Cell safety valve and cell having same

• US 20030131880A1
• Filed: 12/19/2002
• Published: 07/17/2003
• Est. Priority Date: 12/20/2001
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Fujii, Shigeki, Tobita, Yoshihiro, Marubayashi, Hironori, Morishita, Takuma
• Granted Patent: US 7,140,380 B2
• Time in Patent Office: Days
• US Class Current: 137/68.27
• CPC Class Codes: H01M 50/3425 in the form of rupturable membranes or weakened parts, e.g. pierced with the aid of a sharp member
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 137/1729 Dome shape
• CPC Class Codes: Y10T 137/1744 Specific weakening point

Abstract

A cell according to the present invention comprises a positive electrode, a negative electrode, an electrolyte solution, and an outer casing, wherein the outer casing comprises a valve plate 30 having a thickness, an annular-shaped break groove 4 formed on the valve plate, and one or more of break aiding grooves 1 in the inner area of the break groove, and wherein the break aiding groove comprises such configurations that remaining thickness of the valve plate at the break aiding groove is thicker than remaining thickness of the valve plate at the break groove, and at least one end of the break aiding groove is connected with the break groove. In a cell provided with a valve plate which is a safety valve 9 comprising the break groove and the break aiding groove, the safety valve operates smoothly and releases a gas inside the cell quickly, and resistance to dropping impact is improved.

Claims

1. A cell safety valve comprising a valve plate having a thickness, an annular-shaped break groove formed on the valve plate, and one or more of break aiding grooves in an inner area of the break groove,

wherein the break aiding groove comprises such configurations that remaining thickness of the valve plate at the break aiding groove is thicker than remaining thickness of the valve plate at the break groove, and at least one end of the break aiding groove is connected with the break groove.

2. The cell safety valve according to claim 1, wherein both ends of the break aiding groove are connected with the break groove.

3. The cell safety valve according to claim 1, wherein the break aiding groove passes through a center of the valve plate.

4. The cell safety valve according to claim 2, wherein among two or more areas of the valve plate divided by the break groove and the break aiding groove, at least one of the areas is dome-shaped.

5. The cell safety valve according to claim 1, wherein the break groove has such an annular shape as a circle or an ellipse-like shape.

6. The cell safety valve according to claim 1, wherein difference in remaining thickness of the valve plate between the break groove and the break aiding groove is 5 μ

m or more.

7. The cell safety valve according to claim 1, wherein a bottom portion of the break aiding groove of the valve plate is wider than a bottom portion of the break groove of the valve plate.

8. The cell safety valve according to claim 1, wherein a cross section of the break groove of the valve plate is V-shaped, and a cross section of the break aiding groove of the valve plate is U-shaped.

9. A cell comprising a positive electrode, a negative electrode, an electrolyte, and an outer casing,

wherein the outer casing comprises a valve plate having a thickness, an annular-shaped break groove formed on the valve plate, and one or more of break aiding grooves in an inner area of the break groove;

and

wherein the break aiding groove comprises such configurations that remaining thickness of the valve plate at the break aiding groove is thicker than remaining thickness of the valve plate at the break groove, and at least one end of the break aiding groove is connected with the break groove.