Manufacturing method for battery case lid including explosion-proof valve

Patent metadata

Field	Value
Publication number	US-10340490-B2
Application number	US-201715481048-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Oct 13, 2010
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A battery case lid is formed by working a metal plate, and includes a substrate section and an explosion-proof valve formed in the substrate section. The explosion-proof valve has a reduced thickness section thinner than the substrate section, and the reduced thickness section is formed by extending the metal plate by applying pressure while the metal plate is kept unrestrained.

First claim

The invention claimed is:

1. A manufacturing method for a battery case lid including an explosion-proof valve, the manufacturing method comprising:
pushing an extending punch from a first side of a metal plate disposed over an extending die having a recess, to form a reduced thickness section constituting the explosion-proof valve, wherein
the recess has an inner diameter greater than an outer diameter of the extending punch, and
an external corner portion of the recess and a top section on a side face of the extending punch have a peripheral portion arc-shaped in cross section, the top section being formed by an end of the extending punch facing the recess, wherein
a clearance between a side face of the recess of the extending die and an outer periphery at the top section on the side face of the extending punch is set to be smaller than a thickness of the metal plate, and wherein
the extending punch is pushed while the metal plate is kept unrestrained, and a portion of the metal plate that first starts moving is sandwiched between an inner periphery at the external corner portion of the recess and the outer periphery at the top section on the side face of the extending punch, and
the metal plate is pressed to be extended between a bottom face of the recess and a pressing face of the extending punch, to form the reduced thickness section and a cylindrical wall portion.

2. The manufacturing method for the battery case lid of claim 1 , further comprising forming a groove in the reduced thickness section.

3. The manufacturing method for the battery case lid of claim 1 , wherein the cylindrical wall portion is formed around the reduced thickness section, the cylindrical wall portion having a height greater than a depth of the recess of the extending die.

4. The manufacturing method for the battery case lid of claim 1 , further comprising pressing the reduced thickness section by a bending punch smaller in the outer diameter than the reduced thickness section from a second side of the metal plate, to bend the cylindrical wall portion formed around the reduced thickness section.

5. The manufacturing method for the battery case lid of claim 4 , further comprising pushing a bent portion formed by bending the cylindrical wall portion by a folding punch from the second side of the metal plate, to fold the bent portion.

6. The manufacturing method for the battery case lid of claim 1 , wherein the pressing face of the extending punch has a spherical face which is convex in a pressing direction of the extending punch.

7. The manufacturing method for the battery case lid of claim 1 , further comprising correcting the reduced thickness section to be flat.

8. The manufacturing method for the battery case lid of claim 4 , further comprising forming a groove in the reduced thickness section, wherein the reduced thickness section is pressed by a groove forming punch from the second side of the metal plate to form the reduced thickness section with the groove.

9. The manufacturing method for the battery case lid of claim 5 , further comprising forming a groove in the reduced thickness section, wherein the reduced thickness section is pressed by a groove forming punch from the second side of the metal plate to form the reduced thickness section with the groove.

10. The manufacturing method for the battery case lid of claim 6 , wherein the bottom face of the recess has a spherical surface which is downwardly convex, and a curvature radius of the spherical face of the pressing face is equal to or smaller than a curvature radius of the spherical face of the bottom face of the recess.

Assignees

• Soode Nagano Co Ltd
• Nippon Light Metal Co

Inventors

• Sode Takayuki
• Sugiyama Yukinori
• Nomura Shinichi
• Kobayashi Masato

Classifications

• B21C23/186 Primary

  by backward extrusion · CPC title

• B21D11/08

  Bending by altering the thickness of part of the cross-section of the work (B21D11/06 takes precedence) · CPC title

• H01M2/1241 Primary

  Electricity · mapped topic

• B21D51/383

  scoring lines, tear strips or pulling tabs · CPC title

• B21D51/44

  Making closures, e.g. caps (folded of thin metal foils in the way of making paper caps B31D5/00; making closures in conjunction with applying same B67B) · CPC title