Photovoltaic testing of 2 kWh common pressure vessel nickel hydrogen batteries

A common pressure vessel (CPV) nickel-hydrogen battery for terrestrial applications has been developed. A 7 kWh boilerplate battery and four 2 kWh batteries are being tested for a variety of photovoltaic applications. During initial testing, the 7 kWh battery delivered 7.85 kWh. In recent testing, the battery delivered over 9.5 kWh. From the onset of testing, one cell in one 2 kWh battery showed evidence of shorting, resulting in a reduced voltage and capacity. Despite this problem, the series-connected battery pair has consistently delivered more than the nominal 4 kWh energy capacity during characterization cycling