JP2010238481A - Laminate exterior power storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate exterior power storage device capable of obtaining sufficient air-tightness in a usual usage state and, in case of gas being generated inside an exterior body, exhausting the gas surely from a specific site. <P>SOLUTION: In the laminate exterior power storage device, an exterior body has exterior films laminated each other which are bonded air-tight at bonding parts formed on each of outer circumferential parts, a power storage device element and an electrolyte solution are housed in a housing part formed inside the exterior body, non-bonded sites are formed on each of the outer circumferential parts of the exterior films consisting of the exterior body communicating to the housing part, surrounded by the bonded part, an intermediate film is interposed between each of the non-bonded sites of the exterior films, at least parts of a surface and a rear surface of the intermediate film are adhered to each of the exterior films, and holes penetrating the exterior films are formed in at least either of regions where the intermediate film is adhered in at least one of the exterior films. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminate-cased electricity storage device, and more particularly to a laminate-cased electricity storage device in which an electricity storage device element such as a battery or a capacitor (capacitor) is accommodated by an exterior body made of two exterior films.

  In recent years, an electricity storage device element such as a battery element in which a positive electrode plate and a negative electrode plate are wound or alternately laminated via a separator is accommodated in an outer package made of two outer films together with an electrolytic solution. Laminate exterior power storage devices (batteries and capacitors) are used as power sources for portable devices and electric vehicles.

  In such a laminated exterior electricity storage device, a gas such as a flammable gas is generated inside the exterior body due to electrolysis or thermal decomposition of the electrolytic solution by being overcharged or exposed to a high temperature. This may cause an increase in the internal pressure of the exterior body. Thus, in order to solve such a problem, a portion having a weak bonding force (hereinafter also referred to as “weakly bonded portion”) is formed in a part of the bonded portion of the two exterior films in the exterior body, When the gas pressure rises, a safety mechanism that makes this weak joint function as a safety valve for degassing, or automatically opens when the internal pressure rises above a predetermined value, such as flammable gas A laminated exterior power storage device provided with a safety mechanism having a safety valve that exhausts the air to the outside has been proposed (see, for example, Patent Document 1 to Patent Document 5).

FIG. 15 shows an exploded configuration of an example of a laminated exterior power storage device provided with a safety mechanism in which a weakly joined portion is formed at a joined site in an exterior body. The laminate body of the laminated exterior power storage device 50 is such that the outer periphery portion is heat-sealed over the entire periphery in a state where the upper exterior film 51A and the lower exterior film 51B are overlapped to form the joint portion 52. Thus, a housing portion for housing the electricity storage device element is formed therein, and a thin electricity storage device element (for example, a battery element or a capacitor element) 55 is housed together with the organic electrolyte in the housing portion of the exterior body. Has been.
The laminated exterior power storage device 50 is provided with a weak joint portion 53 in a part of the joint portion 52, and even when a large amount of gas is generated in the exterior body by the weak joint portion 53 acting as a safety valve. The outer body is prevented from rupturing by releasing the pressure from the weakly bonded portion 53 and releasing the pressure. Specifically, the weak joint portion 53 has a lower seal strength than the other portions in the joint portion 52, and the internal pressure of the housing portion in which the power storage device element (battery element or capacitor element) is housed in the exterior body is reduced. When the predetermined value is reached, the weakly bonded portion 53 is preferentially separated to form an exhaust port.
Moreover, in the example of this figure, the exterior body has a rectangular outline shape, and a plurality of positive electrode plates constituting an electric storage device element (battery element or capacitor element) 55 from each of the two short sides. A positive electrode power tab 56 which is a common positive electrode lead member electrically connected to each of the plurality of negative electrode plates, and a negative electrode power supply tab 57 which is a common negative electrode lead member electrically connected to each of the plurality of negative electrode plates are pulled out. It is.

  In the laminated exterior electricity storage device having such a configuration, the weakly bonded portion constituting the safety mechanism is surely peeled when the internal pressure of the accommodating space reaches a predetermined value, and an exhaust port is formed, and In a normal use state, a sealing strength that is surely sealed and ensures sufficient reliability is required. However, it is not easy to reliably form a weakly bonded portion having such a sealing strength from the viewpoint of manufacturing.

