Outer materials for all-solid-state batteries and all-solid-state batteries

Abstract

Provided is an all-solid-state battery sheathing material that has good insulation properties even at high temperatures.　The present invention is directed to an all-solid-state battery sheathing material which is for enclosing a solid-state battery main body 5 and which comprises: a base material layer 11; a metal foil layer 12 that is laminated on the inner surface side of the base material layer 11; and a sealant layer 13 that is laminated on the inner surface side of the metal foil layer 12. A heat-resistant gas barrier layer 21 made of resin is provided between the metal foil layer 12 and the sealant layer 13, and an opening 15 is provided in a portion of the sealant layer 13 corresponding to the solid-state battery main body 5. In that opening 15, the heat-resistant gas barrier layer 21 is disposed so as to be exposed on the inner surface side.

Description

Technical Field

[0001] The present invention relates to an exterior material for an all-solid-state battery used as a high-power battery such as an in-vehicle battery, a battery for a portable device such as a mobile electronic device, a battery for storing regenerative energy, and an all-solid-state battery.

Background Art

[0002] Since a conventionally widely used lithium-ion secondary battery uses a liquid electrolyte as an electrolyte, there has been a risk of ignition due to short circuit in some cases where the separator is destroyed due to liquid leakage or the generation of dendrites.

[0003] On the other hand, an all-solid-state battery is a battery using a solid electrolyte, so there is no liquid leakage or dendrite generation, and the separator is not destroyed. Therefore, there is no concern about ignition due to the destruction of the separator, and it has been highly regarded from the viewpoint of safety and the like.

[0004] A normal all-solid-state battery is configured by enclosing a solid battery body such as an electrode active material and a solid electrolyte inside an exterior material as a casing. In this all-solid-state battery, as the research on the solid electrolyte progresses, the performance required for the exterior material is gradually emerging as a different part from the exterior material of a battery using a conventional liquid electrolyte, and various exterior materials have been proposed to satisfy the performance for an all-solid-state battery.

[0005] The exterior material for an all-solid-state battery basically includes a metal foil layer and a heat-sealing layer (sealing layer) laminated inside thereof, and encloses the solid battery body by heat-sealing the sealing layer.

[0006] For example, the casing material for all-solid-state batteries shown in Patent Document 1 has a protective film interposed between the metal foil layer and the sealant layer, and the sealant layer uses a material with high hydrogen sulfide gas permeability. Furthermore, the casing material for all-solid-state batteries shown in Patent Document 2 uses a material with high hydrogen sulfide gas permeability as the sealant layer. Furthermore, the casing material for all-solid-state batteries shown in Patent Document 3 uses a material that absorbs gas as the sealant layer. Furthermore, the casing material for all-solid-state batteries shown in Patent Document 4 is constructed by laminating a vapor-deposited film layer on the inner surface of the sealant layer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 6777276 [Patent Document 2] Patent No. 6747636 [Patent Document 3] Japanese Patent Publication No. 2020-187855 [Patent Document 4] Japanese Patent Publication No. 2020-187835 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, the conventional all-solid-state batteries described above have a problem in that there is a risk of leakage of gases such as hydrogen sulfide gas, which are produced by the reaction between the solid electrolyte and water.

[0009] On the other hand, all-solid-state batteries have higher resistance and generate more heat compared to liquid electrolytes because electron (ion) exchange occurs through the solid electrolyte during charging and discharging. However, all-solid-state batteries are thought to be unaffected by high-temperature environments, and currently, no consideration has been given to high-temperature countermeasures (cooling performance), including the aforementioned patent documents 1 to 4. However, as battery technology progresses towards higher output and capacity, it is quite predictable that improved cooling performance will be required for all-solid-state batteries in the future.

[0010] Preferred embodiments of the present invention have been made in view of the aforementioned and / or other problems in the related art. Preferred embodiments of the present invention can significantly improve upon existing methods and / or apparatus.

