Battery

Abstract

To provide a battery with excellent defect suppression in electrode stacks. [Solution] The battery 1 comprises an electrode stack 2, an outer casing 3 that houses the electrode stack 2, and a resin member 4 disposed between the electrode stack 2 and the outer casing 3. The electrode stack 2 is shaped like a rectangular parallelepiped, and the resin member 4 is positioned to cover the stacked end face at the long side of the electrode stack 2 and a portion of two adjacent and opposing surfaces to the stacked end face at the long side.

Description

Technical Field

[0001] The present disclosure relates to a battery.

Background Art

[0002] Examples of batteries in which an electrode laminate is enclosed in an exterior body and a resin is disposed inside the exterior body include those described in Patent Documents 1 to 3. Patent Document 1 discloses a sealed battery including an electrode body, an exterior body that houses the electrode body in a sealed state, and an elastic body that fills the interior of the exterior body so as to cover the entire electrode body. Patent Document 2 discloses a laminate-type solid battery having an electrode laminate and an exterior body made of a laminate film that houses the electrode laminate, wherein an insulating member that abuts at least one surface of the laminated end faces of the electrode laminate is disposed inside the exterior body, the insulating member has an inclined surface that inclines outward from the electrode laminate in a cross-sectional view along the lamination direction, and the angle formed by the inclined surface and the laminated surface of the electrode laminate is greater than 90° and less than 180°. Patent Document 3 discloses an all-solid-state battery cell in which an electrode laminate is enclosed in an exterior material, the electrode laminate includes a current collector tab that extends from an end portion, the current collector tab is connected to a terminal that is led out from an end portion of the all-solid-state battery cell, and a first heat transfer material is disposed inside the exterior material so as to contact the electrode laminate and the exterior material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 1

Summary of the Invention

[0004] In conventional batteries where resin components are simply arranged, there was a risk of delamination or detachment due to the expansion and contraction of the electrode stack. Furthermore, the electrode stack had weak corners, which could lead to the loss of active material due to friction or impact.

[0005] This disclosure is made in view of the above circumstances and aims to provide a battery that excels in suppressing defects in electrode stacks. [Means for solving the problem]

[0006] The means for solving the above problems include the following embodiments. <1> A battery comprising an electrode stack, an outer casing housing the electrode stack, and a resin member disposed between the electrode stack and the outer casing, wherein the electrode stack is shaped like a rectangular parallelepiped, and the resin member is disposed to cover the stacked end face at the long side end of the electrode stack and a portion of two faces adjacent to and facing the stacked end face at the long side end. <2> The resin member has thermal conductivity <1> The battery listed. <3> The resin member has insulating properties <1> or <2> The battery listed. <4> The resin member is an elastic body. <1> ~ <3> The battery listed in one of the following items. <5> It is a solid-state battery. <1> ~ <4> The battery listed in one of the following items. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a battery that exhibits excellent defect suppression in electrode stacks. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of a conventional battery. [Figure 2]This is a schematic cross-sectional view showing another example of a conventional battery. [Figure 3] This is a schematic cross-sectional view showing an example of a battery related to this disclosure. [Figure 4] This is a schematic cross-sectional view showing another example of the battery related to this disclosure. [Modes for carrying out the invention]

[0009] The battery described herein will be explained in detail below with reference to the drawings. The following figures are schematic representations, and the size and shape of each part have been exaggerated as appropriate for ease of understanding.

[0010] (battery) The battery according to this disclosure comprises an electrode stack, an outer casing housing the electrode stack, and a resin member disposed between the electrode stack and the outer casing, wherein the electrode stack is shaped like a rectangular parallelepiped, and the resin member is arranged to cover the stacked end face at the long side of the electrode stack and a portion of two faces adjacent to and facing the stacked end face at the long side. Furthermore, the battery according to this disclosure is preferably a solid-state battery, and more preferably an all-solid-state battery. The solid-state battery includes an all-solid-state battery having a solid electrolyte as an electrolyte between electrodes, and the solid electrolyte may contain less than 10% by mass of electrolyte relative to the total amount of electrolyte. Furthermore, the battery relating to this disclosure is preferably a rechargeable battery.

[0011] The method for manufacturing a battery according to the embodiment of this disclosure will be explained below with reference to the figures.

