Power storage device and method for manufacturing the same

Abstract

To provide a power storage device capable of suppressing unevenness in the distribution of pressure applied to adjacent power storage devices when multiple power storage devices are stacked, and a method for manufacturing the power storage device.SOLUTION: A power storage device includes an electrode body and an exterior body. The exterior body seals the electrode body. The exterior body is made of a film-like exterior member. The exterior body includes a first sealing portion sealed by joining opposing surfaces together when wrapped around the electrode body. A base 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 with 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 Patent Document 1, a laminate film seal is provided on a surface with a large area. The seal is an area where the films overlap, so it is thicker than other areas. When other secondary batteries are stacked on the surface with the seal, the upper secondary battery may tilt with the seal as a fulcrum. As a result, the distribution of pressure applied to the lower secondary battery becomes more uneven. Furthermore, when multiple secondary batteries are arranged horizontally so that the surface with the seal is in contact with the adjacent secondary battery, the distribution of pressure applied from the adjacent secondary battery also becomes more uneven.

[0005] The present invention has been made to solve such problems, and its purpose is to provide an electricity storage device and a method for manufacturing the 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 one aspect of the present invention includes an electrode body and an exterior body. The exterior body seals the electrode body. The exterior body is made of a film-like exterior member. The exterior body includes a first sealing portion sealed by joining opposing surfaces of the exterior member when the exterior member is wrapped around the electrode body. A base 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 with the first surface in a plan view.

[0007] In this energy storage device, the first sealing portion does not overlap the first surface having a larger area in a plan view. In other words, the first sealing portion is not present on the first surface having a larger area. Therefore, even if another energy storage device is placed on top of or next to the first surface, the other energy storage device will not tilt. As a result, this energy storage device can suppress unevenness in the distribution of pressure applied to adjacent energy storage devices when multiple energy storage devices are stacked. Furthermore, in this energy storage device, the base of the first sealing portion is located on the boundary between the first surface and the second surface of the exterior body. Therefore, with this energy storage device, when the first sealing portion is placed on the second surface, a wider joint width can be ensured in the first sealing portion compared to when the base of the first sealing portion is located on the second surface.

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

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

[0010] According to 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 above-mentioned energy storage device may further include an electrode terminal electrically connected to the electrode body, and the outer casing may further include a second sealing portion sealed with the electrode terminal sandwiched therebetween, a portion of the electrode terminal being located outside the outer casing, and a base portion of the portion may be located at a position approximately halfway through the thickness of the energy storage device in the thickness direction of the energy 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 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 and shortest distances between each of the multiple electrodes included in the electrode body and the electrode terminal, compared to when 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 above 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 thin region and a thick region may be arranged along the boundary.

[0015] The above-described 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 energy 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-mentioned 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 portion where a metal layer is exposed on the surface or a metal portion which is a portion made of a metal material, and the metal portion and the electrode body may be welded.

[0019] The above-mentioned energy storage device may further include an electrode terminal electrically connected to the electrode body, and the outer casing may further include a protruding portion that protrudes outward and a second sealing portion that seals the electrode terminal while sandwiching it between the protruding portions.

[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 perpendicular to the flow direction of the exterior member. Therefore, with this electricity storage device, even if a fold is formed in the direction perpendicular to the flow direction of the exterior member, the exterior member is unlikely to break, and therefore, the possibility of the first sealing portion breaking when the first sealing portion is folded can be reduced.

[0022] An electricity storage device according to another aspect of the present invention includes 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 arranged 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 constituted by a film-like exterior member. The exterior body includes a piece portion in which the peripheral edges of surfaces that face each other when wrapped around the electrode body are joined. The base portion of the piece is formed at the boundary between the surfaces of the exterior body. A space is formed within the piece portion in which the facing surfaces are not joined. In the piece portion, a region in which the facing surfaces are joined and a region in which the facing surfaces are not joined are aligned near the boundary.