[0011] This invention has been made in view of the above-mentioned problems, and aims to provide an exterior material for an all-solid-state battery and an all-solid-state battery that can ensure sufficient cooling performance while preventing leakage of sulfur gas and the like.

[0012] Other objectives and advantages of the present invention will become apparent from the following preferred embodiments. [Means for solving the problem]

[0013] To solve the above problems, the present invention comprises the following means.

[0014] [1] An outer casing material for an all-solid-state battery for enclosing a solid-state battery body, comprising a base layer, a metal foil layer laminated on the inner surface side of the base layer, and a sealant layer laminated on the inner surface side of the metal foil layer, A heat-resistant gas barrier layer made of resin is provided between the metal foil layer and the sealant layer. An outer casing for an all-solid-state battery, characterized in that an opening is provided in the portion of the sealant layer corresponding to the solid-state battery body, and the heat-resistant gas barrier layer is arranged to be exposed on the inner side at the opening.

[0015] [2] The resin constituting the heat-resistant gas barrier layer has a water vapor transmission rate of 50 (g / m³) measured in accordance with JIS K7129-1 (humidity sensor method 40°C 90%Rh). 2 The casing material for all-solid-state batteries described in item 1 above, which is less than or equal to / day.

[0016] [3] The heat-resistant gas barrier layer is made of a resin whose melting point is 10°C or higher than that of the sealant layer, as described in paragraph 1 or 2 above.

[0017] [4] The resin constituting the heat-resistant gas barrier layer has a thermal conductivity of 0.2 W / m·K or more, and the exterior material for all-solid-state batteries according to any one of the preceding items 1 to 3.

[0018] [5] An all-solid-state battery characterized in that a solid battery body is enclosed in the exterior material for all-solid-state batteries according to any one of the preceding items 1 to 4.

[0019] [6] The all-solid-state battery according to claim 5, wherein the heat-resistant gas barrier layer and the solid battery body are in contact with each other.

Advantages of the Invention

[0020] According to the exterior material for all-solid-state batteries of Invention [1], a heat-resistant gas barrier layer is provided between the metal foil layer and the sealant layer, and an opening through which the heat-resistant gas barrier layer is exposed is formed in the portion of the sealant layer corresponding to the solid battery body. Therefore, the heat generated from the solid battery body is transmitted through the heat-resistant gas barrier layer to the metal foil layer 12 and radiated without being blocked by the sealant layer, so that sufficient cooling performance can be ensured. Further, in the present invention, since the heat-resistant gas barrier layer is disposed on the inner surface side of the metal foil layer, even if the solid electrolyte of the solid battery body reacts with moisture in the outside air to generate hydrogen sulfide gas or the like, the gas can be reliably prevented from leaking through the heat-resistant gas barrier layer.

[0021] According to the exterior material for all-solid-state batteries of Invention [2], since the water vapor transmission rate of the heat-resistant gas barrier layer is specified, the intrusion of moisture such as water vapor gas from the outside can be prevented by the gas permeation prevention action of the heat-resistant gas barrier layer. Therefore, the generation of hydrogen sulfide gas itself due to the reaction between the moisture and the solid electrolyte can be suppressed, and the leakage of hydrogen sulfide gas or the like can be more reliably prevented.

[0022] According to the exterior material for all-solid-state batteries of Invention [3], since the heat-resistant gas barrier layer has a high melting point, the melting and outflow of the heat-resistant gas barrier layer can be prevented during the thermal adhesion of the sealant layer, and gas leakage can be more reliably prevented.

[0023] The exterior material for all-solid-state batteries of the invention [4] can further improve cooling performance because the thermal conductivity of the gas barrier layer is specified.

[0024] According to the invention [5], since it specifies an all-solid-state battery using the exterior materials of the above inventions [1] to [4], the same effects as above can be obtained.

