Battery

Abstract

This battery comprises: an electricity generation element having at least one unit cell including an electrode layer, a counter electrode layer, and an electrolyte layer positioned between the electrode layer and the counter electrode layer; and an insulating member that covers the electricity generation element. The insulating member is provided with: a first member that includes a first primary surface covering section that covers a first primary surface of the electricity generation element; and a second member that includes a second primary surface covering section that covers a second primary surface of the electricity generation element opposite to the first primary surface, the second member being joined to the first member. The joined section between the first member and the second member overlaps a side surface of the electricity generation element when viewed from a direction perpendicular to the side surface, and the elastic modulus of the first member is greater than the elastic modulus of the second member.

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Batteries including a power generating element formed by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are generally surrounded by a laminate film or insulating resin to prevent moisture intrusion, light blocking, short circuiting, etc.

[0003] For example, Patent Document 1 discloses a battery in which a power generating element is housed in a laminate film, and Patent Document 2 discloses a method for manufacturing a battery in which a power generating element in a charged state is covered with a thermosetting resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-40198 [Patent Document 2] Japanese Patent Application Publication No. 2018-116812 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, the battery is housed in a laminate film containing a heat-sealing resin, but the laminate film has a fused portion on the outer periphery of the battery, which reduces the energy density of the battery. Furthermore, the laminate film is often made of a general-purpose thermoplastic resin such as polypropylene resin or polyethylene resin, which means that the strength is low and the battery is easily damaged by external impacts, resulting in low reliability.

[0006] Furthermore, in Patent Document 2, in order to prevent short circuits between electrodes and maintain the strength of the battery, an insulating layer is formed by coating the power generating element with a thermosetting resin while the power generating element is in a charged state (i.e., the power generating element is in an expanded state), thereby suppressing cracking of the insulating layer. However, if an attempt is made to give the insulating layer strength by increasing the hardness, there is a problem that cracks are more likely to occur in the insulating layer when the power generating element contracts, thereby reducing the reliability of the battery.

[0007] The present disclosure is intended to solve the above-mentioned conventional problems, and has an object to provide a highly reliable battery. [Means for solving the problem]

[0008] A battery according to one embodiment of the present disclosure comprises a power generating element having at least one unit cell including an electrode layer, a counter electrode layer, and an electrolyte layer located between the electrode layer and the counter electrode layer, and an insulating member covering the power generating element, wherein the insulating member has a first member including a first main surface covering portion covering a first main surface of the power generating element, and a second member including a second main surface covering portion covering a second main surface of the power generating element opposite the first main surface, the second member being joined to the first member, wherein the joint between the first member and the second member overlaps with the side surface of the power generating element when viewed from a direction perpendicular to the side surface, and the elastic modulus of the first member is higher than the elastic modulus of the second member. [Effects of the Invention]

[0009] According to the present disclosure, a highly reliable battery can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of a battery according to the first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of a battery according to Modification 1 of Embodiment 1. As shown in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view of a battery according to Modification 2 of Embodiment 1. As shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of a battery according to Modification 3 of Embodiment 1. As shown in FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view of another battery according to Modification 3 of Embodiment 1. In FIG. [Figure 6] FIG. 6 is a diagram illustrating a process of covering the power generating element with an insulating member according to the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view of a battery according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Summary of the Disclosure) An outline of one aspect of the present disclosure is as follows.

[0012] A battery according to one embodiment of the present disclosure comprises a power generating element having at least one unit cell including an electrode layer, a counter electrode layer, and an electrolyte layer located between the electrode layer and the counter electrode layer, and an insulating member covering the power generating element, wherein the insulating member has a first member including a first main surface covering portion covering a first main surface of the power generating element, and a second member including a second main surface covering portion covering a second main surface of the power generating element opposite the first main surface, the second member being joined to the first member, wherein the joint between the first member and the second member overlaps with the side surface of the power generating element when viewed from a direction perpendicular to the side surface, and the elastic modulus of the first member is higher than the elastic modulus of the second member.

[0013] As a result, the power generating element is firmly protected by the first member, which has a relatively high elastic modulus, while the second member, which has a relatively low elastic modulus, is preferentially deformed by stress caused by the expansion and contraction of the power generating element during charging and discharging, thereby suppressing damage to the insulating member. In addition, because the joint is located on the outside of the side surface, the side surface is covered by the insulating member. Furthermore, because the first member and the second member are directly joined at the joint, the joint interface can be reduced compared to when a separate member is used for joining, and damage to the insulating member originating from the joint interface is suppressed. Therefore, because the power generating element can be effectively protected by the insulating member, a highly reliable battery can be realized.

[0014] Furthermore, for example, the first principal surface covering portion and the second principal surface covering portion may have different thicknesses.

[0015] This makes it possible to suppress cracking of the insulating member by thickening the main surface on the side that is more susceptible to shocks such as vibrations and / or the main surface on the side that is more susceptible to stress, thereby further improving the reliability of the battery.

[0016] Furthermore, for example, the thickness of the first principal surface covering portion may be greater than the thickness of the second principal surface covering portion.

[0017] This increases the thickness of the first main surface covering portion in the first member, which has a relatively high elastic modulus, and further reduces damage to the power generating element due to external impacts or the like.

[0018] Furthermore, for example, the first principal surface covering portion and the second principal surface covering portion may have a thickness of 10 μm or more.

[0019] This increases the strength of the insulating member, further reducing damage to the power generating element.

[0020] Furthermore, for example, the first member and the second member may be in contact with the side surface.

[0021] This prevents the side surfaces of the power generating element from being exposed, thereby preventing deterioration of the materials of the power generating element.

[0022] Furthermore, for example, the area where the second member and the side surface contact each other may be larger than the area where the first member and the side surface contact each other.

[0023] This increases the contact area between the side surface and the second member, which is easily deformed by stress caused by expansion and contraction of the power generating element, thereby further preventing damage to the insulating member.

[0024] Furthermore, for example, at least one of the first member and the second member may include a resin.

[0025] This allows for easy processing by heating or the like, thereby simplifying the battery manufacturing process.

[0026] Furthermore, for example, the first member and the second member may contain the same type of resin.