[0024] Gas may be generated within the exterior body. In this electricity storage device, a space is formed within the one half, 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, with this electricity storage device, by releasing the sealed state of the exterior body at the one half, gas within the exterior body can be discharged through the one half. Then, by resealing the exterior body, the 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 assembly and an exterior body. The exterior body seals the electrode assembly. The exterior body is composed of a film-like exterior member. The exterior body includes pieces where the peripheral edges of surfaces that face each other when the exterior member is wrapped around the electrode assembly are joined. The base portions of the pieces are formed at the boundary between surfaces of the exterior body. A space is formed within the piece where 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. The manufacturing method includes a step of releasing the sealed state of the exterior body at 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 manufacturing an electricity storage device, the gas is discharged through one of the parts, and the exterior body is sealed again, thereby manufacturing a degassed electricity storage device. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide an electricity storage device that can suppress 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 explanation of the drawings]

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

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals 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 schematically shows an electricity storage device 10 according to the first embodiment. FIG. 2 is a plan view that schematically shows the electricity storage device 10. FIG. 3 is a side view that schematically shows the electricity storage device 10. In each of FIGS. 2 and 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 that constitute 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" refers not only to a perfect rectangular parallelepiped, but also to a solid that can be regarded as a rectangular parallelepiped by modifying the shape of a portion of its outer surface, for example.

[0032] The electrode terminal 300 is a metal terminal used for inputting and outputting power to and from 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 the 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, etc., and the electrode terminal 300 connected to the negative electrode is usually made of copper, nickel, etc.

[0034] The exterior body 100 is made of a film-like exterior member 101 (see 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) in the exterior member 101 through cold forming to store the electrode assembly 200. However, it is not necessarily easy to form a deep storage portion using such a method. If an attempt is made to form a deep storage portion (recess) through cold forming (for example, a forming depth of 15 mm), pinholes and cracks are likely to occur in the exterior member, leading to a decrease in battery performance. On the other hand, the exterior member 100 seals the electrode assembly 200 by wrapping the exterior member 101 around the electrode assembly 200, so the electrode assembly 200 can be easily sealed regardless of the thickness of the electrode assembly 200. Note that in order to reduce the dead space between the electrode assembly 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 be wrapped so as to come into contact with the outer surface of the electrode assembly 200. Furthermore, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery 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 contact the outer surface of the electrode body 200.

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

[0037] The substrate layer included in the exterior member 101 is a layer that imparts heat resistance to the exterior member 101 and suppresses the occurrence of pinholes that may occur during processing or distribution. The substrate layer is composed of, for example, at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer in the substrate layer, the barrier layer can be protected during processing of the exterior member 101, and breakage of the exterior member 101 can be suppressed. Furthermore, 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, from the viewpoint 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 substrate layer may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the substrate layer is preferably, for example, 5 to 300 μm, more preferably 20 to 150 μm, from the viewpoint of film strength.

[0038] Furthermore, the barrier layer included in the packaging member 101 is made of, for example, aluminum foil from the standpoint of processability such as moisture resistance and ductility, and cost. The aluminum foil preferably contains iron from the standpoints 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 %. An iron content of 0.5 mass % or more ensures packaging suitability, excellent pinhole resistance, and ductility for the packaging member 101. Furthermore, an iron content of 5.0 mass % or less ensures excellent flexibility for the packaging member 101.

[0039] From the viewpoints of barrier properties, pinhole resistance, and packaging suitability, the thickness of the barrier layer is preferably, for example, 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, an increase in the 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] Furthermore, when the barrier layer is an aluminum foil, it is preferable to provide a corrosion-resistant coating on at least the surface opposite the substrate layer to prevent dissolution and corrosion. The barrier layer may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by applying, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent to the surface of the barrier layer. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer (acid-resistant coating) or a coating that improves the alkali resistance of the barrier layer (alkali-resistant coating). The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, not only one layer but also multiple layers can be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments that dissolve the metal foil surface with a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may also be included in the definition of chemical conversion treatment. In addition, when the barrier layer is provided with 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 (for example, 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 water, 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 provides heat-sealing properties 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 sealing properties 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] The exterior member 101 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") 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 function as a 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. Examples of the material having cushioning properties include rubber, nonwoven fabric, and foam sheet. Examples of rubber include natural rubber, fluororubber, and 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 even 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 even 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, and 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 buffer layer thickness is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the buffer layer thickness 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 an 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 showing a state in which a packaging member 101 is wrapped around the electrode body 200 during the manufacturing process of the electricity storage device 10. As shown in FIG. 4, the packaging 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 packaging member 101 wrapped around the electrode body 200, the surfaces (thermally adhesive resin layers) of the packaging member 101 facing each other are heat-sealed to form a first sealing portion 110.

