WO2020066520A1 - Power storage element and power storage element production method - Google Patents

Abstract

This power storage element 1 is provided with an electrode body 5 and an exterior body 30. The electrode body 5 has a first electrode 10 and a second electrode 20 laminated in a first direction d1. The exterior body 30 defines a housing section 35 for housing the electrode body 5. The exterior body 30 includes a one-side region 30a located on one side in a second direction d2 not parallel to the first direction d1. The exterior body 30 has: a first exterior material 40 including a first bulged section 45 defining the housing section 35; and a second exterior material 50 joined to the first exterior material 40 in the one-side region 30a and forming a joint section 60. The joint section 60 has multiple bent parts 70 in the one-side region 30a. In the one-side region 30a, the tip part 61 of the joint section 60 is positioned so as to overlap with the housing section 35 in the first direction d1 at a position in the second direction d2 between the housing section 35 and the part of the joint section located furthest to the one side in the second direction d2.

Description

Electric storage element, method for manufacturing electric storage element

<< The present invention relates to a power storage device and a method for manufacturing the power storage device.

(4) As an example of a power storage element, a stacked battery in which a positive electrode and a negative electrode are alternately stacked is widely used, as proposed in, for example, JP2000-156208. As an example of the stacked battery, a lithium ion secondary battery is exemplified. One of the features of the lithium ion secondary battery is that it has a larger capacity than other types of stacked batteries. Lithium ion secondary batteries having such characteristics are expected to be widely used in various applications such as in-vehicle applications and stationary housing applications.

Such a power storage element is used by enclosing an electrode body having a plurality of electrodes in an exterior body. The exterior body is produced, for example, by joining the peripheral portions of two film-shaped exterior members. The electrode body is housed in a housing surrounded by a joint where the two exterior materials are joined.

By the way, in order to increase the strength of the joint of the exterior material and to secure the airtightness of the housing portion, it is required to increase the width of the joint of the exterior material in the electric storage element. On the other hand, it is required to increase the amount of power that can be supplied by the power storage element per volume occupied by the power storage element, that is, the so-called volume energy density. Since the electrode body cannot be accommodated in the joint of the exterior material, if the joint of the exterior material is widened, the volume energy density decreases. That is, it has been difficult to achieve both a wide joint portion of the exterior material and a high volume energy density.

The present invention has been made in consideration of such a point, and an object of the present invention is to increase a volume energy density of a power storage element while widening a joint of an exterior material.

The electricity storage element of the present invention,
An electrode body having a first electrode and a second electrode stacked in a first direction;
An outer body forming a housing part for housing the electrode body,
The exterior body includes a one-side region on one side in a second direction that is not parallel to the first direction,
The exterior body includes: a first exterior material including a first bulging portion forming the housing portion; and a second exterior material joined to the first exterior material in the one side region to form a joint. Have
The joint has a plurality of bent portions in the one side region,
The distal end of the joint in the one side region is positioned so as to overlap with the accommodation portion in the first direction, and is the one side in the second direction of the accommodation portion and the joint in the second direction. Located between the parts.

In the power storage device of the present invention, the bent portion in the one side region is a bent portion closest to a base end portion of the joint portion, and a first bent portion that bends the joint portion to one side in the first direction. And a second bent portion that bends the joint portion to the other side in the second direction and to the other side in the first direction.

In the power storage device of the present invention, the bent portion in the one side region may further include a third bent portion that bends the joint portion to one side in a second direction and one side in the first direction.

In the power storage device of the present invention, the bent portion in the one side region may be bent to the same side around a third direction that is non-parallel to the first direction and the second direction.

In the power storage device of the present invention, the junction may be formed only in the one side region.

In the storage element of the present invention,
The exterior body further includes another side region on the other side in the second direction,
The first exterior material and the second exterior material are joined in the other side region to form a joint,
The joining part may have a plurality of bent parts in the other side area.

In the power storage device according to the aspect of the invention, a tip portion of the joining portion in the other-side region is positioned so as to overlap the accommodation portion in the first direction, and the second end of the accommodation portion and the joining portion in the second direction. It may be located between the part on the other side in the direction.

In the power storage device of the present invention, the joint in the one side region and the joint in the other side region are bent portions having the same number of times counted from the base end of each joint, and are formed in the first direction. May be bent to the opposite side.

In the storage element of the present invention,
The bent portion includes a first bent portion that is a bent portion closest to a base end portion of the joining portion, a second bent portion closer to the distal end portion than the first bent portion, and a distal end portion that is closer to the distal end portion than the second bent portion. A third bent portion close to the portion,
In the first direction, the first bent portion may be located between the second bent portion and the third bent portion.

In the power storage device of the present invention, the bent portion in the other side region is a bent portion closest to a base end of the joint portion, and a first bent portion that bends the joint portion to one side in the first direction. And a second bent portion that bends the joint portion to one side of the second direction and the other side of the first direction.

In the power storage device of the present invention, the bent portion in the other side region may further include a third bent portion that bends the joint portion to the other side in the second direction and to one side in the first direction.

In the power storage device of the present invention, the bent portion in the other side region may be bent to the same side around a third direction that is non-parallel to the first direction and the second direction.

In the power storage device of the present invention, the tip may be covered by the joint including the tip from one side or the other side in the first direction.

In the power storage device of the present invention, the tip may be covered by the joint including the tip from one side and the other side in the second direction.

In the power storage device of the present invention, the length of the joint in the first direction may be equal to or less than the length of the housing in the first direction.

In the power storage device of the present invention, the plurality of first electrodes and the plurality of second electrodes may be alternately stacked in the first direction.

In the power storage device of the present invention, the second exterior material may include a second bulge that forms the housing portion together with the first bulge of the first exterior material.

In the storage element of the present invention,
A tab electrically connected to the first electrode and extending to the outside of the exterior body;
The first exterior material includes a first metal layer and a first insulating layer stacked on the first metal layer,
The second exterior material includes a second insulating layer facing the first insulating layer and a second metal layer stacked on the second insulating layer,
The tab may pass between the first insulating layer and the second insulating layer.

In the power storage device of the present invention, the first exterior material and the second exterior material may be integrally formed.

In the power storage element of the present invention, the first exterior material and the second exterior material may be continuous in another area on the other side in the second direction.

The method for manufacturing a power storage element of the present invention is a method for manufacturing any of the above-described power storage elements,
A step of bending the joint in the one side region a plurality of times.

In the method for manufacturing a power storage device according to the present invention, the step of bending the joint portion in the one side region a plurality of times may include placing the joint portion in the one side region on one side in the first direction and on the other side in the second direction. The method may include a step of bending and a step of bending the joint in the one side region to one side in the first direction.

In the method for manufacturing a power storage device according to the present invention, the step of bending the joint portion in the one side region a plurality of times may include placing the joint portion in the one side region on one side in the first direction and on the other side in the second direction. The step of bending may be included a plurality of times.

