Exterior materials, as well as solid-state batteries and electronic devices

Abstract

The present invention provides an exterior material capable of suppressing infiltration of water vapor. The present invention provides an exterior material which includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer, and in which the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer are both higher than 260°C.

Description

[Technical Field]

[0001] The present invention relates to an exterior material, a solid-state battery, and an electronic device. Specifically, the present invention relates to an exterior material, a solid-state battery including the exterior material, and an electronic device including the exterior material. [Background technology]

[0002] The exterior material is provided to cover the periphery of the electronic device to protect the electronic device, such as a battery, a circuit board, a composite module, or an electronic component.

[0003] Batteries include secondary batteries that can be repeatedly charged and discharged. Secondary batteries that can be repeatedly charged and discharged have been used for a variety of purposes. For example, secondary batteries are used as power sources for electronic devices such as smartphones and laptops.

[0004] In such secondary batteries, liquid electrolytes (electrolytic solutions) such as organic solvents have traditionally been used as a medium for transferring ions. However, secondary batteries using electrolytic solutions have problems such as leakage of the electrolytic solution. Therefore, development of solid-state batteries that use solid electrolytes instead of liquid electrolytes is underway. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6179576 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, conventional packaging materials may have a laminate structure including a metal layer, resin layers positioned on both sides of the metal layer, and an adhesive layer positioned between the metal layer and the resin layer. In this case, depending on the properties of the adhesive layer of the packaging material, there is a risk that the adhesive layer may not be able to maintain its adhesiveness properly. Therefore, when the packaging material is provided to cover the periphery of an electronic device such as a solid-state battery, there is a risk that water vapor may penetrate into the electronic device such as a solid-state battery through the adhesive layer.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide an exterior material that can suppress the penetration of water vapor, and an electronic device such as a solid-state battery that includes the exterior material. [Means for solving the problem]

[0008] In one embodiment of the present invention, a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer; The packaging material is provided in which the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C.

[0009] In addition, in one embodiment of the present invention, a battery element including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an exterior material covering the battery element; and a conductive part capable of extracting electricity from the battery element to the outside, the exterior packaging material includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer, The solid-state battery is provided, wherein the first thermoplastic resin layer and the second thermoplastic resin layer are exterior materials having melting points both higher than 260°C.

[0010] Furthermore, in one embodiment of the present invention, an electronic device; and an exterior material that covers the electronic device; the exterior packaging material includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer, The electronic device is an exterior material in which the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C. [Effects of the Invention]

[0011] The packaging material according to one embodiment of the present invention can prevent water vapor from penetrating. Furthermore, the solid-state battery and electronic device according to one embodiment of the present invention can prevent water vapor from penetrating into the interior thereof. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows an exterior packaging material according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing the manufacturing process of an exterior packaging material according to one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a solid state battery according to one embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a solid state battery according to one embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a solid state battery according to one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view that schematically shows how a solid state battery according to one embodiment of the present invention prevents water vapor from penetrating. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a solid state battery according to one embodiment of the present invention. [Figure 8] FIG. 8 is a perspective view schematically showing a solid state battery according to one embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a solid state battery (expanded state) according to one embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view that schematically shows a solid state battery according to one embodiment of the present invention (with a sealant). [Figure 11] FIG. 11 is a cross-sectional view schematically showing a solid state battery according to another embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view schematically showing a solid state battery according to another embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view schematically showing an electronic device according to one embodiment of the present invention. [Figure 14] FIG. 14 is a schematic diagram showing the manufacturing process of a solid state battery according to one embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view that schematically shows a conventional exterior material. [Figure 16] FIG. 16 is a cross-sectional view schematically showing a conventional solid-state battery. [Figure 17] FIG. 17 is a perspective view schematically showing a conventional solid state battery. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Exterior material of the present invention] Hereinafter, an exterior packaging material according to one embodiment of the present invention will be described in detail. While the description will be made with reference to the drawings as necessary, the contents shown in the drawings are merely shown as schematic examples for the purpose of understanding the present invention, and the overall appearance, dimensional ratios, etc. may differ from the actual parts.

[0014] FIG. 1 is a cross-sectional view that schematically shows an exterior packaging material according to one embodiment of the present invention.

[0015] As shown in FIG. 1, an exterior packaging material 11 according to one embodiment of the present invention includes a metal layer 11b, a first thermoplastic resin layer 11a located on a first main surface of the metal layer 11b, and a second thermoplastic resin layer 11c located on a second main surface of the metal layer 11b, and is characterized in that the melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are both higher than 260°C. Note that the term "thermoplastic resin" as used herein refers to a resin that softens when heated and solidifies when cooled, and that can reversibly repeat softening and solidification. The thermoplastic resin may be a resin that has thermal fusion properties.

[0016] Conventionally, in order to bond an adherend such as a resin layer to a metal layer, an adhesive layer has been interposed between the resin layer and the adherend. For example, a conventional packaging material 11' shown in FIG. 15 has an adhesive layer 11d' between a resin layer 11a' and a metal layer 11b' (an adhesive layer 11d' between the metal layer 11b' and the resin layer 11 (In some cases, an adhesive layer 11e' is also formed between the metal layer 11b and the resin layer 11c'. In contrast, in the packaging material 11 of the present invention, the two resin layers 11a, 11c located on the first and second main surface sides of the metal layer 11b are both thermoplastic resin layers having melting points that exceed the upper limit of the mounting temperature (see FIG. 1).

[0017] In this case, unlike conventional packaging materials, the two thermoplastic resin layers sandwiching the metal layer and / or the properties of each thermoplastic resin layer (softening upon heating and solidifying upon cooling) allow the resin surface to soften upon heating, conforming to the irregularities on the metal layer surface. As a result, the contact area between the resin layer surface and the metal layer surface increases. In addition, functional groups on the metal layer surface and those in the thermoplastic resin layer may form chemical bonds and / or physical bonds due to intermolecular forces between the metal layer surface and the thermoplastic resin layer. This allows the two thermoplastic resin layers to be bonded to the adherend, such as a metal layer, located between them, without necessarily using an adhesive layer. As a result, the shape of the laminated packaging can be maintained without necessarily using an adhesive layer.

[0018] Therefore, in contrast to conventional packaging materials that require the use of an adhesive layer and have the risk of water vapor penetrating through the adhesive, the present invention makes it possible to suppress the penetration of water vapor into the packaging material itself. As a result, when a packaging material with suppressed water vapor penetration is provided to cover the periphery of an electronic device such as a solid-state battery, it is also possible to suppress the penetration of water vapor into the electronic device such as the solid-state battery. In other words, the packaging material itself can function as a water vapor barrier film.

[0019] Furthermore, in one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer located therebetween can be bonded to each other without necessarily using an adhesive layer, which also makes it possible to reduce the overall thickness of the packaging material. That is, when the packaging material is integrated with an electronic device such as a battery, this can contribute to reducing the size of the integrated product itself. Reducing the size of the integrated product itself can contribute to, for example, improving energy density or saving space.

[0020] Furthermore, in one embodiment of the present invention, the adhesive layer does not necessarily have to be used, so the adhesive layer application step and the adhesive layer curing step can be omitted. Therefore, the packaging material of one embodiment of the present invention can be a low-cost packaging material.

[0021] The components of the exterior material according to one embodiment of the present invention will be specifically described below.

[0022] [Metal layer] As shown in FIG. 1, the metal layer 11b is a layer positioned as an intermediate layer among the layers constituting the packaging material 11. In other words, the metal layer 11b is a layer sandwiched between the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c. The metal layer 11b is a layer extending in a planar shape. As a layer extending in a planar shape, the metal layer 11b has two main surfaces. Specifically, the metal layer 11b extends so that the first main surface of the metal layer 11b faces the second main surface of the metal layer 11b. The metal layer 11b used in the packaging material 11 may be, for example, a metal foil. The metal layer 11b may be a layer that is substantially impermeable to water vapor and / or gases, etc.

[0023] [First thermoplastic resin layer] As shown in FIG. 1 , the first thermoplastic resin layer 11a is located on the first principal surface of the metal layer 11b. In other words, the first thermoplastic resin layer 11a is located on the first principal surface of the metal layer 11b. Here, "located" may mean that the first thermoplastic resin layer 11a is provided in direct contact with the metal layer 11b, or that the first thermoplastic resin layer 11a is provided indirectly on the first principal surface via another layer. In other words, it means that another layer may or may not be present between the first thermoplastic resin layer 11a and the metal layer. The first thermoplastic resin layer 11a is used to protect the electronic device, specifically, to prevent the intrusion of water vapor from the outside (water vapor barrier layer) or to prevent damage to the electronic device. If necessary, the first thermoplastic resin layer 11a may also have chemical resistance, insulating properties, etc.

[0024] The first thermoplastic resin layer 11a is a layer containing a thermoplastic resin as a main component. The thermoplastic resin is a resin that can be bonded to an adherend such as a metal layer by applying heat. The thermoplastic resin is also a resin that softens by applying heat and hardens by cooling, and can reversibly repeat softening and hardening. The first thermoplastic resin layer 11a may be made only of a thermoplastic resin. The first thermoplastic resin layer 11a may be made of a single layer, or may be composed of an integrated body consisting of two or more layers. The thermoplastic resin may be a resin that has thermal fusion properties.

[0025] The melting point of the first thermoplastic resin layer 11a is preferably higher than 260°C. In the present invention, the "melting point of the first thermoplastic resin layer" may be, for example, the temperature at which the first thermoplastic resin layer 11a melts, or may be a melting point described in detail below. Furthermore, when the first thermoplastic resin layer 11a consists of two or more layers, the melting points of the materials used in these layers are preferably higher than 260°C.

[0026] [Second thermoplastic resin layer] As shown in FIG. 1 , the second thermoplastic resin layer 11c is located on the second principal surface of the metal layer 11b. In other words, the second thermoplastic resin layer 11c is located on the second principal surface of the metal layer 11b. The second thermoplastic resin layer 11c is located on a principal surface of the metal layer 11b different from the principal surface on which the first thermoplastic resin layer 11a is located. Here, "located" may mean that the second thermoplastic resin layer 11c is provided in direct contact with the metal layer 11b, or that the second thermoplastic resin layer 11c is provided indirectly on the second principal surface via another layer. In other words, another layer may or may not be provided between the second thermoplastic resin layer 11c and the metal layer 11b. The second thermoplastic resin layer 11c is used to protect the electronic device, specifically, to prevent water vapor from entering from the outside (water vapor barrier layer) or to prevent damage to the electronic device. If necessary, the second thermoplastic resin layer 11c may also have chemical resistance, insulating properties, and the like.

[0027] The second thermoplastic resin layer 11c is a layer containing a thermoplastic resin as a main component. The thermoplastic resin used for the second thermoplastic resin layer 11c is the same as the first thermoplastic resin. layer The second thermoplastic resin layer 11c is a resin having the same characteristics as the thermoplastic resin used in the above. The second thermoplastic resin layer 11c may be made of only a thermoplastic resin. The second thermoplastic resin layer 11c may be a single layer, or may be an integrated body made of two or more layers.

[0028] The melting point of the second thermoplastic resin layer 11c is preferably higher than 260°C. In the present invention, the "melting point of the second thermoplastic resin layer" may be, for example, the temperature at which the second thermoplastic resin layer 11c melts, or may be a melting point described in detail below. Furthermore, when the second thermoplastic resin layer 11c is made up of two or more layers, the melting points of the materials used in these layers are preferably higher than 260°C.

[0029] The melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be values ​​measured by a conventional method, for example, values ​​determined in accordance with the method described in JIS K7121-2012.

[0030] The melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c can be controlled by a conventional method, for example, by adjusting the molecular weight, degree of polymerization, molecular weight distribution, crystallinity, copolymerization ratio, and size of polymer crystals of the polymers constituting the thermoplastic resin.

[0031] The melting point of the first thermoplastic resin layer 11a is not particularly limited as long as it does not melt at the mounting temperature when an electronic device including the packaging material of the present invention is mounted on a substrate or the like. To further prevent the first thermoplastic resin layer 11a from melting at the mounting temperature, the melting point of the first thermoplastic resin layer 11a is preferably 270°C or higher, more preferably 280°C or higher, and even more preferably 290°C or higher. On the other hand, if the melting point of the first thermoplastic resin layer 11a is too high, the first thermoplastic resin layer 11a becomes difficult to soften and process, and a high-temperature heat source is required, increasing manufacturing costs. To improve processability and / or reduce manufacturing costs, the melting point of the first thermoplastic resin layer 11a may be preferably 400°C or lower, more preferably 370°C or lower, even more preferably 350°C or lower, and particularly preferably 330°C or lower.

[0032] The melting point of the second thermoplastic resin layer 11c is not particularly limited as long as it does not melt at the mounting temperature when an electronic device including the packaging material of the present invention is mounted on a substrate or the like. To further prevent the second thermoplastic resin layer 11c from melting at the mounting temperature, the melting point of the second thermoplastic resin layer 11c is preferably 270°C or higher, more preferably 280°C or higher, and even more preferably 290°C or higher. On the other hand, if the melting point of the second thermoplastic resin layer 11c is too high, the second thermoplastic resin layer 11c becomes difficult to soften and process, and a high-temperature heat source is required, resulting in high manufacturing costs. To improve processability or reduce manufacturing costs, the melting point of the second thermoplastic resin layer 11c may be preferably 400°C or lower, more preferably 370°C or lower, even more preferably 350°C or lower, and particularly preferably 330°C or lower.