[0027] This increases the compatibility between the first member and the second member, thereby increasing the bonding strength of the bonded portion between the first member and the second member.

[0028] Furthermore, for example, the side surface may be a flat surface.

[0029] This makes it easier to cover the side surfaces of the power generating element with the insulating member.

[0030] Furthermore, for example, the power generating element may have a plurality of the unit cells stacked one on top of the other.

[0031] This makes it possible to improve the reliability even in a high-capacity or high-voltage stacked battery.

[0032] Furthermore, for example, the electrolyte layer may include a solid electrolyte having lithium ion conductivity.

[0033] This makes it possible to improve the reliability of a lithium ion battery containing a solid electrolyte.

[0034] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0035] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0036] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel, terms indicating the shape of elements, such as flat and rectangular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0037] In addition, the drawings are not necessarily strict illustrations, and the same reference numerals are used to designate substantially the same components in the drawings, and redundant explanations are omitted or simplified.

[0038] In this specification and drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. In each embodiment, the z-axis direction is the stacking direction of the battery. The positive direction of the z-axis is the upper side in the z-axis direction, and the negative direction of the z-axis is the lower side in the z-axis direction. In this specification, "planar view" means the case where the battery is viewed along the z-axis. In this specification, "thickness" refers to the length of each layer in the stacking direction.

[0039] In this specification, the terms "upper" and "lower" in the battery configuration do not refer to the upper direction (vertically upper) and lower direction (vertically lower) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in the stacking configuration. Furthermore, the terms "upper" and "lower" are used not only when two components are arranged closely to each other and are in contact with each other, but also when two components are arranged with a gap between them and another component is present between them.

[0040] (Embodiment 1) The following describes the battery according to embodiment 1. The battery according to embodiment 1 is a single cell including one electrode layer and one counter electrode layer.

[0041] [composition] First, the configuration of the battery according to the first embodiment will be described with reference to the drawings.

[0042] Fig. 1 is a schematic cross-sectional view of a battery 100 according to this embodiment. Fig. 1 shows a cross section of the battery 100 cut along the stacking direction.

[0043] As shown in FIG. 1 , a battery 100 according to this embodiment includes a power generating element 60 having at least one unit cell 50, and an insulating member 40 covering the power generating element 60. The battery 100 is, for example, an all-solid-state battery. In this embodiment, the power generating element 60 is composed of one unit cell 50, but may be composed of a plurality of unit cells 50. The unit cell 50 includes an electrode layer 10, a counter electrode layer 20, and a solid electrolyte layer 30, which is an example of an electrolyte layer, located between the electrode layer 10 and the counter electrode layer 20. Each component of the battery 100 will be described in detail below.

[0044] The power generating element 60 has a structure in which an electrode layer 10, a solid electrolyte layer 30, and a counter electrode layer 20 are laminated in this order. The shape of the power generating element 60 is, for example, a rectangular parallelepiped. The power generating element 60 may have other shapes, such as a cylindrical or polygonal prism, as long as it has the above-mentioned laminated structure.

[0045] The power generating element 60 has a first main surface 61, a second main surface 62, and a side surface 63. The first main surface 61 is a plane perpendicular to the stacking direction, and is a plane on which a part of the electrode layer 10 (specifically, a part of the current collector 11) is exposed. The second main surface 62 is a plane on the opposite side of the power generating element 60 from the first main surface 61, and is a plane on which a part of the counter electrode layer 20 (specifically, a part of the current collector 21) is exposed. The first main surface 61 and the second main surface 62 are, for example, parallel to each other. The side surface 63 extends from an end of the first main surface 61 in a direction intersecting the first main surface 61 and connects to an end of the second main surface 62. The side surface 63 is, for example, perpendicular to the first main surface 61 and the second main surface 62. The side surface 63 is, for example, a flat surface. This makes it easier to cover the side surface 63 of the power generating element 60 with the insulating member 40, and by improving the adhesion between the insulating member 40 and the power generating element 60, the reliability of the battery 100 can be further improved.

[0046] The electrode layer 10 includes a current collector 11 and an electrode active material layer 12 located between the current collector 11 and the solid electrolyte layer 30 .

[0047] The current collector 11 is in contact with the lower surface of the electrode active material layer 12 and covers the lower surface of the electrode active material layer 12. The lower surface of the current collector 11 is covered by the first member 41 of the insulating member 40, and specifically, is in contact with the first main surface covering portion 41a of the first member 41.

[0048] Known materials can be used as the material for the current collector 11. For example, the current collector 11 is a foil, plate, or mesh-like material made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these metals.

[0049] The current collector 11 may be electrically connected to a lead terminal for connecting to the outside. In this case, the lead terminal is exposed and not covered by the insulating member 40. Also, a part of the current collector 11 may be exposed and not covered by the insulating member 40 for electrical connection to the outside.

[0050] The electrode active material layer 12 is located on the current collector 11. The electrode active material layer 12 and the counter electrode active material layer 22 face each other with the solid electrolyte layer 30 sandwiched therebetween. The lower surface of the electrode active material layer 12 contacts the current collector 11. The width of the electrode active material layer 12 (the length in the direction perpendicular to the stacking direction, the length in the x-axis direction in FIG. 1 ) is smaller than the width of the current collector 11, and the upper and side surfaces of the electrode active material layer 12 are covered with the solid electrolyte layer 30. The width of the electrode active material layer 12 is smaller than the width of the counter electrode active material layer 22. The current collector 11, the electrode active material layer 12, and the counter electrode active material layer 22 may have the same width. The width of the electrode active material layer 12 may be larger than the width of the counter electrode active material layer 22. The side surfaces of the electrode active material layer 12 may be covered with an insulating member 40 instead of being covered with the solid electrolyte layer 30. The materials used for the electrode active material layer 12 will be described later.

[0051] The electrode layer 10 does not necessarily have to include the current collector 11, and for example, a lead terminal for extracting current may be directly connected to the electrode active material layer 12. Furthermore, when the power generating element 60 has a plurality of unit cells 50, the current collector of adjacent unit cells 50 may be shared. In other words, the electrode layer 10 may include only the electrode active material layer 12 out of the current collector 11 and the electrode active material layer 12.

