JP2013182677A - Laminate type power storage device - Google Patents

Abstract

Provided is a laminated electricity storage device capable of reliably joining a tab assembly portion and a lead and reducing damage to the exterior body even when a low-strength laminate film is used as the exterior body.
A pole group 15 in which a plurality of plate-like positive electrodes 11P and negative electrodes 11N are alternately stacked via separators 12, and a positive terminal 2P and a negative terminal connected to the plurality of positive electrodes 11P and negative electrodes 11N, respectively. , A laminate film that is an exterior body 1 that accommodates the electrode group 15, and an electrolyte, and the positive electrode terminal 2P and the negative electrode terminal are joined to the tab assembly 5P by leads 3P inside the exterior body 1, The portion joined to the lead 3P of the tab aggregate portion 5P is bent in the stacking direction of the pole group 15, and the lead 3P covers at least the surface of the tab aggregate portion 5P facing the pole group 15 and the tip thereof. Are joined together.
[Selection] Figure 2

Description

  The present invention relates to a laminated electricity storage device having a laminate film as an outer package.

  In recent years, secondary batteries are used not only as power sources for portable electronic devices such as mobile phones and notebook PCs, but also as storage batteries for electric vehicles, and various types and sizes are proposed according to their use. Has been. Various metal cases and laminate films have also been proposed for battery outer bodies.

  In particular, a laminated battery combining a flat electrode and a laminate film outer package can be easily designed for capacity by adjusting the number of laminated sheets, and a battery of any size and shape can be obtained by changing the area and shape even with the same capacity. It is attracting attention because of its high degree of freedom in shape and size, such as its ability to be manufactured.

  On the other hand, the laminate film exterior body has a drawback that it has a lower strength than a metal exterior body such as an aluminum alloy, and defects are easily generated by mechanical impact such as scratching or piercing. In particular, if protrusions or foreign matter exist inside the battery when pressure is applied from the outside, there is a concern that the laminate film may be damaged by these protrusions or foreign matter. Since such protrusions and foreign matters are easily formed at the joint between the electrode electrode and the tab of the electrode, and the electrode tab in the battery, in Patent Document 1, the tab assembly portion and the lead It has been proposed to prevent the formation of sharp protrusions on the end surface of the joint portion between the tab assembly portion and the lead by making the end surface of the joint portion have an arc shape.

JP 2004-241328 A

  However, in the structure described in Patent Document 1, when the tab joint portion and the lead joint portion are bent in the thickness direction of the pole group in which the positive electrode and the negative electrode are laminated, a force similar to that of T-type peeling is applied to the joint portion. There was a concern that the joint would peel off. In addition, when the number of stacked electrodes is small and the thickness of the joint between the tab assembly and the lead is thin, the joint becomes a thin blade, which comes into contact with the laminate film as the exterior body, and the laminate film exterior There was concern about damaging the body.

  The present invention has been devised in view of such a problem, and in the stacked power storage device, by making the joint portion of the tab assembly portion and the lead a specific structure, the tab assembly portion and the lead are reliably joined, It is an object of the present invention to provide a stacked electricity storage device that can reduce damage to an exterior body even when a low-strength laminate film is used as the exterior body.

The stacked electricity storage device of the present invention includes a group of electrodes in which a plurality of plate-like positive electrodes and negative electrodes are alternately stacked via separators, and a plurality of the positive electrodes and the negative electrodes respectively connected to the positive electrodes and the negative electrodes. A positive electrode tab in which the positive electrode terminal is assembled with positive electrode tabs provided on the positive electrode by a positive electrode lead inside the outer package body. The negative electrode terminal is bonded to a negative electrode tab aggregate portion in which negative electrode tabs provided on the negative electrode are aggregated by a negative electrode lead inside the exterior body, and the positive electrode tab aggregate portion is bonded to the aggregate portion. And a portion of the negative electrode tab assembly portion joined to the positive electrode lead and the negative electrode lead is bent in the stacking direction of the electrode group, and the positive electrode lead and the front Negative electrode lead, characterized in that it is joined to cover at least the opposite surface and the positive electrode tab set part and the electrode group of the negative electrode tab collecting part its distal end.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to join a tab assembly part and a lead reliably, even when a low intensity | strength laminated film is used as an exterior body, the lamination type electrical storage device which can reduce the failure | damage of an exterior body can be provided.

