BATTERY CAN, BATTERY USING THE SAME, AND METHOD FOR MANUFACTURING THE SAME
A battery can is manufactured by drawing and ironing a nickel plated steel plate. The nickel plated steel plate includes a steel plate and a nickel plating layer made of nickel grains layered. Nickel grains present in a surface portion of the nickel plating layer are greater than nickel grains present in the vicinity of the interface with the steel plate.
1 . A bottomed cylindrical battery can formed of a nickel plated steel plate, comprising:
a steel plate; and
a nickel plating layer made of nickel grains, the nickel grains having sectional areas measured in sections thereof in parallel to the thickness direction of the nickel plating layer,
wherein in a portion of the bottom face of the battery can which is substantially perpendicular to the side face thereof, A is in a range between 0.2 μm 2 and 0.5 μm 2 , both inclusive, and 0.1<B/A<0.5 is satisfied where A is an average of sectional areas of nickel grains present in a surface portion of the nickel plating layer which ranges from the surface of the nickel plating layer to a part of the nickel plating layer which is 30% deep in a thickness direction of the nickel plating layer from the surface thereof while B is an average of sectional areas of nickel grains present in an interface portion of the nickel plating layer which ranges from an interface with the steel plate to a part of the nickel plating layer which is 30% shallow in the thickness direction of the nickel plating layer from the interface therewith.
2 . The battery can of claim 1 ,
wherein the nickel plating layer has a thickness in a range between 0.5 μm and 5 μm, both inclusive.
3 . A battery using the battery can of claim 1 .
4 . The battery of claim 3 ,
wherein the battery is an AA alkaline dry battery which generates gas of which total amount is 0.3 ml or less in four-week storage under an atmosphere of 80° C.
5 . A method for manufacturing a bottomed cylindrical battery can from a nickel plated steel plate, comprising the steps of:
preparing a nickel steel plate including a steel plate and a nickel plating layer made of nickel grains, the nickel grains having sectional areas measured in sections thereof in parallel to the thickness direction of the nickel plating layer,
forming a cup-shaped intermediate from the nickel plated steel plate by deep drawing; and
forming a battery can by drawing and ironing the cap-shaped intermediate,
wherein in a the nickel plating layer of the nickel plated steel plate, A is in a range between 0.2 μm 2 and 0.5 μm 2 , both inclusive, and 0.1<B/A<0.5 is satisfied where A is an average of sectional areas of nickel grains present in a surface portion of the nickel plating layer which ranges from the surface of the nickel plating layer to a part of the nickel plating layer which is 30% deep in a thickness direction of the nickel plating layer from the surface thereof while B is an average of sectional areas of nickel grains present in an interface portion of the nickel plating layer which ranges from an interface with the steel plate to a part of the nickel plating layer which is 30% shallow in the thickness direction of the nickel plating layer from the interface therewith, and
no annealing is performed on the nickel plated steel plate.