[0052] The counter electrode layer 20 has a current collector 21 and a counter electrode active material layer 22 located between the current collector 21 and the solid electrolyte layer 30 .

[0053] The current collector 21 is in contact with and covers the upper surface of the counter electrode active material layer 22. The upper surface of the current collector 21 is covered by the second member 42 of the insulating member 40, and specifically, is in contact with the second main surface covering portion 42a of the second member 42. The material of the current collector 21 can be the same as the material of the current collector 11 described above.

[0054] The current collector 21 may be electrically connected to a lead terminal for connecting to the outside. In this case, the lead terminal is exposed and not covered by the insulating member 40. Furthermore, a part of the current collector 21 may be exposed and not covered by the insulating member 40 for electrical connection to the outside.

[0055] The counter electrode active material layer 22 is stacked on the solid electrolyte layer 30 and disposed opposite the electrode active material layer 12. The upper surface of the counter electrode active material layer 22 contacts the current collector 21. The width of the counter electrode active material layer 22 is the same as the width of the current collector 21. The width of the counter electrode active material layer 22 may be narrower than the current collector 21, and the side surface of the counter electrode active material layer 22 may be covered with the solid electrolyte layer 30 or the insulating member 40. The materials used for the counter electrode active material layer 22 will be described later.

[0056] The counter electrode layer 20 does not necessarily include the current collector 21, and for example, a lead terminal for extracting current may be directly connected to the counter electrode active material layer 22. Furthermore, when the power generating element 60 has a plurality of unit cells 50, the current collector of adjacent unit cells 50 may be shared. In other words, of the current collector 21 and the counter electrode active material layer 22, the counter electrode layer 20 may include only the counter electrode active material layer 22.

[0057] The solid electrolyte layer 30 is located between the electrode active material layer 12 and the counter electrode active material layer 22. The solid electrolyte layer 30 is in contact with the lower surface of the counter electrode active material layer 22. The solid electrolyte layer 30 is also in contact with the upper and side surfaces of the electrode active material layer 12. The solid electrolyte layer 30 is also in contact with the current collector 11.

[0058] The solid electrolyte layer 30 includes at least a solid electrolyte and may include a binder material as needed. The solid electrolyte layer 30 may include a solid electrolyte having lithium ion conductivity.

[0059] As the solid electrolyte, known materials that conduct metal ions, such as lithium ion conductors, sodium ion conductors, or magnesium ion conductors, can be used. Examples of solid electrolytes that can be used include solid electrolyte materials such as sulfide solid electrolytes, halogen-based solid electrolytes, and oxide solid electrolytes. As the sulfide solid electrolyte, materials that can conduct lithium ions, such as a composite of lithium sulfide (LiS) and diphosphorus pentasulfide (P2S5), can be used. Furthermore, sulfides such as LiS-SiS2, LiS-B2S3, or LiS-GeS2 can also be used. Sulfides obtained by adding at least one of LiN, LiCl, LiBr, LiPO4, and Li4SiO4 to the above sulfides as an additive can also be used.

[0060] As an oxide solid electrolyte, materials that can conduct lithium ions include, for example, Li7La3Zr2O 12 (LLZ), Li 1.3 Al 0.3 Ti 1.7(PO4)3(LATP) or (La,Li)TiO3(LLTO) are used.

[0061] As the binder material, for example, elastomers are used, and organic compounds such as polyvinylidene fluoride, acrylic resin, or cellulose resin may also be used.

[0062] The planar shape of each of the current collector 11, the electrode active material layer 12, the current collector 21, the counter electrode active material layer 22, and the solid electrolyte layer 30 is, for example, rectangular, but may also be circular, elliptical, polygonal, etc. Furthermore, the thickness (length in the z-axis direction), width (length in the x-axis direction), and depth (length in the y-axis direction) of each of the current collector 11, the electrode active material layer 12, the current collector 21, the counter electrode active material layer 22, and the solid electrolyte layer 30 are not particularly limited and can have any size.

[0063] In this embodiment, for example, the electrode layer 10 having the electrode active material layer 12 is a positive electrode layer having a positive electrode active material layer, and the counter electrode layer 20 having the counter electrode active material layer 22 is a negative electrode layer having a negative electrode active material layer. In this case, the counter electrode layer 20 side, which is the negative electrode layer that is likely to expand during charging, is covered with the second member 42 having a relatively low elastic modulus as described below, so that the insulating member 40 is less likely to be damaged by stress due to the expansion of the negative electrode layer. Note that the electrode layer 10 having the electrode active material layer 12 may be a negative electrode layer having a negative electrode active material layer, and the counter electrode layer 20 having the counter electrode active material layer 22 may be a positive electrode layer having a positive electrode active material layer.

[0064] The positive electrode active material layer contains at least a positive electrode active material, and may contain at least one of a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0065] The positive electrode active material may be a known material capable of absorbing and releasing (inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, or magnesium ions. Examples of the positive electrode active material capable of extracting and inserting lithium ions include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO), and lithium-nickel-manganese-cobalt composite oxide (LNMCO).

[0066] The solid electrolyte may be any of the above-described solid electrolyte materials. The conductive additive may be, for example, a conductive material such as acetylene black, carbon black, graphite, or carbon fiber. The binder may be any of the above-described binder materials.

[0067] The negative electrode active material layer contains at least a negative electrode active material, and may contain, as necessary, at least one of a solid electrolyte, a conductive additive, and a binder material, similar to those of the positive electrode active material layer.

[0068] The negative electrode active material may be a known material capable of occluding and releasing (inserting and desorbing, or dissolving and precipitating) lithium ions, sodium ions, or magnesium ions. Examples of materials capable of occluding and inserting lithium ions include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-baked carbon, metallic lithium, lithium alloys, and oxides of lithium and transition metal elements.

[0069] The solid electrolyte may be the solid electrolyte material described above, the conductive additive may be the conductive material described above, and the binder may be the binder material described above.

