Electricity storage device and method for manufacturing the same

Abstract

To provide a power storage device capable of suppressing uneven distribution of pressure applied to an adjacent power storage device when a plurality of power storage devices are stacked, and a manufacturing method of the power storage device.SOLUTION: A power storage device 10 includes an electrode body and an exterior body 100. The exterior body seals an electrode body. The exterior body is composed of a film-shaped exterior member. The exterior body includes a first sealing portion 110 that is sealed by joining surfaces facing each other while being wound around the electrode body. A base portion of the first sealing portion is formed at the boundary between a first surface 130 and a second surface 140 in the exterior body. The area of the first surface is larger than the area of the second surface. The first sealing portion does not overlap the first surface in a plan view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electricity storage device and a method for manufacturing an electricity storage device. [Background technology]

[0002] Japanese Patent No. 4509242 (Patent Document 1) discloses a secondary battery in which an electrode body is sealed in a pouch made of a laminate film (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4509242 Summary of the Invention [Problem to be solved by the invention]

[0004] In the secondary battery disclosed in the above Patent Document 1, a seal part of a laminate film is provided on a surface having a large area. The seal part is a region where the films overlap, and is therefore thicker than other regions. When other secondary batteries are stacked on the surface on which the seal part is provided, the upper secondary battery may tilt with the seal part as a fulcrum. As a result, the unevenness of the distribution of pressure applied to the lower secondary battery increases. In addition, when multiple secondary batteries are arranged horizontally so that the surface on which the seal part is provided is in contact with the adjacent secondary battery, the unevenness of the distribution of pressure applied from the adjacent secondary battery also increases.

[0005] The present invention has been made to solve such problems, and its object is to provide an electricity storage device and a manufacturing method for such an electricity storage device that can suppress unevenness in the distribution of pressure applied to adjacent electricity storage devices when multiple electricity storage devices are stacked. [Means for solving the problem]

[0006] An electricity storage device according to an aspect of the present invention includes an electrode body and an exterior body. The exterior body seals the electrode body. The exterior body is composed of a film-like exterior member. The exterior body includes a first sealing portion sealed by joining surfaces that face each other when the exterior member is wrapped around the electrode body. A root portion of the first sealing portion is formed at the boundary between the first surface and the second surface of the exterior body. The area of ​​the first surface is larger than the area of ​​the second surface. The first sealing portion does not overlap the first surface in a plan view.

[0007] In this electricity storage device, the first sealing portion does not overlap with the first surface having a large area in a plan view. That is, the first sealing portion does not exist on the first surface having a large area. Therefore, even if another electricity storage device is arranged on the first surface side by side or above, the other electricity storage device does not tilt. As a result, this electricity storage device can suppress unevenness in the distribution of pressure applied to adjacent electricity storage devices when multiple electricity storage devices are stacked. Also, in this electricity storage device, the root portion of the first sealing portion is on the boundary between the first surface and the second surface of the exterior body. Therefore, according to this electricity storage device, when the first sealing portion is placed on the second surface, a wider joint width can be secured in the first sealing portion compared to when the root portion of the first sealing portion is on the second surface.

[0008] In the electricity storage device, the first sealing portion may be bent so as to be in contact with the second surface.

[0009] In the above electricity storage device, the first sealing portion may cover substantially the entire second surface when folded so as to be in contact with the second surface.

[0010] In this electricity storage device, the first sealing portion covers substantially the entire second surface, so that a wide bonding width can be ensured in the first sealing portion.

[0011] The power storage device further includes an electrode terminal electrically connected to the electrode body, and the outer casing further includes a second sealing portion sealed while sandwiching the electrode terminal, a portion of the electrode terminal is located outside the outer casing, and a root portion of the portion may be located at a position approximately halfway through the thickness of the power storage device in the thickness direction of the power storage device.

[0012] In this electricity storage device, a portion of the electrode terminal that is outside the exterior body is located at a position that is approximately halfway through the thickness of the electricity storage device in the thickness direction of the electricity storage device. Therefore, with this electricity storage device, it is possible to reduce the difference between the longest distance and the shortest distance between each of the multiple electrodes included in the electrode body and the electrode terminal, compared to a case in which the portion is located at approximately the same position as the first surface in the thickness direction of the electricity storage device.

[0013] In the power storage device, in the first sealing portion, a region where the bonding strength between the surfaces is strong and a region where the bonding strength between the surfaces is weak may be arranged along the boundary.

[0014] In the above power storage device, in the first sealing portion, a region with a small thickness and a region with a large thickness may be arranged along the boundary.

[0015] The above electricity storage device may further include an electrode terminal electrically connected to the electrode body, and the first sealing portion may be sealed with the electrode terminal sandwiched therebetween.

[0016] The above-mentioned power storage device may further include an electrode terminal electrically connected to the electrode body and a lid body to which the electrode terminal is attached, and the exterior body may further include a second sealing portion that is sealed while joined to the lid body.

[0017] In the above electricity storage device, the lid body may include a first surface facing the electrode body and a second surface opposite the first surface, and the second sealing portion may include a portion where the exterior body and the second surface are joined.

[0018] The above-mentioned energy storage device may further include a lid body, and the exterior body may further include a second sealing portion sealed while being joined to the lid body, and the lid body may include a metal portion which is a portion having a metal layer exposed on its surface or which is made of a metal material, and the metal portion and the electrode body may be welded to each other.

[0019] In the above-mentioned energy storage device, the device may further include an electrode terminal electrically connected to the electrode body, and the exterior body may further include a protrusion that protrudes outward, and a second sealing portion that seals the electrode terminal while sandwiching it between the protrusions.

[0020] In the electricity storage device, the direction along the boundary may be a direction perpendicular to a flow direction of the exterior member.

[0021] In this electricity storage device, when the first sealing portion is folded along the boundary, the direction along the boundary is a direction perpendicular to the flow direction of the exterior member. Therefore, according to this electricity storage device, even if a crease is formed in the direction perpendicular to the flow direction of the exterior member, the exterior member is unlikely to break, and therefore it is possible to reduce the possibility that the first sealing portion will break when the first sealing portion is folded.

[0022] According to another aspect of the present invention, there is provided an electric storage device comprising an electrode assembly, an electrode terminal electrically connected to the electrode assembly, and an exterior body sealing the electrode assembly. The exterior body is made of a film-like exterior member and includes long sides and short sides in a plan view. The electrode terminal is disposed along the long sides.

[0023] An electricity storage device according to another aspect of the present invention includes an electrode body and an exterior body. The exterior body seals the electrode body. The exterior body is configured with an exterior member in a film form. The exterior body includes a piece in which the peripheral edges of surfaces that face each other when wrapped around the electrode body are joined. A base portion of the piece is formed at the boundary between surfaces in the exterior body. A space is formed within the piece in which the facing surfaces are not joined. In the piece, a region where the facing surfaces are joined and a region where the facing surfaces are not joined are aligned near the boundary.

