Manufacturing method for laminated electrode body

Abstract

A manufacturing method for a laminated electrode body according to the present invention, when forming one set of a laminated electrode body in which multiple positive electrode plates, multiple negative electrode plates, and multiple separators are laminated, includes: forming a laminate by repeatedly laminating, multiple times, a negative electrode sheet having multiple sets of negative electrode plates, a first separator sheet having multiple sets of separators, a positive electrode sheet having multiple sets of positive electrode plates, and a second separator sheet having multiple sets of separators; and dividing the laminate into multiple sets of laminated electrode bodies by cutting the laminate for each set, wherein the positive electrode sheet has positive electrode active material layers formed with a gap between each set in the longitudinal direction of the positive electrode sheet.

Description

Manufacturing method for multilayer electrodes

[0001] This invention relates to a method for manufacturing a stacked electrode body.

[0002] Conventionally, an electrode stacking apparatus is known that comprises a positive electrode storage section for housing a positive electrode, a negative electrode storage section for housing a negative electrode, a transfer mechanism for transferring the positive electrode and the negative electrode, and a stacking table on which the positive electrode and the negative electrode transferred from the positive electrode storage section and the negative electrode storage section by the transfer mechanism are stacked with a separator interposed between them (see, for example, Patent Document 1). In this electrode stacking apparatus, a set of stacked electrode assemblies is manufactured by stacking the positive electrode, the negative electrode, and the separator.

[0003] Japanese Patent Publication No. 2014-96212

[0004] In recent years, there has been a growing demand for more efficient methods for manufacturing multilayer electrode assemblies.

[0005] The object of the present invention is to provide a method for manufacturing a stacked electrode body that can be produced more efficiently.

[0006] A method for manufacturing a laminated electrode body according to one aspect of the present invention includes, when forming a set of laminated electrode bodies in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are laminated, the method involves repeatedly laminating a negative electrode sheet having a plurality of sets of negative electrode plates, a first separator sheet having a plurality of sets of separators, a positive electrode sheet having a plurality of sets of positive electrode plates, and a second separator sheet having a plurality of sets of separators multiple times to form a laminate, and dividing the laminate into a plurality of sets of laminated electrode bodies by cutting the laminate into sets, wherein at least the positive electrode sheet has an electrode active material layer formed with gaps between them.

[0007] According to the present invention, a method for manufacturing a stacked electrode body that can be produced more efficiently is available.

[0008] Figure 1 is a perspective view showing the external appearance of an energy storage element according to an embodiment. Figure 2 is an exploded perspective view showing the individual components of the energy storage element according to an embodiment. Figure 3 is an exploded perspective view showing the configuration of a laminated electrode body according to an embodiment. Figure 4A is a schematic diagram showing a method for manufacturing a positive electrode substrate according to an embodiment. Figure 4B is a schematic diagram showing a method for manufacturing a positive electrode substrate according to an embodiment. Figure 4C is a schematic diagram showing a method for manufacturing a positive electrode substrate according to an embodiment. Figure 4D is a schematic diagram showing a method for manufacturing a positive electrode substrate according to an embodiment. Figure 4E is a schematic diagram showing a method for manufacturing a positive electrode substrate according to an embodiment. Figure 5A is a schematic diagram showing a method for manufacturing a negative electrode substrate according to an embodiment. Figure 5B is a schematic diagram showing a method for manufacturing a negative electrode substrate according to an embodiment. Figure 5C is a schematic diagram showing a method for manufacturing a negative electrode substrate according to an embodiment. Figure 6 is a schematic diagram showing an integration device for integrating a positive electrode substrate and a separator substrate according to an embodiment. Figure 7 is a schematic diagram showing a lamination device for laminating an integrated sheet and a negative electrode substrate according to an embodiment. Figure 8 is a perspective view showing a modified laminate. Figure 9 is a perspective view showing a laminate according to an embodiment. Figure 10 is a partial cross-sectional view of a laminate according to an embodiment. Figure 11 is a perspective view showing a cutting device according to an embodiment. Figure 12 is a cross-sectional view showing a laminate in the process of being cut according to an embodiment. Figure 13 is a partial cross-sectional view of a laminate in the process of being cut according to modified example 1. Figure 14 is a partial cross-sectional view of a laminate according to modified example 2. Figure 15 is a partial cross-sectional view of a laminate according to modified example 3.

[0009] (1) A method for manufacturing a laminated electrode body according to one aspect of the present invention includes forming a set of laminated electrode bodies in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are laminated, by repeatedly laminating a negative electrode sheet having a plurality of sets of negative electrode plates, a first separator sheet having a plurality of sets of separators, a positive electrode sheet having a plurality of sets of positive electrode plates, and a second separator sheet having a plurality of sets of separators multiple times to form a laminate, and dividing the laminate into a plurality of sets of laminated electrode bodies by cutting the laminate into sets, wherein at least the positive electrode sheet has an electrode active material layer formed with gaps between it.