It is the perspective view which showed typically the lamination type electrical storage device which is one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line A-A ′ in the vicinity of a joint portion between the tab assembly portion and the lead in FIG. 1. It is sectional drawing of the junction part of a tab assembly part and lead | read | reed in another embodiment of this invention. It is sectional drawing of the junction part of a tab assembly part and a lead | read | reed in the conventional laminated | stacked electrical storage device.

  A stacked electricity storage device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The stacked electricity storage device of the present embodiment includes a pole group 15 in which a plurality of plate-like positive electrodes 11P and negative electrodes 11N are alternately stacked via separators 12 inside the outer package 1. The pole group 15 housed inside the exterior body 1 and the external circuit are electrically connected by the terminal electrode 2 exposed from the sealing portion of the exterior body 1.

  The outer package 1 is a flexible film that does not allow moisture or gas to pass, which is called a laminate film, and is generally formed by laminating a polyethylene terephthalate (PET) film, an aluminum foil, and a sealing resin layer in this order. Has been. As the laminate film used in the present embodiment, a general aluminum laminate film marketed for foods and batteries can be used, and further, considering the use of the final laminated power storage device, battery shape, and the like. Select the material.

  As the material of the terminal electrode 2, aluminum can be used for the positive electrode, and copper or nickel can be used for the negative electrode. As for the thickness and width of the terminal electrode 2, in either case of the positive electrode or the negative electrode, take into consideration the capacity of the power storage device, the current value used, etc. That's fine. In addition, when using the thick terminal electrode 2, in order to prevent the airtight defect by the adhesion failure with the exterior body 1 which consists of a terminal electrode 2 and a laminate film, the sealing resin layer of the laminate film which is the exterior body 1 is made thick. Alternatively, a sealing resin may be separately bonded to the terminal electrode 2 in advance.

The connection structure between the tab and the lead in this embodiment will be described with reference to FIG. 2 shows a configuration in which four pairs of the positive electrode 11P and the negative electrode 11N are stacked via the separator 12, the number of the positive electrode 11P and the negative electrode 11N may be 1 to 3, or 5 or more. I do not care. The electrode group 15 is formed by stacking the positive electrode 11P, the negative electrode 11N, and the separator 12 in this manner. The pole group 15 may include a positive electrode current collector 10P and a negative electrode current collector 10N. Further, the positive electrode current collector 10P and the positive electrode 11P may be collectively referred to as a positive electrode 11P, and the negative electrode current collector 10N and the negative electrode 11N may be referred to as a negative electrode 11N. A positive electrode 11P is disposed as an electrode located in the outermost layer portion of the stacked electrode group 15, and the positive electrode 11P is formed by forming the positive electrode 11P only on one main surface of the positive electrode current collector 10P. . Any electrode other than the positive electrode 11P located in the outermost layer portion of the pole group 15 is one in which the positive electrode 11P is formed on both main surfaces of the positive electrode current collector 10P or the negative electrode 11N on both main surfaces of the negative electrode current collector 10N. Is formed.

  And the pole group 15 contains electrolyte (not shown) in order to express the function as an electrical storage device.

  Each of the current collectors is provided with a tab for electrically connecting the leads of the terminal electrode 2. FIG. 2 shows the positive electrode tab 4P provided on the positive electrode current collector 10P. The plurality of positive electrode tabs 4P provided on the plurality of positive electrode current collectors 10P are bundled together in the positive electrode tab assembly portion 5P. One end of the positive electrode lead 3P is electrically connected to the positive electrode tab assembly portion 5P, and the other end of the positive electrode lead 3P is drawn out of the exterior body 1 through the sealing portion of the exterior body 1 and becomes a positive electrode terminal 2P. ing.

