JPH10199495A - Sealed structure of sealed battery and gasket to be used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed structure by which seal performance by a gasket itself can be improved further without applying a sealant further to a gasket surface, and the gasket therefor in a sealed battery. SOLUTION: A sealing member 2 is joined by interposing a gasket 3 in an opening of a battery can 1, and the battery inside is sealed. The gasket 3 has an annular base body part 4 interposable over the whole opening periphery between contact planes of the sealing member 2 and a battery can wall 1A around an opening, and a mountain range-shaped projecting part 5 ranging by drawing a closed ring along the whole periphery around the opening, is arranged on one or mores surfaces selected from a surface of the gasket to receive compressive force from the sealing member, a surface of the gasket to receive compressive force from the battery can wall, a surface of the sealing member to apply compressive force to the gasket and a surface of the opening peripheral battery can wall to apply compressive force to the gasket.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealed structure using a gasket in a sealed battery and the gasket itself.

[0002]

2. Description of the Related Art A sealed battery is one in which a power generating element is sealed in a battery can. For example, a dry battery is a well-known embodiment. The power generation element referred to here is an electrochemical element of a battery for performing power generation and charge / discharge. FIG. 4 is a schematic diagram showing a conventional general sealing structure when a power generation element is sealed in a cylindrical battery can. As shown in the figure, the conventional general sealed structure is similar to the case where the mouth of the container is closed with a lid.
In this structure, the opening of the battery can 21 is closed by a sealing member 22. The battery can 21 is a tubular body having one end face as an opening and the other end face as a bottom face, and the sealing member 22 is fitted into the opening of the battery can 21.

As shown in the figure, the battery can wall 21A around the opening is bent so as to include a "U-shaped" cross-sectional shape, and that portion grips the outer peripheral edge 22a of the sealing member over the entire circumference. . In this specification, “grabbing” is basically a “clamping” state on two surfaces, but the third surface on the inner surface of a portion having a “U-shaped” cross-sectional shape is also included. It means the state of being added and held. This battery can wall 21A
Is gripping the outer peripheral edge 22a of the sealing member, that is,
A gasket 23 is used so as to be interposed between the joining surfaces of the battery can wall 21A and the outer peripheral edge 22a of the sealing member, thereby obtaining high sealing performance.

[0004] The sealing member referred to in the present specification can be regarded as one lid for closing the opening of the battery can when the sealed battery is completed, but it is not usually a single member but the outermost outer surface. In addition to the terminal plate, various plate members for a safety structure that releases internal gas when the internal pressure rises are often laminated on the inner side of the terminal plate. In the present specification, these are not divided in detail, and the one in which one or more components are gathered at the opening of the battery can to form a lid is called a sealing member. FIG. 4 illustrates the sealing member 22 as a single member.

[0005]

In the sealed structure of a sealed battery as described above, conventionally, the surface 23a of the gasket surface which receives a compressive force from the sealing member in order to increase the sealing performance of the gasket to a desired value. (The inner surface of the section of the gasket in FIG. 4 having a “U-shape”), and the surface 23b receiving the compressive force from the battery can wall (the outer surface of the portion of the gasket in the section of “U-shape” in FIG. 4) ) Was further coated with a sealant such as asphalt.

The present inventors have focused on reducing the cost of this step by eliminating the step of further applying the sealant to the gasket. It is an object of the present invention to provide a sealed structure and a gasket for the sealed battery which can further improve the sealing performance of the gasket itself without further applying a sealing agent to the gasket surface. .

[0007]

SUMMARY OF THE INVENTION The present invention has the following features. (1) A sealed structure of a sealed battery in which the opening of the battery can is sealed with a gasket interposed therebetween and the inside of the battery is sealed with a sealing member, wherein the gasket has a sealing member and a battery can wall around the opening around the entire opening. A gasket surface having an annular base portion that can be interposed between the gasket and receiving a compressive force from the sealing member;
The surface is selected from a gasket surface which receives a compressive force from the battery can wall, a sealing member surface which applies a compressive force to the gasket, and a battery can wall surface around an opening which applies a compressive force to the gasket.
A sealed structure for a sealed battery, wherein a mountain-shaped projection is formed on the above-described surface and extends in a closed ring along the entire periphery of the opening.

(2) The above-mentioned structure is such that the plate-shaped sealing member is fitted into the opening of the battery can, and the outer peripheral edge of the sealing member is gripped over the entire periphery of the battery can wall around the opening via a gasket. The sealed structure of the sealed battery according to (1).