[0010] According to the method for manufacturing a laminated electrode body described in (1), the negative electrode sheet, first separator sheet, positive electrode sheet, and second separator sheet are repeatedly laminated multiple times to form a laminate, and each set is cut. Therefore, it is possible to increase the manufacturing speed compared to the case in which a set of laminated electrode bodies is manufactured by individually laminating the positive electrode plate, negative electrode plate, and separator. Furthermore, since the positive electrode sheet has a positive electrode active material layer formed with gaps between each set, the positive electrode active material layer can be easily made smaller than the negative electrode active material layer of the negative electrode sheet simply by cutting along these gaps. As a result, it is possible to provide a method for manufacturing a laminated electrode body that can produce laminated electrode bodies more efficiently.

[0011] (2) In the method for manufacturing a laminated electrode body described in (1) above, a positive electrode tab and a negative electrode tab may be provided on one side of the positive electrode sheet and the negative electrode sheet, and the laminated body may be cut in a direction perpendicular to the side.

[0012] (2) According to the laminated electrode body described above, a positive electrode tab and a negative electrode tab are provided on one side of the positive electrode sheet and the negative electrode sheet, and the laminate is cut in a direction perpendicular to that side, so that interference between the positive electrode tab and the negative electrode tab can be suppressed when the laminate is cut.

[0013] (3) In the method for manufacturing a laminated electrode body described in (1) or (2) above, an insulating coating layer may be formed in the gap in the positive electrode sheet.

[0014] According to the method for manufacturing a laminated electrode body described in (3) above, an insulating coating layer is formed in the gaps in the positive electrode sheet, so it is possible to suppress the detachment of the positive electrode active material layer when cutting the laminated electrode body.

[0015] (4) In the method for manufacturing a laminated electrode body described in (2) above, the division may be performed by cutting the coating layer to divide the laminated electrode body into multiple sets.

[0016] According to the method for manufacturing a laminated electrode body described in (4) above, since the coating layer is cut, the generation of burrs during cutting can be suppressed by the coating layer.

[0017] (5) In the method for manufacturing a laminated electrode body described in (3) or (4) above, adhesive layers may be provided on the surface and back surface of the coating layer.

[0018] According to the manufacturing method of the laminated electrode body described in (4) above, adhesive layers are provided on the front and back surfaces of the coating layer, so that the integrity between the positive electrode sheet and the first separator sheet and the coating layer can be enhanced by the adhesive layers.

[0019] (Embodiments) The method for manufacturing a laminated electrode body according to embodiments (including modified versions thereof) of the present invention will be described below with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit the present invention. Dimensions, etc., are not strictly illustrated in each figure. In each figure, the same or similar components are denoted by the same reference numeral. The names of each component (each component) in this embodiment are those of this embodiment and may differ from the names of each component (each component) in the background art.

[0020] Expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where the direction or orientation is not strictly accurate. For example, two directions being orthogonal does not only mean that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, i.e., include a difference of a few percent. In the following explanation, when the term "insulation" is used, it means "electrical insulation." Insulating materials have a volume resistivity of 1 × 10⁻⁶. ６ Preferably Ωm or more, 1 × 10 ７ Ωm or greater is more preferable, 1 × 10 １０ A value of Ωm or greater is even more preferable.

[0021] [Energy Storage Element] First, an energy storage element equipped with a stacked electrode body will be described. Figure 1 is a perspective view showing the external appearance of an energy storage element 10 according to an embodiment. Figure 2 is an exploded perspective view showing each component of the energy storage element 10 according to an embodiment.

[0022] The energy storage element 10 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 has a flattened rectangular parallelepiped shape (angular). The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery; it may be a secondary battery other than a non-aqueous electrolyte secondary battery, a capacitor, or a primary battery, as long as it uses a stacked electrode body. The energy storage element 10 may also be a solid electrolyte battery.

[0023] As shown in Figure 1, the energy storage element 10 comprises a container 100 and a pair of electrode terminals 200 (positive and negative sides). As shown in Figure 2, a laminated electrode body 400 and a pair of current collectors 300 (positive and negative sides) are housed inside the container 100. Insulating external and internal gaskets are placed between the container 100 and each electrode terminal 200, and between the container 100 and each current collector 300 to enhance electrical insulation and airtightness. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but these are not shown in the illustration. There are no particular restrictions on the type of electrolyte as long as it does not impair the performance of the energy storage element 10, and various types can be selected. In addition to the above components, spacers placed to the side or below the laminated electrode body 400, insulating films that enclose the laminated electrode body 400, etc., may also be placed.

