Inner bag film for semi-solid battery and semi-solid battery

Abstract

An inner bag film for a semi-solid battery, which is disposed between an exterior material of the semi-solid battery and a battery element, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The inner bag film for a semi-solid battery, wherein the substrate comprises a polyolefin.

Description

[Technical field]

[0001] The present disclosure relates to an inner bag film for a semi-solid battery and a semi-solid battery. [Background technology]

[0002] Conventionally, various types of electricity storage devices have been developed, and in all electricity storage devices, exterior materials are essential components for sealing electricity storage device elements such as electrodes, electrolytes, etc. Conventionally, metallic exterior materials have been widely used as exterior materials for electricity storage devices.

[0003] Meanwhile, in recent years, various shapes as well as thinner and lighter weight are required for electricity storage devices along with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc. However, the metallic exterior materials for electricity storage devices that have been widely used in the past have the drawbacks of being difficult to keep up with the diversification of shapes and also having limitations in terms of weight reduction.

[0004] In view of this, a film-like laminate in which a base layer / barrier layer / adhesive layer / thermally adhesive resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thin and lightweight (see, for example, Patent Document 1).

[0005] In such an exterior material for an electricity storage device, a recess is generally formed by cold forming, and electricity storage device elements such as electrodes and an electrolyte are placed in the space formed by the recess, and the heat-sealable resin layer is then heat-sealed to obtain an electricity storage device in which the electricity storage device elements are housed inside the exterior material for an electricity storage device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-287971 A [Patent Document 2] International Publication No. 2019 / 087956 Summary of the Invention [Problem to be solved by the invention]

[0007] Semi-solid batteries that use semi-solid electrodes are known as power storage devices (see Patent Document 2). Semi-solid batteries use semi-solid electrodes that have fluidity, and the electrodes tend to lose their shape when dried. For this reason, in semi-solid batteries, the battery element is kept in its shape by an exterior material (packaging body).

[0008] For example, Patent Document 2 discloses a semi-solid battery (electrochemical cell) including a power generating element including a semi-solid positive electrode, a semi-solid negative electrode, a separator located between the positive electrode and the negative electrode, a positive electrode current collector electrically connected to the positive electrode, and a negative electrode current collector electrically connected to the negative electrode, and a packaging body containing the power generating element, the packaging body having holes opening to the inside and outside.

[0009] As with general power storage devices, in semi-solid batteries, it is possible to connect a plurality of cells (single cells) to form a module (battery assembly), which is then housed in a package to form one large semi-solid battery. When a semi-solid battery is made into a module, each cell may have a battery element housed in an inner bag, and these cells may be further housed in a package. In such a configuration, if the plurality of cells are not fixed in the package, the cells may move in the package during use of the semi-solid battery, and the cells, the package, etc. may be damaged. Therefore, it is desirable to fix the cells in the package together. The present inventors thought that in order to fix the plurality of cells together, it would be effective to use an inner bag film to form the inner bag, impart heat fusion to the base material constituting the outside of the inner bag film, and heat fusion the outsides of the inner bags together, and set a new problem of imparting heat fusion to the base material of the inner bag film.

[0010] Furthermore, as described above, in a film-like exterior material for an electricity storage device, generally, a recess is formed by cold forming, and an electricity storage device element such as an electrode or an electrolyte is disposed in the space formed by the recess, and a heat-sealable resin layer is heat-sealed to obtain an electricity storage device in which the electricity storage device element is housed inside the exterior material for an electricity storage device. For example, when such an exterior material is applied to a semi-solid battery, the inner bag film is also required to have excellent formability.

[0011] Under these circumstances, the main objective of the present disclosure is to provide a novel inner bag film that is placed between the exterior material and the battery element of a semi-solid battery, which allows the base materials of the inner bag film to be easily heat-sealed to each other and has excellent formability. [Means for solving the problem]

[0012] The inventors of the present disclosure have conducted intensive research to solve the above problems. As a result, they have found that in an inner bag film for a semi-solid battery, which is arranged between an exterior material of a semi-solid battery and a battery element, the inner bag film is composed of a laminate including at least a base material and an adhesive layer, and the base material contains polyolefin, so that the base materials of the inner bag film can be easily heat-sealed to each other and the moldability is excellent. Furthermore, since the base materials of the inner bag film can be easily heat-sealed to each other, for example, it has been found that multiple cells containing battery elements of a semi-solid battery can be prepared in an inner bag formed by the inner bag film, and the base materials of the inner bag located on the outside of each cell are heat-sealed to each other, thereby fixing the multiple cells in the package by heat fusion.

[0013] The present disclosure has been completed based on these findings and through further investigations. That is, the present disclosure provides the invention of the following aspects. An inner bag film for a semi-solid battery, which is disposed between an exterior material of the semi-solid battery and a battery element, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The inner bag film for a semi-solid battery, wherein the substrate comprises a polyolefin. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide a novel inner bag film that is disposed between an exterior material and a battery element of a semi-solid battery, and that allows the base materials of the inner bag film to be easily heat-sealed to each other and has excellent formability. Also, according to the present disclosure, it is possible to provide a semi-solid battery using the inner bag film. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic diagram showing an example of a cross-sectional structure of a packaging film for a semi-solid battery according to the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a cross-sectional structure of an exterior material used in the semi-solid battery of the present disclosure. [Diagram 3] FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of a semi-solid battery according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The inner bag film for a semi-solid battery of the present disclosure is disposed between an exterior material of the semi-solid battery and a battery element, and is composed of a laminate including at least a substrate and an adhesive layer, and is characterized in that the substrate contains a polyolefin. By virtue of having this configuration, the inner bag film for a semi-solid battery of the present disclosure can easily heat-seal the substrates of the inner bag film and has excellent formability.

[0017] The inner bag film for semi-solid batteries and the semi-solid battery of the present disclosure will be described in detail below. In the present disclosure, the numerical range indicated by "~" means "more than or equal to" or "less than or equal to". For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in the present disclosure in stages, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and the upper limit, the upper limit and the lower limit, or the lower limit and the lower limit described separately may be combined to form a numerical range. In addition, in the numerical ranges described in the present disclosure, the upper limit or the lower limit described in a certain numerical range may be replaced with a value shown in the examples.

[0018] In addition, in this disclosure, "semi-solid" refers to a material that is a mixture of a liquid phase and a solid phase, such as, for example, a particle suspension, a colloidal suspension, an emulsion, a gel, or a micelle, and a semi-solid battery is one that utilizes semi-solid electrodes.

