Patent ID: 7736795

Claim:
A battery comprising an electrode plate assembly having: a plurality of positive electrode plates each of which includes: a positive electrode substrate made of nickel and including a nickel skeleton of a three-dimensional network structure having a void part formed of a number of pores three-dimensionally connected, the positive electrode substrate having a front surface and a back surface, and a positive mix material filled in the void part of the positive electrode substrate; a plurality of negative electrode plates each of which includes: a negative electrode substrate made of metal having a front surface and a back surface, a front-surface-side negative mix material layer provided on the negative-electrode-substrate front surface and a back-surface-side negative mix material; and a plurality of separators; the positive electrode plates and the negative electrode plates being alternately laminated with the separators interposed one by one between them, wherein each the positive electrode substrate is configured to satisfy a relation of A<B, where “A” is an average thickness of a front-surface-side nickel layer forming the nickel skeleton constituting a front-surface-side nickel portion and “B” is an average thickness of a back-surface-side nickel layer forming the nickel skeleton constituting a back-surface-side nickel portion, assuming that the positive electrode substrate is divided into five regions in a thickness direction, a region closest to the positive-electrode-substrate front surface is the front-surface-side nickel portion and a region closest to the positive-electrode-substrate back surface is the back-surface-side nickel portion, and each of the negative electrode plates is configured to satisfy a relation of D<E, where “D” is a thickness of the front-surface-side negative mix material layer and “E” is a thickness of the back-surface-side negative mix material layer, and the positive electrode plates and the negative electrode plates are laminated so that all the positive-electrode-substrate front surfaces and the negative-electrode-substrate front surfaces face to the same side in the lamination direction.