In addition, as a safety mechanism of the laminated exterior power storage device, a non-conducting structure that is continuous with the storage portion in which the power storage device element is stored and has a cove shape with respect to the storage portion is provided in at least one of the regions where the joint portion is formed. A stress concentration part where the peeling stress that occurs in the part where the exterior film is fused is formed in the joint part region, and the pressure release part that connects the inside and the outside by peeling the exterior film in this stress concentration part Has been proposed (see Patent Document 6).
However, in such a safety mechanism, the stress concentration portion is formed by heat-sealing the exterior films made of the same quality materials, and in order to cause the stress concentration portion to peel at a relatively low pressure. However, since it is necessary to considerably reduce the fusion width in the pressure concentration portion, there is a problem that it is difficult to ensure sufficient airtightness in a normal use state.

Japanese Patent No. 3554155 Japanese Patent Laid-Open No. 05-013061 Japanese Patent Laid-Open No. 11-086823 JP 2006-236605 A JP 2007-157678 A Japanese Patent No. 3895645

  The present invention has been made on the basis of the above circumstances, and its purpose is that when sufficient airtightness is obtained in a normal use state, and gas is generated inside the exterior body of the laminated exterior electricity storage device. An object of the present invention is to provide a laminated exterior electricity storage device that can reliably discharge the gas from a specific part.

The laminated exterior power storage device of the present invention has an exterior body in which exterior films stacked on each other are airtightly joined to each other at joints formed on the respective outer peripheral edges, and formed inside the exterior body. A laminated exterior electricity storage device configured to contain an electricity storage device element and an electrolyte in the accommodation portion,
In each outer peripheral edge portion of the exterior film constituting the exterior body, a non-joined portion that is surrounded by the joint portion and communicates with the housing portion is formed,
An intermediate film is interposed between each non-bonded portion of the exterior film, and at least a part of the front and back surfaces of the intermediate film is bonded to each of the exterior films, and at least one exterior film In the region where the intermediate film is bonded, a hole portion penetrating the exterior film is formed.

In the laminated exterior electricity storage device of this invention, it is preferable that the hole part which penetrates the said exterior film is formed in the area | region where the said intermediate | middle film in both exterior films was adhere | attached.
In such a laminated exterior power storage device, when seen through in the thickness direction of the exterior film, the area where the intermediate film is adhered in one exterior film, and the area where the intermediate film is adhered in the other exterior film, However, it may be formed so that at least a part thereof overlaps each other.
Further, when viewed in the thickness direction of the exterior film, the hole portion in one of the exterior films and the hole portion in the other exterior film may be formed so that at least a part thereof overlaps.
Moreover, in the laminated exterior electrical storage device of this invention, it is preferable that the said intermediate | middle film is adhere | attached on the exterior film by heat sealing | fusion.
Moreover, it is preferable that the said intermediate | middle film consists of a metal film, a resin film, or the metal film by which the surface was coat | covered with resin.
Moreover, in the laminated exterior electrical storage device of this invention, the hole part of an exterior film is opened when the said intermediate | middle film peels from an exterior film with the raise of the internal pressure of an exterior body.

In the laminated exterior power storage device of the present invention, the gas generated in the housing portion in which the electrical storage device element in the exterior body is housed enters the non-joined portion formed on the outer peripheral edge, thereby the non-joined portion. Therefore, stress is applied to the intermediate film interposed between the non-bonded portions so as to peel the intermediate film from the exterior film. Further, since the intermediate film is peeled off from the exterior film by further expanding the non-bonded portion, the hole opening formed in the area where the intermediate film is bonded to the exterior film is opened. As a result, the hole opening The gas in the exterior body is discharged from the outside.
Thus, according to the laminated exterior electricity storage device of the present invention, the hole portion formed in the non-joined portion of the exterior film is closed by the intermediate film, and therefore has sufficient airtightness in a normal use state. In addition, the intermediate film can be made of a material different from that of the exterior film, and such an intermediate film is more easily peeled off than the joint portion where the exterior films are joined together. When a gas is generated in the case where the inside expands with the generation of the gas, the intermediate film peels preferentially over the bonded portion even at a relatively low internal pressure. Can be discharged reliably.

