Battery pack, manufacturing method of the battery pack, and manufacturing method of recycling molding

Abstract

To provide a battery pack capable of performing a material recycling.SOLUTION: A battery pack 20 includes: an upper case main body 23; an upper case 22 that includes an upper flange 24 that is projected toward an outside along a horizontal surface from an outer peripheral edge of an upper case main body, is formed by a material containing a synthetic resin; a lower case 42 that is projected toward an outside along the horizontal surface from the outer peripheral edge of a lower case main body 43 and the lower case main body, and includes a lower flange 44 that is arranged so as to be opposite from a lower direction to the upper flange; and a power storage part 51 that is arranged to a housing space S1 to be formed by the upper case main body and the lower case main body. The battery pack further includes a thermoplastic elastomer layer 61 that is formed by a composition containing a rubber single and / or a rubber, and a thermoplastic resin to between the upper flange and the lower flange.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a battery pack, a method for manufacturing a battery pack, and a method for manufacturing a recycled molded product.

Background Art

[0002] Conventionally, a battery pack in which a power storage unit is disposed in a case has been known (see, for example, Patent Documents 1 and 2).

[0003] The case includes an upper case and a lower case. The upper case has an upper case body formed in a toped cylindrical shape and an upper flange protruding outward from the outer peripheral edge of the lower end portion of the upper case body. The lower case has a lower case body formed in a bottomed cylindrical shape and a lower flange protruding outward from the outer peripheral edge of the upper end portion of the lower case body. The upper flange of the upper case is disposed so as to face the lower flange of the lower case. A predetermined power is stored in the power storage unit. The power storage unit is disposed in the upper case body and the lower case body.

[0004] A sealing material is used between the upper flange and the lower flange (see, for example, Patent Document 1).

[0005] In recent years, as part of environmental measures, research and development of electric vehicles and hybrid vehicles have been promoted, and development and weight reduction of high energy density batteries aiming at improving the cruising range have been actively carried out. Such high energy density batteries may catch fire due to an accidental accident, and since the case requires high flame retardancy as a safety measure for passengers, a metal material and a refractory material are often used in combination. However, metal materials have the drawback of being heavy, and when used in combination with refractory materials, cost increases due to workability and an increase in the number of parts become issues. Therefore, resinification that has the potential to achieve both weight reduction and flame shielding properties has been attempted (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Currently, towards a sustainable society, suppression of carbon dioxide and recyclability have been emphasized. However, the vulcanized rubber conventionally used as a sealing material has problems such as being difficult to recycle materials.

[0008] Therefore, the present invention has been made in view of such problems, and an object thereof is to provide a battery pack capable of material recycling.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention proposes the following means. (1)Aspect 1 of the present invention is a battery pack comprising an upper case having an upper case body and an upper flange protruding outward along a horizontal plane from an outer peripheral edge of the upper case body and formed of a material containing a synthetic resin, a lower case having a lower case body and a lower flange protruding outward along a horizontal plane from an outer peripheral edge of the lower case body and arranged to face the upper flange from below, and a power storage unit arranged in an accommodation section formed by the upper case body and the lower case body, and having a thermoplastic elastomer layer formed between the upper flange and the lower flange by a rubber alone and / or a composition containing rubber and a thermoplastic resin.

[0010] (2)Aspect 2 of the present invention may be the battery pack according to (1), wherein the thermoplastic elastomer layer is formed of a material containing either or both of an olefin rubber and a polyolefin resin. (3)Aspect 3 of the present invention may be the battery pack according to (1) or (2), wherein the synthetic resin contains a thermoplastic resin. (4)Aspect 4 of the present invention may be the battery pack according to any one of (1) to (3), wherein the synthetic resin contains a polyolefin resin. (5)Aspect 5 of the present invention may be the battery pack according to any one of (1) to (4), wherein the upper case is formed of a resin fiber composite material in which fibers are mixed with a synthetic resin. (6)Aspect 6 of the present invention may be the battery pack according to (5), wherein the fibers contain glass fibers. (7)Aspect 7 of the present invention may be the battery pack according to (5) or (6), wherein the resin fiber composite material is a stampable sheet. (8)Aspect 8 of the present invention may be the battery pack according to any one of (1) to (7), wherein the thermoplastic elastomer layer is in direct contact with at least one of the upper flange and the lower flange. (9)Aspect 9 of the present invention may be the battery pack according to any one of (1) to (8), which has a convex portion protruding upward from the upper flange. (10)Aspect 10 of the present invention may be a method for manufacturing the battery pack according to any one of (1) to (9), wherein the thermoplastic elastomer layer is heat-sealed to at least one of the upper flange and the lower flange. (11)Aspect 11 of the present invention may be a method for manufacturing the battery pack according to any one of (1) to (9), wherein the thermoplastic elastomer layer is formed by a three-dimensional laminated molding method. (12)Aspect 12 of the present invention may be a method for manufacturing a recycled molded product, which includes a recovery step of recovering the upper case and the thermoplastic elastomer layer from the battery pack according to any one of (1) to (9), a pulverization step of pulverizing the recovered material by the recovery step, and a manufacturing step of manufacturing a recycled molded product containing the pulverized material by the pulverization step as a raw material.

Advantages of the Invention

[0011] In the battery pack of the present invention, material recycling is possible.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] Hereinafter, an electric vehicle using an embodiment of the battery pack according to the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, this electric vehicle 1 includes a chassis 10, tires 15, and the battery pack 20 of this embodiment. For example, the chassis 10 of this embodiment constitutes a part of the skeleton of the electric vehicle 1. The chassis 10 extends along a horizontal plane. Here, when it is said that A is along B, it means that the angle formed by A and B is 30 degrees or less. It is more preferable that this formed angle is 15 degrees or less. For example, A corresponds to the chassis 10 and B corresponds to the horizontal plane. The chassis 10 supports a motor (not shown). An opening 10a penetrating in the vertical direction is formed in the chassis 10. A plurality of through holes (reference numerals omitted) penetrating in the vertical direction are formed at the peripheral edge of the opening 10a in the chassis 10.

