Electricity storage device, heat transfer body, and packaging body

Abstract

To provide a power storage device, a heat transfer body, and a packaging body capable of more suitably suppressing a temperature rise of an electrode body.SOLUTION: A power storage device includes: an electrode body; an exterior body including an exterior film for sealing the electrode body; and a heat transfer body attached to at least part of a surface of the exterior body. The exterior film includes at least a base material layer, an exterior barrier layer, and a heat fusible resin layer. The exterior barrier layer is composed of a material containing a metal. The heat transfer body includes a heat transfer layer composed of a material containing a metal. Thickness of the heat transfer layer is equal to or larger than that of the exterior barrier layer.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a power storage device, a heat transfer body, and a packaging body.

Background Art

[0002] Patent Document 1 discloses an example of a power storage device. In this power storage device, an electrode body is sealed in a bag body formed of a laminate film. The laminate film includes a water vapor impermeable layer formed of a material containing a metal such as aluminum. Therefore, the intrusion of water vapor and the like into the bag body is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above power storage device, when the electrode body generates heat, part of the heat is transmitted to the metal constituting the water vapor impermeable layer and dissipated to the outside. Therefore, an excessive increase in the temperature of the electrode body is suppressed. From the viewpoint of more preferably suppressing the temperature rise of the electrode body, it is conceivable to increase the thickness of the water vapor impermeable layer. However, since the water vapor impermeable layer is formed of a material containing a metal, if the thickness of the water vapor impermeable layer is increased, the productivity of the laminate film may decrease.

[0005] An object of the present invention is to provide a power storage device, a heat transfer body, and a packaging body that can more preferably suppress an excessive increase in the temperature of an electrode body.

Means for Solving the Problems

[0006] A first aspect of the present invention relates to an energy storage device comprising an electrode body, an outer casing including an outer film that seals the electrode body, and a heat transfer element attached to at least a portion of the surface of the outer casing, wherein the outer casing film has at least a base layer, an outer barrier layer, and a heat-sealable resin layer, the outer barrier layer is made of a material containing metal, and the heat transfer element includes a heat transfer layer made of a material containing metal, the thickness of the heat transfer layer being greater than or equal to the thickness of the outer barrier layer.

[0007] A second aspect of the present invention relates to a first aspect of an energy storage device, wherein the outer casing includes a first surface and a second surface having a larger area than the first surface, and the heat transfer element is attached to at least the second surface.

[0008] A third aspect of the present invention relates to a power storage device according to the first or second aspect, wherein the heat transfer element is configured in the form of a cover.

[0009] A fourth aspect of the present invention is an energy storage device according to any one of the first to third aspects, wherein the casing includes a cooling surface that is cooled by a cooling mechanism, and the heat transfer element is attached to at least a portion of the surface of the casing other than the cooling surface such that the cooling surface is exposed.

[0010] A fifth aspect of the present invention is an energy storage device relating to any one of the first to fourth aspects, wherein the thickness of the outer barrier layer is 100 μm or less.

[0011] A sixth aspect of the present invention relates to a power storage device relating to any one of the first to fifth aspects, wherein the heat transfer element includes a base layer laminated on the heat transfer layer.

[0012] A seventh aspect of the present invention relates to an energy storage device comprising an electrode body, an outer casing including an outer film that seals the electrode body, and a heat transfer element attached to the outer casing such that at least a portion of the surface of the outer casing is exposed, wherein the outer casing film has at least a base layer, an outer barrier layer, and a heat-sealable resin layer, the outer barrier layer is made of a material containing metal, and the heat transfer element includes a heat transfer layer made of a material containing metal.

[0013] A heat transfer element according to the eighth aspect of the present invention is a heat transfer element attached to the surface of an outer casing in an energy storage device comprising an electrode body and an outer casing including an outer film that seals the electrode body, wherein the heat transfer element includes a heat transfer layer made of a material including a metal.

[0014] A heat transfer body according to the ninth aspect of the present invention is a heat transfer body according to the eighth aspect, wherein the outer film includes an outer barrier layer made of a material containing metal, and the thickness of the heat transfer layer is greater than or equal to the thickness of the outer barrier layer.

[0015] A heat transfer body according to the tenth aspect of the present invention is a heat transfer body according to the ninth aspect, wherein the outer casing includes a first surface and a second surface having a larger area than the first surface, and is attached to at least the second surface.