In the method for manufacturing a power storage device of the present invention, in the step of bending the bonding portion in the one side region a plurality of times, the bonding portion has a third direction that is non-parallel to the first direction and the second direction as an axis. It may be folded to the same side.

According to the present invention, it is possible to increase the volume energy density while widening the joint of the exterior material.

FIG. 1 is a diagram for describing an embodiment of the present invention, and is a perspective view illustrating a power storage element. FIG. 2 is a plan view showing an electrode body included in the power storage device of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1 and is a diagram for explaining the structure of the electrode of the power storage element and the exterior material. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 1 and is a view for explaining an example of a structure of a joint portion of the exterior material of the power storage element. FIG. 5 is a cross-sectional view illustrating an example of a method for manufacturing a power storage device. FIG. 6 is a cross-sectional view illustrating an example of a method for manufacturing a power storage device. FIG. 7 is a cross-sectional view illustrating an example of a method for manufacturing a power storage device. FIG. 8 is a cross-sectional view illustrating an example of a method for manufacturing a power storage device. FIG. 9 is a cross-sectional view corresponding to FIG. 4 and is a view for explaining a modification of the structure of the joint of the exterior material of the power storage element. FIG. 10 is a diagram illustrating a modification of the exterior body of the power storage element. FIG. 11 is a diagram for describing another modification of the exterior body of the storage element.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale and the vertical and horizontal dimensional ratios and the like are appropriately changed and exaggerated for convenience of understanding.

FIGS. 1 to 8 are views for explaining an embodiment of the electric storage device according to the present invention. FIG. 1 is a perspective view illustrating a specific example of a power storage element. As shown in FIG. 1, the electric storage element 1 includes an exterior body 30, an electrode body 5 housed in a housing portion 35 formed by the exterior body 30, and an external body connected to the electrode body 5 from the inside of the exterior body 30 to the outside. And a tab 4 extending to the outside. As shown in FIGS. 2 and 3, the electrode body 5 has a plurality of first electrodes 10 and second electrodes 20 stacked in the first direction d1. In the example illustrated in FIG. 1, the power storage element 1 has a flat shape in which the first direction d1 that is the thickness direction as a whole is thin, and the second direction d2 that is the short direction and the third direction that is the long direction. It spreads in the direction d3. The first direction d1, the second direction d2, and the third direction d3 are not parallel to each other, and in the illustrated example, the first direction d1, the second direction d2, and the third direction d3 are orthogonal to each other.

In the following, an example in which the electric storage element 1 is a stacked battery, specifically, a lithium ion secondary battery will be described. In this example, the first electrode 10 forms the positive electrode 10X, and the second electrode 20 forms the negative electrode 20Y. However, as can be understood from the description of the operation and effect described below, the embodiment described here is not limited to the lithium ion secondary battery, and the first electrode 10 and the second electrode 20 are not limited to the lithium ion secondary battery. The present invention can be widely applied to the power storage device 1 which is alternately stacked in the first direction d1. The storage element 1 is not limited to a stacked battery, and may be, for example, a wound battery. Even when the storage element 1 is a wound battery, the first electrode 10 and the second electrode 20 are stacked in the first direction d1.

The tab 4 functions as a terminal in the power storage device 1. FIG. 2 is a plan view showing the electrode body 5 included in the electric storage element 1. FIG. 3 shows a cross section taken along the line III-III of FIG. As shown in FIGS. 2 and 3, one (one side of the third direction d3) tab 4 is electrically connected to the positive electrode 10 </ b> X (the first electrode 10) of the electrode body 5. Similarly, the tab 4 on the other side (the other side in the third direction d3) is electrically connected to the negative electrode 20Y (second electrode 20) of the electrode body 5. The tab 4 can be formed using aluminum, nickel, nickel-plated copper, or the like. As shown in FIGS. 1 and 2, the pair of tabs extend from the housing portion 35 inside the exterior body 30 to the outside of the exterior body 30. In addition, as shown in FIG. 3, the tab 4 is provided between the first exterior material 40 and the second exterior material 50 of the exterior body 30 described later, more specifically, the first insulating layer 42 of the first exterior material 40. It passes between the second exterior material 50 and the second insulating layer 52. Further, the space between the exterior body 30 and the tab 4 is sealed in a region where the tab 4 extends.

Next, the electrode body 5 will be described. As shown in FIG. 2, the electrode body 5 has a positive electrode 10X (first electrode 10) and a negative electrode 20Y (second electrode 20). The electrode body 5 has an insulator (not shown) disposed between the positive electrode 10X and the negative electrode 20Y. As shown in FIG. 3, the positive electrode 10X and the negative electrode 20Y are alternately stacked along the first direction d1. The electrode body 5 includes, for example, a total of 20 or more plate-like positive electrodes 10X and negative electrodes 20Y. The electrode body 5 has a flat shape as a whole, has a small thickness in the first direction d1, and extends in a direction non-parallel to the first direction d1. The electrode body 5 extends in a second direction d2 and a third direction d3 orthogonal to the first direction d1. The thickness of the electrode body 5, that is, the length along the first direction d1, is, for example, 4 mm or more and 20 mm or less.

に お い て In the non-limiting example shown in FIG. 2, the positive electrode 10X and the negative electrode 20Y are plate-shaped electrodes having a rectangular outer contour. A second direction d2 non-parallel to the first direction d1 is a short direction (width direction) of the positive electrode 10X and the negative electrode 20Y, and a third direction d3 non-parallel to both the first direction d1 and the second direction d2. , The longitudinal direction of the positive electrode 10X and the negative electrode 20Y. As shown in FIG. 2, the positive electrode 10X and the negative electrode 20Y are shifted from each other in the third direction d3. More specifically, the plurality of positive electrodes 10X are arranged closer to one side in the third direction d3, and the plurality of negative electrodes 20Y are arranged closer to the other side in the third direction d3. As shown in FIG. 3, the positive electrode 10X and the negative electrode 20Y overlap in the first direction d1 at the center in the third direction d3. Further, as shown in FIG. 2, the length of the negative electrode 20Y (second electrode 20) along the second direction d2 (width direction) is equal to the length of the positive electrode 10X (first electrode 10) in the second direction d2. It is longer than the length along. In the illustrated example, the negative electrode 20Y extends from the positive electrode 10X to one side and the other side in the second direction d2. The thickness of the positive electrode 10X and the negative electrode 20Y, that is, the length in the first direction d1 is, for example, 80 μm or more and 200 μm or less, and the length (width) in the short direction, that is, the second direction d2 is, for example, 70 mm or more and 350 mm. The length along the longitudinal direction, that is, the third direction d3 is, for example, 200 mm or more and 950 mm or less.

As shown in FIG. 3, the positive electrode 10X (first electrode 10) includes a positive electrode current collector 11X (first electrode current collector 11) and a positive electrode active material layer provided on the positive electrode current collector 11X. 12X (first electrode active material layer 12). In the lithium ion secondary battery, the positive electrode 10X emits lithium ions when discharging and occludes lithium ions when charging.