[0014] The battery pack 20 is supported by the chassis 10. Electric power is stored in the battery pack 20. The battery pack 20 supplies the stored electric power to the motor based on an instruction from the operator of the electric vehicle 1. Details of the battery pack 20 will be described later. The tires 15 are rotatably supported by the chassis 10 via a suspension (not shown). The motor rotates the tires 15 in a predetermined direction.

[0015] As shown in FIG. 1, the battery pack 20 includes a case 21, a power storage unit 51, and a fixing unit 56. The case 21 has an upper case 22 and a lower case 42. The upper case 22 has an upper case body 23 and an upper flange 24. The upper case body 23 is formed in a top-covered cylindrical shape. That is, the upper case body 23 has an upper side wall 32 and a top wall 33. Therefore, a part of the storage space S1 formed inside the upper side wall 32 can accommodate the power storage unit 51. The upper side wall 32 is formed in a square tube shape (tubular shape) presenting a rectangular edge shape when viewed in the vertical direction. Hereinafter, the direction along one outer edge (short side) of the upper side wall 32 when viewed in the vertical direction is referred to as the first direction X. The first direction X is a direction along the horizontal plane. Hereinafter, the direction orthogonal to the vertical direction and orthogonal to the first direction X is referred to as the second direction Y.

[0016] Note that the shape of the upper side wall 32 is not limited thereto, and may be formed in a tubular shape presenting a triangular, pentagonal or more edge shape, a circular edge shape, etc. when viewed in the vertical direction. The top wall 33 closes an opening formed at the upper end of the upper side wall 32. Hereinafter, the central axis of the top wall 33 is referred to as the axis O1. For example, the axis O1 is an axis passing through the center of gravity of the top wall 33 and extending along the vertical direction.

[0017] The upper flange 24 protrudes from the outer peripheral edge of the lower end of the upper side wall 32 in the upper case body 23 along the horizontal plane toward the outside of the upper side wall 32. The outside mentioned here means the direction away from the axis O1. The upper flange 24 protrudes over the entire circumference of the upper side wall 32. Note that the upper flange 24 may protrude only a part of the circumferential direction of the upper side wall 32 (a part around the axis O1). A plurality of through holes (reference numerals omitted) penetrating in the vertical direction are formed in the upper flange 24. The plurality of through holes are arranged at intervals around the upper side wall 32.

[0018] As shown in FIG. 2, it may have a flange convex portion 25. Since the battery pack 20 has the flange convex portion 25 as a convex portion, it can suppress the flame that wraps around from the outside of the upper flange 24 and burns the outer end of the upper flange 24 from exceeding the flange convex portion 25 and spreading inwardly toward the upper flange 24. The flange convex portion 25 protrudes upward from the upper flange 24. The flange convex portion 25 is arranged on the outer peripheral edge of the upper flange 24. The height of the flange convex portion 25 is about 1 to 2 mm. The flange convex portion 25 presents a rectangular outer peripheral edge shape when viewed from above.

[0019] The upper case body 23, upper flange 24, and flange convex portion 25 of the upper case 22 are integrally formed of a material containing synthetic resin.

[0020] Examples of the resin used for the synthetic resin include thermoplastic resins, thermosetting resins, and elastomer resins. Examples of the thermoplastic resin include polyolefin resins such as polypropylene resin, polyethylene resin, poly(1-)butene resin, and polypentene resin; polyester resins such as polyethylene terephthalate; polystyrene resin; acrylonitrile-butadiene-styrene (ABS) resin; polyvinyl acetal resin; ethylene vinyl acetate copolymer (EVA) resin; polyvinyl alcohol resin; polycarbonate resin; polyphenylene ether resin; acrylic resin; polyamide resin; polyvinyl chloride resin (PVC); novolak resin; polyurethane resin; and polyisobutylene resin. Examples of the thermosetting resin include epoxy resin, vinyl ester resin, urethane resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, and polyimide resin. Examples of the elastomer resin include acrylonitrile butadiene rubber, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, hydrogenated styrene-isoprene block copolymer, and hydrogenated styrene-isoprene-styrene block copolymer. Among them, from the viewpoint of recyclability, it is preferable that the synthetic resin contains a thermoplastic resin, more preferably contains a polyolefin resin, and particularly preferably contains a polypropylene resin. In the present invention, the "polyolefin resin" means a resin in which the proportion of olefin units or cycloolefin units is 90 mol% or more, preferably 95 mol% or more, and more preferably 98 mol% or more, based on 100 mol% of all the constituent units constituting the resin.

[0021] As the material containing the synthetic resin forming the upper case 22, for example, a resin composition imparting flame retardancy to the resin can be used, and a flame-retardant polypropylene resin can be used as the resin composition. For example, the resin composition disclosed in International Publication No. 2021 / 241682 can be preferably used. Specifically, the resin composition contains a thermoplastic resin, a phosphorus-based flame retardant, and a copolymer of an α-olefin and an unsaturated carboxylic acid. The proportion of the phosphorus-based flame retardant with respect to the thermoplastic resin is 5% by mass or more and 400% by mass or less. The proportion of the copolymer with respect to the phosphorus-based flame retardant is 10% by mass or less.

[0022] Also, the upper case 22 may be formed of a resin fiber composite material (fiber-reinforced material) in which fibers are mixed with the synthetic resin. For example, a resin composition containing fibers such as glass fibers or carbon fibers in the synthetic resin may be used, or the synthetic resin may be impregnated with fibers such as glass fibers or carbon fibers. It is preferable that the fibers include glass fibers. As the resin fiber composite material, a stampable sheet is preferable, and a stampable sheet produced by impregnating a mat made of fibers with a synthetic resin is more preferable. For example, the stampable sheet disclosed in International Publication No. 2022 / 220303 can be preferably used. Specifically, the stampable sheet contains a thermoplastic resin, a flame retardant, a dispersant, and inorganic fibers. The content of the inorganic fibers is 1 to 80% by mass based on the total weight. The content of the dispersant with respect to 100 parts by mass of the flame retardant is more than 0 and 25 parts by mass or less.

