Steel foil for power storage device container, power storage device container, power storage device, and manufacturing method of steel foil for power storage device container
View Patent ↗A steel foil for a power storage device container includes a rolled steel foil which has a thickness of 200 μm or less, a diffusion alloy layer which is formed on a surface layer of the rolled steel foil and contains Ni and Fe, and a chromium-based surface treatment layer which is formed on the diffusion alloy layer. The <111> polar density in a reverse pole figure of the diffusion alloy layer in a rolling direction is 2.0 to 6.0, and the aspect ratio of crystal in a surface of the diffusion alloy layer is 1.0 to 5.0.
1. A steel foil for a power storage device container comprising:
a rolled steel foil which has a thickness of 200 μm or less;
a diffusion alloy layer which is formed on a surface layer of the rolled steel foil and contains Ni and Fe; and
a chromium-based surface treatment layer which is formed on the diffusion alloy layer,
wherein <111> polar density in a reverse pole figure of the diffusion alloy layer in a rolling direction is 2.0 to 6.0, and
wherein an aspect ratio of a crystal in a surface of the diffusion alloy layer is 1.0 to 5.0.
2. The steel foil for a power storage device container according to claim 1 , wherein
I FeNi3 /I Ni which is a ratio between a intensity I Ni of a diffraction peak of Ni and a intensity I FeNi3 of a diffraction peak of FeNi 3 which are obtained by measuring X-ray diffraction on the diffusion alloy layer is equal to or higher than 5.0 or the diffraction peak of Ni is not detected.
3. The steel foil for a power storage device container according to claim 1 , further comprising:
a polyolefin-based resin layer which is formed on a surface of the chromium-based surface treatment layer.
4. A power storage device container which includes the steel foil for a power storage device container according to claim 3 .
5. A power storage device comprising:
the power storage device container according to claim 4 .
6. A manufacturing method of a steel foil for a power storage device container, the method comprising:
a nickel-plating process of performing a nickel plating on a steel sheet so as to form a Ni-plated layer on the steel sheet, and obtaining a Ni-plated steel sheet;
an annealing process of annealing the Ni-plated steel sheet so that Fe in the steel sheet and Ni in the Ni-plated layer are mutually diffused;
a cold-rolling process of performing a cold rolling on the Ni-plated steel sheet at cumulative rolling reduction of 70% or higher, and obtaining a steel foil;
a recrystallization annealing process of annealing the steel foil at 750° C. to 1100° C. for 4 to 120 seconds under an annealing condition in which Tc and Ta satisfy the following expression (1) in a case of 750≤Ta≤800 and satisfy the following expression (2) in a case of Ta>800, wherein an annealing time is defined as Tc in an unit second, and an annealing temperature is defined as Ta in an unit of ° C.; and
a chromium-based surface treatment process of performing a chromium-based surface treatment on the steel foil;
Tc≥ 13−0.1×( Ta− 750) (1)
Tc≥ 8−(4/300)×( Ta− 800) (2).
7. The manufacturing method of a steel foil for a power storage device container, according to claim 6 , wherein
in the recrystallization annealing process, the Tc and the Ta satisfy the following expression (3) in a case of 750≤Ta≤800, and satisfy the following expression (4) in a case of Ta>800,
Tc≥ 16−0.1×( Ta− 750) (3)
Tc≥ 11−0.02×( Ta− 800) (4).
8. The manufacturing method of a steel foil for a power storage device container, according to claim 6 , further comprising:
a polyolefin resin layer forming process of forming a polyolefin resin layer on a surface of the steel foil after the chromium-based surface treatment process by a thermal laminate method.
9. The steel foil for a power storage device container according to claim 2 , further comprising:
a polyolefin-based resin layer which is formed on a surface of the chromium-based surface treatment layer.
10. A power storage device container which includes the steel foil for a power storage device container according to claim 9 .
11. A power storage device comprising:
the power storage device container according to claim 10 .
12. The manufacturing method of a steel foil for a power storage device container, according to claim 7 , further comprising:
a polyolefin resin layer forming process of forming a polyolefin resin layer on a surface of the steel foil after the chromium-based surface treatment process by a thermal laminate method.