[0033] From the viewpoint of further reducing the size of the integrated product obtained when the exterior material is integrated with an electronic device such as a battery, the thickness of the exterior material 11 is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm or less, even more preferably 10 μm or more and 200 μm or less, and particularly preferably 20 μm or more and 150 μm or less. below It may be.

[0034] The thickness of metal layer 11b may be, for example, 1 μm or more and 200 μm or less. From the viewpoint of further reducing the total thickness of packaging material 11, the thickness of metal layer 11b may be 1 μm or more and 100 μm or less, preferably 10 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, and even more preferably 20 μm or more and 50 μm or less.

[0035] From the viewpoint of further reducing the overall thickness of the exterior packaging material 11, the thickness of the first thermoplastic resin layer 11a may be preferably 1 μm or more and 500 μm or less, more preferably 2 μm or more and 300 μm or less, and even more preferably 3 μm or more and 100 μm or less.

[0036] From the viewpoint of further reducing the overall thickness of the exterior packaging material 11, the thickness of the second thermoplastic resin layer 11c may be preferably 1 μm or more and 500 μm or less, more preferably 2 μm or more and 300 μm or less, and even more preferably 3 μm or more and 100 μm or less.

[0037] The packaging material 11 according to one embodiment of the present invention may have another layer between the metal layer 11b and the first thermoplastic resin layer 11a located on the first main surface side of the metal layer 11b, and may have a further layer between the metal layer 11b and the second thermoplastic resin layer 11c located on the second main surface side of the metal layer 11b. Such another layer and further layer may be, for example, a water vapor barrier layer, an insulating layer, a chemical-resistant layer, a heat-resistant layer, or a damage prevention layer.

[0038] The exterior packaging material 11 according to one embodiment of the present invention may include a first sublayer covering the first thermoplastic resin layer 11a and a second sublayer covering the second thermoplastic resin layer 11c. Specifically, the first sublayer may be located on a major surface of the first thermoplastic resin layer 11a that is different from the major surface of the first thermoplastic resin layer 11a that faces or contacts the first major surface of the metal layer 11b. In such an embodiment, the first thermoplastic resin layer is located between the first sublayer and the metal layer. The second sublayer may be located on a major surface of the second thermoplastic resin layer 11c that is different from the major surface of the second thermoplastic resin layer 11c that faces or contacts the second major surface of the metal layer 11b. In such an embodiment, the second thermoplastic resin layer is located between the second sublayer and the metal layer. Such first and second sublayers may be, for example, additional water vapor barrier layers, chemical-resistant layers, heat-resistant exterior packaging materials, or damage-resistant layers. Specifically, it may be, for example, an additional metal layer or a metal plating layer formed by sputtering or the like.

[0039] As described above, the packaging material 11 according to one embodiment of the present invention may not use an adhesive layer or may use a relatively thin adhesive layer in order to suppress the penetration of water vapor. When an adhesive layer is not used, there is no risk of water vapor penetrating through the adhesive layer, thereby improving the water vapor barrier properties of the packaging material. Furthermore, by using a material with a melting point higher than 260°C, a packaging that can withstand solder mounting can be provided. When a relatively thin adhesive is used, the adhesive may be, for example, an adhesive that can maintain its adhesive strength before and after the mounting process.

[0040] The packaging material according to one embodiment of the present invention may have the following configuration.

[0041] In one embodiment of the present invention, at least one of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be directly bonded to the metal layer 11b.

[0042] thermoplastic sex tree The direct bonding between the oil layer and the metal layer 11b means that the oil layer and the metal layer 11b are bonded together by thermoplastic bonding. sex tree No other layer is interposed between the oil layer and the metal layer 11b, and the thermoplastic resin This means that the layer and the metal layer 11b are directly bonded to each other. sex tree No adhesive layer is interposed between the oil layer and the metal layer 11b, and the thermoplastic sex tree The thermoplastic resin layer 11a and the metal layer 11b may be directly bonded to each other. Here, "bonding" means, for example, that when two objects are in contact with each other, the two objects will not separate unless an external force is applied to the two objects. The directly bonded layers may be, for example, the first thermoplastic resin layer 11a and the metal layer 11b directly bonded to each other, or the second thermoplastic resin layer 11c and the metal layer 11b directly bonded to each other. From the viewpoint of further suppressing the penetration of water vapor, both the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be directly bonded to the metal layer 11b.

[0043] The direct bonding between the thermoplastic resin layer and the metal layer 11b may be achieved, for example, by pressure-bonding the thermoplastic resin layer and the metal layer 11b. Pressure-bonding refers to bonding the thermoplastic resin layer and the metal layer 11b by applying pressure or compression to at least one of the thermoplastic resin layer and the metal layer 11b. For example, pressure-bonding may be achieved by overlapping the first thermoplastic resin layer 11a and the metal layer 11b and applying a force to sandwich the overlapping first thermoplastic resin layer 11a and the metal layer 11b. The pressure-bonding between the second thermoplastic resin layer 11c and the metal layer 11b may also be achieved by a method similar to that described above. When directly bonding the thermoplastic resin layer and the metal layer 11b, an adhesive layer need not be used. The thermoplastic resin layer used in the exterior material is inherently adhesive. Therefore, the thermoplastic resin layer and the metal layer 11b can be bonded without using an adhesive layer. The mechanism by which the thermoplastic resin layer itself has bonding strength is not clear, but it is thought that factors include, for example, a molecular structure contained in the thermoplastic resin that contributes to bonding strength, or functional groups in the molecule, or the thermoplastic resin penetrating into the fine irregularities of the adherend.

[0044] The difference between the melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be 20°C or more. Specifically, the melting point of the first thermoplastic resin layer 11a may be 20°C or more higher than the melting point of the second thermoplastic resin layer 11c, or the melting point of the first thermoplastic resin layer 11a may be 20°C or more lower than the melting point of the second thermoplastic resin layer 11c. When the difference between the melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c is 20°C or more, the packaging material 11 is easier to manufacture. Specifically, in the manufacturing method of the packaging material 11 described below, it becomes possible to thermally laminate a thermoplastic resin layer with a relatively high melting point on the first main surface side of the metal layer 11b, and then thermally laminate a thermoplastic resin layer with a relatively low melting point on the second main surface side of the metal layer 11b.

[0045] The difference between the melting point of first thermoplastic resin layer 11a and the melting point of second thermoplastic resin layer 11c may be preferably 25°C or more, more preferably 30°C or more, even more preferably 35°C or more, and particularly preferably 40°C or more, from the viewpoint of facilitating the production of packaging material 11. On the other hand, from the viewpoint of facilitating temperature control during thermal lamination and / or cooling in the production of packaging material 11, the difference between the melting point of first thermoplastic resin layer 11a and the melting point of second thermoplastic resin layer 11c may be 100°C or less, preferably 80°C or less, more preferably 70°C or less, even more preferably 60°C or less, and particularly preferably 50°C or less.

[0046] The types of metal layer, first thermoplastic resin, and second thermoplastic resin that can be used in the exterior packaging material according to one embodiment of the present invention will be described in detail below.

[0047] [Metal layer type] The metal material constituting the metal layer 11b can be, for example, at least one selected from the group consisting of aluminum (or its alloy), stainless steel, copper, nickel, titanium, nickel-plated steel sheet, etc. Commercially available metal products can be used for the metal layer 11b.

[0048] When aluminum (or its alloy) is used for the metal layer 11b, for example, a conventionally used aluminum material may be used. When an aluminum alloy is used for the metal layer 11b, for example, an aluminum alloy having a composition specified in JIS A8021 or JIS 8079 may be used.

[0049] [Types of first thermoplastic resin layer and second thermoplastic resin layer] The thermoplastic resin used for the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c is not particularly limited as long as it has a melting point exceeding 260°C. For example, it may be a liquid crystal polymer, an aromatic polyester resin (e.g., polyethylene naphthalate), an aromatic polyether ketone resin, a fluorine-based resin, a polyphenylene sulfide resin, a polyamide resin, a thermoplastic polyimide resin, a polyamideimide resin, a polyetherimide resin, a phenolic resin, an acrylic resin, a polyurethane resin, a silicone resin, or a modified version thereof. Resins classified as super engineering plastics may also be used. The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be a homopolymer or copolymer of the above resins. The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be made of the above resin alone or may be a compound product composed of a combination of two or more resins. The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be a single layer or may be composed of two or more layers. Commercially available products can be used as the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c.

[0050] Of the above resins, from the viewpoint of further suppressing the penetration of water vapor, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be made of at least one resin selected from the group consisting of liquid crystal polymer, polyethylene naphthalate, aromatic polyether ketone-based resin, fluorine-based resin, polyamide-based resin, and polyphenylene sulfide-based resin.

[0051] Liquid crystal polymers include thermotropic liquid crystal polymers that exhibit liquid crystallinity in a molten state and rheotropic liquid crystal polymers that exhibit liquid crystallinity in a solution state. Either liquid crystal polymer may be used in the present invention, but a thermotropic liquid crystal polymer may also be used from the viewpoint of further suppressing the penetration of water vapor and / or preventing melting at the reflow temperature.

[0052] Among thermotropic liquid crystal polymers, thermotropic liquid crystal polyesters (hereinafter simply referred to as "liquid crystal polyesters") are aromatic polyesters obtained by reacting, for example, aromatic hydroxycarboxylic acids as essential monomers with monomers such as aromatic dicarboxylic acids and aromatic diols, and exhibit liquid crystallinity when melted. Representative examples include Type I [formula (1)] synthesized from parahydroxybenzoic acid (PHB), phthalic acid, and 4,4'-biphenol, Type II [formula (2)] synthesized from PHB and 2,6-hydroxynaphthoic acid, and Type III [formula (3)] synthesized from PHB, terephthalic acid, and ethylene glycol.

[0053] [ka]

[0054] The liquid crystal polymer used for the exterior material may be, among the above, type I liquid crystal polyester and type II liquid crystal polyester, since they have superior heat resistance and hydrolysis resistance.

[0055] The aromatic polyester resin has a basic skeleton of an aromatic dicarboxylic acid component and a glycol component. In the present invention, an aromatic polyester resin having a basic skeleton of a naphthalenedicarboxylic acid component and an alkylene glycol component may be used, and specifically, polyethylene naphthalate may be used. As the polyethylene naphthalate, a polyethylene naphthalate obtained by reacting 2,6-naphthalenedicarboxylic acid or 2,7-naphthalenedicarboxylic acid as the naphthalenedicarboxylic acid component with ethylene glycol as the alkylene glycol component may be used.

[0056] An aromatic polyetherketone resin is a resin having a structure in which a ketone group and an ether group are linked to an aromatic ring. There are various types of aromatic polyetherketone resins depending on the order and number of aromatic rings, ketone groups, and ether groups in their constituent repeating units, and any aromatic polyetherketone resin may be used. Specifically, in the present invention, for example, polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyaryletherketone (PAEK), or polyetherketoneetherketoneketone (PEKEKK) may be used as the aromatic polyetherketone resin.

[0057] Fluorine-based resins are resins obtained by polymerizing olefins containing fluorine. Examples of fluorine-based resins that may be used include polyethylene terephthalate (PETF), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), and ethylene tetrafluoroethylene copolymer (ETFE).

[0058] Polyphenylene sulfide is a resin containing an aromatic ring and a sulfide bond in the structural repeating unit of the polymer. Polyphenylene sulfide is classified into a linear type, a cross-linked type, a semi-cross-linked type, etc., and any type may be used.

[0059] The polyamide resin is a resin having a basic skeleton of a diamine component and a carboxylic acid component, and containing an amide bond in the structural repeating unit of the polymer. In the present invention, the polyamide resin may be an aromatic polyamide resin having a relatively high melting point, or a high heat-resistant polyamide (HTPA) resin.

[0060] The resin used for the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be a crystalline resin or an amorphous resin. From the viewpoint of suppressing the penetration of water vapor, a crystalline resin that is generally difficult for water vapor to permeate may be used.

[0061] The first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may contain a filler. The filler may be, for example, carbon fiber, glass fiber, silica, talc, or inorganic particles. The filler may be contained in the first thermoplastic resin layer 11a at, for example, 50% by volume or less, and the filler may be contained in the second thermoplastic resin layer 11c at, for example, 50% by volume or less.

[0062] In an exterior packaging material according to one embodiment of the present invention, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be composed of the same type of thermoplastic resin. This configuration facilitates standardization of equipment for manufacturing the exterior packaging material 11, thereby contributing to improved manufacturing efficiency. The term "type" in "same type" refers to the type of polymer material determined based on the repeating units of the polymer molecular structure and / or the properties of the polymer material. For example, "the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are composed of the same type of thermoplastic resin" means that if a liquid crystal polymer exhibiting liquid crystallinity is selected as the first thermoplastic resin, then a liquid crystal polymer exhibiting liquid crystallinity is also selected as the second thermoplastic resin. For example, if an aromatic polyester-based resin, which is a polyester species containing an aromatic ring, is selected as the first thermoplastic resin, then an aromatic polyester-based resin, which is a polyester species containing an aromatic ring, is selected as the second thermoplastic resin. For example, when an aromatic polyetherketone-based resin, which is a polymer species containing an aromatic ring, an ether bond, and a ketone group, is selected as the first thermoplastic resin, this means that an aromatic polyetherketone-based resin, which is a polymer species containing an aromatic ring, an ether bond, and a ketone group, is selected as the second thermoplastic resin.