[0048] A base portion of the first sealing unit 110 is located 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 base portion of the first sealing unit 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 located on neither the first surface 130 nor the second surface 140. In the energy storage device 10, the first sealing unit 110 is bent toward the second surface 140 around the side 135. In the energy storage device 10, the first sealing unit 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, which has 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 will not tilt. As a result, the electricity storage device 10 can suppress unevenness in the distribution of pressure applied to the lower electricity storage device 10 when multiple electricity storage devices 10 are stacked. In other words, when multiple electricity storage devices 10 are stacked to form a module, the first sealing portion 110 is not disposed on the surface (first surface 130) adjacent to the adjacent electricity storage device 10. Furthermore, such a configuration is preferable from the viewpoint that in all-solid-state batteries, high pressure needs to be applied uniformly from the outer surface of the battery to exhibit battery performance.

[0050] Furthermore, in the power storage device 10, the base portion of the first sealing portion 110 is located on the side 135 of the exterior body 100. Therefore, with the power storage device 10, a wider bonding area 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 (for example, in 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 have 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 base portion of the first sealing portion 110.

[0051] Furthermore, in the electricity storage device 10, substantially the entire second surface 140 is covered by the first sealing portion 110. That is, in the electricity storage device 10, the length of the first sealing portion 110 in the direction of the arrow UD is longer than in a 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 electricity 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 electricity storage device 10 is stable even if the electricity storage device 10 is placed upright so that the second surface 140 is in contact with a mounting surface. That is, the electricity storage device 10 is unlikely to tilt relative to the mounting surface. Therefore, such a configuration is effective, for example, when a plurality of electricity storage devices 10 are arranged side by side to form a module.

[0052] Fig. 5 is a view showing, from below, a state in which the exterior member 101 is wrapped around the electrode assembly 200 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 transverse direction (TD) of the exterior member 101, and the direction perpendicular to the side 135 is the machine direction (MD) 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 unit 110 is folded along the side 135, and the direction along the side 135 is 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 unit 110 will break when the first sealing unit 110 is folded.

[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] Furthermore, 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 the largest can be determined as the MD. When the MD of the exterior member 101 cannot be identified by 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 electron microscope photographs of a cross section of the heat-sealable resin layer in the longitudinal direction and cross sections at angles of 10 degrees from the direction parallel to the longitudinal cross section, up to a direction perpendicular to the longitudinal cross section (a total of 10 cross sections). Next, for each island on each cross section, the island diameter d is measured as the linear distance connecting both ends in the direction perpendicular to the thickness direction of the heat-sealable resin layer. Next, the average diameter d of the 20 largest islands is calculated for each cross section. The direction parallel to the cross section with the largest average island diameter d is then determined as the MD.

[0057] Fig. 6 is a diagram schematically showing a part of the cross section taken along line VI-VI in Fig. 2. As shown in Fig. 6, second sealing portion 120 seals electrode terminal 300 in a state where package 100 sandwiches electrode terminal 300 therebetween.

[0058] 7 is a diagram illustrating a method for 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 that face each other are heat-sealed to form the second sealed portion 120. Although not shown in FIG. 7, the electrode terminal 300 is located between the surfaces of the exterior member 101 that face 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 assembly 200 includes a plurality of electrodes 210 (positive and negative electrodes). Current collectors 215 extending from each electrode 210 are connected to an electrode terminal 300. In the electricity storage device 10, a portion of the electrode terminal 300 that is outside 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, the difference between the longest and shortest distances between each of the multiple electrodes 210 and the electrode terminal 300 can be made smaller than when, for example, 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> 8 is a flowchart showing a manufacturing procedure for the power storage device 10. The steps shown in FIG.

[0062] The manufacturing equipment wraps the exterior member 101 around the electrode body 200 (step S100). The manufacturing equipment heat-seals the surfaces (thermal adhesive resin layers) of the exterior member 101 that face each other to form the first sealed portion 110 (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 with the electrode body 200 stored therein, and forms the second sealing portion 120 by heat-sealing the surfaces (thermal adhesive resin layers) of the exterior member 101 that face each other (step S130). This completes the electricity storage device 10.

[0064] <1-3. Features> As described above, in the energy storage device 10 according to the first embodiment, the first sealing portion 110 is bent toward the second surface 140, which has a smaller area. That is, the first sealing portion 110 is not present on the first surface 130, which has a larger area. Therefore, even if another energy storage device 10 is placed on the first surface 130, the other energy storage device 10 will not tilt. As a result, the energy storage device 10 can suppress unevenness in the distribution of pressure applied to the lower energy storage device 10 when multiple energy storage devices 10 are stacked. Furthermore, when used in an all-solid-state battery, high pressure must be applied uniformly from the outer surface of the battery to maximize battery performance, and therefore the packaging form of the present invention is preferable. Furthermore, in the energy storage device 10, the base portion of the first sealing portion 110 is located 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 on the second surface 140.