[0024] The container 100 is a rectangular parallelepiped (square or box-shaped) case having a container body 110 with an opening and a lid 120 that closes the opening of the container body 110. With this configuration, after housing the laminated electrode body 400, etc., inside the container body 110, the container body 110 and the lid 120 are welded together to close (seal) the inside. The material of the container 100 (container body 110 and lid 120) is not particularly limited and can be made of weldable (joinable) metals such as stainless steel, aluminum, aluminum alloy, iron, plated steel sheet, etc., and resin can also be used. The container body 110 and the lid 120 may be made of the same material or different materials. If the energy storage element 10 is a pouch-type energy storage element, the container 100 may be a laminate film composed of multiple layers including a metal layer and a resin film layer.

[0025] The container body 110 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100, and has an opening at one end. The lid 120 is a rectangular plate-like member that constitutes the lid of the container 100 and is positioned at one end of the container body 110. A pair of through holes 122 are formed at both ends of the lid 120 into which the shaft portions 210 of each electrode terminal 200, which will be described later, are inserted. The lid 120 is equipped with an injection section (not shown) for injecting electrolyte into the container 100 and a gas discharge valve 121 for discharging gas from inside the container 100 when the internal pressure of the container 100 rises.

[0026] The laminated electrode body 400 is an energy storage element (power generation element) that comprises a positive electrode plate, a negative electrode plate, and a separator, and is capable of storing electricity. Specifically, the laminated electrode body 400 is formed by arranging the positive electrode plate 430 (see Figure 3) and the negative electrode plate 440 (see Figure 3) in layers with a separator 450 (see Figure 3) sandwiched between them. A positive electrode tab 431 protrudes from one end of the positive electrode plate 430 in the longitudinal direction, and a negative electrode tab 441 protrudes from the other end of the negative electrode plate 440 in the longitudinal direction. Therefore, at one end of the laminated electrode body 400, the positive electrode tabs 431 of the positive electrode plate 430 are stacked to form a positive electrode tab bundle 410. On the other hand, at the other end of the laminated electrode body 400, the negative electrode tabs 441 of the negative electrode plate 440 are stacked to form a negative electrode tab bundle 420. In other words, the stacked electrode body 400 comprises a stacked electrode body main body portion 401 and a positive electrode tab bundle 410 and a negative electrode tab bundle 420 protruding from one end and the other end of the stacked electrode body main body portion 401. A detailed explanation of the configuration of the stacked electrode body 400 will be given later.

[0027] A fixing member (not shown) is attached to the laminated electrode body 400 to fix the positive electrode plate 430, the negative electrode plate 440, and the separator 450 together. The fixing member is an insulating tape that fixes the laminated positive electrode plate 430, the negative electrode plate 440, and the separator 450 by sandwiching them in the direction of their lamination. The fixing member does not have to be tape; any member that maintains the laminated state of the positive electrode plate 430, the negative electrode plate 440, and the separator 450 is acceptable.

[0028] The electrode terminal 200 is an electrode terminal that is electrically connected to the laminated electrode body 400 via the current collector 300. The electrode terminal 200 is connected to the current collector 300 by crimping or the like and is attached to the cover body 120. Specifically, the electrode terminal 200 has a shaft portion 210 (rivet portion) that extends downward, and this shaft portion 210 is inserted into the external gasket, the through hole 122 of the cover body 120, the internal gasket, and the through hole 311 of the current collector 300, and is crimped and fixed.

[0029] The current collector 300 is an L-shaped plate member that electrically connects the laminated electrode body 400 and the electrode terminal 200. Specifically, the positive electrode current collector 300 is connected (joined) to the positive electrode tab bundle 410 of the laminated electrode body 400 by welding or the like, and is also connected (joined) to the positive electrode terminal 200 by crimping or the like via the through hole 311. The negative electrode current collector 300 is connected (joined) to the negative electrode tab bundle 420 of the laminated electrode body 400 by welding or the like, and is also connected (joined) to the negative electrode terminal 200 by crimping or the like via the through hole 311. In this embodiment, a structure in which the electrode terminal 200 is arranged above the energy storage element 10 is illustrated, but a structure generally called a side terminal, in which the electrode terminal 200 is arranged on the side of the energy storage element 10, is also possible. The structure comprises a rectangular pipe-shaped container body that houses a stacked electrode body, and a pair of lids that close both ends thereof, with electrode terminals provided on each lid.

[0030] [Laminated Electrode Body] Next, the configuration of the laminated electrode body 400 will be described in detail. Figure 3 is an exploded perspective view showing the configuration of the laminated electrode body 400 according to this embodiment. Specifically, Figure 3 is an exploded perspective view showing the positive electrode plate 430, negative electrode plate 440, and separator 450 provided in the laminated electrode body 400.

