JP5347389B2 - Power storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage device capable of suppressing deterioration of a sheath and reducing bulkiness. <P>SOLUTION: In the laminate type storage device 1 in which a laminate type storage device is equipped with a storage element 100 and the sheath, the sheath includes a first laminate film 110 and a second laminate film 120, an inner face layer 111 and an inner face layer 121 are heat-welded and fixed at the surrounding of the storage element 100, and the storage element 100 is sealed inside the sheath, at the end part of the second laminate film 120, a notch 124 to penetrate the second laminate film 120 is formed, the end part of the first laminate film 110 has a folding back part 114 folded back to cover the end part of the second laminate film 120 wherein the notch 124 is formed, and in the folded back part 114, an outer face layer 123 and the inner face layer 111 are opposed, and the inner face layers 111 are opposed by pinching the second laminate film 120, and heat-welded through the notch 124. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a power storage device such as a lithium ion secondary battery, a lithium secondary battery, and a polymer secondary battery, and more particularly to a power storage device including an outer packaging material made of a flexible film that stores a power storage element. is there. In this specification and claims, the “storage device” includes not only a lithium ion secondary battery, a lithium secondary battery, and a polymer secondary battery but also an electric double layer capacitor.

  2. Description of the Related Art Conventionally, for example, batteries such as lithium ion secondary batteries have been increasingly demanded for downsizing, weight reduction, thickness reduction, shape freedom, and the like with the expansion of various applications.

  Therefore, in order to meet such demands, a laminate film having a multilayer structure has been conventionally used to form a flexible outer packaging material that accommodates battery elements. The laminate film is composed of an inner surface layer facing the battery element (unit cell), an intermediate layer, and an outer surface layer facing the outside. The inner surface layer is made of, for example, a thermoplastic resin excellent in electrolytic solution resistance and heat sealability, such as polyethylene and polypropylene. An intermediate | middle layer consists of metal foil excellent in flexibility and intensity | strength, such as aluminum foil, for example. An outer surface layer consists of insulating resin excellent in electrical insulation, such as a polyamide-type resin, for example.

  A structure of a battery (hereinafter referred to as a laminate type battery) in which a battery element is housed in an outer packaging material made of such a laminate film is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-250515 (Patent Document 1).

  FIG. 5 is a cross-sectional view showing a part of a cross section of a conventional laminated battery.

As shown in FIG. 5, in the conventional laminated battery 9 described in Japanese Patent Application Laid-Open No. 2001-250515 (Patent Document 1), the battery element 900 is composed of an outer packaging material 910 and an outer packaging material 920 formed by a laminated composite material. It is covered. The peripheral portion 911 of the outer packaging material 910 and the peripheral portion 921 of the outer packaging material 920 are joined by thermal welding to form a joining piece portion 930. The joint piece 930 is bent along the side surface of the battery 9 and bonded to the side surface of the outer packaging material 920 that covers the side surface of the battery 9 with an adhesive 940. In this way, by bending the joint piece 930 between the outer packaging material 910 and the outer packaging material 920 along the side surface of the battery 9 and bonding it to the outer packaging material 920, the volume of the battery 9 can be reduced.
JP 2001-250515 A

  However, in the conventional laminate type battery described in Japanese Patent Laid-Open No. 2001-250515 (Patent Document 1), an adhesive is used to adhere the joining piece 930 to the surface of the outer packaging material 920 that covers the side surface of the battery 9. Therefore, an adhesive material cost and an adhesive application process are required, which increases costs. Further, the outer surface layer of the outer packaging material 920 formed of the laminated composite material is deteriorated by the adhesive, and there is a concern that the long-term reliability of the battery 9 may be reduced.

  In view of the above, an object of the present invention is to provide an electricity storage device that can suppress deterioration of the outer packaging material and reduce the bulk with a small number of steps.