[0019] 1. Inner bag film for semi-solid batteries The inner bag film for a semi-solid battery of the present disclosure is composed of a laminate including at least a substrate and an adhesive layer. Furthermore, the substrate includes polyolefin. That is, the inner bag film for a semi-solid battery of the present disclosure is a laminate film including at least a substrate including polyolefin and an adhesive layer. As shown in the schematic diagram of FIG. 3, the inner bag film for a semi-solid battery 1 of the present disclosure is disposed between an exterior material 3 and a battery element 4 of a semi-solid battery 10.

[0020] As described above, in the case of semi-solid batteries, similarly to general power storage devices, it is conceivable to connect a plurality of cells (single cells) to form a module (battery assembly), which is then housed in a package to form a single large semi-solid battery. In such a semi-solid battery module, since a plurality of cells are housed in the package, it is desirable to fix the plurality of cells together.

[0021] As described above, in a film-like exterior material for an electricity storage device, generally, a recess is formed by cold forming, and an electricity storage device element such as an electrode or an electrolyte is disposed in the space formed by the recess, and a heat-sealable resin layer is heat-sealed to obtain an electricity storage device in which the electricity storage device element is housed inside the exterior material for an electricity storage device. For example, when such an exterior material is applied to a semi-solid battery, the inner bag film is also required to have excellent formability.

[0022] The inner bag film of the present disclosure uses a polyolefin, which has heat-sealing properties and excellent formability, as the base material, so that the base materials can be fixed together by heat fusion and the inner bag film has excellent formability.

[0023] In the semi-solid battery 10 of the present disclosure, the battery element 4 is housed in an inner bag formed by an inner bag film 1, and the inner bag housing the battery element 4 is housed in a package formed by an exterior material 3. The battery element 4 preferably has a structure sealed (hermetically sealed) by the inner bag film 1. In addition, the battery element 4 and the packaging film 1 preferably have a structure sealed (hermetically sealed) by the exterior material 3. That is, in the semi-solid battery 10, the battery element 4 preferably has a structure doubly sealed by the inner bag film 1 and the exterior material 3.

[0024] The battery element 4 can be sealed in the inner bag by covering the battery element 4 with the inner bag film 1 and heat-sealing the flange portion of the inner bag film 1. Furthermore, the inner bag in which the battery element 4 is sealed can be covered with an exterior material 3 and the flange portion of the exterior material 3 can be heat-sealed to seal the inner bag in the package.

[0025] The semi-solid battery 10 may be a package in which a plurality of inner bags each containing a battery element 4 are housed. In this case, at least a portion of the inner bags each containing a battery element 4 can be fixed together by heat fusion. Specifically, at least two inner bags can be fixed together by heat fusion of the base materials 11 of the inner bag film 1 constituting the inner bag. The position at which the packages are heat fused together is not particularly limited, and examples of the position include the periphery 30a of the inner bag, the upper surface of the inner bag, and the lower surface of the inner bag. In addition, it is not essential to heat fusion all the inner bags contained in the package, but from the viewpoint of sufficiently fixing the inner bags, it is preferable to heat fusion all the adjacent inner bags together.

[0026] For example, as shown in FIG. 3, in the semi-solid battery 10 of the present disclosure, the battery element 4 is covered with the inner bag film 1 to form each cell 30. Furthermore, the multiple cells 30 are covered with the exterior material 3. For example, in FIG. 3, the inner bag (cell 30) containing the battery element 4 is covered with the exterior material 3 so that a flange portion (peripheral portion 3a of the exterior material 3) of the exterior material 3 is formed near the periphery of the inner bag (cell 30) containing the battery element 4, and the flange portion of the exterior material 3 is heat-sealed to form a package containing the inner bag (cell 30). In this way, in the present disclosure, the inner bag containing the battery element 4 can be the cell 30. Note that the use of the inner bag film 1 of the present disclosure is not limited to the inner bag of the cell (single cell), and there is no particular limit to the use of the inner bag film 1 as long as it is disposed between the exterior material 3 and the battery element 4 of the semi-solid battery 10.

[0027] In the semi-solid battery 10 shown in the schematic diagram of Fig. 3, two cells 30 are housed in a package formed by an exterior material 3, and in each cell 30, a battery element 4 is housed in an inner bag formed by an inner bag film 1. When the semi-solid battery 10 is made into a module, the number of cells in the package may be two or more, and for example, 2 to 20 cells are housed in the package.

[0028] 3, each inner bag is composed of two inner bag films 1. In each cell 30, the adhesive layers 12 of the two inner bag films 1 are bonded to each other at the position of the flange portion 30a, thereby sealing the battery element 4 in the inner bag. The inner bag may be composed of one inner bag film, or two or more inner bag films.

[0029] In FIG. 3, the cells 30 are fixed together by heat sealing the base material 11 of the inner bag film 1 that constitutes the outer surface of the inner bag at the flange portion of the inner bag (the peripheral portion 30a of the inner bag).

[0030] The inner bag film 1 is used with the adhesive layer 12 described below facing inside (the surface in contact with the battery element 4). The exterior material 3 is used with the heat-sealable resin layer 35 described below facing inside (the surface in contact with the inner bag film 1).

[0031] As shown in Fig. 3, the metal terminal 2 protrudes outside the exterior material 3. The metal terminal 2 is connected to each of the positive and negative electrodes of the battery element 4. Fig. 3 shows a schematic diagram of an electrode 40 connected from the battery element 4 to the metal terminal 2. An adhesive film 21 for a metal terminal can be disposed between the metal terminal 2 and the exterior material 3. By disposing the adhesive film 21 for a metal terminal, the adhesion between the metal terminal 2 and the heat-sealable resin layer 35 of the exterior material 3 can be improved.

[0032] As shown in Fig. 3, in the semi-solid battery 10, the inner bag film 1 (the adhesive layer 12) can be adhered to the electrode 40 at positions where the electrode 40 is present, and the inner bag films 1 (the adhesive layers 12) can be adhered to each other at positions where the electrode 40 is not present. In order to adhere the inner bag film 1 to the electrode 40, it is preferable that the adhesive layer 12 has adhesiveness to metal. Also, in the semi-solid battery 10, in positions where the metal terminal 2 is present, the exterior material 3 (the heat-sealable resin layer 35) can be adhered to the metal terminal 2 via the adhesive film 21 for metal terminal, and in positions where the metal terminal 2 is not present, the exterior materials 3 (the heat-sealable resin layer 35) can be adhered to each other.

