Battery module and manufacturing method thereof

Abstract

To provide a battery module in which a large current can be extracted and gas and moisture transmission can be suppressed with a simple structure, and the manufacture of which is easy.SOLUTION: A battery module includes a power storage module and an exterior body that accommodates the power storage module internally. The exterior body includes a pair of sheet-shaped structures disposed to have the power storage module held from both sides in a thickness direction. The sheet-shaped structure has a metal sheet disposed at an end surface of the power storage module in the thickness direction, and a laminate sheet disposed so as to surround the metal sheet. The metal sheet is electrically connected to the power storage module. An inner side surface of the laminate sheet is bonded to a side surface of the metal sheet. In the pair of sheet-shaped structures, outer peripheral parts of their laminate sheets are bonded together directly or indirectly.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present application relates to a battery module and a manufacturing method thereof. [Background technology]

[0002] It is known that when moisture penetrates into a non-aqueous electrolyte secondary battery, the non-aqueous electrolyte deteriorates and the battery performance is reduced. Therefore, it is necessary to suppress the penetration of moisture into the battery. A battery capable of suppressing the penetration of moisture into the battery is described in, for example, Patent Document 1.

[0003] On the other hand, in the field of batteries, improving output is also one of the issues. Usually, secondary batteries are provided with electrode terminals protruding from the side, and current is taken from there. However, when taking current from an electrode terminal provided on the side of a battery, there is a problem that the area of ​​the terminal is small and a large current cannot be taken. To address this problem, a technology is known in which a current collector (terminal) is provided on both end faces of an electrode body to increase the area of ​​the terminal and make it possible to take out a large current. Such a technology is described, for example, in Patent Documents 2 and 3.

[0004] Patent Document 2 discloses an electricity storage module including a laminate and a reinforcing member provided on the laminate, the laminate including a first electrode including a first current collector and a first active material layer provided on a first surface of the first current collector, a second current collector and a second active material layer provided on a second surface of the second current collector and having a polarity different from that of the first active material layer, the second electrode being laminated on the first electrode such that the second active material layer faces the first active material layer, and a frame-shaped spacer provided between the first current collector and the second current collector so as to surround the first active material layer and the second active material layer when viewed from the stacking direction of the first electrode and the second electrode, for sealing the space between the first current collector and the second current collector, the spacer including a first inner side surface facing the space and a first outer side surface opposite to the first inner side surface, the reinforcing member provided on the first outer side surface so as to cover the first outer side surface over the entire periphery of the first outer side surface, and having a metal layer arranged along the first outer side surface.

[0005] According to Patent Document 2, it is possible to extract a large current from the end face of the electricity storage module. Also, according to Patent Document 2, a reinforcing member having a metal layer is disposed over the entire side face of the electricity storage module, which makes it possible to suppress gas and moisture permeation.

[0006] Patent Document 3 discloses a lithium ion battery module having a first metal sheet, a storage element, and a second metal sheet in this order, in which the storage element includes a lithium ion cell in which a positive electrode collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode collector are laminated in this order, the positive electrode collector and the negative electrode collector are in the outermost layers, and an electrolyte is enclosed by sealing the outer peripheries of the positive electrode active material layer and the negative electrode active material layer, and the lithium ion battery module includes a conductive elastic member disposed between the positive electrode collector in the outermost layer of the storage element and the first metal sheet, and / or between the negative electrode collector in the outermost layer of the storage element and the second metal sheet, and the first metal sheet and the second metal sheet are insulated from each other. The document also discloses a lithium ion battery module that includes a battery outer container that houses the above-mentioned storage element, the battery outer container including a first metal sheet and a second metal sheet, the first metal sheet and the second metal sheet having a contact surface that contacts an elastic member and an exposed surface that is exposed to the outside of the battery outer container.

[0007] According to Patent Document 3, it is possible to extract a large current from an end face of an electricity storage module. Also, according to Patent Document 3, gas and moisture permeation can be suppressed by housing an electricity storage element in a battery outer container including a first metal sheet and a second metal sheet. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-53892 A [Patent Document 2] Patent Publication No. 2022-27201 [Patent Document 3] Patent Publication No. 2021-34141 Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, the electricity storage modules described in Patent Documents 2 and 3 make it possible to extract a large current from the end faces, and also to suppress the permeation of gas and moisture into the battery interior.

[0010] However, in Patent Document 2, a spacer is formed on the side of the power generating element, and an auxiliary member is further arranged around the entire outer periphery of the spacer. When arranging the auxiliary member, it may be necessary to use a resin compatible with the spacer as an adhesive. In other words, there is a certain degree of difficulty in the sealing process aimed at suppressing gas and moisture permeation.

[0011] The electricity storage module of Patent Document 3 uses a laminate sheet with an exposed metal layer as an exterior body, and the process of exposing the metal layer is difficult to a certain extent. For example, Patent Document 3 describes that the metal layer is exposed by performing a solvent treatment, a heat treatment, a flame treatment, or the like on the laminate sheet. [Means for solving the problem]

[0012] As one aspect for solving the above-mentioned problems, the present disclosure provides a battery module comprising: an energy storage module in which electrodes and electrolyte layers are alternately stacked; and an exterior body that houses the energy storage module, wherein the exterior body has a pair of sheet-like structures arranged to sandwich the energy storage module from both sides in the thickness direction, wherein the sheet-like structures have a metal sheet arranged on an end face in the thickness direction of the energy storage module and a laminate sheet arranged to surround the periphery of the metal sheet, wherein the metal sheet is electrically connected to the energy storage module, the inner surface of the laminate sheet is joined to the side of the metal sheet, and the outer peripheries of the laminate sheets in the pair of sheet-like structures are directly or indirectly joined to each other.