[0016] A heat transfer body according to the 11th aspect of the present invention is a heat transfer body according to any one of the 8th to 10th aspects, and is configured in the form of a cover.

[0017] A heat transfer body according to the twelfth aspect of the present invention is a heat transfer body according to any one of the eighth to eleventh aspects, wherein the outer casing includes a cooling surface that is cooled by a cooling mechanism, and the heat transfer body is attached to at least a portion of the surface of the outer casing other than the cooling surface such that the cooling surface is exposed.

[0018] A heat transfer body according to the 13th aspect of the present invention is a heat transfer body according to any one of the 10th to 12th aspects, which reference the 9th aspect, wherein the thickness of the outer barrier layer is 100 μm or less.

[0019] The heat transfer body according to the 14th aspect of the present invention is the heat transfer body according to any one of the 8th to 13th aspects, and the heat transfer body includes a base material layer laminated on the heat transfer layer.

[0020] The package according to the 15th aspect of the present invention includes an outer packaging film for sealing an electrode body, and a heat transfer body attached to at least a part of the surface of the outer packaging film. The outer packaging film has at least a base material layer, an outer barrier layer, and a heat-sealable resin layer. The outer barrier layer is composed of a material containing metal, and the heat transfer body includes a heat transfer layer composed of a material containing metal, and the thickness of the heat transfer layer is equal to or greater than the thickness of the outer barrier layer.

[0021] The package according to the 16th aspect of the present invention includes an outer packaging film for sealing an electrode body, and a heat transfer body attached to the surface of the outer packaging film so that at least a part of the surface of the outer packaging film is exposed. The outer packaging film has at least a base material layer, an outer barrier layer, and a heat-sealable resin layer. The outer barrier layer is composed of a material containing metal, and the heat transfer body includes a heat transfer layer composed of a material containing metal.

Advantages of the Invention

[0022] According to the power storage device, heat transfer body, and package of the present invention, it is possible to more preferably suppress the excessive rise in the temperature of the electrode body.

Brief Description of the Drawings

[0023] [Figure 1] Front view of the power storage device and cooling mechanism of the embodiment. [Figure 2] Cross-sectional view showing the layer structure of the outer packaging film of the power storage device in FIG. 1. [Figure 3] Exploded perspective view of the power storage device in FIG. 1. [Figure 4] Cross-sectional view showing the layer structure of the heat transfer body of the power storage device in FIG. 1. [Figure 5] Cross-sectional view showing the structure of the cooling mechanism in FIG. 1. [Figure 6] A plan view showing an example of packaging. [Figure 7] A table showing the specifications of the energy storage device in the example and the test results. [Modes for carrying out the invention]

[0024] A device for storing energy according to one embodiment of the present invention will be described below with reference to the drawings. In this specification, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation 2~15mm means 2mm or more and 15mm or less.

[0025] <1. Overall configuration of the energy storage device> Figure 1 is a front view of the energy storage device 10 and the cooling mechanism 100 for cooling the energy storage device 10 according to this embodiment. Multiple energy storage devices 10 are used, for example, arranged in a row on the cooling mechanism 100. Multiple energy storage devices 10 are arranged so that there is a predetermined space between adjacent energy storage devices 10. The energy storage device 10 includes an electrode body 20, an outer casing 30, electrode terminals 50, and a heat transfer body 60.

[0026] The electrode body 20 includes electrodes (positive and negative electrodes) and separators that constitute an energy storage component such as a lithium-ion battery, capacitor, or all-solid-state battery. The shape of the electrode body 20 is approximately a rectangular parallelepiped. Note that "approximately a rectangular parallelepiped" includes not only a perfect rectangular parallelepiped but also a three-dimensional object that can be considered a rectangular parallelepiped by modifying the shape of a part of its outer surface, for example.

[0027] The electrode terminal 50 is a metal terminal used for power input and output in the electrode body 20. One end of the electrode terminal 50 is electrically connected to an electrode (positive or negative electrode) included in the electrode body 20, and the other end protrudes outward from the edge of the outer casing 30.

[0028] The metal materials that make up the electrode terminals 50 are, for example, aluminum, nickel, copper, etc. For example, if the electrode body 20 is a lithium-ion battery, the electrode terminals 50 connected to the positive electrode are usually made of aluminum, etc., and the electrode terminals 50 connected to the negative electrode are usually made of copper, nickel, etc.