[0025] According to the invention [6], the solid battery body can be kept in a stable state. [Brief explanation of the drawing]

[0026] [Figure 1] Figure 1 is a schematic cross-sectional view showing an all-solid-state battery, which is an embodiment of this invention. [Figure 2] Figure 2 is an exploded view schematically showing the configuration of an all-solid-state battery according to an embodiment. [Modes for carrying out the invention]

[0027] Figure 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment of this invention, and Figure 2 is an exploded view schematically showing the configuration of the all-solid-state battery. As shown in both figures, the all-solid-state battery of this embodiment comprises an outer casing 1 which is configured as the casing of the all-solid-state battery, and a solid-state battery body 5 which is housed and sealed within the outer casing 1.

[0028] The exterior material 1 comprises a base material layer 11 positioned on the outermost side, a metal foil layer 12 laminated and bonded to the inner surface of the base material layer 11 via an adhesive layer, a heat-resistant gas barrier layer 21 laminated and bonded to the inner surface of the metal foil layer 12 via an adhesive layer, and a sealant layer 13 laminated and bonded to the inner surface of the heat-resistant gas barrier layer 21 via an adhesive layer 4. The sealant layer 13 is formed by removing the middle portion except for its outer peripheral edge, creating an opening 15, with only the outer peripheral edge remaining. In this exterior material 1, there is no adhesive layer 4 at the opening 15, and the heat-resistant gas barrier layer 21 is exposed to the inside through the opening 15.

[0029] In this embodiment, two rectangular outer casing materials 1,1 are stacked vertically via the solid battery body 5 with their sealant layers 13 facing each other at their outer edges, and the sealant layers 13 are bonded together in an airtight (sealed) state by heat bonding (heat sealing), thereby manufacturing an all-solid-state battery in which the solid battery body 5 is sealed and housed within a bag-shaped casing made of the outer casing materials 1,1.

[0030] In this all-solid-state battery, an opening 15 in the outer casing material 1 is located in the portion corresponding to the solid-state battery body 5, and the upper and lower surfaces of the solid-state battery body 5 are positioned to face the heat-resistant gas barrier layer 21 of the upper and lower outer casing materials 1 through the opening 15.

[0031] In addition, although not shown in the illustration, a tab lead is provided in the all-solid-state battery of this embodiment for drawing electricity. One end (inner end) of this tab lead is bonded and fixed to the solid-state battery body 5, the middle part passes through the outer peripheral edges (sealant layer 13) of the two outer casings 1,1, and the other end (outer end) is led out to the outside.

[0032] In this embodiment, the casing is formed by bonding two flat exterior materials 1,1 together. However, the invention is not limited to this, and in this invention, at least one of the two exterior materials may be pre-formed into a tray shape, and the tray-shaped exterior material may be bonded to the other tray-shaped or flat exterior material to form the casing.

[0033] The detailed configuration of the outer casing material 1 of the all-solid-state battery in this embodiment will be described below.

[0034] The base layer 11 of the exterior material 1 is composed of a heat-resistant resin film with a thickness of 5 μm to 50 μm. Suitable resins for this base layer 11 include polyamide, polyester (PET, PBT, PEN, etc.), polyolefin (PE, PP, etc.), etc.

[0035] The metal foil layer 12 has a thickness of 5 μm to 120 μm and has the function of blocking the intrusion of oxygen and moisture from the surface (outside). Suitable materials for this metal foil layer 12 include aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, etc. In this embodiment, the terms "aluminum," "copper," and "nickel" are used to include their alloys as well.

[0036] Furthermore, applying a plating treatment to the metal foil layer 12 reduces the risk of pinhole formation and further improves the function of blocking the intrusion of oxygen and moisture.

[0037] Furthermore, if the metal foil layer 12 is subjected to a chemical conversion treatment such as chromate treatment, its corrosion resistance is further improved, making it possible to more reliably prevent defects such as chipping, and also improving adhesion with the resin, thereby further enhancing durability.

[0038] The sealant layer 13 has a thickness of 10 μm to 100 μm and is composed of a heat-adhesive (heat-fusible) resin film. Suitable resins for this sealant layer 13 include polyethylene (LLDPE, LDPE, HDPE), polyolefins such as polypropylene, olefin copolymers, acid-modified products thereof, and ionomers, such as unoriented polypropylene (CPP, IPP).