[0033] Although not shown in the drawings, in the semi-solid battery 10, an end of the inner bag film 1 (at least a part of the peripheral portion 30a (flange portion) of the inner bag) may be located at the flange portion (peripheral portion 3a of the outer bag 3) of the outer bag 3. Specifically, the inner bag may be arranged so that the end of the inner bag film 1 is present at least a part of the position where the heat-sealable resin layers 35 of the outer bag 3 are heat-sealed to each other and / or at least a part of the position where the heat-sealable resin layer 35 of the outer bag 3 is adhered to the metal terminal 2. With such an arrangement, it is possible to further firmly fix the inner bag by heat-sealing the base material 11 of the inner bag film 1 and the heat-sealable resin layer 35 of the outer bag 3.

[0034] When the inner bag film 1 is located at the flange portion (peripheral edge portion 3a of the outer bag material 3) of the outer bag material 3, the adhesive layer 12 of the inner bag film 1 preferably has heat fusion properties. Also, the adhesive layers 12 of the inner bag film 1 preferably have heat fusion properties with each other. Also, as described above, the adhesive layer 12 of the inner bag film 1 preferably has adhesion to metal.

[0035] The inner bag film 1 for a semi-solid battery according to the present disclosure is composed of two or more layers, for example, as shown in Fig. 1. Fig. 1 shows a schematic cross-sectional view of the inner bag film 1 for a semi-solid battery composed of a laminate in which a substrate 11 arranged on the exterior material 3 side and an adhesive layer 12 arranged on the battery element 4 are laminated.

[0036] When the inner bag film 1 is composed of two or more layers, at least one of the two or more layers is a substrate 11 and at least one of the layers is an adhesive layer 12. The substrate 11 constitutes one surface of the inner bag film 1, and the adhesive layer 12 constitutes the other surface of the inner bag film 1. The inner bag film 1 is preferably composed of two to four layers, more preferably two to three layers, and even more preferably two layers.

[0037] In addition, in the manufacturing process of a semi-solid battery, gases such as CO2 are generated from the battery element during the initial charge / discharge process, aging process, etc. In addition, semi-solid batteries use semi-solid electrodes that have fluidity, and the electrodes are prone to losing their shape when dried. For this reason, in a semi-solid battery, the battery element is housed in an exterior material (packaging body), and the initial charge / discharge process, aging process, etc. are performed while the battery element is in a shape-retaining state. When the initial charge / discharge process and aging process are performed while the battery element is housed in an exterior material (packaging body), it is necessary to take measures such as providing holes in the packaging body to release the generated gas. However, when holes are provided in the packaging body, although the gas generated from the battery element can be released during the manufacturing of the semi-solid battery, there is a problem that water vapor and the like are likely to penetrate through the holes in the packaging body after the battery is manufactured as a semi-solid battery.

[0038] In contrast, the polyolefin contained in the base material of the inner bag film of the present disclosure has excellent CO2 permeability, which makes it possible to suitably release CO2 gas generated from the battery element housed in the inner bag film (more specifically, the battery element housed in the inner bag formed by the inner bag film) to the outside.

[0039] In order to more suitably exert the effects of the present invention, the inner bag film 1 for a semi-solid battery of the present disclosure has a CO2 permeability of preferably about 6,000 cc / m2 at a temperature of 23°C and a relative humidity of 0% RH for 24 hours. 2 More preferably, about 8,000cc / m 2 More preferably, about 10,000 cc / m 2 The upper limit of the CO2 permeability is, for example, about 30,000cc / m 2 degree, 20,000cc / m 2 The preferred range of CO2 permeability is 6,000 to 30,000 cc / m 2 degree, 6,000~20,000cc / m 2 Approximately 8,000~30,000cc / m 2 degree, 8,000~20,000cc / m 2 degree, 10,000~30,000cc / m 2degree, 10,000~20,000cc / m 2 The degree of

[0040] Furthermore, from the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the thickness (total thickness) of the inner bag film 1 for a semisolid battery of the present disclosure is preferably 7 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm or less, and preferred ranges include about 7 to 30 μm, about 7 to 25 μm, about 7 to 20 μm, about 10 to 30 μm, about 10 to 25 μm, about 10 to 20 μm, about 15 to 30 μm, about 15 to 25 μm, and about 15 to 20 μm.

[0041] In addition, the inner bag film 1 for a semi-solid battery of the present disclosure is preferably not provided with holes for gas permeation. This is because the inner bag film 1 of the present disclosure has excellent CO2 permeability, so there is no need to provide such holes, and if the inner bag in the semi-solid battery 10 has holes, water vapor will easily penetrate from the outside.

[0042] From the viewpoint of optimally exerting the effects of the present invention, it is preferable that the inner bag film 1 does not have a metal layer. This is because the presence of a metal layer even in a part of the inner bag film 1 inhibits CO2 permeability. The metal layer means a layer formed of a metal, and examples thereof include a metal foil and a metal plate, and the thickness of the metal foil is, for example, about 10 to 200 μm, and the thickness of the metal plate is, for example, about 200 μm to several mm.

[0043] The inner bag film 1 for semi-solid batteries may contain various plastic compounding agents and additives for the purpose of improving or modifying, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mold resistance, electrical properties, strength, etc. The content may be any amount from a trace amount to several tens of percent depending on the purpose. In the above, typical additives may include, for example, antiblocking agents, lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, modifying resins, etc.

[0044] (Base material 11) The base material 11 contained in the inner bag film 1 contains polyolefin. The base material 11 may contain only one type of polyolefin, or may contain two or more types of polyolefin.

[0045] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more kinds. Among these, polypropylene is particularly preferred because it has excellent heat fusion properties, CO2 permeability, and heat resistance.

[0046] Furthermore, from the viewpoint of more optimally exerting the effects of the invention of the present disclosure, the base material 11 is preferably formed from a polyolefin film such as a polyethylene film or a polypropylene film, more preferably from a stretched polyolefin film such as a stretched polyethylene film or a stretched polypropylene film, and particularly preferably from a stretched polypropylene film.

[0047] The substrate 11 preferably constitutes one surface of the inner bag film 1 (the surface opposite to the adhesive layer 12). The substrate 11 preferably contains polyolefin, and further, the heat-sealable resin layer 35 of the exterior material 3 preferably contains polyolefin. When the heat-sealable resin layer 35 and the substrate 11 contain the same type of resin, namely polyolefin, the heat-sealable resin layer 35 and the substrate 11 can be suitably heat-sealed. Then, in the semi-solid battery 10, by arranging the heat-sealable resin layer 35 of the exterior material 3 and the substrate 11 of the inner bag film 1 so that they are in contact with each other, the heat-sealable resin layer 35 of the exterior material 3 and the substrate 11 of the inner bag film 1 can be heat-sealed to fix the inner bag film 1 in the exterior material 3.