[0063] As long as the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same type of thermoplastic resin, the physical properties of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be different. For example, when the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same type of thermoplastic resin, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be different in thermal properties (e.g., melting point, coefficient of thermal expansion, thermal conductivity), mechanical properties (e.g., tensile strength, flexural strength, compressive strength), resistivity, chemical resistance, etc.

[0064] To further improve manufacturing efficiency, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be made of the same thermoplastic resin material. The term "same material" here refers to materials with the same repeating units in the polymer molecular structure. For example, if polyethylene naphthalate, which is composed of repeating units of naphthalenedicarboxylic acid and ethylene glycol, is selected as the first thermoplastic resin, the second thermoplastic resin will also be made of polyethylene naphthalate composed of the same repeating units. For example, if polyether ether ketone, which is composed of repeating units consisting of an ether bond, an ether bond, and a ketone group in this order, is selected as the first thermoplastic resin, the second thermoplastic resin will also be made of polyether ether ketone composed of the same repeating units.

[0065] As long as the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same thermoplastic resin material, the physical properties of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be different. For example, when the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are made of the same thermoplastic resin material, the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be different in thermal properties (e.g., melting point, coefficient of thermal expansion, thermal conductivity), mechanical properties (e.g., tensile strength, flexural strength, compressive strength), resistivity, chemical resistance, etc.

[0066] (Method of manufacturing the exterior material of the present invention) A method for producing an exterior packaging material according to one embodiment of the present invention will be described below. The method for producing an exterior packaging material according to one embodiment of the present invention mainly includes the following steps (i) and (ii) in this order (see FIG. 2).

[0067] (i) passing the metal layer 511b and the first thermoplastic resin material 511a between the first heating roll 401 and the first cooling roll 501 so that the first thermoplastic resin material 511a is positioned on the first main surface of the metal layer 511b; (ii) A step of passing the metal layer 511b and the first thermoplastic resin material through the second heating roll 402 and the second cooling roll 502 so that the second thermoplastic resin material 511c is positioned on the second main surface of the metal layer 511b.

[0068] First, the first thermoplastic resin material 511a is bonded to the first main surface of the metal layer 511b by a thermal lamination method. Specifically, the metal layer 511b and the first thermoplastic resin material 511a are passed between the first heating roll 401 and the first cooling roll 501 so that the first main surface of the metal layer 511b and the first thermoplastic resin material 511a overlap. At this time, the metal layer 511b is passed in contact with the first heating roll 401, and the first thermoplastic resin material 511a is passed in contact with the first cooling roll 501. As a result, the first thermoplastic resin material in the portion in contact with the heated metal layer 511b is heated. 5 The first thermoplastic resin material 511a is softened, and the softened first thermoplastic resin material 511a is bonded (thermally fused) to the metal layer 511b. Thereafter, an integrated product of the metal layer 511b and the first thermoplastic resin material 511a is obtained between the first heating roll 401 and the first cooling roll 501.

[0069] Next, the integrated product of the metal layer 511b and the first thermoplastic resin material 511a is subjected to thermal lamination to bond the second thermoplastic resin material 511c to the remaining second main surface of the metal layer 511b. Specifically, the metal layer 511b and the second thermoplastic resin material 511c are passed between the second heating roll 402 and the second cooling roll 502 so that the remaining second main surface of the metal layer 511b and the second thermoplastic resin material 511c overlap. As a result, the second thermoplastic resin material 511c in the portion in contact with the heated metal layer 511b softens, and the softened second thermoplastic resin material 511c is bonded (thermally fused) to the metal layer 511b. At this time, the metal layer 511b is passed in contact with the second heating roll 402, and the second thermoplastic resin material 511c is passed in contact with the second cooling roll 502. From between the second heating roll 402 and the second cooling roll 502, the packaging material 11 according to one embodiment of the present invention is obtained.

[0070] In the present invention, the melting point of the thermoplastic resin material that is heat-fused first is preferably at least 20°C higher than the melting point of the thermoplastic resin material that is heat-fused second. The thermoplastic resin material that is heat-fused first is referred to as the first thermoplastic resin material, and the thermoplastic resin material that is heat-fused second is referred to as the second thermoplastic resin material. In other words, the melting point of the first thermoplastic resin material is preferably higher than the melting point of the second thermoplastic resin material. More preferably, the melting point of the first thermoplastic resin material is at least 20°C higher than the melting point of the second thermoplastic resin material.

[0071] According to the above manufacturing method, when a relatively low-melting-point thermoplastic resin material is subsequently thermally laminated onto the second main surface of the metal layer 511b, the relatively high-melting-point thermoplastic resin material previously thermally laminated onto the first main surface of the metal layer 511b does not soften and can maintain adhesion to the metal layer. For this reason, it is possible to thermally laminate a relatively high-melting-point thermoplastic resin material onto the first main surface of the metal layer 511b, and then thermally laminate a relatively low-melting-point thermoplastic resin material onto the second main surface of the metal layer 511b. In the above embodiment, the first heating roll 401, which thermally laminates the metal layer and the resin material, is preferably at a higher temperature than the subsequent second heating roll 402.

[0072] When an adhesive layer is used, the adhesive layer may be provided in advance on the metal layer 511b and / or the thermoplastic resin layer. 。

[0073] The temperature of the first heating roll 401 is not particularly limited as long as it can thermally fuse the metal layer 511b and the first thermoplastic resin material 511a together, and may be, for example, 200°C or higher and 400°C or lower, preferably 200°C or higher and 350°C or lower, more preferably 230°C or higher and 350°C or lower, even more preferably 230°C or higher and 330°C or lower, and particularly preferably 230°C or higher and 310°C or lower.

[0074] The temperature of the second heating roll 402 is not particularly limited as long as it can thermally fuse the metal layer 511b and the second thermoplastic resin material 511c together, and may be, for example, 200°C or higher and 400°C or lower, preferably 200°C or higher and 350°C or lower, more preferably 230°C or higher and 350°C or lower, even more preferably 230°C or higher and 330°C or lower, and particularly preferably 230°C or higher and 310°C or lower.

[0075] [Electronic Devices] An electronic device to which an exterior material according to one embodiment of the present invention can be applied will be described below. While the description will be made with reference to the drawings as necessary, the contents shown in the drawings are merely shown schematically and exemplarily to facilitate understanding of the present invention, and the overall appearance, dimensional ratios, etc. may differ from the actual parts.

[0076] The electronic devices to which the packaging material according to one embodiment of the present invention can be applied are not particularly limited, except that they use the packaging material according to one embodiment of the present invention. Examples of electronic devices include circuit boards, composite modules, batteries, and electronic components. Examples of batteries include secondary batteries, particularly solid-state batteries. Examples of electronic components include capacitors, resistors, coils, diodes, filters, oscillators, and / or transistors. Electronic device elements other than the packaging material (for example, in the case of a battery, this refers to terminals, electrodes, separators, or electrolytes, and for example, in the case of a capacitor, this refers to electrodes, dielectrics, or terminals) are not particularly limited as long as they are applicable to electronic devices. For example, such electronic device elements may be those that have been used previously.

[0077] One embodiment of the present invention includes an electronic device and an exterior covering covering the electronic device, the exterior covering including a metal layer, a first thermoplastic resin layer positioned on a first main surface side of the metal layer, and a second thermoplastic resin layer positioned on a second main surface side of the metal layer, wherein the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C.

[0078] As described in the features of the packaging material, the packaging material according to one embodiment of the present invention can suppress the penetration of water vapor into the packaging material itself. As a result, when the packaging material with suppressed water vapor penetration is provided to cover the periphery of an electronic device, it is also possible to suppress the penetration of water vapor into the electronic device.

[0079] Furthermore, in one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer located therebetween can be bonded to each other without necessarily using an adhesive layer, which also makes it possible to reduce the overall thickness of the packaging material. That is, when the packaging material is integrated with an electronic component or electronic device, this can contribute to reducing the size of the integrated product itself. Reducing the size of the integrated product itself can contribute to space savings, etc.

[0080] Furthermore, in one embodiment of the present invention, since the adhesive layer is not necessarily used, the adhesive layer application process and adhesive layer curing process can be omitted. Furthermore, a solder-mountable electronic device can be provided without using an expensive ceramic package. Therefore, the electronic device of one embodiment of the present invention can be a low-cost electronic device.

[0081] [Solid battery] The following will take a battery, particularly a solid-state battery, of the above-mentioned electronic devices as an example, and describe in detail the application of an exterior material according to one embodiment of the present invention to the solid-state battery. Specifically, the exterior material is applied so as to cover the battery element of the solid-state battery. In this case, the internal battery element is protected from the external environment, and the solid-state battery as a whole can be in a packaged state. In other words, a solid-state battery with an exterior material can also be referred to as a solid-state battery package. Note that while FIGS. 3 to 12 schematically show a configuration in which a battery element 100 is covered with an exterior material according to one embodiment of the present invention, when the exterior material according to one embodiment of the present invention is applied to an electronic device other than a solid-state battery, the battery element 100 in the above figures can also be an electronic device element.

[0082] The solid-state battery to which the exterior material according to one embodiment of the present invention is applied is not particularly limited, except that the exterior material according to one embodiment of the present invention is used. Specifically, the battery elements other than the exterior material (e.g., electrodes, solid electrolyte, conductive parts, etc.) are not particularly limited as long as they are applicable to solid-state batteries. For example, such a battery element may be a conventionally used one.

[0083] (Basic structure of solid-state batteries) The basic structure of a solid-state battery is explained below. A solid-state battery comprises at least positive and negative electrode layers and a solid electrolyte. Specifically, a solid-state battery comprises battery elements including battery structural units each consisting of a positive electrode layer, a negative electrode layer, and a solid electrolyte interposed between them.

[0084] In the present invention, the term "solid-state battery" broadly refers to a battery whose components are made of solids, and more particularly refers to an all-solid-state battery whose battery components (particularly preferably all battery components) are made of solids. In a preferred embodiment, the solid-state battery of the present invention is a laminated solid-state battery in which each layer constituting a battery unit is stacked on top of each other, and preferably each such layer is made of a sintered body. Note that the term "solid-state battery" encompasses not only so-called "secondary batteries" that can be repeatedly charged and discharged, but also "primary batteries" that can only be discharged. According to a preferred embodiment of the present invention, the "solid-state battery" is a secondary battery. The term "secondary battery" is not limited to the name, and can also encompass, for example, an electricity storage device.

[0085] As used herein, "cross-sectional view" refers to a state when viewed from a direction approximately perpendicular to the thickness direction of the battery elements that constitute a solid-state battery. The "vertical direction" and "horizontal direction" used directly or indirectly in this specification correspond to the vertical direction and horizontal direction in the drawings, respectively. Unless otherwise specified, the same symbols or symbols indicate the same members or parts or have the same meaning. In a preferred embodiment, the vertical downward direction (i.e., the direction in which gravity acts) can be considered to correspond to the "downward direction," and the opposite direction can be considered to correspond to the "upward direction."

[0086] The layers constituting the solid-state battery may be formed by firing, and the positive electrode layer, negative electrode layer, solid electrolyte, etc. may form sintered layers. Preferably, the positive electrode layer, negative electrode layer, and solid electrolyte are each fired together, and therefore the battery elements may form an integrated sintered body.

[0087] The positive electrode layer is an electrode layer comprising at least a positive electrode active material. The positive electrode layer may further comprise a solid electrolyte. For example, the positive electrode layer is composed of a sintered body comprising at least positive electrode active material particles and solid electrolyte particles. In one embodiment, the positive electrode layer is composed of a sintered body comprising substantially only positive electrode active material particles and solid electrolyte particles. On the other hand, the negative electrode layer is an electrode layer comprising at least a negative electrode active material. The negative electrode layer may further comprise a solid electrolyte. For example, the negative electrode layer is composed of a sintered body comprising at least negative electrode active material particles and solid electrolyte particles. In one embodiment, the negative electrode layer is composed of a sintered body comprising substantially only negative electrode active material particles and solid electrolyte particles.

[0088] The positive electrode active material and the negative electrode active material are materials involved in the transfer of electrons in a solid-state battery. Charge and discharge are performed by transferring (conducting) ions between the positive electrode layer and the negative electrode layer via the solid electrolyte, transferring electrons. The positive electrode layer and the negative electrode layer may be layers capable of absorbing and releasing lithium ions or sodium ions in particular. In other words, the solid-state battery may be an all-solid-state secondary battery in which charging and discharging are performed by transferring lithium ions or sodium ions between the positive electrode layer and the negative electrode layer via the solid electrolyte.

[0089] (Cathode active material) The positive electrode active material contained in the positive electrode layer may be at least one selected from the group consisting of a lithium-containing phosphate compound having a Nasicon structure, a lithium-containing phosphate compound having an olivine structure, a lithium-containing layered oxide, and a lithium-containing oxide having a spinel structure. An example of a lithium-containing phosphate compound having a Nasicon structure is Li3V2(PO4)3. An example of a lithium-containing phosphate compound having an olivine structure is Li3Fe2(PO4)3, LiFePO4, and / or LiMnPO4. An example of a lithium-containing layered oxide is LiCoO2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3Examples of lithium-containing oxides having a spinel structure include LiMn2O4 and / or LiNi 0.5 Mn 1.5 O4, etc. The type of lithium compound is not particularly limited, but may be, for example, a lithium transition metal composite oxide or a lithium transition metal phosphate compound. Lithium transition metal composite oxide is a general term for oxides containing lithium and one or more transition metal elements as constituent elements, and lithium transition metal phosphate compound is a general term for phosphate compounds containing lithium and one or more transition metal elements as constituent elements. The type of transition metal element is not particularly limited, but may be, for example, cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe), etc.