正極 As shown in FIG. 3, the positive electrode current collector 11X has a first surface 11a and a second surface 11b facing each other as main surfaces. The positive electrode active material layer 12X is formed on both surfaces of the first surface 11a and the second surface 11b of the positive electrode current collector 11X. The plurality of positive electrodes 10X included in the electrode body 5 have a pair of positive electrode active material layers 12X provided on both sides of the positive electrode current collector 11X, and may be configured identically.

The positive electrode current collector 11X and the positive electrode active material layer 12X can be manufactured by various manufacturing methods using various materials applicable to the power storage element 1 (lithium ion secondary battery). As an example, the positive electrode current collector 11X can be formed of an aluminum foil. The positive electrode active material layer 12X contains, for example, a positive electrode active material, a conductive additive, and a binder serving as a binder. The positive electrode active material layer 12X is formed by applying a positive electrode slurry obtained by dispersing a positive electrode active material, a conductive auxiliary agent, and a binder in a solvent onto a material forming the positive electrode current collector 11X and solidifying the slurry. Can be done. As the positive electrode active material, for example, a lithium metal oxide compound represented by a general formula LiM _x O _y (where M is a metal and x and y are the composition ratio of metal M and oxygen O) is used. Specific examples of the lithium metal oxide compound include lithium cobaltate, lithium nickelate, lithium manganate and the like. Acetylene black or the like can be used as the conductive assistant. As the binder, polyvinylidene fluoride or the like can be used.

正極 As shown in FIG. 2, the positive electrode current collector 11X (the first electrode current collector 11) has a first end region a1 and a first electrode region b1. The positive electrode active material layer 12X (first electrode active material layer 12) is disposed only in the first electrode region b1 of the positive electrode current collector 11X. The first end region a1 and the first electrode region b1 are arranged in the third direction d3. The first end region a1 is located outside the first electrode region b1 in the third direction d3 (left side in FIG. 2). As shown in FIG. 3, the plurality of positive electrode current collectors 11X are joined and electrically connected to each other in the first end region a1 by resistance welding, ultrasonic welding, sticking, fusing, or the like. . In the illustrated example, one tab 4 is electrically connected to the positive electrode current collector 11X in the first end region a1. The tab 4 extends from the electrode body 5 in the third direction d3. On the other hand, as shown in FIG. 2, the first electrode region b1 is located in a region of the negative electrode 20Y facing a later-described negative electrode active material layer 22Y. The width of the positive electrode 10X along the second direction d2 is smaller than the width of the negative electrode 20Y along the second direction d2. With such an arrangement of the first electrode region b1, precipitation of lithium from the negative electrode active material layer 22Y can be prevented.

Next, the negative electrode 20Y (second electrode 20) will be described. The negative electrode 20Y (second electrode 20) includes a negative electrode current collector 21Y (second electrode current collector 21) and a negative electrode active material layer 22Y (second electrode active material layer 22) provided on the negative electrode current collector 21Y. And In the lithium ion secondary battery, the negative electrode 20Y stores lithium ions during discharging and releases lithium ions during charging.

The negative electrode current collector 21Y has a first surface 21a and a second surface 21b facing each other as main surfaces. The negative electrode active material layer 22Y is formed on both surfaces of the first surface 21a and the second surface 21b of the negative electrode current collector 21Y. The plurality of negative electrodes 20Y included in the electrode body 5 have a pair of negative electrode active material layers 22Y provided on both sides of the negative electrode current collector 21Y, and may be configured identically.

(4) The negative electrode current collector 21Y and the negative electrode active material layer 22Y can be manufactured by various manufacturing methods using various materials applicable to the power storage element 1 (lithium ion secondary battery). As an example, the negative electrode current collector 21Y is formed of, for example, a copper foil. The negative electrode active material layer 22Y includes, for example, a negative electrode active material made of a carbon material and a binder functioning as a binder. The negative electrode active material layer 22Y forms, for example, a negative electrode slurry formed by dispersing a negative electrode active material composed of carbon powder, graphite powder, and the like and a binder such as polyvinylidene fluoride in a solvent, as a negative electrode current collector 21Y. It can be produced by coating and solidifying on a material.

As described above, the first electrode region b1 of the positive electrode 10X is located inside the region facing the second electrode region b2 of the negative electrode 20Y (see FIG. 2). That is, the second electrode region b2 extends to a region including the region of the positive electrode 10X facing the positive electrode active material layer 12X. The width of the negative electrode 20Y along the second direction d2 is wider than the width of the positive electrode 10X along the second direction d2. In particular, one end 20a of the negative electrode 20Y in the second direction d2 is located on one side in the second direction d2 of the one end 10a of the positive electrode 10X in the second direction d2. The other end 20b in the two directions d2 is located on the other side in the second direction d2 than the other end 10b of the positive electrode 10X in the second direction d2.

Next, the insulator will be described. The insulator is located between the positive electrode 10X (first electrode 10) and the negative electrode 20Y (second electrode 20). The insulator prevents a short circuit due to contact between the positive electrode 10X (the first electrode 10) and the negative electrode 20Y (the second electrode 20). The insulator preferably has high ion permeability (air permeability), predetermined mechanical strength, and durability with respect to an electrolytic solution, a positive electrode active material, a negative electrode active material, and the like. As such an insulator, for example, a porous body or a nonwoven fabric formed of an insulating material can be used. More specifically, a porous film made of a thermoplastic resin having a melting point of about 80 to 140 ° C. can be used as the insulator. Polyolefin-based polymers such as polypropylene and polyethylene can be used as the thermoplastic resin. An electrolytic solution is sealed in the accommodating portion 35 of the exterior body 30 together with the electrode body 5. By impregnating the insulator made of a porous body or a nonwoven fabric with the electrolyte, the electrolyte is maintained in contact with the electrode active material layers 12 and 22 of the electrodes 10 and 20.

The insulator is located, for example, between any two electrodes 10 and 20 adjacent in the first direction d1. The insulator extends so as to cover the entire area of the positive electrode active material layer 12X of the positive electrode 10X in plan view. Similarly, the insulator extends so as to cover the entire region of the negative electrode active material layer 22Y of the negative electrode 20Y in plan view.

Next, the exterior body 30 will be described with reference to FIGS.

The outer package 30 is a packaging material for sealing the electrode assembly 5. The exterior body 30 forms a housing part 35 for housing the electrode body 5. The exterior body 30 hermetically seals the electrode body 5 and the electrolytic solution in the accommodating portion 35 therein. Further, the exterior body 30 has a first exterior material 40 and a second exterior material 50. The accommodation part 35 is formed by joining the first exterior material 40 and the second exterior material 50 at their peripheral edges.