[0048] The substrate 11 preferably has a CO2 permeability of about 6,000 cc / m2 at a temperature of 23°C and a relative humidity of 0% RH for 24 hours. 2 More preferably, about 8,000cc / m 2 More preferably, about 10,000 cc / m 2 The upper limit of the CO2 permeability is, for example, about 30,000cc / m 2 Approximately 20,000cc / m 2 The preferred range of the CO2 permeability is 6,000 to 30,000 cc / m 2 degree, 6,000~20,000cc / m 2 Approximately 8,000~30,000cc / m 2 degree, 8,000~20,000cc / m 2 degree, 10,000~30,000cc / m 2 degree, 10,000~20,000cc / m 2In addition, polyester film and polyvinylidene chloride have a CO2 permeability of 2,000cc / m 2 The following is the result.

[0049] From the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the thickness of the substrate 11 is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm or less, and preferred ranges include about 5 to 30 μm, about 5 to 25 μm, about 5 to 20 μm, about 10 to 30 μm, about 10 to 25 μm, about 10 to 20 μm, about 15 to 30 μm, about 15 to 25 μm, and about 15 to 20 μm.

[0050] (adhesive layer 12) The inner bag film 1 includes an adhesive layer 12. The adhesive layer 12 constitutes one surface of the inner bag film 1, and is a layer disposed on the battery element 4 side.

[0051] The adhesive layer 12 has adhesive properties. As described above, the adhesive layer 12 of the inner bag film 1 preferably has heat fusion properties. In addition, the adhesive layers 12 preferably have heat fusion properties with each other. In addition, as described above, the adhesive layer 12 of the inner bag film 1 preferably has adhesive properties to metal.

[0052] The resin contained in the adhesive layer 12 is not particularly limited as long as it has adhesiveness. Examples of the resin contained in the adhesive layer 12 include resins such as polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, and thermoplastic resins such as modified products of these resins. Among these, polypropylene, ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), and the like are preferable. Specific examples of polyolefin include those exemplified for the substrate 11. The resin contained in the adhesive layer 12 may be only one type, or may be two or more types.

[0053] The resin contained in the adhesive layer 12 preferably has excellent CO2 permeability. The adhesive layer 12 preferably has a CO2 permeability of about 100,000 cc / m2 at a temperature of 23°C and a relative humidity of 0% for 24 hours. 2 More preferably, about 120,000 cc / m 2 More preferably, about 150,000 cc / m 2 The upper limit of the CO2 permeability is, for example, about 400,000cc / m 2 and more preferably about 300,000 cc / m 2 The preferred range of the CO2 permeability is 100,000 to 400,000 cc / m 2 degree, 100,000~300,000cc / m 2 degree, 120,000~400,000cc / m 2 degree, 120,000~300,000cc / m 2 degree, 150,0000~400,000cc / m 2 Degree, 150,000~300,000cc / m 2 The degree of

[0054] From the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the thickness of adhesive layer 12 is preferably 2 μm or more, more preferably 3 μm or more, and even more preferably 4 μm or more, and is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. Preferred ranges include about 2 to 20 μm, about 2 to 10 μm, about 2 to 8 μm, about 3 to 20 μm, about 3 to 10 μm, about 3 to 8 μm, about 4 to 20 μm, about 4 to 10 μm, and about 4 to 8 μm.

[0055] (Method of manufacturing inner bag film for semi-solid batteries) The manufacturing method of the inner bag film 1 is not particularly limited as long as an inner bag film for a semi-solid battery can be obtained, and known or commonly used film-forming methods and lamination methods can be applied. The inner bag film 1 can be manufactured by known film-forming methods and / or lamination methods such as extrusion or co-extrusion, cast molding, T-die method, cutting method, inflation method, etc. For example, the films constituting each layer prepared in advance may be laminated via an adhesive, a molten resin composition may be laminated on a layer prepared in advance by extrusion or co-extrusion, a plurality of layers may be simultaneously prepared and laminated by melt pressure bonding, or one or more types of resins may be applied and dried to coat another layer.

[0056] In addition, in order to improve the adhesiveness of each layer constituting the inner bag film 1, a desired surface treatment can be applied in advance as necessary. For example, a corona-treated layer, an ozone-treated layer, a plasma-treated layer, an oxidation-treated layer, etc. can be formed by optionally performing pretreatment such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, etc. Alternatively, various coating layers such as a primer coating layer, an undercoat coating layer, an anchor coating layer, an adhesive layer, and a vapor deposition anchor coating layer can be optionally formed on the surface to form a surface treatment layer. For the various coating layers, for example, a resin composition containing an isocyanate-based resin, a polyester-based resin, a polyamide-based resin, a polyurethane-based resin, an epoxy-based resin, a phenol-based resin, a (meth)acrylic resin, a polyvinyl acetate-based resin, a polyolefin-based resin such as polyethylene or polypropylene, or a copolymer or modified resin thereof, a cellulose-based resin, etc. as a vehicle as a main component can be used.

[0057] Each layer constituting the inner bag film for a semi-solid battery can be further uniaxially or biaxially stretched by a conventionally known method using a tenter system, a tubular system or the like, as necessary.

[0058] 2. Semi-solid battery In the semi-solid battery 10 of the present disclosure, a battery element 4 including at least a semi-solid positive electrode, a semi-solid negative electrode, and an electrolyte is housed in an inner bag formed by an inner bag film 1 for a semi-solid battery, and the inner bag is further housed in a package formed by an exterior material 3. As described above, the inner bag film 1 is composed of a laminate including at least a substrate 11 and an adhesive layer 12, and the substrate 11 contains polyolefin.

[0059] As described above, in the semi-solid battery 10 of the present disclosure, the battery element 4 is covered by the inner bag film 1, which is further covered by the exterior material 3. More specifically, in the semi-solid battery 10 of the present disclosure, the battery element 4 is housed in an inner bag formed by the inner bag film 1, and further, a plurality of inner bags housing the battery element 4 are housed in a package formed by the exterior material 3. The battery element 4 preferably has a structure sealed (sealed) by the inner bag film 1. In addition, the battery element 4 and the inner bag film 1 preferably have a structure sealed (sealed) by the exterior material 3. The battery element 4 preferably has a structure doubly sealed by the inner bag film 1 and the exterior material 3.

