JP7201482B2 - Storage element and method for manufacturing storage element - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric storage element and a method for manufacturing an electric storage element.

BACKGROUND ART Laminated batteries and wound batteries, in which positive electrodes and negative electrodes are alternately laminated, are widely used as electric storage elements, as proposed in Patent Document 1, for example. An example of such a laminated battery is a lithium ion secondary battery. One of the features of the lithium ion secondary battery is that it has a large capacity compared to other types of stacked batteries. Lithium-ion secondary batteries having such characteristics are expected to spread further in various applications such as on-vehicle applications and stationary housing applications.

By the way, in a laminated battery represented by a lithium ion secondary battery, when the length of the negative electrode active material layer of the negative electrode along the longitudinal direction is longer than the length of the positive electrode active material layer of the positive electrode along the longitudinal direction There is In this case, the negative electrode active material layer of the negative electrode has a region extending outward from the ends of the positive electrode active material layer of the positive electrode in the longitudinal direction.

On the other hand, when the negative electrode active material layer of the negative electrode has a region extending outside the end portion of the positive electrode active material layer of the positive electrode, the negative electrode is in contact with the adjacent positive electrode in the stacking direction in the region. may be short-circuited.

JP 2011-108624 A

The present invention has been made in consideration of such points, and provides an electric storage element and a method for manufacturing an electric storage element capable of suppressing short-circuiting of positive and negative electrodes adjacent to each other in the stacking direction. for the purpose.

The storage device of the present invention is
a first electrode;
a second electrode alternately stacked with the first electrode in a first direction;
an insulating sheet disposed between the first electrode and the second electrode adjacent in the first direction;
The first electrode includes a first electrode current collector including an effective region and a connection region adjacent to the effective region, and a first electrode active material layer laminated on the effective region of the first electrode current collector. , has
The second electrode includes a second electrode current collector including an effective region and a connection region adjacent to the effective region, and a second electrode active material layer laminated on the effective region of the second electrode current collector. , has
the second electrode active material layer has an extension region extending outward from an end portion of the first electrode active material layer in a second direction non-parallel to the first direction;
The insulating sheet covers the extension region of the second electrode active material layer,
The insulating sheets that are adjacent in the first direction are joined to each other via joints,
At least a portion of the junction is a power storage element formed at a position overlapping with the extension region of the second electrode active material layer in the second direction.

In the electric storage device of the present invention,
A plurality of the insulating sheets,
Each of the insulating sheets may be joined to each other at the joining portion.

In the electric storage device of the present invention,
The insulating sheets are alternately folded in a third direction non-parallel to both the first direction and the second direction,
In the joint portion, portions of the insulating sheet that are adjacent in the first direction may be joined together.

In the electric storage device of the present invention,
A plurality of the first electrodes and the second electrodes may be provided.

In the electric storage device of the present invention,
A length along the second direction of a portion of the joint portion that overlaps the extension region in the second direction may be 0.5 mm or more and 4.0 mm or less.

In the electric storage device of the present invention,
A length of the joint portion along the second direction may be 0.5 mm or more and 4.0 mm or less.

In the electric storage device of the present invention,
The joints may be formed on both sides of the second electrode in a third direction non-parallel to both the first direction and the second direction.

In the electric storage device of the present invention,
A length of the extension region along the second direction may be 0.5 mm or more and 4.0 mm or less.

In the electric storage device of the present invention,
The insulating sheet may be made of a resin composition containing at least one of polypropylene and polyethylene.

In the electric storage device of the present invention,
The entire joint portion may overlap the extension region in the second direction.

In the electric storage device of the present invention,
A first insulating member may be provided at a position of the connecting region of the first electrode current collector that overlaps with the extending region in the second direction.

In the electric storage device of the present invention,
The first insulating member may be a layer or tape containing a metal oxide.

In the electric storage device of the present invention,
A second insulating member may be provided between the first electrode and the second electrode adjacent in the first direction and at a position overlapping the extension region in the second direction.

In the electric storage device of the present invention,
The second insulating member may be a layer or tape containing a metal oxide.

In the electric storage device of the present invention,
Ten or more of the first electrodes and the second electrodes may be included, respectively.

The method for manufacturing an electric storage element of the present invention comprises:
a first electrode having a first electrode current collector including an effective region and a connection region adjacent to the effective region; a second electrode having a second electrode current collector including a region and a connection region adjacent to the effective region; and a second electrode active material layer laminated on the effective region of the second electrode current collector; and an insulating sheet. a lamination step of laminating the insulating sheet so that it is arranged between the first electrode and the second electrode adjacent in the first direction;
a bonding step of bonding the insulating sheets adjacent to each other in the first direction via a bonding portion;
the second electrode active material layer has an extension region extending outward from an end portion of the first electrode active material layer in a second direction non-parallel to the first direction;
In the lamination step, the extended region of the second electrode active material layer is covered with the insulating sheet;
In the method of manufacturing a power storage element, in the bonding step, at least part of the bonding portion is formed at a position overlapping the extension region of the second electrode active material layer in the second direction.

In the method for manufacturing an electric storage element of the present invention,
In the lamination step, a plurality of the insulating sheets are laminated,
In the joining step, the insulating sheets may be joined together.

In the method for manufacturing an electric storage element of the present invention,
In the lamination step, the insulating sheets are alternately folded in a third direction that is non-parallel to both the first direction and the second direction;
In the bonding step, adjacent portions of the insulating sheets in the first direction may be bonded together.

In the method for manufacturing an electric storage element of the present invention,
In the bonding step, the bonding portions may be formed on both sides of the extension region in a third direction non-parallel to both the first direction and the second direction.

In the method for manufacturing an electric storage element of the present invention,
In the laminating step, a first insulating member may be arranged at a position of the first electrode current collector that overlaps the extension region in the second direction.

In the method for manufacturing an electric storage element of the present invention,
In the stacking step, a second insulating member may be arranged between the first electrode and the second electrode adjacent in the first direction and at a position overlapping the extension region in the second direction. good.

ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the positive electrode and negative electrode adjacent to a lamination direction short-circuit.

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a perspective view showing a storage element. FIG. 2 is a perspective view showing the inside of the electric storage element of FIG. 1 with the exterior body, the insulating sheet, etc. removed. FIG. 3 is a plan view showing an electrode assembly of the electric storage device of FIG. 1. FIG. 4 is a cross-sectional view showing a cross section taken along line IV-IV of FIG. 3. FIG. FIG. 5 is a cross-sectional view showing a cross section along line V-V of FIG. FIG. 6 is a view corresponding to FIG. 5, and is a cross-sectional view for explaining a specific example of the method for manufacturing the electric storage device. FIG. 7 is a view corresponding to FIG. 5 and a cross-sectional view for explaining a specific example of the method for manufacturing the electric storage device. FIG. 8 is a view corresponding to FIG. 5 and a cross-sectional view for explaining a specific example of the method of manufacturing the electric storage element. FIG. 9 is a plan view corresponding to FIG. 3 and showing a modified example (first modified example) of the storage element. FIG. 10 is a view corresponding to FIG. 4 and a cross-sectional view showing a modified example (second modified example) of the stacked battery. FIG. 11 is a view corresponding to FIG. 5 and a cross-sectional view showing a modified example (second modified example) of the stacked battery. FIG. 12 is a longitudinal cross-sectional perspective view for explaining the laminated structure of the electrode plates of a modification (third modification) of the multilayer battery. FIG. 13 is a view corresponding to FIG. 5 and a cross-sectional view showing a modified example (third modified example) of the stacked battery.

An embodiment of the present invention will be described below with reference to the drawings. In addition, in the drawings attached to this specification, for the convenience of easy understanding, the scale, the ratio of vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the real thing.

In this specification, the terms "plate", "sheet" and "film" are not to be distinguished from each other based only on the difference of names.

In addition, terms such as "parallel", "perpendicular", "identical", length and angle values, etc. that specify shapes and geometric conditions and their degrees used in this specification are strictly It shall be interpreted to include the extent to which similar functions can be expected without being bound by the meaning.

1 to 8 are diagrams for explaining an embodiment of an electric storage device and a method for manufacturing the same according to the present invention.

In one embodiment described below, the electric storage element 1 includes an exterior body 7, an electrode body 5 accommodated in a housing space 7a formed by the exterior body 7, and an exterior body 7 connected to the electrode body 5. and a tab 6 extending from the inside to the outside. Among them, the electrode body 5 includes first electrodes 10 and second electrodes 20 alternately stacked with the first electrodes 10 in the first direction d1. The electrode body 5 includes a plurality of first electrodes 10 and a plurality of second electrodes 20, respectively. In the example shown in FIG. 1, the electric storage device 1 has a flat shape that is thin in a first direction d1 that is the thickness direction as a whole, and has a second direction d2 that is the longitudinal direction and a width direction (the width direction). direction) and a third direction d3. The first direction d1, the second direction d2 and the third direction d3 are non-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.

An example in which the storage element 1 is a stacked battery, specifically a lithium ion secondary battery will be described below. In this example, the first electrode 10 constitutes the positive electrode 10X and the second electrode 20 constitutes the negative electrode 20Y. However, as can be understood from the description of the effects 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 It can be widely applied to the storage device 1 that is alternately laminated in the first direction d1. Moreover, the electric storage element 1 is not limited to a laminated battery, and may be, for example, a wound battery. Even when storage element 1 is a wound battery, first electrode 10 and second electrode 20 are stacked in first direction d1.

Each component of the storage device 1 will be described below.

First, the electrode body 5 will be explained. As shown in FIGS. 2 to 4, the electrode assembly 5 is provided between a positive electrode 10X (first electrode 10), a negative electrode 20Y (second electrode 20), and between the positive electrode 10X and the negative electrode 20Y adjacent in the first direction d1. and an insulating sheet 30 (see FIGS. 3 and 4) disposed. As shown in FIG. 2, the positive electrodes 10X and the negative electrodes 20Y are alternately stacked along the first direction d1. The electrode assembly 5 includes ten or more positive electrodes 10X and ten or more negative electrodes 20Y. 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.

In the non-limiting examples shown in FIGS. 2 and 3, the positive electrode 10X and the negative electrode 20Y are plate-shaped electrodes having a substantially rectangular contour. A second direction d2 non-parallel to the first direction d1 is the longitudinal 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 is the positive electrode 10X and the negative electrode 20Y. 20Y in the lateral direction (width direction). The positive electrode 10X and the negative electrode 20Y are staggered in the second direction d2. More specifically, the plurality of positive electrodes 10X are arranged closer to one side in the second direction d2, and the plurality of negative electrodes 20Y are arranged closer to the other side in the second direction d2. The positive electrode 10X and the negative electrode 20Y overlap in the first direction d1 at the center in the second direction d2.

As shown in FIGS. 2 and 3, the length of the negative electrode 20Y (second electrode 20) along the third direction d3 is longer than the length of the positive electrode 10X (first electrode 10) along the third direction d3. It's becoming In the illustrated example, the negative electrode 20Y extends from the positive electrode 10X to one side and the other side in the third direction d3. 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 longitudinal direction, that is, the length along the second direction d2 is, for example, 200 mm or more and 950 mm or less, The length (width) along the lateral direction, that is, the third direction d3 is, for example, 70 mm or more and 350 mm or less.

As shown in FIG. 4, 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 12X (first electrode current collector 11) provided on the positive electrode current collector 11X. 1 electrode active material layer 12). In the lithium ion secondary battery, the positive electrode 10X releases lithium ions during discharging and absorbs lithium ions during charging.

The positive electrode current collector 11X has, as main surfaces, a first surface 11a and a second surface 11b facing each other. The cathode active material layer 12X is laminated on at least one of the first surface 11a and the second surface 11b of the cathode current collector 11X. Specifically, when the first surface 11a or the second surface 11b of the positive electrode current collector 11X forms the outermost surface of the electrode body 5 in the first direction d1, the surface of the positive electrode current collector 11X has The positive electrode active material layer 12X is not provided. Except for the configuration related to the arrangement of this positive electrode current collector 11X, the plurality of positive electrodes 10X of 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 are identical to each other. can be configured.