  FIG. 4 schematically shows an example of a cross section in the vicinity of the junction between the positive electrode tab assembly 5P and the positive electrode lead 3P of the conventional stacked type electricity storage device. In the conventional stacked-type electricity storage device, the positive electrode tab assembly portion 5P is bent in the stacking direction of the pole group 15, and the positive electrode lead 3P is on the opposite side of the surface of the bent positive electrode tab assembly portion 5P facing the electrode group 15. It is joined to the surface. Therefore, the joined positive electrode tab assembly portion 5P and the end portion of the positive electrode lead 3P are in direct contact with the exterior body 1 made of a laminate film in a sharp state that is cut to a desired length. .

  On the other hand, in the present embodiment, as shown in FIG. 2, the positive electrode tab assembly portion 5P is bent in the stacking direction of the pole group 15, and the positive electrode lead 3P is connected to the pole group 15 of the bent positive electrode tab assembly portion 5P. It is joined to the opposite surface so that one end of the positive electrode lead 3P is located at the bent portion of the positive electrode tab assembly portion 5P, and is further bent so as to cover the tip portion of the positive electrode tab assembly portion 5P facing the stacking direction of the pole group 15. ing. Thus, compared with the case where the positive electrode lead 3P and the positive electrode tab assembly portion 5P are joined so that the front end portions of the positive electrode lead 3P and the positive electrode tab assembly portion 5P coincide with each other by covering the front end portion of the positive electrode tab assembly portion 5P, The bonding strength can be increased, and the possibility that the exterior body 1 is damaged by the tip of the bonding portion can be reduced. In the present embodiment, the positive electrode lead 3P only needs to be bonded to the surface facing the pole group 15 of the bent positive electrode tab assembly portion 5P, but further, the stacking direction of the pole group 15 of the positive electrode tab assembly portion 5P. It is preferable that the front-end | tip part which faces is also joined.

  Further, as shown in FIG. 3, the positive electrode lead 3P is folded back so as to cover the front end portion of the positive electrode tab assembly portion 5P facing the stacking direction, and the surface opposite to the electrode group 15 of the positive electrode tab assembly portion 5P and the opposite side thereof. It is preferable to arrange so as to cover the surface. By thus folding back the positive electrode lead 3P, it is possible to more reliably prevent the front end portion of the positive electrode tab assembly portion 5P from coming into contact with the exterior body 1 made of a laminate film. At this time, the positive electrode lead 3P is preferably bonded to both the surface facing the electrode group 15 of the positive electrode tab assembly portion 5P and the surface on the opposite side thereof. Further, the folded portion of the positive electrode lead 3P does not necessarily have to be joined or in contact with the tip portion of the positive electrode tab assembly portion 5P.

The width of the positive electrode lead 3P is larger than the width of the positive electrode tab assembly portion 5P, so that the side end portion adjacent to the front end portion of the positive electrode tab assembly portion 5P facing the stacking direction of the electrode group 15 is also made of a laminate film. Contact with the outer package 1 can be prevented, which is preferable. Further, in addition to the entire positive electrode tab assembly portion 5P, that is, the surface facing the electrode group 15 of the positive electrode tab assembly portion 5P and the opposite surface thereof, the tip portion facing the stacking direction of the electrode group 15, the side adjacent to the tip portion It is preferable that the end portion is also disposed so as to cover the positive electrode lead 3P. In order to obtain such a structure, one end of the positive electrode lead 3P is formed in a bag shape that accommodates the positive electrode tab assembly portion 5P, or is formed in a cross shape so that the tip portion and the side of the positive electrode tab assembly portion 5P are formed at that portion. Folded to cover the end.

  Moreover, it is preferable that the peripheral part of the positive electrode lead 3P is chamfered. When the positive electrode lead 3P is processed by a cutting method such as pressing or shearing, burr and burr may be formed on the cut surface depending on the cutting method and conditions, and the sealing resin does not break through the laminate film. If the metal foil penetrates through the layers and occurs simultaneously on the positive electrode side and the negative electrode side, there is a possibility of short-circuiting and causing the risk of heat generation or ignition. By removing burr and burrs that may damage the laminate film, it is possible to more effectively prevent the occurrence of defects.