[0023] As a method for manufacturing the upper case 22, various methods can be used, and from the viewpoint of productivity, press molding is preferable. In press molding, for example, it is preferable to prepare a stampable sheet, stack a plurality of sheets, and perform press molding.

[0024] As shown in FIG. 1, the lower case 42 has a lower case body 43 and a lower flange 44. The lower case body 43 is formed in a bottomed cylindrical shape. That is, the lower case body 43 has a lower side wall 47 and a bottom wall 48. Similar to the upper side wall 32, the lower side wall 47 is formed in a rectangular tubular shape with a rectangular edge when viewed in the vertical direction. The bottom wall 48 closes the opening formed at the lower end of the lower side wall 47.

[0025] The lower flange 44 protrudes outward along the horizontal plane from the outer peripheral edge of the lower side wall 47 of the lower case body 43. The lower flange 44 is arranged to face the upper flange 24 from below the upper flange 24. Here, when it is said that A faces B, it means that A and B face each other with a space therebetween. A plurality of through holes (reference numerals omitted) penetrating in the vertical direction are formed in the lower flange 44. The plurality of through holes are arranged at intervals around the lower side wall 47.

[0026] The lower case 42 (including the lower case body 43 and the lower flange 44) may be integrally formed of the same material as the material containing the synthetic resin forming the upper case 22, or may be formed of iron, aluminum, or the like.

[0027] The thermoplastic elastomer layer 61 is formed of a composition containing rubber alone and / or a rubber and a thermoplastic resin, and is formed between the upper flange 24 and the lower flange 44. That is, there is a thermoplastic elastomer layer 61 between the upper flange 24 and the lower flange 44. An adhesive layer or the like may be provided between the thermoplastic elastomer layer 61 and the upper flange 24, and between the thermoplastic elastomer layer 61 and the lower flange 44. However, from the viewpoints of waterproof and dustproof properties and suppression of an increase in the number of parts, the thermoplastic elastomer layer 61 is preferably in direct contact with at least one of the upper flange 24 and the lower flange 44.

[0028] As the material for forming the thermoplastic elastomer layer, as described above, it may be rubber alone or a composition containing rubber and a thermoplastic resin, and it is preferably a composition containing rubber and a thermoplastic resin. Among them, from the viewpoint of recycling, it is preferable that the material contains either or both of an olefin rubber or a polyolefin resin. By forming the thermoplastic elastomer layer with an elastomer containing either or both of an olefin rubber or a polyolefin resin having excellent recyclability, it is possible to perform melting and reformation by reheating after use and material recycle it as a new product such as a recycled molded product.

[0029] The olefin rubber is preferably a copolymer containing at least two or more α-olefin units. Examples of the α-olefin include ethylene, propylene, 1-butene, 2-methylpropylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like. From the viewpoint of material recycling, it is preferable that ethylene having 2 carbon atoms and propylene having 3 carbon atoms are contained. The α-olefin may be copolymerized with ethylene alone or copolymerized with two or more kinds of ethylene. Further, the olefin rubber may be used alone or in combination of two or more kinds.

[0030] Olefin rubber may have other monomer units such as monomer units based on non-conjugated dienes (non-conjugated diene units) in addition to ethylene units and α-olefin units having 3 to 8 carbon atoms. Examples of the non-conjugated diene include chain non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene; cyclic non-conjugated dienes such as cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene. Preferably, they are 5-ethylidene-2-norbornene and dicyclopentadiene. Further, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, and ethylene-butene copolymers may be partially or completely crosslinked. Among them, from the viewpoints of moldability and rubber elasticity, partial crosslinking is preferred.

[0031] As a method for producing olefin rubber, a known polymerization method using a known catalyst for olefin polymerization is used. For example, as the catalyst for olefin polymerization, a Ziegler-Natta catalyst, a complex catalyst such as a metallocene complex or a non-metallocene complex can be used, and examples of the polymerization method include slurry polymerization method, solution polymerization method, bulk polymerization method, gas phase polymerization method, etc. Also, it is possible to use commercially available corresponding products. Examples of commercially available corresponding products include Engage (registered trademark) series manufactured by Dow Chemical Company, Tafmer (registered trademark) series manufactured by Mitsui Chemicals, Inc., etc.

[0032] As the polyolefin resin, crystalline polyolefin is preferred from the viewpoints of light weight, stable rubber elasticity, excellent mechanical properties, and good moldability. The above crystalline polyolefin may be an unmodified crystalline polyolefin, or may be a modified crystalline polyolefin obtained by modifying a crystalline polyolefin with at least one functional group selected from the group consisting of an acid anhydride group, a carboxyl group, an amino group, an imino group, an alkoxysilyl group, a silanol group, a silyl ether group, a hydroxyl group, and an epoxy group.

[0033] Examples of the crystalline polyolefin include propylene-based polymers, ethylene-based polymers, and the like. These may be used alone or in combination of two or more.

[0034] Examples of the propylene-based polymer include a propylene homopolymer, and a propylene-based copolymer which is a random or block copolymer of polypropylene and an α-olefin such as ethylene, 1-butene, or 1-hexene. The melt flow rate (JIS K 7210, 230 °C, 21.2 N load) of the propylene-based polymer is not particularly limited, but is usually 0.05 to 200 g / 10 min, preferably 0.05 to 100 g / 10 min, and more preferably 0.1 to 80 g / 10 min. By setting the melt flow rate within the above range, the moldability is excellent, the appearance of the resulting thermoplastic elastomer layer is good, and the mechanical properties can be controlled within a desired range.