[0024] Gas may be generated inside the exterior body. In this electricity storage device, a space is formed inside the one part, and a region where the opposing surfaces are joined and a region where the opposing surfaces are not joined are arranged near the boundary. Therefore, according to this electricity storage device, by releasing the sealed state of the exterior body at the one part, gas inside the exterior body can be discharged through the one part. Then, by sealing the exterior body again, a degassed electricity storage device can be manufactured.

[0025] A manufacturing method for an electricity storage device according to another aspect of the present invention is a manufacturing method for manufacturing an electricity storage device from an unfinished product. The unfinished product includes an electrode body and an exterior body. The exterior body seals the electrode body. The exterior body is composed of a film-shaped exterior member. The exterior body includes a piece in which peripheral edges of surfaces that face each other when the exterior member is wrapped around the electrode body are joined. A root portion of the piece is formed at a boundary between surfaces in the exterior body. A space is formed within the piece in which the facing surfaces are not joined. In the piece, a region in which the facing surfaces are joined and a region in which the facing surfaces are not joined are arranged near the boundary. The manufacturing method includes a step of releasing a sealed state of the exterior body in the piece and discharging gas to the outside of the exterior body, and a step of resealing the exterior body by joining the facing surfaces in at least a portion of the piece.

[0026] According to this method for producing an electricity storage device, the gas is discharged through one portion, and the exterior body is then sealed again, whereby a degassed electricity storage device can be produced. Effect of the Invention

[0027] According to the present invention, it is possible to provide an electricity storage device capable of suppressing unevenness in the distribution of pressure applied to a lower electricity storage device when a plurality of electricity storage devices are stacked, and a method for manufacturing the electricity storage device. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a perspective view illustrating a schematic diagram of an electricity accumulation device according to a first embodiment. [Diagram 2] FIG. 2 is a plan view illustrating a schematic diagram of the electricity storage device. [Diagram 3] FIG. 2 is a side view illustrating a schematic diagram of the electricity storage device. [Figure 4] 13 is a side view showing a state in which a packaging member is wrapped around an electrode body during manufacture of the electricity storage device according to the first embodiment. FIG. [Diagram 5] 13 is a view showing a state in which a packaging member is wrapped around an electrode body, as viewed from below, during manufacture of the electricity storage device according to the first embodiment. FIG. [Figure 6] 6 is a diagram showing a schematic view of a part of a cross section taken along line VI-VI in FIG. 2. [Figure 7] 11A to 11C are views for explaining a method of forming a second sealing portion. [Figure 8] 5 is a flowchart showing a manufacturing procedure for the electricity accumulation device according to the first embodiment. [Figure 9] FIG. 11 is a plan view illustrating a schematic diagram of an electricity accumulation device according to a second embodiment. [Figure 10] FIG. 2 is a side view illustrating a schematic diagram of the electricity storage device. [Figure 11] FIG. 2 is a perspective view showing a typical cover body. [Figure 12] FIG. 13 is a diagram showing a first example in which a lid and an electrode terminal are integrally formed. [Figure 13]FIG. 13 is a diagram showing a second example in which the cover and the electrode terminal are integrally formed. [Figure 14] 10 is a flowchart showing a manufacturing procedure for the electricity accumulation device according to the second embodiment. [Figure 15] 10 is a flowchart showing another manufacturing procedure for the electricity accumulation device according to the second embodiment. [Figure 16] FIG. 11 is a side view showing a state in which a sheath member is wrapped around an electrode body in a third embodiment. [Figure 17] FIG. 11 is a diagram showing a state in which an exterior member is wrapped around an electrode body and a lid body is attached to the exterior member, as viewed from below, in a third embodiment. [Figure 18] 13 is a flowchart showing a manufacturing procedure for the electricity accumulation device according to the third embodiment. [Figure 19] FIG. 13 is a plan view illustrating a schematic diagram of an electricity accumulation device according to a fourth embodiment. [Figure 20] FIG. 13 is a side view illustrating a schematic diagram of an electricity accumulation device according to a fourth embodiment. [Figure 21] FIG. 11 is a side view showing a state in which an exterior member is wrapped around an electrode body in a modified example. [Figure 22] FIG. 13 is a perspective view illustrating a modified example of an electricity storage device. [Figure 23] 13 is a perspective view showing a modified example of a cover and an electrode terminal attached to the cover. FIG. [Figure 24] FIG. 24 is a perspective view that illustrates a schematic diagram of an electricity accumulation device to which the lid of FIG. 23 is attached. [Diagram 25] FIG. 13 is a front view showing a schematic diagram of a cover according to another modified example. [Figure 26] FIG. 13 is a front view showing a schematic diagram of a cover according to still another modified example. [Figure 27] FIG. 11 is a plan view illustrating a schematic diagram of an electricity storage device according to another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0030] [1. Embodiment 1] <1-1. Configuration of the power storage device> FIG. 1 is a perspective view that typically shows an electricity storage device 10 according to the first embodiment. FIG. 2 is a plan view that typically shows the electricity storage device 10. FIG. 3 is a side view that typically shows the electricity storage device 10. In each of FIG. 2 and FIG. 3, the direction of arrows UD indicates the thickness direction of the electricity storage device 10, and the direction of arrows LR indicates the width direction of the electricity storage device 10. Furthermore, the direction of arrows FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UDLRFB are common to the subsequent figures.

[0031] 1, 2 and 3, the electricity storage device 10 includes an electrode body 200, an exterior body 100, and a plurality (two) of electrode terminals 300. The electrode body 200 includes electrodes (positive and negative electrodes) and separators constituting an electricity storage member such as a lithium ion battery, a capacitor, or an all-solid-state battery. The shape of the electrode body 200 is a substantially rectangular parallelepiped. Note that the term "substantially rectangular parallelepiped" includes not only a perfect rectangular parallelepiped, but also a solid body that can be regarded as a rectangular parallelepiped by modifying the shape of a portion of the outer surface, for example.

[0032] The electrode terminal 300 is a metal terminal used for inputting and outputting electric power in the electrode body 200. One end of the electrode terminal 300 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 200, and the other end protrudes outward from an edge of the exterior body 100.

[0033] The metal material constituting the electrode terminal 300 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 200 is a lithium ion battery, the electrode terminal 300 connected to the positive electrode is usually made of aluminum or the like, and the electrode terminal 300 connected to the negative electrode is usually made of copper, nickel, etc.