  The positive side tab and lead connection structure in the present embodiment has been described above, but this is not limited to the positive side, and the same structure can be applied to the negative side tab and lead connection structure.

  Although the aluminum foil is generally used for the positive electrode current collector 10P, a metal foil made of stainless steel or titanium can also be used. In the case of an aluminum foil, the thickness of the positive electrode current collector 10P is preferably in the range of 10 to 40 μm from the viewpoint of combining flexibility and strength. In the case of other metal foils, the metal foil may be appropriately selected from the viewpoint of flexibility and strength in the production process.

  Since the positive electrode tab 4P is generally formed integrally with the positive electrode current collector 10P, it has the same material and thickness as the positive electrode current collector 10P. The width of the positive electrode tab 4P is designed to be large enough not to cause a problem such as heat generation according to the capacity and use conditions of the power storage device, and not to cause a short circuit due to contact with the negative electrode tab 4N or the negative electrode lead 3N. That's fine.

  The same material as that of the positive electrode current collector 10P may be basically used for the positive electrode lead 3P whose one end is drawn out of the exterior body 1 and becomes the positive electrode terminal 2P. Specifically, aluminum is suitably used in terms of cost, flexibility, strength, etc., and titanium and stainless steel can also be used. The widths of the positive electrode lead 3P portion located inside the outer package 1 and the positive electrode terminal 2P portion located outside the outer package 1 may be basically the same, but may be changed as necessary. Further, the width of the positive electrode lead 3P is preferably wider than the width of the positive electrode tab assembly portion 5P, but the positive electrode lead 3P particularly has a tip of the positive electrode tab assembly portion 5P that causes damage to the outer package 1 made of a laminate film. Since the damage of the exterior body 1 made of a laminate film can be reduced by covering the portion, there is no particular limitation. Further, the thickness of the positive electrode lead 3P may be appropriately selected in consideration of the bonding with the positive electrode tab assembly portion 5P, the bending process at the tip portion, and the connection between the positive electrode terminal 2P and an external circuit. Although not limited, for example, about 0.1 mm is appropriate.

  On the other hand, a copper foil is generally used for the negative electrode current collector 10N, but a metal foil made of stainless steel or nickel can also be used. In particular, in an electricity storage device using an Li salt as an electrolyte, such as a lithium ion battery, it is preferable to use a metal foil that is not alloyed with lithium ions. In the case of copper foil, the thickness of the negative electrode current collector 10N is preferably in the range of 5 to 20 μm from the viewpoint of having both flexibility and strength. In the case of other metal foils, the metal foil may be appropriately selected from the viewpoint of flexibility and strength in the production process.

  Since the negative electrode tab 4N (not shown) is formed integrally with the negative electrode current collector 10N as in the case of the positive electrode tab 4P, it has the same material and thickness as the negative electrode current collector 10N. Similarly to the positive electrode tab 4P, the width of the negative electrode tab 4N is large enough not to cause problems such as heat generation according to the capacity of the power storage device and usage conditions, and short-circuited in contact with the positive electrode tab 4P and the positive electrode lead 3P. Design to the extent that does not occur.

  The same material as that of the negative electrode current collector 10N may be basically used for the negative electrode lead 3N (not shown) whose one end is drawn out of the exterior body 1 and becomes the negative electrode terminal 2N (not shown). Specific examples include copper, nickel, and stainless steel, but it is also possible to use a copper-coated nickel or a clad material bonded with a dissimilar metal. The width of the negative electrode lead 3N portion located inside the exterior body 1 and the width of the negative electrode terminal 2N portion located outside the exterior body 1 may be basically the same, but may be changed as necessary. Further, the width of the negative electrode lead 3N is preferably wider than the width of the negative electrode tab assembly portion 5N, but the negative electrode lead 3N particularly causes the tip of the negative electrode tab assembly portion 5N to cause damage to the outer package 1 made of a laminate film. Since the damage of the exterior body 1 made of a laminate film can be reduced by covering the portion, there is no particular limitation. Further, the thickness of the negative electrode lead 3N may be appropriately selected in consideration of the bonding with the negative electrode tab assembly portion 5N, the bending process at the tip portion, and the connection between the negative electrode terminal 2N and an external circuit. Although not limited, for example, about 0.1 mm is appropriate.