An electricity storage device according to the present invention includes an electricity storage element and an outer packaging material made of a flexible film that houses the electricity storage element. The outer packaging material includes a first outer packaging portion having a first inner surface layer facing the power storage element, a second inner surface layer facing the first inner surface layer with the power storage element interposed therebetween, and an outer side of the second inner surface layer. And a second outer packet part having an outer surface layer covering the outer surface. The first inner surface layer and the second inner surface layer are fixed by being thermally welded around the power storage element, and the power storage element is sealed inside the outer packaging material. In the electricity storage device configured as described above, a through-hole penetrating the second outer packet part is formed inside the edge of the second outer packet part. The edge part of the 1st outer packet part has the bending part bent so that the edge part of the 2nd outer packet part in which the through-hole was formed was covered. In the bent portion, the outer surface layer of the second outer packet portion and the first inner surface layer of the first outer packet portion face each other, and the first inner surface layer of the first outer packet portion sandwiching the second outer packet portion The two are opposed to each other and are thermally welded through the through holes.

  In the periphery of the electricity storage element, the first inner surface layer and the second inner surface layer are thermally welded and fixed. In this state, an excess portion is generated in the outer packaging material around the power storage element. Then, the surplus part of an outer packaging material can be made small by bending the 1st outer packet part so that the edge part of a 2nd outer packet part may be covered with a 1st outer packet part.

  When the first outer packet part is folded so as to cover the end of the second outer packet part with the first outer packet part, the outer surface layer of the second outer packet part and the first outer packet layer are formed on the outer surface layer side of the second outer packet part. The first inner surface layer of the outer packet part is opposed. The outer surface layer of the second outer packet part and the first inner surface layer of the first outer packet part are not thermally welded. Therefore, the bent part of the first outer packet part cannot be fixed by heat welding to the outer surface layer of the second outer packet part. However, in the bent part of the first outer packet part, the first inner surface layers are opposed to each other with the second outer packet part interposed therebetween. A through hole is formed in the second outer packet part covered with the bent part. The first inner surface layers of the first outer packet part sandwiching the second outer packet part are thermally welded through the through hole. Thus, since the first inner surface layers of the first outer packet part are thermally welded and fixed with the second outer packet part sandwiched therebetween, the shape of the folded outer packet material can be stabilized.

  In addition, as described above, since an excess portion of the outer packaging material can be bent and thermally welded and fixed without using an adhesive or a tape, the outer packaging material is not deteriorated by the adhesive or the adhesive of the tape. In addition, since the step of bending the end portion of the first outer packet portion and the step of heat welding can be performed at the same time, the excess portion is bent and applied with an adhesive or bonded with a tape. In comparison, a power storage device having a small volume can be manufactured with a small number of steps.

  By doing in this way, the electrical storage device which can suppress deterioration of an outer packaging material, can improve long-term reliability, and can reduce a bulk with few processes can be provided.

  As described above, according to the present invention, it is possible to provide an electricity storage device that can suppress deterioration of the outer packaging material, increase long-term reliability, and reduce the bulk with a small number of steps.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows, as an embodiment of the present invention, a front view (A) showing the whole of a laminate-type electricity storage device (one example is a laminate-type battery) and a laminate shown in FIG. Sectional view (B) when the type electricity storage device is viewed from the direction indicated by line BB, and perspective view when the laminate type electricity storage device shown in FIG. 1 (A) is viewed from the direction of the lead terminal (C) It is.

  As shown in FIGS. 1A to 1C, the laminate-type electricity storage device 1 covers and accommodates an electricity storage element 100 (for example, a unit cell or battery element) 100 and the electricity storage element 100. Electrically connected to the first laminate film 110 as the first outer packaging portion of the outer packaging material made of a flexible film, the second laminate film 120 as the second outer packaging portion, and the positive electrode and the negative electrode of the electricity storage element 100, respectively. The positive electrode lead terminal 103 and the negative electrode lead terminal 104 are formed to protrude from the first laminate film 110 and the second laminate film 120.