[0034] The exterior body 100 is composed of a film-like exterior member 101 (FIG. 4, etc.) and seals the electrode body 200. In the electricity storage device 10, the exterior body 100 is formed by wrapping the exterior member 101 around the electrode body 200 and sealing the open portion.

[0035] For example, there is a method of forming a storage portion (recess) for storing the electrode body 200 in the exterior member 101 through cold forming. However, it is not necessarily easy to form a deep storage portion by such a method. If an attempt is made to form a deep storage portion (recess) (for example, a forming depth of 15 mm) through cold forming, there is a high possibility that pinholes or cracks will occur in the exterior member, leading to a decrease in battery performance. On the other hand, since the exterior member 101 is wrapped around the electrode body 200 to seal the electrode body 200, the electrode body 200 can be easily sealed regardless of the thickness of the electrode body 200. Note that in order to reduce the dead space between the electrode body 200 and the exterior member 101 so as to improve the volumetric energy density of the electricity storage device 10, it is preferable that the exterior member 101 is wrapped around the electrode body 200 so as to come into contact with the outer surface of the electrode body 200. Moreover, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery in order to exert battery performance, and therefore it is necessary to eliminate the space between the electrode body 200 and the exterior member 101. Therefore, it is preferable that the exterior member 101 is wrapped around the electrode body 200 so as to be in contact with the outer surface of the electrode body 200.

[0036] The exterior member 101 is, for example, a laminate (laminate film) having a base layer, a barrier layer, and a heat-sealable resin layer in this order. Note that the exterior member 101 does not need to include all of these layers, and for example, it does not need to include the barrier layer. That is, the exterior member 101 only needs to be made of a material that is flexible and easily bendable, and may be made of, for example, a resin film. Note that the exterior member 101 is preferably heat-sealable.

[0037] The base material layer included in the exterior member 101 is a layer for imparting heat resistance to the exterior member 101 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base material layer is configured to include at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base material layer includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer is protected during processing of the exterior member 101 and breakage of the exterior member 101 can be suppressed. In addition, from the viewpoint of increasing the tensile elongation of the exterior member 101, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, in terms of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base material layer may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the substrate layer is, for example, preferably from 5 to 300 μm, and more preferably from 20 to 150 μm, from the viewpoint of film strength.

[0038] Moreover, the barrier layer included in the exterior member 101 is composed of, for example, aluminum foil from the viewpoints of processability such as moisture resistance and ductility, and cost. The aluminum foil preferably contains iron from the viewpoints of packaging suitability and pinhole resistance when packaging the electrode body 200. The iron content in the aluminum foil is preferably 0.5 to 5.0 mass%, and more preferably 0.7 to 2.0 mass%. When the iron content is 0.5 mass% or more, the exterior member 101 can obtain packaging suitability, excellent pinhole resistance, and ductility. When the iron content is 5.0 mass% or less, the exterior member 101 can obtain excellent flexibility.

[0039] From the viewpoints of barrier properties, pinhole resistance, and packaging suitability, the thickness of the barrier layer is, for example, preferably 15 to 100 μm, and more preferably 30 to 80 μm. When the thickness of the barrier layer is 15 μm or more, the exterior member 101 is less likely to break even when stress is applied during packaging processing. When the thickness of the barrier layer is 100 μm or less, the increase in mass of the exterior member 101 can be reduced, and a decrease in the weight energy density of the electricity storage device 10 can be suppressed.

[0040] In addition, when the barrier layer is an aluminum foil, it is preferable to provide a corrosion-resistant film at least on the surface opposite to the base layer in order to prevent dissolution and corrosion. The barrier layer may have a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (for example, acid resistance, alkali resistance, etc.) on the surface of the barrier layer by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel or chromium, or corrosion prevention treatment by applying a coating agent. Specifically, the corrosion-resistant film means a film that improves the acid resistance of the barrier layer (acid-resistant film), a film that improves the alkali resistance of the barrier layer (alkali-resistant film), etc. As a treatment for forming a corrosion-resistant film, one type may be performed, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may be included in the definition of chemical conversion treatment. In addition, when the barrier layer has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer.

[0041] The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the base layer during molding of the exterior member 101, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by the reaction between the electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the base layer and barrier layer during heat sealing and between the base layer and barrier layer during molding.

[0042] The heat-sealable resin layer included in the exterior member 101 is a layer that imparts heat-sealing sealability to the exterior member 101. Examples of the heat-sealable resin layer include a resin film made of a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride. From the viewpoints of sealability and strength, the thickness of the heat-sealable resin layer is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0043] It is preferable that the exterior member 101 has one or more layers having a buffer function (hereinafter referred to as "buffer layers") outside the heat-sealable resin layer, more preferably outside the barrier layer. The buffer layer may be laminated on the outside of the base layer, or the base layer may also have the function of the buffer layer. When the exterior member 101 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated with a base layer, a barrier layer, or the like interposed therebetween.

[0044] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. The material having cushioning properties is, for example, rubber, nonwoven fabric, or foam sheet. The rubber is, for example, natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably about 20 to 90. The material constituting the nonwoven fabric is preferably a material having excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, and more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and more preferably 3000 μm. The thickness of the buffer layer is preferably in the range of 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm. Among these, the thickness of the buffer layer is most preferably in the range of 1000 μm to 3000 μm.

[0045] When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, and more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0046] When the exterior member 101 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior member 101 from being damaged by impact when the energy storage device 10 is dropped or by handling during the manufacture of the energy storage device 10.

[0047] 4 is a side view of the electrode body 200 wrapped with the exterior member 101 during the manufacture of the electricity storage device 10. As shown in FIG. 4, the exterior member 101 is wrapped around the electrode body 200. In this case, the outermost layer of the electrode body 200 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator. With the exterior member 101 wrapped around the electrode body 200, the surfaces (thermally adhesive resin layers) of the exterior member 101 facing each other are heat sealed to form a first sealed portion 110.

[0048] The root portion of the first sealing portion 110 is on a side 135 of the exterior body 100. The side 135 is formed at the boundary between the first surface 130 and the second surface 140, which has a smaller area than the first surface 130. In other words, the root portion of the first sealing portion 110 can be said to be formed at the boundary between the first surface 130 and the second surface 140, and can be said to be not present on either the first surface 130 or the second surface 140. In the power storage device 10, the first sealing portion 110 is bent toward the second surface 140 around the side 135. In the power storage device 10, the first sealing portion 110 is in contact with the second surface 140 and covers substantially the entire second surface 140. Note that "substantially the entire second surface 140" means a region that occupies 75% or more of the area of ​​the second surface 140.