[0029] The outer casing 30 is composed of an outer film 40 (Figure 4, etc.) and seals the electrode body 20. The method of sealing the electrode body 20 with the outer film 40 can be arbitrarily selected. For example, a housing portion (recess) for accommodating the electrode body 20 may be formed in at least one of the two outer films 40 by cold forming, and after accommodating the electrode body 20 in the recess, the electrode body 20 may be sealed by heat sealing along the outer circumference of the outer film 40 in a plan view. In another example, the electrode body 20 may be sealed by wrapping the outer film 40 around the electrode body 20 and sealing the open portion. According to another example, the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. In order to reduce the dead space between the electrode body 20 and the outer film 40 in order to improve the volumetric energy density of the energy storage device 10, it is preferable that the outer film 40 is in direct or indirect contact with the electrode body 20. Furthermore, in all-solid-state batteries, it is necessary to eliminate the space between the electrode body 20 and the outer film 40, as it is required to apply high pressure uniformly from the outside of the battery in order to achieve battery performance. Therefore, it is preferable that the outer film 40 is in direct or indirect contact with the electrode body 20. The state in which the outer film 40 is in direct or indirect contact with the electrode body 20 includes, for example, a state in which the outer film 40 is in contact with the separator, current collector foil, electrode material, or insulating material that constitutes the electrode body 20.

[0030] <2. Outer film composition> Figure 2 is a cross-sectional view showing an example of the layer structure of the outer film 40. The outer film 40 is a laminate (laminate film) having, for example, a base layer 41, an outer barrier layer 42, and a heat-sealable resin layer 43 in that order. The outer film 40 only needs to include at least an outer barrier layer 42. It is preferable that the outer film 40 is heat-sealable.

[0031] The base layer 41 is a layer that imparts heat resistance to the outer film 40 and suppresses the occurrence of pinholes that may occur during processing or distribution. The base layer 41 is composed of, for example, at least one stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one stretched polyester resin layer and a stretched polyamide resin layer in the base layer 41, the outer barrier layer 42 can be protected during processing of the outer film 40, and the breakage of the outer film 40 can be suppressed. Furthermore, from the viewpoint of increasing the tensile elongation of the outer film 40, the stretched polyester resin layer is preferably a biaxially oriented polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially oriented polyamide resin layer. Moreover, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially oriented polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially oriented nylon (ONy) film. The base layer 41 may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 41 is preferably, for example, 5 to 300 μm, and more preferably 20 to 150 μm, from the viewpoint of film strength.

[0032] The outer barrier layer 42 is made of a material containing a metal. Examples of metals include aluminum alloy, stainless steel, titanium steel, and steel plate. In this embodiment, it is preferable that the outer barrier layer 42 is made of a material containing an aluminum alloy or stainless steel. Aluminum alloys are excellent in terms of moisture resistance, workability such as ductility, and cost. The material constituting the outer barrier layer 42 preferably contains iron from the viewpoint of packaging suitability and pinhole resistance when packaging the electrode body 20. The iron content in the material constituting the outer barrier layer 42 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 provides packaging suitability, excellent pinhole resistance, and ductility of the outer film 40. An iron content of 5.0 mass% or less provides excellent flexibility of the outer film 40.

[0033] The thickness of the outer barrier layer 42 is preferably 15 μm or more, and more preferably 30 μm or more, from the viewpoint of barrier properties, pinhole resistance, and packaging suitability. The thickness of the outer barrier layer 42 is preferably 100 μm or less, more preferably 90 μm or less, more preferably 85 μm or less, and even more preferably 80 μm or less. Preferred ranges for the thickness of the outer barrier layer 42 are, for example, 15 μm to 100 μm, 15 μm to 90 μm, 15 μm to 85 μm, 15 μm to 80 μm, 30 μm to 100 μm, 30 μm to 90 μm, 30 μm to 85 μm, and 30 μm to 80 μm. By having an outer barrier layer 42 thickness of 15 μm or more, the outer film 40 becomes less likely to break even when stress is applied during packaging. By having an outer barrier layer 42 with a thickness of 100 μm or less, the mass increase of the outer film 40 can be reduced, and the decrease in the gravimetric energy density of the energy storage device 10 can be suppressed.

