Patent ID: 11936046
Assignee: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC C  H  Y | IPC C  H

Claim 0:
1. An electricity storage device, comprising:
a stack of electrodes each including a steel sheet,
a plating layer provided on a surface of the steel sheet, and
a resin spacer disposed along a peripheral portion of each of the electrodes and in contact with the plating layer, wherein
the plating layer includes
a base nickel-plating layer provided on the surface of the steel sheet, and
a surface nickel-plating layer provided on the base nickel-plating layer and having a plurality of protrusions protruding in a direction intersecting with a direction in which the surface of the steel sheet extends;

at least some of the protrusions are each provided with an enlarged portion positioned nearer to a tip end of each of the protrusions rather than a base end of each of the protrusions;
the base nickel-plating layer entirely covers the surface of the steel sheet and is formed as a continuous film;
the base nickel-plating layer having a plurality of convex projections protruding in a direction of the surface nickel-plating layer, such that a surface profile of the base nickel-plating layer does not follow the surface of the steel sheet and is rougher than a surface profile of the surface of the steel sheet;
the enlarged portion is formed by building up a plurality of metal deposits;
the enlarged portion has a length size that is greater than a length size of the base end in the direction in which the surface of the sheet steel extends;
the electrodes are a plurality of bipolar electrodes each having a current collector formed from a nickel-plated steel sheet, a positive electrode layer provided on one side of the current collector, and a negative electrode layer provided on an other side of the current collector;
the stack is formed of the plurality of bipolar electrodes being stacked via separators; and
the number of protrusions per unit area of the surface nickel-plating layer in a plan view is equal to or greater than 2,500/mm2 and equal to or less than 7,000/mm2, wherein
the electricity storage device further comprises a casing holding a peripheral portion of the current collector via the resin spacer.