The housing 35 has a size that is equal to or larger than the size of the electrode body 5 so that the electrode body 5 can be housed. On the other hand, in order to increase the volume energy density of power storage element 1, it is preferable that accommodation portion 35 be small. Furthermore, it is preferable that the dimensions of the housing portion 35 be the same as the dimensions of the electrode body 5. In other words, it is preferable that the exterior body 30 is in contact with the housed electrode body 5. The accommodation portion 35 is formed to have a shape corresponding to the shape of the main electrode body 5. In the illustrated example, the storage section 35 has a rectangular parallelepiped shape. The accommodation portion 35 has, for example, a length along the first direction d1 of 5 mm or more and 25 mm or less, a length along the second direction d2 of 70 mm or more and 400 mm or less, and a length along the third direction d3. Is 200 mm or more and 1000 mm or less.

(4) The first exterior member 40 and the second exterior member 50 are joined to form a joint 60. The first exterior material 40 and the second exterior material 50 may be joined by, for example, an adhesive layer having adhesiveness, or may be joined by welding. When joined by an adhesive layer, the adhesive layer preferably has, in addition to adhesiveness, insulation properties, chemical resistance, thermoplasticity, and the like.For example, polypropylene, modified polypropylene, low-density polypropylene, ionomer, ethylene -Vinyl acetate or the like can be used.

In order to make the housing portion 35 large enough to house the electrode body 5, the first exterior member 40 includes a first bulging portion 45 forming the housing portion 35. The first bulge 45 is located at the center of the first exterior member 40. In the example shown in FIGS. 3 and 4, the housing portion 35 is formed only on one side of the first direction d <b> 1 with respect to a base end portion 62 of the joint portion 60 described below.

よ う As shown in FIG. 3, the first exterior material 40 includes a first metal layer 41 and a first insulating layer 42 laminated on the first metal layer 41. Similarly, the second exterior member 50 includes a second metal layer 51 and a second insulating layer 52 laminated on the second metal layer 51. The first exterior material 40 and the second exterior material 50 are provided such that the first insulating layer 42 and the second insulating layer 52 face each other. A first resin layer 43 having an insulating property is provided on the surface of the first metal layer 41, that is, on the surface of the first metal layer 41 opposite to the surface on which the first insulating layer 42 is laminated. A second resin layer 53 having an insulating property is provided on the surface of the second metal layer 51, that is, on the surface of the second metal layer 51 opposite to the surface on which the second insulating layer 52 is laminated. The first metal layer 41 and the second metal layer 51 preferably have high gas barrier properties and moldability, and for example, an aluminum foil or a stainless steel foil can be used. The first insulating layer 42 and the second insulating layer 52 prevent the electrode body 5 housed in the housing 35 from being electrically connected to the first metal layer 41 and the second metal layer 51. As the first insulating layer 42 and the second insulating layer 52, for example, polypropylene or the like can be used. The first resin layer 43 and the second resin layer 53 are, for example, thin-film nylon layers. As shown in FIG. 3, the tab 4 passes between the first insulating layer 42 and the second insulating layer 52 in the third direction d3. The thickness of the first packaging material 40 and the thickness of the second packaging material 50 are preferably, for example, not less than 100 μm and not more than 300 μm. The first exterior member 40 and the second exterior member 50 may be made of the same material and may be the same, or may be different from each other in at least one of the material and the configuration.

(4) The joining portion 60 is formed by joining the first exterior material 40 and the second exterior material 50, and secures the airtightness of the housing portion 35. It is preferable that the strength of the joint portion 60 be high so that the airtightness of the housing portion 35 is not lost due to breakage of the joint portion 60 or the like. In order to increase the strength of the joint 60, the length (width) along the joint 60 is preferably long. In the present embodiment, the length along the joint 60 is, for example, 5 mm or more and 20 mm or less.

FIG. 4 shows an example of the exterior body 30 in a cross section along the line IV-IV in FIG. As shown in FIG. 4, the exterior body 30 includes one side region 30a on one side of the second direction d2 and another side region 30b on the other side of the second direction d2. The one side region 30a and the other side region 30b are peripheral portions of the exterior body 30. Therefore, the first exterior material 40 and the second exterior material 50 of the exterior body 30 are joined in the one side region 30a and the other side region 30b.

The joint 60 has a plurality of bent portions 70 in the one side region 30a and the other side region 30b, respectively. In the example shown in FIG. 4, the joint portion 60 has three bent portions 70 in the one side region 30a and the other side region 30b, respectively. That is, the bent portion 70 includes a first bent portion 71 which is a bent portion closest to the base end portion 62 of the joint portion 60 and a first bent portion along the joint portion 60 in the one side region 30a and the other side region 30b. A second bent portion 72 closer to the distal end portion 61 than the portion 71 and a third bent portion 73 closer to the distal end portion 61 of the joint portion 60 than the second bent portion 72 along the joint portion 60 are included. In other words, the bent portion 70 includes the first bent portion 71, the second bent portion 72, and the third bent portion 73 in this order from the base end portion 62 to the distal end portion 61 along the joint portion 60. .

Here, the distal end portion 61 of the joint portion 60 is a portion of the joint portion 60 that is the most distant from the housing portion 35 along the joint portion 60. Further, the base end portion 62 of the joining portion 60 is a portion of the joining portion 60 closest to the accommodation portion 35 along the joining portion 60.

第 The first bent portion 71 in the one side region 30a and the other side region 30b bends the joint portion 60 to one side in the first direction d1. In the example shown in FIG. 4, the joining portion 60 extends from the first bent portion 71 to one side of the first direction d1 when going from the base end portion 62 to the distal end portion 61 along the joining portion 60. That is, in the first bent portion 71, the portion on the distal end portion 61 side along the joining portion 60 faces one side in the first direction d1 with respect to the portion on the proximal end portion 62 side along the joining portion 60. It is bent.

The second bent portion 72 in the one side region 30a bends the joint portion 60 to the other side of the second direction d2 and the other side of the first direction d1. In the example shown in FIG. 4, when the joining portion 60 in the one side region 30a moves from the base end portion 62 to the tip end portion 61 along the joining portion 60, the other side of the second bent portion 72 in the second direction d2. The first direction d1 is folded back from one side to the other side while being bent. That is, in the second bent portion 72 in the one side region 30 a, the portion on the distal end portion 61 side along the joint portion 60 is different from the portion on the proximal end portion 62 side along the joint portion 60 in the second direction d2. It is folded back in the first direction d1 so as to face the other side.

{Circle around (2)} The second bent portion 72 in the other side region 30b bends the joint portion 60 to one side of the second direction d2 and the other side of the first direction d1. In the example shown in FIG. 4, the joining portion 60 in the other side region 30 b moves from the base end portion 62 to the leading end portion 61 along the joining portion 60, and the one side of the second bent portion 72 in the second direction d <b> 2. The first direction d1 is folded back from one side to the other side while being bent. In other words, in the second bent portion 72 in the other side region 30b, the portion on the distal end portion 61 side along the joint portion 60 is different from the portion on the proximal end portion 62 side along the joint portion 60 in the second direction d2. It is folded in the first direction d1 so as to face one side.

