程不会熔断，仅故障大电流工况触发断开。分为慢熔、快熔两类：工商业储能平稳充放电场景选用慢熔保险丝，过滤瞬时冲击电流避免误断；叉车、观光车瞬时大功率输出设备配套快熔型，短路瞬间即刻断路。保险丝装配于高压汇流盒内部，外层加隔热绝缘护套，防止熔断火花引燃周边线束，是 PACK 不可缺少的被动安全硬件。

High-voltage fuses are connected in series to the main high-voltage loop of PACK, serving as the ultimate hardware overcurrent protection device and forming a dual safety barrier with BMS software protection. When external line short circuits, wrong wiring or internal cell short circuits generate excessive fault current, fuses blow within milliseconds to completely cut off the high-voltage loop and block cell fire and explosion caused by continuous large-current heat release. The rated blowout current of fuses is matched with PACK peak charge-discharge current with safety margin reserved, which will not blow during normal stable 0.2C~1C charging and discharging, and only trigger disconnection under fault large-current conditions. Fuses are divided into slow-blow and fast-blow types: slow-blow fuses are adopted for industrial & commercial energy storage with stable charging and discharging to filter instantaneous impact current and avoid false disconnection; fast-blow fuses are matched for forklifts and sightseeing vehicles with instantaneous high-power output to break the circuit instantly upon short circuit. Fuses are assembled inside high-voltage junction boxes with outer heat insulation and insulating sheaths to prevent blown sparks from igniting surrounding harnesses, acting as indispensable passive safety hardware for PACK.