[0034] Furthermore, since the outer barrier layer 42 is made of a material containing metal, it is preferable that the outer film 40 has a corrosion-resistant coating on at least the side opposite to the base layer 41 in order to prevent dissolution and corrosion. The outer barrier layer 42 may have a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the outer barrier layer 42 by performing corrosion prevention treatments on the surface of the outer barrier layer 42, such as hot water modification treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or coating agent application. Specifically, the corrosion-resistant coating means a coating that improves the acid resistance of the outer barrier layer 42 (acid-resistant coating), a coating that improves the alkali resistance of the outer barrier layer 42 (alkali-resistant coating), etc. One type of treatment may be performed to form the corrosion-resistant coating, or two or more types may be combined. In addition, it is possible to have multiple layers instead of just one layer. Furthermore, among these treatments, hydrothermal modification and anodizing are processes that dissolve the surface of the metal foil 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, if the outer barrier layer 42 has a corrosion-resistant coating, the outer barrier layer 42 includes the corrosion-resistant coating.

[0035] The corrosion-resistant coating prevents delamination between the outer barrier layer 42 and the base layer 41 during the molding of the outer film 40, prevents dissolution and corrosion of the surface of the outer barrier layer 42 due to hydrogen fluoride generated by the reaction of electrolyte and water, prevents dissolution and corrosion of aluminum oxide present on the surface of the outer barrier layer 42, improves the adhesion (wettability) of the surface of the outer barrier layer 42, and exhibits the effect of preventing delamination between the base layer 41 and the outer barrier layer 42 during heat sealing and during molding.

[0036] The heat-sealable resin layer 43 is a layer that provides heat-sealing properties to the outer film 40. Examples of the heat-sealable resin layer 43 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. The heat-sealable resin layer 43 may also be polybutylene terephthalate. The thickness of the heat-sealable resin layer 43 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm, from the viewpoint of sealing properties and strength.

[0037] <3. Exterior Structure> Figure 3 is an exploded perspective view of the energy storage device 10. Note that the electrode body 20 is not shown in Figure 3. The outer casing 30 includes a first surface 31, a pair of second surfaces 32A and 32B, a third surface 33, and a pair of fourth surfaces 34A and 34B. The shapes of the first surface 31 to the fourth surfaces 34A and 34B are determined according to the shape of the electrode body 20. In this embodiment, the shapes of the first surface 31 to the fourth surfaces 34A and 34B are rectangular.

[0038] The first surface 31 is the upper surface when the energy storage device 10 is mounted on the cooling mechanism 100. The pair of second surfaces 32A and 32B face each other via the electrode body 20. The area of ​​each of the pair of second surfaces 32A and 32B is larger than that of the first surface 31. The third surface 33 is the lower surface when the energy storage device 10 is mounted on the cooling mechanism 100, in other words, the surface that is cooled by the cooling mechanism 100. Hereinafter, the third surface 33 may be referred to as the cooling surface 33. In this embodiment, the area of ​​the cooling surface 33 is equal to the area of ​​the first surface 31. The pair of fourth surfaces 34A and 34B are the surfaces through which the electrode terminals 50 pass. The pair of fourth surfaces 34A and 34B face each other via the electrode body 20. In this embodiment, the area of ​​the pair of fourth surfaces 34A and 34B is smaller than that of the first surface 31 and the cooling surface 33.

[0039] <4. Heat Transfer Element Configuration> Figure 4 is a cross-sectional view showing an example of the layer configuration of the heat transfer element 60. The heat transfer element 60 is attached to the surface of the outer casing 30, in other words, to at least a portion of the surface of the base layer 41 of the outer film 40. The heat transfer element 60 is attached to the outer film 40 after, for example, the electrode body 20 has been sealed by cold forming, or after the electrode body 20 has been sealed by wrapping the outer film 40 around the electrode body 20. In another example, a package 70 (see Figure 6) is manufactured in which the heat transfer element 60 is pre-bonded to at least a portion of the surface of the outer film 40. In a preferred example, a package 70 is manufactured in which the heat transfer element 60 is pre-bonded to the surface of the outer film 40 such that at least a portion of the surface of the outer film 40 is exposed. The shape of the package 70 may be a shape in which a housing portion (recess) for housing the electrode body 20 is formed by cold forming, or it may be a sheet shape. If the package 70 has a shape with a housing portion, the electrode body 20 is housed in the housing portion of the package 70, and the package 70 is sealed. If the packaging 70 is in the form of a sheet, the electrode body 20 is sealed by wrapping it around the packaging 70. The heat transfer body 60 is, for example, a laminate (laminate film) having a base layer 60A, a heat transfer layer 60B, and an innermost layer 60C in that order. The heat transfer body 60 may also be a single layer consisting of at least the heat transfer layer 60B. That is, the heat transfer body 60 can omit at least one of the base layer 60A and the innermost layer 60C. The base layer 60A is laminated, for example, when insulation is required. The innermost layer 60C is laminated to bond with the outer film 40. The innermost layer 60C may be, for example, an adhesive layer.