[0039] As for the sealant layer 13, considering the extraction of electricity using tab leads, that is, considering the sealing and adhesion properties with respect to the tab leads, it is preferable to use a polypropylene resin (unoriented polypropylene film (CPP, IPP)).

[0040] Details regarding the method for forming the openings 15 in the sealant layer 13 will be explained later.

[0041] The heat-resistant gas barrier layer 21 is composed of a resin film having heat resistance and insulating properties. Preferably, the resin used to constitute this heat-resistant gas barrier layer 21 is polyamide (6-nylon, 66-nylon, MXD nylon, etc.), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), cellophane, polyvinylidene chloride (PVDC), or stretched propylene (OPP).

[0042] In this embodiment, it is preferable that the resin constituting the heat-resistant gas barrier layer 21 has a predetermined hydrogen sulfide (H2S) gas permeability. Specifically, the heat-resistant gas barrier layer 21 has a hydrogen sulfide gas permeability of 15 {cc·mm / (m³) in measurements conforming to JIS K7126-1. 2 It is preferable to use a resin with a minimum pressure of 10 cc / mm / (m²) or less. 2 It is preferable to use a resin with a minimum output of 4.0 {cc·mm / (m²)}. 2 It is preferable to use a resin with a pressure of 0.5 MPa or less. In other words, if the hydrogen sulfide gas permeability of the heat-resistant gas barrier layer 21 is set to the above-mentioned specific value or less, when hydrogen sulfide gas is generated by the reaction of the solid electrolyte material with moisture in the outside air, the heat-resistant gas barrier layer 21 can prevent the hydrogen sulfide gas from leaking to the outside. In other words, if the hydrogen sulfide gas permeability of the heat-resistant gas barrier layer 21 is too high, there is a risk that the generated hydrogen sulfide gas will leak to the outside through the exterior material 1 (heat-resistant gas barrier layer 21), which is undesirable.

[0043] For reference, the "D" in the unit for hydrogen sulfide gas permeability corresponds to "Day (24h)".

[0044] In this embodiment, the thickness (original thickness) of the heat-resistant gas barrier layer 21 is preferably set to 3 μm to 50 μm, and more preferably to 10 μm to 40 μm. That is, when the thickness of the heat-resistant gas barrier layer 21 is set within this range, the above-mentioned effect of suppressing the permeation of hydrogen sulfide gas and water vapor gas can be reliably obtained, and even if the sealant layer 13 melts and flows out due to thermal bonding, the heat-resistant gas barrier layer 21 can reliably ensure insulation. In other words, if the heat-resistant gas barrier layer 21 is too thin, there is a risk that the gas permeation suppression effect and insulation cannot be ensured, which is undesirable. Conversely, if the heat-resistant gas barrier layer 21 is too thick, not only is it not possible to thin the exterior material 1, but the effect of making it thicker than necessary cannot be fully obtained, which is also undesirable.

[0045] In this embodiment, it is preferable to use a resin film as the heat-resistant gas barrier layer 21. That is, since the entire film acts as a barrier layer, barrier cracks do not occur, unlike vapor-deposited films, and barrier properties can be improved.

[0046] Furthermore, the resin film constituting the heat-resistant gas barrier layer 21 can be an unoriented film or a slightly stretched film, and it is particularly preferable to use an unoriented film. In other words, when an unoriented film is used, the moldability and gas barrier properties can be further improved.

[0047] The heat-resistant gas barrier layer 21 of this embodiment has good insulating properties, and good insulating properties are obtained even after the solid battery body 5 is sealed by heat bonding with the exterior material 1 of this embodiment.

[0048] In this embodiment, the adhesive constituting the adhesive layer 4 that bonds the insulating layer 21 and the sealant layer 13 can be a two-component curing type, an energy ray (UV, X-ray, etc.) curing type, or any other curing type. Among these, urethane-based adhesives, olefin-based adhesives, acrylic-based adhesives, epoxy-based adhesives, etc., can be suitably used. Furthermore, the thickness of the adhesive layer 4 is set to 2 μm to 5 μm.