(3) A gasket interposed between a sealing member for closing an opening of a battery can of a sealed battery and a battery can wall around the opening and used to seal the inside of the battery. It has an annular base portion that can be interposed between the member and the battery can wall around the opening, and receives a compressive force from the sealing member and / or a compressive force from the battery can wall among the surfaces of the base portion. A gasket, characterized in that a mountain-shaped projection is formed on a surface of the base portion so as to form a closed ring along the entire circumference of the annular shape of the base portion.

(4) The plate-like sealing member is fitted into the opening of the battery can, and the outer peripheral edge of the sealing member is gripped by the battery can wall around the opening over the entire circumference. The gasket according to the above (3), which is used for being interposed therebetween.

(5) In the state where the gasket is in use, the battery can wall is outside the sealing member in the cross-sectional shape of the base portion when the gasket is cut at one place so that the annular shape is opened. The gasket according to the above (4), wherein a cross-sectional shape of a portion interposed in a portion gripping the peripheral edge portion is “U-shaped”.

(6) When the gasket is not used, the gasket is cut off at one place so that the annular shape is opened, and the battery can wall is out of the sealing member. (4) The gasket according to the above (4), wherein a cross-sectional shape of a portion to be interposed in a portion that grips the peripheral edge portion is “angle”.

Hereinafter, when describing the cross-sectional shape of the base portion of the gasket, "the cross-sectional shape of the base portion when the gasket is cut at one place so as to open the annular shape of the base portion of the gasket" is simply referred to as "the cross-sectional shape of the gasket." This is referred to as “cross-sectional shape”.

Similarly, when explaining the cross-sectional shape of the battery can wall, when the battery can is cut along the central axis, one of the cross sections of the facing wall portions appearing on both sides of the central axis. The shape of the cross section of the wall portion is referred to as “the cross-sectional shape of the battery can wall”. For example, in the example of FIG. 1, the cross-sectional shape of the battery can wall at the portion where the sealing member is gripped is “U-shaped”.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a closed structure according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an example of the closed structure of the present invention. The structure of caulking the battery can wall and the sealing member in the example of FIG. 4 is the same as that of the conventional example of FIG. 4, and FIG. 1 particularly shows a cross section of the gasket and its periphery in an enlarged manner. As in the conventional example of FIG.
Is fitted in the opening. Battery can wall 1A around opening
Is bent over the entire circumference so that the cross-sectional shape becomes “U-shaped”, and the inside of the “U-shaped” grips the entire outer circumference of the sealing member. Gasket 3
Is disposed between the battery can wall 1A and the sealing member 2 over the entire circumference of the opening, and has an annular base portion 4 along the opening.

In the sealing structure shown in FIG. 1, at a portion where the gasket 3 is interposed between the sealing member 2 and the battery can wall 1A, at least one surface selected from the following surfaces is provided. Protrusions are provided along the circumference in a mountain-like manner.
The projections are connected to each other in a closed ring around the periphery of the opening. The surfaces 4a, 4b, 4c of the base part 4 of the gasket, which are subjected to a compressive force from the sealing member. The surfaces 4d, 4e, 4f of the base part 4 of the gasket which are subjected to a compressive force from the battery can wall. Surfaces 2a and 2 of the sealing member for applying a compressive force to the gasket
b, the side surface of the sealing member contacting the surface 4b of the base part 4 of the gasket. Surfaces 1a, 1b, 1c of the battery can wall around the opening that applies a compressive force to the gasket.

In the example of FIG. 1, a projection 5 is provided on a surface 4f which is one of the surfaces of the base portion 4 which receives the compressive force from the battery can wall 1A. The protruding portion 5 extends in a mountain range in a ring shape along the ring-shaped shape of the base portion 4 and is closed by making one round. In FIG. 1, for explanation,
The projection 5 is shown as not being crushed.

By providing the projection on one or more surfaces selected from the above-mentioned surfaces, the compressive force generated when the battery can wall grips the sealing member over the gasket is concentrated on the projection. Therefore, when the projection is provided on the gasket as shown in FIG. 1, the projection is sufficiently bent. Further, when the projection is provided on the battery can wall as in the projection 1m in FIG. 2, or when the projection is provided on the sealing member as in the projection 2m, the projection sufficiently digs into the gasket. That is, in any case, the protrusions are sufficiently adhered to the mating surface, and the sealing property is improved.