３The third bent portion 73 in the one side region 30a bends the joint portion 60 to one side of the second direction d2 and one side of the first direction d1. In the example shown in FIG. 4, the joining portion 60 in the one side region 30a moves from the base end portion 62 to the distal end portion 61 along the joining portion 60, and the third bent portion 73 forms one side of the second direction d2. The first direction d1 is folded back from the other side to one side while being bent. That is, in the third bent portion 73 in the one side region 30 a, the portion on the distal end portion 61 side along the joint portion 60 is different from the portion on the proximal end portion 62 side along the joint portion 60 in the second direction d2. It is folded in the first direction d1 so as to face one side.

３ The third bent portion 73 in the other side region 30b bends the joint portion 60 to the other side of the second direction d2 and to one side of the first direction d1. In the example shown in FIG. 4, when the joining portion 60 in the other side region 30 b goes from the base end portion 62 to the tip end portion 61 along the joining portion 60, the other side of the third bent portion 73 in the second direction d2. While extending from the other side in the first direction d1 to one side. That is, in the third bent portion 73 in the other side region 30b, the portion on the distal end portion 61 side along the joint portion 60 is different from the portion on the proximal end portion 62 side along the joint portion 60 in the second direction d2. It is folded back in the first direction d1 so as to face the other side.

折 り The bent portion 70 in the one side region 30a is bent to the same side around the third direction d3, and the bent portion 70 in the other side region 30b is bent to the same side around the third direction d3. In the example shown in FIG. 4, the first bent portion 71, the second bent portion 72, and the third bent portion 73 in the one side region 30a are clockwise (about the third direction d3 (the front-back direction of the paper)). Clockwise). That is, the portion on the distal end portion 61 side along the joining portion 60 is bent clockwise (clockwise) with respect to the portion on the proximal end portion 62 side along the joining portion 60. Similarly, the first bent portion 71, the second bent portion 72, and the third bent portion 73 in the other side region 30b are bent counterclockwise (counterclockwise) around the third direction d3 (the front-rear direction in the drawing). Have been. That is, the portion on the distal end portion 61 side along the joining portion 60 is bent counterclockwise (counterclockwise) with respect to the portion on the proximal end portion 62 side along the joining portion 60.

In FIG. 4, the first insulating layer 42 and the second insulating layer 52, the first resin layer 43, and the second resin layer 53 are not shown. In addition, at the distal end portion 61 of the joining portion 60, the first metal layer 41 of the first exterior material 40 is not covered with the first insulating layer 42 and the first resin layer 43 and is exposed, and the second exterior material is exposed. The 50 second metal layer 51 is not covered with the second insulating layer 52 and the second resin layer 53 and is exposed.

The bent portion 70 is not limited to the illustrated example, and may include four or more bent portions. Further, the number of the bent portions 70 in the one side region 30a may be different from the number of the bent portions 70 in the other side region 30b.

こ と Because the joint portion 60 is bent by the plurality of bent portions 70, the distal end portion 61 of the joint portion 60 in the one side region 30a is positioned so as to overlap the accommodation portion 35 in the first direction d1. In other words, in the first direction d1, the distal end portion 61 does not protrude from the storage portion 35. Further, the distal end portion 61 of the joining portion 60 in the one side region 30a is located between the accommodation portion 35 in the second direction d2 and the portion of the joining portion 60 that is the one side in the second direction d2. In other words, in the second direction d2, the distal end portion 61 does not protrude to one side from other portions of the joint portion 60. In addition, in the example shown in FIG. 4, the portion on the one side in the second direction d2 of the joining portion 60 is a portion between the first bent portion 71 and the second bent portion 72 of the joining portion 60. It is.

Similarly, the distal end portion 61 of the joint portion 60 in the other side region 30b is located so as to overlap the accommodation portion 35 in the first direction d1. In other words, in the first direction d1, the distal end portion 61 does not protrude from the storage portion 35. Further, the distal end portion 61 of the joining portion 60 in the other side region 30b is located between the accommodation portion 35 in the second direction d2 and the portion of the joining portion 60 that is the most other side in the second direction d2. In other words, in the second direction d2, the tip portion 61 does not protrude to the other side from the other portion of the joint 60. In addition, in the example illustrated in FIG. 4, the part on the other side in the second direction d2 of the joint 60 is the part between the first bent part 71 and the second bent part 72 of the joint 60. It is.

It is preferable that the distal end portion 61 is surrounded by the joint portion 60 because the joint portion 60 has such a plurality of bent portions 70. The distal end portion 61 is covered with the joining portion 60 including the distal end portion 61 from one side or the other side of the first direction d1, or from one side of the first direction d1 in the example shown in FIG. Further, the distal end portion 61 is covered with the joining portion 60 including the distal end portion 61 from one side and the other side in the second direction d2.

Further, since the joint portion 60 is bent by the plurality of bent portions 70, the length of the joint portion 60 in the first direction d1 is less than or equal to the length of the housing portion 35 in the first direction d1. Furthermore, since the joining portion 60 has the plurality of bent portions 70, the length of the joining portion 60 in the second direction d2 of the joining portion 60 is the length from the base end portion 62 to the distal end portion 61 along the joining portion 60. It is shorter than it is.

Next, an example of a method for manufacturing the power storage device 1 will be described with reference to FIGS.

First, as shown in FIG. 5, the electrode body 5 is disposed between the first exterior material 40 and the second exterior material 50, and the peripheral edges of the first exterior material 40 and the second exterior material 50 are joined. The housing part 35 is formed by the joined first exterior material 40 and the second exterior material 50, and the electrode body 5 is accommodated in the accommodation part 35. A joining portion 60 formed by joining the first exterior material 40 and the second exterior material 50 extends from the base end 62 to the distal end 61 in one side region 30a of the exterior body 30 to one side in the second direction d2. In the other side region 30 b of the exterior body 30, it extends from the base end portion 62 to the tip end portion 61 on the other side in the second direction d <b> 2.

Next, the joint 60 in the one side region 30a is bent a plurality of times. Specifically, first, as shown by the arrow in FIG. 6, the joint portion 60 in the one side region 30a is bent to one side of the first direction d1 and the other side of the second direction d2. In other words, the joint portion 60 in the one side region 30a is folded from one side of the second direction d2 to the other side while being bent to one side of the first direction d1. That is, in the second direction d2, the portion on the distal end portion 61 side along the joining portion 60 is directed to one side in the first direction d1 with respect to the portion on the proximal end portion 62 side along the joining portion 60. Will be folded back. Here, the bent portion becomes the third bent portion 73 of the bent portion 70. By bending the joint portion 60, the distal end portion 61 is located between the base end portion 62 and the third bent portion 73 in the second direction d2.