[0070] The insulating member 40 has a first member 41 and a second member 42. The insulating member 40 covers the first main surface 61, the second main surface 62, and the side surfaces 63 of the power generating element 60. The insulating member 40 covers, for example, all of the side surfaces 63 of the power generating element 60. The insulating member 40 may seal the power generating element 60. Note that some of the side surfaces 63 may not be covered by the insulating member 40. When the power generating element 60 has a rectangular parallelepiped shape with four side surfaces 63, the insulating member 40 may cover, for example, all of the four side surfaces 63, or may cover two of the four side surfaces 63 that are arranged opposite each other.

[0071] The first member 41 includes a first main surface covering portion 41a that covers the first main surface 61 of the power generating element 60, and a first side surface covering portion 41b that extends from an end of the first main surface covering portion 41a toward the power generating element 60 of the first main surface covering portion 41a and covers the side surface 63. The first member 41 is in contact with the first main surface 61 and the side surface 63. Specifically, the first main surface covering portion 41a is in contact with the first main surface 61, and the first side surface covering portion 41b is in contact with the side surface 63. This prevents the side surface 63 of the power generating element 60 from being exposed, which could cause deterioration of the materials of the power generating element 60. The first main surface covering portion 41a is, for example, flat.

[0072] The second member 42 includes a second main surface covering portion 42a that covers the second main surface 62 of the power-generating element 60, and a second side surface covering portion 42b that extends from an end of the second main surface covering portion 42a toward the power-generating element 60 side of the second main surface covering portion 42a and covers the side surface 63. The second member 42 is in contact with the second main surface 62 and the side surface 63. Specifically, the second main surface covering portion 42a is in contact with the second main surface 62, and the second side surface covering portion 42b is in contact with the side surface 63. This prevents the side surface 63 of the power-generating element 60 from being exposed, which could cause deterioration of the materials of the power-generating element 60. The second main surface covering portion 42a is, for example, flat.

[0073] The joint 40a between the first member 41 and the second member 42, more specifically, the joint 40a between the first side surface covering portion 41b and the second side surface covering portion 42b, overlaps the side surface 63 when viewed from a direction perpendicular to the side surface 63 of the power-generating element 60 (the x-axis direction in FIG. 1 ). The joint 40a is, for example, a location where the first member 41 and the second member 42 are directly joined at the interface between the first member 41 and the second member 42. The joint 40a may be formed by interaction between the surfaces of the first member 41 and the second member 42, or may be formed by mixing and joining the materials of the first member 41 and the second member 42. In this way, when viewed from a direction perpendicular to the side surface 63 of the power-generating element 60, the first member 41 and the second member 42 are joined at the joint 40a that overlaps the side surface 63, allowing the side surface 63 to be covered by the insulating member 40. Furthermore, by directly joining the first member 41 and the second member 42, which are different members, the joint interface can be reduced compared to when the first member 41 and the second member 42 are joined via an adhesive or the like, making it easier to prevent damage at the joint 40a of the insulating member 40.

[0074] Furthermore, in the illustrated example, the joint portion 40a extends in a direction perpendicular to the side surface 63, but it may extend in a direction inclined relative to the direction perpendicular to the side surface 63. Furthermore, the first member 41 and the second member 42 may have an overlapping portion when viewed from a direction perpendicular to the side surface 63. In other words, one of the first side surface covering portion 41b and the second side surface covering portion 42b may cover the side opposite to the other side surface 63.

[0075] Furthermore, when viewed from a direction perpendicular to the side surface 63, the joint portion 40a overlaps with the center portion of the side surface 63 in the stacking direction. The contact area between the first member 41 and the side surface 63 is the same as the contact area between the second member 42 and the side surface 63. Note that the contact area between the first member 41 and the side surface 63 may be different from the contact area between the second member 42 and the side surface 63.

[0076] Furthermore, the elastic modulus of the first member 41 is higher than that of the second member 42. The elastic modulus is, for example, Young's modulus. This provides the insulating member 40 with flexibility that prevents breakage due to preferential deformation of the second member 42 caused by stress caused by expansion and contraction of the power generating element 60 during charging and discharging, while maintaining high mechanical strength due to the first member 41. This effectively protects the power generating element 60, thereby improving the reliability of the battery 100. When using the battery 100, for example, the battery 100 is positioned so that the first member 41 is positioned in a direction that is susceptible to external impacts and stresses.

[0077] The elastic modulus of the first member 41 and the second member 42 is adjusted to a desired elastic modulus by, for example, the type of material and / or the compounding ratio of the material.

[0078] The Young's modulus of the first member 41 is, for example, 4 GPa or more, and may be 5 GPa or more. There is no particular upper limit to the Young's modulus of the first member 41, and the Young's modulus may be set to a value that can protect the power generating element 60 depending on the thickness of the first member 41, etc.

[0079] The Young's modulus of the second member 42 is, for example, 0.1 GPa or more and 4 GPa or less, and may be 0.2 GPa or more and 2 GPa or less, which allows the second member 42 to have appropriate flexibility and strength.

[0080] The difference between the Young's modulus of the first member 41 and the Young's modulus of the second member 42 is, for example, 1 GPa or more, and may be 2 GPa or more.

[0081] The materials for the first member 41 and the second member 42 are not particularly limited as long as they satisfy the above-described elastic modulus relationship and have the heat resistance and insulating properties required for use in the battery 100. At least one of the first member 41 and the second member 42 contains, for example, a resin. This allows for easy processing by heating, etc., thereby simplifying the manufacturing process of the battery 100. Furthermore, the first member 41 and the second member 42 can be joined by heating and pressure, etc., without using adhesives, etc. Furthermore, at least one of the first member 41 and the second member 42 contains, for example, an inorganic compound. This allows for the elastic modulus of the first member 41 and the second member 42 to be adjusted by adjusting the amount of the high-strength inorganic compound added.

[0082] The first member 41 and the second member 42 may each be composed of, for example, resin only, or may be composed of resin and an inorganic compound. Furthermore, when the first member 41 and the second member 42 contain resin, the first member 41 and the second member 42 may each be composed of a resin composition whose main component is a thermosetting resin and / or a thermoplastic resin, which softens when heated and has film-forming ability. The first member 41 and the second member 42 may each be composed of a resin composition containing an inorganic compound. The first member 41 and the second member 42 may contain the same type of material.