[0035] It is also possible to use a commercially available product of the propylene-based polymer. Commercially available polypropylene can be procured from manufacturers listed below and can be appropriately selected. Commercially available products that can be obtained include Novatec (registered trademark) PP from Nippon Polypropylene Corporation, Prime Polypro (registered trademark) from Prime Polymer Co., Ltd., Sumitomo Nolen (registered trademark) from Sumitomo Chemical Co., Ltd., polypropylene block copolymer from San Aroma Co., Ltd., Moplen (registered trademark), Circluen from LyondellBasell Industries, ExxonMobil PP from ExxonMobil Corporation, Formolene (registered trademark) from Formosa Plastics Corporation, Borealis PP from Borealis AG, SEETEC PP from LG Chem Ltd., ASI POLYPROPYLENE from A. Schulman, Inc., INEOS PP from INEOS Olefins & Polymers, Braskem PP from Braskem S.A., Sumsung Total from SAMSUNG TOTAL PETROCHEMICALS CO., LTD., Sabic (registered trademark) PP from SABIC, TOTAL PETROCHEMICALS Polypropylene from TOTAL PETROCHEMICALS, YUPLENE (registered trademark) from SK Corporation, and the like.

[0036] Examples of the ethylene polymer include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The density of the ethylene polymer measured according to JIS K 7112 is preferably in the range of 0.910 g / cm 3 to 1.00 g / cm 3 or less from the viewpoint of achieving both mechanical properties and rubber elasticity. The melt flow rate (JIS K 7210, 190 °C, 21.2 N load) of the ethylene polymer is not particularly limited, but is usually 0.05 to 200 g / 10 min, preferably 0.05 to 100 g / 10 min, and more preferably 0.1 to 80 g / 10 min. By setting the melt flow rate within the above range, excellent moldability can be achieved, the appearance of the resulting thermoplastic elastomer layer can be improved, and the mechanical properties can be controlled within a desired range.

[0037] The molecular weights of the above-mentioned propylene-based polymer and ethylene-based polymer are not particularly limited, but preferably include a resin having a weight average molecular weight of 500 to 1,500,000 measured by gel permeation chromatography (GPC). This weight average molecular weight is more preferably 1,000 to 1,000,000, and even more preferably 2,000 to 500,000. The above weight average molecular weight is measured using standard polystyrene as the molecular weight standard substance.

[0038] As described above, the thermoplastic elastomer layer is preferably formed from a material containing either or both of an olefin rubber and a polyolefin resin, more preferably formed from a material containing at least a polyolefin resin, and even more preferably a composition containing an olefin rubber and a polyolefin resin or a composition containing a rubber component other than an olefin rubber and a polyolefin resin. When the thermoplastic elastomer layer is formed from a composition containing a rubber component other than an olefin rubber and a polyolefin resin, it is preferably a composition containing a polyolefin resin and a styrene copolymer rubber as the rubber component other than the olefin rubber.

[0039] The composition containing rubber and a thermoplastic resin may contain a hydrocarbon-based softening agent for rubber from the viewpoints of improving the processability and fluidity of the composition. Examples of the hydrocarbon-based softening agent for rubber include mineral oil-based softening agents and synthetic resin-based softening agents, and mineral oil-based softening agents are particularly preferred. Mineral oil-based softening agents are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Those in which more than 50% of the total carbon atoms are paraffinic hydrocarbons are called paraffin oils, those in which 30 to 45% of the total carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of the total carbon atoms are aromatic hydrocarbons are called aromatic oils. Among these, paraffin oils are preferred.

[0040] The kinematic viscosity at 40°C of the hydrocarbon-based softening agent for rubber is preferably 20 centistokes (cSt) or more, more preferably 50 cSt or more. On the other hand, it is preferably 800 cSt or less, more preferably 600 cSt or less. Further, the flash point (COC method) of the hydrocarbon-based softening agent for rubber is preferably 200°C or more, more preferably 250°C or more.

[0041] Commercially available hydrocarbon-based softening agents for rubber may be used. Examples of commercially available products include the "ENEOS Polybutene (registered trademark) HV" series manufactured by ENEOS, the "Diana (registered trademark) Process Oil PW" series manufactured by Idemitsu Kosan Co., Ltd., and the "VIVA-B-FIX" (registered trademark) series manufactured by H&R.

[0042] The hydrocarbon-based softening agent for rubber can be used alone as only one type, or in any combination and ratio of two or more types.

[0043] Commercially available products can also be used as the composition containing an olefin-based rubber and a polyolefin-based resin. For example, Milastomer (registered trademark) manufactured by Mitsui Chemicals, Inc., the Espolex TPE series (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Thermoran (registered trademark) manufactured by Mitsubishi Chemical Corporation, Trexplane (registered trademark) manufactured by Mitsubishi Chemical Corporation, Tefablock (registered trademark) TPO manufactured by Mitsubishi Chemical Corporation, Santoprene (registered trademark) manufactured by Celanese, Sarlink (registered trademark) manufactured by Toyobo EMS Co., Ltd., Dawnprene (registered trademark) manufactured by Shandong Dawn Polymer, etc.

[0044] As the composition containing styrenic copolymer rubber and polyolefin resin, commercially available products can also be used. For example, Tefabloc (registered trademark) TPS manufactured by Mitsubishi Chemical Corporation, Leostomer (registered trademark) manufactured by Riken Technos Corporation, Elastomer AR (registered trademark) manufactured by Aron Kasei Co., Ltd., Allostomer (registered trademark) manufactured by Aron Kasei Co., Ltd., Ernestone (registered trademark) manufactured by Kuraray Plastics Co., Ltd., THERMOLAST (registered trademark) manufactured by KRAIBURG TPE GMBH & CO.KG, etc. can be mentioned.