  Next, the configuration of the pole group 15 of the present embodiment will be described using a lithium ion battery as a representative example. The pole group 15 has a structure in which the positive electrode 11P formed on the positive electrode current collector 10P and the negative electrode 11N formed on the negative electrode current collector 10N are alternately stacked via the separator 12.

  As the active material used for the positive electrode 11P, a positive electrode active material applicable to a lithium ion battery may be used. Such positive electrode active materials include, for example, lithium cobalt composite oxide, lithium manganese composite oxide, lithium nickel composite oxide, lithium nickel cobalt composite oxide, lithium nickel cobalt manganese composite oxide, lithium nickel manganese composite oxide, Examples thereof include lithium vanadium composite oxide, manganese dioxide, and vanadium oxide. In particular, a lithium cobalt composite oxide and a lithium nickel manganese composite oxide are preferable because they have a high charge / discharge potential and a large charge / discharge capacity, so that a battery having a large energy density can be constructed when used as an active material.

  The positive electrode 11P is formed by directly applying a slurry in which a positive electrode active material, a conductive agent, a binder, and the like are dispersed in a solvent to a metal foil serving as the positive electrode current collector 10P, drying, and pressing as necessary. A method of forming a mixture in which a positive electrode active material is mixed with a conductive agent or a binder without using a solvent together with the positive electrode current collector 10P, and a sintered body mainly composed of the positive electrode active material Can be manufactured by a method of bonding the positive electrode current collector 10P to the positive electrode current collector 10P using a conductive adhesive, and the manufacturing method thereof is not particularly limited.

Hereinafter, as an example of the manufacturing method of the positive electrode 11P, a manufacturing method in the case where the sintered body mainly including lithium cobalt composite oxide (LiCoO ₂ ) as an active material is used as the positive electrode 11P will be described in detail.

Any of the following (1) to (3) may be used for the production of the sintered body.
(1) The active material is mixed with a molding aid, water or a solvent to which a dispersant and a plasticizer are added if necessary to prepare a slurry, and the slurry is applied to a substrate film, dried, and then dried. Peel from the film and sinter.
(2) A material obtained by directly or granulating an active material is put into a mold, pressed with a press machine, and then sintered.
(3) The granulated active material is pressure-formed with a roll press machine, processed into a sheet, and sintered.
The granulation of (2) and (3) may be either wet granulation or dry granulation from the slurry described in the method (1).

As a raw material powder of LiCoO ₂ which is a positive electrode active material, it is preferable to use a fine powder having a specific surface area of 1 m ² / g or more and a primary particle size of 3 μm or less. By using such a fine powder, densification at a relatively low temperature is possible, and a dense sintered body free from different phases can be obtained. Here, the dense sintered body refers to a sintered body having a porosity of 15% or less, and the firing temperature for obtaining such a sintered body depends on the sinterability of the raw material powder. What is necessary is just to select suitably in the range of 1000 degreeC.

  Examples of the molding aid include one or a mixture of two or more of polyacrylic acid, carboxymethyl cellulose, polyvinylidene fluoride, polyvinyl alcohol, diacetyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, butyral, and the like. Of these, a butyral binder is preferred as the binder. Since the butyral binder has high strength, the amount added can be reduced, and a high-density sintered body can be obtained. The amount of the binder is preferably 10% by volume or less with respect to the active material as the raw material powder.

  As a base film, resin films, such as a polyethylene terephthalate, a polypropylene, polyethylene, a tetrafluoroethylene, can be used, for example.

