钠电池隔膜的作用是什么？

What is the function of the separator of Sodium-ion Battery?    

隔膜是钠离子电池的安全防护核心部件，为多孔高分子薄膜材料，兼具隔离与导通双重功能。其一，物理隔离作用：严格分隔电池正极与负极，避免正负极直接接触，从根源杜绝电池内部短路、打火、热失控等安全隐患；其二，离子导通作用：隔膜表面布满微米级微孔结构，仅允许电解液中的钠离子自由穿梭通过，阻挡电子、杂质颗粒穿透，保障离子循环回路正常运行。隔膜的孔径大小、孔隙率、厚度、耐高温性、抗穿刺性，直接决定电池的安全等级，是钠电池极端工况下稳定运行的重要保障。

The separator is the core safety protection component of Sodium-ion Battery, which is a porous polymer film material with both isolation and conduction functions. First, physical isolation function: it strictly separates the cathode and anode of the battery, avoids direct contact between the cathode and anode, and fundamentally eliminates the safety hazards such as internal short circuit, ignition and thermal runaway of the battery; second, ion conduction function: the separator surface is covered with micron-scale micropore structures, which only allow sodium ions in the electrolyte to shuttle through freely, and block the penetration of electrons and impurity particles, ensuring the normal operation of the ion circulation circuit. The pore size, porosity, thickness, high temperature resistance and puncture resistance of the separator directly determine the safety level of the battery, and are an important guarantee for the stable operation of the sodium battery under extreme working conditions.