[0013] In the battery module, the exterior body may include a frame member arranged to surround the periphery of the storage module, and an outer periphery of a laminate sheet of one of the pair of sheet-like structures may be joined to one surface of the frame member, and an outer periphery of a laminate sheet of the other sheet-like structure may be joined to the other surface of the frame member. The metal sheet may be thicker than the laminate sheet. Furthermore, the storage module may be a bipolar storage module.

[0014] As one aspect for solving the above-mentioned problems, the present disclosure provides a method for manufacturing a battery module, comprising: a first joining step of placing a laminate sheet around a metal sheet and joining the inner surface of the laminate sheet to a side surface of the metal sheet to obtain a sheet-like structure; an arrangement step of sandwiching a storage module in which electrodes and separators are alternately stacked between a pair of sheet-like structures from the thickness direction and placing a metal sheet on an end surface in the thickness direction of the storage module; and a second joining step of directly or indirectly joining the outer peripheries of the laminate sheets of the pair of sheet-like structures after the arrangement step. Effect of the Invention

[0015] In the battery module of the present disclosure, a metal sheet is disposed on an end surface in the thickness direction of the power storage module, and a large current can be taken out from the end surface of the battery module. In addition, in the battery module of the present disclosure, a pair of laminate sheets to which a metal sheet is bonded is used to seal the power storage module inside the exterior body, and therefore, gas and moisture permeation into the interior of the exterior body can be suppressed with a simple structure. Furthermore, in the battery module of the present disclosure, the metal sheet and the laminate sheet are separate members, and a sheet-like structure can be easily formed by bonding them, so that the battery module can be easily manufactured.

[0016] According to the manufacturing method of the battery module of the present disclosure, the above-mentioned battery module can be manufactured through a simple process without requiring any complicated steps. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a plan view of the battery module 100. [Diagram 2] 2 is a cross-sectional view of the battery module 100 taken along line II-II in FIG. [Diagram 3] 2 is a cross-sectional view of an end portion of the power storage module 10. FIG. [Figure 4] 1A is a diagram showing a laminate sheet 23 made of one laminate sheet, and FIG. 1B is a diagram showing a laminate sheet 23 obtained by joining a pair of laminate sheets X cut in half along the length direction. [Diagram 5] 2 is a cross-sectional view of a battery module 200. FIG. [Figure 6] FIG. 2 is a cross-sectional view of a battery module 300. [Figure 7] FIG. 2 is a cross-sectional view of a battery module 400. [Figure 8] A flowchart of the manufacturing method of the battery module 100 is shown. [Figure 9] A schematic diagram of a manufacturing method for the battery module 100 is shown. [Figure 10] A schematic diagram of a manufacturing method for a battery module 200 is shown. [Figure 11] A schematic diagram of a manufacturing method for a battery module 300 is shown. [Figure 12] A schematic diagram of a manufacturing method for a battery module 400 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [Battery module] The battery module of the present disclosure will be described using a battery module 100 as one embodiment. Fig. 1 shows a plan view of the battery module 100. Fig. 2 shows a cross-sectional view of the battery module 100 taken along line II-II in Fig. 1.

[0019] As shown in Figs. 1 and 2, a battery module 100 includes an electricity storage module 10 in which electrodes and separators are alternately stacked, and an exterior body 20 that houses the electricity storage module 10 therein.

[0020] <Energy storage module 10> The power storage module 10 has a plurality of electrodes and a plurality of electrolyte layers, and the electrodes and electrolyte layers are alternately stacked. The power storage module 10 may be a non-aqueous secondary battery or an all-solid-state secondary battery. The power storage module 10 may also be a bipolar type power storage module. In the following, a case where the power storage module 10 is a bipolar type non-aqueous lithium ion secondary battery will be exemplified. A cross-sectional view of an end portion of the power storage module 10 is shown in FIG. 3.

[0021] The electricity storage module 10 includes an electrode stack 18 and a sealing member 19 provided on the entire side surface of the electrode stack 18. The electricity storage module 10 also includes an electrolyte therein. Each component will be described below.

[0022] (Electrode laminate 18) The electrode stack 18 includes a plurality of bipolar electrodes 14 and a plurality of separators 15, and the bipolar electrodes 14 and the separators 15 are alternately stacked. The number of bipolar electrodes 14 and separators 15 is not particularly limited and may be appropriately set according to the desired battery performance. The electrode stack 18 further includes an end positive electrode 16 arranged at one end in the stacking direction and an end negative electrode 17 arranged at the other end in the stacking direction.

[0023] The bipolar electrode 14 includes a current collector 11, a positive electrode layer 12 disposed on one surface of the current collector 11, and a negative electrode layer 13 disposed on the other surface of the current collector 11. In this manner, the bipolar electrode 14 includes electrode layers of different polarities on both surfaces of the current collector 11.

[0024] The current collector 11 is a sheet-shaped conductive member. Examples of the current collector 11 include metal foils such as stainless steel, iron, copper, aluminum, titanium, and nickel. The metal foil may be made of an alloy containing two or more of these metals. The metal foil may be subjected to a predetermined surface treatment such as plating. The current collector 11 may be made of a plurality of metal foils. In this case, the metal foils may be bonded with an adhesive or the like, or may be bonded by pressing or the like. The shape of the current collector 11 is not particularly limited, but may be, for example, approximately rectangular. The thickness of the current collector 11 is not particularly limited, but may be, for example, 5 μm or more and 70 μm or less.

[0025] The positive electrode layer 12 includes a positive electrode active material. The positive electrode active material is not particularly limited and may be appropriately selected from known materials depending on the target battery performance. Examples of the positive electrode active material include a complex oxide, metallic lithium, and sulfur. The composition of the complex oxide includes, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum, and lithium. An example of the complex oxide is olivine-type lithium iron phosphate (LiFePO4).

