Patent ID: 7879497

Claim:
A battery comprising a positive electrode plate including: 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 nickel hydroxide particle group including a number of nickel hydroxide particles filled in the void part of the positive electrode substrate; wherein the nickel hydroxide particle group includes, at a ratio of 15 wt % or less, nickel hydroxide particles each having a particle diameter of 5 μm or less, and the positive electrode substrate is configured such that, when the positive electrode substrate is divided into five regions in a thickness direction, a region closest to a positive-electrode-substrate front surface is a front-surface-side nickel portion, a region closest to a positive-electrode-substrate back surface is a back-surface-side nickel portion, and a middle region is a middle nickel portion, a front-surface-side nickel layer forming the nickel skeleton of the front-surface-side nickel portion and a back-surface-side nickel layer forming the nickel skeleton of the back-surface-side nickel portion are larger in thickness than a middle nickel layer forming the nickel skeleton of the middle nickel portion, and an average thickness B of a thicker one of either the front-surface-side nickel layer or the back-surface-side nickel layer, and an average thickness C of the middle nickel layer, satisfy a relation of 0.6≦C/B≦0.9.