The positive electrode current collector 11X and the positive electrode active material layer 12X can be produced by various manufacturing methods using various materials that can be applied to the power storage element 1 (lithium ion secondary battery). As an example, the positive electrode current collector 11X may be made of aluminum foil. The positive electrode active material layer 12X contains, for example, a positive electrode active material, a conductive aid, and a binding agent that serves as a binder. The positive electrode active material layer 12X is produced by applying a positive electrode slurry obtained by dispersing a positive electrode active material, a conductive aid, and a binder in a solvent onto the material forming the positive electrode current collector 11X and solidifying the slurry. can be As the positive electrode active material, for example, a lithium metal oxide compound represented by the 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, and lithium manganate. Acetylene black or the like may be used as the conductive aid. Polyvinylidene fluoride or the like may be used as the binder.

As shown in FIGS. 2 to 4, the positive electrode current collector 11X (first electrode current collector 11) has a first end region a1 (connection region) and a first electrode region b1 (effective region). there is As shown in FIG. 4, the positive electrode active material layer 12X (first electrode active material layer 12) is laminated only on 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 adjacent to each other along the second direction d2. The first end region a1 is located on one side in the second direction d2 of the first electrode region b1. The plurality of positive electrode current collectors 11X are joined to one tab 6 in the first end region a1 by resistance welding, ultrasonic welding, tape attachment, fusion bonding, or the like. In the illustrated example, the first end regions a1 of the plurality of positive electrodes 10X are overlaid on the tab 6 and electrically connected to each other. On the other hand, the first electrode region b1 extends within a region of the negative electrode 20Y facing a negative electrode active material layer 22Y described later. Such arrangement of the first electrode region b1 can prevent deposition of lithium from the positive electrode active material layer 12X.

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 have In the lithium ion secondary battery, the negative electrode 20Y absorbs lithium ions during discharging and releases lithium ions during charging.

The negative electrode current collector 21Y has, as main surfaces, a first surface 21a and a second surface 21b facing each other. The negative electrode active material layer 22Y is laminated on at least one of the first surface 21a and the second surface 21b of the negative electrode current collector 21Y. The plurality of negative electrodes 20Y of 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 can be configured identically to each other.

The negative electrode current collector 21Y and the negative electrode active material layer 22Y can be produced by various manufacturing methods using various materials that can be applied to the power storage element 1 (lithium ion secondary battery). As an example, the negative electrode current collector 21Y is made of copper foil, for example. The negative electrode active material layer 22Y contains, for example, a negative electrode active material made of a carbon material and a binder that functions as a binder. The negative electrode active material layer 22Y is formed by dispersing a negative electrode slurry in which a negative electrode active material such as carbon powder or graphite powder and a binder such as polyvinylidene fluoride are dispersed in a solvent to form the negative electrode collector 21Y. It can be made by coating on a material and solidifying it.

As shown in FIGS. 2 to 4, the negative electrode current collector 21Y (second electrode current collector 21) has a second end region a2 (connection region) and a second electrode region b2 (effective region). there is As shown in FIG. 4, the negative electrode active material layer 22Y (second electrode active material layer 22) is laminated only on the second electrode region b2 of the negative electrode current collector 21Y. The second end region a2 and the second electrode region b2 are arranged adjacent to each other along the second direction d2. The second end region a2 is located on the other side in the second direction d2 of the second electrode region b2. A plurality of negative electrode current collectors 21Y are joined to one tab 6 in the second end region a2 by resistance welding, ultrasonic welding, sticking with a tape, fusion bonding, or the like. In the illustrated example, the second end regions a2 of the plurality of negative electrodes 20Y are overlapped on a tab 6 different from the tab 6 to which the positive electrode current collector 11X is joined, and are electrically connected to each other. . On the other hand, the second electrode region b2 extends over a region of the positive electrode 10X facing the positive electrode active material layer 12X.

As described above, the first electrode region b1 of the positive electrode 10X is positioned inside the region facing the second electrode region b2 of the negative electrode 20Y (see FIG. 4). That is, the second electrode region b2 extends over a region that includes the region facing the positive electrode active material layer 12X of the positive electrode 10X.

Therefore, as shown in FIGS. 3 and 4, the negative electrode active material layer 22Y (the second electrode active material layer 22) is the same as the positive electrode active material layer 12X (the first electrode active material layer 12) in the second direction d2. It has an extension region 25 extending outside (one side or the other side in the second direction d2) of the end portion 12a. In this case, as shown in FIG. 3, the length L1 of the extension region 25 along the second direction d2 may be 0.5 mm or more and 4.0 mm or less. Since the length L1 of the extension region 25 along the second direction d2 is 0.5 mm or more, the region for forming the joint portion 31 is sufficiently formed at the position overlapping the extension region 25 in the second direction d2. can be secured to Further, by setting the length L1 of the extension region 25 along the second direction d2 to 4.0 mm or less, the ratio of the region where the positive electrode active material layer 12X spreads to the region where the negative electrode active material layer 22Y spreads can be increased. , and the volumetric energy density of the storage element 1 can be increased. Here, the volumetric energy density means the amount of power that can be supplied by the storage element 1 per volume occupied by the storage element 1 .

Next, the insulating sheet 30 will be explained. As shown in FIGS. 4 and 5, the insulating sheet 30 is positioned between the positive electrode 10X (first electrode 10) and the negative electrode 20Y (second electrode 20), and prevents the positive electrode 10X and the negative electrode 20Y from coming into contact with each other. 10X and negative electrode 20Y are spaced apart from each other. In this embodiment, the storage device 1 includes a plurality of insulating sheets 30 . The insulating sheet 30 has insulating properties and prevents a short circuit due to contact between the positive electrode 10X and the negative electrode 20Y.