[0045] The thermoplastic elastomer layer 61 may be imparted with flame retardancy in order to suppress breakage during thermal runaway. For example, as the material for forming the thermoplastic elastomer layer, a composition containing rubber alone and / or a composition containing rubber and a thermoplastic resin, and a flame retardant may be used. As the flame retardant, conventionally known ones can be used. The thermoplastic elastomer layer 61 may be imparted with conductivity in order to shield electromagnetic waves. For example, as the material for forming the thermoplastic elastomer layer, a composition containing rubber alone and / or a composition containing rubber and a thermoplastic resin, and a conductive agent may be used, or a two-color molding may be performed using a composition containing the material for forming the thermoplastic elastomer layer and a conductive agent. As the conductive agent, conventionally known ones can be used.

[0046] Any method is adopted to manufacture the material for forming the thermoplastic elastomer layer. For example, a method of sufficiently mixing using preliminary mixing means such as a V-type blender, a Henschel mixer, a mechanochemical device, an extrusion mixer, etc., optionally granulating with an extrusion granulator or a briquetting machine, etc., and then melt-kneading and extruding with a melt-kneader can be mentioned. Examples of the melt-kneader include a twin-screw extruder such as a vented twin-screw extruder, a Banbury mixer, a kneading roll, a single-screw extruder, a multi-screw extruder with three or more axes, etc.

[0047] The thermoplastic elastomer layer 61 is obtained by molding a material for forming the thermoplastic elastomer layer. Examples of the molding method include extrusion, calendering, injection molding, rolling, compression molding, press molding, blow molding, three-dimensional laminated modeling, etc., and it is preferably molded by a three-dimensional laminated modeling method. The three-dimensional laminated modeling method is modeling by a 3D printer. As the 3D printer, it is preferable to use a printer of the material extrusion method (MEX method). The material for forming the thermoplastic elastomer layer can be supplied to the 3D printer in the form of pellets, powders, granules, filaments, etc., and it is desirable to perform molding using a type of 3D printer that can use pellet or granular modeling materials. Examples of such printers include those that control the drive of the extrusion nozzle in a gantry system and those that use a robotic arm system. The temperature when molding the material for forming the thermoplastic elastomer layer is, for example, 170 to 260°C. At this time, the thermoplastic elastomer layer may be formed in one layer by lamination by a 3D printer, or may be formed in two or more layers. The thermoplastic elastomer layer 61 may be integrated with the flange portion after molding the thermoplastic elastomer layer alone by three-dimensional laminated modeling or the like, but as described later, it is preferably molded directly on the flange portion.

[0048] The thermoplastic elastomer layer 61 is preferably heat-sealed to at least one of the upper flange 24 and the lower flange 44. By adopting such a method, there is an advantage that it is not necessary to provide an adhesive layer. Further, by adopting such a method, it is also possible to integrally mold a case formed of a material containing a synthetic resin and a material forming the thermoplastic elastomer layer to obtain a case body. As such an integral molding method, for example, integration of the thermoplastic elastomer layer and a case or the like formed of a material containing a synthetic resin by hot press molding, or forming the thermoplastic elastomer layer on a case or the like formed of a material containing a synthetic resin by the above-described three-dimensional lamination molding method can be mentioned. From the viewpoint of manufacturing efficiency, it is more preferable to directly mold the thermoplastic elastomer layer on a case or the like formed of a material containing a synthetic resin by the three-dimensional lamination molding method. At this time, for the purpose of improving the heat-sealing property, a case or the like formed of a material containing a synthetic resin may be heated before or during molding by a 3D printer. This heating temperature is, for example, 40 to 160°C.

[0049] In a particularly preferred embodiment of the present invention, the thermoplastic elastomer layer 61 is formed of a material containing either or both of an olefin rubber and a polyolefin resin, and the upper case is formed of a material containing a polyolefin resin. By forming the thermoplastic elastomer layer 61 and the upper case 22 from the same polyolefin-based material, it becomes possible to perform material recycling of the thermoplastic elastomer layer and the upper case 22 together after use. Further, it is also possible to manufacture a new product such as a case using the material recycled together. In another preferred embodiment, the thermoplastic elastomer layer 61 is formed of a material containing an acid-modified polyolefin-based thermoplastic elastomer, and the upper case is formed of a material containing a polyamide resin. In addition, when the lower case 42 is formed of the same material as the material containing the synthetic resin forming the upper case 22, the lower case 42 can also be recycled together.

[0050] The power storage unit 51 is a known secondary battery. The power storage unit 51 stores a predetermined amount of electric power and supplies this electric power to the outside. For example, the power storage unit 51 is a lithium-ion battery. The power storage unit 51 is disposed in an accommodation space S1 formed by the upper case main body 23 and the lower case main body 43. By arranging the upper flange 24 and the lower flange 44 to face each other, the power storage unit 51 is held in the accommodation space S1 formed between the upper case main body 23 and the lower case main body 43.

[0051] For example, the fixing portion 56 has a plurality of bolts 57 and a plurality of nuts 58. The head of the bolt 57 is in contact with the upper flange 24 of the upper case 22 from above the upper flange 24. The shaft portion of the bolt 57 is passed through the through hole of the upper case 22, the through hole of the lower case 42, and the through hole of the chassis 10, respectively. The nut 58 is in contact with the lower flange 44 of the lower case 42 from below the lower flange 44. The nut 58 is fitted to the shaft portion of the bolt 57. The head of the bolt 57 and the nut 58 sandwich the upper flange 24, the lower flange 44, and the chassis 10 in the vertical direction.

[0052] As described above, although one embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and configurations such as changes, combinations, deletions, etc. within the scope not departing from the gist of the present invention are also included.

[0053] The method of recycling the above-described battery pack is also one aspect of the present invention. Specifically, a recycling method preferably includes a recovery step of recovering the upper case and the thermoplastic elastomer layer from the battery pack according to the present invention, a pulverization step of pulverizing the recovered material obtained by the recovery step, and a manufacturing step of manufacturing a recycled molded product containing the pulverized material pulverized by the pulverization step as a raw material.