  The power storage element 100 includes a positive electrode current collector, a positive electrode active material applied to the positive electrode current collector, a negative electrode current collector, a negative electrode active material applied to the negative electrode current collector, and a solid electrolyte. A positive electrode lead terminal 103 is connected to the positive electrode uncoated portion 101 of the positive electrode current collector, and a negative electrode lead terminal 104 is connected to the negative electrode uncoated portion 102 of the negative electrode current collector.

  The first laminate film 110 includes an inner surface layer 111, an intermediate layer 112, and an outer surface layer 113 facing the outside as a first inner surface layer facing the power storage element 100. The second laminate film 120 includes an inner surface layer 121, an intermediate layer 122, and an outer surface layer 123 facing the outside as a second inner surface layer facing the power storage element 100. The inner surface layers 111 and 121 of the first laminate film 110 and the second laminate film 120 are made of, for example, a thermoplastic resin excellent in electrolytic solution resistance and heat sealability, such as polyethylene and polypropylene. The intermediate layers 112 and 122 are made of a metal foil having excellent flexibility and strength, such as an aluminum foil. The outer surface layers 113 and 123 are made of, for example, an insulating resin excellent in electrical insulation, such as a polyamide-based resin. In this embodiment, as an example, the inner surface layers 111 and 121 are made of polypropylene, the intermediate layers 112 and 122 are made of aluminum foil, and the outer surface layers 113 and 123 are made of nylon.

  The first laminate film 110 has a bent portion 114 that is bent so as to cover the end portion of the second laminate film 120. At the end of the second laminate film 120, a notch 124 is formed as a through hole. The notch 124 is a hole that penetrates the second laminate film 120. The bent portion 114 of the first laminate film 110 is bent so as to wrap the end portion of the second laminate film 120 and the notch 124 formed at the end portion. Thus, the notch 124 of the second laminate film 120 is covered with the first laminate film 110.

  The first laminate film 110 and the second laminate film 120 are accommodated so as to sandwich the power storage element 100, and the inner surface layer 111 of the first laminate film 110 and the inner surface layer 121 of the second laminate film 120 are thermally welded. As a result, the peripheral portion of the electricity storage element 100 is fixed. The positive electrode lead terminal 103 and the negative electrode lead terminal 104 are drawn to the outside from a portion where the outer peripheral edge portions of the first laminate film 110 and the second laminate film 120 are thermally welded and sealed.

  FIG. 2 is a diagram showing a state in each process of manufacturing the laminate type electricity storage device of the present invention.

  As shown in FIG. 2A, first, the electricity storage element 100 is placed on the first laminate film 110. Next, as shown in FIG. 2B, the second laminate film 120 is placed on the power storage element 100 placed on the first laminate film 110. A plurality of notches 124 are formed at the end of the second laminate film 120. At this time, the inner surface layer of the first laminate film 110 and the inner surface layer of the second laminate film 120 face each other, and the power storage element 100 is sandwiched between the inner surface layers. The bent portion 114 of the first laminate film 110 protrudes from the end edge of the second laminate film 120. The length L1 of the bent portion 114 protruding from the edge of the second laminate film 120 is formed to be longer than the distance L2 from the edge of the second laminate film 120 to the notch 124. Next, the bent portion 114 of the first laminate film 110 is bent.

  FIG. 3 is a perspective view (A) showing a part of the end of the laminate-type electricity storage device before folding the bent portion of the first laminate film, and a part of the end of the laminate-type electricity storage device after bending. It is a perspective view (B) shown.

  As shown in FIG. 3A, a second laminate film 120 is placed on the first laminate film 110 at the end of the laminate power storage device. The first laminate film 110 and the second laminate film 120 are overlapped so that the inner surface layers 111 and 121 face each other. A plurality of notches 124 are formed at the end of the second laminate film 120, and the inner surface layer 111 of the first laminate film 110 is exposed through the notches 124. The bent portion 114 of the first laminate film 110 protrudes from the end edge of the second laminate film 120.

