Method to reduce the internal pressure of a sealed rechargeable hydride

Abstract

This invention provides a method to reduce the internal pressure of a hydride battery, particularly a sealed type. The battery, according to this invention, is composed of a container, a positive electrode, a negative electrode suitable for various temperatures comprising at least two hydrogen storage electrode materials and/or their hydrides, a separator positioned between the positive and negative electrodes, and an electrolyte in the container and in contact with the positive and negative electrodes and the separator. The negative electrode is a hydrogen storage hydride electrode which is composed of at least two hydrogen storage electrode alloys having compositions represented by A.sub.a B.sub.b C.sub.c. . . and A'.sub.a,B'.sub.b C'.sub.c, . . . respectively; where the set of elements: A, B, C, . . . and the set of elements: A', B', C', . . . both consist of 6 to 80 at. % of nickel, preferably 24-55 at. % nickel; and at least four other elements chosen from the group consisting of Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, Y, Zr, Nb, Pd, Ag, Mo, Ca, Si, C, Cu, Ta, Ca, rare earth metals, B, Hf, Sc, Zn, Sb, W, Sn, N, O, Ge, Ga, the alkali metals, P, and S; the sets of atomic mole ratio a, b, c, . . . and a', b', c', . . . are defined by the heats of hydride formation H.sub.h and H'.sub.h respectively; where H.sub.h and H'.sub.h are in a range of between -2.50 and -10.50 Kcal/mole H, preferably between -3.50 and -8.50 Keal/mole H; and at least one of the compositions consists of more than 40 at. % of nickel, preferably more than 47 at. % of nickel; and at least one of the heats of hydride formation of the alloys is in the range between -7.50 and -2.50 Kcal/mole H, preferably between -7.08 and -2.80 Kcal/mole H.