[0090] In addition, the positive electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, sodium-containing layered oxides, and sodium-containing oxides having a spinel structure. For example, in the case of sodium-containing phosphate compounds, at least one selected from the group consisting of Na3V2(PO4)3, NaCoFe2(PO4)3, Na2Ni2Fe(PO4)3, Na3Fe2(PO4)3, Na2FeP2O7, Na4Fe3(PO4)2(PO2O7), and as a sodium-containing layered oxide, NaFeO2 may be used.

[0091] Alternatively, the positive electrode active material may be, for example, an oxide, a disulfide, a chalcogenide, or a conductive polymer. The oxide may be, for example, titanium oxide, vanadium oxide, or manganese dioxide. The disulfide may be, for example, titanium disulfide or molybdenum sulfide. The chalcogenide may be, for example, niobium selenide. The conductive polymer may be, for example, a disulfide, polypyrrole, polyaniline, polythiophene, polyparastyrene, polyacetylene, or polyacene.

[0092] (Negative electrode active material) The negative electrode active material contained in the negative electrode layer may be at least one selected from the group consisting of oxides containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb, and Mo, carbon materials such as graphite, graphite-lithium compounds, lithium alloys, lithium-containing phosphate compounds having a Nasicon structure, lithium-containing phosphate compounds having an olivine structure, and lithium-containing oxides having a spinel structure. An example of a lithium alloy is Li-Al. An example of a lithium-containing phosphate compound having a Nasicon structure is Li3V2(PO4)3 and / or LiTi2(PO4)3. An example of a lithium-containing phosphate compound having an olivine structure is Li3Fe2(PO4)3 and / or LiCuPO4. An example of a lithium-containing oxide having a spinel structure is Li4Ti5O. 12 etc.

[0093] In addition, the negative electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, and sodium-containing oxides having a spinel structure. In a preferred embodiment of the solid-state battery of the present invention, the positive electrode layer and the negative electrode layer may be made of the same material.

[0094] The positive electrode layer and / or the negative electrode layer may contain a conductive material, which may include at least one of metal materials such as silver, palladium, gold, platinum, aluminum, copper, and nickel, and carbon.

[0095] Furthermore, the positive electrode layer and / or the negative electrode layer may contain a sintering aid, such as at least one selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, boron oxide, silicon oxide, bismuth oxide, and phosphorus oxide.

[0096] In a preferred embodiment of the solid-state battery of the present invention, the positive electrode layer and the negative electrode layer are made of the same material. In the solid-state battery of the present invention, the positive electrode layer and the negative electrode layer may be made of the same material (for example, in such a case, the positive electrode active material and the negative electrode active material may be the same type).

[0097] (solid electrolyte) A solid electrolyte is a material capable of conducting lithium ions. In particular, the solid electrolyte constituting the battery constituent unit in a solid-state battery forms a layer capable of conducting lithium ions between the positive electrode layer and the negative electrode layer. The solid electrolyte only needs to be provided at least between the positive electrode layer and the negative electrode layer. In other words, the solid electrolyte may also be present around the positive electrode layer and / or the negative electrode layer so as to protrude from between the positive electrode layer and the negative electrode layer. Specific solid electrolytes may be oxide-based, for example, and examples thereof include lithium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, oxides having a garnet or garnet-like structure, oxide glass ceramic-based lithium ion conductors, etc. Examples of lithium-containing phosphate compounds having a Nasicon structure include Li x M y (PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga and Zr). An example of a lithium-containing phosphate compound having a Nasicon structure is Li 1.2 Al 0.2 Ti 1.8 (PO4)3, etc. An example of an oxide with a perovskite structure is La 0.55 Li 0.35 Examples of oxides with garnet or garnet-like structures include Li7La3Zr2O 12 Examples of oxide glass ceramic lithium ion conductors that can be used include a phosphate compound containing lithium, aluminum, and titanium as constituent elements (LATP) and a phosphate compound containing lithium, aluminum, and germanium as constituent elements (LAGP).

[0098] In addition, examples of solid electrolytes capable of conducting sodium ions include sodium-containing phosphate compounds with a Nasicon structure, oxides with a perovskite structure, oxides with a garnet structure or a garnet-like structure, etc. Examples of sodium-containing phosphate compounds with a Nasicon structure include NaxMy(PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga, and Zr).

[0099] The solid electrolyte may contain a sintering aid. The sintering aid contained in the solid electrolyte may be selected from the same materials as the sintering aids that may be contained in the positive electrode layer and the negative electrode layer, for example.

[0100] The thickness of the solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more and 15 μm or less, particularly 1 μm or more and 5 μm or less.

[0101] (Positive electrode current collecting layer and negative electrode current collecting layer) The positive electrode layer and the negative electrode layer may include a positive electrode current collecting layer and a negative electrode current collecting layer, respectively. The positive electrode current collecting layer and the negative electrode current collecting layer may each be in the form of a foil, but may also be in the form of a sintered body from the viewpoint of reducing the manufacturing cost of the solid-state battery by co-firing and reducing the internal resistance of the solid-state battery. The positive electrode current collecting layer and the negative electrode current collecting layer are preferably made of a material with high conductivity, such as silver, palladium, gold, platinum, aluminum, copper, or nickel. Copper, in particular, may be used because it is less likely to react with the positive electrode active material, the negative electrode active material, and the solid electrolyte material and is effective in reducing the internal resistance of the solid-state battery. When the positive electrode current collecting layer and the negative electrode current collecting layer are in the form of a sintered body, they may be made of a sintered body containing a conductive material and a sintering aid. The conductive material contained in the positive electrode current collecting layer and the negative electrode current collecting layer may be selected from, for example, the same materials as the conductive materials that can be contained in the positive electrode layer and the negative electrode layer. The sintering aid contained in the positive electrode current collecting layer and the negative electrode current collecting layer may be selected from, for example, the same materials as the sintering aids that may be contained in the positive electrode layer and the negative electrode layer. Note that the positive electrode current collecting layer and the negative electrode current collecting layer are not necessarily required for a solid-state battery, and a solid-state battery that does not include such a positive electrode current collecting layer and a negative electrode current collecting layer is also conceivable. In other words, the solid-state battery of the present invention may be a solid-state battery without a current collecting layer.

[0102] The thickness of the positive electrode layer and the negative electrode layer is not particularly limited, but may be, for example, independently 2 μm or more and 50 μm or less, particularly 5 μm or more and 30 μm or less.

[0103] Solid-state batteries, specifically battery elements, generally have terminals (e.g., external electrodes). In particular, end electrodes are provided on the side surfaces of the battery element. More specifically, a positive end electrode connected to the positive electrode layer and a negative end electrode connected to the negative electrode layer are provided. Such end electrodes may be made of a material with high electrical conductivity. Specific materials for the end electrodes are not particularly limited, but include at least one selected from the group consisting of silver, gold, platinum, aluminum, copper, tin, and nickel. Furthermore, a terminal called a tab lead is provided at the end of the end electrode, which extracts generated electricity to the outside. Like the end electrodes, the material for the tab lead may also be made of a material with high electrical conductivity. Specific materials for the tab lead are not particularly limited, but include at least one selected from the group consisting of silver, gold, platinum, aluminum, copper, tin, and nickel.

[0104] (Characteristics of the solid-state battery of the present invention) A solid-state battery to which the packaging material according to one embodiment of the present invention can be applied may include a battery element including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, a packaging material covering the battery element, and a conductive part capable of extracting electricity from the battery element to the outside. The packaging material includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer, and is characterized in that the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C, i.e., the packaging material of the present invention described above.

[0105] As described in the characteristics of the above-mentioned packaging material, the packaging material according to one embodiment of the present invention can suppress the penetration of water vapor into the packaging material itself. As a result, when the packaging material that suppresses the penetration of water vapor is provided so as to cover the periphery of a solid-state battery, it is also possible to suppress the penetration of water vapor into the solid-state battery.

[0106] Furthermore, in one embodiment of the present invention, two thermoplastic resin layers and an adherend such as a metal layer located therebetween can be bonded to each other without necessarily using an adhesive layer, which also makes it possible to reduce the overall thickness of the exterior material. That is, when the exterior material is provided integrally with the solid-state battery, this can contribute to reducing the size of the integrated product itself. Reducing the size of the integrated product itself can contribute to space savings, etc.

[0107] Furthermore, in one embodiment of the present invention, the adhesive layer is not necessarily used, so the adhesive layer application step and the adhesive layer curing step can be omitted. Therefore, the solid-state battery of one embodiment of the present invention can be a low-cost solid-state battery.

[0108] The form in which the exterior material covers the solid-state battery is not particularly limited, and any conventional form may be used. Regardless of the form, the solid-state battery obtained by integrating the exterior material and the battery element can exhibit the above-mentioned effects of the present invention. The form in which the exterior material of the present invention covers the battery element may be, for example, the following embodiment.

[0109] The first embodiment is an embodiment in which the exterior material is made of a continuous single structure, and the single structure exterior material surrounds the battery element, as shown in Figures 3 and 4. The second embodiment is an embodiment in which the exterior material is an exterior composite made of a first exterior material and a second exterior material, and the exterior composite surrounds the battery element, as shown in Figures 5 to 12.

[0110] <First embodiment> Fig. 3 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the present invention, and Fig. 4 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the present invention.

[0111] From the viewpoint of surface mounting a solid-state battery, for example, an embodiment such as that shown in Fig. 3 may be adopted. Fig. 3 shows a solid-state battery 200 in which a battery element 100 is covered with a single exterior material 11 and has a conductive part 20 consisting of an end electrode 21 and a tab lead 22. The end electrode 21 is connected to one end of the tab lead 22, and the other end of the tab lead 22 is exposed to the outside. The solid-state battery 200 in Fig. 3 can be surface mounted on a substrate via the exposed end of the tab lead 22.

[0112] 4, the conductive portion 20 (tab lead 22) may be drawn out to the outside, and the tab lead 22 of the drawn conductive portion 20 may be provided along the contour surface of the battery element 100. In other words, the tab lead 22 of the conductive portion 20 and the outer casing 11 may be provided along the contour surface of the battery element 100.

[0113] In this specification, the "contour surface of the battery element 100" refers to the surface that forms the shape or appearance of the battery element 100. In this specification, the "tab lead 22 of the conductive part 20 and the outer casing 11 are provided along the contour surface of the battery element 100" refers to a state in which the tab lead 22 of the conductive part 20 and the outer casing 11 are provided approximately parallel to the extension direction of the contour surface of the battery element 100.

[0114] That is, the tab lead 22 of the conductive portion 20 and the outer casing 11 may extend in approximately the same direction as the extension direction of the contoured surface of the battery element 100. In this specification, the "extension direction of the contoured surface of the battery element 100" means the direction in which the contoured surface extends longitudinally. The conductive portion 20 and the outer casing 11 only need to extend in approximately the same direction as the extension direction of the contoured surface of the battery element 100 at least at a glance, and the conductive portion 20 and the outer casing 11 do not necessarily need to extend in exactly the same direction as the extension direction of the contoured surface of the battery element 100. For example, due to the relative positions of the conductive portion 20, the outer casing 11, and the battery element 100, there may be portions where a part of the conductive portion 20 and a part of the outer casing 11 do not extend approximately coaxially with the extension direction of the contoured surface of the battery element 100.

[0115] By forming the tab lead 22 of the conductive part 20 to follow the contour of the battery element 100, the contact area between the conductive part 20 and the substrate of the solid-state battery 200 shown in Fig. 4 can be increased during surface mounting. If the contact area between the conductive part 20 and the substrate is large, the solid-state battery 200 can be more firmly surface mounted to the substrate.

[0116] In one embodiment, the portion of conductive portion 20 drawn out (corresponding to tab lead 22) may include bent portion 20A. The bent portion here refers to a bent portion. There are no particular limitations on the form of the bend; for example, as shown in FIG. 4 , in a form in which conductive portion 20 is composed of end surface electrode 21 and tab lead 22, the bent portion is also defined as a bent portion even if the portion of conductive portion 20 drawn out has a right-angled portion. Alternatively, the portion of conductive portion 20 drawn out may be bent so as to have an arc (curved) portion, and specifically, may be bent so as to follow the surface of outer jacket material 11.

[0117] The portion of the conductive part 20 drawn out to the outside (corresponding to the tab lead 22) is connected to an electronic substrate or the like when the solid-state battery 200 according to one embodiment of the present invention is surface-mounted. In this case, the portion of the conductive part 20 drawn out to the outside (corresponding to the tab lead 22) can be bent depending on the mounting area of ​​the solid-state battery 200 according to one embodiment of the present invention, the positional relationship between the solid-state battery 200 and the electronic substrate or the like, and the method of connecting the solid-state battery 200 and the electronic substrate or the like.

[0118] The length of the conductive portion 20 drawn out to the outside is not particularly limited as long as electricity can be extracted from the conductive portion 20. The conductive portion 20 (specifically, the tab lead 22) that follows the contour of the battery element 100 may have its end provided on the upper or lower surface of the solid-state battery 200, for example, on the lower surface. This allows the solid-state batteries 200 to be mounted in a row on the electronic substrate, thereby reducing the overall surface mounting area. Furthermore, from the perspective of reducing the overall surface mounting area and more reliably achieving surface mounting of the solid-state batteries 200, at least a portion of the drawn-out portion of the conductive portion 20 may be in "surface" contact with the surface of the electronic substrate. This "surface" contact increases the contact area between the conductive portion 20 and the electronic substrate. This configuration can be achieved by providing a bent portion in the drawn-out portion of the conductive portion 20 so that at least a portion of the drawn-out portion of the conductive portion 20 is approximately parallel to the surface of the electronic substrate, as shown in FIG. 4 .