[0026] The positive electrode layer 12 may contain an optional conductive additive. The conductive additive is not particularly limited and may be appropriately selected from known materials depending on the intended battery performance. Examples of the conductive additive include carbon materials such as acetylene black, carbon black, and graphite.

[0027] The positive electrode layer 12 may optionally contain a binder. The binder is not particularly limited and may be appropriately selected from known materials according to the intended battery performance. Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluorine rubber; thermoplastic resins such as polypropylene and polyethylene; imide-based resins such as polyimide and polyamide-imide; acrylic resins such as alkoxysilyl group-containing resins and poly(meth)acrylic acid; styrene-butadiene rubber (SBR); carboxymethyl cellulose; alginates such as sodium alginate and ammonium alginate; water-soluble cellulose ester crosslinked bodies; and starch-acrylic acid graft polymers.

[0028] The shape of the positive electrode layer 12 is not particularly limited and may be substantially rectangular. The thickness of the positive electrode layer 12 is not particularly limited and may be, for example, in the range of 1 μm to 1 mm. The area of ​​the positive electrode layer 12 may be smaller than that of the negative electrode layer 13. The content of each material in the positive electrode layer 12 is not particularly limited and may be appropriately set according to the intended battery performance. The positive electrode layer 20 may contain materials other than the above-mentioned materials.

[0029] The negative electrode layer 13 includes a negative electrode active material. The negative electrode active material is not particularly limited and may be appropriately selected from known materials depending on the target battery performance. Examples of the negative electrode active material include graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, soft carbon, and other carbon, metal compounds, elements or compounds thereof that can be alloyed with lithium, and boron-added carbon. Examples of elements that can be alloyed with lithium include silicon and tin.

[0030] The negative electrode layer 13 may optionally contain a conductive assistant. The conductive assistant is not particularly limited and may be appropriately selected from known materials depending on the intended battery performance. For example, it may be appropriately selected from conductive assistants that can be applied to the positive electrode layer 12.

[0031] The negative electrode layer 13 may optionally contain a binder. The binder is not particularly limited and may be appropriately selected from known materials depending on the intended battery performance. For example, it may be appropriately selected from binders that are applicable to the positive electrode layer 12.

[0032] The shape of the negative electrode layer 30 is not particularly limited and may be substantially rectangular. The thickness of the negative electrode layer 13 is not particularly limited and may be, for example, in the range of 1 μm to 1 mm. The area of ​​the negative electrode layer 13 may be larger than that of the positive electrode layer 12 from the viewpoint of improving output. The content of each material in the negative electrode layer 13 is not particularly limited and may be appropriately set according to the target battery performance. The negative electrode layer 13 may contain materials other than the above-mentioned materials.

[0033] There is no particular limitation on the method for producing the bipolar electrode 14, and any known method may be used. For example, the materials constituting the electrode layer (positive electrode layer 12 or negative electrode layer 20) may be mixed in a mortar or the like and pressed to obtain an electrode layer, and the obtained electrode layer may be disposed on each surface of the current collector 11. Alternatively, the materials constituting the electrode layer may be mixed with a solvent to obtain a slurry, and the slurry may be applied to each surface of the current collector 11 and dried.

[0034] The separators 15 are disposed between adjacent bipolar electrodes 14, between the bipolar electrodes 14 and the end positive electrodes 17, and between the bipolar electrodes 14 and the end negative electrodes 18. The separators 15 are sheet-like members that prevent short circuits between the electrode layers. The material of the separators 15 is not particularly limited, and examples thereof include porous films and nonwoven fabrics made of polyolefin resins such as polyethylene (PE) and polypropylene (PP). The shape of the separators 15 is not particularly limited, and may be approximately rectangular. The thickness of the separators 15 is not particularly limited, and is, for example, in the range of 1 μm to 1 mm.

[0035] The separator 15 is impregnated with a non-aqueous electrolyte, and functions as an electrolyte layer. The non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte (supporting salt). The non-aqueous solvent is not particularly limited, and examples thereof include cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers. The supporting salt is, for example, a lithium salt. Examples of the lithium salt include LiBF4, LiPF6, LiN(FSO2)2, LiN(SO2CF3)2, and LiN(SO2C2F5)2. The non-aqueous solvent and the indicating salt may be a single type or a mixture of multiple types.

[0036] The end positive electrode 16 has a current collector 11 and a positive electrode layer 12 disposed on one surface of the current collector 11. The end positive electrode 16 is disposed at one end in the stacking direction of the electrode laminate 18. Specifically, the end positive electrode 16 is laminated on the separator 15 so that the positive electrode layer 12 of the end positive electrode 16 and the negative electrode layer 13 of the bipolar electrode 14 face each other.

[0037] The end negative electrode 17 has a current collector 11 and a negative electrode layer 13 disposed on one surface of the current collector 11. The end negative electrode 17 is disposed at the other end in the stacking direction of the electrode laminate 18. Specifically, the end negative electrode 17 is stacked on the separator 15 so that the negative electrode layer 13 of the end negative electrode 17 and the positive electrode layer 12 of the bipolar electrode 14 face each other.

[0038] There is no particular limitation on the method for producing the end positive electrode 16 and the end negative electrode 17, and any known method may be appropriately adopted. For example, the same method as the method for producing the bipolar electrode 14 described above may be adopted.

[0039] (Sealing member 19) The sealing member 19 is provided on the entire side surface of the electrode stack 18, and is a member that holds the multiple bipolar electrodes 14, the end positive electrodes 16, and the end negative electrodes 17, and is made of an insulating resin. The sealing member 19 also serves to seal the electrolyte in the internal space of the electricity storage module 10.