[0054] As a recovery method in the recovery process of recovering the upper case 22 and the thermoplastic elastomer layer 61 from the battery pack of the present invention, for example, when there are a plurality of bolts 57 and a plurality of nuts 58 that fasten the upper flange 24 and the lower flange 44 as the fixing portion 56, they can be easily recovered by removing them. Further, when the lower case 42 is made of the same material as the material containing the synthetic resin forming the upper case 22, it is preferable to recover the upper case 22, the lower case 42, and the thermoplastic elastomer layer 61 from the battery pack according to the present invention in the recovery process.

[0055] The pulverization method in the pulverization process of pulverizing the recovered material recovered by the recovery process is not particularly limited. For example, it may be pulverized using a cutter such as a rotary cutter. The pulverization particle size of the pulverized material obtained by the pulverization process (hereinafter, also simply referred to as "pulverized material") is not particularly limited as long as it does not interfere with the manufacturing process of the next process. For example, it is sufficient to obtain a pulverized material of Φ1 mm.

[0056] The manufacturing process of manufacturing a recycled molded product containing the pulverized material pulverized by the pulverization process as a raw material is, that is, a process of manufacturing a recycled molded product using the pulverized material as at least a part of the raw material. The content of the pulverized material in the raw material is not particularly limited as long as the effects of the present invention can be obtained. For example, it is preferably in the range of 1 to 50% by mass. When the content of the pulverized material is 1% by mass or more, the effect of recycling can be sufficiently obtained, and when it is 50% by mass or less, the physical properties of the manufactured recycled molded product are less likely to be impaired. From the above viewpoints, the content of the pulverized material is more preferably in the range of 2 to 30% by mass, further preferably in the range of 3 to 10% by mass, and particularly preferably in the range of 3 to 7% by mass. The shape of the recycled molded article is not particularly limited and can take various shapes such as plates, sheets, films, cables, and shaped articles. The molding method is not particularly limited, and examples include extrusion, calendering, injection molding, rolling, compression molding, press molding, blow molding, and the like. In addition, the pulverized material and other raw materials other than the pulverized material can be supplied in the form of pellets, powders, granules, filaments, and the like. The other raw materials other than the pulverized material are not particularly limited, and examples include materials containing a synthetic resin that forms the upper case 22. In addition, if necessary, conventionally known additives such as antioxidants, ultraviolet absorbers, light stabilizers, anti-aging agents, cross-linking agents, antistatic agents, antifogging agents, anti-plating agents, surface treatment agents, fluorescent agents, antifungal agents, bactericides, foaming agents, metal deactivators, mold release agents, pigments, processing aids, etc. can be included.

[0057] The recycled molded article is preferably used for the upper case and / or the lower case in the battery pack.

Examples

[0058] Hereinafter, the present invention will be specifically described with reference to examples (experimental examples). However, the present invention is not limited by the following experimental examples. In the following experimental examples and the like, % is based on mass unless otherwise specified. The evaluation was carried out for the following items.

[0059] 1. Measurement of Adhesion Strength A plate containing a synthetic resin was cut into 10 cm × 20 cm, and after covering the surface with a polyimide (PI) sheet, only a part of the PI sheet was removed so as to form a strip having a width of 1.25 cm in the longitudinal direction to expose the plate surface. On this plate, a material for forming a thermoplastic elastomer layer was laminated in a rectangular shape with a thickness of 3 mm and a width of 10 mm in a single layer by a 3D printer according to the method described in the experimental example. At this time, the contact area between the exposed portion of the plate surface and the material for forming the thermoplastic elastomer layer was about 125 mm 2They were laminated so as to achieve this. Then, the upper surface of the thermoplastic elastomer layer (the surface opposite to the plate containing the synthetic resin) was lined with an aluminum plate of 0.8 mm t to obtain a sample for measuring the tensile shear adhesion strength between the plate containing the synthetic resin and the thermoplastic elastomer layer. Based on JIS K 6850, a shear peel test was carried out on this sample at a test speed of 5 mm / min to evaluate the adhesion strength between the plate containing the synthetic resin and the thermoplastic elastomer layer.

[0060] 2. Measurement of the thickness of the thermoplastic elastomer layer The shape shown in Fig. 3 (thickness 3 mm, corner radius of curvature 20 mm) was formed in a spiral mode on a 15 cm square plate containing synthetic resin by a 3D printer using the method described in the experimental example, with only one layer. At that time, the formation was started from the formation start part shown in Fig. 3. Also, in the range of about 1 cm from the formation start part (the range of the masking part shown in Fig. 3), a packaging PP tape was affixed to the plate in advance as a masking, and after the formation, the masking part was removed together with the thermoplastic elastomer layer. For the obtained thermoplastic elastomer layer thickness measurement sample, as shown in Fig. 4, for the frame-shaped part of the thermoplastic elastomer layer, at the points (a) to (h) shown in Fig. 4, the total thickness including the thermoplastic elastomer layer was measured using a constant pressure thickness measuring machine, and the thickness of the plate containing the synthetic resin was subtracted to obtain the thickness of the thermoplastic elastomer layer at each point.

