钠电池 PACK 的加热膜有什么作用？

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

加热膜贴合电芯壳体或水冷板，是低温热管理核心部件，针对性弥补钠电池低温性能短板。第一低温容量恢复：环境 0℃以下电解液粘度飙升，离子电导率暴跌，放电容量仅剩六成；加热膜升温至 10℃以上，容量恢复 90% 以上，北方冬季储能、冷链车不可或缺。第二低温充电防护：零下环境充电极易负极析出金属钠刺穿隔膜，加热膜预热至安全区间后 BMS 才允许充电，从源头杜绝短路起火隐患。第三消除 PACK 内部凝露：低温高湿环境壳体内易凝结水珠，加热膜维持包内温度高于露点，避免凝露腐蚀线路、降低绝缘电阻。配套温控开关，达到设定温度自动断电干烧保护，适配所有户外、北方低温 PACK，搭配风冷 / 水冷协同实现全季节稳定温控，大幅拓宽设备全年运行温度区间。

Heating films are attached to cell shells or water cooling plates, acting as core low-temperature thermal management components to targetedly make up for the low-temperature performance defects of sodium-ion batteries. First low-temperature capacity recovery: electrolyte viscosity surges below 0℃ with sharply fallen ionic conductivity, leaving only 60% discharge capacity. Heating films raise temperature above 10℃ to restore over 90% capacity, indispensable for northern winter energy storage and cold-chain vehicles. Second low-temperature charging protection: charging under sub-zero environment easily precipitates metallic sodium on anodes to pierce separators. BMS only allows charging after heating films preheat cells to safe ranges, eliminating short-circuit fire risks from the source. Third eliminate internal PACK condensation: water beads easily condense inside shells under low-temperature & high-humidity environments. Heating films maintain internal temperature above dew point to avoid circuit corrosion and insulation resistance decline caused by condensation. Equipped with temperature control switches to automatically cut off power for dry burning protection after reaching set temperature, heating films adapt to all outdoor and northern low-temperature PACKs, cooperating with air/water cooling to realize stable full-season temperature control and greatly widen the annual operating temperature range of equipment.