[0040] The material of the sealing member 19 includes, for example, a resin member exhibiting heat resistance, etc. Examples of the resin member exhibiting heat resistance include polyimide, polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and PA66.

[0041] (Method of manufacturing the power storage module 10) A method for manufacturing the electric storage module 10 will be described using an example. First, a sheet-like sealing member (sealing member sheet) is arranged in advance on the current collector 11 included in the bipolar electrode 14, the end positive electrode 16, and the end negative electrode 17. Specifically, a sealing member sheet is arranged so as to surround the periphery of the current collector 11, and the sealing member sheet is bonded to the current collector 11. Next, the bipolar electrode 14, the end positive electrode 16, and the end negative electrode 17 are manufactured using the current collector 11 on which the sealing member sheet is arranged. These obtained electrodes and a separator 15 are laminated to manufacture an electrode laminate 18. Next, a plurality of sealing member sheets provided on the side surfaces of the electrode laminate 18 are bonded to form a sealing member 19. Then, a non-aqueous electrolyte is injected into the internal space of the sealed electric storage module 10, thereby obtaining the electric storage module 10. The method for bonding the sealing member sheet is not particularly limited, and may be, for example, thermal welding. An electric storage module having such a structure is described in, for example, Patent Document 2.

[0042] <Exterior body 20> The exterior body 20 is a member that houses the power storage module 10. As shown in Fig. 2, the exterior body 20 has a pair of sheet-like structures 21, 21 arranged to sandwich the power storage module 10 in the thickness direction.

[0043] (Sheet-like structure 21) The sheet-like structure 21 has a metal sheet 22 arranged on an end surface of the power storage module 10 in the thickness direction, and a laminate sheet 23 arranged so as to surround the periphery of the metal sheet 22. As described above, the power storage module 10 is sandwiched between the pair of sheet-like structures 21, 21. Focusing on the power storage module 10, the metal sheets 22, 22 are arranged on end surfaces on one side and the other side in the thickness direction of the power storage module 10. As shown in Fig. 2, the laminate sheet 23 may be appropriately formed in accordance with the shape of the power storage module 10 so that the sheet-like structure 21 can accommodate the power storage module 10.

[0044] (Metal Sheet 22) The metal sheet 22 is laminated on an end surface of the electricity storage module 10 in the thickness direction, and is electrically connected to the electricity storage module 10. Specifically, the metal sheet 22 is electrically connected to the current collector 11 of the end positive electrode 16 or the end negative electrode 17. Therefore, the metal sheet 22 functions as a current collector. When the metal sheet 22 functions as a current collector, the battery module 100 has a structure in which a current is extracted from the electricity storage module 10 via the metal sheet 22, and therefore, by increasing the area of ​​the metal sheet 22, a large current can be extracted. Since the metal sheet 22 is a member disposed on the end surface of the electricity storage module 10, it is easy to increase the area.

[0045] The material of the metal sheet 22 is not particularly limited, and any suitable metal may be used depending on the purpose. For example, a metal having electrical conductivity may be used. Examples of the metal include stainless steel, iron, copper, aluminum, titanium, and nickel.

[0046] The thickness of the metal sheet 22 is not particularly limited, but may be, for example, 10 μm or more, 50 μm or more, or 100 μm or more. If the thickness of the metal sheet 22 is less than 10 μm, it becomes difficult to join the side surface 22a of the metal sheet 22 and the inner surface 23a of the laminate sheet 23. Although the upper limit is not particularly limited, from the viewpoint of suppressing the increase in size of the battery module 100, the thickness of the metal sheet may be 10 mm or less, 5 mm or less, or 1 mm or less. From the viewpoint of improving durability, the metal sheet 22 may be thicker than the laminate sheet 23. On the other hand, from the viewpoint of miniaturizing the battery module 100 and improving the energy density, the metal sheet 22 may be thinner than the laminate sheet 23.

[0047] The area of ​​the metal sheet 22 is not particularly limited, but from the viewpoint of extracting a large current, it may be 60% or more, or 80% or more, of the area of ​​the current collector 11 arranged on the end face of the power storage module 10. The upper limit is not particularly limited, but from the viewpoint of preventing the battery module 100 from becoming large, the area of ​​the metal sheet 22 may be 200% or less, 150% or less, 120% or less, or 100% or less of the area of ​​the end face of the power storage module 10. The area of ​​the metal sheet 22 is an area calculated from the outer shape of the metal sheet 22. The area of ​​the current collector 11 arranged on the end face of the power storage module 10 is an area calculated from the outer shape of the exposed current collector 11.

[0048] The metal sheet 22 may be laminated directly on the end surface of the energy storage module 10, or may be laminated via another member. It is sufficient that the metal sheet 22 and the energy storage module 10 are electrically connected. For example, the metal sheet 22 may be laminated on the energy storage module 10 via a conductive elastic member. The conductive elastic member is not particularly limited, but examples thereof include an elastic body made of metal fibers and an elastic body made of a mixture of a carbon material and a resin.

[0049] The shape of the metal sheet 22 is not particularly limited and may be appropriately set according to the shape of the end face of the power storage module 10. For example, the metal sheet 22 may have a rectangular flat plate shape. However, as described later, a metal sheet having a protrusion may also be used.

[0050] In addition to functioning as a current collector, the metal sheet 22 also functions as a cooling plate. As described above, the metal sheet 22 has an advantage that the area can be increased, and therefore the heat dissipation can be increased.

[0051] (Laminate sheet 23) The laminate sheet 23 is a member disposed so as to surround the periphery of the metal sheet 22. The laminate sheet 23 has a hole H ( FIG. 4(a) ) formed along the outer shape of the metal sheet 22, and the metal sheet 22 is disposed in the hole H. Then, the metal sheet 22 and the laminate sheet 23 are joined to form the sheet-like structure 21.