It is an explanatory top view which shows the structure of an example of the laminate-clad electricity storage device of this invention. It is explanatory drawing which shows the safety mechanism in the laminated exterior electrical storage device of FIG. It is sectional drawing for description which shows the principal part in the safety mechanism shown in FIG. It is explanatory drawing which shows the structure of an example of an electrical storage device element. In the safety mechanism shown in FIG. 3, it is sectional drawing for description which shows the state which the non-joining site | part expanded by the raise of internal pressure. In the safety mechanism shown in FIG. 3, it is sectional drawing for description which shows the state which the intermediate film peeled by expansion | swelling of the non-joining site | part. It is a top view for description which shows the structure of the other example of the lamination | stacking exterior electrical storage device of this invention. It is sectional drawing for description of the safety mechanism shown in FIG. In the safety mechanism shown in FIG. 8, it is explanatory sectional drawing which shows the state which the non-joining site | part expanded by the raise of internal pressure. In the safety mechanism shown in FIG. 8, it is sectional drawing for description which shows the state which the intermediate film peeled by expansion | swelling of the non-joining site | part. It is a top view for description which shows the structure of the further another example of the lamination | stacking exterior electrical storage device of this invention. It is sectional drawing for description of the safety mechanism shown in FIG. In the safety mechanism shown in FIG. 12, it is sectional drawing for description which shows the state which the non-joining site | part expanded by the raise of internal pressure. In the safety mechanism shown in FIG. 12, it is sectional drawing for description which shows the state which the intermediate | middle film peeled by expansion | swelling of the non-joining site | part. It is an exploded view for explanation showing the configuration of an example of a laminated exterior power storage device provided with a conventional safety mechanism.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a plan view for explaining the structure of an example of a laminated exterior power storage device of the present invention, FIG. 2 is an explanatory view showing a safety mechanism in the laminated exterior electrical storage device of FIG. 1, and FIG. It is sectional drawing for description which shows the principal part in the safety mechanism shown.
In this laminated exterior power storage device 10, the exterior body 20 has a rectangular upper exterior film 21 </ b> A and a lower exterior film 21 </ b> B each having heat-bonding properties, and is overlapped with each other over the entire circumference of each outer peripheral edge portion. The formed joint 22 is hermetically joined to each other. A housing part 23 for housing the electricity storage device element is formed inside the exterior body 20, and the electricity storage device element is housed together with the organic electrolyte in the housing part 23.
In the example shown in the drawing, the portion of the upper exterior film 21 </ b> A that forms the accommodating portion 23 is drawn.

The outer peripheral edge portions of the upper exterior film 21A and the lower exterior film 21B in the exterior body 20 have one side communicating with the housing portion 23 and the other side surrounded by the joint portion 22. The intermediate film 27 is interposed between the non-bonded portions 24 in each of the upper exterior film 21A and the lower exterior film 21B, and a part of each of the front and back surfaces of the intermediate film 27 is an adhesive portion. It is adhered to each of the upper exterior film 21A and the lower exterior film 21B by 26A and 26B. In the illustrated example, the adhesive portions 26A and 26B are disposed so as not to overlap each other when the upper exterior film 21A and the lower exterior film 21B are seen through in the thickness direction.
Then, in the non-bonded portion 24 in the upper exterior film 21A, a circular hole portion 25A penetrating the upper exterior film 21A is formed in a region where the intermediate film 27 is adhered, that is, a region where the adhesion portion 26A is formed. Thus, the hole portion 25A is closed by the intermediate film 27 so that the electrolyte does not leak. On the other hand, in the non-bonded portion 24 in the lower exterior film 21B, a circular hole 25B penetrating the lower exterior film 21B is formed in an area where the intermediate film 27 is adhered, that is, an area where the adhesive portion 26B is formed. As a result, the hole 25B is closed by the intermediate film 27 so that the electrolyte does not leak. In the illustrated example, the hole portions 25A and 25B in the non-bonded portions 24 of the upper exterior film 21A and the lower exterior film 21B do not overlap each other when the upper exterior film 21A and the lower exterior film 21B are seen through in the thickness direction. It is formed as follows.

As the upper exterior film 21A and the lower exterior film 21B constituting the exterior body 20, for example, a film in which a polypropylene (hereinafter referred to as “PP”) layer, an aluminum layer, a nylon layer, and the like are laminated in this order from the inside is suitable. Can be used.
When using, for example, a laminate of a PP layer, an aluminum layer and a nylon layer as the upper exterior film 21A and the lower exterior film 21B, the thickness is usually 50 to 300 μm.