Next, as shown by an arrow in FIG. 7, the joint 60 between the third bent portion 73 and the base end portion 62 in the one side region 30 a is connected to one side of the first direction d1 and the other side of the second direction d2. Bend again. In other words, the joint 60 in the one side region 30a is folded back from one side in the second direction d2 to the other side while being bent in one side in the first direction d1. That is, in the second direction d2, the portion on the distal end portion 61 side along the joining portion 60 is directed to one side in the first direction d1 with respect to the portion on the proximal end portion 62 side along the joining portion 60. Will be folded back. The portion bent here becomes the second bent portion 72 of the bent portion 70. By bending the joint portion 60, the distal end portion 61 is covered by the joint portion 60 including the distal end portion 61 from one side and the other side of the first direction d1 and from one side of the second direction d2.

(8) Further, as shown by the arrow in FIG. 8, the joint portion 60 between the second bent portion 72 and the base end portion 62 in the one side region 30a is bent to one side in the first direction d1. In other words, in the one-side region 30a, the portion on the distal end portion 61 side along the joint portion 60 faces one side in the first direction d1 with respect to the portion on the base end portion 62 side along the joint portion 60. The joint 60 is bent. Here, the bent portion becomes the first bent portion 71 of the bent portion 70. By bending the joint portion 60, the side that covers the distal end portion 61 becomes one side of the first direction d1, one side of the second direction, and the other side. Therefore, the distal end portion 61 is located between the accommodation portion 35 and the portion of the joining portion 60 that is the most side in the second direction d2 in the second direction d2. In addition, the joint portion 60 is bent at a position where the length between the first bent portion 71 and the second bent portion 72 is equal to or less than the length of the housing portion 35 in the first direction d1. Therefore, the distal end portion 61 of the joining portion 60 is positioned so as to overlap in the first direction d1.

The joints 60 in the one side region 30a are all bent to the same side around the third direction d3, specifically, to one side in the first direction d1.

By the above steps, the joint portion 60 in the one side region 30a is bent plural times. In the examples shown in FIGS. 5 to 8, the method of manufacturing the joint 60 in the one side region 30 a of the exterior body 30 is described. Can also be manufactured by the same manufacturing method. The bonding portion 60 in the other side region 30b of the exterior body 30 may be formed at the same time as the bonding portion 60 in the one side region 30a of the exterior body 30, or separately from the bonding portion 60 in the one side region 30a of the exterior body 30. May be formed. On one side and the other side of the second direction d2, the junction 60 is bent a plurality of times, whereby the electric storage device 1 shown in FIG. 4 is manufactured.

By the way, in power storage element 1 of the present embodiment, joining portion 60 has a plurality of bent portions 70 in one side region 30a. The length of the joint portion 60 in the second direction d2 can be shortened by bending the joint portion 60 by the bent portion 70. Further, in the present embodiment, the distal end portion 61 of the joining portion 60 in the one side region 30a is located so as to overlap with the accommodation portion 35 in the first direction d1, and the accommodation portion 35 and the joining portion 60 in the second direction d2. In the second direction d2. In other words, the distal end portion 61 of the joining portion 60 in the one side region 30a does not protrude in the first direction d1 and the second direction d2. The joining portion 60 is bent and folded in the second direction d2, and is folded and folded in the first direction d1 or is disposed only at a position overlapping the accommodation portion 35. That is, the length of the joint 60 in the first direction d1 and the second direction d2 is reduced. In such a case, even if the width (length along the bonding portion 60) of the bonding portion 60 of the exterior body 30 is increased, the volume occupied by the power storage element 1 does not easily increase. Therefore, it is possible to suppress a decrease in the volume energy density while increasing the width of the joint 60 of the exterior body 30.

で は In the present embodiment, the length of the joint portion 60 in the first direction d1 is equal to or less than the length of the housing portion 35 in the first direction d1. That is, the joint 60 does not protrude from the housing 35 in the first direction d1. In other words, the joint 60 does not increase the volume occupied by the power storage element 1 in the first direction d1. By bending such a joint portion 60, the volume occupied by the power storage element 1 can be prevented from increasing, and a decrease in volume energy density can be suppressed.

{Circle around (1)} At the distal end portion 61 of the joint 60, the first metal layer 41 of the first exterior material 40 and the second metal layer 51 of the second exterior material 50 are exposed. For this reason, when a conductor such as a metal member or dew condensation water comes into contact with the distal end portion 61 of the joining portion 60, a power supply outside the power storage element 1 and the first metal layer 41 and the second metal layer 51 and the first metal layer 41 and the second metal layer 51 are electrically connected to each other. When a voltage is applied to the first metal layer 41 and the second metal layer 51, the electrolyte contained in the outer package 30 due to damage of the first insulating layer 42 and the second insulating layer 52 or the like is removed from the first metal layer 41. When the first metal layer 41 and the second metal layer 51 are in direct contact with each other, the first metal layer 41 and the second metal layer 51 may be corroded. When the first metal layer 41 and the second metal layer 51 are corroded, the durability of the first exterior material 40 and the second exterior material 50 is reduced, and there is a possibility that the electrode body 5 and the electrolyte cannot be sealed. Therefore, it is desired that the tip end portion 61 of the joining portion 60 be hardly contacted with a conductor from the outside. In the present embodiment, the distal end portion 61 of the joining portion 60 in the one side region 30a is located so as to overlap the accommodation portion 35 in the first direction d1, and the second portion of the accommodation portion 35 and the joining portion 60 in the second direction d2. It is located between the part on the one side in the direction d2. In other words, the tip portion 61 of the joining portion 60 in the one side region 30a is not exposed in the first direction d1 and the second direction d2. For this reason, the distal end portion 61 of the joining portion 60 of the exterior body 30 is less likely to come into contact with the conductor from the outside, and the durability of the first exterior material 40 and the second exterior material 50 is not easily reduced.

In particular, in the present embodiment, the distal end portion 61 is covered from one side in the first direction d1 by the joining portion 60 including the distal end portion 61, and is connected from one side and the other side in the second direction d2. It is covered by a joint 60 including 61. Therefore, in the first direction d1 and the second direction d2, the distal end portion 61 is less likely to come into contact with the conductor from the outside, and the durability of the first exterior material 40 and the second exterior material 50 is less likely to decrease. Has become.

