Battery armoring stainless steel foil, and method of producing same

Patent metadata

Field	Value
Publication number	US-10087498-B2
Application number	US-201615577730-A
Country	US
Kind code	B2
Filing date	May 20, 2016
Priority date	May 29, 2015
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

Provided is a battery armoring stainless steel foil which has excellent adhesiveness to resin after being thermally shocked and after being immersed in an electrolyte solution. A battery armoring stainless steel foil ( 1 ) includes an oxide film ( 1 a ), having a thickness of not less than 2 nm, which contains (i) Fe in an amount of not less than 40 mol percent, (ii) Cr in a lesser amount than Fe, and (iii) Si in an amount of not more than 40 mol percent, the battery armoring stainless steel foil ( 1 ) having an arithmetic mean roughness Ra of less than 0.1 μm but not less than 0.02 μm in a direction orthogonal to a direction in which the battery armoring stainless steel foil ( 1 ) has been rolled.

First claim

The invention claimed is:

1. A battery armoring stainless steel foil comprising:
an oxide film, having a thickness of not less than 2 nm, which contains (i) Fe in an amount of not less than 40 mol percent (ii) Cr in a lesser amount than Fe, and (iii) Si in an amount of not more than 40 mol percent; and
the battery armoring stainless steel foil having an arithmetic mean roughness Ra of less than 0.1 μm but not less than 0.02 μm in a direction orthogonal to a direction in which the battery armoring stainless steel foil has been rolled.

2. The battery armoring stainless steel foil according to claim 1 , wherein
the thickness of the oxide film is not more than 5 nm.

3. A method of producing a battery armoring stainless steel foil recited in claim 1 , the method comprising the steps of:
obtaining a rolled stainless steel foil which has an arithmetic mean roughness Ra of less than 0.1 μm but not less than 0.02 μm in a direction orthogonal to a direction in which the rolled stainless steel foil has been rolled; and
forming an oxide film by annealing the rolled stainless steel foil at a temperature in a range of 900° C. to 1180° C. in a reducing atmosphere in which (i) a dew point falls in the range of −40° C. to −60° C. and (ii) a hydrogen partial pressure is not less than 75%.

4. A method of producing a battery armoring stainless steel foil recited in claim 2 , the method comprising the steps of:
obtaining a rolled stainless steel foil which has an arithmetic mean roughness Ra of less than 0.1 μm but not less than 0.02 μm in a direction orthogonal to a direction in which the rolled stainless steel foil has been rolled; and
forming an oxide film by annealing the rolled stainless steel foil at a temperature in a range of 900° C. to 1180° C. in a reducing atmosphere in which (i) a dew point falls in the range of −40° C. to −60° C. and (ii) a hydrogen partial pressure is not less than 75%.

Assignees

• Nisshin Steel Co Ltd

Inventors

• Ueda Daichi
• Matsuo Shoichi
• Fujii Takahiro
• Hirakawa Naoki
• Sugita Shuichi
• Oda Yukio

Classifications

• C21D1/76 Primary

  Adjusting the composition of the atmosphere · CPC title

• C21D8/0273

  Final recrystallisation annealing · CPC title

• C22C38/18

  containing chromium · CPC title

• C21D9/46

  for sheet metals · CPC title

• B32B15/18

  comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} · CPC title