The vertical and horizontal dimensions of the upper exterior film 21 </ b> A and the lower exterior film 21 </ b> B are appropriately selected according to the dimensions of the electricity storage device element 11 accommodated in the accommodating portion 23, but the longitudinal dimension is, for example, 40 to 200 mm, The dimension is 60 to 300 mm.
Moreover, the junction width of the junction part 22 of 21 A of upper exterior films and the lower exterior film 21B is 2-15 mm, for example.
Moreover, as a dimension of the non-joining site | part 24, although it is based also on the dimension of the junction part 22 and the accommodating part 23, the dimension of the one side connected to the accommodating part 23 is 5-40 mm, and the other side perpendicular | vertical to this one side (FIG. 1). The dimension of the side in the vertical direction is, for example, 3 to 12 mm.
Moreover, it is preferable that the diameter of hole part 25A, 25B is 0.5-8 mm, More preferably, it is 1.0-6.0 mm.

The intermediate film 27 may be rigid or flexible, but as the intermediate film 27, a metal film, a resin film, or a metal film whose surface is coated with a resin is used. It is preferable.
Specific examples of the metal film include aluminum, copper, and stainless steel.
Specific examples of the resin film include polypropylene, nylon, polyethylene and the like, but it is preferable to use a material different from the upper exterior film 21A and the lower exterior film 21B.

Although the dimension of the intermediate film 27 depends on the dimension of the non-bonded portion 24 and the diameters of the hole openings 25A and 25B, for example, the vertical and horizontal dimensions are preferably 5 to 38 mm in the horizontal direction. The side dimension is 3 to 10 mm.
Moreover, although the thickness of the intermediate film 27 is based also on the material of the said intermediate film 27, Preferably it is 0.1-1 mm, for example.
In addition, the region where the intermediate film 27 is bonded to the upper exterior film 21A and the lower exterior film 21B, that is, the dimensions of the adhesive portions 26A and 26B are the same as the dimensions of the non-joined portion 24 and the diameters of the hole portions 25A and 25B. However, in the case of a circle, the diameter is preferably 1 to 12 mm, more preferably 2 to 10 mm, and in the case of a rectangle, the size of one side is appropriately selected within a range of 1 to 12 mm. it can. Further, the shapes of the adhesive portions 26A and 26B are not limited to circular and rectangular, but may be rhombuses or other shapes.

Further, when the intermediate film 27 is adhered to the upper exterior film 21A and the lower exterior film 21B, it can be adhered using an appropriate adhesive so as to close the hole portions 25A, 25B. The hole portions 25A and 25B can be bonded together by heat-sealing the upper exterior film 21A and the lower exterior film 21B.
Moreover, if the intermediate film 27 is adhered in a state of being in close contact with the outer peripheral edge portions of the hole portions 25A and 25B in the upper exterior film 21A and the lower exterior film 21B so that the electrolyte does not leak, the intermediate film It is not necessary that the entire surface of 27 is adhered to the upper exterior film 21A and the lower exterior film 21B. For example, even if the entire surface 27 is adhered along the outer peripheral edge of the intermediate film 27, the upper exterior film 21A and the lower exterior film 21B May be adhered along the outer peripheral edge portions of the hole openings 25A and 25B.

As shown in FIG. 4, the power storage device element 11 constituting the laminate-clad power storage device 10 includes a plurality of positive electrode plates each having a positive electrode layer 12 formed on a positive electrode current collector 12 a via a separator S, respectively. A negative electrode current collector 13a has an electrode laminate 11a formed by alternately laminating a plurality of negative electrode plates each having a negative electrode layer 13 formed thereon. On the upper surface of the electrode laminate 11a, lithium ion ions are formed. A lithium metal (lithium electrode layer) 18 as a supply source is disposed, and a lithium electrode current collector 18 a is laminated on the lithium metal 18. Reference numeral 19 denotes a lithium electrode extraction member.
Each of the plurality of positive electrode plates is electrically connected to a common positive electrode lead member, for example, aluminum positive electrode power supply tab 14 via a take-out member 16. On the other hand, each of the plurality of negative electrode plates is electrically connected to a common negative electrode lead member 15, for example, a copper negative electrode power supply tab 15 via a take-out member 17.
Each of the positive electrode power supply tab 14 and the negative electrode power supply tab 15 is drawn out from one end and the other end of the exterior body 20 so as to protrude to the outside.

