Effect of cobalt powder on the inner pressure of Ni/MH batteries

Abstract The effect of three kinds of cobalt powder of different mean diameter added to the negative electrode on the inner pressure of Ni/MH batteries during charging was examined. Experiments showed that batteries with finer Co powder displayed a much lower inner gas pressure on charging than batteries with coarser Co powder. The inner gas pressure of the cells increased with increasing charge/discharge cycle, and the cell with the finest Co powder showed the slowest inner pressure increase and had the longest cycle life.