JP2001102012A - Enclosure for thin type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provided an enclosure for thin type battery which may eliminate positioning of the location of lead wires and prevent a short circuit relative to the lead wire. SOLUTION: A sheet material 1 includes a sealant layer 8 and a metal layer 9. The sheet material 1 is fold such that both end portions thereof are bent inwardly in two steps toward the sealant layer 8, the periphery of the sweet material beside the fold part 2 is heat-sealed. The heat-sealed portion between the upper and lower sealant layers 8 forms an exit of the lead wires 6, in which a part of the sheet material 1 corresponding to the exit of the lead wires excludes the metal layer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin battery bag for housing a power generating element for a thin battery such as a lithium ion secondary battery (LIB) or a lithium polymer battery (LPB).

[0002]

2. Description of the Related Art With the recent development of various electronic devices, there is an increasing need for downsizing and space saving of electronic devices, and further thinning and lightening of thin batteries (sheet batteries) used for these devices. Is required. To meet such needs, a lithium ion secondary battery using a gel polymer electrolyte has been put into practical use. In addition, an intrinsic polymer battery in which the electrolyte is completely polymerized is in the development stage.

FIGS. 4 and 5 show examples of the structure of a lithium ion secondary battery using the above-mentioned gel polymer electrolyte. In the figure, 21 is a positive electrode current collector (aluminum foil), 22 is a positive electrode (a lithium-containing composite oxide such as lithium cobalt oxide), 23 is an isolating material (a polymer electrolyte plasticized with a solvent), and 24 is a negative electrode (charcoal). ) And 25 are negative electrode current collectors (copper foils),
One is stored. Since such a lithium ion secondary battery has a low risk of liquid leakage, the power generation element 37
Can be stored in a thin laminate. In the structural example shown in FIG. 5, a polypropylene sealant layer 38 and an aluminum foil metal layer 3
9, a four-layer laminate material having a protective layer 40 made of polyamide and a protective layer 41 made of polyethylene terephthalate is used. In Japanese Patent Application Laid-Open No. 9-7636, a three-layer laminate of a polyethylene layer, an aluminum foil layer, and a polyethylene layer is used. 33, 3
4 and 35 are side edges of the storage means 31 to be heat-sealed;
Reference numeral 36 denotes a lead wire for taking out an electrode. The lead wire 36 made of aluminum foil is used for the positive electrode, and the lead wire 36 made of copper foil is used for the negative electrode.

A part of the lead wire 36 is covered with an insulating resin 42 at its outer periphery in order to prevent a short circuit with the metal layer 39 of the storage means 31. A portion between the surfaces of the laminate material to be heat-sealed serves as an outlet for the lead wire 36, and the insulating resin 42 portion of the lead wire 36 is positioned in this outlet.

[0005]

However, in a thin battery such as the above-mentioned lithium ion secondary battery, when heat-sealing the laminate, the insulating resin 4
Since it is necessary to position the two parts at the part to be heat-sealed, there is a problem that the production speed cannot be increased. In addition, the above positioning is not perfect,
There is a possibility that the portion of the insulating resin 42 and the portion to be heat-sealed may be shifted. When this shift occurs, the lead wire 36
And the metal layer 39 of the storage means 31 may be short-circuited.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a thin battery bag that does not require positioning of a lead wire and does not cause a short circuit with the lead wire.

[0007]

In order to achieve the above object, a thin battery bag according to the present invention is formed into a bag by heat-sealing a predetermined portion of a laminate comprising a metal layer and a sealant layer. In the formed thin battery power storage element storage bag body, a required portion of the heat-sealed portion is formed at a lead wire outlet, and the laminate material portion corresponding to the outlet is formed at The configuration is such that no metal layer is provided.

That is, in the thin battery bag of the present invention, since the metal layer is not provided on the portion of the laminate material corresponding to the lead wire outlet, short-circuiting between the metal layer and the lead wire does not occur. . Therefore, an insulating resin portion for preventing short circuit is not required in the lead wire, and when the outlet is heat-sealed, there is no need to position the insulating resin portion of the lead wire. As a result, the production speed of the thin battery can be increased.

Next, the present invention will be described in detail.

The thin battery bag of the present invention is made of a laminate made of a metal layer and a sealant layer.

As the material of the metal layer of the laminate material constituting the above-mentioned thin battery bag, aluminum, aluminum alloy, copper, copper alloy, and the like obtained by rolling, electrolysis and the like can be used.
Iron, stainless steel, titanium, titanium alloy and the like are used, and are formed into various forms such as foil. And the thickness is 5-10
It is preferable that the distance is set in the range of 0 μm. When the thickness is less than 5 μm, pinholes are liable to be generated in the metal layer, and the gas barrier property and the water-shielding property of the laminated material are reduced.
If it exceeds 00 μm, it is disadvantageous for thinning and flexibility of the thin battery bag.

