Gerald Halpert

Past developments and the future of nickel electrode cell technology

The nickel hydroxide electrode has evolved over nearly 100 years from the pocket electrode structure through to the present design of a light weight, porous, plaque structure. Before discussing the historical aspects, it would be helpful to point out that there are basically two parts to the electrode: the active material and the current (electron) collector. Together they provide the essential properties for storing and converting the chemical energy into electrical energy and vice versa. The electrical energy is stored in the nickel hydroxide active material during charge, in which the electrode is oxidized. The chemical energy is converted back to electrical energy during discharge. The active material is itself initially non-conductive. Therefore it must be housed in a high conductivity metallic structure which serves as the current collector. This is, in turn, connected to another high conductivity metallic structure called the terminal.

Computer simulation of thermal modeling of primary lithium cells

Abstract The objective of this program was to gain a better understanding of the safety problems of primary Liue5f8SOCl 2 and Liue5f8SO 2 cells by carrying out detailed thermal modeling work. In particular, the transient heat generation rates during moderate and extremely high discharge rate tests of Liue5f8SOCl 2 cells were predicted and compared with those from the electrochemical heating. The difference between the two may be attributed to lithium corrosion and other chemical reactions. The present program was also evaluated in charging tests of Liue5f8SO 2 cells. In addition, the present methodology should be applicable, with minor modifications, to analyses of other primary cylindrical cells as well as rechargeable batteries.