[0040] The material constituting the base layer 60A can be the same as the material exemplified in the base layer 41 of the outer film 40. In this embodiment, the material constituting the base layer 60A is polyethylene terephthalate.

[0041] The innermost layer 60C is preferably made of a material that can be heat-sealed to the base layer 41 of the outer film 40, in other words, it is preferably a heat-sealable resin layer. When the innermost layer 60C is a heat-sealable resin layer, the material constituting the innermost layer 60C can be the same as the material exemplified for the heat-sealable resin layer 43 of the outer film 40. In this embodiment, the material constituting the innermost layer 60C is polypropylene. The material constituting the innermost layer 60C may be, for example, an olefin resin other than polypropylene, or polybutylene terephthalate. When the innermost layer 60C is not a heat-sealable resin layer, the material constituting the innermost layer 60C may be, for example, an adhesive such as urethane resin, or a tack, and may be made of any material that can be joined to the base layer 41 of the outer film 40 via double-sided tape or the like. An example of an adhesive is urethane resin.

[0042] The heat transfer layer 60B may be made of a material containing metal, similar to the outer barrier layer 42. From the viewpoint of thermal conductivity, examples of metals include aluminum alloy, copper, gold, silver, brass, iron, and stainless steel. In this embodiment, from the viewpoint of thermal conductivity and cost, the heat transfer layer 60B is preferably made of a material containing aluminum alloy or copper. The material constituting the heat transfer layer 60B and preferred configuration are the same as for the outer barrier layer 42, but in order to suitably transfer the heat generated from the electrode body 20 to the cooling mechanism 100, the thickness of the heat transfer layer 60B is preferably greater than or equal to the thickness of the outer barrier layer 42. The thickness of the heat transfer layer 60B is preferably 15 μm or more, and more preferably 30 μm or more. From the viewpoint of the moldability and productivity of the heat transfer body 60, the thickness of the heat transfer layer 60B is preferably 100 μm or less, more preferably 90 μm or less, more preferably 85 μm or less, and more preferably 80 μm or less. The preferred thickness range for the heat transfer layer 60B is, for example, 15 μm to 100 μm, 15 μm to 90 μm, 15 μm to 85 μm, 15 μm to 80 μm, 30 μm to 100 μm, 30 μm to 90 μm, 30 μm to 85 μm, and 30 μm to 80 μm. A thickness of 15 μm or more for the heat transfer layer 60B allows for efficient transfer of heat generated from the electrode body 20 to the cooling mechanism 100. A thickness of 100 μm or less for the heat transfer layer 60B improves the moldability and productivity of the heat transfer body 60. From the viewpoint of efficiently transferring heat generated in the electrode body 20 to the cooling mechanism 100, it is preferable for the heat transfer layer 60B to be as thick as possible. For this reason, if the sheet-shaped heat transfer body 60 is not molded, in other words, if no bending or other processing is performed, the thickness of the heat transfer layer 60B is preferably 300 μm or less.

[0043] When the electrode body 20 generates heat, some of that heat is transferred to the first to fourth surfaces 31 to 34A and 34B of the outer casing 30. In order to suitably transfer the heat from the electrode body 20 to the cooling mechanism 100, it is preferable that the heat transfer element 60 be attached to at least the pair of second surfaces 32A and 32B of the outer casing 30, which have a large surface area. On the other hand, in the operating state of the energy storage device 10, the cooling surface 33 is in contact with the cooling mechanism 100 (see Figure 1), so it is preferable that the heat transferred to the cooling surface 33 is quickly transferred to the cooling mechanism 100. For this reason, it is preferable that the heat transfer element 60 is not attached to the cooling surface 33. In this embodiment, the heat transfer element 60 is attached to approximately the entire surface of the first surface 31 and the pair of second surfaces 32A and 32B.