The cross-sectional shape of the projection may be any shape as long as it can receive the compressive force intensively, and is not limited. Preferred shapes include a semicircle, a rectangle, and a triangle. The size of the cross-sectional shape of the projection is the same regardless of whether the projection is provided on any of the gasket, the battery can, and the sealing member. It is preferably about 0.2 mm to 0.4 mm.

As a method of providing a projection on a component, a projection-shaped member connected in a mountain range may be separately formed and joined to form a projection. However, a mold for a component (for example, a molding die for a gasket, a battery can, etc.) In such a case, a metal mold or the like is partially changed to form the protrusions, whereby low-cost and effective sealing properties can be obtained.

Next, the gasket which can constitute the closed structure of the present invention will be described. As shown in the example of FIG.
The gasket 3 of the present invention is interposed between the battery can wall 1A and the sealing member 2 over the entire periphery of the opening, and has an annular base portion 4 along the opening. Of the surface of the base portion 4, the projections 5 are provided on the surface that receives the compressive force from the sealing member and / or the surface that receives the compressive force from the battery can wall (the example in FIG. 1). As described above, the protruding portion 5 extends in a mountain range like an annular shape along the annular shape of the base portion 4 and is closed by one round.

By providing a projection on the base portion of the gasket, the compressive force received by the gasket sandwiched between the sealing member and the battery can wall concentrates on the projection, and the projection is sufficiently engaged with the mating surface. To improve sealing.

As shown in FIG. 1, of the surface of the base portion, the surface on which the protrusions can be provided is the surface 4d, 4e, 4f and the sealing member 2 which receive the compressive force from the battery can wall 1A. 4a, 4b, 4c
Is mentioned. One or more arbitrary surfaces may be selected from these and the projections may be provided. Among these, the surfaces that receive particularly strong compression include the surfaces 4a, 4c, 4d, and 4f.

In the case of the joint structure of the sealing member and the battery can wall as shown in FIG. 1, the gasket is interposed over the entire "U-shaped" cross-sectional portion where the battery can wall grips the sealing member. It is preferable in terms of hermeticity. Therefore, in that case, it is preferable that the shape of the base portion of the gasket has a portion that can have a “U-shaped” cross-sectional shape. However,
The portion of the cross-sectional shape of the gasket that has the “U-shape” does not necessarily have to be “U-shape” in the state of a single product that is not used, as shown in FIG.
The cross-sectional shape may be such that the assemblability up to the step of bending and caulking the battery can wall is good.

FIG. 3 is a sectional view showing an example of the gasket according to the present invention in a single piece state. Illustration of chamfers and rounds at corners and corners is omitted. The example of FIG.
Is an example of the shape of the gasket used in the hermetic structure of the present invention. In the gasket cross-sectional shape, a portion having a “U-shaped” cross-sectional shape is surrounded by a circle A formed by a thin line, as shown in “Yamagata (L-shape)”. , Or inverted L-shape) ". Such a shape facilitates the work of incorporating the gasket and the sealing member into the battery can. In the gasket of FIG. 3, the inner surface 4 g of the cross-sectional “angle” portion is bent inward together with the battery can wall to become the concave surfaces 4 a and 4 b of the “U-shaped” cross-sectional shape in FIG. 1. In the gasket shown in FIG. 3, when bent, the surfaces 4a, 4c, 4d, 4f of FIG.
Are provided with projections 5a, 5c, 5d, and 5f.

The shape and size of the projection provided on the gasket are as described above. As a material of the gasket, a material similar to a conventional gasket, such as polypropylene or polyethylene, may be used.

The sealed battery to which the sealed structure or gasket of the present invention is applied is not limited, but typical examples include those having an arbitrary shape such as a cylindrical type (including a button type) and a square type. In these types of sealed batteries, a commonly used battery can is a cylindrical / prismatic tubular body (including a button type) having one end face open and the other end face as a bottom face. Generally, a structure is used in which the sealing member closes the sealing member like a lid and seals it. In the case of such a sealed battery, as shown in FIG. 1, the sealing structure of the sealing member and the battery can wall around the opening are such that the battery can wall has a “U-shaped” cross-sectional shape. Caulked structure.

Although the sealed structure and gasket according to the present invention are useful for all sealed batteries, high-capacity lithium-ion secondary batteries used as rechargeable power sources for notebook computers, mobile phones, portable video cameras, etc. This is particularly useful for improving the tightness of the battery.