[0065] 2. Second Embodiment In the electricity storage device 10 according to the first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the surfaces of the exterior member 101 that face each other. However, the shape and method of forming the second sealed portion 120 are not limited to this. The following description will focus on the parts that are different from the first embodiment, and a description of the parts that are common to the first embodiment will be omitted.

[0066] <2-1. Configuration of the energy storage device> Fig. 9 is a plan view schematically showing an electricity storage device 10X according to the second embodiment. Fig. 10 is a side view schematically showing an electricity storage device 10X. Fig. 11 is a perspective view schematically 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 the electrode assembly 200. With the lid body 400 fitted, 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 tray-like member with a bottom that is rectangular 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 member 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 member 100X. In the power storage device 10X, the bottom side of the lid body 400 may be located outside the exterior member 100X.

[0069] Furthermore, 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. Note that in the power storage device 10X, the position from which 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 in 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 integrally formed.

[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 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 in any one of the six surfaces 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. Method of manufacturing 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 heat-seals the surfaces (thermal adhesive resin layers) of the exterior member 101 that face each other to form the first sealed portion 110 (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 assembly 200 in the unfinished product produced in step S220 and attaches lid bodies 400 to 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, which has a smaller area. Therefore, with 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 toward the second surface 140 having a smaller area. For example, the first sealing unit 110 may be bent toward the first surface 130 having a larger area. Furthermore, the base portion of the first sealing unit 110 does not necessarily have to be on the side 135 of the exterior body 100X. The base 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 (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 assembly 200 is sealed by the lid 400. That is, the second sealed portion 120X is formed in the portion where the lid 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 400.

[0081] Furthermore, in the electricity storage device 10X, an excessive load caused by the corner C1 (FIGS. 9 and 10) of the electrode body 200 piercing the exterior member 101 is not generated at a position of the exterior member 101 that covers the corner C1. This is because, as described above, in the electricity storage device 10X, the second sealed portion 120X is not formed by heat-sealing the mutually facing surfaces of the exterior member 101 as in the first embodiment.

[0082] Furthermore, the manufacturing procedure for 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 for the electricity storage device 10X according to the second embodiment. The steps shown in FIG. 15 are performed, for example, by a manufacturing apparatus for the electricity storage device 10X. The manufacturing apparatus attaches a member (for example, the 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. The manufacturing apparatus then 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 surfaces (thermally adhesive resin layers) of the exterior member 101 that face each other, 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 electricity storage device 10X. The electricity storage device 10X may be manufactured by such a procedure.

[0084] 3. Third Embodiment In a battery manufacturing process, a temporarily sealed electricity storage device typically undergoes a step of aging for a predetermined time in a predetermined temperature environment (hereinafter referred to as the aging step) for the purpose of allowing an electrolyte to penetrate into the electrode body. During the aging step, gas is generated from the electrode body 200, and it becomes necessary to discharge the gas to the outside of the battery. In the electricity storage device 10X according to the second embodiment, a mechanism for releasing the gas generated in the aging step in the final stage of manufacturing the electricity storage device 10X is not provided. In the electricity storage device 10Y according to the third embodiment, a mechanism for releasing the gas generated from the electrode body 200 in the final stage of manufacturing the electricity storage device 10Y is provided. 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.

[0085] <3-1. Configuration of the energy 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 the lid body 400 is attached to the exterior member 101Y during the manufacture of the electricity storage device 10Y.

[0086] 16 and 17, a piece 150 is formed when the exterior member 101Y is wrapped around the electrode body 200. The piece 150 is formed by joining mutually facing surfaces of the exterior member 101Y when the exterior member 101Y is wrapped around the electrode body 200. More specifically, the piece 150 is formed by joining (heat sealing) the peripheral edges of the surfaces that face each other when the exterior member 101Y is wrapped around the electrode body 200. That is, a first sealed portion 154 is formed on the peripheral edge of the piece 150.

[0087] Furthermore, in the piece 150, spaces 152 are formed where the opposing surfaces of the exterior member 101Y are not joined. In the vicinity of the side 135, joined regions 151 where the opposing surfaces of the exterior member 101Y are joined and unjoined regions 153 where the opposing surfaces of the exterior member 101Y are not joined are arranged alternately. That is, in the piece 150, a pattern of joined regions 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 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, near side 135, regions where the bonding strength between the opposing surfaces of the exterior member 101Y is strong and regions where the bonding strength between the surfaces is weak are alternately arranged along side 135. In other words, in the heat-sealed portion near side 135, thin portions and thick portions are alternately arranged along side 135. This is because, by heat-sealing the vicinity of side 135 again, the unbonded region 153 is single-sealed, but the bonded region 151 is double-sealed.