  The conductive adhesive for bonding the obtained sintered body of the positive electrode active material to the positive electrode current collector 10P includes conductive bonding using a carbon material, gold, silver, copper, platinum, gold coated particles, or the like as a filler. It is appropriate to use an agent. On the positive electrode side, a carbon-based conductive adhesive using a carbon material as a filler is particularly suitable so that the filler does not elute during charging. For example, 3315E manufactured by ThreeBond can be used.

On the other hand, examples of the active material used for the negative electrode 11N include negative electrode active materials applicable to lithium ion batteries, such as metal lithium, alloys capable of inserting and extracting lithium ions, carbon materials, metal materials, oxides, and lithium-containing composite oxides. Substances can be used. Examples of such negative electrode active materials include Si alloys and Sn alloys for alloys, graphite and hard carbon for carbon materials, Al, In, and Si for metal materials, and titanium oxide and tungsten oxide for oxides. , Molybdenum oxide, niobium oxide, vanadium oxide, iron oxide, and the like, and lithium composite oxides composed of these oxides and lithium. In particular, lithium titanate (Li ₂ Ti ₃ O ₇ and its related active materials) has a high charge / discharge potential in the vicinity of 1.5 V and the negative electrode active material, so that deposition of metallic lithium on the negative electrode surface during charge / discharge is performed. Therefore, a highly safe battery can be obtained, which is preferable.

  The negative electrode 11N can be manufactured by the same method as the positive electrode 11P. In particular, when an oxide or a lithium composite oxide is used as the negative electrode active material, a battery having a high energy density can be constructed by using it as a sintered body.

  As the separator 12, for example, a polyolefin fibrous nonwoven fabric, a microporous membrane made of polyolefin, or a ceramic porous material can be used. Here, examples of the polyolefin include polyethylene and polypropylene, and a separator generally used for a lithium ion battery is applicable.

As the electrolyte contained in the electrode group 15, any of organic electrolyte solution, polymer solid electrolyte, inorganic solid electrolyte, ionic liquid, and the like can be used. The organic electrolyte is composed of an organic solvent and an electrolyte salt, and an additive for the purpose of forming a film on the electrode surface, preventing overcharge, imparting flame retardancy, or the like may be added as necessary. As the organic solvent, those having a high dielectric constant, low viscosity and low vapor pressure are suitably used. Examples of such materials include ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfolane, Examples thereof include a solvent in which one or two or more selected from 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, methylethyl carbonate, dimethyl carbonate, and diethyl carbonate are mixed. Examples of the electrolyte salt include lithium salts such as LiClO ₄ , LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LiN (C ₂ F ₅ SO ₂ ) ₂ .

  Further, when a polymer solid electrolyte or an inorganic solid electrolyte is used as the electrolyte, these electrolytes may be disposed in place of the separator 12.

  Next, a method for forming the tab-lead connecting portion in this embodiment will be described.

  As shown in FIG. 2, a plurality of positive electrode tabs 4P provided on a plurality of positive electrode current collectors 10P are bundled together to form a positive electrode tab assembly portion 5P. At this time, the positive electrode tabs 4P may have different lengths as desired. When the formed positive electrode tab assembly portion 5P is bent in the stacking direction of the pole group 15, the tip of the positive electrode tab assembly portion 5P is the outermost part of the surface of the pole group 15 facing the tip portion (in FIG. It cuts and arranges at an appropriate position so as not to protrude from the positive electrode current collector 10P) located in the uppermost layer of the pole group 15.

  The surface facing the electrode group 15 when the electrode tab assembly 5P is bent in the stacking direction of the electrode group 15 (in FIG. 2, the electrode tab 4P connected to the electrode current collector 10P located at the uppermost layer of the electrode group 15) Further, one end of the positive electrode lead 3P is overlapped, and the positive electrode tab assembly portion 5P and the positive electrode lead 3P are bonded using a technique such as ultrasonic bonding or laser welding. At this time, it arrange | positions so that the end of the positive electrode lead 3P may be located in the bending part of the positive electrode tab assembly part 5P.