As the positive electrode layer 12 constituting the electricity storage device element 11, an electrode material formed by adding a conductive material (for example, activated carbon, carbon black, etc.) and a binder as necessary is used. As an electrode material constituting the positive electrode layer 12, lithium reversibly carrying possible, but are not limited to, for _{example, LiCoO 2, LiNiO 2, LiFeO} 2 or the like of the general formula: Li _x M _y O _z (where , M represents a metal atom, and x, y, and z are integers.) And a positive electrode active material such as a metal oxide, activated carbon, and the like.
Moreover, as the negative electrode layer 13 which comprises the electrical storage device element 11, what shape | molded the electrode material with the binder is used. The electrode material of the negative electrode layer 13 is not particularly limited as long as it can reversibly carry lithium. For example, powder, granular materials such as graphite, various carbon materials, polyacene-based substances, tin oxide, and silicon acid compounds, and granular form And negative electrode active materials.

Further, as the electrolytic solution, it is preferable to use an electrolyte in which an electrolyte is dissolved in an appropriate organic solvent. Specific examples of the organic solvent include aprotic organic solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, acetonitrile, and dimethoxyethane. These may be used alone or in combination of two or more. it can. As the electrolyte, which can produce lithium ion is used, and specific examples _{thereof, LiI, LiCIO 4, LiAsF 4} , LiBF 4, etc. LiPF ₆ and the like.

Such a laminated exterior electricity storage device 10 can be manufactured as follows, for example.
The upper exterior film 21A and the lower exterior film 21B in which the hole portions 25A and 25B are formed in the portions to be the non-bonded portions 24 are prepared, and the electricity storage device element 11 is provided at the position to be the accommodating portion 23 on the lower exterior film 21B. On the other hand, a heat block is disposed in a portion that becomes the non-joining portion 24 excluding a region where the adhesive portion 26B is formed, and an intermediate film 27 is disposed so as to close the hole portion 25B. A heat block is disposed in a portion other than the portion where the adhesive portion 26A is formed. Then, the upper exterior film 21A is overlaid on the electricity storage device element 11, and in this state, the three sides at the outer peripheral edges of the upper exterior film 21A and the lower exterior film 21B are heat-sealed. As a result, joint portions 22 are formed on three sides of the outer peripheral edge of the upper exterior film 21A and the lower exterior film 21B, and a non-joined portion 24 is formed on one side thereof, and further, the upper exterior film 21A and the lower exterior film are formed. Each non-bonded portion 24 of the film 21B is heat-sealed to a part of the front and back surfaces of the intermediate film 27, whereby an adhesive portion 27 is formed at the outer peripheral edge portion of the hole portions 25A and 25B, and the hole portion 25A. 25B are airtightly closed by the intermediate film 27.
And after removing a heat block, electrolyte solution is inject | poured between 21 A of upper exterior films, and the lower exterior film 21B, and also 1 side of the unfused in the outer periphery part of 21 A of upper exterior films and the lower exterior film 21B is carried out. By heat-sealing, the exterior body 20 is formed, and thus the laminated exterior power storage device 10 is obtained.

In the laminated exterior power storage device 10, the gas generated in the housing portion 23 that houses the electrical storage device element 11 in the exterior body 20 is formed on the outer peripheral edge portions of the upper exterior film 21 </ b> A and the lower exterior film 21 </ b> B. Since the non-joining part 24 enters and thereby the non-joining part 24 expands, the intermediate film 27 interposed between the non-joining parts 24 has the intermediate film as shown in FIG. Stress is applied to peel 27 from the upper exterior film 21A and the lower exterior film 21B. Further, when the non-bonded portion 24 is further expanded, as shown in FIG. 6, the intermediate film 27 is peeled off from the upper exterior film 21A or the lower exterior film 21B, and therefore the intermediate film in the upper exterior film 21A or the lower exterior film 21B. The hole portions 25A and 25B formed in the region where the 27 is bonded are opened, and as a result, the gas in the exterior body 20 is discharged to the outside from the hole portions 25A and 25B. At this time, the hole openings 25A and 25B may be opened entirely or partially.
Thus, according to such a laminated exterior power storage device, the hole portions 25A and 25B formed in the non-joined portions of the upper exterior film 21A and the lower exterior film 21B are blocked by the intermediate film 27. In addition, sufficient airtightness can be obtained in a normal use state, and the intermediate film 27 can be made of a material different from that of the upper exterior film 21A and the lower exterior film 21B. Since the exterior film 21A and the lower exterior film 21B are more easily peeled than the joined portion 22 joined together, when gas is generated inside the exterior body 20, when the inside expands as the gas is generated, a comparison is made. Even if the internal pressure is low, the intermediate film 27 peels preferentially over the joint 22, so Gas can be reliably discharged Anaguchi section 25A, from 25B to the outside.