[0049] That is, in the electricity storage device 10, the first sealing portion 110 is not formed on the first surface 130 having a large area. The first surface 130 is flatter than when a sealing portion such as the first sealing portion 110 is in contact with the first surface 130. Therefore, even if another electricity storage device 10 is placed on the first surface 130, the other electricity storage device 10 does not tilt. As a result, according to the electricity storage device 10, when a plurality of electricity storage devices 10 are stacked, unevenness in the distribution of pressure applied to the lower electricity storage device 10 can be suppressed. In other words, when a module is formed by stacking a plurality of electricity storage devices 10, the first sealing portion 110 is not disposed on the surface (first surface 130) adjacent to the adjacent electricity storage device 10. In addition, such a configuration is preferable from the viewpoint that it is necessary to apply a high pressure uniformly from the outer surface of the battery in an all-solid-state battery to exhibit battery performance.

[0050] Furthermore, in the power storage device 10, a root portion of the first sealing portion 110 is on a side 135 of the exterior body 100. Therefore, according to the power storage device 10, a wider bonding area can be secured in the first sealing portion 110 compared to when the root portion of the first sealing portion 110 is on the second surface 140 (for example, the central portion of the second surface 140 in the direction of the arrow UD). Note that the bonding area of ​​the first sealing portion 110 does not necessarily need to be the entire area of ​​the first sealing portion 110, and may be a part of the first sealing portion 110, such as only the vicinity of the root portion of the first sealing portion 110.

[0051] Moreover, in the power storage device 10, substantially the entire second surface 140 is covered by the first sealing portion 110. That is, in the power storage device 10, the length of the first sealing portion 110 in the direction of the arrow UD is longer than in the case where the first sealing portion 110 covers only half or less of the area of ​​the second surface 140 (see FIG. 3). Therefore, according to the power storage device 10, a wide bonding area can be secured in the first sealing portion 110. Furthermore, since substantially the entire second surface 140 is covered by the first sealing portion 110, the power storage device 10 is stable even if the power storage device 10 is placed upright so that the second surface 140 contacts the mounting surface. That is, the power storage device 10 is unlikely to tilt with respect to the mounting surface. Therefore, such a configuration is effective, for example, when a plurality of power storage devices 10 are arranged side by side to form a module.

[0052] Fig. 5 is a view showing a state in which the exterior member 101 is wound around the electrode body 200 from below during the manufacture of the electricity storage device 10. As shown in Fig. 5, in the electricity storage device 10, the direction along the side 135 is the TD (Transverse Direction) of the exterior member 101, and the direction perpendicular to the side 135 is the MD (Machine Direction) of the exterior member 101. In other words, the direction along the side 135 is the direction (TD) perpendicular to the flow direction (MD) of the exterior member 101.

[0053] In the electricity storage device 10, the first sealing portion 110 is folded along the side 135, and the direction along the side 135 is a direction perpendicular to the flow direction of the exterior member 101. Therefore, according to the electricity storage device 10, even if a crease is formed in the direction perpendicular to the flow direction of the exterior member 101, the exterior member 101 is unlikely to break, and therefore it is possible to reduce the possibility that the first sealing portion 110 will break due to the folding of the first sealing portion 110.

[0054] The machine direction (MD) of the exterior member 101 corresponds to the rolling direction (RD) of the metal foil (aluminum alloy foil, etc.) of the barrier layer included in the exterior member 101. The TD of the exterior member 101 corresponds to the TD of the metal foil. The rolling direction (RD) of the metal foil can be determined by the rolling marks.

[0055] In addition, the sea-island structure can be confirmed by observing multiple cross sections of the heat-fusible resin layer of the exterior member 101 with an electron microscope, and the direction parallel to the cross section in which the average diameter of the islands in the direction perpendicular to the thickness direction of the heat-fusible resin layer (hereinafter also referred to as the "length direction of the heat-fusible resin layer") was maximum can be determined as the MD. When the MD of the exterior member 101 cannot be identified based on the rolling marks of the metal foil, the MD can be identified by this method.

[0056] Specifically, the sea-island structure is confirmed by observing the longitudinal cross section of the heat-sealable resin layer and each cross section (a total of 10 cross sections) at an angle of 10 degrees from the direction parallel to the longitudinal cross section and perpendicular to the longitudinal cross section. Next, for each island on each cross section, the island diameter d is measured by the linear distance connecting both ends in the direction perpendicular to the thickness direction of the heat-sealable resin layer. Next, the average of the diameters d of the top 20 largest islands is calculated for each cross section. The direction parallel to the cross section in which the average island diameter d was the largest is determined to be the MD.

[0057] Fig. 6 is a diagram that diagrammatically shows a part of the cross section taken along line VI-VI in Fig. 2. As shown in Fig. 6, second sealing portion 120 seals exterior body 100 in a state in which electrode terminal 300 is sandwiched between exterior body 100 and electrode terminal 300.

[0058] Fig. 7 is a diagram for explaining a method of forming the second sealed portion 120. As shown in Fig. 7, the exterior member 101 is folded, and the surfaces (thermally adhesive resin layers) of the exterior member 101 facing each other are heat-sealed to form the second sealed portion 120. Although omitted in Fig. 7, the electrode terminal 300 is located between the surfaces of the exterior member 101 facing each other. An adhesive film that adheres to both metal and resin may be disposed between the electrode terminal 300 and the exterior member 101.

[0059] 6 again, the electrode body 200 includes a plurality of electrodes 210 (positive and negative electrodes). A current collector 215 extending from each electrode 210 is connected to an electrode terminal 300. In the electricity storage device 10, a portion of the electrode terminal 300 that is on the outside of the exterior body 100 is located at a position that is approximately half the thickness of the electricity storage device 10 in the thickness direction of the electricity storage device 10. In other words, the length L2 is approximately half the length L1. Note that "approximately half the thickness of the electricity storage device 10" means 35% to 65% of the thickness of the electricity storage device 10.

[0060] Therefore, according to the energy storage device 10, for example, the difference between the longest distance and the shortest distance between each of the multiple electrodes 210 and the electrode terminal 300 can be made smaller compared to when the electrode terminal 300 is located at approximately the same position as the first surface 130 in the thickness direction of the energy storage device 10.

[0061] <1-2. Manufacturing method of energy storage device> Fig. 8 is a flowchart showing a manufacturing procedure of the power storage device 10. The steps shown in Fig. 8 are performed by a manufacturing apparatus for the power storage device 10, for example.

[0062] The manufacturing equipment wraps the exterior member 101 around the electrode body 200 (step S100). The manufacturing equipment forms the first sealed portion 110 by heat-sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101 (step S110). This completes the unfinished product shown in Figs. 4 and 5.