[0083] Examples of resins contained in the first member 41 and the second member 42 include epoxy resin, acrylic resin, polyimide resin, polyamideimide resin, polycyanate resin, polyester resin, silicone resin, and thermosetting polyphenylene ether resin. The resins contained in the first member 41 and the second member 42 may be thermosetting resins or thermoplastic resins. The first member 41 and the second member 42 may each be made of one type of resin or a combination of two or more types of resins. Furthermore, the first member 41 and the second member 42 may each be made of a plurality of film layers having a multilayer structure.

[0084] Furthermore, the first member 41 and the second member 42 may contain the same type of resin. In this case, for example, the first member 41 contains a larger amount of a high-strength material, such as an inorganic material, than the second member 42, thereby making the elastic modulus of the first member 41 higher than the elastic modulus of the second member 42. When the first member 41 and the second member 42 contain the same type of resin, the compatibility between the first member 41 and the second member 42 is improved, and therefore the bonding strength of the bonding portion 40a between the first member 41 and the second member 42 can be increased.

[0085] The second member 42 may also contain a resin such as a crystalline resin or a cross-linkable resin that has a glass transition temperature lower than room temperature and is solid at room temperature. This allows the second member 42 to contain a resin that does not undergo glass transition at room temperature, thereby increasing flexibility and making the second member 42 even less susceptible to damage due to stress caused by expansion and contraction of the power generating element 60 during charge and discharge.

[0086] Examples of inorganic materials contained in the first member 41 and the second member 42 include barium oxide, calcium carbonate, barium titanate, silicon oxide, titanium oxide, and aluminum oxide.

[0087] The thickness L1 of the first principal surface covering portion 41a is the same as the thickness L2 of the second principal surface covering portion 42a. Each of the thickness L1 of the first principal surface covering portion 41a and the thickness L2 of the second principal surface covering portion 42a is, for example, 10 μm or more, or may be 50 μm or more, or may be 200 μm or more. This increases the strength of the insulating member 40, thereby further suppressing damage to the power-generating element 60. From the standpoint of volumetric energy density, each of the thickness L1 of the first principal surface covering portion 41a and the thickness L2 of the second principal surface covering portion 42a may be 1000 μm or less, or may be 200 μm or less, or may be 100 μm or less.

[0088] The thickness L1 of the first principal surface covering portion 41a may be different from the thickness L2 of the second principal surface covering portion 42a. In this case, by thickening the principal surface on the side that is more susceptible to shocks such as vibrations and / or the principal surface on the side that is more susceptible to stress, cracking of the insulating member 40 can be suppressed, and the reliability of the battery 100 can be further improved.

[0089] Furthermore, the thickness of the first side surface covering portion 41b is, for example, the same as the thickness of the second side surface covering portion 42b. The thickness of the first side surface covering portion 41b may be different from the thickness of the second side surface covering portion 42b. The thickness of the first side surface covering portion 41b and the thickness of the second side surface covering portion 42b may be the same as or different from the thickness L1 of the first main surface covering portion 41a or the thickness L2 of the second main surface covering portion 42a, respectively. The thickness of the first side surface covering portion 41b and the thickness of the second side surface covering portion 42b are, for example, 10 μm or more.

[0090] Furthermore, the surface of first side surface covering portion 41b opposite side surface 63 is flush with the surface of second side surface covering portion 42b opposite side surface 63. In other words, the surface of first side surface covering portion 41b opposite side surface 63 and the surface of second side surface covering portion 42b opposite side surface 63 form a flat plane. This makes it difficult for gaps to form between batteries 100 when batteries 100 are stacked and used, improving energy density.

[0091] Although not shown, the battery 100 may further include a plate-shaped reinforcing member that covers at least one of the upper and lower surfaces of the insulating member 40. For example, the reinforcing member is provided so as to contact the surface of the second main surface covering portion 42a opposite to the power-generating element 60 side. This protects the second member 42, which has a relatively low elastic modulus, and therefore prevents damage to the power-generating element 60. Examples of the reinforcing member include a ceramic substrate containing alumina or the like, a resin substrate containing epoxy resin or the like, and prepreg formed by impregnating carbon fiber or glass cloth with a resin such as epoxy resin. The reinforcing member may be provided so as to contact the surface of the first main surface covering portion 41a opposite to the power-generating element 60 side.

[0092] As described above, the battery 100 includes the power generating element 60 and the insulating member 40 that covers the power generating element 60. The insulating member 40 has a first member 41 and a second member 42 that is joined to the first member 41, and the elastic modulus of the first member 41 is higher than the elastic modulus of the second member 42. Furthermore, the joint 40a between the first member 41 and the second member 42 overlaps with the side surface 63 of the power generating element 60 when viewed from a direction perpendicular to the side surface 63.

[0093] As a result, the power generating element 60 is firmly protected by the first member 41, which has a relatively high elastic modulus, and the second member 42, which has a relatively low elastic modulus, is preferentially deformed by stress caused by expansion and contraction of the power generating element 60 during charge and discharge, thereby suppressing damage to the insulating member 40. Furthermore, because the joint 40a is located outside the side surface 63, the side surface 63 is covered by the insulating member 40. Furthermore, because the first member 41 and the second member 42 are directly joined at the joint 40a, the joint interface can be reduced compared to when a separate member is used for joining, and damage to the insulating member 40 originating from the joint interface is suppressed. Therefore, the power generating element 60 can be effectively protected by the insulating member 40, resulting in a highly reliable battery 100.

[0094] [Variation 1] The following describes Modification 1 of Embodiment 1. In the following description of Modification 1 of Embodiment 1, differences from Embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0095] Fig. 2 is a schematic cross-sectional view of a battery 101 according to this modification. Fig. 2 shows a cross section of the battery 101 cut along the stacking direction. The battery 101 differs from the battery 100 in that it includes an insulating member 140 instead of the insulating member 40.

[0096] As shown in FIG. 2, the battery 101 according to this modification includes a power generating element 60 and an insulating member 140 that covers the power generating element 60.

[0097] The insulating member 140 has a first member 141 and a second member 142 .

[0098] The first member 141 includes a first main surface covering portion 41a that covers the first main surface 61 of the power generating element 60, and a first side surface covering portion 141b that extends from the end of the first main surface covering portion 41a toward the power generating element 60 side of the first main surface covering portion 41a and covers the side surface 63.