In order to make the joining portion 60 in the one side region 30a have such a configuration, in the present embodiment, the bent portion 70 in the one side region 30a is a first bent portion that bends the joining portion 60 to one side in the first direction d1. 71, a second bent portion 72 for bending the joint portion 60 to the other side of the second direction d2 and the other side of the first direction d1, and a joint portion 60 to one side of the second direction d2 and one side of the first direction d1. And a third bent portion 73 that bends the third bent portion. The first bent portion 71 is a bent portion closest to the base end portion 62 of the joint portion 60, and the bent portion 70 extends from the base end portion 62 toward the distal end portion 61 along the joint portion 60. 71, a second bent portion 72 and a third bent portion 73 are included in this order. In particular, in the present embodiment, the bent portion 70 is bent to the same side (clockwise in FIG. 4) about the third direction d3 as an axis. Since such a bent portion 70 is easily formed, the volume occupied by the power storage element 1 is hardly increased, and the power storage element 1 in which the conductor is not easily brought into contact with the distal end portion 61 from the outside can be easily manufactured. .

In addition, in power storage element 1 of the present embodiment, bonding portion 60 has a plurality of bent portions 70 also in other side region 30b. Therefore, it is possible to suppress a decrease in the volume energy density while increasing the width of the joint 60 of the exterior body 30. Further, the distal end portion 61 of the joining portion 60 in the other side region 30b is located so as to overlap with the accommodation portion 35 in the first direction d1, and the accommodation portion 35 and the joining portion 60 most in the second direction d2 in the second direction d2. It is located between the other side. Therefore, the distal end portion 61 of the joining portion 60 is less likely to come into contact with the conductor from the outside, and the short circuit of the electrode body 5 is less likely to occur.

In the present embodiment, the bent portion 70 in the other side region 30b is formed by the first bent portion that bends the bonded portion 60 to one side in the first direction d1 in order to make the bonding portion 60 in the other side region 30b have such a configuration. 71, a second bent portion 72 for bending the joining portion 60 to one side of the second direction d2 and the other side of the first direction d1, and a joining portion 60 to the other side of the second direction d2 and one side of the first direction d1. And a third bent portion 73 that bends the third bent portion. The first bent portion 71 is a bent portion closest to the base end portion 62 of the joint portion 60, and the bent portion 70 extends from the base end portion 62 toward the distal end portion 61 along the joint portion 60. 71, a second bent portion 72 and a third bent portion 73 are included in this order. In particular, in the present embodiment, the bent portion 70 is bent to the same side (counterclockwise in FIG. 4) about the third direction d3 as an axis. Since such a bent portion 70 is easy to form, the volume occupied by the power storage element 1 is hard to increase, and the power storage element 1 in which the external conductor does not easily come into contact with the distal end portion 61 can be easily manufactured. .

When the plurality of first electrodes 10 and the plurality of second electrodes 20 are alternately stacked in the first direction d1, the shape of the accommodating portion 35 formed according to the shape of the electrode body 5 is changed to a curved surface. It can be made into a rectangular parallelepiped without having. That is, the shape of the first bulging portion 45 of the first exterior material 40 forming the housing portion 35 can be formed only by a flat surface. For this reason, by bending the joint 60 along the side surface of the first bulging portion 45, the step of bending the joint 60 so as to face one side of the first direction d1 as shown in FIG. Can be done.

As described above, the electric storage element 1 of the present embodiment forms the electrode body 5 having the first electrode 10 and the second electrode 20 stacked in the first direction d1 and the housing 35 that houses the electrode body 5. The exterior body 30 includes a one-side region 30a on one side of a second direction d2 that is not parallel to the first direction d1. It has a first exterior material 40 including a bulging portion 45 and a second exterior material 50 joined to the first exterior material 40 in one side region 30a to form a joined portion 60. The side region 30a has a plurality of bent portions 70, and the distal end portion 61 of the joining portion 60 in the one side region 30a is positioned so as to overlap with the housing portion 35 in the first direction d1, and is located in the second direction d2. The one side of the joining portion 60 in the second direction d2 is Located between the parts. According to such a power storage element 1, while the width of the joint 60 is increased, the length of the joint 60 in the first direction d1 and the second direction d2 can be reduced. That is, it is possible to increase the volume energy density while widening the joint of the exterior material.

In addition, according to such a power storage element 1, the distal end portion 61 of the joining portion 60 in the one side region 30a is not exposed in the first direction d1 and the second direction d2. Since the distal end portion 61 of the joining portion 60 of the exterior body 30 is less likely to come into contact with the conductor from outside, a short circuit of the electrode body 5 is less likely to occur.

Various changes can be made to the above-described embodiment.

For example, as shown in FIG. 9, similarly to the first exterior material 40, the second exterior material 50 may include the second bulging portion 55. The second bulging portion 55 is located at the center of the second exterior material 50 and forms the accommodating portion 35 together with the first bulging portion 45. In this case, the accommodating portions 35 are formed on one side and the other side of the base end 62 of the joint 60 in the first direction d1. As shown in FIG. 9, the joint portion 60 can extend on both sides of the base end portion 62 on one side and the other side in the first direction d1. In other words, the first bent portion 71 can be located between the second bent portion 72 and the third bent portion 73 in the first direction d1.

Further, the joint 60 in the one side region 30a and the joint 60 in the other side region 30b may be bent in the same direction with respect to the first direction d1, but as shown in FIG. Preferably, it is bent in the opposite direction to d1. More specifically, the joining portion 60 in the one side region 30a and the joining portion 60 in the other side region 30b are bent portions 70 having the same number of times as counted from the base end portion 62 of each joining portion 60 in the first direction d1. Is preferably bent to the opposite side of the above. In the example shown in FIG. 9, the joint portion 60 in the one side region 30a is bent to one side in the first direction d1 at the first bent portion 71, and is connected to the other side of the first direction d1 at the second bent portion 72. The first bent portion 73 is bent to one side in the first direction d1. On the other hand, the joint portion 60 in the other side region 30b is bent at the first bent portion 71 to the other side of the first direction d1, and is bent at the second bent portion 72 to one side of the first direction d1. The third bent portion 73 is bent to the other side in the first direction d1. When the bonding portion 60 is bent in this manner, in the step of bending the bonding portion 60, a force is easily applied evenly in the first direction d1, and thus the power storage element 1 is placed on one side or the other side of the first direction d1. Can be prevented from being deformed into a shape conforming to.

In addition, in the above-described embodiment, the first exterior material 40 and the second exterior material 50 are separate members. However, as shown in FIG. 10, the first exterior material 40 and the second exterior material 50 may be formed integrally. That is, the first exterior material 40 and the second exterior material 50 may be continuous members. FIG. 10 is a cross-sectional view illustrating a modification of the exterior body 30 in a plane parallel to the first direction d1 and the second direction d2.

In the example shown in FIG. 10, the exterior body 30 is formed of one sheet-like member that has been folded back at the folded portion 31. In this case, as is well shown in FIG. 10, one side of the exterior body 30 in the first direction d1 is the first exterior material 40 with the folded portion 31 as a reference, and the other side in the first direction d1 is the second exterior material 40. It is an exterior material 50. In the example shown in FIG. 10, the first exterior material 40 and the second exterior material 50 are continuous on the other side in the second direction d2. According to such an exterior body 30, the electrode body 5 and the electrolytic solution can be more securely sealed in the housing portion 35 on the other side in the second direction d2. In addition, since the folded portion 31 is formed with high accuracy, the exterior body 30 can be folded with high accuracy. That is, the first exterior member 40 and the second exterior member 50 can be accurately positioned. By accurately aligning the first exterior member 40 and the second exterior member 50, the strength of the joint portion 60 can be increased and the airtightness of the housing portion 35 can be ensured.