The insulating sheet 30 is preferably made of a resin composition containing at least one of polypropylene and polyethylene. As a result, the insulating sheets 30 can be easily welded together by the joints 31, and the joint strength at the joints 31 can be improved.

Moreover, the insulating sheet 30 preferably has a high ion permeability (air permeability), a predetermined mechanical strength, and durability against the electrolytic solution, the positive electrode active material, the negative electrode active material, and the like. As such an insulating sheet 30, for example, a porous body or a non-woven fabric made 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 insulating sheet 30 . Polyolefin polymers such as polypropylene and polyethylene can be used as the thermoplastic resin. The housing space 7 a of the exterior body 7 is filled with an electrolytic solution together with the electrode body 5 . By impregnating the insulating sheet 30 made of a porous material or a non-woven fabric with the electrolytic solution, the electrode active material layers 12 and 22 of the electrodes 10 and 20 are kept in contact with the electrolytic solution.

Alternatively, the insulating sheet 30 may be formed by solidifying or gelling an electrolytic solution coated on the active material layers 22Y and 12X on the active material layers 22Y and 12X. The electrolytic solution, for example, consists of a polymer matrix and a non-aqueous electrolytic solution (that is, a non-aqueous solvent and an electrolyte salt), and is gelled to produce stickiness on the surface, or consists of a polymer matrix and a non-aqueous solvent. , a solid electrolyte can be used. In this case, the specific material for producing the insulating sheet 30 is not particularly limited, and various materials used for composing them (for example, materials disclosed in Japanese Patent Application Laid-Open No. 2012-190567 ) can be used.

The insulating sheet 30 is positioned, for example, between any two electrodes 10 and 20 adjacent in the first direction d1. Further, the insulating sheet 30 spreads so as to cover the entire area of the positive electrode active material layer 12X of the positive electrode 10X in plan view (see FIG. 3). Similarly, the insulating sheet 30 extends so as to cover the entire area of the negative electrode active material layer 22Y of the negative electrode 20Y in plan view. Therefore, the insulating sheet 30 covers the extension region 25 of the negative electrode active material layer 22Y of the negative electrode 20Y. Furthermore, as shown in FIGS. 3 and 5, the insulating sheet 30 has a width along the third direction d3 that is wider than the widths of the positive electrode 10X and the negative electrode 20Y along the third direction d3. To clarify the drawing, FIG. 5 omits illustration of the positive electrode current collector 11X, the positive electrode active material layer 12X, the negative electrode current collector 21Y, and the negative electrode active material layer 22Y.

Insulating sheets 30 adjacent in the first direction d1 are joined to each other via joints 31 . In this embodiment, the respective insulating sheets 30 are joined to each other at the joining portion 31 . In this case, the plurality of insulating sheets 30 are bonded to each other by, for example, crimping using ultrasonic vibration or the like. Further, as shown in FIG. 3, at least part of the joint 31 is formed at a position overlapping the extension region 25 of the negative electrode active material layer 22Y (second electrode active material layer 22) in the second direction d2. . Accordingly, it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 . In particular, since at least a part of the joint portion 31 is formed at a position overlapping the extension region 25 in the second direction d2, the extension region 25 does not move even when vibration or the like is applied to the storage element 1, for example. , it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y. Therefore, it is possible to prevent the negative electrode active material layer 22</b>Y covered with the insulating sheet 30 from being exposed from the insulating sheet 30 in the extended region 25 . As a result, it is possible to prevent the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1 from coming into contact with each other and causing a short circuit between the positive electrode 10X and the negative electrode 20Y.

Also, as shown in FIGS. 3 and 5, the joints 31 are formed on both sides of the negative electrode 20Y in the third direction d3. Thereby, it is possible to more effectively prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 .

Further, as shown in FIG. 3, in the present embodiment, the joint portion 31 is formed to have a substantially rectangular outer contour in plan view. The length L2 along the second direction d2 of the portion of the joint portion 31 that overlaps the extension region 25 in the second direction d2 may be 0.5 mm or more and 4.0 mm or less. When the length L2 is 0.5 mm or more, the insulating sheets 30 can be firmly joined to each other at positions overlapping the extension regions 25 in the second direction d2. Therefore, it is possible to more effectively prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 . Further, since the length L2 is 4.0 mm or less, it is possible to suppress the shrinkage of the insulating sheet 30 in the extension region 25 when the insulating sheet 30 is joined, and The occurrence of distortion in 30 can be suppressed. Therefore, it is possible to prevent the negative electrode active material layer 22</b>Y covered with the insulating sheet 30 from being exposed from the insulating sheet 30 in the extended region 25 . Note that the shape of the joint portion 31 is arbitrary, and the joint portion 31 may have a circular shape or an elliptical shape in plan view.

A length L3 of the joint portion 31 along the second direction d2 may be 0.5 mm or more and 4.0 mm or less. Since the length L3 of the joint portion 31 along the second direction d2 is 0.5 mm or more, the joint strength between the insulating sheets 30 at the joint portion 31 can be increased, and the insulating sheet 30 is the negative electrode active material layer. It is possible to more effectively suppress movement with respect to 22Y. In addition, since the length L3 of the joint portion 31 along the second direction d2 is 4.0 mm or less, when the insulating sheet 30 is joined, it is possible to suppress the contraction of the insulating sheet 30, thereby preventing the insulating sheet 30 from shrinking. It is possible to suppress the occurrence of distortion in the seat 30 .

Next, tab 6 will be described. Tab 6 functions as a terminal in storage element 1 . As shown in FIGS. 2 to 4, one tab 6 (the tab 6 positioned on one side in the second direction d2) is electrically connected to the positive electrode 10X of the electrode assembly 5. As shown in FIGS. Similarly, the other tab 6 (the tab 6 located on the other side in the second direction d2) is electrically connected to the negative electrode 20Y of the electrode body 5. As shown in FIG. As shown in FIG. 4 , the pair of tabs 6 extends out of the exterior body 7 from a housing space 7 a inside the exterior body 7 . The length of the tab 6 extending outside the exterior body 7 is, for example, 10 mm or more and 25 mm or less. The space between the exterior body 7 and the tab 6 is sealed via a sealing member (not shown) in the region where the tab 6 extends.