[0049] In this embodiment, the same adhesive as the adhesive used in the adhesive layer 4 can be suitably used as the adhesive for bonding the base layer 11 and the metal foil layer 12, and the metal foil layer 12 and the insulating layer 21, and it is preferable to set the thickness to be the same.

[0050] As previously described, the exterior material 1 of this embodiment has an opening 15 formed in the sealant layer 13. This opening 15 is formed in the portion corresponding to the solid battery body 5, and the sealant layer 13 is positioned in the portion corresponding to the heat seal portion (sealing portion).

[0051] In this embodiment, no adhesive layer 4 is provided at the opening 15 of the exterior material 1, and the heat-resistant gas barrier layer 21 is exposed to the inside through the opening 15. When the all-solid-state battery is manufactured, the heat-resistant gas barrier layer 21 is positioned to face the solid-state battery body 5. In this embodiment, it is sufficient that at least a part of the solid-state battery body 5 is in contact with the heat-resistant gas barrier layer 21. Furthermore, a part of the sealant layer 13 may be positioned corresponding to the solid-state battery body 5, for example, a part of the sealant layer 13 may be in contact with the solid-state battery body 5. However, heat dissipation can be improved if the solid-state battery body 5 is not in contact with the sealant layer 13.

[0052] In this embodiment, it is preferable that almost the entire upper and lower surfaces (inner and outer surfaces) of the solid battery body 5 are in contact with the heat-resistant barrier layer 21. In this case, the solid battery body 5 is held in a stable state via the heat-resistant barrier layer 21, and displacement of the solid battery body 5 can be prevented.

[0053] Furthermore, in this embodiment, the adhesive layer 4 is not provided in the opening 15, but the invention is not limited to this, and in the present invention, the adhesive 4 may be provided in at least a part of the opening 15. However, heat dissipation can be improved by not providing the adhesive layer 4 as in this embodiment.

[0054] In this embodiment, the opening 15 of the exterior material 1 is formed, for example, by cutting out the middle portion of the sealant layer 13 laminated over the entire area of ​​the heat-resistant gas barrier layer 21, while the sealant layer 13 at the outer edge remains intact.

[0055] In this embodiment, when forming the sealant layer 13 on the heat-resistant gas barrier layer 21, an adhesive layer 4 is applied to the inner surface of the resin film that serves as the heat-resistant gas barrier layer 21 using a gravure roll or the like, and the resin film that serves as the sealant layer 13 is attached via the adhesive layer 4. However, when applying the adhesive to the heat-resistant gas barrier layer 21 using a gravure roll or the like, an uncoated area is formed in the region where the opening is to be formed, where the adhesive is not applied. Then, the resin film for the sealant layer is attached to the heat-resistant gas barrier layer 21 having this uncoated area and dried. After that, the resin film for the sealant layer in the uncoated area is cut out with a laser cutter or roll blade or the like to form the opening 15 (first forming method).

[0056] In the second forming method, before applying adhesive to the heat-resistant gas barrier layer 21, release paper is temporarily attached to the area in the heat-resistant gas barrier layer 21 where the opening is to be formed. In this state, adhesive is applied to the heat-resistant gas barrier layer 21 using a gravure roll or the like, and a resin film for the sealant layer is attached and dried. After that, the resin film for the sealant layer corresponding to the temporarily attached release paper is cut out together with the adhesive and release paper using a roll blade or the like to form the opening 15. When using this second forming method, only the resin film for the sealant layer may be removed, or only the resin film for the sealant layer and the adhesive may be removed. In other words, the adhesive and release agent may be left in place, or only the adhesive may be left in place.

[0057] Other forming methods include forming through holes as openings 15 in the resin film for the sealant layer before bonding it to the heat-resistant gas barrier layer 21, and then attaching the resin film for the sealant layer with the openings to the heat-resistant gas barrier layer 21 via an adhesive (other forming methods). However, with these other forming methods, it is difficult to apply the adhesive evenly, and it is difficult to accurately and precisely attach the resin film for the sealant layer with the openings. Therefore, in this embodiment, it is preferable to adopt the first and second forming methods described above.