The material of the sealant layer is as follows:
Polypropylene, polyethylene, polyester, polyacrylonitrile, ethylene vinyl acetate copolymer (EV
A), polyvinyl alcohol (PVA), modified polypropylene, modified polyethylene, polyvinyl acetate, polyvinyl acetate and the like are used. In particular, modified polypropylene is preferable in terms of insulation between the lead wires sealed by the sealant layer, insulation between the metal layer inside the laminate material and the power generation element, and adhesion to the lead wires. As the modified polypropylene, maleic acid-modified polypropylene, acryl-modified polypropylene, epoxy-modified polypropylene, carboxylic acid-modified polypropylene, silanol-modified polypropylene and the like are used. The thickness is preferably set in the range of 5 to 1000 μm. When the thickness is less than 5 μm, the air-tightness (embedding property of the sealant) of the electrode seal portion is reduced to 1000 μm.
If the ratio exceeds the above range, it is disadvantageous to reduce the thickness of the thin battery bag.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of a thin battery bag according to the present invention. In this embodiment,
The thin battery bag is a three-sided seal (semi-folded seal) type bag. After one sheet material 1 is folded in two, three side edges 3, 4, and 5 other than the fold line 2 are formed. Is formed by heat sealing (sealing). Then, the side edges 3, 4, which are heat-sealed,
The power generating element 7 is housed in the thin battery bag in a state where the lead wire 6 is drawn out from one side edge portion (side edge portion facing the fold 2 in the figure) 4 out of 5. That is,
The lead wire 6 is drawn out of the thin battery bag from between the surfaces to be heat-sealed (between the sealant layers 8 to be described later).

The sheet material 1 constituting the bag is a laminated material having a thickness of about 0.1 mm which is composed of a four-layered laminate, and a maleic acid-modified polypropylene sealant layer 8 and an aluminum foil are arranged in this order from the inside of the bag. A metal layer 9, a protective layer 10 made of polyamide, and a protective layer 11 made of polyethylene terephthalate. The metal layer 9 is not disposed on the portion 4a of the sheet material 1 (the left and right end portions of the sheet material 1 shown in FIG. 3) which becomes the side edge portion 4 corresponding to the outlet of the lead wire 6. .

The power generating element 7 is such that the lead wire 6 is not covered with the insulating resin 42 (see FIG. 5) for short circuit prevention, and the other parts are the conventional power generating element 37 shown in FIG. Is the same as And the size is, as an example,
It is about 40 mm x 80 mm x 4 mm (thickness).

A thin battery (a thin battery bag housing the power generating element 7) is manufactured as shown in FIG. That is, first, one sheet material 1 in which the metal layer 9 is not disposed on the left and right end portions 4a is prepared. Next, the power generating element 7 is arranged so that the lead wire 6 projects outside the left side of the sheet material 1. Next, sheet material 1
At the fold line (center line) 2 to sandwich the power generation element 7. After that, 3 other than the fold 2 of the overlapped sheet material 1
The three side edges 3, 4, 5 (see FIG. 1) are heat sealed. Thus, a thin battery bag housing the power generating element 7 as shown in FIGS. 1 and 2 is manufactured.

According to the above embodiment, since the metal layer 9 is not disposed on the portion 4a of the sheet material 1 corresponding to the outlet of the lead wire 6, short-circuit between the metal layer 9 and the lead wire 6 is prevented. Does not happen. Therefore, the insulating resin 42 (see FIG. 5) for preventing short circuit is not required for the lead wire 6, and the insulating resin 42 (see FIG. 5) of the lead wire 6 is positioned when the outlet is heat-sealed. You don't have to. As a result, the production speed of the thin battery can be increased.

Further, the insulating resin 42 for preventing short-circuit is provided.
(See FIG. 5) becomes unnecessary, so that the outlet for the lead wire 6 becomes small, and the sealant is buried well during heat sealing. Therefore, the heat seal at the outlet of the lead wire 6 is more reliable, and the airtightness of the heat seal portion is improved.

In the above embodiment, the lead wire 6 of the positive electrode is made of aluminum foil and the lead wire 6 of the negative electrode is made of copper foil, as in the prior art. However, the present invention is not limited to this. Alternatively, the lead wire 6 of the positive electrode may be made of titanium foil or an alloy foil of titanium and aluminum, or the lead wire 6 of the negative electrode may be made of a nickel foil or an alloy foil of nickel and copper.

Further, in the above-described embodiment, the thin battery bag is a three-way seal (half-fold seal) type bag. However, the present invention is not limited to this, and two folds 2 are provided in parallel. An envelope seal (pillow) type bag, a four-sided seal type bag in which two sheet materials 1 are stacked, or the like may be used.

[0022]

As described above, according to the thin battery bag of the present invention, since the metal layer is not provided in the portion of the laminate material corresponding to the lead wire outlet, the metal layer and the lead No short circuit with the wire. Therefore, an insulating resin portion for preventing short circuit is not required in the lead wire, and when the outlet is heat-sealed, there is no need to position the insulating resin portion of the lead wire. as a result,
The production speed of thin batteries can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a thin battery bag according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the thin battery bag.

FIG. 3 is an explanatory view showing a method for producing the thin battery bag.

FIG. 4 is a perspective view showing a conventional lithium ion secondary battery.

FIG. 5 is a cross-sectional view showing a structural example of a conventional lithium ion secondary battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet material 2 Fold 6 Lead wire 8 Sealant layer 9 Metal layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 AA04 AA06 CC02 CC06 CC10 DD05 DD06 DD13 EE04 FF02 FF04 HH02 5H029 AJ14 AL12 AM16 BJ04 CJ03 CJ05 DJ02 DJ03 DJ05 DJ14 EJ01 EJ12 HJ12

Claims (1)

[Claims] Claims 1. A bag for accommodating a thin battery power generation element formed in a bag shape by heat sealing a predetermined portion of a laminate material comprising a metal layer and a sealant layer,
A required portion of the heat-sealed portion is formed at an outlet of a lead wire, and the metal layer is not provided on a portion of the laminate material corresponding to the outlet, for a thin battery. Bag.