  Thereafter, the joint between the positive electrode tab assembly 5P and the positive electrode lead 3P is bent in the stacking direction of the pole group 15, and the positive electrode lead 3P may be bent so that the tip of the positive electrode tab assembly 5P is on the inside. At this time, the structure as shown in FIG. 2 can be formed by bending the positive electrode lead 3P along the laminated surface of the electrode group 15 in the vicinity of the tip of the positive electrode tab assembly 5P. In order to form the structure as shown in FIG. 3, it is further folded along the positive electrode tab assembly portion 5P, or after the positive electrode lead 3P is folded so as to sandwich the positive electrode tab assembly portion 5P, ultrasonic bonding or laser welding is performed. The positive electrode tab assembly 5P and the positive electrode lead 3P may be joined using a technique such as the above. The connecting portion between the negative electrode tab and the lead may be formed in the same manner.

  The pole group 15 in which the tab and lead connection portions are formed in this manner is sandwiched between the laminate films as the outer package 1, and the other end not connected to the lead tab is pulled out of the outer package 1 as the terminal electrode 2. Thus, a lithium ion battery can be formed by sealing the opening of the outer package 1. Sealing of the outer package 1 may be performed by adhering the sealing resin layers by sandwiching the pole group 15 with the sealing resin layer side of the laminate film as an inner side and thermocompression-bonding the opening. Moreover, when using electrolyte solution as electrolyte, after adhering except the part which inject | pours the electrolyte solution of a laminate film, after inject | pouring electrolyte solution from the part which has not adhere | attached, an opening part should just be thermocompression-bonded.

  As described above, the present embodiment has been described in detail by taking a lithium ion battery as an example, but the present invention is not limited to this, and a lead battery, a nickel cadmium battery, a nickel hydrogen battery, an electric double layer capacitor, a lithium ion The present invention can also be applied to various secondary batteries such as capacitors, capacitors, and other similar stacked electric storage devices.

DESCRIPTION OF SYMBOLS 1 ... Exterior body 2 ... Terminal electrode 2P ... Positive electrode terminal 3P ... Positive electrode lead 4P ... Positive electrode tab 5P ... Positive electrode tab assembly part 10P ... Positive electrode current collector 10N ... Negative electrode current collector 11P ·· Positive electrode 11N ·· Negative electrode 12 ... Separator 15 ... Pole group

Claims (5)

A group of poles in which a plurality of plate-like positive electrodes and negative electrodes are alternately laminated via separators;
A positive terminal and a negative terminal connected to a plurality of the positive and negative electrodes, respectively;
A laminate film that is an exterior body that houses the electrode group, and an electrolyte,
The positive electrode terminal is joined to a positive electrode tab assembly portion in which positive electrode tabs provided on the positive electrode are assembled by a positive electrode lead in the exterior body,
The negative electrode terminal is joined to a negative electrode tab assembly portion in which negative electrode tabs provided on the negative electrode are assembled by a negative electrode lead in the exterior body,
Portions joined to the positive electrode lead and the negative electrode lead of the positive electrode tab assembly portion and the negative electrode tab assembly portion are bent in the stacking direction of the electrode group, and the positive electrode lead and the negative electrode lead are at least the A laminated power storage device, wherein the positive electrode tab assembly portion and the negative electrode tab assembly portion are joined so as to cover a surface of the negative electrode tab assembly portion facing the electrode group and a tip portion thereof.   The positive electrode lead and the negative electrode lead are further disposed so as to cover surfaces of the positive electrode tab assembly portion and the negative electrode tab assembly portion opposite to the surface facing the electrode group, respectively. 2. The stacked electricity storage device according to 1.   3. The stacked electricity storage device according to claim 1, wherein widths of the positive electrode lead and the negative electrode lead are larger than widths of the positive electrode tab assembly portion and the negative electrode tab assembly portion, respectively.   4. The stacked electricity storage device according to claim 3, wherein the positive electrode lead and the negative electrode lead are disposed so as to further cover the positive electrode tab assembly portion and the entire negative electrode tab assembly portion, respectively.   The multilayer electrical storage device according to any one of claims 1 to 4, wherein peripheral edges of the positive electrode lead and the negative electrode lead are chamfered.

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