[0060] The battery element 4 can be sealed in the inner bag by covering the battery element 4 with the inner bag film 1 and heat-sealing the flange portion of the inner bag film 1. Furthermore, the inner bag with the battery element 4 sealed therein can be covered with an exterior material 3 and heat-sealed the flange portion of the inner bag film 1 to seal the battery element in the inner bag. The inner bag film 1 is used with the adhesive layer 12 facing inside (the surface in contact with the battery element 4).

[0061] The semi-solid battery 10 may be a package in which a plurality of inner bags each containing a battery element 4 are housed. In this case, at least a portion of the inner bags each containing a battery element 4 can be fixed together by heat fusion. Specifically, at least two inner bags can be fixed together by heat fusion of the base materials 11 of the inner bag film 1 constituting the inner bag. The position where the packages are heat fused together is not particularly limited, but the peripheral portion 30a of the inner bag is preferable. In addition, it is not essential to heat fusion all the inner bags contained in the package, but from the viewpoint of sufficiently fixing the inner bags, it is preferable to heat fusion all the adjacent inner bags together.

[0062] For example, as shown in FIG. 3, in the semi-solid battery 10 of the present disclosure, the battery element 4 is covered with the inner bag film 1 to form each cell 30. Furthermore, the multiple cells 30 are covered with the exterior material 3. For example, in FIG. 3, the inner bag (cell 30) containing the battery element 4 is covered with the exterior material 3 so that a flange portion (peripheral portion 3a of the exterior material 3) of the exterior material 3 is formed near the periphery of the inner bag (cell 30) containing the battery element 4, and the flange portion of the exterior material 3 is heat-sealed to form a package containing the inner bag (cell 30). In this way, in the present disclosure, the inner bag containing the battery element 4 can be the cell 30. Note that the use of the inner bag film 1 of the present disclosure is not limited to the inner bag of the cell (single cell), and there is no particular limit to the use of the inner bag film 1 as long as it is disposed between the exterior material 3 and the battery element 4 of the semi-solid battery 10.

[0063] In the semi-solid battery 10 shown in the schematic diagram of Fig. 3, two cells 30 are housed in a package formed by an exterior material 3, and in each cell 30, a battery element 4 is housed in an inner bag formed by an inner bag film 1. When the semi-solid battery 10 is made into a module, the number of cells in the package may be two or more, and for example, 2 to 20 cells are housed in the package.

[0064] 3, each inner bag is composed of two inner bag films 1. In each cell 30, the adhesive layers 12 of the two inner bag films 1 are bonded together at the flange portions 30a to seal the battery element 4 in the inner bag. The inner bag may be composed of one inner bag film, or two or more inner bag films. When making an inner bag from a single inner bag film, the inner bag film 1 is folded in half and the battery element 4 is sandwiched between and sealed.

[0065] In FIG. 3, the cells 30 are fixed together by heat sealing the base material 11 of the inner bag film 1 that constitutes the outer surface of the inner bag at the flange portion of the inner bag (the peripheral portion 30a of the inner bag).

[0066] The inner bag film 1 is used with the above-mentioned adhesive layer 12 facing inside (the surface in contact with the battery element 4). The exterior material 3 is used with the below-mentioned heat-sealable resin layer 35 facing inside (the surface in contact with the inner bag film 1).

[0067] As shown in Fig. 3, the metal terminal 2 protrudes outside the exterior material 3. The metal terminal 2 is connected to each of the positive and negative electrodes of the battery element 4. Fig. 3 shows a schematic diagram of an electrode 40 connected from the battery element 4 to the metal terminal 2. An adhesive film 21 for a metal terminal can be disposed between the metal terminal 2 and the exterior material 3. By disposing the adhesive film 21 for a metal terminal, the adhesion between the metal terminal 2 and the heat-sealable resin layer 35 of the exterior material 3 can be improved.

[0068] As shown in Fig. 3, in the semi-solid battery 10, the inner bag film 1 (the adhesive layer 12) can be adhered to the electrode 40 at positions where the electrode 40 is present, and the inner bag films 1 (the adhesive layers 12) can be adhered to each other at positions where the electrode 40 is not present. In order to adhere the inner bag film 1 to the electrode 40, it is preferable that the adhesive layer 12 has adhesiveness to metal. Also, in the semi-solid battery 10, in positions where the metal terminal 2 is present, the exterior material 3 (the heat-sealable resin layer 35) can be adhered to the metal terminal 2 via the adhesive film 21 for metal terminal, and in positions where the metal terminal 2 is not present, the exterior materials 3 (the heat-sealable resin layer 35) can be adhered to each other.

[0069] Although not shown in the figures, in the semi-solid battery 10, the end of the inner bag film 1 (at least a part of the peripheral portion 30a (flange portion) of the inner bag) may be located at the flange portion (peripheral portion 3a of the outer bag 3) of the outer bag 3. Specifically, that is, the inner bag may be arranged so that the end of the inner bag film 1 is present at at least a part of the position where the heat-sealable resin layers 35 of the outer bag 3 are heat-sealed to each other and / or at least a part of the position where the heat-sealable resin layer 35 of the outer bag 3 is adhered to the metal terminal 2. By arranging in this way, it is possible to heat-seal the base material 11 of the inner bag film 1 and the heat-sealable resin layer 35 of the outer bag 3 to fix the inner bag more firmly. In addition, the upper surface portion, the lower surface portion, etc. of the inner bag may be heat-sealed to the thermoplastic resin 35 of the outer bag 3. In this way, the inner bag and the outer bag can be fixed, and there is no need to form a flange portion on the inner bag, and the effect of miniaturizing (saving space) the semi-solid battery 10 is also achieved.

[0070] The semi-solid battery to which the inner bag film 1 of the present disclosure is applied is not particularly limited. In the semi-solid battery, the positive electrode and the negative electrode are electrochemically active semi-solids. The positive electrode and the negative electrode may have, for example, an active material and an electrolyte. The electrolyte may be, for example, a solvent or a solvent mixture to which a salt is added. The positive electrode and the negative electrode may include an additive. The positive electrode and the negative electrode may include, for example, the active materials, compositions, and semi-solid suspensions described in U.S. Provisional Patent Application No. 61 / 787,382 entitled "Semi-Solid Electrodes Having High Rate Capability" and U.S. Provisional Patent Application No. 61 / 787,372 entitled "Asymmetric Battery Having a Semi-Solid Cathode and High Energy Density Anode".

[0071] The thickness of each of the positive electrode and the negative electrode can be, for example, about 250 to 2000 μm.

[0072] In a semi-solid battery, a separator is located between the positive and negative electrodes and separates the positive and negative sides of the battery element. The separator reduces the possibility of short circuits within the battery element. The separator comprises an insulator. The separator may comprise, for example, a ductile and elastic polymer. The separator may comprise, for example, a polyolefin, polyvinyl chloride, nylon, fluorocarbon, or polystyrene.