Tab 6 may be formed using aluminum, copper, nickel, nickel-plated copper, or the like. The thickness of the tab 6 is, for example, 0.1 mm or more and 1 mm or less.

Next, the exterior body 7 will be described. The exterior body 7 is a packaging material for sealing the electrode body 5 . As shown in FIGS. 4 and 5 , the exterior body 7 has a first exterior material 71 and a second exterior material 72 . Each of the exterior materials 71 and 72 has metal layers 71a and 72a and sealant layers 71b and 72b laminated on the metal layers 71a and 72a, respectively. The metal layers 71a and 72a preferably have high gas barrier properties and moldability.

The material forming the metal layers 71a and 72a is not particularly limited as long as it prevents moisture from entering from the outside and improves the strength of the electric storage element 1. However, from the viewpoint of water barrier properties, weight and cost, known metals can be used. , metal oxides, metal nitrides, and alloys thereof can be used, and aluminum, aluminum alloys, stainless steel, etc. are preferable, and aluminum can be particularly preferably used. Instead of the metal foil, a metal layer may be provided by vapor deposition, sputtering, or the like, as long as the strength of the entire power storage device 1 can be secured.

The sealant layers 71b and 72b have insulating properties and prevent a short circuit between the electrode body 5 accommodated in the exterior body 7 and the metal layers 71a and 72a. Moreover, the sealant layers 71b and 72b have thermoplasticity (adhesiveness) in addition to insulation. The first exterior material 71 and the second exterior material 72 are laminated such that the sealant layers 71b and 72b face each other, and their peripheries are welded to each other. Furthermore, a housing space 7 a for the electrode body 5 is formed between the first exterior member 71 and the second exterior member 72 .

The exterior body 7 hermetically seals the electrode body 5 and the electrolytic solution therein. Since the sealant layers 71b and 72b are also in contact with the electrolytic solution, it is preferable that the sealant layers 71b and 72b have chemical resistance. Polyolefin-based resins such as polypropylene, modified polypropylene, low-density polypropylene, ionomer, and ethylene-vinyl acetate can be used as materials for the sealant layers 71b and 72b.

In the illustrated example, the first exterior material 71 is formed as a plate-like member. On the other hand, the second exterior member 72 is formed in a cup shape. The second exterior member 72 has a cup-shaped swelling portion 73 and a collar portion 74 connected to the swelling portion 73 . The flange portion 74 surrounds the bulging portion 73 in a circumferential shape and is connected to the peripheral edge of the bulging portion 73 . The collar portion 74 is adhered to the first exterior material 71 so as to seal the accommodation space 7a between the first exterior material 71 and the second exterior material 72 . The bulging portion 73 is manufactured by drawing, for example.

However, it is not limited to the above example, and the exterior body 7 may be formed by folding back one sheet of exterior material. In this example, the exterior body 7 has a bonding area formed by bonding exterior materials facing each other in the edge portion other than the folded portion.

Next, an example of a method for manufacturing the storage device 1 of the present embodiment will be described.

First, the positive electrode 10X, the negative electrode 20Y and the insulating sheet 30 are produced. The positive electrode 10X, the negative electrode 20Y, and the insulating sheet 30 can be produced using the materials and manufacturing methods described above. Next, as shown in FIG. 6, the fabricated positive electrode 10X, negative electrode 20Y, and insulating sheet 30 are placed between the positive electrode 10X and the negative electrode 20Y that are adjacent to each other in the first direction d1. Laminate as follows. In this case, each of the plurality of insulating sheets 30 is laminated so as to be arranged between the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1. The insulating sheet 30 covers the extended region 25 of the negative electrode active material layer 22Y.

Next, the insulating sheets 30 adjacent to each other in the first direction d1 are joined together via the joining portion 31 . In this case, each insulating sheet 30 is joined together. At this time, first, as shown in FIG. 7, a plurality of insulating sheets 30 are overlapped on both sides of the negative electrode 20Y in the third direction d3. Next, the plurality of overlapping insulating sheets 30 are crimped to each other using, for example, ultrasonic vibration. Thus, as shown in FIG. 8, the joints 31 are formed on both sides of the negative electrode 20Y in the third direction d3. Also, at this time, at least part of the joint portion 31 is formed at a position overlapping the extension region 25 in the second direction d2. In this case, the length L2 along the second direction d2 (see FIG. 3) of the portion of the joint 31 that overlaps the extension region 25 in the second direction d2 is 0.5 mm or more and 4.0 mm or less. good too. Thus, the electrode body 5 is obtained.

Next, the positive electrode current collectors 11X of the plurality of positive electrodes 10X are electrically connected to each other, and the tabs 6 are also electrically connected. Similarly, the negative electrode current collectors 21Y of the plurality of negative electrodes 20Y are electrically connected to each other, and the tabs 6 are also electrically connected.

Also, the first exterior material 71 and the second exterior material 72 that constitute the exterior body 7 are prepared. A bulging portion 73 is formed in the second exterior member 72 by drawing, for example. Next, the electrode body 5 is accommodated in the bulging portion 73 of the second packaging material 72 , and the first packaging material 71 is laminated on the second packaging material 72 . At this time, the sealant layer 72b of the second exterior material 72 and the sealant layer 71b of the first exterior material 71 face each other. Also, each tab 6 extends from between the first exterior member 71 and the second exterior member 72 .

After that, the first exterior material 71 and the flange portion 74 of the second exterior material 72 are joined. The first exterior material 71 and the second exterior material 72 are joined by welding, for example, by heating and pressurizing the first exterior material 71 and the second exterior material 72 . This heating and pressurization is carried out by heating the first exterior material 71 and the second exterior material 72 to 120° C. or more and 200° C. or less and pressurizing them to 0.2 MPa or more and 0.8 MPa or less for 1 second or more. It is done by maintaining for seconds or less.

Through the above steps, the storage device 1 as shown in FIG. 1 is manufactured.

