Sealed battery

Abstract

A sealed battery according to the present invention includes a sealing body 18A having a terminal cap 19′ made of an iron-based material and a safety valve 25 made of an aluminum-based material. In the sealing body 18A, at least one of the flange of the terminal cap 19′ and the flange of the safety valve 25 has a portion defining a space 30. The flanges of the terminal cap and of the safety valve are welded at a position corresponding to the space with high-energy rays. It is thus possible to provide the sealed battery including the sealing body having a current interrupt function in which resistance between the terminal cap and the safety valve is kept low, thereby being suitable for large-current applications.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged sectional view of a sealing body used in a first embodiment according to the present invention.

FIG. 2 is an enlarged sectional view of a sealing body used in a second embodiment according to the invention.

FIG. 3 is an enlarged sectional view of a sealing body used in a comparative example.

FIG. 4 is a perspective view showing a longitudinal section of a related-art cylindrical nonaqueous electrolyte secondary battery.

FIG. 5 is an enlarged partial cutaway view of a sealing body shown in FIG. 4.

FIG. 6 is an enlarged sectional view of a sealing body used in a related-art secondary battery for large current discharge.

FIG. 7 is an enlarged sectional view of a sealing body having a current interrupt function without requiring a related-art PTC thermistor element.

Claims

1. A sealed battery comprising: a sealing part, said sealing part including: an inverted-dish-shaped terminal cap made of an iron-based material and provided to at least one of a negative electrode and a positive electrode of said battery; anda dish-shaped safety valve made of an aluminum-based material for interrupting electrical connection between inside and outside of said battery;at least one of a flange face of said terminal cap and a flange face of said safety valve facing each other having a portion defining a space, andsaid flange of said terminal cap and said flange of said safety valve being welded at a position corresponding to said space with a high-energy ray.

2. The sealed battery according to claim 1, wherein said space is an annular groove.

3. The sealed battery according to claim 1, wherein said space is at least 0.05 mm deep and at most half as deep as any side having said space.

4. The sealed battery according to claim 1, wherein said high-energy ray is a laser beam or an electron beam.

5. A sealed battery comprising: a sealing part, said sealing part including: an inverted-dish-shaped terminal cap made of an iron-based material and provided to at least one of a negative electrode and a positive electrode of said battery;a dish-shaped safety valve made of an aluminum-based material for interrupting electrical connection between inside and outside of said battery; anda ring-like interposed material interposed between said terminal cap and said safety valve, made of a material identical to a material for said safety valve, and being as thick as or thinner than said safety valve;said interposed material and said safety valve being welded with a high-energy ray,at least one of a flange face of said terminal cap and a face of said interposed material facing each other having a portion defining a space, andsaid flange of said terminal cap and said interposed material being welded at a position corresponding to said space with a high-energy ray.

6. The sealed battery according to claim 5, wherein said interposed material is at most 70% as thick as said terminal cap.

7. The sealed battery according to claim 5, wherein said space is an annular groove.

8. The sealed battery according to claim 5, wherein said space is at least 0.05 mm deep and at most half as deep as any side having said space.

9. The sealed battery according to claim 5, wherein said high-energy ray is a laser beam or an electron beam.