[0058] As described above, in the all-solid-state battery of this embodiment, a heat-resistant gas barrier layer 21 is formed between the metal foil layer 12 and the sealant layer 13 of the outer material 1, and an opening 15 is formed in the portion of the sealant layer 13 corresponding to the solid-state battery body 5 through which the heat-resistant gas barrier layer 21 is exposed. Therefore, the heat generated from the solid-state battery body 5 is not blocked by the sealant layer 13, but is transferred to the metal foil layer 12 via the heat-resistant gas barrier layer 21 and dissipated. Accordingly, sufficient cooling can be ensured, and malfunctions due to high temperatures can be reliably prevented.

[0059] In this embodiment, it is preferable to use a resin with a thermal conductivity of 0.2 W / m·K or higher as the resin constituting the heat-resistant gas barrier layer 21. That is, by adopting this configuration, the heat transfer performance of the heat-resistant gas barrier layer 21 can be sufficiently ensured, thereby further improving the cooling performance of the solid battery body 5.

[0060] Furthermore, in this embodiment, since the heat-resistant gas barrier layer 21 is arranged on the inner surface side of the metal foil layer 12, even if the solid electrolyte of the solid battery body 5 reacts with moisture in the outside air to generate hydrogen sulfide gas, etc., the heat-resistant gas barrier layer 21 can reliably prevent the gas from leaking out. In addition, the gas permeability prevention effect of the heat-resistant gas barrier layer 21 prevents the intrusion of moisture such as water vapor from the outside, so the generation of hydrogen sulfide gas itself due to the reaction of that moisture with the solid electrolyte can also be suppressed, and the leakage of hydrogen sulfide gas, etc. can be prevented more reliably.

[0061] In this embodiment, the resin constituting the heat-resistant gas barrier layer 21 has a water vapor gas transmission rate of 50 g / m³ measured in accordance with JIS K7129-1 (humidity sensor method, 40°C, 90% Rh). 2 It is preferable to adopt a configuration of less than or equal to / day. In other words, by adopting this configuration, the intrusion of moisture by the heat-resistant gas barrier layer 21 can be prevented more reliably, and the generation and leakage of hydrogen sulfide gas can be prevented more reliably.

[0062] Furthermore, in this embodiment of the all-solid-state battery, although there is no sealant layer 13 between the solid-state battery body 5 and the metal foil layer 12, an insulating heat-resistant gas barrier layer 21 is placed between them, so insulation can be reliably ensured by the heat-resistant gas barrier 21.

[0063] In this embodiment, the resin constituting the heat-resistant gas barrier layer 21 must have a melting point at least 10°C higher than the resin constituting the sealant layer 13. In other words, if the heat-resistant gas barrier layer 21 has a high melting point, even if the sealant layer 13 is melted when the exterior material 1 is heat-bonded, the melting and leakage of the heat-resistant gas barrier layer 21 can be prevented, thus more reliably obtaining the gas permeation suppression effect and insulation properties provided by the heat-resistant gas barrier layer 21.

[0064] Furthermore, in this embodiment of the all-solid-state battery, since the sealant layer 13 is not formed in the portion of the outer casing material 1 corresponding to the solid battery body 5, the space for housing the solid battery body 5 can be made larger (thicker). Therefore, in this embodiment of the all-solid-state battery, a larger solid battery body 5 can be housed without changing the external dimensions of the casing (outer casing material 1) compared to conventional all-solid-state batteries, thus enabling thinner construction while increasing output power and capacity. [Examples]

[0065] [Table 1]

[0066] <Example 1> 1. Fabrication of exterior materials A 40 μm thick aluminum foil (A8021-O), which served as the metal foil layer 12, was coated on both sides with a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium(III) salt compound, water, and alcohol. The solution was then dried at 180°C to form a chemical conversion film. The amount of chromium deposited on this chemical conversion film was 10 mg / m² per side. 2 That was the case.