[0052] The laminate sheet 23 may be a known laminate sheet. For example, a laminate sheet in which a first resin layer, a metal layer, and a second resin layer are laminated in this order can be used. A laminate sheet having such a configuration is common. The first resin layer functions as a sealant layer and / or a protective layer, and is disposed on the outer surface of the metal layer. The material of the first resin layer may be a thermoplastic resin. For example, polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); polystyrene; polyvinyl chloride; polyamides such as nylon, etc. can be used. The metal layer functions as a gas barrier layer, and is disposed between the first resin layer and the second resin layer. The metal layer may be made of a metal foil such as aluminum, iron, or stainless steel. The second resin layer functions as a sealant layer, and is disposed on the inner surface of the metal layer. That is, the second resin layer is used for joining with other members. The second resin layer is made of a thermoplastic resin. Examples of thermoplastic resins include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); polystyrene; polyvinyl chloride; and polyamides such as nylon. The thickness of the laminate sheet 23 is not particularly limited, but is 50 μm or more and less than 1 mm. The above-mentioned three-layer laminate sheet is an example, and a laminate sheet having three or more layers may be used. For example, a five-layer laminate sheet in which a first resin layer, a third resin layer, a metal layer, a fourth resin layer, and a second resin layer are laminated in this order may be used. The materials of the third resin layer and the fourth resin layer may be appropriately set depending on the purpose.

[0053] Here, as shown in Fig. 4(a), the laminate sheet 23 may be made of one laminate sheet, or may be made by joining a plurality of laminate sheets. For example, as shown in Fig. 4(b), a pair of laminate sheets X cut in half along the length direction and joined together may be used as the laminate sheet 23.

[0054] (Sealing structure of exterior body 20) The sealing structure of the exterior body 20 will be described. As shown in Fig. 2, the inner surface 23a (the outer peripheral surface of the hole H) of the laminate sheet 23 is joined to the side surface 22a of the metal sheet 22. That is, the sheet-like structure 21 has a joint 24 that joins the inner surface 23a of the laminate sheet 23 and the side surface 22a of the metal sheet 22. The joint 24 is formed around the entire periphery of the inner surface 23a of the laminate sheet 23 (the side surface 22a of the metal sheet 22).

[0055] In addition, in the pair of sheet-like structures 21, 21, the outer peripheries 23b of the laminate sheets 23 are directly joined to each other. That is, the exterior body 20 has a joint 25 that joins the outer peripheries 23b of the pair of laminate sheets 23. The joint 25 is formed around the entire periphery of the outer periphery 23b of the laminate sheet 23.

[0056] In this manner, exterior body 20 seals electricity storage module 10 therein by having joints 24, 25. This makes it possible to suppress permeation of gas and moisture into exterior body 20.

[0057] At the joint 25 (periphery 23b of laminate sheet 23), the laminate sheets 23 are guaranteed to be insulated from each other, and are structured so that the metal layers included in the laminate sheets 23 do not come into contact with each other. However, from the viewpoint of further improving the insulation and suppressing short circuits caused by contact between the metal layers, an insulation treatment (edge ​​insulation treatment) may be applied to the outer periphery 23b of the laminate sheet 23. Since the edge insulation treatment is well known, a detailed explanation will be omitted here, but for example, the method described in Patent Document 2 may be appropriately adopted.

[0058] <Another form of battery module 1> Although the battery module 100 uses a flat metal sheet 22, the battery module of the present disclosure is not limited to this. For example, a metal sheet having a protrusion may be used. Fig. 5 shows a cross-sectional view of a battery module 200 using a metal sheet 122 having a protrusion.

[0059] 5, the exterior body 120 includes a pair of sheet-like structures 121, 121, and the sheet-like structure 121 includes a metal sheet 122 having a convex portion, and a laminate sheet 23. The metal sheet 122 includes a flat plate portion 122a and a convex portion 122b protruding outward in the thickness direction from the flat plate portion 122a. The flat plate portion 122a has a larger area than the convex portion 122b, and is disposed on an end face of the energy storage module 10 in the thickness direction. Since the metal sheet 122 and the energy storage module 10 are electrically connected, the convex portion 122b may be used as a terminal.

[0060] Here, the thickness of the metal sheet 122 will be described. The thickness of the metal sheet 122 is the sum of the thicknesses of the flat plate portion 122a and the protruding portion 122b. The thickness of the metal sheet 122 is not particularly limited, but may be, for example, 20 μm or more, 100 μm or more, 200 μm or more, 10 mm or less, or 2 mm or less. The thickness of the flat plate portion 122a is not particularly limited, but may be 10 μm or more, 50 μm or more, 100 μm or more, 5 mm or less, or 1 mm or less. The thickness of the protruding portion 122b is not particularly limited, but may be 10 μm or more, 50 μm or more, 100 μm or more, 5 mm or less, or 1 mm or less.

[0061] The metal sheet 122 and the laminate sheet 23 are joined in the following manner. As shown in Fig. 5, the inner surface 23a of the laminate sheet 23 and the side surface 122ba of the protrusion 122b (the side surface of the metal sheet 122) are joined. That is, the sheet-like structure 121 has a joint 124 that joins the protrusion 122b (the metal sheet 122) and the laminate sheet 23. The joint 124 is formed around the entire inner surface 23a of the laminate sheet 23 (the side surface 122ba of the protrusion 122b).