[0044] The shape of the heat transfer element 60 can be arbitrarily selected as long as it can be attached to the surface of the outer casing 30. In this embodiment, the heat transfer element 60 is configured as a cover so that it can be easily attached to the outer casing 30. The heat transfer element 60 may not be formed as a cover but simply as a sheet. The heat transfer element 60 has a shape similar to a U, including a first part 61 and a pair of second parts 62A and 62B. The first part 61 is attached to the first surface 31 of the outer casing 30. The shape of the first part 61 is the same as that of the first surface 31. The pair of second parts 62A and 62B are connected to the first part 61. The pair of second parts 62A and 62B are attached to a pair of second surfaces 32A and 32B of the outer casing 30. The second part 62A is attached to the second surface 32A of the outer casing 30. The shape of the second part 62A is the same as that of the second surface 32A. The second part 62B is attached to the second surface 32B of the outer casing 30. The shape of the second part 62B is the same as the shape of the second surface 32B.

[0045] <5. Cooling Mechanism Configuration> Figure 5 is a cross-sectional view showing an example of the cooling mechanism 100. The specific configuration of the cooling mechanism 100 can be any known cooling mechanism, such as a water-cooled cooling mechanism or an air-cooled cooling mechanism, as long as it can cool the energy storage device 10. In this embodiment, the cooling mechanism 100 is a water-cooled cooling mechanism including a support layer 110, a first metal layer 120, and a second metal layer 130. The support layer 110 is a layer on which the energy storage device 10 is placed. The material constituting the support layer 110 is, for example, a high thermal conductivity gel. The first metal layer 120 is joined to the support layer 110. The material constituting the first metal layer 120 is, for example, aluminum. The second metal layer 130 is joined to the first metal layer 120 such that a water channel 140 is formed between it and the first metal layer 120. The material constituting the second metal layer 130 is, for example, aluminum. The temperature of the water flowing through the channel 140 can be arbitrarily selected as long as it is at a temperature that can cool the energy storage device 10, but is preferably 60°C or lower, and more preferably 30°C or lower.

[0046] <6. Function and Effects of Energy Storage Devices> In the energy storage device of this embodiment, the outer film 40 including the outer barrier layer 42 and the heat transfer element 60 including the heat transfer layer 60B are made of separate components, so that the individual thicknesses of the outer film 40 and the heat transfer element 60 do not increase. As a result, the outer film 40 and the heat transfer element 60 can be produced efficiently. Furthermore, when the electrode body 20 generates heat, that heat is transferred to the cooling mechanism 100 via the first heat transfer route, the second heat transfer route, the third heat transfer route, and the fourth heat transfer route.

[0047] The first heat transfer route is a route through the third surface 33 of the outer casing 30, in the order of the lamination direction of the outer film 40, that is, through the heat-fusible resin layer 43 of the outer film 40, the outer barrier layer 42, the base material layer 41, and the cooling mechanism 100. For this reason, when considering the first heat transfer route, it is preferable that the thickness of the outer film 40 be thin.

[0048] The second heat transfer route is a route through which heat is transferred from the outer barrier layer 42 to the cooling mechanism 100 and from the base layer 41 to the cooling mechanism 100, after the heat has been transferred to the heat-fusible resin layer 43 and outer barrier layer 42 of the outer film 40. If heat conduction is slow in the second heat transfer route, some of the heat is transferred to the heat transfer element 60 and then moves to the fourth heat transfer route. Since the heat transfer element 60 has the function of assisting heat transfer by the second heat transfer route, heat conduction in the planar direction, which is perpendicular to the lamination direction, is important. For this reason, it is preferable that the thickness of the heat transfer layer 60B of the heat transfer element 60 be as thick as possible.

[0049] The third heat transfer route is a route through which heat is transferred in the following order: the heat-fusible resin layer 43 of the outer film 40, the outer barrier layer 42, the base material layer 41, the innermost layer 60C of the heat transfer body 60, the heat transfer layer 60B, and the cooling mechanism 100.

