Patent ID: 7923145
Filing Date: 2011-04-12
Classification: C23C,C25D,H01M,Y02E,Y10T

Abstract:
1. A battery case comprises a surface treated steel sheet, said surface treated steel comprising: a steel sheet having two surfaces, one of said two surfaces to be used as the inner surface of the battery case and the other of said two surfaces to be used as the outer surface of the battery case; a diffusion layer of a nickel-cobalt-phosphorus alloy having a thickness in the range of 0.1 to 2 μm and formed as an uppermost layer at said one of said two surfaces to be used as the inner surface of the battery case; an iron-nickel diffusion layer between said diffusion layer of a nickel-cobalt-phosphorus alloy and said steel sheet; a nickel layer having a thickness in the range of 0.2 to 3 μm and formed as an upper layer at said one of said two surfaces to be used as the outer surface of the battery case; and an iron-nickel diffusion layer between said nickel layer and said steel sheet.