Further, when the first exterior material 40 and the second exterior material 50 are integrally formed, as shown in FIG. 4 of the above-described embodiment, the first exterior material 40 and the second exterior material 50 May be formed in both the one side region 30a on one side of the second direction d2 and the other side region 30b on the other side, but as shown in FIG. The joint 60 with the second exterior material 50 may be formed only in the one side region 30a on one side in the second direction d2. That is, on the other side of the second direction d2, the first exterior material 40 and the second exterior material 50 are continuous, so that the joining portion 60 may not be formed. In this case, since the first exterior material 40 and the second exterior material 50 are continuous, airtightness can be ensured in the second direction d2, and the volume is reduced because the joint portion 60 is not formed. It can be made smaller to increase the volume energy density.

Note that while some modifications to the above-described embodiment have been described above, a plurality of modifications may be combined as appropriate and applied.

REFERENCE SIGNS LIST 1 power storage element 4 tab 5 electrode body 10 first electrode 20 second electrode 30 exterior body 30 a one side area 30 b other side area 35 housing part 40 first exterior material 41 first metal layer 42 first insulating layer 45 first bulge Part 50 second exterior material 51 second metal layer 52 second insulating layer 55 second bulging part 60 joint part 61 tip part 62 base end part 70 bent part 71 first bent part 72 second bent part 73 third bent part

Claims (24)

1. An electrode body having a first electrode and a second electrode stacked in a first direction;
   An outer body forming a housing part for housing the electrode body,
   The exterior body includes a one-side region on one side in a second direction that is not parallel to the first direction,
   The exterior body includes: a first exterior material including a first bulging portion forming the housing portion; and a second exterior material joined to the first exterior material in the one side region to form a joint. Have
   The joint has a plurality of bent portions in the one side region,
   The distal end of the joint in the one side region is positioned so as to overlap with the accommodation portion in the first direction, and is the one side in the second direction of the accommodation portion and the joint in the second direction. A power storage element located between the two.
2. The bent portion in the one side region is a bent portion closest to a base end portion of the joint portion, a first bent portion that bends the joint portion to one side in the first direction, and the joint portion includes: The power storage element according to claim 1, further comprising: a second bent portion bent to the other side in the second direction and to the other side in the first direction.
3. The power storage device according to claim 2, wherein the bent portion in the one side region further includes a third bent portion that bends the joint portion to one side in the second direction and one side in the first direction.
4. The said bent part in the said one side area | region is bent to the same side centering on the 3rd direction non-parallel to the said 1st direction and the said 2nd direction, The Claims 1 thru | or 3 characterized by the above-mentioned. Storage element.
5. The power storage element according to any one of claims 1 to 4, wherein the junction is formed only in the one side region.
6. The exterior body further includes another side region on the other side in the second direction,
   The first exterior material and the second exterior material are joined in the other side region to form a joint,
   5. The electric storage device according to claim 1, wherein the joint has a plurality of bent portions in the other side region. 6.
7. The distal end of the joining portion in the other side region is located so as to overlap with the accommodation portion in the first direction, and is the other end in the second direction of the accommodation portion and the joining portion in the second direction. The power storage device according to claim 6, wherein the power storage device is located between the power storage device and a portion.
8. The joining portion in the one side region and the joining portion in the other side region are bent portions having the same number of times counted from the base end of each joining portion, and are bent to the opposite side in the first direction. The power storage device according to claim 6, wherein
9. The bent part in the other side area is a bent part closest to a base end of the joint part, and a first bent part that bends the joint part to one side in the first direction; The power storage element according to claim 6, further comprising: a second bent portion bent to one side in a second direction and the other side in the first direction.
10. The power storage device according to claim 9, wherein the bent portion in the other side region further includes a third bent portion that bends the joint portion to the other side in the second direction and to one side in the first direction.
11. The said bent part in the said other side area | region is bent to the same side centering | focusing on the 3rd direction non-parallel to the said 1st direction and the said 2nd direction. Storage element.
12. The bent portion includes a first bent portion that is a bent portion closest to a base end portion of the joining portion, a second bent portion closer to the distal end portion than the first bent portion, and a distal end portion that is closer to the distal end portion than the second bent portion. A third bent portion close to the portion,
    The power storage element according to claim 1, wherein the first bent portion is located between the second bent portion and the third bent portion in the first direction.
13. The power storage element according to any one of claims 1 to 12, wherein the tip is covered by the joining portion including the tip from one side or the other side in the first direction.
14. The power storage element according to any one of claims 1 to 13, wherein the tip is covered by the joint including the tip from one side and the other side in the second direction.
15. The power storage element according to any one of claims 1 to 14, wherein a length of the joint in the first direction is equal to or less than a length of the housing in the first direction.
16. The power storage device according to any one of claims 1 to 15, wherein the plurality of first electrodes and the plurality of second electrodes are alternately stacked in the first direction.
17. The energy storage device according to any one of claims 1 to 16, wherein the second exterior material includes a second bulge that forms the housing portion together with the first bulge of the first exterior material.
18. A tab electrically connected to the first electrode and extending to the outside of the exterior body;
    The first exterior material includes a first metal layer and a first insulating layer stacked on the first metal layer,
    The second exterior material includes a second insulating layer facing the first insulating layer and a second metal layer stacked on the second insulating layer,
    The electric storage device according to any one of claims 1 to 17, wherein the tub passes between the first insulating layer and the second insulating layer.
19. The power storage element according to any one of claims 1 to 18, wherein the first exterior material and the second exterior material are integrally formed.
20. 20. The power storage device according to claim 19, wherein the first exterior material and the second exterior material are continuous on the other side in the second direction.
21. It is a manufacturing method of the electric storage element as described in any one of Claims 1 thru | or 20, Comprising:
    A method for manufacturing a power storage device, comprising a step of bending the joint portion in the one side region a plurality of times.
22. Bending the joint in the one side region a plurality of times; bending the joint in the one side region to one side in the first direction and the other side in the second direction; and 22. The method for manufacturing a power storage device according to claim 21, further comprising: bending a joint portion to one side of the first direction.
23. 23. The step of bending the joint in the one side region a plurality of times includes bending the joint in the one side region to one side of the first direction and the other side of the second direction a plurality of times. 3. The method for manufacturing a power storage device according to claim 1.
24. 22. The step of bending the joint in the one side region a plurality of times, wherein the joint is bent to the same side around a third direction that is non-parallel to the first direction and the second direction. 24. The method for manufacturing a power storage device according to claim 23.

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