[0050] The fourth heat transfer route is a route through which heat is transferred in the following order: the heat-fusible resin layer 43 of the outer film 40, the outer barrier layer 42, the base material layer 41, the innermost layer 60C of the heat transfer element 60, the heat transfer layer 60B, the innermost layer 60C, the base material layer 41, the outer barrier layer 42, the base material layer 41, and the cooling mechanism 100.

[0051] Since the energy storage device 10 is equipped with a heat transfer element 60, heat transfer proceeds not only through the first and second heat transfer routes but also through the third and fourth heat transfer routes, thus effectively suppressing an excessive rise in the temperature of the energy storage device 10. Furthermore, the energy storage device 10 provides the following additional benefits.

[0052] <6-1> Since the thickness of the heat transfer layer 60B is greater than or equal to the thickness of the outer barrier layer 42, heat can be suitably transferred to the cooling mechanism 100 via the heat transfer element 60 in the third heat transfer route and the fourth heat transfer route.

[0053] <6-2> The heat transfer element 60 is attached to at least the second surface 32A and 32B of the outer casing 30, which have a relatively large surface area. This allows the heat generated from the electrode body 20 to be more effectively transferred to the cooling mechanism 100.

[0054] <6-3> Since the heat transfer element 60 is configured in a cover-like shape, the heat transfer element 60 can be easily attached to the outer casing 30.

[0055] <6-4> Since no heat transfer element 60 is attached to the cooling surface 33, the heat transferred to the cooling surface 33 can be quickly transferred to the cooling mechanism 100.

[0056] <6-5> Since the thickness of the outer barrier layer 42 is 100 μm or less, the moldability and productivity of the heat transfer element 60 are good.

[0057] <7. Examples> The inventors of the present invention conducted a simulation test to confirm the relationship between the temperature of the energy storage device of the embodiment when no heat transfer element is attached and when a heat transfer element is attached. For the sake of convenience of explanation, in the following description, elements of the energy storage device of the embodiment that are the same as those in the embodiment will be denoted by the same reference numerals as in the embodiment.

[0058] Figure 7 is a table showing the specifications of the energy storage device 10 of the embodiment and the test results. In Figure 7, the numbers in parentheses next to the abbreviations for materials such as PET indicate the thickness of the layer. In addition, each layer constituting the outer film 40 and the heat transfer element 60 of the energy storage device 10 of the embodiment is joined together, for example, via an adhesive. In embodiments 1 to 3, when the heat transfer element 60 is attached to the outer casing 30, the heat transfer element 60 is attached to the entire first surface 31 and the pair of second surfaces 32A and 32B of the outer casing 30. That is, in embodiments 1 to 3, even when the heat transfer element 60 is attached, the heat transfer element 60 is not attached to the cooling surface 33 and the pair of fourth surfaces 34A and 34B. In embodiments 4 and 5, when the heat transfer element 60 is attached to the outer casing 30, the heat transfer element 60 is attached to the entire first surface 31 to the fourth surfaces 34A and 34B of the outer casing 30. In other words, in Examples 4 and 5, when the heat transfer element 60 is attached, the entire surface of the outer casing 30 is covered by the heat transfer element 60.

[0059] As shown in Figure 7, in Examples 1 to 5, it was confirmed that the temperature rise of the energy storage device 10 could be suppressed more effectively when the heat transfer element 60 was attached to the outer casing 30 than when the heat transfer element 60 was not attached. In Examples 3 and 4, the thickness of the outer barrier layer 42 of the outer film 40 and the thickness of the heat transfer layer 60B of the heat transfer element 60 were the same. In Example 5, the thickness of the outer barrier layer 42 of the outer film 40 was the same as in Examples 3 and 4, but the thickness of the heat transfer layer 60B of the heat transfer element 60 was thicker than in Examples 3 and 4. However, it was confirmed that Example 3 could suppress the temperature rise of the energy storage device 10 more effectively than Examples 4 and 5. This is thought to be because, in Example 3, the heat transfer element 60 was not attached to the cooling surface 33, so the heat transferred to the cooling surface 33 was quickly transferred to the cooling mechanism 100.

[0060] <8. Variation> The embodiments described above are illustrative of possible forms of the energy storage device, heat transfer element, and packaging according to the present invention, and are not intended to limit their forms. The energy storage device, heat transfer element, and packaging according to the present invention may take forms different from those illustrated in the embodiments. One example is a form in which some of the configurations of the embodiments are replaced, modified, or omitted, or a form in which new configurations are added to the embodiments. Several examples of modifications of the embodiments are shown below.