[0029]

EXAMPLE A sealing structure shown in FIG. 1 was provided to a sealing portion (= positive electrode terminal portion) of a cylindrical lithium ion secondary battery.
The sealing member has an outer diameter of about 12 mm and a total thickness of the outer peripheral edge is about 1.8 mm. The wall around the opening of the battery can was bent over the entire circumference so as to have a “U-shaped” cross-sectional shape, and the entire periphery of the sealing member was crimped so as to be gripped via a gasket to form a sealed structure. . The gasket is made of polypropylene and has a “U-shape” along with the bending of the battery can wall.
The section having the cross-sectional shape of “1” was a “mountain-shaped” cross-sectional shape in a single product state. The projection was provided on a surface 4f on the base portion 4 of the gasket 3, as shown in FIG. The cross-sectional shape of the protrusion was semicircular and the radius was 0.2 mm.

The sealing part of the lithium ion secondary battery is immersed in water, an inert gas is fed into the inside from the bottom of the can, and the gasket is sealed by observing the occurrence of air bubbles from the sealing part while increasing the pressure. As a result of testing the sealing performance, it was confirmed that the sealing performance was equivalent to that of a conventional gasket accompanied by the application of a sealant.

[0031]

As described above, the sealing structure of the sealed battery according to the present invention or the gasket used therefor further improves the sealing performance of the gasket itself without further applying a sealing agent to the gasket surface. And assembling became easier.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an example of a sealed structure of a sealed battery according to the present invention. The hatching indicating the cross section is omitted.

FIG. 2 is a diagram schematically showing another example of the sealed structure of the sealed battery according to the present invention. The hatching indicating the cross section is omitted.

FIG. 3 is a sectional view showing an example of a gasket according to the present invention in a single item state. Only one side of the center line is shown.

FIG. 4 is a schematic view showing a general sealed structure in a conventional sealed battery. Only the cross section of the gasket is hatched to clearly show the sections of the members.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery can 1A Battery can wall 2 Sealing member 3 Gasket 4 Base part of gasket 5 Projection

Continued on the front page (72) Inventor Kenji Kawamura 4-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Cable Industry Co., Ltd. Itami Works (72) Inventor Atsushi Atsushi Gozen 4-3-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Cable Industries Itami Inside the factory (72) Inventor Munehiro Nakata 4-3 Ikejiri, Itami-shi, Hyogo Prefecture Mitsubishi Electric Corporation Itami Works

Claims (6)

[Claims] 1. A sealed structure of a sealed battery in which the opening of a battery can is sealed with a sealing member with a gasket interposed between the opening of the battery can, wherein the gasket is formed over the entire periphery of the opening and the sealing member and the battery can around the opening. A surface of a gasket that has an annular base portion that can be interposed between the wall and a gasket surface that receives a compressive force from a sealing member, a surface of a gasket that receives a compressive force from a battery can wall,
One or more surfaces selected from a surface of the sealing member that applies a compressive force to the gasket and a surface of the battery can wall around the opening that applies a compressive force to the gasket are connected in a closed ring along the entire circumference around the opening. A sealed structure for a sealed battery, wherein a mountain-shaped projection is provided. 2. A structure in which a plate-shaped sealing member is fitted into an opening of a battery can, and the outer peripheral edge of the sealing member is gripped by a gasket around the opening over the entire periphery thereof via a gasket. The sealed structure of the sealed battery according to claim 1. 3. A gasket interposed between a sealing member for closing an opening of a battery can of a sealed battery and a battery can wall around the opening and used to seal the inside of the battery, wherein the sealing member covers the entire periphery of the opening. And a ring-shaped base portion that can be interposed between the opening and the battery can wall around the opening, and a surface of the base portion that receives a compressive force from the sealing member and / or a surface that receives a compressive force from the battery can wall. A gasket, characterized by being provided with a mountain-shaped projection that extends in a closed ring along the entire circumference of the annular shape of the base portion. 4. A plate-like sealing member is fitted into the opening of the battery can, and a portion between the sealing member and the battery can wall is gripped by the battery can wall around the opening over the entire periphery of the sealing member. 4. The gasket according to claim 3, wherein the gasket is used to interpose a gasket. 5. When the gasket is used, the outer peripheral edge of the sealing member of the cross-sectional shape of the base portion when the gasket is cut at one place so that the annular shape is opened. 5. The gasket according to claim 4, wherein the cross-sectional shape of the portion interposed in the portion that grips the portion is "U-shaped." 6. When the gasket is not in use, the battery can wall is the outer peripheral edge of the sealing member in the cross-sectional shape of the base portion when the gasket is cut at one place so that the annular shape is opened. 5. The gasket according to claim 4, wherein a cross-sectional shape of a portion to be interposed between the portion for gripping the portion is "angle".