[0119] The drawn-out end of the conductive portion 20 does not necessarily need to be fixed to the exterior material 11, and may be a free end that is freely movable. In this regard, from the viewpoint of reducing the mounting area, in one embodiment, at least the drawn-out end of the conductive portion 20 may be fixed to the exterior material 11.

[0120] By adopting such a configuration, the drawn-out end of the conductive part 20 can be brought into close contact with the side surface of the battery element 100 and can maintain this close contact state.

[0121] Furthermore, by maintaining the above-described tight contact state, it is possible to suitably prevent the end of the drawn-out conductive portion 20 from being bent or deformed when an external force is applied to the end of the drawn-out conductive portion 20. As a result, the solid-state battery 200 can be suitably surface-mounted on the electronic substrate.

[0122] The method for fixing the end of the drawn-out conductive portion 20 to the exterior material 11 is not particularly limited. For example, the end of the drawn-out conductive portion 20 may be fixed to the exterior material 11 by heat fusion. For example, the end of the drawn-out conductive portion 20 may be fixed to the exterior material 11 using an adhesive. The adhesive may be in the form of, for example, liquid, paste, sheet, solid, or powder. The type of adhesive may be, for example, a water-based adhesive, a chemical reaction adhesive, a solvent-based adhesive, or a hot melt adhesive. There is no particular limit to the adhesive as long as the adhesive strength of the adhesive does not change before and after the reflow process. . contact The adhesive material may be at least one selected from the group consisting of silicone resins, acrylic resins, epoxy resins, and urethane resins.

[0123] Furthermore, during charging and discharging of the solid-state battery 200, ions move through the solid electrolyte layer between the positive electrode layer and the negative electrode layer, causing the active material contained in each electrode layer to expand and contract along the stacking direction. In particular, expansion of the active material, i.e., the electrode layers, along the stacking direction generates tensile stress acting upward and tensile stress acting downward. In this regard, according to this embodiment, when the solid-state battery 200 is surface-mounted on an electronic substrate, a small space can be formed between the solid-state battery 200 and the electronic substrate. The presence of such a space makes it possible to accommodate the expanding portion of the solid-state battery 200 due to the expansion of the electrode layers along the stacking direction.

[0124] The sheath material 11 may be fixed to the end surface electrode 21 by heat fusion. Specifically, the first thermoplastic resin layer 11a or the second thermoplastic resin layer 11b of the sheath material 11 may be fixed to the end surface electrode 21 by heat fusion. plasticity Alternatively, the thermoplastic resin layer 11c may be heat-sealed to the end electrode 21. In this case, the difference between the melting point of the first thermoplastic resin layer 11a and the melting point of the second thermoplastic resin layer 11c may be 20°C or more. In this embodiment, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a. By adopting this embodiment, it becomes easier to heat-seal only the second thermoplastic resin layer 11c, which has a relatively low melting point, to the end electrode 21.

[0125] <Second embodiment> From the viewpoint of surface mounting the solid-state battery, for example, an embodiment as shown in Fig. 5 may be adopted. Specifically, the solid-state battery shown in Fig. 5 has the following features: An exterior composite consisting of two or more exterior materials is provided, the two or more exterior materials including a first exterior material and a second exterior material, and the first exterior material and the second exterior material form an overlapping region where they overlap each other; A conductive portion is drawn out from the overlapping region to the outside.

[0126] FIG. 5 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing an aspect of preventing water vapor penetration by a solid-state battery according to one embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the present invention. FIG. 8 is a perspective view schematically showing a solid-state battery according to one embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing a solid-state battery (expanded state) according to one embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing a solid-state battery according to one embodiment of the present invention (with sealant). FIG. 11 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the present invention. FIG. 12 is a cross-sectional view schematically showing a solid-state battery according to another embodiment of the present invention. in be.

[0127] As used herein, the term "armor composite" refers to a structure (composition) formed by assembling or combining two or more armor materials, and may also be referred to as an armor assembly. As used herein, "composite" refers to a state in which two or more elements are combined into one. As used herein, the term "conductive portion" refers collectively to components that contribute to electrical extraction, such as the end surface electrodes 21 provided on the battery element 100 and the tab leads 22 connected to the end surface electrodes 21. In other words, the conductive portion 20 comprises the end surface electrodes 21 provided on the battery element 100 and the tab leads 22 connected to the end surface electrodes 21.

[0128] That is, in one embodiment of the present invention, the battery element 100 is covered with an exterior composite 10 formed by combining two or more exterior materials. In other words, the exterior composite 10 surrounds the battery element 100. As an example, as shown in FIG. 5 , the exterior composite 10 is composed of a first exterior material 11 and a second exterior material 12. Furthermore, in one embodiment of the present invention, an overlap region 50 is formed in the exterior composite 10, where the first exterior material 11 and the second exterior material 12 overlap each other, and a conductive portion 20 is drawn out from the overlap region 50 to the outside.

[0129] First exterior packaging material 11 includes metal layer 11b, first thermoplastic resin layer 11a, and second thermoplastic resin layer 11c. Second exterior packaging material 12 includes metal layer 12b, first thermoplastic resin layer 12a, and second thermoplastic resin layer 12c. The layers constituting first exterior packaging material 11 and the layers constituting second exterior packaging material 12 may be the same.

[0130] It should be noted that, in the overlap region 50, the positional relationship between the first exterior material 11 and the second exterior material 12 is not particularly limited. For example, the second exterior material 12 may be positioned outside the first exterior material 11, or the first exterior material 11 may be positioned outside the second exterior material 12. In other words, in the overlap region 50, the first exterior material 11 may be provided on a side relatively closer to the battery element 100, and the second exterior material 12 may be provided on a side relatively more distal to the battery element 100. Alternatively, in the overlap region 50, the second exterior material 12 may be provided on a side relatively closer to the battery element 100, and the first exterior material 11 may be provided on a side relatively more distal to the battery element 100. The overlap region 50 may be composed of more than two exterior materials. For example, in the embodiment shown in Figure 5, the overlapping region 50 is composed of two layers, a first exterior material 11 and a second exterior material 12, but the overlapping region may also be composed using, for example, a third exterior material and a fourth exterior material.

[0131] As used herein, the term "overlapping region" broadly refers to the region where the first and second sheathing materials 11 and 12 overlap, and narrowly refers to the region where a portion of the first and second sheathing materials 11 and 12 overlap. "Mutually overlapping" refers to a state in which the main surface of one sheathing material and the main surface of the other sheathing material face each other directly or adjacently. In other words, even if a resin, metal, or the like is interposed between the main surface of one sheathing material and the main surface of the other sheathing material, the above state is considered to be "mutually overlapping." As used herein, "water vapor" is not limited to gaseous water but also includes liquid water. In other words, the term "water vapor" is used to broadly encompass anything related to water, regardless of its physical state. Therefore, "water vapor" can also be referred to as moisture, and liquid water in particular can include condensed water resulting from condensation of gaseous water.

[0132] As used herein, "pulled out" means that at least a portion of an independent component located within another component extends from the component to the outside, and at least a portion of the independent component is exposed to the outside. That is, as used herein, "conductive portion 20 is pulled out from overlapping region 50 of exterior composite 10 to the outside" refers to a state in which a portion of conductive portion 20 that can be electrically connected to battery element 100 covered by exterior composite 10 passes between first exterior material 11 and second exterior material 12 that form overlapping region 50 of exterior composite 10, as shown in FIG. 5 .

[0133] As shown in FIG. 5 , the first exterior material 11, which is a component of the exterior composite 10, does not need to cover the entire battery element 100, and similarly, the second exterior material 12 does not need to cover the entire battery element 100. Ultimately, the first exterior material 11 and the second exterior material 12 only need to be arranged so that they cover the entire battery element 100. That is, ultimately, the exterior composite 10 only needs to be arranged so that it covers the entire battery element 100. Also, as shown in FIG. 5 , the overlap region 50 can be formed so that a portion of one exterior material and a portion of the other exterior material cover each other. In other words, the overlap region 50 can be formed by stacking a portion of the first exterior material 11 and a portion of the second exterior material 12 on top of each other. The direction in which the first and second exterior materials are stacked in the overlapping region 50 is approximately perpendicular to the stacking direction of the positive electrode layer 110, the negative electrode layer 120, and the solid electrolyte layer 130 in the battery element 100. The direction in which the conductive portion 20 is drawn out from the overlapping region 50 is approximately perpendicular to the stacking direction of the first and second exterior materials in the overlapping region 50, while being approximately parallel to the stacking direction of the positive electrode layer 110, the negative electrode layer 120, and the solid electrolyte layer 130 in the battery element 100. With this configuration, as in the solid-state battery 200 of FIG. 5 , the first exterior material 11 can be interposed between the battery element 100 and most of the tab lead 22 constituting the conductive portion 20, excluding the connection portion with the end surface electrode 21. In other words, the tab lead 22 can be connected to the end surface electrode 21 while being separated from the battery element 100 by the first exterior material.

[0134] As described above, the solid state battery 200 according to one embodiment of the present invention employs a configuration in which the conductive portion 20 is drawn out from the overlap region 50 of the armor composite 10. This configuration can achieve the following technical effects.

[0135] Water vapor penetration into a battery element may cause deterioration of battery characteristics. Water vapor penetration into the battery element can be suppressed by covering the battery element with an exterior material that acts as a water vapor permeation prevention layer. In this regard, as shown in FIGS. 16 and 17 , a conventional solid-state battery 200′ is configured such that a single exterior material 13′ covers the entire circumference of the battery element 100′ in a cross-sectional view. To extract electricity from the battery element 100′ to the outside, a tab lead 22′, which is a component of a conductive portion, can be connected to the battery element 100′ by crossing the exterior material 13′. In other words, the tab lead 22′ is configured to cross the exterior material 13′ and protrude toward the outside. In this configuration, because the tab lead 22′ crosses the exterior material 13′, a small gap is generated between the tab lead 22′ and the exterior material 13′, and this gap may serve as a passageway for water vapor to pass from the outside to the battery element 100′.

[0136] In this regard, in a solid-state battery 200 according to one embodiment of the present invention, as shown in Figures 5 and 6, the conductive portion 20 connected to the battery element 100 is drawn out from the overlapping region 50. Therefore, compared to a conventional solid-state battery 200' that is covered with a single exterior material 13' (i.e., no overlapping region), the path length from the outside of the battery to the battery element 100 can be made longer by the length of the overlapping region 50 in the extending direction (longitudinal direction) of the overlapping region 50 in a cross-sectional view. As a result, water vapor 40 can be effectively prevented from reaching the battery element 100 from the outside, compared to the conventional solid-state battery 200'.

[0137] As can be seen from the above description, the overlap region 50 is a region where one exterior material and the other exterior material overlap each other. That is, the overlap region 50 is a region composed of two or more layers of exterior material. Therefore, the thickness of the overlap region 50 is thicker than the thickness of the exterior composite 10 in other portions other than the overlap region 50. As a result, the thickness of the exterior material in the overlap region 50 can be made thicker in the thickness direction (short direction) of the overlap region 50 in a cross-sectional view than in a conventional solid state battery 200′ that is covered by a single exterior material 13′ (i.e., no overlap region). Therefore, compared to the conventional solid state battery 200′, it is possible to effectively prevent water vapor 40 from reaching the battery element 100 from the outside.

[0138] If these exterior materials are permeable to water vapor (moisture and gas (carbon dioxide), etc.), the water vapor may penetrate into the battery element, and the positive electrode layer, negative electrode layer, and solid electrolyte layer may adsorb and absorb the water vapor, which may result in a decrease in battery performance. In consideration of this point, the water vapor permeability in the thickness direction of the exterior material is set to, for example, 5.0 × 10 -3 g / (m 2 ·day), preferably 0 to 5.0 × 10 -3 g / (m 2 The "water vapor transmission rate" referred to here refers to the transmission rate obtained using a gas transmission rate measuring device, Model WG-15S, manufactured by MORESCO, under measurement conditions of 85°C, 85% RH, and the MA method.

[0139] Alternatively, a gas permeability measurement device, Model GTms-1, manufactured by Advance Riko Co., Ltd., was used, and the water vapor permeability value obtained under the measurement conditions of 40°C, 90% RH, and a differential pressure of 1 atm was 1.0 x 10 -3 g / (m 2 It may be less than 1 day.

[0140] As shown in FIG. 5 , the armor composite 10 has an overlap region 50 formed by the first armor material 11 and the second armor material 12 overlapping each other. In one embodiment of the present invention, the overlap region 50 may be achieved by providing the second armor material 12 so as to cover the first armor material 11, as shown in FIG. 5 . In this case, with respect to the position of the battery element 100, the first armor material 11 in the overlap region 50 is located relatively inward, and the second armor material 12 in the overlap region 50 is located relatively outward. In this positioning of the first armor material 11 and the second armor material 12, the first thermoplastic resin layer 11a or the second thermoplastic resin layer 11c of the first armor material 11 faces the first thermoplastic resin layer 12a or the second thermoplastic resin layer 12c of the second armor material 12.

[0141] Note that "facing" here means that the layers face each other, and for example, as shown in Figure 7, means that the second thermoplastic resin layer 11c of the first exterior material 11 faces the second thermoplastic resin layer 12c of the second exterior material 12.