[0099] The second member 142 includes a second main surface covering portion 42a that covers the second main surface 62 of the power generating element 60, and a second side surface covering portion 142b that extends from the end of the second main surface covering portion 42a toward the power generating element 60 side of the second main surface covering portion 42a and covers the side surface 63.

[0100] The joint 140a between the first member 141 and the second member 142, more specifically, the joint 140a between the first side covering portion 141b and the second side covering portion 142b, overlaps with the side surface 63 when viewed from a direction perpendicular to the side surface 63 of the power generating element 60.

[0101] When viewed from a direction perpendicular to the side surface 63, the joint portion 140a is located closer to the electrode layer 10 than the center of the side surface 63 in the stacking direction. The contact area between the first member 141 and the side surface 63 is larger than the contact area between the second member 142 and the side surface 63. This increases the contact area between the second member 142, which is easily deformed by stress caused by expansion and contraction of the power generating element 60, and the side surface 63, further reducing damage to the insulating member 140.

[0102] [Variation 2] The following describes Modification 2 of Embodiment 1. In the following description of Modification 2 of Embodiment 1, differences from Embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0103] Fig. 3 is a schematic cross-sectional view of a battery 102 according to this modification. Fig. 3 shows a cross section of the battery 102 cut along the stacking direction. The battery 102 differs from the battery 100 in that it includes an insulating member 240 instead of the insulating member 40.

[0104] As shown in FIG. 3, the battery 102 according to this modification includes a power generating element 60 and an insulating member 240 that covers the power generating element 60.

[0105] The insulating member 240 has a first member 241 and a second member 242 .

[0106] The first member 241 includes a first main surface covering portion 241a that covers the first main surface 61 of the power generating element 60, and a first side surface covering portion 241b that extends from the end of the first main surface covering portion 241a toward the power generating element 60 side of the first main surface covering portion 241a and covers the side surface 63.

[0107] The second member 242 includes a second main surface covering portion 42a that covers the second main surface 62 of the power generating element 60, and a second side surface covering portion 242b that extends from the end of the second main surface covering portion 42a toward the power generating element 60 side of the second main surface covering portion 42a and covers the side surface 63.

[0108] The joint 240a between the first member 241 and the second member 242, more specifically, the joint 240a between the first side covering portion 241b and the second side covering portion 242b, overlaps with the side surface 63 when viewed from a direction perpendicular to the side surface 63 of the power generating element 60.

[0109] When viewed from a direction perpendicular to the side surface 63, the joint portion 240a is located closer to the counter electrode layer 20 than the center of the stacking direction of the side surface 63. The contact area between the first member 241 and the side surface 63 is smaller than the contact area between the second member 242 and the side surface 63. This increases the contact area between the first member 241, which has a relatively large elastic modulus, and the side surface 63, further preventing damage to the power generating element 60 due to external impacts, etc.

[0110] Furthermore, the thickness L1 of the first principal surface covering portion 241a is different from the thickness L2 of the second principal surface covering portion 42a. Specifically, the thickness L1 of the first principal surface covering portion 241a is greater than the thickness L2 of the second principal surface covering portion 42a. This increases the thickness L1 of the first principal surface covering portion 241a in the first member 241, which has a relatively high elastic modulus, thereby further preventing damage to the power generating element 60 due to external impacts, etc.

[0111] [Variation 3] The following describes Modification 3 of Embodiment 1. In the following description of Modification 3 of Embodiment 1, differences from Embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0112] Fig. 4 is a schematic cross-sectional view of a battery 103 according to this modification. Fig. 4 shows a cross section of the battery 103 cut along the stacking direction. The battery 103 differs from the battery 100 in that it includes an insulating member 340 instead of the insulating member 40.

[0113] As shown in FIG. 4, the battery 103 according to this modification includes a power generating element 60 and an insulating member 340 that covers the power generating element 60.

[0114] The insulating member 340 includes a first member 341 and a second member 342 .

[0115] The first member 341 includes a first main surface covering portion 41a that covers the first main surface 61 of the power generating element 60, and a first side surface covering portion 341b that extends from the end of the first main surface covering portion 41a toward the power generating element 60 side of the first main surface covering portion 41a and covers the side surface 63.

[0116] The second member 342 includes a second main surface covering portion 42a that covers the second main surface 62 of the power generating element 60, and a second side surface covering portion 342b that extends from the end of the second main surface covering portion 42a toward the power generating element 60 side of the second main surface covering portion 42a and covers the side surface 63.

[0117] The joint 340a between the first member 341 and the second member 342, more specifically the joint 340a between the first side surface covering portion 341b and the second side surface covering portion 342b, overlaps with the side surface 63 of the power generating element 60 when viewed from a direction perpendicular to the side surface 63. The insulating member 340 has a convex shape 340b where the joint 340a is provided, which protrudes in a direction away from the side surface 63. This increases the strength against external impacts and stresses, as well as stresses due to expansion and contraction of the power generating element 60 during charge and discharge. A gap 343 is provided between the joint 340a and the side surface 63. This reduces stresses due to external impacts and the like, as well as stresses due to expansion and contraction of the power generating element 60 during charge and discharge.

[0118] Note that the gap 343 does not necessarily have to be provided between the joint 340a and the side surface 63. Fig. 5 is a schematic cross-sectional view of another battery 103a according to this modification. Fig. 5 shows a cross section of the battery 103a cut along the stacking direction. The battery 103a is a battery in which the gap 343 of the battery 103 is not provided.

[0119] As shown in FIG. 5, the battery 103a includes a power generating element 60 and an insulating member 345 that covers the power generating element 60.

[0120] The insulating member 345 has a first member 346 and a second member 347 .

[0121] The first member 346 includes a first main surface covering portion 41a that covers the first main surface 61 of the power generating element 60, and a first side surface covering portion 346b that extends from the end of the first main surface covering portion 41a toward the power generating element 60 side of the first main surface covering portion 41a and covers the side surface 63.

[0122] The second member 347 includes a second main surface covering portion 42a that covers the second main surface 62 of the power generating element 60, and a second side surface covering portion 347b that extends from the end of the second main surface covering portion 42a toward the power generating element 60 side of the second main surface covering portion 42a and covers the side surface 63.