[0012] Figure 1 is a schematic cross-sectional view showing an example of a conventional battery. The battery 1 shown in Figure 1 comprises an electrode stack 2, an outer casing 3 that houses the electrode stack 2, and a resin member 4 positioned between the electrode stack 2 and the outer casing 3. The resin member 4 is positioned only on the stacked end faces at the long side ends of the electrode stack 1. Furthermore, the battery 1 shown in Figure 1 has an air gap between the electrode stack 2 and the outer casing 3. Figure 2 is a schematic cross-sectional view showing another example of a conventional battery. The battery 1 shown in FIG. 2 includes an electrode laminate 2, an exterior body 3 that houses the electrode laminate 2, and a resin member 4 disposed between the electrode laminate 2 and the exterior body 3, and the resin member 4 is disposed only on the laminated end faces at the long-side direction ends of the electrode laminate 1.

[0013] In the case of the battery 1 shown in FIGS. 1 and 2, the electrode laminate 2 has weak strength at the corner portions, and there is a risk that loss of active material or the like may occur due to rubbing, impact, or the like. Also, peeling or loss may occur as the electrode laminate 2 expands and contracts.

[0014] FIG. 3 is a schematic cross-sectional view showing an example of the battery according to the present disclosure. The battery 1 shown in FIG. 3 includes an electrode laminate 2, an exterior body 3 that houses the electrode laminate 2, and a resin member 4 disposed between the electrode laminate 2 and the exterior body 3, and the resin member 4 is disposed so as to cover the laminated end faces at the long-side direction ends of the electrode laminate 2 and a part of two surfaces adjacent to and facing the laminated end faces at the long-side direction ends. Also, the battery 1 shown in FIG. 3 has a gap between the laminated end face on the long side of the electrode laminate 2 and the inner wall surface of the exterior body 3. Further, although not shown in FIG. 3, the lamination direction of the current collector, the positive electrode active material layer, the electrolyte layer, the negative electrode active material, etc. of the electrode laminate 2 is perpendicular to the normal direction of the two opposing surfaces, and the end face of the long-side direction end of the electrode laminate 2 in contact with the resin member 4 in FIG. 3 is the end face formed by laminating a plurality of single cells constituting the electrode laminate 2. FIG. 4 is a schematic cross-sectional view showing another example of the battery according to the present disclosure. The battery 1 shown in Fig. 4 includes an electrode laminate 2, an exterior body 3 that houses the electrode laminate, and a resin member 4 disposed between the electrode laminate 2 and the exterior body 3. The resin member 4 is arranged to cover the laminated end face at the long-side direction end of the electrode laminate 2 and a part of two faces that are adjacent to and face the laminated end face at the long-side direction end. Also, the battery 1 shown in Fig. 3 has a gap between the laminated end face on the long side of the electrode laminate 2 and the inner wall face of the exterior body 3. Further, although not shown in Fig. 4, the stacking direction of the current collector, the positive electrode active material layer, the electrolyte layer, the negative electrode active material, etc. of the electrode laminate 2 is perpendicular to the normal direction of the two opposing faces. The end face at the long-side direction end of the electrode laminate 2 that is in contact with the resin member 4 in Fig. 4 is the end face formed by stacking a plurality of unit cells constituting the electrode laminate 2. The difference between the battery 1 shown in Fig. 3 and the battery shown in Fig. 4 is mainly the difference in the shape of the exterior body 3.

[0015] As for the battery according to the present disclosure as shown in Figs. 3 and 4, since the resin member 4 is arranged to cover the laminated end face at the long-side direction end of the electrode laminate 2 and a part of two faces that are adjacent to and face the laminated end face at the long-side direction end, the corner portion of the electrode laminate 2 with weak strength is protected. Also, since the resin member 4 has a portion that covers a part of the two faces that are adjacent to and face the laminated end face at the long-side direction end, the heat dissipation efficiency is improved, the cooling efficiency of the electrode laminate 2 is improved, peeling and dropping due to the expansion and contraction of the electrode laminate 2 are suppressed, and it is estimated that the defect suppression property of the electrode laminate 2 is excellent.

[0016] Regarding the amount of the resin member 4 covering a part of the two opposing faces, there is no particular limitation. However, from the perspective of defect suppression of the electrode laminate 2, it is preferable that a region at a distance of 0.1 mm or more from each end of the two opposing faces in the electrode laminate 2 is covered, more preferably a region at a distance of 0.5 mm or more is covered, and particularly preferably a region at a distance of 1 mm or more and 100 mm or less is covered.

