MH-Ni电池高倍率循环寿命影响因素探讨  

Discussing of invalidation factors of Ni-MH battery at high charge and discharge rate

作　　者：陈永辉[1] 魏进平[1] 高峰[1] 周伟 张允什[1] 周作祥[1] 

机构地区：[1]南开大学新能源材料化学研究所,天津300071

出　　处：《电源技术》2001年第B05期142-145,共4页Chinese Journal of Power Sources

基　　金：国家自然科学基金资助项目! (59776 0 38)

摘　　要：D型MH Ni电池 1C率 10 0 %DOD放电 30 3周期后 ,电池放电容量降低 2 9.9% ,电池的内阻增大 15 5 % ,放电 30min时电池端电压降低 8.4%。对循环前后电池进行对比实验 ,发现循环后电池放电至 1.0V时 ,其负极的电极电位降低为 -75 0mV(vs .HgO/Hg电极 ) ,而未循环的为 -85 4mV (vs .HgO/Hg电极 ) ;P C T实验结果表明 ,循环后电池中的合金电化学容量只有 12 9.4mAh/g ,而未循环的为 2 79.7mAh/g ,这两者说明电池循环后负极中的合金贮氢能力已大大下降。通过对循环前后电池正、负极活性物质的扫描电镜实验、粒度分布测试及X射线衍射实验等进行分析 ,证实电池经循环后失效的主要原因是因为负极活性物质的腐蚀、粉化和氧化。Properties of D size Ni-MH batteries were investigated after 303 charge-discharge cycles of 100% DOD at 1 C rate.The results show that the decay of discharge capacity and discharge voltage at 30 minutes is 29.9% and 8.4% respectively, but the resistance has increased 155%.The voltage of negative electrode was -750 mV vs.HgO/Hg reference electrode in 303 cycles and -854 mV vs.HgO/Hg reference electrode before cycle when batteries discharged to 1.0 V. Experimental results of P-C-T show that the electrochemical capacities of alloy are 129.4 mAh/g after 303 cycles and 279.7 mAh/g before cycle, that is the hydrogen content of alloy decreases greatly. Through analyzing scanning electron macrographs, mastersizer and XRD spectra of active materials of positive and negative electrode at 303 cycles and before cycle, it proved that the main reason of lapse of D size Ni-MH batteries after long cycles is that the alloys of negative electrode are corrupted, oxidized and pulverized.

关 键 词：MH-NI电池 失效机理 贮氢合金 高倍率 循环寿命 

分 类 号：TM912.2[电气工程—电力电子与电力传动]