[0067] Next, a 15 μm thick biaxially oriented nylon 6 (ONY-6) film was dry-laminated (bonded) to one side (outer surface) of the chemically treated aluminum foil (metal foil layer 12) via a two-component curing urethane adhesive (3 μm) as a base layer 11.

[0068] Next, as shown in Table 1, a 9 μm thick PET film was dry-laminated to the other side (inner surface) of the aluminum foil after dry lamination via a two-component curing urethane adhesive (3 μm) to form a heat-resistant gas barrier layer 21.

[0069] Next, a two-component curing urethane-based adhesive (3 μm) as the adhesive layer 4 was gravure coated onto the inner surface of the PET film, which served as the heat-resistant gas barrier layer 21. At this time, the rectangular-shaped area where the opening was to be formed was left uncoated, and the adhesive was applied only to the outer periphery of the opening formation area (heat-sealed area: area where the sealant layer remained).

[0070] Next, as the sealant layer 13, a 40 μm thick CPP film containing a lubricant (such as erucic acid amide) was placed on the inner surface of the heat-resistant gas barrier layer 21, to which the adhesive had been applied only to the required areas. This film was then dry-laminated by sandwiching it between a rubber nip roll and a laminating roll heated to 100°C and pressing it together to obtain a laminate constituting the exterior material 1.

[0071] Next, this laminate was wound onto a roll shaft, and then aged at 40°C for 10 days. After aging, a CPP film for the sealant layer was cut from the laminate along the outer edge of the uncoated portion using a laser cutter, forming an opening 15 in the middle of the sealant layer 13 to obtain the exterior material sample of Example 1. In this exterior material sample, the heat-resistant gas barrier layer 21 is positioned so that it is exposed on the inner side through the opening 15.

[0072] 2. Measurement of water vapor transmission rate The water vapor transmission rate of the resin film used for the heat-resistant gas barrier layer 21 in the preparation of the exterior material sample in Example 1 was measured in accordance with JIS K7129-1 (humidity sensor method, 40°C, 90%Rh). The results are shown in Table 1.

[0073] 3. Measurement of thermal conductivity The thermal conductivity of the resin film used for the heat-resistant gas barrier layer 21 in the preparation of the exterior material sample in Example 1 was measured using a steady-state heat flow meter (HFM) method. The results are shown in Table 1.

[0074] 4. Measurement of H2S gas permeability, etc., of resin films The hydrogen sulfide (H2S) gas permeability of the resin film used for the heat-resistant gas barrier layer 21 in the preparation of the exterior material sample in Example 1 was measured in accordance with JIS K7126-1. The results are shown in Table 1.

[0075] 5. Evaluation of cooling performance (cooling effect) Two exterior material samples of Example 1, each measuring 100mm x 100mm, were prepared. The opening 15 in these exterior material samples is square and measures 60mm x 60mm.

[0076] These two outer packaging material samples were placed facing each other with their openings 15 facing inward, and the two overlapping outer packaging material samples were heat-sealed at a width of 5 mm 10 mm from the edge on three of the four sides to create a three-sided bag.

[0077] In a room temperature environment (25°C), 80 ml of 80°C hot water was poured into the three-sided bag through its opening. A thermometer was then inserted, the opening was closed with a binder clip, and the temperature change of the hot water was measured for 3 minutes. The temperature immediately after the hot water was poured and the temperature after 3 minutes are shown together in Table 1.

[0078] <Example 2> The sample for Example 2 was prepared in the same manner as in Example 1, except that an ONY-6 film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0079] <Example 3> The sample for Example 3 was prepared in the same manner as in Example 1, except that an OPP film (biaxially oriented polypropylene film) was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0080] <Example 4> The sample for Example 4 was prepared in the same manner as in Example 1, except that a 10 μm thick polyvinylidene chloride (PVDC) film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0081] <Example 5> The sample for Example 5 was prepared in the same manner as in Example 1, except that a PVDC film with a thickness of 15 μm was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 12.