[0062] 5, the inner peripheral portion 23c of the laminate sheet 23 and the outer peripheral portion 122aa of the flat plate portion 122a may be joined. That is, the sheet-like structure 121 may have a joint portion 126 that joins the flat plate portion 122a and the laminate sheet 23. The joint portion 126 is formed around the entire inner peripheral portion 23c (the outer peripheral portion 122aa of the flat plate portion 122a) of the laminate sheet 23. In this way, the sheet-like structure 121 further has the joint portion 126, so that the metal sheet 122 and the laminate sheet 23 can be firmly joined.

[0063] <Other forms of battery modules 2> Another embodiment of the battery module using a metal sheet having protrusions will now be described. Fig. 6 shows a cross-sectional view of a battery module 300 having another embodiment.

[0064] As shown in FIG. 6, the exterior body 220 includes a pair of sheet-like structures 221, 221, and the sheet-like structure 221 includes a metal sheet 222 having a convex portion and a laminate sheet 23. The metal sheet 222 includes a flat portion 222a and a convex portion 222b protruding outward in the thickness direction from the flat portion 222a. There may be one convex portion 222b, but there may also be multiple convex portions 222b. The more the number of convex portions 222b, the greater the surface area of ​​the metal sheet 222 and the greater the heat dissipation. The thickness of the metal sheet 222 is the same as that of the metal sheet 122.

[0065] The metal sheet 222 and the laminate sheet 23 are joined in the following manner. As shown in Fig. 6, the inner surface 23a of the laminate sheet 23 and the side surface 222aa of the flat plate portion 222a (the side surface of the metal sheet 122) are joined. That is, the sheet-like structure 221 has a joint 224 that joins the flat plate portion 222a (metal sheet 222) and the laminate sheet 23. The joint 224 is formed around the entire periphery of the inner surface 23a of the laminate sheet 23 (the side surface 222aa of the flat plate portion 222a).

[0066] <Other forms of battery modules 3> In the battery module 100, the outer periphery 23b of the laminate sheet 23 of the pair of sheet-like structures 21, 21 is directly bonded to each other, but the battery module of the present disclosure is not limited to this form, and the outer periphery of the laminate sheet of each other may be indirectly bonded to each other via another member. A cross-sectional view of the battery module 400 is shown in FIG.

[0067] In addition to the pair of sheet-like structures 21, 21, the exterior body 320 includes a frame-shaped member 327 arranged to surround the periphery of the power storage module 10. The material of the frame-shaped member 327 is not particularly limited, and examples of the material include a laminate sheet such as an aluminum laminate sheet. The frame-shaped member 327 can be obtained by forming a laminate sheet into a frame shape. The size of the frame-shaped member 327 is not particularly limited as long as it can surround the periphery of the power storage module 10. The thickness of the frame-shaped member 327 is not particularly limited, and may be greater than or equal to the thickness of the power storage module 10.

[0068] In the exterior body 320, of the pair of sheet-like structures 21, 21, the outer periphery 23b of the laminate sheet 23 of one sheet-like structure 21 is joined to one surface 327a in the thickness direction of the frame-shaped member 327, and the outer periphery 23b of the laminate sheet 23 of the other sheet-like structure 21 is joined to the other surface 327b of the frame-shaped member 327. That is, the exterior body 320 has a joint 328 that joins the outer periphery 23b of one laminate sheet 23 and one surface 327a in the thickness direction of the frame-shaped member 327, and a joint 329 that joins the outer periphery 23b of the other laminate sheet 23 and the other surface 327a in the thickness direction of the frame-shaped member 327. The joints 328, 329 are formed around the entire outer periphery 23b (surfaces 327a, 327b of the frame-shaped portion 327) of the one and the other laminate sheets 23. This makes it possible to seal the electricity storage module 10 inside the exterior body 320.

[0069] The exterior body 320 has the following advantages by including the frame-shaped member 327. For example, if the exterior body does not have a frame-shaped member, stress is concentrated at the corners formed in the laminate sheet when the exterior body is vacuum-sealed during manufacturing. In addition, when the battery is used, the laminate sheet repeatedly expands and contracts due to heat, which further concentrates stress at the corners. Such stress concentration may cause the corners to wear and be worn down, leading to damage. In contrast, by including the frame-shaped member 327 in the exterior body 320, no corners are formed in the laminate sheet 327, and damage can be suppressed. In addition, by including the frame-shaped member 327 in the exterior body 320, the outer shape of the exterior body 320 can be made small, and the energy density of the entire battery module 400 can be improved.

[0070] As described above, the battery module of the present disclosure has been described using multiple embodiments. According to the battery module of the present disclosure, it is possible to extract a large current, and it is possible to suppress the permeation of gas and moisture into the inside of the exterior body with a simple structure. Furthermore, the battery module of the present disclosure can be easily manufactured because the metal sheet and the laminate sheet are separate members, and the sheet-like structure can be easily formed by joining them.

[0071] In addition, compared to the energy storage module described in Patent Document 2, the energy storage module of Patent Document 2 has a configuration in which the laminate sheet is directly bonded to the sealing member of the electrode stack, so the resin layer of the laminate sheet and the sealing member need to be compatible. That is, the degree of freedom in material selection is narrow. In addition, since the laminate sheet and the sealing member are directly heat-welded, there is a risk that the structure of the sealing member will collapse when heated, causing the electrolyte to leak. In contrast, the battery module of the present disclosure does not have a configuration in which the laminate sheet and the energy storage module are directly bonded, so there is a high degree of freedom in material selection. In addition, there is no risk of the electrolyte inside the energy storage module leaking during bonding.

[0072] Furthermore, compared to the energy storage module described in Patent Document 3, the energy storage module described in Patent Document 3 uses a laminate sheet with an exposed metal layer as an exterior body, and performs solvent treatment, heat treatment, flame treatment, etc. to expose the metal layer. In contrast, the battery module of the present disclosure uses a metal sheet and a laminate sheet, which are separate members, and can be easily bonded to form a sheet-like structure. Therefore, the battery module of the present disclosure can be easily manufactured.