[0142] In the present invention, the opposing patterns in which the first thermoplastic resin layer 11a or the second thermoplastic resin layer 11c of the first exterior material 11 faces the first thermoplastic resin layer 12a or the second thermoplastic resin layer 12c of the second exterior material 12 in the overlap region 50 include the following patterns. (Facing mode 1) The first thermoplastic resin layer 11a of the first exterior material 11 and the first thermoplastic resin layer 12a of the second exterior material 12 face each other. (Facing configuration 2) The second thermoplastic resin layer 11c of the first exterior material 11 and the second thermoplastic resin layer 12c of the second exterior material 12 face each other. (Facing mode 3) The first thermoplastic resin layer 11a of the first exterior material 11 and the second thermoplastic resin layer 12c of the second exterior material 12 face each other. (Face-to-face configuration 4) The second thermoplastic resin layer 11c of the first exterior material 11 and the first thermoplastic resin layer 12a of the second exterior material 12 face each other. Of the above-mentioned facing modes 1 to 4, the solid state battery of the present invention may be facing mode 1 or facing mode 2 from the viewpoint of facilitating temperature control during heat fusion and / or facilitating heat fusion between thermoplastic resins.

[0143] Of the first and second thermoplastic resin layers of the first and second exterior materials 11 and 12, the thermoplastic resin layers with relatively low melting points preferably face each other in the overlap region 50. For example, the thermoplastic resin layers with relatively low melting points preferably contact each other in the overlap region 50. By adopting such a configuration, when the overlap region 50 is heated using an external heat source, only the facing thermoplastic resin layers with relatively low melting points can be softened and thermally bonded to each other, while the non-facing (i.e., outermost) thermoplastic resin layers with relatively high melting points do not soften and can maintain their shape. As a result, the shape of the entire solid-state battery 200 can be maintained while the facing portions of the first and second exterior materials 11 and 12 in the overlap region 50 are thermally bonded. In the first exterior material 11, the difference in melting point between the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c may be 20°C or more. In the second packaging material 12, the difference between the melting point of the first thermoplastic resin layer 12a and the melting point of the second thermoplastic resin layer 12c is preferably 20°C or more. By adopting such an embodiment, it becomes easier to thermally seal one of the resin layers together. Furthermore, in the above embodiment, in the first packaging material 11, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a. In the second packaging material 12, the melting point of the second thermoplastic resin layer 11c may be lower than the melting point of the first thermoplastic resin layer 11a.

[0144] The melting point of the thermoplastic resin layer having a relatively low melting point is preferably lower than the melting point of the thermoplastic resin layer having a relatively high melting point by at least 20° C. By adopting such a configuration, it becomes easier to heat-seal only the opposing thermoplastic resin layers having a relatively low melting point.

[0145] From the viewpoint of facilitating thermal fusion bonding, the melting point of the relatively low-melting thermoplastic resin layer may be lower than the melting point of the relatively high-melting thermoplastic resin layer by preferably 40°C or more, more preferably 60°C or more. On the other hand, from the viewpoint of facilitating temperature control during thermal lamination in the production of an exterior material, the melting point of the relatively low-melting thermoplastic resin layer may be lower than the melting point of the relatively high-melting thermoplastic resin layer by 120°C or less, preferably 100°C or less, more preferably 90°C or less. The "relatively low-melting thermoplastic resin layer" may be the "second thermoplastic resin layer," and the "relatively high-melting thermoplastic resin layer" may be the "first thermoplastic resin layer."

[0146] Because the thermoplastic resin of the exterior material according to one embodiment of the present invention is adhesive, it is not necessary to provide a sealant in the conductive portion 20 located in the overlap region 50. That is, the first thermoplastic resin layer 11a of the first exterior material 11 may be directly bonded to one main surface of the conductive portion 20, and the first thermoplastic resin layer 12a of the second exterior material 12 may be directly bonded to the other main surface of the conductive portion 20. That is, a sealant-less configuration may be adopted. Alternatively, the second thermoplastic resin layer 11c of the first exterior material 11 may be directly bonded to one main surface of the conductive portion 20, and the second thermoplastic resin layer 12c of the second exterior material 12 may be directly bonded to the other main surface of the conductive portion 20. Adopting such a configuration can prevent water vapor from penetrating into the solid-state battery 200 via the sealant. Furthermore, because a sealant is not used, the thickness of the exterior composite 10 in the overlap region 50 can be reduced, contributing to a reduction in the size of the solid-state battery 200.

[0147] When a sealant is provided in the conductive portion 20 located in the overlapping region 50, a sealant 24 may be provided in the conductive portion 20 located in the overlapping region 50 as shown in FIG.

[0148] The presence of the sealant 24 allows the conductive portion 20 located in the overlap region 50 to be bonded to the two exterior materials 11, 12 that constitute the overlap region 50. This allows the conductive portion 20 and the two exterior materials 11, 12 to be surface-bonded to each other in a cross-sectional view in the overlap region 50, making it easier to maintain the shape of the solid-state battery 200.

[0149] There are no particular limitations on the sealant 24, as long as the adhesive strength of the sealant does not change before and after the reflow process. For example, the sealant 24 may contain a resin with a melting point higher than the peak temperature during lead-free solder reflow.

[0150] The solid state battery according to one embodiment of the present invention may further have the following features.

[0151] In one embodiment, the conductive portion 20 may be provided so as to be sandwiched between the first exterior packaging material 11 and the second exterior packaging material 12 that constitute the exterior packaging composite 10 (see Figs. 5 to 8, etc.). Specifically, the first exterior packaging material 11 is in contact with the conductive portion 20, and the second exterior packaging material 12 is in contact with the conductive portion 20, and in this state the conductive portion 20 is sandwiched between the first exterior packaging material 11 and the second exterior packaging material 12. In another embodiment, as shown in Fig. 5, the conductive portion 20 may be provided between the outer surface of the first exterior packaging material 11 and the inner surface of the second exterior packaging material 12. In this embodiment, the conductive portion 20 is arranged between the first exterior packaging material 11 and the second exterior packaging material 12 so as to be approximately parallel to the first exterior packaging material 11 and the second exterior packaging material 12. 12 It is sandwiched between.

[0152] That is, the conductive portion 20 may be positioned between the first exterior material 11 and the second exterior material 12, and the conductive portion 20, the first exterior material 11, and the second exterior material 12 may be integrated together. By adopting such a configuration, exterior materials are positioned on both sides of the conductive portion 20 in a cross-sectional view, so that the conductive portion 20 can be in surface contact with each of the two exterior materials, and minute gaps between the conductive portion 20 and each exterior material can be suitably reduced. This makes it possible to suitably prevent water vapor from passing through the overlap region 50.

[0153] From the viewpoint of preventing water vapor from passing through the overlapping region 50 on both the positive electrode side and the negative electrode side, two overlapping regions 50 may be provided in a cross-sectional view. Specifically, one may be provided to sandwich the conductive portion (corresponding to tab lead 22) on the positive electrode side, and the other may be provided to sandwich the conductive portion (corresponding to tab lead 22) on the negative electrode side.

[0154] In one embodiment, the end surface electrodes of the conductive portion 20 and the armor composite 10 are preferably provided along the contour surface of the battery element 100 (see FIGS. 5 to 12, etc.).

[0155] In this specification, the "contour surface of the battery element 100" refers to the surface that forms the shape or appearance of the battery element 100. In this specification, the phrase "the end surface electrodes of the conductive portion 20 and the exterior composite 10 are provided along the contour surface of the battery element 100" refers to a state in which the end surface electrodes of the conductive portion 20 and the exterior composite 10 are provided approximately parallel to the extension direction of the contour surface of the battery element 100.

[0156] That is, it is preferable that the end surface electrodes of the conductive portion 20 and the exterior composite 10 extend in approximately the same direction as the extension direction of the contoured surface of the battery element 100. In this specification, the "extension direction of the contoured surface of the battery element 100" means the direction in which the contoured surface extends in the longitudinal direction. It is sufficient that the conductive portion 20 and the exterior composite 10 extend in approximately the same direction as the extension direction of the contoured surface of the battery element 100 at least at a glance, and it is not necessary that the end surface electrodes of the conductive portion 20 and the exterior composite 10 extend in exactly the same direction as the extension direction of the contoured surface of the battery element 100. For example, due to the relative positions of the conductive portion 20, the exterior composite 10, and the battery element 100, there may be portions where a portion of the conductive portion 20 and a portion of the exterior composite 10 do not extend approximately coaxially with the extension direction of the contoured surface of the battery element 100.

[0157] As described above, in the conventional solid-state battery 200', the tab lead 22', which is a component of the conductive portion, is configured to traverse the exterior packaging material 13' and protrude toward the outside. Therefore, the area required for mounting the conventional solid-state battery 200' is increased by the area of ​​the tab lead protruding toward the outside. Furthermore, since this tab lead is a part that extracts electricity from the solid-state battery and does not contribute to power generation by the solid-state battery, the area of ​​the protruding conductive portion may lead to a decrease in the power generation capacity per unit area of ​​the solid-state battery.

[0158] In this regard, in one embodiment of the present invention, the conductive portion 20 is drawn out from an overlapping region 50 where the first exterior material 11 and the second exterior material 12 overlap each other. The overlapping region 50 is a component of the exterior composite 10 that covers the battery element 100, and therefore can generally have a shape that follows the contour of the battery element 100. Therefore, the conductive portion 20 drawn out from the overlapping region 50 can also have a structure that follows the contour of the battery element 100 and suppresses protrusion. Because the conductive portion 20 (specifically, the tab lead 22) can have a structure that follows the contour of the battery element 100 rather than a protruding structure, the solid-state battery 200 according to one embodiment of the present invention can be surface-mounted on an electronic substrate as a whole.

[0159] In one embodiment, the portion of the conductive portion 20 drawn out to the outside (corresponding to the tab lead 22) preferably has a bent portion 20A (see, for example, FIGS. 6 to 8). The bent portion here refers to a bent portion. There are no particular limitations on the shape of the bend. For example, as shown in FIGS. 6 to 8, the portion of the conductive portion 20 drawn out to the outside may be bent so as to have a right-angled portion. Alternatively, the portion of the conductive portion 20 drawn out to the outside may be bent so as to have an arc (curved) portion, specifically, so as to be bent so as to follow the surface of the exterior material. There are no particular limitations on the shape of the tab lead 22 connected to the end electrode 21 drawn out to the outside. For example, as shown in FIG. 7, the tab lead 22 may be drawn out so as to have a U-shaped cross section. In other words, the tab lead 22 may have a shape including multiple bent portions.

[0160] 6, the portion of the conductive part 20 that is drawn out (corresponding to the tab lead 22) is connected to the electronic substrate 300 or the like when the solid-state battery 200 according to one embodiment of the present invention is surface-mounted. In this case, the portion of the conductive part 20 that is drawn out (corresponding to the tab lead 22) can be bent depending on the mounting area of ​​the solid-state battery 200 according to one embodiment of the present invention, the positional relationship between the solid-state battery 200 and the electronic substrate 300, or the like, or the method of connecting the solid-state battery 200 and the electronic substrate 300, or the like.

[0161] The length of the conductive portion 20 drawn out to the outside is not particularly limited as long as electricity can be extracted from the conductive portion 20. From the viewpoint of suitable surface mounting of the solid-state battery, it is preferable that the end of the drawn-out conductive portion 20 be provided on at least one of the upper and lower surfaces of the battery element 100 covered with the first exterior material 11 or the second exterior material 12. Specifically, it is preferable that the end of the conductive portion 20 (specifically, the tab lead 22) that follows the contour of the battery element 100 be provided on the upper or lower surface of the solid-state battery 200, for example, on the lower surface. This allows the solid-state batteries 200 to be mounted in the same row on the electronic substrate 300, thereby reducing the overall surface mounting area. Furthermore, from the viewpoint of reducing the overall surface mounting area and more reliably achieving surface mounting of the solid-state battery 200, it is preferable that at least a portion of the drawn-out portion of the conductive portion 20 be in "surface" contact with the surface of the electronic substrate 300. The contact at the "surface" can increase the contact area between the conductive part 20 and the electronic substrate 300. This configuration can be achieved by providing a bent portion at the drawn-out portion of the conductive part 20 so that at least a part of the drawn-out portion of the conductive part 20 is approximately parallel to the surface of the electronic substrate 300, as shown in FIG.

[0162] The drawn-out end of conductive portion 20 does not necessarily have to be fixed to first exterior material 11 or second exterior material 12, and may be a free end that is freely movable. In this regard, from the viewpoint of reducing the mounting area, in one embodiment, a configuration in which at least the drawn-out end of conductive portion 20 is fixed to first exterior material 11 or second exterior material 12 is preferred.

[0163] By adopting such a configuration, the drawn-out end of the conductive part 20 can be brought into close contact with the side surface of the battery element 100 and can maintain this close contact state. This can more reliably prevent the part protruding from the solid-state battery, thereby reducing the mounting area.

[0164] Furthermore, by maintaining the above-described tight contact state, it is possible to suitably prevent the end of the drawn-out conductive portion 20 from being bent or deformed when an external force is applied to the end of the drawn-out conductive portion 20. As a result, the solid-state battery 200 can be suitably surface-mounted on the electronic substrate 300.

[0165] The method for fixing the end of the drawn-out conductive portion 20 to the first exterior material 11 or the second exterior material 12 is not particularly limited. For example, the end of the drawn-out conductive portion 20 may be fixed to the first exterior material 11 or the second exterior material 12 by thermal fusion. For example, the end of the drawn-out conductive portion 20 may be fixed to the first exterior material 11 or the second exterior material 12 using an adhesive. The adhesive may be in the form of, for example, a liquid, paste, sheet, solid, or powder. The type of adhesive may be, for example, a water-based adhesive, a chemical reaction adhesive, a solvent-based adhesive, or a hot-melt adhesive. The adhesive is not particularly limited as long as its adhesive strength does not change before and after the reflow process. For example, the adhesive material may be at least one selected from the group consisting of silicone-based resins, acrylic-based resins, epoxy-based resins, and urethane-based resins.