As described above, in the energy storage device 1 of the present embodiment, the positive electrode 10X, the negative electrode 20Y alternately stacked with the positive electrode 10X in the first direction d1, and the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1 The negative electrode active material layer 22Y of the negative electrode 20Y has an extension region 25 extending outside the end portion 12a of the positive electrode active material layer 12X in the second direction d2. The insulating sheet 30 covers the extended region 25 of the negative electrode active material layer 22Y, and the insulating sheets 30 adjacent in the first direction d1 are joined to each other via the joints 31. At least part of it is formed at a position overlapping the extension region 25 of the negative electrode active material layer 22Y in the second direction d2. Accordingly, it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 . In particular, since at least a part of the joint portion 31 is formed at a position overlapping the extension region 25 in the second direction d2, the extension region 25 does not move even when vibration or the like is applied to the storage element 1, for example. , it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y. Therefore, it is possible to prevent the negative electrode active material layer 22</b>Y covered with the insulating sheet 30 from being exposed from the insulating sheet 30 in the extended region 25 . As a result, it is possible to prevent the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1 from coming into contact with each other and causing a short circuit between the positive electrode 10X and the negative electrode 20Y. Furthermore, in the energy storage device 1 of the present embodiment, at least a portion of the junction 31 is formed at a position overlapping the extension region 25 of the negative electrode active material layer 22Y in the second direction d2. : 2007, can show excellent performance in the crush test.

Further, according to the present embodiment, the joints 31 are formed on both sides of the negative electrode 20Y in the third direction d3. Thereby, it is possible to more effectively prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y. Therefore, the negative electrode active material layer 22Y covered with the insulating sheet 30 can be prevented from being exposed from the insulating sheet 30 in the extension region 25, and the positive electrode 10X and the negative electrode 20Y are short-circuited. Defects can be suppressed more effectively.

Furthermore, according to the present embodiment, insulating sheet 30 is made of a resin composition containing at least one of polypropylene and polyethylene. As a result, the insulating sheets 30 can be easily welded together by the joints 31, and the joint strength at the joints 31 can be improved. As a result, it is possible to more effectively prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y, and the negative electrode active material layer 22Y covered with the insulating sheet 30 is , exposure from the insulating sheet 30 can be suppressed. As a result, it is possible to more effectively suppress the short circuit between the positive electrode 10X and the negative electrode 20Y.

Although one embodiment has been described above with reference to specific examples, the above-described specific examples are not intended to limit one embodiment. The embodiment described above can be implemented in various other specific examples, and various omissions, replacements, and modifications can be made without departing from the spirit of the embodiment.

An example of modification will be described below with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described specific example are used for the portions that can be configured in the same manner as in the above-described specific example, and redundant description is given. omitted.

(First modification)
In the above description, a case where a part of the joint portion 31 is formed at a position overlapping the extension region 25 of the negative electrode active material layer 22Y in the second direction d2 has been described as an example, but the present invention is not limited to this. For example, as shown in FIG. 9, the entire joint portion 31 may overlap the extension region 25 in the second direction d2. Also in this modification, it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 . Therefore, the negative electrode active material layer 22Y covered with the insulating sheet 30 can be prevented from being exposed from the insulating sheet 30 in the extension region 25, and the positive electrode 10X and the negative electrode 20Y are short-circuited. Defects can be suppressed.

(Second modification)
Moreover, although one specific example of the storage element 1 has been described above, the storage element 1 is not limited to the specific examples shown in FIGS. 1 to 8 . For example, as shown in FIGS. 10 and 11, in the electric storage element 1, the first insulating member is provided in the first end region a1 of the positive electrode current collector 11X at a position overlapping the extension region 25 in the second direction d2. 13 may be provided. Further, in the storage element 1, even if the second insulating member 23 is provided between the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1 and at a position overlapping the extension region 25 in the second direction d2. good. In this case, the second insulating member 23 may be provided on the insulating sheet 30 . The first insulating member 13 and the second insulating member 23 may each consist of a layer containing metal oxide or a tape containing metal oxide. In this case, the metal oxide may be alumina, titania, zirconia, magnesia, or the like. In addition, when the first insulating member 13 and the second insulating member 23 are each made of a layer containing a metal oxide, the first insulating member 13 and the second insulating member 23 each contain a binder that serves as a binder. good too. In this case, as a binding agent that serves as a binder, for example, polyvinylidene fluoride resin (PVDF), styrene-butadiene rubber (SBR), acryl, or the like may be used. For the first insulating member 13 and the second insulating member 23, a slurry obtained by dispersing a metal oxide and a binder in a solvent is coated on the materials forming the positive electrode current collector 11X and the insulating sheet 30, respectively, and solidified. It can be made by

The first insulating member 13 preferably extends so as to cover the entire region of the positive electrode current collector 11X that overlaps the extension region 25 in the second direction d2. Accordingly, it is possible to more effectively prevent the positive electrode current collector 11X covered with the first insulating member 13 from being exposed from the first insulating member 13 in the extension region 25 . Moreover, it is preferable that the second insulating member 23 spread so as to cover the entire region of the negative electrode active material layer 22Y of the negative electrode 20Y in plan view. Accordingly, it is possible to more effectively prevent the negative electrode active material layer 22Y covered with the second insulating member 23 from being exposed from the second insulating member 23 in the extension region 25 .

