影响MH-Ni电池自放电因素的探讨

探讨了电池中的气氛、ＭＨ电极、隔膜材料、贮氢合金生产工艺和氢化物分解压对ＭＨ－Ｎｉ电池自放电的影响。试验发现隔膜材料对ＭＨ－Ｎｉ电池的自放电影响最大，选用丙烯酸改性的ＰＰ隔膜材料可抑制ＭＨ－Ｎｉ电池的自放电速率。其次是贮氢合金粉的生产工艺，热处理合金粉能提高ＭＨ－Ｎｉ电池的荷电保留，而非热处理合金中Ｍｎ和Ａｌ在高温下溶解于电解液中导致ＭＨ－Ｎｉ电池放电容量不可逆损失。ＭＨ－Ｎｉ电池中的气氛对电池自放电影响较小。在１０１３．２Ｐａ～１０１３２Ｐａ范围内ＭＨ－Ｎｉ电池自放电不受氢化物分解压的影响。贮氢合金中镧含量的提高可改善ＭＨ－Ｎｉ电池荷电保留。负极中添加钴化合物能增加ＭＨ－Ｎｉ电池自放电速率

Study on affecting self discharge factors of Ni MH battery

The effects of atmosphere,MH electrode,production process of hydrogen storage alloys separator materials and decomposition pressure of hydride on the self discharge characteristics of Ni MH battery were studied.It is found that separator materials play an important role in the self discharge of Ni MH ba ttery. A PP separator with grafted acrylic acid groups can obviously improve the charge retention,while PA separator can seriously decrease the charge retention.Mn and Al in hydrogen storage alloy without heat treatment which was dissolved into electrolyte at high temperature caused the irreversible loss of discharge capacity for Ni MH battery.The self discharge of Ni MH battery was not affected by hydride decomposition pressure ranged from 1013.2 Pa to 10132 Pa and atmosphere inside the battery.The charge retention had been improved by increasing content of La content in the hydrogen storage alloy.However,adding cobalt compound to MH electrode can increase self discharge of Ni MH battery.