VRLA电池的AGM隔板和氧传输(1)

AGM separator and oxygen transfer in VRLA battery(Ⅰ)

VRLA电池实现了内部氧循环,电池可以密闭。充电时,正极产生的氧能通过具有良好传输性能的AGM隔板到达负极,与活性物质发生反应,被还原成水,这过程被称为氧再化合作用或密闭氧循环过程。这个反应过程,要求AGM隔板有良好的孔隙结构和高的孔隙率;AGM隔板的孔隙与负极活性物质的孔隙应当互相匹配;AGM隔板要有良好的耐酸性和弹性等。氧在AGM隔板中的传输速度不但与隔板的孔结构有关,还与隔板中电解液的饱和度有关。电解液的饱和度高时,氧的传输速度低;电解液的饱和度在60%左右时,氧的传输接近在气相中扩散的情况。在AGM隔板中添加适量憎水合成的玻璃纤维,可以增加隔板强度和电池的注酸量。

Owing to realizing interior oxygen cycling, the VRLA battery could work effectively in sealed state. The oxygen (coming) from positive electrode through AGM to negative electrode reacted with the lead electrode and was reduced to water under charging, the process was called oxygen recombination or closed oxygen cycling. AGM separator should have good pore structure, high porosity and enough electrolyte saturation. The pore structure of AGM should match with that of negative active material. AGM should be acid-proof and elastic. The transfer rate of oxygen through the AGM separator related to the electrolyte saturation closely, in addition to the pore structure of AGM. When the electrolyte saturation in the AGM was high, the transfer rate of (oxygen) would be low. When the electrolyte saturation in the AGM was low to about 60%, the transfer rate of oxygen would be close to the situation of diffusion in air. If adding a right amount of synthesized fiber to AGM, the strength of AGM separator would increase, and the filling amount of electrolyte in VRLA battery could increase too.