[0063] The manufacturing equipment folds the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S120). The manufacturing equipment folds the exterior member 101 in a state in which the electrode body 200 is stored, and forms the second sealing portion 120 by heat-sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101 (step S130). This completes the electricity storage device 10.

[0064] <1-3.Features> As described above, in the electricity storage device 10 according to the first embodiment, the first sealing portion 110 is folded toward the second surface 140 side having a smaller area. That is, the first sealing portion 110 does not exist on the first surface 130 having a larger area. Therefore, even if another electricity storage device 10 is placed on the first surface 130, the other electricity storage device 10 does not tilt. As a result, according to the electricity storage device 10, when a plurality of electricity storage devices 10 are stacked, unevenness in the distribution of pressure applied to the lower electricity storage device 10 can be suppressed. In addition, when used in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit the battery performance, so that the packaging form of the present invention is preferable. In addition, in the electricity storage device 10, the root portion of the first sealing portion 110 is on the side 135 of the exterior body 100. Therefore, according to the energy storage device 10, when the first sealing portion 110 is fitted onto the second surface 140, a wider bonding width can be ensured in the first sealing portion 110 compared to when the base portion of the first sealing portion 110 is located on the second surface 140.

[0065] [2. Second Embodiment] In the electricity storage device 10 according to the above-mentioned first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the mutually facing surfaces of the exterior member 101. However, the shape and the method of forming the second sealed portion 120 are not limited thereto. Note that the following mainly describes the parts that are different from the first embodiment, and the description of the parts that are common to the first embodiment will be omitted.

[0066] <2-1. Configuration of the power storage device> Fig. 9 is a plan view typically showing an electricity storage device 10X according to the second embodiment, Fig. 10 is a side view typically showing an electricity storage device 10X, and Fig. 11 is a perspective view typically showing a lid 400.

[0067] 9, 10, and 11, the exterior body 100X is formed by fitting a lid body 400 into each of the openings at both ends of an exterior member 101 wrapped around an electrode assembly 200. With the lid body 400 fitted in, the exterior member 101 and the lid body 400 are heat-sealed to form a second sealed portion 120X.

[0068] The lid body 400 is a bottomed tray-like member having a rectangular shape in a plan view, and is formed by, for example, cold forming the exterior member 101. The lid body 400 does not necessarily have to be made of the exterior member 101, and may be a metal molded product or a resin molded product. In the power storage device 10X, the lid body 400 is arranged so that the bottom side of the lid body 400 is located inside the exterior body 100X. In the power storage device 10X, the bottom side of the lid body 400 does not necessarily have to be located inside the exterior body 100X. In the power storage device 10X, the bottom side of the lid body 400 may be located outside the exterior body 100X.

[0069] In addition, when the electrode body 200 is stored, the electrode terminal 300 passes between the lid body 400 and the exterior member 101 and protrudes to the outside of the exterior body 100X. That is, the lid body 400 and the exterior member 101 are heat sealed with the electrode terminal 300 sandwiched between them. In the power storage device 10X, the position where the electrode terminal 300 protrudes to the outside does not necessarily have to be between the lid body 400 and the exterior member 101. For example, the electrode terminal 300 may protrude to the outside from a hole formed on any one of the six surfaces of the exterior body 100X. In this case, a small gap between the exterior body 100X and the electrode terminal 300 is filled with, for example, resin.

[0070] Furthermore, in the power storage device 10X, the lid body 400 and the electrode terminal 300 are provided as separate bodies. However, the lid body 400 and the electrode terminal 300 do not necessarily have to be provided as separate bodies. For example, the lid body 400 and the electrode terminal 300 may be formed integrally.

[0071] Fig. 12 is a diagram showing a first example in which the lid body 400 and the electrode terminal 300 are integrally formed. As shown in Fig. 12, in the first example, the electrode terminal 300 is heat-sealed in advance to the side surface of the lid body 400. Note that, for example, when the lid body 400 is made of an exterior member 101, an adhesive film that adheres to both metal and resin may be disposed between the lid body 400 and the electrode terminal 300.

[0072] Fig. 13 is a diagram showing a second example in which the lid 400 and the electrode terminal 300 are integrally formed. As shown in Fig. 13, in the second example, the electrode terminal 300 passes through a hole formed in the bottom surface portion of the lid 400. A small gap in the hole in the bottom surface of the lid 400 is filled with, for example, resin.

[0073] Furthermore, in the power storage device 10X, a gas valve may be attached to a hole formed in the second sealing portion 120X or any one of six faces of the exterior body 100X. The gas valve is configured, for example, as a check valve or a breaker valve, and is configured to reduce the pressure inside the exterior body 100X when the pressure increases due to gas generated inside the power storage device 10X.

[0074] <2-2. Manufacturing method of electricity storage device> Fig. 14 is a flowchart showing a manufacturing procedure for the power storage device 10X. The steps shown in Fig. 14 are performed, for example, by a manufacturing apparatus for the power storage device 10X.

[0075] The manufacturing equipment wraps the exterior member 101 around the electrode body 200 (step S200). The manufacturing equipment forms the first sealed portion 110 by heat-sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101 (step S210). This completes the unfinished product shown in Figs. 4 and 5.

[0076] The manufacturing equipment bends the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S220). The manufacturing equipment houses the electrode body 200 in the unfinished product produced in step S220 and attaches the lid body 400 to each of the openings at both ends (step S230). The manufacturing equipment forms the second sealing portion 120X by heat-sealing the exterior member 101 and the lid body 400 (step S240). This completes the electricity storage device 10X.

[0077] <2-3.Features> In the power storage device 10X according to the second embodiment, the first sealing portion 110 is also bent toward the second surface 140 having the smaller area. Therefore, according to the power storage device 10X, when a plurality of power storage devices 10X are stacked, unevenness in the distribution of pressure applied to the lower power storage device 10X can be suppressed.

[0078] <2-4.Other features> In the power storage device 10X according to the second embodiment, the first sealing unit 110 does not necessarily have to be bent towards the second surface 140 having a smaller area. For example, the first sealing unit 110 may be bent towards the first surface 130 having a larger area. Furthermore, the root portion of the first sealing unit 110 does not necessarily have to be on the side 135 of the exterior body 100X. The root portion of the first sealing unit 110 may be located on a surface of the exterior body 100X other than the lid body 400, for example. Even in this case, the power storage device 10X according to the second embodiment includes, for example, the following features.

[0079] The energy storage device 10X comprises an electrode body (electrode body 200) and an exterior body (exterior body 100X) that seals the electrode body (electrode body 200). The exterior body (exterior body 100X) is wrapped around the electrode body (electrode body 200) and comprises an exterior member (exterior member 101) having openings formed at both ends, and a lid body (lid body 400) that seals the openings.