[0017] The electrode laminate 2 preferably has at least a current collector, a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer. A specific configuration of the electrode stack 2 could be, for example, a stack made by stacking unit electrode stacks. The unit electrode laminate can be any known form, but examples include current collector / positive electrode active material layer / electrolyte layer / negative electrode active material layer / current collector, current collector / positive electrode active material layer / electrolyte layer / negative electrode active material layer / current collector / negative electrode active material layer / electrolyte layer / positive electrode active material layer / current collector, etc.

[0018] The material, shape, and size of the exterior body 3 are not particularly limited and can be appropriately selected as desired, and known forms can also be used. In particular, the outer casing 3 is preferably a can-shaped outer casing, more preferably a can-shaped metal outer casing, and even more preferably a rectangular can-shaped metal outer casing.

[0019] The material of the resin member 4 is not particularly limited; any resin member capable of conducting heat generated in the electrode laminate 1 is acceptable, and known resin materials can be used. Furthermore, it is preferable that the resin member 4 has thermal conductivity. As the resin having thermal conductivity, a known thermally conductive resin can be used, and a mixture of resin and metal filler is also preferred. The resin member 4 may be in the form of a sheet or a paste. Furthermore, it is preferable that the resin member 4 has insulating properties. In particular, the resin member 4 is preferably an elastic material. Examples of elastic materials include those containing resins such as butadiene rubber (BR), acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and butyl rubber (isobutylene-isoprene rubber). The shape of the resin member 4 is not particularly limited; it can be any desired shape, except that it is positioned to cover the laminated end surface at the long side end of the electrode laminate 2 and a portion of two surfaces adjacent to and facing the laminated end surface at the long side end.

[0020] Furthermore, as shown in Figures 3 and 4, the battery according to this disclosure preferably has an internal void, and the resin member 4 is in contact with the void. By the resin member 4 being in contact with the void, the heat dissipation efficiency is improved, and the cooling efficiency of the electrode stack 2 is improved.

[0021] Furthermore, the battery according to this disclosure may have a bipolar electrode having a positive electrode active material layer on one side of the current collector and a negative electrode active material layer on the side opposite to the current collector foil, and a laminate sheet that covers the side members (e.g., terminals) and is heat-welded to the side members.

[0022] <Components that make up a battery> For example, aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil can be used as the current collector. The thickness of the current collector may be, for example, 1 μm to 100 μm.

[0023] Here, the thickness of each layer, such as the current collector, positive electrode active material layer, and negative electrode active material layer, is the average value of measurements taken at 10 arbitrarily selected locations.

[0024] The positive electrode active material layer contains a positive electrode active material capable of intercalating and releasing charge carriers such as lithium ions. The positive electrode active material can be any material usable as a positive electrode active material for lithium-ion secondary batteries, such as a lithium composite metal oxide having a layered rock salt structure, a metal oxide with a spinel structure, or a polyanionic compound. Furthermore, two or more positive electrode active materials may be used in combination. In this embodiment, the positive electrode active material layer contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0025] The negative electrode active material layer can be any element, alloy, or compound capable of intercalating and releasing charge carriers such as lithium ions, and is not particularly limited. For example, the negative electrode active material can be Li, or carbon, metal compounds, elements or compounds thereof that can be alloyed with lithium. Examples of carbon include natural graphite, artificial graphite, or hard carbon (difficult-to-graphitize carbon) or soft carbon (easily graphitized carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon and tin. In this embodiment, the negative electrode active material layer contains graphite as a carbon-based material.

[0026] The positive electrode active material layer and the negative electrode active material layer may further contain conductive additives, binders, electrolytes (polymer matrix, ion-conducting polymer, electrolyte solution, etc.) to enhance electrical conductivity, and electrolyte-supporting salts (lithium salts) to enhance ionic conductivity. The components contained in the positive electrode active material layer and the negative electrode active material layer, or the mixing ratio of such components, and the thickness of the positive electrode active material layer and the negative electrode active material layer are not particularly limited, and conventionally known knowledge regarding lithium-ion secondary batteries may be referenced as appropriate. The thickness of the positive electrode active material layer and the negative electrode active material layer is, for example, 2 μm to 150 μm. Conventionally known methods such as the roll-coating method may be used to form the positive electrode active material layer or the negative electrode active material layer on the surface of the current collector. To improve the thermal stability of the positive electrode active material layer or the negative electrode active material layer, a heat-resistant layer may be provided on the surface of the current collector (one side or both sides), or on the surface of the positive electrode active material layer or the negative electrode active material layer. The heat-resistant layer may, for example, contain inorganic particles and a binder, and may also contain additives such as thickeners.