  The first laminate film 110 and the peripheral portion from which the positive electrode lead terminal 103 and the negative electrode lead terminal 104 are drawn and the peripheral portion opposite to the peripheral portion from which the positive electrode lead terminal 103 and the negative electrode lead terminal 104 are drawn, respectively, The second laminate film 120 is thermally welded and sealed, and an electrolytic solution is charged.

  Next, as shown in FIG. 3B, when the folded portion 114 of the first laminate film 110 is folded, the end of the second laminate film 120 and the notch 124 formed at the end Is covered by the first laminate film 110. When the notch 124 is covered with the first laminate film 110 in which the bent portion 114 is bent, the inner surface layers 111 ((A) of FIG. 3) of the first laminate film 110 communicate with each other in the notch 124. . In this state, the first laminate film 110 and the second laminate film 120 are heat-welded at the bent portion 114.

  FIG. 4 is a cross-sectional view of the laminate type electricity storage device shown in FIG. 3B as viewed from the direction of the IV-IV line.

  As shown in FIG. 4, the bent portion 114 of the first laminate film 110 is bent, and the notch 124 at the end of the second laminate film 120 is covered with the first laminate film 110 and thermally welded. . At the end of the second laminate film 120, the inner surface layer 111 of the first laminate film 110 and the outer surface layer 123 of the second laminate film 120 face each other. Since the inner surface layer 111 and the outer surface layer 123 are not thermally welded, the shape of the folded outer packaging material cannot be stabilized as it is. However, in the notch 124, the inner surface layers 111 of the first laminate film 110 communicate with each other, and the inner surface layers 111 are thermally welded.

  In this way, the end portion of the second laminate film 120 is covered with the first laminate film 110, and the bent portion 114 of the first laminate film 110 is fixed on the end portion of the second laminate film 120. Therefore, the shape of the edge part of the 1st laminate film 110 and the 2nd laminate film 120 can be kept stable.

  As described above, the laminated power storage device 1 includes the power storage element 100 and the outer packaging material made of a flexible film that houses the power storage element 100. The outer packaging material includes a first laminate film 110 having an inner surface layer 111 facing the power storage element 100, an inner surface layer 121 facing the inner surface layer 111 with the power storage element 100 interposed therebetween, and an outer surface layer 123 covering the outside of the inner surface layer 121. And a second laminate film 120 having The inner surface layer 111 of the first laminate film 110 and the inner surface layer 121 of the second laminate film 120 are fixed by thermal welding around the electricity storage element 100, and the electricity storage element 100 is sealed inside the outer packaging material. . In the laminated power storage device 1 configured as described above, a notch 124 penetrating through the second laminate film 120 is formed at the end of the second laminate film 120. The end portion of the first laminate film 110 has a bent portion 114 that is bent so as to cover the end portion of the second laminate film 120 in which the notch 124 is formed. In the bent portion 114, the outer surface layer 123 of the second laminate film 120 and the inner surface layer 111 of the first laminate film 110 face each other, and the inner surface of the first laminate film 110 sandwiches the second laminate film 120. Layers 111 face each other and are thermally welded through cutouts 124.

  In the periphery of the electricity storage element 100, the inner surface layer 111 and the inner surface layer 121 are thermally welded and fixed. In this state, an excess portion is generated in the outer packaging material around the electricity storage element 100. Therefore, the excess portion of the outer packaging material can be reduced by folding the first laminate film 110 so that the end of the second laminate film 120 is covered with the first laminate film 110.