[0080] In the electricity storage device 10X, the second sealed portion 120X is not formed by heat sealing mutually facing surfaces of the exterior member 101 as in the first embodiment (see FIG. 7). In the electricity storage device 10X, the opening of the exterior member 101 wrapped around the electrode body 200 is sealed by the lid body 400. That is, the second sealed portion 120X is formed in the portion where the lid body 400 and the exterior member 101 overlap (see FIGS. 9 and 10). With this configuration, the area of ​​the second sealed portion 120X can be easily narrowed by adjusting the depth L3 (FIG. 11) of the lid body 400.

[0081] Furthermore, in the electricity storage device 10X, at a position of the exterior member 101 that covers the corner C1 (FIGS. 9 and 10) of the electrode body 200, no excessive load is generated due to the corner C1 piercing the exterior member 101. This is because, as described above, in the electricity storage device 10X, the second sealed portion 120X is not formed by heat sealing mutually facing surfaces of the exterior member 101 as in the first embodiment.

[0082] Furthermore, the manufacturing procedure of the power storage device 10X is not limited to the procedure shown in the flowchart of Fig. 14. For example, the power storage device 10X may be manufactured according to the procedure shown in the flowchart of Fig. 15.

[0083] FIG. 15 is a flowchart showing another manufacturing procedure of the power storage device 10X according to the second embodiment. The steps shown in FIG. 15 are performed, for example, by a manufacturing apparatus for the power storage device 10X. The manufacturing apparatus attaches a member (for example, a member shown in FIGS. 12 and 13) in which the electrode terminal 300 and the lid body 400 are integrated to the electrode body 200 (step S250). For example, the electrode terminal 300 is welded to the electrode body 200. Thereafter, the manufacturing apparatus wraps the exterior member 101 around the electrode body 200 (step S260). The manufacturing apparatus forms the first sealed portion 110 by heat-sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101, and forms the second sealed portion 120X by heat-sealing the exterior member 101 and the lid body 400 together (step S270). This completes the power storage device 10X. The power storage device 10X may be manufactured by such a procedure.

[0084] [3. Embodiment 3] In a battery manufacturing process, a temporarily sealed electricity storage device is generally subjected to a process of aging in a predetermined temperature environment for a predetermined time for the purpose of permeating an electrolyte into the electrode body (hereinafter referred to as an aging process). In the aging process, gas is generated from the electrode body 200, and it is necessary to discharge the gas to the outside of the battery. In the electricity storage device 10X according to the above-mentioned second embodiment, no mechanism is provided for releasing the gas generated in the aging process in the final stage of manufacturing the electricity storage device 10X. In the electricity storage device 10Y according to the third embodiment, a mechanism is provided for releasing the gas generated from the electrode body 200 in the final stage of manufacturing the electricity storage device 10Y. In the following, differences from the second embodiment will be mainly described, and a description of the parts common to the second embodiment will be omitted.

[0085] <3-1. Configuration of the power storage device> Fig. 16 is a side view showing a state in which the exterior member 101Y is wrapped around the electrode body 200 during the manufacture of the electricity storage device 10Y. Fig. 17 is a bottom view showing a state in which the exterior member 101Y is wrapped around the electrode body 200 and a lid body 400 is attached to the exterior member 101Y during the manufacture of the electricity storage device 10Y.

[0086] As shown in Fig. 16 and Fig. 17, the piece 150 is formed in a state where the exterior member 101Y is wound around the electrode body 200. The piece 150 is formed by joining mutually facing surfaces of the exterior member 101Y in a state where the exterior member 101Y is wound around the electrode body 200. More specifically, the piece 150 is formed by joining (heat sealing) the peripheries of the mutually facing surfaces in a state where the exterior member 101Y is wound around the electrode body 200. That is, in the piece 150, a first sealed portion 154 is formed on the periphery.

[0087] Further, in the piece 150, a space 152 is formed where the opposing surfaces of the exterior member 101Y are not joined to each other. In the vicinity of the side 135, a joining region 151 where the opposing surfaces of the exterior member 101Y are joined to each other and an unjoined region 153 where the opposing surfaces of the exterior member 101Y are not joined to each other are arranged alternately. That is, in the piece 150, a pattern of the joining region 151 is formed along the side 135.

[0088] The gas generated from the electrode body 200 is discharged to the outside of the exterior body 100Y by releasing the sealed state of the exterior body 100Y, for example by cutting off a part of the piece 150. Note that the gas discharged to the outside of the exterior body 100Y here is not necessarily limited to the gas generated from the electrode body 200, and may be a gas other than the gas generated from the electrode body 200, such as air, water vapor, or hydrogen sulfide.

[0089] Thereafter, the portion including the vicinity of the side 135 is heat-sealed in a strip shape, thereby sealing the exterior body 100Y again. This completes the electricity storage device 10Y. In the completed electricity storage device 10Y, in the vicinity of the side 135, regions where the bonding strength between the mutually facing surfaces of the exterior member 101Y is strong and regions where the bonding strength between the surfaces is weak are alternately arranged along the side 135. In other words, in the heat-sealed portion in the vicinity of the side 135, thin portions and thick portions are alternately arranged along the side 135. This is because, by heat-sealing the vicinity of the side 135 again, the unbonded region 153 is single-sealed, but the bonded region 151 is double-sealed.

[0090] <3-2. Manufacturing method of electricity storage device> Fig. 18 is a flowchart showing a manufacturing procedure for the power storage device 10Y. The steps shown in Fig. 18 are performed, for example, by a manufacturing apparatus for the power storage device 10Y.

[0091] The manufacturing equipment wraps the exterior member 101Y around the electrode body 200 (step S300). The manufacturing equipment forms the first sealed portion 154 by heat-sealing the peripheral edges of the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101Y (step S310). The manufacturing equipment forms a pattern of the bonding region 151 by heat-sealing the mutually facing surfaces of the exterior member 101Y in the vicinity of the side 135 (step S320).

[0092] The manufacturing equipment attaches the lid body 400 to each of the openings at both ends with the electrode body 200 housed in the unfinished product produced in step S320 (step S330). The manufacturing equipment forms the second sealed portion 120X by heat-sealing the exterior member 101Y and the lid body 400 (step S340). Then, an aging process is performed.

[0093] The manufacturing equipment removes gas generated in the aging process by, for example, cutting off piece 150 (step S350). The manufacturing equipment reseals exterior body 100Y by heat-sealing a portion of piece 150 including bonding region 151 into a strip shape and removing the edge portion (step S360). Thereafter, piece 150 is folded toward second surface 140 to complete electricity storage device 10Y.