  The laminated exterior electricity storage device of the present invention having such a configuration can be applied to an organic electrolyte battery as well as an organic electrolyte capacitor such as a lithium ion capacitor, but the organic electrolyte capacitor is an organic electrolyte. Since the charging capacity is small compared to the battery but it can be charged and discharged instantly, there is a possibility that the gas pressure change will increase. It is effective in the case.

As mentioned above, although embodiment was described about the laminate-clad electricity storage device of this invention, this invention is not limited to said embodiment, A various change can be added.
For example, as shown in FIGS. 7 and 8, when seen through in the thickness direction of the upper exterior film 21A and the lower exterior film 21B, the adhesive portion 26A (the upper exterior film 21A and the intermediate film 27 formed on the upper exterior film 21A). And an adhesive portion 26B (an adhesive region between the lower exterior film 21B and the intermediate film 27) formed on the lower exterior film 21B may be disposed so that at least a part thereof overlaps each other.
In such a laminated exterior electricity storage device, the gas generated in the accommodating portion 23 that accommodates the electricity storage device 11 in the exterior body 20 is formed on the outer peripheral edge portions of the upper exterior film 21A and the lower exterior film 21B. Since the non-joining part 24 enters into the non-joining part 24 and thereby the non-joining part 24 expands, the intermediate film 27 interposed between each non-joining part 24 has the intermediate film as shown in FIG. Stress is applied to peel 27 from the upper exterior film 21A and the lower exterior film 21B. Further, when the non-bonded portion 24 is further expanded, as shown in FIG. 10, the intermediate film 27 is peeled off from the upper exterior film 21A or the lower exterior film 21B, so that the intermediate film in the upper exterior film 21A or the lower exterior film 21B. The hole portions 25A and 25B formed in the region where the 27 is bonded are opened, and as a result, the gas in the exterior body 20 is discharged to the outside from the hole portions 25A and 25B. At this time, the hole openings 25A and 25B may be opened entirely or partially.

  Thus, according to such a laminated exterior power storage device, the hole portions 25A and 25B formed in the non-joined portions of the upper exterior film 21A and the lower exterior film 21B are blocked by the intermediate film 27. In addition, sufficient airtightness can be obtained in a normal use state, and the intermediate film 27 can be made of a material different from that of the upper exterior film 21A and the lower exterior film 21B. It is easier to peel off than the joint portion 22 where the exterior film 21A and the lower exterior film 21B are joined, and when the transparent portions 21A and 26B are seen through in the thickness direction of the upper exterior film 21A and the lower exterior film 21B, at least the adhesive portions 26A and 26B Since the portions are formed so as to overlap each other, the non-bonded portion 24 Even if it is slightly expanded, a large stress is applied between the upper exterior film 21A and the lower exterior film 21B and the intermediate film 27, and the both are more easily separated, so that when gas is generated inside the exterior body 20, When the inside expands with the generation of the gas, the intermediate film 27 peels preferentially over the joining portion 22 even with a relatively low internal pressure, so that the gas is surely released to the outside from the hole portions 25A and 25B. Can be discharged.

Further, as shown in FIGS. 11 and 12, when viewed through the thickness direction of the upper exterior film 21A and the lower exterior film 21B, the hole portion 25A in the upper exterior film 21A and the hole portion 25B in the lower exterior film 21B. May be formed so that at least a part thereof overlaps each other.
In such a laminated exterior electricity storage device, the gas generated in the accommodating portion 23 that accommodates the electricity storage device 11 in the exterior body 20 is formed on the outer peripheral edge portions of the upper exterior film 21A and the lower exterior film 21B. Since the non-joining part 24 enters and thereby the non-joining part 24 expands, the intermediate film 27 interposed between the non-joining parts 24 has the intermediate film 27 as shown in FIG. Stress is applied to peel 27 from the upper exterior film 21A and the lower exterior film 21B. Further, when the non-bonded portion 24 is further expanded, as shown in FIG. 14, the intermediate film 27 is peeled off from the upper exterior film 21A or the lower exterior film 21B, and therefore the intermediate film in the upper exterior film 21A or the lower exterior film 21B. The hole portions 25A and 25B formed in the region where the 27 is bonded are opened, and as a result, the gas in the exterior body 20 is discharged to the outside from the hole portions 25A and 25B. At this time, the hole openings 25A and 25B may be opened entirely or partially.