[0073] Although the above describes a number of embodiments of the battery module, these embodiments may be combined with each other. For example, a metal sheet having a protrusion may be used, and a frame-shaped member may be included in the components of the exterior body.

[0074] [Battery module manufacturing method] A manufacturing method of the battery module of the present disclosure will be described using a manufacturing method of the battery module 100, which is one embodiment. A flowchart of the manufacturing method of the battery module 100 is shown in Fig. 8. Also, schematic diagrams of the manufacturing method of the battery module 100 are shown in Fig. 9(a) to (d).

[0075] The manufacturing method of the battery module 100 includes a first joining process S1 in which a laminate sheet 23 is arranged around a metal sheet 22 and an inner surface 23a of the laminate sheet 23 is joined to a side surface 22a of the metal sheet 22 to obtain a sheet-like structure 21; an arrangement process S2 in which a storage module 10 in which electrodes and separators are alternately stacked is sandwiched between a pair of sheet-like structures 21, 21 on both sides in the thickness direction and a metal sheet 22 is arranged on the end surface in the thickness direction of the storage module 10; and a second joining process S3 in which, after the arrangement process S2, the outer periphery 23b of the laminate sheet 23 of the pair of sheet-like structures 21, 21 is directly joined to each other.

[0076] <First joining process S1> The joining step S1 is a step of arranging the laminate sheet 23 around the metal sheet 22, joining the inner surface 23a of the laminate sheet 23 and the side surface 22a of the metal sheet 22, and obtaining a sheet-like structure 21. Figures 9(a) and (b) correspond to the first joining step S1. Specifically, first, the metal sheet 22 is arranged in the hole H of the laminate sheet 23. Next, the inner surface 23a of the laminate sheet 23 and the side surface 22a of the metal sheet 22 are joined to form a joint 24. This results in the sheet-like structure 21. The method of joining the inner surface 23a of the laminate sheet 23 and the side surface 22a of the metal sheet 22 is not particularly limited, and may be heat welding or laser welding. They may also be joined using an adhesive.

[0077] <Placement process S2> The arrangement step S2 is carried out after the first bonding step S1, and is a step of sandwiching the electricity storage module 10, in which a plurality of electrodes and a plurality of separators are alternately stacked, between a pair of sheet-like structures 21, 21 from both sides in the thickness direction, and arranging a metal sheet 22 on the end face in the thickness direction of the electricity storage module 10. Fig. 9(c) corresponds to the arrangement step S2. When the metal sheet 22 is arranged on the end face in the thickness direction of the electricity storage module 10 via another member, the other member is arranged between the metal sheet 22 and the electricity storage module 10 in the arrangement step S2.

[0078] <Second joining process S3> The second joining step S3 is a step of directly joining the outer peripheries 23b of the laminate sheets 23 of the pair of sheet-like structures 21, 21 after the arrangement step S2. The second joining step S3 is shown in FIG. 9(d). This allows the energy storage module 10 to be sealed inside the exterior body 20.

[0079] The method for directly bonding the outer peripheral portion 23b of the laminate sheet 23 is not particularly limited, and may be heat welding or laser welding. They may also be bonded using an adhesive. The second bonding step S2 may be performed in an air atmosphere or in a reduced pressure atmosphere. For example, the second bonding step S3 may be performed while drawing a vacuum inside the exterior body 20, and the energy storage module 10 may be sealed in the exterior body 20.

[0080] The electricity storage module 10 may have a non-aqueous electrolyte injected therein beforehand, but in the second bonding step S3, an electrolyte solution may be injected into the electricity storage module 10. For example, an electrolyte solution injection port extending to the outside of the exterior body 20 may be provided on the side surface of the electricity storage module 10, and the non-aqueous electrolyte may be injected into the electricity storage module 10 through the electrolyte solution injection port.

[0081] <Another embodiment of the manufacturing method of the battery module 1> A description will now be given of a manufacturing method for a battery module 200 of another embodiment. The manufacturing method for the battery module 200 differs from the manufacturing method for the battery module 100 only in the first bonding step, and the other steps are the same.

[0082] In the manufacturing method of the battery module 100, in the first joining step S1, the inner surface 23a of the laminate sheet 23 and the side surface 22a of the flat metal sheet 22 are joined. In contrast, in the manufacturing method of the battery module 200, in the first joining step, the inner surface 23a of the laminate sheet 23 and the side surface 122ba of the protrusion 122b provided on the metal sheet 122 are joined. In addition, in the first joining step, the inner peripheral portion 23c of the laminate sheet 23 and the outer peripheral portion 122aa of the flat portion 122a may be joined. This allows the metal sheet 122 and the laminate sheet 23 to be firmly joined. The method of joining the inner peripheral portion 23c of the laminate sheet 23 and the outer peripheral portion 122aa of the flat portion 122a is not particularly limited, and may be heat welding or laser welding. In addition, they may be joined using an adhesive.

[0083] 10(a) to (d) show schematic diagrams of a manufacturing method for a battery module 200. As shown in Fig. 10(a) to (d), a first joining step is performed using a metal sheet 122 and a laminate sheet 23 to obtain a sheet-like structure 121. Then, an arrangement step and a second joining step are performed using a pair of sheet-like structures 121 and an electricity storage module 10 to obtain a battery module 200.

[0084] <Another embodiment of the manufacturing method of the battery module 2> A description will now be given of a manufacturing method for a battery module 300 of another embodiment. The manufacturing method for the battery module 300 differs from the manufacturing method for the battery module 100 only in the first bonding step, and the other steps are the same.