[0027] Conductive additives are added to enhance the conductivity of the positive electrode active material layer or the negative electrode active material layer. Examples of conductive additives include acetylene black, carbon black, and graphite.

[0028] Examples of binders include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber; thermoplastic resins such as polypropylene and polyethylene; imide resins such as polyimide and polyamideimide; alkoxysilyl group-containing resins; acrylic resins such as poly(meth)acrylic acid; styrene-butadiene rubber (SBR); alginates such as carboxymethylcellulose, sodium alginate, and ammonium alginate; water-soluble cellulose ester crosslinks; and starch-acrylic acid graft polymers. These binders can be used individually or in combination. Examples of solvents include water and N-methyl-2-pyrrolidone (NMP).

[0029] The electrolyte layer (separator) is a component placed between the positive electrode active material layer and the negative electrode active material layer to isolate them, preventing short circuits caused by contact between the two electrodes, while allowing charge carriers such as lithium ions to pass through. The electrolyte layer prevents short circuits between adjacent bipolar electrodes when bipolar electrodes are stacked.

[0030] The electrolyte layer may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains electrolytes. Examples of materials constituting the electrolyte layer include polypropylene, polyethylene, polyolefin, and polyester. The electrolyte layer may have a single-layer structure or a multilayer structure. The multilayer structure may include, for example, an adhesive layer, a ceramic layer as a heat-resistant layer, and so on. The electrolyte layer may be impregnated with an electrolyte, or the electrolyte layer itself may be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte.

[0031] Examples of electrolytes impregnated into the electrolyte layer include liquid electrolytes (electrolyte solutions) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or polymer gel electrolytes containing an electrolyte held in a polymer matrix.

[0032] When the electrolyte layer is impregnated with an electrolyte solution, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2 can be used as the electrolyte salt. Furthermore, known solvents such as cyclic carbonates, cyclic esters, linear carbonates, linear esters, and ethers can be used as the non-aqueous solvent. Two or more of these known solvent materials may also be used in combination.

[0033] Examples of side members include current-collecting side members. A current-collecting side member is a side member having a current-collecting section in at least a part of it. The current-collecting section is electrically connected, for example, to a tab in the battery. The current-collecting side member may be entirely a current-collecting section, or only partially a current-collecting section. Examples of materials for the side member include metals such as stainless steel (SUS). The shape of the side member is not particularly limited, but may be, for example, a rectangular parallelepiped.

[0034] The laminate sheet preferably has at least a metal layer, and further has a welding resin layer on the side of the metal layer facing the side member. The laminate sheet may also have a protective layer on the side of the metal layer opposite to the side member. Examples of materials for the welding resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective layer include polyethylene terephthalate (PET) and nylon. The thickness of the welded resin layer is, for example, 40 μm to 100 μm. The thickness of the metal layer is, for example, 30 μm to 60 μm. The thickness of the protective layer is, for example, 20 μm to 60 μm. The overall thickness of the laminate sheet is, for example, 70 μm to 220 μm.

[0035] The battery has a resin layer (e.g., a tab film) disposed on the surface of a pair of sides of the side member. The resin layer covers a portion of the surface of the side member and is interposed between the side member and the laminate sheet. Examples of materials for the resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). The thickness of the resin layer is, for example, 40 μm to 100 μm.

[0036] The battery relating to this disclosure is typically a lithium-ion secondary battery. Applications of the battery include, for example, powering vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. It is particularly preferable for the battery to be used as a power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). Furthermore, the battery relating to this disclosure may be used as a power source for mobile devices other than vehicles (e.g., railways, ships, aircraft), or as a power source for electrical products such as information processing devices.

[0037] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Explanation of Symbols]

[0038] 1: Battery, 2: Electrode laminate, 3: Outer casing, 4: Resin component

Claims

1. Electrode stack and, An outer casing that houses the electrode stack, The system comprises a resin member disposed between the electrode laminate and the outer casing, The electrode stack is shaped like a rectangular parallelepiped, and the resin member is arranged to cover the stacked end face at the long side of the electrode stack and a portion of two adjacent and opposing surfaces. battery.

2. The battery according to claim 1, wherein the resin member has thermal conductivity.

3. The battery according to claim 1, wherein the resin member has insulating properties.

4. The battery according to claim 1, wherein the resin member is an elastic body.

5. The battery according to claim 1, which is a solid-state battery.

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