  Thus, according to such a laminated exterior power storage device, the hole portions 25A and 25B formed in the non-joined portions of the upper exterior film 21A and the lower exterior film 21B are blocked by the intermediate film 27. In addition, sufficient airtightness can be obtained in a normal use state, and the intermediate film 27 can be made of a material different from that of the upper exterior film 21A and the lower exterior film 21B. It is easier to peel off than the joint portion 22 where the exterior film 21A and the lower exterior film 21B are joined, and when viewed through the thickness direction of the upper exterior film 21A and the lower exterior film 21B, the hole portions 25A and 25B are Since at least a part is formed so as to overlap each other, Even when it is expanded, a large stress is applied between the upper exterior film 21A and the lower exterior film 21B and the intermediate film 27 so that they are more easily separated, so that when gas is generated inside the exterior body 20, When the inside expands with the generation of the gas, the intermediate film 27 peels preferentially over the joining portion 22 even with a relatively low internal pressure, so that the gas is surely released to the outside from the hole portions 25A and 25B. Can be discharged.

  Thus, the internal pressure value at which the intermediate film 27 peels can be adjusted by changing the formation positions of the adhesive portions 26A and 26B and the formation positions of the hole openings 25A and 25B.

Moreover, the hole part may be formed only in any one of an upper exterior film and a lower exterior film.
Moreover, the outline shape of the hole part of an upper exterior film and a lower exterior film is not restricted circularly, It can be set as a polygon, an ellipse, and other appropriate shapes.
Further, the planar shape of the adhesive portions 26A and 26B is not limited to a rectangle, and may be other polygons, circles, ellipses, or other appropriate shapes.

DESCRIPTION OF SYMBOLS 10 Laminated exterior electrical storage device 11 Electrical storage device element 11a Electrode laminated body 12 Positive electrode layer 12a Positive electrode collector 13 Negative electrode layer 13a Negative electrode collector 14 Positive electrode power supply tab 15 Negative electrode power supply tabs 16 and 17 Extraction member 18 Lithium metal (lithium electrode) layer)
18a Lithium electrode current collector 19 Lithium electrode take-out member 20 Exterior body 21A Upper exterior film 21B Lower exterior film 22 Joint part 23 Housing part 24 Non-joint part 25A, 25B Hole part 26A, 26B Adhesion part 27 Intermediate film 50 Laminate exterior electricity storage Device 51A Upper exterior film 51B Lower exterior film 52 Joint part 53 Weak joint part 55 Power storage device element 56 Positive electrode power tab 57 Negative electrode power tab S Separator

Claims (7)

The exterior films stacked on each other have exterior bodies that are airtightly joined to each other at the joints formed on the respective outer peripheral edges, and the storage device element and the storage device formed in the interior of the exterior body A laminated exterior electricity storage device configured to contain an electrolyte solution,
In each outer peripheral edge portion of the exterior film constituting the exterior body, a non-joined portion that is surrounded by the joint portion and communicates with the housing portion is formed,
An intermediate film is interposed between each non-bonded portion of the exterior film, and at least a part of the front and back surfaces of the intermediate film is bonded to each of the exterior films, and at least one exterior film A laminated exterior electricity storage device, wherein a hole portion penetrating the exterior film is formed in a region where the intermediate film is bonded.   When seen through in the thickness direction of the exterior film, a region where the intermediate film is adhered to one exterior film and a region where the intermediate film is adhered to the other exterior film are formed so that at least a part thereof overlaps The laminated exterior electricity storage device according to claim 1, wherein   The laminated exterior electricity storage device according to claim 1, wherein a hole opening that penetrates the exterior film is formed in a region where the intermediate film is bonded to both exterior films.   The hole part in one exterior film and the hole part in the other exterior film are formed so that at least a part overlaps each other when seen through in the thickness direction of the exterior film. The laminated exterior electrical storage device of Claim 2 or Claim 3.   The laminated outer energy storage device according to any one of claims 1 to 4, wherein the intermediate film is bonded to the outer film by heat fusion.   6. The laminated exterior electricity storage device according to claim 1, wherein the intermediate film is made of a metal film, a resin film, or a metal film whose surface is covered with a resin.   The laminated exterior according to any one of claims 1 to 6, wherein a hole portion of the exterior film is opened by peeling the intermediate film from the exterior film as the internal pressure of the exterior body increases. Power storage device.

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