[0094] <3-3.Features> In the electricity storage device 10Y according to the third embodiment, the piece 150 including the first sealing portion 154 is also folded toward the second surface 140 having a smaller area. Therefore, according to the electricity storage device 10Y, when a plurality of electricity storage devices 10Y are stacked, unevenness in the distribution of pressure applied to the lower electricity storage device 10Y can be suppressed. When used in an all-solid-state battery, it is necessary to apply high pressure uniformly from the outer surface of the battery to exhibit battery performance, and therefore the packaging form of the present invention is preferable.

[0095] [4. Embodiment 4] In the power storage device 10X according to the above-described second embodiment, the position from which the electrode terminal 300 protrudes to the outside is between the lid body 400 and the exterior member 101. However, the position from which the electrode terminal 300 protrudes to the outside is not limited thereto. Note that the following description will focus on the parts that are different from the second embodiment, and a description of the parts that are common to the second embodiment will be omitted.

[0096] <4-1. Configuration of the power storage device> FIG. 19 is a plan view that typically shows an electricity storage device 10XA according to the fourth embodiment. FIG. 20 is a side view that typically shows the electricity storage device 10XA. The exterior body 100X of the electricity storage device 10XA includes a pair of long sides 100XA and a pair of short sides 100XB in a plan view. The exterior body 100X is configured by fitting a lid body 400 into each of the openings along the long sides 100XA of an exterior member 101 that is wrapped around the electrode body 200. With the lid body 400 fitted in, the exterior member 101 and the lid body 400 are heat-sealed to form a second sealed portion 120X. A through hole (not shown) is formed in the lid body 400. The two electrode terminals 300 protrude from the through holes of the lid body 400 to the outside of the exterior body 100X. The two electrode terminals 300 are shaped to fit along the long side 100XA of the exterior body 100X. Small gaps between the through holes and the electrode terminals 300 are filled with, for example, resin. In the fourth embodiment, the first sealing portion 110 is formed on one of the pair of short sides 100XB.

[0097] In the thickness direction (arrow UD direction) of the power storage device 10XA, the position from which the electrode terminal 300 of the lid body 400 protrudes can be selected arbitrarily. In the fourth embodiment, as shown in FIG. 20, the electrode terminal 300 protrudes from approximately the center of the lid body 400 to the outside of the exterior body 100X in the thickness direction of the power storage device 10XA. The length of the electrode terminal 300 in the depth direction (arrow FB direction) of the power storage device 10XA can be selected arbitrarily. In the fourth embodiment, the length of the electrode terminal 300 in the depth direction (arrow FB direction) of the power storage device 10XA is substantially the same as the length of the electrode body 200.

[0098] <4-2.Features> In the power storage device 10XA according to the fourth embodiment, the electrode terminals 300 are arranged along the long side 100XA that is longer in the depth direction, so that it is possible to use larger electrode terminals 300. This makes it possible to provide a high-output power storage device 10XA.

[0099] [5. Modifications] Although the embodiments 1 to 4 have been described above, the present invention is not limited to the above embodiments 1 to 4, and various modifications are possible without departing from the spirit of the present invention. Modifications will be described below.

[0100] <5-1> In the above-mentioned embodiments 1-4, one exterior member is wound around the electrode assembly 200. However, it is not necessary to wind one exterior member around the electrode assembly 200. For example, two or more exterior members may be wound around the electrode assembly 200.

[0101] FIG. 21 is a side view showing a state in which the exterior members 101Z1 and 101Z2 are wound around the electrode body 200 during the manufacturing process of the electric storage device in the modified example. As shown in FIG. 21, the electrode body 200 is covered with the exterior members 101Z1 and 101Z2. The first sealing portion 110Z is formed by joining the opposing surfaces of the exterior members 101Z1 and 101Z2. In this example, each first sealing portion 110Z is folded toward the second surface 140Z side, not toward the first surface 130Z side. Even with this configuration, it is possible to achieve the effect of suppressing unevenness in the distribution of pressure applied to the lower electric storage device when multiple electric storage devices are stacked. When used in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit battery performance, so the packaging form of the present invention is preferable. In this example, each first sealing portion 110Z does not necessarily need to be folded. In this modification, each sealing portion 110Z may be sealed in a state in which it sandwiches a part of the electrode terminal 300. Furthermore, in this modification, each first sealing portion 110Z does not need to be formed on the side 135Z, and may protrude outward from approximately the center of the second surface 140Z in the thickness direction of the power storage device.

[0102] <5-2> In addition, in the above-mentioned embodiments 1-4, the electrode body 200 is a so-called stack type configured by stacking a plurality of electrodes 210, but the form of the electrode body 200 is not limited to this. The electrode body 200 may be, for example, a so-called wound type configured by winding a positive electrode and a negative electrode via a separator. The electrode body 200 may also be configured by stacking a plurality of so-called wound type electrode bodies.

[0103] <5-3> In the above-mentioned embodiment 1-4, the second surface 140 is a plane extending downward from the first surface 130 at a substantially right angle. However, the form of the second surface 140 is not limited to this. For example, consider a case where the electrode body 200 is a wound electrode body having a plane surface and a curved surface formed on the outer periphery. Here, it is assumed that the area of ​​the plane surface is larger than the area of ​​the curved surface, the first surface 130 covers the plane surface of the electrode body, and the second surface 140 covers the curved surface of the electrode body. In this case, the second surface 140 may be configured as a curved surface. In this case, the boundary portion where the second surface 140 extends downward from the first surface 130 is the side 135.

[0104] <5-4> In the third embodiment, bonding regions 151 are formed in four locations. However, the number of locations where bonding regions 151 are formed is not limited to this. For example, bonding regions 151 may be formed in two locations near both ends along side 135, in one location near the center of side 135, or in five or more locations.

[0105] <5-5> In the first embodiment, the electrode terminal 300 is disposed in the second sealing portion 120, but the position at which the electrode terminal 300 is disposed in the exterior body 100 is not limited thereto. For example, as shown in FIG. 22, the electrode terminal 300 can also be disposed in the first sealing portion 110. In other words, the first sealing portion 110 is sealed in a state in which the electrode terminal 300 is sandwiched between them. In this modification, at least one of the two electrode terminals 300 may be folded toward the second surface 140, may be folded toward the opposite side to the second surface 140, or may not be folded so as to protrude outward from the side 135. In this modification, the electrode terminal 300 and the first sealing portion 110 can be easily sealed, so that the sealing property of the exterior body 100 is improved. In addition, the electrode body 200 can be easily accommodated in the exterior body 100. In this modification, for example, the lid body 400 is fitted into each of the openings at both ends of the exterior member 101 as in the second embodiment. With the lid 400 fitted in place, the exterior member 101 and the lid 400 are heat sealed together to form the second sealed portion 120.