[0123] The joint 345a between the first member 346 and the second member 347, more specifically the joint 345a between the first side surface covering portion 346b and the second side surface covering portion 347b, overlaps with the side surface 63 of the power generating element 60 when viewed from a direction perpendicular to the side surface 63. Furthermore, the insulating member 345 has a convex shape 345b where the joint 345a is provided that protrudes in a direction away from the side surface 63. This increases the strength against external impacts and stresses.

[0124] [Battery manufacturing method] Next, an example of a method for manufacturing a battery according to the present embodiment will be described. The following description will focus on a method for manufacturing the battery 100 according to embodiment 1. Note that the manufacturing method described below is just an example, and the method for manufacturing a battery according to the present embodiment is not limited to the following method.

[0125] First, the power generating element 60 is formed. The power generating element 60 can be formed using a known manufacturing method for power generating elements of batteries. In this embodiment, the power generating element 60 is composed of one unit cell 50, and therefore the power generating element 60 is formed by forming the unit cell 50. For example, first, an electrode plate is formed by stacking an electrode active material layer 12 and a solid electrolyte layer 30 in this order on a current collector 11. Then, a counter electrode plate is formed by stacking a counter electrode active material layer 22 and a solid electrolyte layer 30 in this order on a current collector 21. The formed electrode plate and counter electrode plate are stacked so that their solid electrolyte layers 30 are in contact with each other. The stacked laminate is pressed from both sides in the stacking direction using a plate press to obtain a power generating element 60 composed of one unit cell 50.

[0126] Next, the obtained power generating element 60 is covered with the insulating member 40. FIG.

[0127] First, as shown in (a) of Figure 6, the top and bottom of the power generating element 60 are sandwiched between sheets of resin composition. The sheet-like resin composition is a resin composition that is solid at room temperature and contains, for example, the resin and inorganic material exemplified above as the materials for the first member 41 and the second member 42. For example, a sheet-like first resin composition 941 that will be the material for the first member 41 is placed on the first main surface 61 side of the power generating element 60, and a sheet-like second resin composition 942 that will be the material for the second member 42 is placed on the second main surface 62 side of the power generating element 60.

[0128] Next, the power generating element 60 sandwiched between the first resin composition 941 and the second resin composition 942 is heated while being held in a mold or the like, and as shown in (b) of Figure 6, the first resin composition 941 and the second resin composition 942 begin to flow.

[0129] For example, the power generating element 60 sandwiched between the first resin composition 941 and the second resin composition 942 is placed in a rectangular parallelepiped mold, and the first resin composition 941, the power generating element 60, and the second resin composition 942 are heated and pressurized. As a result, as shown in FIG. 6(c), the first resin composition 941 and the second resin composition 942 are bonded to each other at positions that overlap the side surface 63 of the power generating element 60 when viewed from a direction perpendicular to the side surface 63, forming a first member 41 and a second member 42 bonded at the joint 40a. This results in a battery 100 in which the power generating element 60 is covered with the insulating member 40.

[0130] Moreover, by adjusting the shapes of the first resin composition 941 and the second resin composition 942, the shape of the mold, and the conditions of heating and pressing, it is also possible to form batteries 101 and 102 other than the battery 100.

[0131] Furthermore, a vacuum laminator, a vacuum press, or the like may be used to heat and pressurize the power generating element 60 sandwiched between the first resin composition 941 and the second resin composition 942. For example, the power generating element 60 sandwiched between the first resin composition 941 and the second resin composition 942 is further sandwiched between carrier films and transported to a vacuum press, where it is heated and vacuum-pressed. As a result, the first resin composition 941 and the second resin composition 942 conform to the shape of the power generating element 60 and are bonded at positions that overlap the side surfaces 63 of the power generating element 60 when viewed perpendicularly to the side surfaces 63, thereby forming the first and second members. At this time, by adjusting the temperature and vacuum press conditions, it is possible to form a battery 103 in which a void 343 is provided and the power generating element 60 is covered with an insulating member 340, as shown in FIG. 6(d), or a battery 103a in which a void 343 is not provided and the power generating element 60 is covered with an insulating member 345, as shown in FIG. 6(e). Furthermore, since pressure is applied via the carrier film without using a mold or the like, the outside of the portion of the insulating member that covers the side surface 63 does not become a vertical surface, and convex shapes 340b and 345b are formed.

[0132] By using such a vacuum laminator or vacuum press device, the power generating element 60 sandwiched between the first resin composition 941 and the second resin composition 942 can be placed on a carrier film and continuously transported, heated, and manufactured with high productivity. Furthermore, during vacuum pressing, the power generating element 60 may be pressed from above and below with hot plates. This improves the smoothness of the upper and lower surfaces of the battery (in other words, the uniformity of the thickness of the insulating member). Furthermore, vacuum pressing may be performed multiple times.

[0133] The first resin composition 941 and the second resin composition 942 contain, for example, a thermosetting resin, which allows the first resin composition 941 and the second resin composition 942 to be easily softened by heating until curing progresses, and after curing, the shape is maintained without cooling, thereby shortening the vacuum pressing time.

[0134] In addition, in manufacturing the battery 100 shown in (c) of FIG. 6, after manufacturing the battery 103a as shown in (e) of FIG. 6, the end of the insulating member 345 may be cut to adjust the shape of the insulating member, thereby manufacturing the battery 100.

[0135] The method for covering the power generating element 60 with the insulating member 40 is not limited to the above method. The method for covering the power generating element 60 with the insulating member 40 may be, for example, a method for immersing the power generating element 60 in a resin composition, or a method for applying the resin composition to the surface of the power generating element 60 using a coating means such as a spray. Furthermore, the method for covering the power generating element 60 with the insulating member 40 may be a method for pouring the resin composition into a mold in which the power generating element 60 is placed.

[0136] (Embodiment 2) Next, a battery according to embodiment 2 will be described. The battery according to embodiment 2 is a stacked battery in which unit cells are stacked. In the following description, differences from embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified as appropriate.

[0137] Fig. 7 is a schematic cross-sectional view of a battery 200 according to this embodiment. Fig. 7 shows a cross section of the battery 200 cut along the stacking direction.