  When the first laminate film 110 is bent so that the end of the second laminate film 120 is covered with the first laminate film 110, the second laminate film 120 is formed on the outer surface layer 123 side of the second laminate film 120. The outer surface layer 123 and the inner surface layer 111 of the first laminate film 110 face each other. The outer surface layer 123 of the second laminate film 120 and the inner surface layer 111 of the first laminate film 110 are not thermally welded. Therefore, the bent portion 114 of the first laminate film 110 cannot be fixed by being thermally welded to the outer surface layer 123 of the second laminate film 120. However, in the bent portion 114 of the first laminate film 110, the inner surface layers 111 are opposed to each other with the second laminate film 120 interposed therebetween. A cutout 124 is formed in the second laminate film 120 covered with the bent portion 114. The inner surface layers 111 of the first laminate film 110 sandwiching the second laminate film 120 are thermally welded through the notches 124. Thus, since the inner surface layers 111 of the first laminate film 110 are thermally welded and fixed with the second laminate film 120 interposed therebetween, the shape of the folded outer packaging material can be stabilized.

  In addition, as described above, since an excess portion of the outer packaging material can be bent and thermally welded and fixed without using an adhesive or a tape, the outer packaging material is not deteriorated by the adhesive or the adhesive of the tape. Moreover, since the process of bending the edge part of the 1st laminated film 110 and the process of heat welding can be performed simultaneously, the excess part is folded and it adheres by applying an adhesive agent, or it adheres with a tape. Compared to the above, it is possible to manufacture the laminated electricity storage device 1 having a small volume with a small number of steps.

  By doing so, it is possible to provide the laminate-type electricity storage device 1 that can suppress deterioration of the outer packaging material, increase long-term reliability, and can reduce the volume with a small number of steps.

  The embodiment disclosed above should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above embodiments but by the scope of claims, and includes all modifications and variations within the meaning and scope equivalent to the scope of claims.

  The electricity storage device of the present invention is used not only for a power storage battery for power plants and homes as a backup power source, but also for a laminate type electricity storage device used as a power source battery for vehicles such as automobiles, motorcycles, trains and carts. Also applies.

As one embodiment of the present invention, a front view (A) showing the entire laminate type electricity storage device and a sectional view when the laminate type electricity storage device shown in (A) is viewed from the direction indicated by the line BB ( It is a perspective view (C) when the laminate type electrical storage device shown to B) and (A) is seen from the direction of a lead terminal. It is a figure which shows the state in each process of manufacture of the lamination type electrical storage device of this invention. The figure which shows a part of edge part of the lamination type electrical storage device before bending the bending part of a 1st laminate film, and the figure which shows a part of edge part of the lamination type electrical storage device after bending (B) It is. It is sectional drawing when the laminate type electrical storage device shown to (B) of FIG. 3 is seen from the direction of IV-IV line. It is sectional drawing which shows a part of cross section of the conventional lamination type electrical storage device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1: Laminated type electrical storage device, 100: Electrical storage element, 110: 1st laminated film, 111: Inner layer, 114: Bending part, 120: 2nd laminated film, 121: Inner layer, 123: Outer layer, 124: Notch.

Claims (1)

A storage element;
An outer packaging material made of a flexible film that houses the electricity storage element,
The outer packaging material includes a first outer packaging portion having a first inner surface layer facing the power storage element, a second inner surface layer facing the first inner surface layer with the power storage element interposed therebetween, and the second A second outer packet portion having an outer surface layer covering the outer surface of the inner surface layer of
In the electricity storage device in which the first inner surface layer and the second inner surface layer are fixed by being thermally welded around the electricity storage element, and the electricity storage element is sealed inside the outer packaging material.
A through-hole penetrating the second outer packet part is formed on the inner side of the edge of the second outer packet part,
The end portion of the first outer packet portion has a bent portion that is bent so as to cover the end portion of the second outer packet portion in which the through hole is formed,
In the bent part, the outer surface layer of the second outer packet part and the first inner surface layer of the first outer packet part are opposed to each other, and the first outer packet part is sandwiched by the second outer packet part. The electrical storage device with which the 1st inner surface layers oppose and are heat-welded through the said through-hole.

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