[0073] [Exterior material 3] In the present disclosure, for example, a metal can can be used as the exterior material 3. On the other hand, as described above, as an exterior material 3 capable of realizing a reduction in thickness and weight, an exterior material having a laminated structure consisting of at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 35 in this order is also suitable. FIG. 2 shows an example of a cross-sectional structure of such an exterior material 3, in which a base material layer 31, an adhesive layer 32 provided as needed, a barrier layer 33, an adhesive layer 34 provided as needed, and a heat-sealable resin layer 35 are laminated in this order. In the exterior material 3, the base material layer 31 is the outer layer side, and the heat-sealable resin layer 35 is the innermost layer. When assembling a semi-solid battery, the heat-sealable resin layers 35 located on the periphery of the battery element 4 are brought into contact with each other and heat-sealed to seal the battery element 4, thereby sealing the battery element 4. 3 illustrates the semi-solid battery 10 using an embossed exterior material 3 formed by embossing or the like, but the exterior material 3 may be an unformed pouch type. The pouch type includes three-sided seal, four-sided seal, pillow type, and the like, and any type may be used.

[0074] The thickness of the laminate constituting the exterior material 3 is not particularly limited, but from the viewpoint of cost reduction, energy density improvement, etc., examples of the thickness include about 210 μm or less, preferably about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. Moreover, from the viewpoint of maintaining the function of the exterior material for a semisolid battery, which is to protect the battery element, the thickness of the laminate constituting the semisolid battery is preferably about 35 μm or more, about 45 μm or more, and about 60 μm or more. Preferred ranges for the laminate constituting the semisolid battery exterior material 3 include, for example, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm. In particular, when making the semisolid battery lighter and thinner, about 60 to 155 μm is preferred, and when improving formability, about 155 to 190 μm is preferred.

[0075] (Base material layer 31) In the packaging material 3, the base material layer 31 is a layer that functions as a base material of the packaging material, and is a layer that forms the outermost layer side.

[0076] The material for forming the base layer 31 is not particularly limited, as long as it has insulating properties. Examples of materials for forming the base layer 31 include polyester, polyamide, epoxy, acrylic resin, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, and mixtures and copolymers thereof. Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantage of being excellent in electrolyte resistance and being unlikely to cause whitening due to adhesion of electrolyte, and are preferably used as materials for forming the base layer 31. In addition, polyamide films have excellent stretchability and can prevent whitening due to resin cracking of the base layer 31 during molding, and are preferably used as materials for forming the base layer 31.

[0077] The base layer 31 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film, is preferably used as the base layer 31 because its heat resistance is improved by oriented crystallization.

[0078] Among these, the resin film forming the base layer 31 is preferably nylon or polyester, and more preferably biaxially oriented nylon or biaxially oriented polyester.

[0079] The base layer 31 may be laminated with resin films of different materials in order to improve pinhole resistance and insulation when used as a package for a semi-solid battery. Specifically, a multi-layer structure in which a polyester film and a nylon film are laminated, a multi-layer structure in which a biaxially oriented polyester and a biaxially oriented nylon are laminated, and the like may be mentioned. When the base layer 31 has a multi-layer structure, each resin film may be bonded via an adhesive, or may be directly laminated without an adhesive. When bonding without an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal lamination method may be mentioned.

[0080] The base layer 31 may be made to have low friction in order to improve formability. When making the base layer 31 low-friction, the coefficient of friction of the surface is not particularly limited, but may be, for example, 1.0 or less. To make the base layer 31 low-friction, for example, matte treatment, formation of a thin film layer of a slip agent, a combination of these, etc. may be used.

[0081] The thickness of the base layer 31 is, for example, about 10 to 50 μm, and preferably about 15 to 30 μm.

[0082] (Adhesive layer 32) In the packaging material 3, the adhesive layer 32 is a layer that is disposed on the base material layer 31 as necessary in order to impart adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.

[0083] The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-component curing adhesive or a one-component curing adhesive. The adhesion mechanism of the adhesive used to form the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a thermal melting type, a thermal pressure type, and the like.

[0084] The resin component of the adhesive that can be used to form the adhesive layer 32 is preferably a polyurethane-based two-component curing adhesive; or a blend resin of polyamide, polyester, or these with modified polyolefin, from the viewpoint of having excellent ductility, durability under high humidity conditions, yellowing prevention, and thermal degradation prevention during heat sealing, and of effectively suppressing a decrease in the laminate strength between the base layer 31 and the barrier layer 33 and preventing the occurrence of delamination.

[0085] The adhesive layer 32 may be multi-layered with different adhesive components. When the adhesive layer 32 is multi-layered with different adhesive components, it is preferable to select a resin having excellent adhesion to the base material layer 31 as the adhesive component arranged on the base material layer 31 side, and an adhesive component having excellent adhesion to the barrier layer 33 as the adhesive component arranged on the barrier layer 33 side, from the viewpoint of improving the laminate strength between the base material layer 31 and the barrier layer 33. When the adhesive layer 32 is multi-layered with different adhesive components, specifically, the adhesive component arranged on the barrier layer 33 side is preferably an acid-modified polyolefin, a metal-modified polyolefin, a mixed resin of polyester and acid-modified polyolefin, a resin containing a copolymerized polyester, or the like.

[0086] The thickness of the adhesive layer 32 is, for example, about 2 to 50 μm, and preferably about 3 to 25 μm.

[0087] (Barrier layer 33) In the exterior material 3, the barrier layer 33 is a layer that has the function of preventing water vapor, oxygen, light, and the like from penetrating into the inside of the semi-solid battery in addition to improving the strength of the exterior material. The barrier layer 33 is preferably a metal layer, that is, a layer formed of a metal. Specific examples of metals constituting the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer 33 can be formed, for example, of a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with these vapor deposition films, and is preferably formed of a metal foil, and more preferably formed of an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 33 during the production of the exterior material, it is more preferable that the barrier layer be formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0088] The thickness of the barrier layer 33 is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, or about 65 to 85 μm, from the viewpoint of making the exterior material thin while making it difficult for pinholes to occur during molding.

[0089] Moreover, it is preferable that at least one surface, and preferably both surfaces, of the barrier layer 33 are subjected to a chemical conversion treatment in order to stabilize adhesion, prevent dissolution or corrosion, etc. Here, the chemical conversion treatment refers to a treatment for forming a corrosion-resistant film on the surface of the barrier layer.