[0082] <Example 6> The sample for Example 6 was prepared in the same manner as in Example 1, except that a 25 μm thick PVDC film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0083] <Example 7> The sample for Example 7 was prepared in the same manner as in Example 1, except that a heat-resistant gas barrier layer 21 was formed by coating the other side (inner surface) of the aluminum foil for the metal foil layer with PVDC to a thickness of 2 μm. The same measurements (evaluations) were performed. The results are shown in Table 1.

[0084] <Example 8> The sample for Example 8 was prepared in the same manner as in Example 1, except that a PVDC film with a thickness of 50 μm was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 12.

[0085] <Comparative Example 1> A sample for Comparative Example 1 was prepared in the same manner as in Example 1, except that a sealant layer 13 was formed over the entire inner surface of the heat-resistant gas barrier layer 21, meaning that no openings 15 were formed in the sealant layer 13. The same measurements (evaluations) were then performed. The results are shown in Table 1.

[0086] <Comparative Example 2> A sample for Comparative Example 2 was prepared in the same manner as for Comparative Example 1, except that an ONY-6 film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0087] <Comparative Example 3> A sample for Comparative Example 3 was prepared in the same manner as for Comparative Example 1, except that an OPP film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were performed. The results are shown in Table 1.

[0088] <Overall assessment> As is clear from Table 1, the exterior material samples of Examples 1 to 8 related to the present invention had a temperature of less than 40°C after 3 minutes, demonstrating appropriate and high cooling performance (cooling effect).

[0089] In contrast, the exterior material samples of Comparative Examples 1 to 3, which deviate from the gist of the present invention, had a temperature of 40°C or higher after 3 minutes, and were unable to achieve high cooling performance.

[0090] This application is accompanied by a priority claim from Japanese Patent Application No. 2021-132360, filed on August 16, 2021, and the disclosures thereof constitute a part of this application.

[0091] The terms and expressions used herein are for illustrative purposes only and not intended to be restrictive, and should be understood as not excluding any equivalents of the features shown and described herein, and allowing for various modifications within the claimed scope of this invention. [Industrial applicability]

[0092] The exterior material for all-solid-state batteries of this invention can be suitably used as a casing material for housing the solid-state battery body. [Explanation of symbols]

[0093] 1: Exterior materials 11: Base material layer 12: Metal foil layer 13: Sealant layer 15: Opening 21: Heat-resistant gas barrier layer 5: Solid-state battery unit

Claims

1. An outer casing material for an all-solid-state battery, comprising a base layer, a metal foil layer laminated on the inner surface side of the base layer, and a sealant layer laminated on the inner surface side of the metal foil layer, for enclosing a solid-state battery body, A heat-resistant gas barrier layer made of resin is provided between the metal foil layer and the sealant layer. An outer casing for an all-solid-state battery, characterized in that an opening is provided in the portion of the sealant layer corresponding to the solid-state battery body, and the heat-resistant gas barrier layer is arranged to be exposed on the inner side at the opening.

2. The resin constituting the heat-resistant gas barrier layer has a water vapor transmission rate of 50 g / m³, measured in accordance with JIS K7129-1 (humidity sensor method, 40°C, 90% Rh). ２ An outer casing material for an all-solid-state battery according to claim 1, wherein the value is less than or equal to / day.

3. The exterior material for an all-solid-state battery according to claim 1 or 2, wherein the heat-resistant gas barrier layer is made of a resin whose melting point is 10°C or higher than that of the sealant layer.

4. The resin constituting the heat-resistant gas barrier layer has a thermal conductivity of 0.2 W / m·K or more, as described in any one of claims 1 to 3, for use as an exterior material for all-solid-state batteries.

5. A solid-state battery characterized in that a solid-state battery body is enclosed in an outer casing material for a solid-state battery as described in any one of claims 1 to 4.

6. The all-solid-state battery according to claim 5, wherein the heat-resistant gas barrier layer and the solid-state battery body are in contact.

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