Post Storage Conditioning of Nickel-Hydrogen Battery Cells

Extended room temperature storage of nickel-hydrogen battery cells has resulted in a capacity loss when the cells are initially cycled following the storage period. Because it may be necessary to “store” nickel-hydrogen batteries for long periods at room temperature (i.e., shipment, installation, etc.), tests were performed to establish the effects on capacity recovery of several post-storage conditioning methods. The tests included two groups of cells; a 60-day storage group and 120-day storage group. Each group comprised three 2-cell packs. The capacity of each cell was measured under the same controlled conditions both prior to storage and after post-storage conditioning. Each 2-cell pack in a group was conditioned differently over a 13-day period following storage. The results attained with the 60-day storage group were essentially confirmed with the 120-day storage group. In addition, Group 1 was subjected to a second 60-day storage period after which the effects of variations of the conditioning methods were evaluated. The paper describes in detail the cell design, the test procedures, and the test results.