[0061] <8-1> The position on which the heat transfer element 60 is attached within the outer casing 30 can be arbitrarily selected. For example, the heat transfer element 60 may be attached to at least one of the pair of fourth surfaces 34A and 34B of the outer casing 30.

[0062] <8-2> In the above embodiment, the first portion 61 of the heat transfer element 60 and the pair of second portions 62A and 62B were connected, but the first portion 61 and at least one of the pair of second portions 62A and 62B may be separated.

[0063] <8-3> In the above embodiment, the heat transfer element 60 and the outer casing 30 were joined together. However, if the heat transfer element 60 is configured as a cover, the heat transfer element 60 and the outer casing 30 do not need to be joined together. Also, if the heat transfer element 60 is in sheet form, in other words, if the heat transfer element 60 is not molded, the heat transfer element 60 may be placed, for example, on the first surface 31 of the outer casing 30. In short, the heat transfer element 60 only needs to cover at least a part of the surface of the outer casing 30.

[0064] <8-4> In the above embodiment, the metal contained in the material constituting the outer barrier layer 42 and the metal contained in the material constituting the heat transfer layer 60B were aluminum. However, the metal contained in the material constituting the outer barrier layer 42 and the metal contained in the material constituting the heat transfer layer 60B may be different.

[0065] <8-5> In the above embodiment, the heat transfer element 60 may have one or more buffering layers (hereinafter referred to as "buffering layers") outside the heat transfer layer 60B. The buffering layers may be laminated on the outside of the base layer 60A, or the base layer 60A may also function as a buffering layer. If the heat transfer element 60 has multiple buffering layers, the multiple buffering layers may be adjacent to each other, or they may be laminated via the base layer 60A or the heat transfer layer 60B, etc.

[0066] The materials constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of cushioning materials include rubber, nonwoven fabric, or foamed sheet. Examples of rubber include natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably around 20 to 90. The materials constituting the nonwoven fabric are preferably materials with excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the buffer layer thickness is preferably 100 μm, more preferably 200 μm, and still more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the buffer layer thickness is preferably 5000 μm, and still more preferably 3000 μm. The preferred thickness ranges for the buffer layer are 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 most preferred thickness range for the buffer layer is 1000 μm to 3000 μm.

[0067] 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 still 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.

[0068] If the heat transfer element 60 has a buffer layer, the buffer layer acts as a cushion, thus preventing damage to the heat transfer element 60 from impact when the energy storage device 10 is dropped or from handling during the manufacturing of the energy storage device 10. In addition, when pressurization of the battery is required, such as in all-solid-state batteries, the pressure can be applied uniformly to the battery.

[0069] <8-6> In the above embodiment, the cooling mechanism 100 was a water-cooled cooling mechanism, but the configuration of the cooling mechanism 100 is not limited to this. For example, the cooling mechanism 100 may be an air-cooled cooling mechanism. In this modified example, the cooling surface 33 is in contact with air. [Explanation of Symbols]

[0070] 10: Energy storage devices 20: Electrode body 30: Exterior 31: 1st page 32A: 2nd side 32B: 2nd side 33: Third surface (cooling surface) 40: Exterior film 42: Exterior barrier layer 60: Heat transfer element 60A: Substrate layer 60B: Heat transfer layer 70: Packaging 100: Cooling mechanism

Claims

1. A packaging body for sealing an electrode assembly, Exterior film and A heat conductor that is attached in advance to at least a portion of the surface of the exterior film, The exterior film has at least a base layer, an exterior barrier layer, and a heat-sealable resin layer, the exterior barrier layer is made of a material containing a metal, The heat transfer body includes a heat transfer layer made of a material including a metal, The thickness of the heat transfer layer is equal to or greater than the thickness of the exterior barrier layer. packaging.

2. A packaging body for sealing an electrode assembly, Exterior film and A heat transfer body that is attached in advance to the surface of the exterior film so that at least a portion of the surface of the exterior film is exposed; The exterior film has at least a base layer, an exterior barrier layer, and a heat-sealable resin layer, the exterior barrier layer is made of a material containing a metal, The heat transfer body includes a heat transfer layer made of a material including a metal. packaging.

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