[0061] 3. Evaluation of sealing performance A 15 cm square plate containing synthetic resin was overlaid on the thermoplastic elastomer layer surface of the above thermoplastic elastomer layer thickness measurement sample, and while gently pressing it by hand, the gap between the plate / thermoplastic elastomer layer was visually confirmed, and the sealing performance was evaluated as follows. Sealing performance OK: No gap can be visually confirmed Sealing performance NG: A gap can be visually confirmed

[0062] <<Materials for forming the thermoplastic elastomer layer>> (Composition (a-1) containing an olefin rubber and a polyolefin resin) As a composition containing an olefin rubber and a polyolefin resin, TREXPLANE (registered trademark) 3555B manufactured by Mitsubishi Chemical Corporation was used. (Composition (a-2) containing a styrene copolymer rubber and a polyolefin resin) As a composition containing a styrene copolymer rubber and a polyolefin resin, TEFABLOCK (registered trademark) SJ4300C manufactured by Mitsubishi Chemical Corporation was used. (Composition (a-3) containing a styrene copolymer rubber and a polyolefin resin) As a composition containing a styrene copolymer rubber and a polyolefin resin, TEFABLOCK (registered trademark) TOSI212 40A manufactured by Mitsubishi Chemical Corporation was used. (Flame retardant (a-4)) As the flame retardant, an intumescent flame retardant containing 50 - 60% of piperazine pyrophosphate, 35 - 45% of melamine pyrophosphate, and 3 - 6% of zinc oxide with respect to the total mass of the phosphorus-based flame retardant composition, ADEKA STAB FP-2500S manufactured by ADEKA Corporation, was used. (Dispersant (a-5)) As the dispersant, an α-olefin - maleic anhydride copolymer (DYCARNA 30M manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 7,800) was used.

[0063] <Material (A-1) for forming a thermoplastic elastomer layer> As the material (A-1) for forming a thermoplastic elastomer layer, 58% by mass of component (a-1), 40% by mass of component (a-4), and 2% by mass of component (a-5) were blended and mixed by hand blending. Then, using a φ30 mm co-rotating twin-screw extruder (model name "BT-30", manufactured by Plastic Engineering Laboratory Co., Ltd., L / D = 30), after melt-kneading under the conditions of a screw rotation speed of 250 rpm and a cylinder temperature of 200 °C, it was dried at 70 °C for 12 hours to obtain pellets (A-1). "L / D" indicates the ratio of the length (L) to the diameter (D) of the screw.

[0064] <Material (A-2) for forming a thermoplastic elastomer layer> As the material (A-2) for forming the thermoplastic elastomer layer, pellets (A-2) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-1) was used.

[0065] <The material (A-3) for forming the thermoplastic elastomer layer> As the material (A-3) for forming the thermoplastic elastomer layer, pellets (A-3) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-2) was used.

[0066] <The material (A-4) for forming the thermoplastic elastomer layer> As the material (A-4) for forming the thermoplastic elastomer layer, pellets (A-4) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-3) was used.

[0067] <<The plate containing a synthetic resin>> (Synthetic resin (b-1)) As the synthetic resin, a polypropylene-based resin: "Novatec PP SA06GA" manufactured by Nippon Polypropylene Corporation (melt flow rate: 60 g / 10 min) was used. (Flame retardant (b-2)) As the flame retardant, an intumescent flame retardant containing 50 to 60% of piperazine pyrophosphate, 35 to 45% of melamine pyrophosphate, and 3 to 6% of zinc oxide with respect to the total mass of the phosphorus-based flame retardant composition, manufactured by ADEKA Corporation, Adeka Stab FP-2500S, a phosphorus-based flame retardant composition, was used. (Dispersant (b-3)) As the dispersant, an α-olefin·maleic anhydride copolymer (manufactured by Mitsubishi Chemical Corporation, Diacarna 30M, weight average molecular weight 7,800) was used. (Fiber (b-4)) As the fiber, a glass fiber mat obtained by needle punching a swirl (spiral) mat (basis weight 880 g / m 2 ) made from continuous roving glass fibers (fiber diameter 23 μm) was used.

[0068] The components (b-1), (b-2), and (b-3) were melt-kneaded (at 230 °C) at a ratio of 68% by mass, 30% by mass, and 2% by mass, respectively, to prepare pellets (B-1) of the resin composition. The above pellets (B-1) were put into an extruder, melted, and then extruded into a sheet shape. Subsequently, the component (b-4) was sandwiched from both sides and laminated on the extruded sheet-shaped resin composition. Next, sheet-shaped resin compositions were laminated on both surfaces, and while applying a pressure of 0.3 MPa using a laminator, heating and pressurization were performed at 230 °C for 4 minutes, and then cooling and solidification were carried out to obtain a plate (stampable sheet, thickness 2.5 mm) containing a synthetic resin.

[0069] (Experimental Example 1-1) The material (A-1) for forming a pellet-shaped thermoplastic elastomer layer was put into a 3D printer (GEM550 manufactured by S. Lab Co., Ltd.), and discharged onto a plate containing a synthetic resin under the set conditions of a lamination pitch of 3 mm, a nozzle diameter of 6 mm, a nozzle temperature of 195 °C, a shaping speed of 20 mm / s, a discharge rate of 1.0, and a table temperature of 80 °C. Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were each shaped. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70 °C as measured by a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the thickness of the thermoplastic elastomer layer and the sealability evaluation sample was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealability were each evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0070] (Experimental Example 1-2) The material for forming the thermoplastic elastomer layer was designated as (A-2). Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were each molded in the same manner as in Experimental Example 1-1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70°C as measured with a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the samples for evaluating the thermoplastic elastomer layer thickness and the sealing property was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealing property were each evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0071] (Experimental Example 1-3) The material for forming the thermoplastic elastomer layer was designated as (A-3). Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were each molded in the same manner as in Experimental Example 1-1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70°C as measured with a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the samples for evaluating the thermoplastic elastomer layer thickness and the sealing property was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealing property were each evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0072] (Experimental Example 1-4) The material for forming the thermoplastic elastomer layer was designated as (A-4). Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were respectively molded in the same manner as in Experimental Example 1-1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70°C as measured by a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the thermoplastic elastomer layer thickness and sealability evaluation samples was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealability were respectively evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0073]

Table 1

[0074] Experimental Examples 1-1 to 1-4 are excellent in sealability and adhesion strength. Note that the plate containing the above synthetic resin is assumed to be the upper case.