[0090] <3-2. Method of manufacturing electricity storage devices> 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 opposing surfaces (thermally adhesive resin layers) of the exterior member 101Y (step S310). The manufacturing equipment forms the pattern of the bonding region 151 by heat-sealing the opposing surfaces of the exterior member 101Y near the side 135 (step S320).

[0092] The manufacturing equipment attaches lid bodies 400 to the openings at both ends with the electrode assembly 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 step by, for example, cutting off piece 150 (step S350). The manufacturing equipment heat-seals a portion of piece 150 including bonding region 151 into a strip shape and removes the edge portion to reseal exterior body 100Y (step S360). Thereafter, piece 150 is folded toward second surface 140, thereby completing 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, the packaging form of the present invention is preferred because it is necessary to apply high pressure uniformly from the outer surface of the battery to exhibit battery performance.

[0095] 4. Embodiment 4 In the power storage device 10X according to the second embodiment, the position from which the electrode terminal 300 protrudes to the outside is between the lid 400 and the exterior member 101. However, the position from which the electrode terminal 300 protrudes to the outside is not limited to this. 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 energy storage device> FIG. 19 is a plan view schematically showing an electricity storage device 10XA according to the fourth embodiment. FIG. 20 is a side view schematically showing the electricity storage device 10XA. An exterior body 100X of the electricity storage device 10XA includes, in a plan view, a pair of long sides 100XA and a pair of short sides 100XB. The exterior body 100X is formed by fitting a lid body 400 into each of openings along the long sides 100XA of an exterior member 101 wrapped around the electrode assembly 200. With the lid body 400 fitted, 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. 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 sides 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, and therefore larger electrode terminals 300 can be used, making it possible to provide a high-output power storage device 10XA.

[0099] [5. Modifications] Although the first to fourth embodiments have been described above, the present invention is not limited to the first to fourth embodiments, 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-described embodiments 1-4, one exterior member is wrapped around the electrode assembly 200. However, it is not necessary to wrap one exterior member around the electrode assembly 200. For example, two or more exterior members may be wrapped around the electrode assembly 200.

[0101] FIG. 21 is a side view showing the state in which exterior members 101Z1 and 101Z2 are wrapped around the electrode assembly 200 during the manufacturing process of an electric storage device according to a modified example. As shown in FIG. 21, the electrode assembly 200 is surrounded by 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 bent toward the second surface 140Z, not toward the first surface 130Z. Even with this configuration, it is possible to suppress 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, the packaging form of the present invention is preferable because high pressure must be applied uniformly from the outer surface of the battery to maximize battery performance. Note that in this example, each first sealing portion 110Z does not necessarily need to be bent. In this modified example, each sealing portion 110Z may seal while sandwiching a part of the electrode terminal 300. Furthermore, in this modified example, 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> Furthermore, in the above-described embodiments 1-4, the electrode assembly 200 is a so-called stack type configured by stacking a plurality of electrodes 210, but the form of the electrode assembly 200 is not limited to this. The electrode assembly 200 may be, for example, a so-called wound type configured by winding a positive electrode and a negative electrode with a separator interposed therebetween. Furthermore, the electrode assembly 200 may be configured by stacking a plurality of so-called wound type electrode assemblies.

[0103] <5-3> Furthermore, in the above-described embodiments 1-4, the second surface 140 is a flat surface that extends downward from the first surface 130 at a substantially right angle. However, the shape 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 with flat and curved surfaces formed on the outer periphery. Here, assume that the area of ​​the flat surface is larger than the area of ​​the curved surface, and the first surface 130 covers the flat 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 where the second surface 140 extends downward from the first surface 130 is the edge 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> Furthermore, in the first embodiment, the electrode terminal 300 is disposed in the second sealing portion 120. However, the position at which the electrode terminal 300 is disposed in the exterior body 100 is not limited to this. 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 with the electrode terminal 300 sandwiched between them. In this modification, at least one of the two electrode terminals 300 may be bent toward the second surface 140, bent away from the second surface 140, or not bent 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, thereby improving the hermeticity of the exterior body 100. Furthermore, the electrode assembly 200 can be easily housed in the exterior body 100. In this modification, for example, a cover 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, the exterior member 101 and the lid 400 are heat-sealed together to form the second sealed portion 120.

