Sealed rechargeable battery

Abstract

A sealed rechargeable battery has an electrode group formed by winding a positive electrode and a negative electrode through a separator. A plurality of radial slits are provided in a welding section that is formed by an exposed section of a collector of at least one of the positive electrode and the negative electrode exposed at both ends of the electrode group. In the welding section, the exposed section is folded from the winding axis side toward the outer periphery to form a flat welding face.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a cylindrical lithium-ion rechargeable battery in accordance with an exemplary embodiment of the present invention.

FIG. 2A is a perspective view showing a state before processing of an electrode group of the cylindrical lithium-ion rechargeable battery shown in FIG. 1.

FIG. 2B is a partial perspective view showing a state after the processing of the electrode group shown in FIG. 2A.

FIG. 3 is a sectional view of another cylindrical lithium-ion rechargeable battery in accordance with the exemplary embodiment.

FIG. 4 is a developed view of a positive electrode and a negative electrode of the latter cylindrical lithium-ion rechargeable battery in accordance with the exemplary embodiment.

FIG. 5 is a developed view of a positive electrode and a negative electrode of yet another cylindrical lithium-ion rechargeable battery in accordance with the exemplary embodiment.

FIG. 6 is a partial perspective view of an electrode group formed of the positive and negative electrodes shown in FIG. 4 or those shown in FIG. 5.

FIG. 7A is a sectional view of a conventional cylindrical lithium-ion rechargeable battery of tabless type.

FIG. 7B is a developed view of electrodes of the cylindrical lithium-ion rechargeable battery shown in FIG. 7A.

Claims

1. A sealed rechargeable battery comprising: an electrode group including: a first electrode having a first collector provided with a first exposed section at one end thereof in the width direction, and a first active material layer disposed on the first collector;a second electrode having a second collector provided with a second exposed section at one end thereof in the width direction, and a second active material layer disposed on the second collector; anda separator interposed between the first electrode and the second electrode,the electrode group being formed by winding so that the first exposed section and the second exposed section are exposed on opposite sides;an electrolyte, the electrode group being impregnated with the electrolyte;a first collecting plate welded to a first welding section formed of the first exposed section of the wound first electrode;a second collecting plate welded to a second welding section formed of the second exposed section of the wound second electrode;a case configured to store the electrode group and the electrolyte, the first collecting plate being coupled to an inner bottom face of the case; anda sealing plate having a terminal coupled to the second collecting plate, the sealing plate being applied to an opening of the case,wherein a plurality of radial slits are provided in at least one of the first welding section and second welding section,and in at least one of the first welding section and second welding section having the slits, at least one of the first exposed section and second exposed section is folded from a winding axis side toward an outer periphery and forms a flat welding face.

2. The sealed rechargeable battery according to claim 1, further comprising an insulating section disposed between an outer periphery of the second welding section and the case.

3. The sealed rechargeable battery according to claim 1, wherein an outer periphery of the second welding section is substantially identical with an outline of the electrode group.

4. The sealed rechargeable battery according to claim 3, wherein width of the second exposed section gradually decreases from the winding axis side toward the outer periphery side.

5. The sealed rechargeable battery according to claim 3, wherein the second exposed section is disposed only on an inner periphery side of the winding.