When manufacturing the power storage element 1 shown in FIGS. 10 and 11, first, when fabricating the positive electrode 10X, a portion of the positive electrode current collector 11X of the positive electrode 10X, which is located in the first end region a1, is first 1 An insulating member 13 is provided. Also, when the insulating sheet 30 is manufactured, the insulating sheet 30 is provided with the second insulating member 23 . In this case, when the first insulating member 13 and the second insulating member 23 are each made of a layer containing a metal oxide and a binder, for example, alumina, titania, zirconia, magnesia, etc. are contained as the metal oxide, and PVDF is used as the binder. The first insulating member 13 and the second insulating member 23 may be formed on the positive electrode current collector 11X and the insulating sheet 30, respectively, by a layer containing SBR, acrylic, or the like. On the other hand, when the first insulating member 13 and the second insulating member 23 are each made of a tape containing a metal oxide, the first insulating member 13 and the second insulating member 23 are attached to the positive electrode current collector 11X and the insulating sheet 30, respectively. You may wear

Next, the positive electrode 10X, the negative electrode 20Y and the insulating sheet 30 are laminated. In this case, the first insulating member 13 is arranged at a position overlapping the extension region 25 in the second direction d2 in the positive electrode current collector 11X. A second insulating member 23 is arranged between the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1 and at a position overlapping the extension region 25 in the second direction d2. Thus, the positive electrode 10X, the negative electrode 20Y and the insulating sheet 30 are laminated.

Next, as described with reference to FIGS. 7 and 8, the insulating sheets 30 adjacent to each other in the first direction d1 are joined via the joining portion 31. As shown in FIG.

Next, the positive electrode current collectors 11X of the plurality of positive electrodes 10X are electrically connected to each other, and the tabs 6 are also electrically connected. Similarly, the negative electrode current collectors 21Y of the plurality of negative electrodes 20Y are electrically connected to each other, and the tabs 6 are also electrically connected.

After that, the first exterior material 71 and the flange portion 74 of the second exterior material 72 are joined.

Through the steps described above, the storage element 1 as shown in FIGS. 10 and 11 is manufactured.

According to this modification, the first insulating member 13 is provided at a position overlapping the extension region 25 in the second direction d2 in the first end region a1 of the positive electrode current collector 11X. As a result, the positive electrode 10X covered with the first insulating member 13 can be prevented from being exposed in the extension region 25 even when the power storage element 1 is subjected to vibration or the like. Therefore, it is possible to more effectively suppress the short circuit due to contact between the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1. A second insulating member 23 is provided between the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1 and at a position overlapping the extension region 25 in the second direction d2. This prevents the negative electrode active material layer 22Y covered with the second insulating member 23 from being exposed in the extension region 25 even when vibration or the like is applied to the storage element 1, for example. can be done. Therefore, it is possible to more effectively suppress the short circuit due to contact between the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1.

Moreover, according to this modification, the first insulating member 13 and the second insulating member 23 are each made of a layer containing a metal oxide or a tape. As a result, when the energy storage element 1 is in a high temperature state of about 80° C., for example, even if the energy storage element 1 is subjected to vibration or the like, the positive electrode 10X and the second electrode 10X covered with the first insulating member 13 can be It is possible to prevent the negative electrode active material layer 22</b>Y covered with the insulating member 23 from being exposed in the extension region 25 . Therefore, it is possible to more effectively suppress the short circuit due to contact between the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1.

(Third modification)
Further, for example, as shown in FIGS. 12 and 13, in the electric storage element 1, the insulating sheets 30 may be alternately folded back in the third direction d3. As shown in FIG. 12, the insulating sheet 30 is alternately folded back in the third direction d3 (width direction). That is, the insulating sheet 30 has a zigzag shape. In this case, one of the pair of main surfaces facing each other of the insulating sheet 30 faces the positive electrode 10X, and the other of the pair of main surfaces faces the negative electrode 20Y. Become. As shown in FIG. 13 , in this modified example, portions of the insulating sheet 30 that are adjacent in the first direction d1 are joined together at the joining portion 31 .

In the illustrated example, one insulating sheet 30 is arranged in a zigzag shape between the positive electrode 10X and the negative electrode 20Y. However, without being limited to this example, the electric storage element 1 may have a plurality of insulating sheets 30 in a zigzag shape.

12 and 13, when the positive electrode 10X, the negative electrode 20Y and the insulating sheet 30 are laminated, the insulating sheet 30 is alternately folded in the third direction d3. In this manner, the insulating sheet 30 is laminated so as to be disposed between the positive electrode 10X and the negative electrode 20Y adjacent to each other in the first direction d1, and the insulating sheet 30 covers the extension region 25 of the negative electrode active material layer 22Y. .

Next, as described with reference to FIGS. 7 and 8, the insulating sheets 30 adjacent to each other in the first direction d1 are joined via the joining portion 31. As shown in FIG. In this case, adjacent portions of the insulating sheet 30 in the first direction d1 are joined together.

Next, the positive electrode current collectors 11X of the plurality of positive electrodes 10X are electrically connected to each other, and the tabs 6 are also electrically connected. Similarly, the negative electrode current collectors 21Y of the plurality of negative electrodes 20Y are electrically connected to each other, and the tabs 6 are also electrically connected.

After that, the first exterior material 71 and the flange portion 74 of the second exterior material 72 are joined.

Through the steps described above, the storage element 1 as shown in FIG. 13 is manufactured.

Also in this modification, it is possible to prevent the insulating sheet 30 from moving with respect to the negative electrode active material layer 22Y in the extension region 25 . Therefore, it is possible to prevent the negative electrode active material layer 22</b>Y covered with the insulating sheet 30 from being exposed from the insulating sheet 30 in the extended region 25 . As a result, it is possible to prevent the negative electrode 20Y and the positive electrode 10X arranged along the first direction d1 from coming into contact with each other and causing a short circuit between the positive electrode 10X and the negative electrode 20Y.

Aspects of the present invention are not limited to the above-described embodiments, but include various modifications that can be conceived by those skilled in the art, and effects of the present invention are not limited to the above-described contents. That is, various additions, changes, and partial deletions are possible without departing from the conceptual idea and spirit of the present invention derived from the content defined in the claims and equivalents thereof.

Although several modifications of the above-described embodiment have been described above, it is of course possible to apply a plurality of modifications in appropriate combination.