[0166] 7, tab lead 22 is connected to end surface electrode 21, and electricity can be extracted from battery element 100 to the outside via tab lead 22. The method for connecting tab lead 22 and end surface electrode 21 is not particularly limited as long as tab lead 22 and end surface electrode 21 are electrically connected. For example, tab lead 22 and end surface electrode 21 may be connected by a conductive paste or by welding.

[0167] During charging and discharging of the solid-state battery 200, ions move through the solid electrolyte layer between the positive electrode layer and the negative electrode layer, causing the active material contained in each electrode layer to expand and contract along the stacking direction. In particular, expansion of the active material, i.e., the electrode layers, along the stacking direction generates tensile stress acting upward and tensile stress acting downward. In this regard, according to this embodiment, when the solid-state battery 200 is surface-mounted on the electronic substrate 300, a small space can be formed between the solid-state battery 200 and the electronic substrate 300. The presence of such a space can accommodate the expanding portion of the solid-state battery 200 due to the expansion of the electrode layers along the stacking direction (see FIG. 9 ).

[0168] In one embodiment, the overlap region 50 may be provided along the side surface of the battery element 100. It may be provided along the entire side surface of the battery element 100 (see, for example, FIGS. 6 to 9). In this specification, the term "side surface" refers to a surface that extends relatively perpendicular to the upper or lower surface of each surface constituting the battery element 100. As can be seen from the above explanation, there may be multiple "side surfaces" depending on the configuration of the battery element 100. Therefore, in the present invention, "an overlap region is provided along the side surface of the battery element 100" means that the overlap region is provided with respect to a surface of the battery other than the upper or lower surface of the battery element 100.

[0169] By adopting such a configuration, the overlapping region 50 does not protrude from the battery element 100, thereby reducing the mounting area required for surface mounting. In particular, when the end of the conductive portion 20 (specifically, the tab lead 22) along the outline of the battery element 100 is provided on the upper or lower surface side of the solid-state battery 200, for example, on the lower surface side, the portion of the conductive portion 20 (specifically, the tab lead 22) other than the end can be accommodated within the overlapping region 50 along the side surface of the battery element 100, thereby making it possible to preferably both surface mount the solid-state battery 200 on the electronic substrate 300 and prevent water vapor from entering the battery.

[0170] From the viewpoint of preventing water vapor from penetrating into the battery element 100, the overlapping region 50 may be wide. Specifically, the longer the length of the overlapping region 50 along the longitudinal direction of the tab lead 22 in a cross-sectional view, the better. The length of the overlapping region 50 may be 10% or more, preferably 20% or more, 30% or more, and more preferably 40% or more, of the height of the battery element 100 (i.e., the length from the top surface to the bottom surface of the battery element 100). Furthermore, from the viewpoint of facilitating adjustment of the position and length of the conductive portion 20 extended to the outside, the length of the overlapping region 50 may be 150% or less, preferably 100% or less, more preferably 80% or less, even more preferably 70% or less, and particularly preferably 60% or less, of the height of the battery element 100. The length of the overlapping region 50 does not have to be uniform throughout the overlapping region 50. For example, as shown in the cross-sectional view of FIG. 12, the length of the overlapping region 50 may vary.

[0171] In one embodiment, the first exterior material 11 and the second exterior material 12 have metal layers 11b and 12b as intermediate layers (see FIG. 7). When the battery element 100 is covered with the first exterior material 11, the metal layer 11b, which is the intermediate layer of the exterior material, is electrically connected to the positive end surface electrode 21 and the negative end surface electrode 21, and an insulating material may be provided on the end surfaces of the exterior material to prevent a short circuit via the metal layer 11b. The method of insulating the battery element 100 to provide the insulating material is not particularly limited, and any method may be used as long as it contributes to preventing a short circuit of the battery element 100 via the exterior material.

[0172] The relative positions of the conductive portions 20 and the overlapping regions 50 are not particularly limited, and any structure may be adopted depending on the surface mounting configuration. For example, structures such as those shown in FIGS. 11 and 12 can be adopted. As an example, in the structure shown in FIG. 11 , the exposed portions of the conductive portions 20 on the positive and negative sides are positioned so as to face each other across the battery element 100. This positions the conductive portions 20 on the positive and negative sides of the solid-state battery 200 at a greater distance from each other, thereby reducing the risk of short-circuiting between the two electrodes. Furthermore, as shown in FIG. 12 , the overlapping regions on the positive and negative sides and the tab lead 22 can be designed asymmetrically depending on the mounting surface of the solid-state battery 200. This allows for flexible surface mounting depending on the surface configuration of the mounting surface of the solid-state battery 200.

[0173] Moreover, the thickness of the overlapping region 50 is determined by the thicknesses of the first sheath material 11 and the second sheath material 12 that form the overlapping region.

[0174] The thickness of the overlap region is preferably 2 μm or more and 1000 μm or less, more preferably 4 μm or more and 600 μm or less, and even more preferably 6 μm or more and 200 μm or less, for example 100 μm, in order to further suppress deterioration of battery performance due to the penetration of water vapor into the battery element.

[0175] The above has been a detailed description of the application of the packaging material of the present invention to a solid-state battery using the packaging material of the present invention as an example. The various aspects of the solid-state battery described above can also be applied to other electronic devices, as shown in the following embodiments.

[0176] <Third embodiment> For example, an exterior packaging material according to one embodiment of the present invention can be applied to a circuit board (or composite module, etc.) 610 including a plurality of electronic devices (e.g., capacitors, resistors, coils, diodes, or transistors, etc.), as shown in Fig. 13. Fig. 13 shows a packaged circuit board 600, which is constructed by covering the circuit board 610 with an exterior packaging composite 10 consisting of a first exterior packaging material 11 and a second exterior packaging material 12.

[0177] (Method of manufacturing the solid battery of the present invention) A method for manufacturing a solid-state battery according to one embodiment of the present invention will be described below. Hereinafter, a method for manufacturing a solid-state battery according to a first embodiment and a method for manufacturing a solid-state battery according to a second embodiment will be described as solid-state batteries equipped with an exterior material of the present invention. These manufacturing methods are merely examples of methods for manufacturing a solid-state battery equipped with an exterior material of the present invention, and do not limit the present invention.

[0178] First, before explaining the manufacturing method of the first embodiment, the manufacturing method of the second embodiment will be explained.

[0179] Manufacture of a solid-state battery according to one embodiment of the present invention method (Second embodiment) roughly includes the following steps (i) to (iv) in order (see Fig. 14(a) to Fig. 14(h)). Specifically, the method for producing a solid-state battery according to one embodiment of the present invention includes: (i) preparing a battery element 100 including a positive electrode layer 110, a negative electrode layer 120, and a solid electrolyte layer 130 interposed between the positive electrode layer 110 and the negative electrode layer 120; (ii) providing a first exterior material 11 so as to cover a portion of the battery element 100; (iii) providing a conductive portion 20 that can extract electricity from the battery element 100 to the outside; (iv) providing a second exterior material 12 so as to cover the remaining part of the battery element 100 other than the part. In particular, the manufacturing method for a solid-state battery according to one embodiment of the present invention is characterized in that an overlapping region 50 is formed where the first exterior material 11 and the second exterior material 12 overlap each other, and the second exterior material 12 is provided so that the conductive portion 20 is drawn out from the overlapping region 50 to the outside. Furthermore, the first exterior material 11 and the second exterior material 12 each include a metal layer, a first thermoplastic resin layer located on the first main surface side of the metal layer, and a second thermoplastic resin layer located on the second main surface side of the metal layer, and are characterized in that the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C.

[0180] In the following, one production method will be described as an example for better understanding of the present invention, but the present invention is not limited to this method. Furthermore, the chronological order of the following description is merely for the convenience of explanation and is not necessarily binding.

[0181] [Preparing the first exterior material] First, as shown in Fig. 14(a), a first packaging material 11 of the present invention is prepared. The first packaging material 11 includes a metal layer 11b, a first thermoplastic resin layer 11a located on a first main surface side of the metal layer 11b, and a second thermoplastic resin layer 11c located on a second main surface side of the metal layer 11b. The first packaging material 11 may be prepared by fabricating it according to the above-described (method for manufacturing a packaging material of the present invention).

[0182] [Deep drawing of the first exterior material] Next, as shown in FIG. 14(b), the first exterior material 11 is drawn to form it into a shape that covers the battery element 100. The drawing is not particularly limited as long as it is a processing method in which pressure is applied to the first exterior material 11 to squeeze it into a concave (or cup) shape, and the first exterior material 11 is shaped to cover the battery element 100. For example, the first exterior material 11 is placed on a box-shaped mold that conforms to the shape of the battery element 100, and pressure is applied from above the first exterior material 11 using a mold that mimics the shape of the battery element 100, thereby forming the first exterior material 11 that covers the battery element 100. However, the method is not limited to this, and the drawing may be performed by pressing the battery element 100 against the first exterior material 11.

[0183] [Installation of first exterior material 11] Next, as shown in FIG. 14(c), the battery element 100 is inserted into the first exterior material 11 obtained by the above method, and the first exterior material 11 is attached to the battery element 100. Specifically, the first exterior material covers the battery element 100 so that the top or bottom surface is partially exposed. In a preferred embodiment, the first exterior material is attached so that it covers the surfaces of the battery element 100 other than the top or bottom surface. More specifically, the first exterior material 11 is attached so that the end surface of the first exterior material is positioned at the boundary line between the top surface and side surface of the battery element 100. Note that end surface electrodes 21 may be attached in advance to the side surfaces of the battery element 100.

[0184] An insulating material 31 may be provided on an end surface of the first exterior material 11 to prevent short-circuiting of the battery element 100. There are no particular limitations on the insulating material 31 as long as it has electrical insulation properties, and it may be, for example, an insulating resin. Examples of the insulating resin material include at least one selected from the group consisting of epoxy resins, acrylic resins, phenolic resins, and synthetic rubbers.

[0185] [Installation of tab lead 22] Next, as shown in FIGS. 14(d) and 14(e), a tab lead 22 is attached to an end electrode 21 provided on a battery element 100 that is not covered with the first exterior material 11. Preferably, a conductive adhesive 23 is applied to the end of the tab lead 22 by metal mask printing, thereby electrically connecting the end of the tab lead 22 and the end electrode 21 of the battery element 100 to each other. The conductive adhesive 23 may be a conductive paste, for example, made of a resin material containing a conductive filler. Examples of the conductive filler include at least one selected from the group consisting of nickel, copper, aluminum, gold, and carbon. Examples of the resin material include at least one selected from the group consisting of epoxy resins, acrylic resins, silicone resins, and urethane resins.

[0186] 14(f), the tab lead 22 is positioned so that it follows the contour of the side surface of the battery element 100, starting from the end of the tab lead 22 connected to the end surface electrode 21 of the battery element 100. When the tab lead 22 is positioned to follow the side of the battery element 100 across the side, the tab lead 22 may be bent.

[0187] [Installation of second exterior material 12] Next, a second exterior material 12 is prepared. The second exterior material 12 includes a metal layer 12b, a first thermoplastic resin layer 12a located on the first main surface side of the metal layer 12b, and a second thermoplastic resin layer 12c located on the second main surface side of the metal layer 12b. The second exterior material 12 may be prepared by fabricating it according to the above-described method for manufacturing an exterior material of the present invention. As shown in FIG. 14(g), the tab leads 22 are positioned so as to fit along the contoured surface of the side surface of the battery element 100, and then the second exterior material 12 is placed on the surface of the battery element 100 that is not covered by the first exterior material 11. Thereafter, the end of the second exterior material 12 is placed so as to fit along the side surface of the battery element 100. At this time, because the end of the first exterior material 11 is already positioned on the side surface of the battery element 100, an overlapping region 50 is formed where the second exterior material 12 and the first exterior material 11 overlap. Specifically, a layer is formed in which the battery element 100, first external packaging material 11, tab lead 22, and second external packaging material 12 are arranged in this order from the battery element 100 toward the outside, and the tab lead 22 is drawn out from the overlapping region 50. In other words, the conductive part 20 consisting of the end surface electrode 21 and the tab lead 22 is drawn out from the overlapping region to the outside.

[0188] It is preferable that first exterior material 11 and second exterior material 12 are arranged in battery element 100 so that the first thermoplastic resin layer of first exterior material 11 and the first thermoplastic resin layer of second exterior material 12 face each other in overlapping region 50. It is also preferable that the opposing thermoplastic resins in overlapping region 50 have relatively low melting points.