[0138] 7, the battery 200 according to this embodiment includes a power generating element 560 having a plurality of stacked unit cells 50, and an insulating member 540 covering the power generating element 560. In this embodiment, the power generating element 560 is composed of three unit cells 50, but may also be composed of two unit cells 50, or four or more unit cells 50.

[0139] The plurality of unit cells 50 are stacked such that one electrode layer 10 and the other counter electrode layer 20 of adjacent unit cells 50 in the stacking direction face each other. In other words, the battery 200 is a series-stacked battery. This allows a high-voltage battery 200 to be realized. In FIG. 7 , the current collectors 11 and 21 are stacked such that they are in contact with each other, but one of the adjacent current collectors 11 and 21 may be omitted, and the current collector may be shared by adjacent unit cells 50.

[0140] The insulating member 540 has a first member 541 and a second member 542 .

[0141] The first member 541 includes a first main surface covering portion 541a that covers the first main surface 561 of the power generating element 560, and a first side surface covering portion 541b that extends from the end of the first main surface covering portion 541a toward the power generating element 560 side of the first main surface covering portion 541a and covers the side surface 563.

[0142] The second member 542 includes a second main surface covering portion 542a that covers the second main surface 562 of the power generating element 560, and a second side surface covering portion 542b that extends from the end of the second main surface covering portion 542a toward the power generating element 560 side of the second main surface covering portion 542a and covers the side surface 563.

[0143] The joint 540a between the first member 541 and the second member 542, more specifically, the joint 540a between the first side covering portion 541b and the second side covering portion 542b, overlaps with the side surface 563 when viewed from a direction perpendicular to the side surface 563 of the power generating element 560.

[0144] Even in such a stacked battery 200 having a power generating element 560 having a plurality of unit cells 50, by covering the power generating element 560 with an insulating member 540 having a first member 541 and a second member 542, the same effects as those of the battery 100 of embodiment 1 can be obtained, and a highly reliable battery 200 can be realized.

[0145] The battery 200 is manufactured, for example, by stacking a plurality of unit cells 50 to form a power generating element 560, and covering the power generating element 560 with an insulating member 540 in a manner similar to the manufacturing method of the battery according to the first embodiment described above.

[0146] Although the battery 200 is a series-stacked battery, it may also be a battery including parallel-stacked power generating elements having a structure in which the electrode layers 10 or counter electrode layers 20 of adjacent unit cells 50 are stacked so as to face each other. A parallel-stacked battery can achieve a high-capacity battery.

[0147] (Other embodiments) While the battery and manufacturing method thereof according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments are also included within the scope of the present disclosure.

[0148] In the above embodiment, the unit cell of the power generating element is composed of a current collector, an electrode active material layer, an insulating layer, a solid electrolyte layer, and a counter electrode active material layer, but is not limited thereto. For example, within the range of allowable battery characteristics, a bonding layer or the like may be provided between each layer of the unit cell to reduce electrical resistance and improve bonding strength.

[0149] In the above embodiment, the insulating member is in direct contact with the power generating element to cover the power generating element, but this is not limiting. For example, other members such as a reinforcing member and an adhesive may be disposed between the insulating member and the power generating element.

[0150] In the above embodiment, the side surface of the power generating element is flat, but this is not limiting. For example, the side surface of the power generating element may have irregularities. The irregularities on the side surface allow the insulating member to fit into the irregularities, making the insulating member less likely to peel off from the power generating element.

[0151] Furthermore, the above-described embodiments can be modified, replaced, added, omitted, and the like in various ways within the scope of the claims or their equivalents. [Industrial Applicability]

[0152] The battery according to the present disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles. [Explanation of symbols]

[0153] 10 electrode layer 11, 21 Current collector 12 Electrode active material layer 20 Opposite Layer 22 Counter electrode active material layer 30 Solid electrolyte layer 40, 140, 240, 340, 345, 540 Insulating material 40a, 140a, 240a, 340a, 345a, 540a joint 41, 141, 241, 341, 346, 541 First member 41a, 241a, 541a 1st main surface covering part 41b, 141b, 241b, 341b, 346b, 541b First side surface covering portion 42, 142, 242, 342, 347, 542 Second member 42a, 542a 2nd main surface covering part 42b, 142b, 242b, 342b, 347b, 542b Second side covering part 50 unit cells 60, 560 power generation elements 61, 561 First main surface 62, 562 Second main surface 63, 563 Side 100, 101, 102, 103, 103a, 200 batteries 340b, 345b convex shape 343 void 941 First resin composition 942 Second resin composition

Claims

1. a power generating element having at least one unit cell including an electrode layer, a counter electrode layer, and an electrolyte layer located between the electrode layer and the counter electrode layer; an insulating member covering the power generating element; Equipped with The insulating member is a first member including a first main surface covering portion that covers a first main surface of the power generating element; a second member including a second main surface covering portion that covers a second main surface of the power generating element opposite to the first main surface, and that is joined to the first member; and a joint between the first member and the second member overlaps with a side surface of the power-generating element when viewed from a direction perpendicular to the side surface, The elastic modulus of the first member is higher than the elastic modulus of the second member, an area where the second member contacts the side surface is larger than an area where the first member contacts the side surface; battery.

2. The first principal surface covering portion and the second principal surface covering portion have different thicknesses. The battery of claim 1 .

3. The thickness of the first main surface covering portion is greater than the thickness of the second main surface covering portion. The battery according to claim 1 or 2.

4. The thickness of the first principal surface covering portion and the second principal surface covering portion is 10 μm or more, The battery according to any one of claims 1 to 3.

5. The first member and the second member contact the side surface. The battery of any one of claims 1 to 4.

6. At least one of the first member and the second member contains a resin. The battery of any one of claims 1 to 5.

7. The first member and the second member contain the same type of resin. The battery of claim 6.

8. The side surface is a flat surface. The battery of any one of claims 1 to 7.

9. The power generating element has a plurality of the unit cells stacked together. The battery of any one of claims 1 to 8.

10. The electrolyte layer contains a solid electrolyte having lithium ion conductivity.

10. The battery of claim 1.

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