Nickel-hydrogen batteries - An overview

This article on nickel-hydrogen batteries is an overview of the various nickel-hydrogen battery design options, technical accomplishments, validation test results, and trends, There is more than one nickel-hydrogen battery design, each having its advantage for specific applications, The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar, and low-pressure metal hydride, State-of-the-art nickel-hydrogen batteries are replacing nickel-cadmium batteries in almost all geosynchronous Earth orbit applications requiring power above 1 kW, However, for the more severe low-Earth orbit (LEG) applications (>30,000 cycles), the current cycle life of 4000-10,000 cycles at 60-80% DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel-hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low-cost satellites. Hence, the challenge is to reduce battery mass, volume, and cost, A key is to develop a lightweight nickel electrode and alternate battery designs, A CPV nickel-hydrogen battery is emerging as a viable alternative to the IPV design, It has the advantage of reduced mass, volume, and manufacturing costs, A 10-A-h CPV battery has successfully provided power on the relatively short-lived Clementine spacecraft, A bipolar nickel-hydrogen battery design has been demonstrated (15,000 LEO cycles, 40% DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high-pulse power capability, A low-pressure aerospace nickel-metal-hydride battery cell has been developed and is on the market, It is a prismatic design that has the advantage of a significant reduction in volume and a reduction in manufacturing cost.