[0189] From the viewpoint of preventing water vapor from penetrating into the battery element 100, the first exterior material 11 located in the overlapping region 50, the tab lead 22 as a component of the conductive portion 20, and the second exterior material 12 may be brought into close contact with each other. The method for bringing them into close contact is not particularly limited, but they can be brought into close contact by heat fusion, mechanical bonding, crimping, welding, adhesive, or the like. In the case of heat fusion, for example, in the case of FIG. 14(g) or FIG. 14(h), the overlapping region 50 may be heated using an external heat source, and the first exterior material 11 and the second exterior material 12 may be heat fused to the tab lead 22. Alternatively, in the case of FIG. 14(e) or (f), the tab lead 22 may be heated, and the first exterior material 11 and the second exterior material 12 may be attached to the heated tab lead 22 and heat fused. In another embodiment, the intimate contact between the first exterior material 11, the tab lead 22, and the second exterior material 12 may be of To further improve adhesion, a sealant 24 may be applied to the tab lead 22 in advance, and the sealant 24 may be provided in the overlap region 50. For example, the sealant 24 is not particularly limited as long as the adhesive strength of the sealant 24 does not change before and after the reflow process. For example, the sealant 24 may contain a resin having a melting point higher than the peak temperature during reflow. Note that the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c constituting the packaging material of the present invention each have improved adhesiveness, and therefore can be bonded to the tab lead 22 without using the sealant 24. Furthermore, even when a sealant 24 is used, a thinner sealant than conventional sealants can be used.

[0190] [Fixing tab lead 22] Finally, as shown in FIG. 14(h), one free end of the tab lead 22, i.e., the end of the tab lead 22 that is not connected to the battery element 100 (i.e., the end of the drawn-out conductive portion 20), is positioned so as to fit along the contour surface of the battery element 100. Specifically, the tab lead 22 is bent so as to come into contact with the first external packaging material 11. At this time, the contact point between the tab lead 22 and the first external packaging material 11 may be heated to thermally seal the tab lead 22 to the first external packaging material 11. Alternatively, an adhesive or the like may be applied to the contact point between the tab lead 22 and the first external packaging material 11 to bond and fix the tab lead 22 to the first external packaging material 11. There are no particular limitations on the adhesive as long as the adhesive strength of the sealant 24 does not change before and after the reflow process.

[0191] Through these steps, a solid state battery 200 according to one embodiment of the present invention can finally be obtained ( FIG. 14( h) ). Note that the bending of the tab lead 22 and adhesive fixation to the first exterior material in the above-described “Fixing the tab lead 22” step may be performed, for example, immediately before the solid state battery 200 of the present invention is surface-mounted on an electronic substrate 300. Specifically, after manufacturing to the state shown in FIG. 14( g), manufacturing may be stopped temporarily before fixing the tab lead 22, and the battery may be temporarily stored in the state shown in FIG. 14( g) . Depending on the shape of the electronic substrate to be subsequently surface-mounted, design factors such as whether or not to bend the tab lead 22, the length of the drawn-out portion of the tab lead 22, the adhesive fixation position of the tab lead 22, the bending location, and the bending direction may be appropriately determined. By employing these steps, the solid state battery 200 of the present invention can be flexibly surface-mounted according to the shape of the electronic substrate.

[0192] The finally obtained solid state battery 200 according to one embodiment of the present invention can achieve the following effects.

[0193] Specifically, in the obtained solid-state battery 200 according to one embodiment of the present invention, the conductive portion 20 connected to the battery element 100 is drawn out from the overlap region 50. Therefore, compared to a conventional solid-state battery 200′ that is covered with a single exterior material 13′ (i.e., no overlap region), the path length from the outside of the battery to the battery element 100 can be increased by the length of the overlap region 50 in the extension direction (longitudinal direction) of the overlap region 50 in a cross-sectional view. As a result, water vapor 40 can be effectively prevented from reaching the battery element 100 from the outside, compared to the conventional solid-state battery 200′.

[0194] As can be seen from the above description, the overlap region 50 is a region where one exterior material and the other exterior material overlap each other. That is, the overlap region 50 is a region composed of two or more layers of exterior material. Therefore, the thickness of the overlap region 50 is thicker than the thickness of the exterior composite 10 in other portions other than the overlap region 50. As a result, the thickness of the exterior material in the overlap region 50 can be made thicker in the thickness direction (short direction) of the overlap region 50 in a cross-sectional view than in a conventional solid state battery 200′ that is covered by a single exterior material 13′ (i.e., no overlap region). Therefore, compared to the conventional solid state battery 200′, it is possible to effectively prevent water vapor 40 from reaching the battery element 100 from the outside.

[0195] Furthermore, the method for producing a solid-state battery according to one embodiment of the present invention (first embodiment) roughly comprises the following steps (i) to (iv) in order (see Fig. 14(a) to Fig. 14(h)). Specifically, the method for producing a solid-state battery according to one embodiment of the present invention comprises: (i) preparing a battery element 100 including a positive electrode layer 110, a negative electrode layer 120, and a solid electrolyte layer 130 interposed between the positive electrode layer 110 and the negative electrode layer 120; (ii) providing an end electrode 21 that can extract electricity from the battery element 100 to the outside; (iii) providing a packaging material 11 so as to cover a part of the battery element 100. The exterior material 11 includes a metal layer 11b, a first thermoplastic resin layer 11a located on the first main surface side of the metal layer 11b, and a second thermoplastic resin layer 11c located on the second main surface side of the metal layer 11b, and is characterized in that the melting points of the first thermoplastic resin layer 11a and the second thermoplastic resin layer 11c are both higher than 260°C.

[0196] First, the exterior material 11 is prepared as described in the above <Second embodiment> [Preparation of first exterior material] (see FIG. 14 ( a ) Next, the exterior material 11 is processed into a concave (or cup) shape as described in the above <Second embodiment> [Deep drawing of exterior material 11] (FIG. 14 ( b )Next, the battery element 100 having the end surface electrodes 21 is inserted into the first exterior material 11 that has been processed into a concave shape, and the exterior material 11 is attached to the battery element 100 (see FIG. 14 ( c ) ).

[0197] Tab leads 22 are attached to the end surface electrodes 21. Next, the exterior material 11 is attached to the battery element 100 to which the concave exterior material 11 is attached so as to cover the battery element 100 (to the remaining portion of the battery element 100 that is not covered by the concave exterior material 11). At this time, the exterior material 11 is attached so that the tab leads 22 attached to the end surface electrodes 21 are exposed to the outside. By going through the above steps, the solid state battery of the first embodiment is obtained.

[0198] Although one embodiment of the present invention has been described above, it is merely a typical example within the scope of application of the present invention. Therefore, it will be readily understood by those skilled in the art that the present invention is not limited to this embodiment and that various modifications can be made. [Example]

[0199] Table 1 shows the configurations of the exterior packaging materials of Examples 1 to 5 and Comparative Example 1, and the evaluation results of the solid state batteries equipped with these exterior packaging materials.

[0200] Example 1 (Preparation of the first exterior material) The first exterior material was prepared as follows. First, a film with a melting point of 10 ... 3 05 °C A highly heat-resistant polyamide is Degree 2 90 °C The aluminum foil and the highly heat-resistant polyamide were then heat-sealed to form an integrated product. 2 69 °C A certain polyethylene naphthalate is heated Degree 2 55 °C The first exterior packaging material was produced by heat sealing.

[0201] (Preparation of second exterior material) The second packaging material was produced in the same manner as the first packaging material.

[0202] (Preparing the battery element) A battery element including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer was prepared, and end electrodes capable of extracting electricity from the battery element to the outside were provided.

[0203] (Exterior material molding) The first and second exterior materials were drawn to form them into a cup shape. During the forming, the outer side of the cup-shaped first exterior material was formed as a thermoplastic resin layer with a relatively low melting point, and the inner side of the cup-shaped second exterior material was formed as a thermoplastic resin layer with a relatively low melting point. This ensured that the thermoplastic resin layers with relatively low melting points faced each other in the overlapping region to be formed later.

[0204] Battery with end electrodes element A cup-shaped first exterior material was attached to the battery element. Next, a tab lead was attached to the end electrode exposed to the outside on the side not covered by the first exterior material 11. The tab lead attached to the end electrode was positioned so as to follow the contour of the side surface of the battery element. Next, a cup-shaped second exterior material was attached so as to cover the surface of the battery element not covered by the cup-shaped first exterior material. As a result, an overlapping region where the second exterior material and the first exterior material overlap was formed on the side surface of the battery element. The overlapping region was heated, and the first exterior material and the second exterior material in the overlapping region were heat-fused and sealed. In this way, a solid-state battery covered with an exterior material was obtained.

[0205] <Examples 2 to 5> Examples 2 to 5 were obtained in the same manner as in Example 1, except that the thermoplastic resin layers shown in Examples 2 to 5 in Table 1 were used.

[0206] <Comparative Example 1> Comparative Example 1 was obtained in the same manner as in Example 1, except that the thermoplastic resin layer shown in Comparative Example 1 in Table 1 was used.

[0207] <Surface mount evaluation> The solid-state battery covered with the exterior material was mounted on a circuit board (FR4) using solder paste. Surface mountability was evaluated based on JIS C60068-2-58. The evaluation results are shown in Table 1.

[0208] <Evaluation of battery element deterioration due to water vapor> The solid-state battery covered with the exterior material was mounted on a circuit board (FR4) using solder paste, and its characteristics were evaluated under high temperature and high humidity conditions of 60°C and 90% RH, as well as 60°C and 50% RH. The evaluation results are shown in Table 1.

[0209] [Table 1]

[0210] From the above results, it was confirmed that the solid state battery provided with the packaging material of the present invention can be surface mounted and that the battery element was not deteriorated by water vapor. [Industrial Applicability]

[0211] The packaging material according to one embodiment of the present invention can be used in various electronic devices that require water vapor barrier properties. By way of example only, the packaging material according to one embodiment of the present invention can be used in batteries (primary batteries, secondary batteries, and particularly solid-state batteries), circuit boards, composite modules, electronic components, and the like. The solid-state battery according to one embodiment of the present invention can be used in various fields where battery use or power storage is anticipated. Furthermore, the electronic device according to one embodiment of the present invention can be used in various fields where electrical control is required. Although merely illustrative, the solid-state battery according to one embodiment of the present invention can be used in the electrical, information, and communications fields in which mobile devices and the like are used (for example, mobile devices such as mobile phones, smartphones, smart watches, laptops and digital cameras, activity monitors, arm computers, and electronic paper), household and small industrial applications (for example, power tools, golf carts, and household, nursing care, and industrial robots), large industrial applications (for example, forklifts, elevators, and port cranes), transportation systems (for example, hybrid cars, electric cars, buses, trains, electrically assisted bicycles, and electric motorcycles), power system applications (for example, various power generation systems, road conditioners, smart grids, and general household installation-type power storage systems), medical applications (medical devices such as earphones and hearing aids), pharmaceutical applications (dose management systems), as well as the IoT field, and space and deep-sea applications (for example, space probes, submersible research vessels, and the like). [Explanation of symbols]

[0212] 10: Exterior complex 11, 11': exterior material, first exterior material 11a, 11a': first thermoplastic resin layer 11b,11b': Metal layer 11c, 11c': second thermoplastic resin layer 11d'(11e'):Adhesive layer 12: Second exterior material 12a: First thermoplastic resin layer 12b: Metal layer 12c: Second thermoplastic resin layer 13': Single cladding 20: Conductive part 20A: Bent part 21: End electrode 22, 22': Tab lead 23:Conductive adhesive 24: Sealant 31: Insulation material 40: Water vapor 50: Overlapping area 100,100': Battery element 110: Positive electrode layer 120: negative electrode layer 130: Solid electrolyte layer 200,200': Solid state battery 300:Electronic base materials 310: Electronic substrate connection part 401: First heating roll 402: Second heating roll 501: First cooling roll 502: Second cooling roll 511a: First thermoplastic resin material 511b: Metal layer 511c: Second thermoplastic resin material 600: Packaged circuit board 610: Circuit board

Claims

1. a battery element including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an exterior material covering the battery element; and a conductive part capable of extracting electricity from the battery element to the outside, the exterior packaging material includes a metal layer, a first thermoplastic resin layer located on a first main surface side of the metal layer, and a second thermoplastic resin layer located on a second main surface side of the metal layer and having a melting point lower than that of the first thermoplastic resin layer, the melting points of the first thermoplastic resin layer and the second thermoplastic resin layer are both higher than 260°C; the battery element is provided with an exterior composite made of two or more exterior materials, the two or more exterior materials including a first exterior material and a second exterior material, and the first exterior material and the second exterior material form an overlapping region where they overlap each other; With respect to the position of the battery element as a reference, the first exterior material is located relatively inside and the second exterior material is located relatively outside in the overlapping region, The second thermoplastic resin layer of the first exterior material and the second thermoplastic resin layer of the second exterior material face each other, the conductive portion is drawn out from the overlapping region to the outside.

2. The solid-state battery according to claim 1 , wherein the difference between the melting point of the first thermoplastic resin layer and the melting point of the second thermoplastic resin layer is 20° C. or more.

3. 2. The solid-state battery according to claim 1, wherein the second thermoplastic resin layer of the first exterior material is directly bonded to one main surface of the conductive portion, and the second thermoplastic resin layer of the second exterior material is directly bonded to the other main surface of the conductive portion.

4. 2. The solid-state battery according to claim 1, wherein the length of the overlapping region is at least 10% or more of the height of the battery element.

5. The solid-state battery according to claim 1 , wherein the overlapping region is provided along a side surface of the battery element.

6. 2. The solid-state battery according to claim 1, wherein at least an end portion of the drawn-out conductive portion is provided on at least one of an upper surface side and a lower surface side of the battery element covered with the first exterior material or the second exterior material.

7. The solid-state battery according to claim 1 , wherein the conductive portion and the armor composite extend in substantially the same direction as the extending direction of the contoured surface of the battery element.

8. The solid-state battery according to claim 1 , wherein the exterior material is provided along a contoured surface of the battery element.

9. The solid-state battery according to claim 1 , wherein the portion of the conductive portion that is drawn out to the outside includes a bent portion.

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