Satellite battery thermal/capacity design

Abstract

A method is disclosed of operating a nickel-hydrogen battery when the battery is less than fully charged. Specifically, battery recharge is completed at a temperature T.sub.1, in the range of approximately -10.degree. C. to -30.degree. C. which is lower than a temperature T.sub.2 in the range of approximately -10.degree. C. to +5.degree. C., at which discharge begins. The temperature T.sub.1 is chosen to maximize the extent of the reaction represented by the equation: Ni(OH).sub.2 +OH.sup.- =NiOOH+H.sub.2 O+e.sup.-. versus the reaction represented by the equation: H.sub.2 O+2e.sup.- =OH.sup.- +1/2O.sub.2 Subsequently, it is desirable to heat the battery to the temperature T.sub.2 in readiness for discharge. A preferred recharge temperature is less than approximately -10.degree. C. The battery includes a positive electrode which may include electrochemically active Ni(OH).sub.2 possibly mixed with Co(OH).sub.2 and electrically conductive material having a resistivity less than approximately 0.1 ohm-cm, a negative electrode which is of a material which catalyzes the oxidation and reduction of H.sub.2, and an electrolyte which is a solution of KOH.

Dependencies are inferred from the claim text.