Preliminary design of 1 kW bipolar Ni-MH battery for LEO-satellite application

Electro Energy, Inc. (EEI) is developing a bipolar nickel-metal hydride rechargeable battery based upon the use of stackable wafer cells. The key to viable bipolar operation has been this unique modular (unitized) approach. The patented unit wafer-cell construct exploits the chemical and thermal properties of a proprietary electrically conductive plastic film. Characteristic of bipolar batteries, current flows across the cell interfaces-perpendicular to the electrode plane. EEI has recently contracted with NASA Lewis Research Center (LeRC) to develop an optimized design 1 kW flightweight battery, for low-Earth-orbit (LEO) satellite applications, over a 4-year period with a deliverable flightweight design package. The contract includes an option for EEI to deliver up to three flight quality batteries in an 18-month follow-on program. NASA LeRC has promulgated that the program steps include the design, fabrication, and evaluation of four evolutionary stages of the final battery design which have been designated preliminary, improved, optimized and flightweight design. Initial results from the preliminary stage are presented including a 1 kW battery design, thermal design, parameter study, and component development in subscale bipolar batteries.