[0106] <5-6> In addition, in the above-mentioned second embodiment, the configuration of the lid body 400 can be arbitrarily changed. FIG. 23 is a perspective view showing a lid body 500 of a modified example of the lid body 400. The lid body 500 is, for example, plate-shaped, and includes a first surface 500A facing the electrode body 200 (see FIG. 9), and a second surface 500B opposite to the first surface 500A. A hole 500C penetrating the first surface 500A and the second surface 500B is formed in the center of the lid body 500. The material constituting the lid body 500 is, for example, a resin. In this modified example, it is preferable that an adhesive film 530 that adheres to both the electrode terminal 300 and the lid body 500 is attached to a predetermined range including a portion of the electrode terminal 300 that is joined to the lid body 500. The lid 500 may be manufactured by being composed of a member divided into a first portion 510 and a second portion 520, and the first portion 510 and the second portion 520 are joined together so as to sandwich the electrode terminal 300 and the adhesive film 530. The lid 500 may also be manufactured by insert molding the lid 500 onto the electrode terminal 300 to which the adhesive film 530 is attached. In this modification, it is preferable that a barrier layer is laminated on at least a part of the surface of the lid 500. Alternatively, when the lid 500 has a plurality of layers, a barrier layer may be formed on any layer. The material constituting the barrier layer is, for example, aluminum. In this modification, when a gap occurs between the adhesive film 530 and the hole 530C, the gap is preferably filled with a resin material such as hot melt.

[0107] 24, in the exterior body 100X, the second sealing portion 120X is formed by joining the exterior member 101 and the second surface 500B of the lid body 500 with the lid body 500 fitted therein. The joining means between the exterior member 101 and the second surface 500B of the lid body 500 is, for example, heat sealing. In this modification, the exterior member 101 is joined to a wider area of ​​the lid body 500, thereby improving the sealing performance of the exterior body 100X.

[0108] FIG. 25 is a front view of a lid body 600 of another modified example of the lid body 400 in the above-mentioned embodiment 2. The lid body 600 includes a metal part 610 that is a part where a metal is exposed on the surface, and the metal part 610 and the electrode 210 of the electrode body 200 are welded. The lid body 600 may be entirely composed of the metal part 610, or the metal part 610 may be partially formed. When the metal part 610 is partially formed, the lid body 600 is composed of a material having a multilayer structure including a metal layer. When the lid body 600 is composed of a material having a multilayer structure with a metal layer as an intermediate layer, the metal part 610 is a part where layers other than the metal layer are partially removed so that the metal layer is exposed. In the example shown in FIG. 25, the metal part 610 of the lid body 600 functions as an electrode terminal, so that a space between the lid body 600 and the electrode 210 is not required. Therefore, the electricity storage device 10X (see FIG. 9) can be configured to be small.

[0109] Fig. 26 is a front view of a lid body 700 which is another modified example of the lid body 400 in the above-mentioned embodiment 2. The lid body 700 includes a metal portion 710 made of a metal material, and a non-metal portion 720 connected to the metal portion 710 and made of a resin material. The metal portion 710 is welded to the electrode 210 of the electrode body 200. In the example shown in Fig. 26, the metal portion 710 of the lid body 700 functions as an electrode terminal, so that no space is required between the lid body 700 and the electrode 210. Therefore, the electricity storage device 10X (see Fig. 9) can be configured to be small in size.

[0110] <5-7> In the first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the thermally adhesive resin layers of the exterior member 101. However, the method of forming the second sealed portion 120 is not limited to this. FIG. 27 is a plan view that shows a schematic diagram of an electricity storage device 10 having a second sealed portion 120Y of a modified example. The exterior member 101 has a protruding portion 101X that extends outward from the exterior body 100, and the thermally adhesive resin layers of the protruding portion 101X are heat-sealed to each other to form the second sealed portion 120Y. In the portion of the protruding portion 101X where the electrode terminal 300 is disposed, the thermally adhesive resin layer of the protruding portion 101X and the electrode terminal 300 are heat-sealed. According to this modified example, the second sealed portion 120Y can be heat-sealed more firmly, and therefore the hermeticity of the exterior body 100 is improved. In this modification, the protruding portion 101X may be cut as necessary except for the portion that is heat sealed to the electrode terminal 300. This modification can also be applied to the modification shown in FIG. [Explanation of symbols]

[0111] 10, 10X, 10XA, 10Y, 10Z Electric storage device, 100, 100X, 100Y Exterior body, 101, 101Y, 101Z1, 101Z2 Exterior member, 101X Protruding portion, 110, 110Z, 154 First sealing portion, 120, 120X, 120Y Second sealing portion, 130, 130Z First surface, 135, 135Z Side, 140, 140Z Second surface, 150 Side portion, 151 Bonding area, 152 Space, 153 Unbonded area, 200 Electrode body, 210 Electrode, 215 Current collector, 300 Electrode terminal, 500A First surface, 500B Second surface, 400, 500, 700 Lid body, 610, 710 Metal part, C1 corner.

Claims

1. An electrode body; an electrode terminal electrically connected to the electrode body; and an exterior body that seals the electrode body, The exterior body is a film-like exterior member that is wrapped around the electrode body so as to have an opening; a cover body to which the electrode terminal is attached and which is fitted into the opening of the exterior member; a first sealing portion that is sealed by joining surfaces that face each other in a state where the exterior member is wrapped around the electrode body, a base portion of the first sealing portion is formed at a boundary between a first surface and a second surface of the exterior body, the lid has a through hole into which the electrode terminal is inserted, The first sealing portion is bent toward the second surface side. Energy storage device.

2. The area of ​​the first surface is greater than the area of ​​the second surface. The power storage device according to claim 1 .

3. The first sealing portion, when bent toward the second surface, covers substantially the entire second surface. The electricity storage device according to claim 1 or 2.

4. The exterior member includes a barrier layer, The barrier layer comprises a corrosion resistant coating. The electricity storage device according to any one of claims 1 to 3.

5. The barrier layer is made of aluminum foil, The iron content in the aluminum foil is in the range of 0.5% by mass to 5.0% by mass. The electricity storage device according to claim 4 .

6. The lid is a resin molded product or a metal molded product (excluding films). The electricity storage device according to any one of claims 1 to 5.

7. The lid is a plate-shaped member. The electricity storage device according to any one of claims 1 to 5.

8. The lid is a tray-like member (excluding the film) having a bottom and a rectangular shape in a plan view. The electricity storage device according to any one of claims 1 to 5.

9. the lid body includes a metal portion which is a portion having a metal layer exposed on a surface thereof or a portion made of a metal material, The metal portion and the electrode body are welded together. The electricity storage device according to any one of claims 1 to 8.

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