The Cycle Life Performance of MH-Ni Batteries for High Power Applications

摘要

Because of few environment pollution of Ni/MH battery compared with Ni/Cd battery, the demand of the high-rate cylinder nickel metal hydride battery is growing in high power applications, and the annual consume amount is above 5 hundred millions. But now some performances of Ni/MH battery can't meet the requirement for usage of electrical tools, especially the poor charge&discharge cycle life. So the development of high-rate nickel metal hydride battery with high performance is very important both in the scientific research and the market applications. The mainly contents in this paper are the study of effects on the charge&discharge cycle life and degradation of sub-C type Ni-MH power batteries. The change of impedance, temperature, and weight loss are investigated in the process of cycle life test. The cause for increase of battery internal resistance is also analysis by SEM method. We think increase of the internal resistance of battery is the main problem to the poor cycle life at high rate, besides the performance deteriorates of the electrode materials. Swell occurred on positive and pulverization on negative electrode at high rate current, make the pore space increased and the electrolyte depleted. The restrains of swelling and the increase of capacity of negative electrode can improve the performance of cycle life.