[0075] <Evaluation of Material Recyclability> The plate containing the synthetic resin was cut into 10 cm × 10 cm, and on this plate, the material for forming the thermoplastic elastomer layer was laminated by a 3D printer in the method described in the experimental example, with only one layer. This sample was put into a rotary cutter (RC250 type pulverizer manufactured by Yoshikou Co., Ltd.), and pulverized samples with a pulverization particle size of Φ1 mm were respectively prepared. The components of the pulverized samples were adjusted to the ratios shown in Table 2 below. In this evaluation, the "plate containing the synthetic resin" is the same as that used in Experimental Examples 1-1 to 1-4, and the "material for forming the thermoplastic elastomer layer" is pellets obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the components described in Table 2 were used. The pulverized sample obtained above was added to the raw materials in Table 3, and molded products (Experimental Examples 2-1 to 2-2) were manufactured using an injection molding machine "FANUC ROBOSHOTα-S300iA" manufactured by FANUC Corporation. Also, a molded product (Experimental Example 2-3) was manufactured in the same manner as Experimental Examples 2-1 to 2-2 except that the pulverized sample was not included. The main molding conditions for the molded products (Experimental Examples 2-1 to 2-3) are as follows. 1) Temperature conditions: Cylinder temperature (220 °C), mold temperature (60 °C) 2) Injection conditions: Injection pressure (200 MPa), holding pressure (82 MPa) 3) Metering conditions: Screw rotation speed (50 rpm), back pressure (15 MPa)

[0076]

Table 2

[0077] 4. Evaluation of Flame Retardancy UL94 Using the molded products (1 / 16-inch test bars) prepared in each experimental example, the flame retardancy was evaluated by a vertical combustion test in accordance with the UL94 standard. The "total combustion time" is the sum of the flaming combustion times during the combustion test. The "number of drips" is the number of particles (drips) that fall from the test piece during the combustion test. The "judgment" is the grade determined by (1) the combustion time after the test piece is exposed to the flame, (2) the total combustion time of 5 samples, (3) the combustion reach position of each test piece, (4) ignition by drips, and (5) red heat after the second exposure to the flame, as defined in the UL94 standard.

[0078] 5. Measurement of Tensile Strength Using the molded products (JIS K7139-A1 or JIS K6251-1, dumbbell test pieces) prepared in each experimental example, the maximum tensile strength (MPa) was measured in accordance with JIS K7161-1.

[0079] 6. Measurement of Bending Strength The molded products (JIS K7139-A1 dumbbell test pieces) prepared in each experimental example were cut to a length of 80 mm, and the flexural modulus (MPa) and maximum flexural strength (MPa) were measured in accordance with JIS K7171.

[0080] The evaluation results of the molded products (Experimental Examples 2-1 to 2-3) obtained above are shown in Table 3.

[0081]

Table 3

[0082] From the results in Table 3, the recycled molded products containing the pulverized samples (Experimental Examples 2-1 to 2-2) were found to be no inferior in flame retardancy and mechanical properties compared to the molded products without the pulverized samples (Experimental Example 2-3). From this, it was confirmed that even when the pulverized material obtained by collecting and pulverizing the upper case and the thermoplastic elastomer layer together was used as the raw material for the next molded product (recycled molded product), it could be molded without problems. Also, when the flame retardancy and mechanical properties of the manufactured recycled molded products were confirmed, it was confirmed that the performance was not impaired.

Explanation of Signs

[0083] 1 Electric vehicle 10 Chassis 10a Opening 15 Tire 20 Battery pack 21 Case 22 Upper case 23 Upper case body 24 Upper flange 25 Flange convex part (convex part) 32 Upper side wall 33 Top wall 42 Lower case 43 Lower case body 44 Lower flange 47 Lower side wall 48 Bottom wall 51 Power storage part 56 Fixing part 57 bolts 58 nuts 61 thermoplastic elastomer layer Axis O1 Receiving space S1

Claims

1. an upper case having an upper case body and an upper flange protruding outward along a horizontal plane from an outer periphery of the upper case body, the upper case being made of a material including a synthetic resin; a lower case including a lower case body and a lower flange that protrudes outward from an outer periphery of the lower case body along a horizontal plane and is disposed so as to face the upper flange from below; a storage unit disposed in a storage section defined by the upper case body and the lower case body, The battery pack has a thermoplastic elastomer layer between the upper flange and the lower flange, the thermoplastic elastomer layer being formed of rubber alone and / or a composition including rubber and a thermoplastic resin.

2. The battery pack according to claim 1 , wherein the thermoplastic elastomer layer is formed from a material containing either or both of an olefin-based rubber or a polyolefin-based resin.

3. The battery pack according to claim 1 or 2, wherein the synthetic resin includes a thermoplastic resin.

4. The battery pack according to claim 1 , wherein the synthetic resin comprises a polyolefin resin.

5. 3. The battery pack according to claim 1, wherein the upper case is formed from a resin fiber composite material in which fibers are mixed with a synthetic resin.

6. 6. The battery pack of claim 5, wherein the fibers comprise glass fibers.

7. 6. The battery pack of claim 5, wherein the resin fiber composite material is a stampable sheet.

8. 3. The battery pack of claim 1, wherein the thermoplastic elastomer layer is in direct contact with at least one of the upper flange and the lower flange.

9. The battery pack according to claim 1 or 2, further comprising a protrusion protruding upward from the upper flange.

10. 3. The method for manufacturing a battery pack according to claim 1, wherein the thermoplastic elastomer layer is heat-sealed to at least one of the upper flange and the lower flange.

11. The method for manufacturing a battery pack according to claim 1 or 2, wherein the thermoplastic elastomer layer is formed by a three-dimensional additive manufacturing method.

12. 3. A method for producing a recycled molded product, comprising: a recovery step of recovering an upper case and a thermoplastic elastomer layer from the battery pack according to claim 1 or 2; a crushing step of crushing the material recovered in the recovery step; and a production step of producing a recycled molded product containing the crushed material obtained in the crushing step as a raw material.

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