1 storage element 10 first electrode 10X positive electrode 11 first electrode current collector 11X positive electrode current collector 12 first electrode active material layer 12a end portion 12X positive electrode active material layer 13 first insulating member 20 second electrode 20Y negative electrode 21 second second Electrode current collector 21Y Negative electrode current collector 22 Second electrode active material layer 22Y Negative electrode active material layer 23 Second insulating member 25 Extension region 30 Insulating sheet 31 Joint portion a1 First end region a2 Second end region b1 1st electrode region b2 2nd electrode region

Claims (21)

a first electrode;
a second electrode alternately stacked with the first electrode in a first direction;
an insulating sheet disposed between the first electrode and the second electrode adjacent in the first direction;
The first electrode includes a first electrode current collector including an effective region and a connection region adjacent to the effective region, and a first electrode active material layer laminated on the effective region of the first electrode current collector. , has
The second electrode includes a second electrode current collector including an effective region and a connection region adjacent to the effective region, and a second electrode active material layer laminated on the effective region of the second electrode current collector. , has
the second electrode active material layer has an extension region extending outward from an end portion of the first electrode active material layer in a second direction non-parallel to the first direction;
The insulating sheet covers the extension region of the second electrode active material layer,
The insulating sheets that are adjacent in the first direction are joined to each other via joints,
At least part of the joint is formed at a position overlapping the extension region of the second electrode active material layer in the second direction ,
The power storage element , wherein the joint portion has a length of 0.5 mm or more and 4.0 mm or less along the second direction . a first electrode;
a second electrode alternately stacked with the first electrode in a first direction;
an insulating sheet disposed between the first electrode and the second electrode adjacent in the first direction;
The first electrode includes a first electrode current collector including an effective region and a connection region adjacent to the effective region, and a first electrode active material layer laminated on the effective region of the first electrode current collector. , has
The second electrode includes a second electrode current collector including an effective region and a connection region adjacent to the effective region, and a second electrode active material layer laminated on the effective region of the second electrode current collector. , has
the second electrode active material layer has an extension region extending outward from an end portion of the first electrode active material layer in a second direction non-parallel to the first direction;
The insulating sheet covers the extension region of the second electrode active material layer,
The insulating sheets that are adjacent in the first direction are joined to each other via joints,
At least part of the joint is formed at a position overlapping the extension region of the second electrode active material layer in the second direction,
The electric storage element, wherein the entire joint portion overlaps the extension region in the second direction. 3. The electric storage device according to claim 2, wherein the joint portion has a length of 0.5 mm or more and 4.0 mm or less along the second direction. A plurality of the insulating sheets,
The electric storage element according to any one of claims 1 to 3 , wherein the respective insulating sheets are joined to each other at the joining portion. The insulating sheets are alternately folded in a third direction non-parallel to both the first direction and the second direction,
The electric storage element according to any one of claims 1 to 4 , wherein in the joint portion, portions of the insulating sheet that are adjacent in the first direction are joined to each other. The electric storage element according to any one of claims 1 to 5 , comprising a plurality of said first electrodes and said second electrodes. 7. The length along the second direction of the portion of the joint that overlaps the extension region in the second direction is 0.5 mm or more and 4.0 mm or less. The storage device according to the above item. The power storage according to any one of claims 1 to 7 , wherein the joints are formed on both sides of the second electrode in a third direction non-parallel to both the first direction and the second direction. element. The power storage device according to any one of claims 1 to 8 , wherein the extension region has a length along the second direction of 0.5 mm or more and 4.0 mm or less. The electric storage element according to any one of claims 1 to 9 , wherein the insulating sheet is made of a resin composition containing at least one of polypropylene and polyethylene. 11. The first insulating member according to any one of claims 1 to 10, wherein a first insulating member is provided at a position overlapping said extension region in said second direction in said connection region of said first electrode current collector. storage element. 12. The electric storage device according to claim 11, wherein said first insulating member is made of a layer or tape containing a metal oxide. 2. A second insulating member is provided between the first electrode and the second electrode adjacent to each other in the first direction and at a position overlapping the extension region in the second direction. 13. The electricity storage device according to any one of items 12 to 13. 14. The electric storage element according to claim 13, wherein the second insulating member is made of a layer or tape containing a metal oxide. The electric storage element according to any one of claims 1 to 14, comprising ten or more of each of said first electrodes and said second electrodes. a first electrode having a first electrode current collector including an effective region and a connection region adjacent to the effective region; a second electrode having a second electrode current collector including a region and a connection region adjacent to the effective region; and a second electrode active material layer laminated on the effective region of the second electrode current collector; and an insulating sheet. a lamination step of laminating the insulating sheet so that it is arranged between the first electrode and the second electrode adjacent in the first direction;
a bonding step of bonding the insulating sheets adjacent to each other in the first direction via a bonding portion;
the second electrode active material layer has an extension region extending outward from an end portion of the first electrode active material layer in a second direction non-parallel to the first direction;
In the lamination step, the extended region of the second electrode active material layer is covered with the insulating sheet;
In the bonding step, at least part of the bonding portion is formed at a position overlapping the extension region of the second electrode active material layer in the second direction;
The method for manufacturing an electric storage element , wherein the joint portion has a length along the second direction of 0.5 mm or more and 4.0 mm or less . In the lamination step, a plurality of the insulating sheets are laminated,
17. The method of manufacturing an electric storage element according to claim 16, wherein in said joining step, said insulating sheets are joined to each other. In the lamination step, the insulating sheets are alternately folded in a third direction that is non-parallel to both the first direction and the second direction;
18. The method of manufacturing a power storage element according to claim 16, wherein in said bonding step, adjacent portions of said insulating sheets in said first direction are bonded to each other. 19. The method according to any one of claims 16 to 18, wherein in the bonding step, the bonding portions are formed on both sides of the extension region in a third direction non-parallel to both the first direction and the second direction. and a method for manufacturing an electric storage element. 20. The method according to any one of claims 16 to 19, wherein in the lamination step, a first insulating member is arranged at a position of the first electrode current collector that overlaps the extension region in the second direction. A method for manufacturing an electric storage element. In the stacking step, a second insulating member is arranged between the first electrode and the second electrode adjacent in the first direction and at a position overlapping the extension region in the second direction. Item 21. A method for manufacturing an electric storage device according to any one of Items 16 to 20.

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