[0090] (adhesive layer 34) In the exterior packaging material 3, the adhesive layer 34 is a layer that is provided, if necessary, between the barrier layer 33 and the heat-sealable resin layer 35 in order to firmly bond the heat-sealable resin layer 35.

[0091] The adhesive layer 34 is formed by an adhesive capable of adhering the barrier layer 33 and the heat-sealable resin layer 35. The composition of the adhesive used to form the adhesive layer is not particularly limited, and examples thereof include a resin composition containing an acid-modified polyolefin. The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the polyolefin to be modified with acid include the above-mentioned polyolefins, copolymers obtained by copolymerizing the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for the acid modification include carboxylic acids or anhydrides thereof such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin with an acid component, or by block polymerization or graft polymerization of an acid component to the cyclic polyolefin. The acid-modified cyclic polyolefin is the same as described above. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin described above.

[0092] Preferred acid-modified polyolefins include polyolefins modified with a carboxylic acid or anhydride thereof, polypropylenes modified with a carboxylic acid or anhydride thereof, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0093] The thickness of the adhesive layer 34 is, for example, about 1 to 40 μm, and preferably about 2 to 30 μm.

[0094] (Thermal adhesive resin layer 35) In the exterior packaging material 3, the heat-sealable resin layer 35 corresponds to the innermost layer, and is a layer that seals the battery element by heat-sealing the heat-sealable resin layers together when assembling the semi-solid battery.

[0095] The resin component used in the heat-sealable resin layer 35 is not particularly limited as long as it is heat-sealable, and examples thereof include polyolefin and cyclic polyolefin. By forming the heat-sealable resin layer 35 from polyolefin, good adhesion is achieved when the inner bag film 1 and the exterior material 3 are heat-sealed.

[0096] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferable.

[0097] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, preferred are cyclic alkenes, and more preferred are norbornene. Another example of the constituting monomer is styrene.

[0098] Among these resin components, preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blend polymers thereof; more preferred are polyethylene, polypropylene, copolymers of ethylene and norbornene, and blend polymers of two or more of these.

[0099] The heat-sealable resin layer 35 may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components. The heat-sealable resin layer 35 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. It is particularly preferable that the adhesive layer 12 of the inner bag film 1 and the heat-sealable resin layer 35 are made of the same resin, since this improves the adhesion between these layers.

[0100] The thickness of the heat-sealable resin layer 35 is not particularly limited, but may be about 2 to 2000 μm, preferably about 5 to 1000 μm, and more preferably about 10 to 500 μm. The thickness of the heat-sealable resin layer 35 may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 34 is 10 μm or more, the thickness of the heat-sealable resin layer 35 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 34 is less than 10 μm or when the adhesive layer 34 is not provided, the thickness of the heat-sealable resin layer 35 is preferably about 20 μm or more, and more preferably about 35 to 85 μm. EXAMPLES

[0101] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0102] <Manufacturing of inner bag films for semi-solid batteries> (Examples 1 and 2) A two-layered inner bag film (total thickness 20 μm) for semi-solid batteries was manufactured by extrusion molding polypropylene (PP) or ethylene-methacrylic acid copolymer (EMAA) as an adhesive layer (thickness 4 μm) on one side of oriented polypropylene film (OPP) as a substrate (thickness 16 μm) so as to obtain the laminated structure shown in Table 1. The CO2 permeability of the substrate shown in Table 1 is the CO2 permeability at a temperature of 25°C and a relative humidity of 65% RH for 24 hours, and is the value described in "For Functional Food Packaging Materials, Ishikawa Kosuke, CMC Publishing Co., Ltd., Publication Date: April 2005, p. 73."

[0103] Comparative Example 1 A two-layered inner bag film for semi-solid batteries (total thickness 20 μm) was manufactured by extrusion molding an ethylene-methacrylic acid copolymer (EMAA) as an adhesive layer (thickness 8 μm) on a polyethylene terephthalate film as a substrate (thickness 12 μm) so as to obtain the laminated structure shown in Table 1. The CO2 permeability of the substrate shown in Table 1 is the CO2 permeability at a temperature of 25°C and a relative humidity of 65% RH for 24 hours, and is the value described in "For Functional Food Packaging Materials, Ishikawa Kosuke, CMC Publishing Co., Ltd., Publication Date: April 2005, p. 73."

[0104] <Evaluation of heat fusion properties of inner film for semi-solid batteries> The heat fusion property between the substrates of the inner bag film for semi-solid batteries was evaluated by the following method. The results are shown in Table 1. The substrates of the inner bag film for semi-solid batteries were heat fused together, and the peel strength in a 25°C environment was measured as follows. A sample was cut out from the inner bag film for semi-solid batteries into a strip shape with a length of 80 mm in the MD direction and a width of 15 mm in the TD direction. The sample was folded in the MD direction with the substrate side facing inward, and heated and pressed with a heat sealer (width of heat seal bar: 7 mm) to prepare a measurement sample (length in the MD direction: 40 mm). Next, the measurement sample was attached to a tensile tester, and the peel strength between the substrates was measured under conditions of a tensile speed of 50 mm / min and a gauge length of 50 mm, and the maximum strength (N / 15 mm) at the time of peeling was adopted. It was taken as the average value of three measurements. The heat seal conditions were fixed at a temperature of 170°C, a surface pressure of 0.4 MPa, and a press time of 0.3 seconds. The sealability evaluation criteria are as follows. A+: The peel strength between the substrates exceeded 1.0 N / 15 mm. A: The peel strength between the substrates was 0.1 N / 15 mm or more and 1.0 N / 15 mm or less. C: The peel strength between the substrates was less than 0.1 N / 15 mm, or the substrates were not thermally fused to each other.