[0085] In the manufacturing method of the battery module 100, in a first joining step S1, the inner surface 23a of the laminate sheet 23 and the side surface 22a of the flat metal sheet 22 are joined. In contrast, in the manufacturing method of the battery module 300, in the first joining step, the inner surface 23a of the laminate sheet 23 and the side surface 222aa of the flat portion 222a provided on the metal sheet 222 are joined.

[0086] 11(a) to (d) show schematic diagrams of a manufacturing method for a battery module 300. As shown in Fig. 11(a) to (d), a first bonding step is performed using a metal sheet 222 and a laminate sheet 23 to obtain a sheet-like structure 221. Then, a pair of sheet-like structures 221 and an electricity storage module 10 are used to perform an arrangement step and a second bonding step to obtain a battery module 300.

[0087] <Another embodiment of the manufacturing method of the battery module 3> A description will now be given of a manufacturing method for a battery module 400 of another embodiment. The manufacturing method for the battery module 100 and the manufacturing method for the battery module 400 differ only in the arrangement step and the second bonding step, and the other steps are the same.

[0088] In the manufacturing method of the battery module 100, in an arrangement process S2, the storage module 10 is sandwiched between a pair of sheet-like structures 23 from the thickness direction, and a metal sheet 22 is arranged on the end surface of the storage module 10 in the thickness direction, and in a second joining process S3, the outer periphery 23b of each laminate sheet 23 is directly joined. In contrast, in the manufacturing method of the battery module 400, in the arranging step, the power storage module 10 is sandwiched between a pair of sheet-like structures 23 in the thickness direction via a frame-like member 327 surrounding the periphery of the power storage module 10, and the metal sheet 22 is arranged on the end face in the thickness direction of the power storage module 10. In the second joining step, the outer periphery 23b of the laminate sheet 23 of one sheet-like structure 21 of the pair of sheet-like structures 21 is joined to one surface 327a in the thickness direction of the frame-like member 327, and the outer periphery 23b of the laminate sheet 23 of the other sheet-like structure 21 is joined to the other surface 327b of the frame-like member 327. The joining method of the laminate sheet 23 and the frame-like member 327 is not particularly limited, and may be heat welding or laser welding. They may also be joined using an adhesive.

[0089] 12(a) to (d) show schematic diagrams of a manufacturing method for a battery module 300. As shown in Fig. 12(a) to (d), a first joining step is performed using a metal sheet 22 and a laminate sheet 23 to obtain a sheet-like structure 21. Then, an arrangement step and a second joining step are performed using a pair of sheet-like structures 21, a power storage module 10, and a frame-shaped member 327 to obtain a battery module 400.

[0090] As described above, the manufacturing method of the battery module according to the present disclosure has been described using multiple embodiments. According to the manufacturing method of the battery module according to the present disclosure, it is possible to manufacture a battery module capable of sealing an electricity storage module inside an exterior body through a simple process and extracting a large current.

[0091] Although the above describes a number of embodiments of the method for manufacturing a battery module, these embodiments may be combined with each other. For example, the first bonding step may be performed using a metal sheet having a protrusion, and the second bonding step may be performed using a frame member. [Explanation of symbols]

[0092] 10 Energy storage module 11 Current collector 12 Positive electrode layer 13 Negative electrode layer 14 Bipolar Electrode 15 Separator 16 End positive pole 17 End negative electrode 18 Electrode laminate 19 Sealing member 20, 120, 220, 320 Exterior 21, 121, 221, 321 Sheet-like structure 22, 122, 222 Metal Sheet 22a, side 122a, 222a flat plate part 122aa outer circumference 222aa side 122b, 222b convex part 122ba side 23 Laminate sheet 23a Inside surface 23b Outer periphery 23c Inner circumference 24, 124, 224 joint 25 Joint 126 Joint 327 Frame-shaped members 327a side 327b side 328 Joint 329 Joint 100, 200, 300, 400 Battery Module H hole X Laminate sheet

Claims

1. A storage module in which electrodes and electrolyte layers are alternately stacked, and an exterior body that houses the storage module, the exterior body has a pair of sheet-like structures arranged to sandwich the power storage module from both sides in a thickness direction, the sheet-like structure includes a metal sheet disposed on an end surface of the power storage module in a thickness direction, and a laminate sheet disposed so as to surround a periphery of the metal sheet, The metal sheet has one end in a thickness direction electrically connected to the power storage module and the other end in the thickness direction exposed to the outside, The inner surface of the laminate sheet is joined to the side surface of the metal sheet, In the pair of sheet-like structures, the outer peripheries of the laminate sheets are directly or indirectly joined to each other. Battery module.

2. the exterior body includes a frame-shaped member arranged to surround the periphery of the power storage module, Of the pair of sheet-like structures, an outer periphery of the laminate sheet of one of the sheet-like structures is joined to one surface of the frame-shaped member, and an outer periphery of the laminate sheet of the other of the sheet-like structures is joined to the other surface of the frame-shaped member. The battery module according to claim 1 .

3. The battery module according to claim 1 , wherein the metal sheet is thicker than the laminate sheet.

4. The battery module according to any one of claims 1 to 3, wherein the storage module is a bipolar type storage module.

5. A method for manufacturing the battery module of claim 1, comprising: a first joining step of placing the laminate sheet around the metal sheet and joining an inner surface of the laminate sheet to a side surface of the metal sheet to obtain the sheet-like structure; an arrangement step of sandwiching the energy storage module between the pair of sheet-like structures in a thickness direction and arranging the metal sheet on an end surface of the energy storage module in the thickness direction; A second joining step of directly or indirectly joining the outer peripheries of the laminate sheets of the pair of sheet-like structures to each other after the arrangement step. A method for manufacturing a battery module.

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