[0106] <5-6> Furthermore, in the second embodiment, the configuration of the lid 400 can be modified as desired. FIG. 23 is a perspective view showing a lid 500 that is a modified version of the lid 400. The lid 500 is, for example, plate-shaped and includes a first surface 500A that faces the electrode assembly 200 (see FIG. 9) and a second surface 500B opposite the first surface 500A. A hole 500C that penetrates the first surface 500A and the second surface 500B is formed in the center of the lid 500. The lid 500 is made of, for example, resin. In this modified version, an adhesive film 530 that adheres to both the electrode terminal 300 and the lid 500 is preferably attached to a predetermined area of ​​the electrode terminal 300 that includes a portion that is joined to the lid 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 by joining the first portion 510 and the second portion 520 so as to sandwich the electrode terminal 300 and the adhesive film 530. Alternatively, the lid 500 may be manufactured by insert molding the lid 500 onto the electrode terminal 300 to which the adhesive film 530 is attached. In this modification, a barrier layer is preferably laminated on at least a portion of the surface of the lid 500. Alternatively, if the lid 500 has multiple layers, a barrier layer may be formed on any of the layers. The barrier layer may be made of aluminum, for example. In this modification, if 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, with the lid 500 fitted, the second sealing portion 120X is formed by joining the exterior member 101 and the second surface 500B of the lid 500. The joining means between the exterior member 101 and the second surface 500B of the lid 500 is, for example, heat sealing. In this modification, the exterior member 101 is joined to a wider area of ​​the lid 500, thereby improving the sealing performance of the exterior body 100X.

[0108] FIG. 25 is a front view of a lid body 600, which is another modification of the lid body 400 in the second embodiment. The lid body 600 includes a metal portion 610, which is a portion where metal is exposed on the surface, and the metal portion 610 is welded to the electrode 210 of the electrode body 200. The lid body 600 may be entirely formed of the metal portion 610, or the metal portion 610 may be partially formed. When the metal portion 610 is partially formed, the lid body 600 is formed of a multilayer material including a metal layer. When the lid body 600 is formed of a multilayer material with a metal layer as an intermediate layer, the metal portion 610 is a portion 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 portion 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. This allows the power storage device 10X (see FIG. 9) to be configured in a compact size.

[0109] FIG. 26 is a front view of a lid body 700 that is another modification of the lid body 400 in the second embodiment. The lid body 700 includes a metal portion 710 made of a metal material and a non-metal portion 720 that is 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 assembly 200. In the example shown in FIG. 26, the metal portion 710 of the lid body 700 functions as an electrode terminal, and therefore no space is required between the lid body 700 and the electrode 210. This allows the power storage device 10X (see FIG. 9) to be configured in a compact size.

[0110] <5-7> Furthermore, 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 to each other. However, the method of forming the second sealed portion 120 is not limited to this. FIG. 27 is a plan view schematically showing 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 second sealed portion 120Y is formed by heat-sealing the thermally adhesive resin layers of the protruding portion 101X to each other. 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, thereby improving the hermeticity of the exterior body 100. In this modification, the protruding portion 101X may be cut as necessary except for the portion 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: electricity storage device, 100, 100X, 100Y: exterior body, 101, 101Y, 101Z1, 101Z2: exterior member, 101X: protrusion, 110, 110Z, 154: first sealing portion, 120, 120X, 120Y: second sealing portion, 130, 130Z: first surface, 135, 135Z: edge, 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: cover, 610, 710: metal part, C1 corner.

Claims

1. The electrode body; an electrode terminal connected to the electrode body; an exterior body that seals the electrode body, The exterior body is a film-like exterior member that wraps the electrode body; a lid that seals the electrode assembly together with the exterior member; a first sealing portion formed by joining surfaces of the exterior member facing 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 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, The electrode terminal passes between the lid and the exterior member and protrudes to the outside of the exterior member. Energy storage device.

2. The lid includes a barrier layer. The electricity storage device according to claim 1 .

3. an adhesive film that adheres to the electrode terminal and the lid; the adhesive film is attached to at least a portion of the electrode terminal that is to be joined to the lid; The electrode terminal and the lid are joined via the adhesive film. The electricity storage device according to claim 1 or 2.

4. The first sealing portion is bent so as to contact the second surface. The electricity storage device according to claim 1 or 2.

5. The first sealing portion covers substantially the entire second surface in a state where the first sealing portion is bent so as to contact the second surface. The electricity storage device according to claim 4 .

Images