[0105] <Moldability evaluation> The formability of the inner bag film for semi-solid batteries was evaluated by the following method. The results are shown in Table 1. The inner bag film for semi-solid batteries was cut into a rectangle with a length (MD direction) of 90 mm and a width (TD direction) of 150 mm to prepare a test sample. This sample was placed in a 25°C environment in a rectangular molding die (female die, the surface has a maximum height roughness (nominal value of Rz) of 3.2μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0mm, ridge R1.0mm) with an aperture of 31.6mm (MD) x 54.5mm (TD) and a corresponding molding die (male die, the surface of the ridgeline has a maximum height roughness (nominal value of Rz) of 1.6μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0mm, ridge R1.0mm). The maximum height roughness (nominal value of Rz) specified in Table 2 of the surface roughness standard piece for comparison is 3.2 μm. Using a corner R2.0 mm, ridge R1.0 mm), the pressing pressure (surface pressure) was 0.25 MPa, and the molding depth was changed in 0.5 mm increments from a molding depth of 0.5 mm, and cold molding (one-stage drawing molding) was performed on 10 samples each. At this time, the above test sample was placed on the female mold so that the heat-sealable resin layer side was located on the male mold side, and molding was performed. In addition, the clearance between the male mold and the female mold was 0.3 mm. The samples after cold molding were irradiated with light from a penlight in a dark room to confirm whether pinholes or cracks were generated in the inner bag film for semi-solid batteries due to the transmission of light. The deepest molding depth at which no pinholes or cracks occurred in the inner bag film for semi-solid batteries among all 10 samples was defined as A mm, and the number of samples at which pinholes, etc. occurred in the inner bag film for semi-solid batteries at the shallowest molding depth was defined as B. The value calculated by the following formula was rounded off to two decimal places to determine the limit molding depth of the inner bag film for semi-solid batteries. Limit forming depth = A mm + (0.5 mm / 10 pieces) x (10 pieces - B pieces)

[0106] <Heat resistance evaluation> The heat resistance of the inner bag film for semi-solid batteries was evaluated by the following method. The results are shown in Table 1. The peel strength in an 80°C environment was measured as follows. A sample was cut out from the inner bag film for semi-solid batteries in a strip shape with a width of 15 mm in the TD direction, folded with the adhesive layer side facing inward, and bonded with a heat sealer (heat seal bar width 7 mm) to prepare a measurement sample. Next, the measurement sample was attached to a tensile tester, and the adhesive strength (peel strength) between the adhesive layers was measured under conditions of a tensile speed of 50 mm / min and a gauge length of 50 mm, and the maximum strength (N / 15 mm) at the time of peeling was adopted. It was the average value of three measurements. The heat seal conditions were fixed at a temperature of 150°C, a surface pressure of 0.4 MPa, and a press time of 0.3 seconds, and the measurement was performed. The heat resistance evaluation criteria are as follows. A: Peel strength is 1.0 (N / 15mm) or more B: Peel strength is less than 1.0 (N / 15mm)

[0107] [Table 1]

[0108] As described above, the present disclosure provides the following aspects of the invention. Item 1. An inner bag film for a semi-solid battery, which is disposed between an exterior material of the semi-solid battery and a battery element, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The inner bag film for a semi-solid battery, wherein the substrate comprises a polyolefin. Item 2. The inner bag film for a semi-solid battery according to Item 1, wherein the substrate is made of a stretched polypropylene film. Item 3. The inner bag film for a semisolid battery according to Item 1 or 2, wherein the adhesive layer has adhesiveness to metal. Item 4. The inner bag film for a semisolid battery according to any one of Items 1 to 3, wherein the substrate has a thickness of 5 μm or more and 30 μm or less. Item 5. The inner bag film for a semisolid battery according to any one of Items 1 to 4, wherein the adhesive layer has a thickness of 2 μm or more and 20 μm or less. Item 6. The inner bag film for a semisolid battery according to any one of Items 1 to 5, wherein the inner bag film for a semisolid battery does not have a metal layer formed of a metal. Item 7. The substrate has a CO2 permeability of 6000cc / m2 at a temperature of 23°C and a relative humidity of 0% RH for 24 hours. 2 Item 7. The inner bag film for a semisolid battery according to any one of items 1 to 6, which is as described above. Item 8. The inner bag film for a semisolid battery according to any one of Items 1 to 7, wherein the exterior material is composed of a laminate in which at least a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order. Item 9. The inner bag film for a semisolid battery according to any one of Items 1 to 8, wherein the inner bag film has no holes for allowing gas to pass therethrough. Item 10. A semi-solid battery in which a battery element having at least a semi-solid positive electrode, a semi-solid negative electrode, and an electrolyte is housed in an inner bag formed of an inner bag film for semi-solid batteries, and the inner bag is housed in a package formed of an exterior material, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The substrate comprises a polyolefin. Item 11. The semi-solid battery according to item 10, wherein a plurality of the inner bags each containing the battery element are contained in the packaging body. Item 12. The semi-solid battery according to item 11, wherein at least some of the inner bags housing the battery elements are fixed to each other by thermal fusion. [Explanation of symbols]

[0109] 1. Inner bag film for semi-solid batteries 2 metal terminals 3 Exterior materials 3a Periphery of exterior material 4 Battery elements 10 Semi-solid battery 11 Base material 12 Adhesive layer 21 Adhesive film for metal terminals 30 cells 30a Periphery of inner bag 31 Base material layer 32 Adhesive layer 33 Barrier Layer 34 Adhesive layer 35 Heat-fusible resin layer 40 electrodes

Claims

1. An inner bag film for a semi-solid battery, which is disposed between an exterior material of the semi-solid battery and a battery element, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The substrate comprises a polyolefin, The inner bag film for a semi-solid battery does not have a metal layer formed of a metal.

2. The inner bag film for a semi-solid battery according to claim 1 , wherein the substrate is made of a stretched polypropylene film.

3. The inner bag film for a semi-solid battery according to claim 1 or 2, wherein the adhesive layer has adhesiveness to metal.

4. The inner bag film for a semi-solid battery according to claim 1 or 2, wherein the substrate has a thickness of 5 μm or more and 30 μm or less.

5. The inner bag film for a semi-solid battery according to claim 1 or 2, wherein the adhesive layer has a thickness of 2 μm or more and 20 μm or less.

6. The substrate was subjected to CO 2 Permeability: 6000cc / m 2 The inner bag film for a semi-solid battery according to claim 1 or 2.

7. 3. The inner bag film for a semi-solid battery according to claim 1, wherein the exterior material is composed of a laminate in which at least a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order.

8. The inner bag film for a semi-solid battery according to claim 1 or 2, wherein the inner bag film has no holes for allowing gas to pass therethrough.

9. A semi-solid battery, comprising: a battery element including at least a semi-solid positive electrode, a semi-solid negative electrode, and an electrolyte; an inner bag formed of an inner bag film for a semi-solid battery; and the inner bag is further housed in a package formed of an exterior material, The inner bag film for a semi-solid battery is composed of a laminate including at least a substrate and an adhesive layer, The substrate comprises a polyolefin, The inner bag film for a semi-solid battery does not have a metal layer formed of a metal.

10. The semi-solid battery according to claim 9 , wherein a plurality of the inner bags each containing the battery element are contained in the packaging body.

11. The semi-solid battery according to claim 10 , wherein at least some of the inner bags housing the battery elements are fixed to each other by thermal fusion.

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