The Measurement of Nickel Hydrogen Cell Performance Characteristics with Pressure as a State of Charge Indication

Hydrogen gas pressure has been utilized to determine state of charge, efficiency on charge, establish voltage/current relationships and to derive an equivalent cell level DC resistance. In response to a fixed measurement cycle, the studied cell design is able to store more charge at lower temperatures. This is accomplished by more efficient charging to a higher cell voltage. However, as higher states of charge (pressure) are attained, the discharge profile depresses. This corresponds to an increased cell DC resistance. Furthermore, this cell level DC resistance increases with the depth of discharge and the rate of this increase is greater at lower temperatures.