[0031] As shown in Figure 3, the laminated electrode body 400 is formed by stacking multiple flat electrode plates. Specifically, the laminated electrode body 400 is formed by alternately stacking positive electrode plates 430 and negative electrode plates 440 with separators 450 in between. In other words, separators 450 are placed at both ends in the stacking direction of the laminated electrode body 400, and inside these separators, the negative electrode plate 440, separator 450, positive electrode plate 430, separator 450, negative electrode plate 440, separator 450, positive electrode plate 430, and separator are repeatedly stacked in that order.

[0032] In this way, by stacking multiple positive electrode plates 430 and multiple negative electrode plates 440, multiple positive electrode tabs 431 and multiple negative electrode tabs 441 are stacked. As a result, as shown in Figure 2, the stacked electrode body 400 is formed with a positive electrode tab bundle 410 consisting of multiple positive electrode tabs 431 and a negative electrode tab bundle 420 consisting of multiple negative electrode tabs 441. These positive electrode tab bundles 410 and negative electrode tab bundles 420 are joined to the positive and negative electrode current collectors 300 by welding or the like, and are electrically connected to the positive and negative electrode terminals 200. The configurations of these positive electrode plates 430, negative electrode plates 440 and separators 450 will be described in more detail below.

[0033] The positive electrode plate 430 comprises a positive electrode current collector foil 432, which is a metal foil, and a positive electrode active material layer 433 formed on the front and back surfaces of the positive electrode current collector foil 432. The positive electrode current collector foil 432 integrally comprises a rectangular positive electrode body portion 434 and a positive electrode tab 431 protruding from one end of the positive electrode body portion 434. Aluminum or an aluminum alloy is used for the positive electrode current collector foil 432.

[0034] On the front and back surfaces of the positive electrode body portion 434, an insulating coating layer 436 is continuously formed along each of the three sides other than the side on which the positive electrode tab 431 is located.

[0035] Any material can be used for the coating layer 436 as long as it has insulating properties. The coating layer 436 may include a large number of inorganic particles and a binder that connects these inorganic particles.

[0036] Examples of main components of inorganic particles include alumina, silica, zirconia, titania, magnesia, ceria, yttria, oxides such as zinc oxide and iron oxide, nitrides such as silicon nitride, titanium nitride and boron nitride, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amethyst, bentonite, asbestos, zeolite, calcium silicate, and magnesium silicate. Among these, alumina, silica, and titania are particularly preferred as the main components of the inorganic particles in the coating layer 436.

[0037] As the main component of the binder of the coating layer 436, for example, fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, fluororubbers such as vinylidene fluoride - hexafluoropropylene - tetrafluoroethylene copolymer, styrene - butadiene copolymer and its hydrogenated product, acrylonitrile - butadiene copolymer and its hydrogenated product, acrylonitrile - butadiene - styrene copolymer and its hydrogenated product, methacrylic acid ester - acrylic acid ester copolymer, styrene - acrylic acid ester copolymer, acrylonitrile - acrylic acid ester copolymer and other synthetic rubbers, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose derivatives such as ammonium salt of carboxymethyl cellulose, polyetherimide, polyamideimide, polyimide such as polyamide and its precursor (polyamic acid, etc.), ethylene - acrylic acid copolymer such as ethylene - ethyl acrylate copolymer, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl acetate, polyurethane, polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyester, etc. can be mentioned.

[0038] Further, the coating layer 436 may be formed of an insulating resin material. Examples of the insulating resin material include polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene - perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), polyamide (PA), ABS resin, etc.

[0039] On the front and back surfaces of the positive electrode main body portion 434, the coating layer 436 is disposed so as to cover the entire portion except the vicinity of the positive electrode tab 431 of the positive electrode active material layer 433. The positive electrode active material layer 433 contains a positive electrode active material, a binder, a conductive material, and the like. Here, although FIG. 3 shows an embodiment in which the coating layer 436 is not disposed in the vicinity of the positive electrode tab 431, the coating layer 436 may be provided in this portion.

[0040] As the positive electrode active material, any known material can be appropriately used as long as it can occlude and release charge-transporting ions. Specifically, as the positive electrode active material, LiM1PO ４ , LiM1SiO ４ , LiM1BO ３ (M1 is one or more metal elements selected from Fe, Ni, Mn, Co, etc.) and other polyanion compounds, lithium titanate, LiM2 ２ O ４ (M2 is one or more metal elements selected from Fe, Ni, Mn, Co, etc.) and other spinel-type lithium transition metal oxides, LiM3O ２ (M3 is one or more metal elements selected from Fe, Ni, Mn, Co, etc.) and other layered lithium transition metal oxides can be used.

[0041] The negative electrode plate 440 includes a negative electrode current collector foil 442 that is a metal foil, and a negative electrode active material layer 443 formed on the front and back surfaces of the negative electrode current collector foil 442. The negative electrode current collector foil 442 integrally includes a rectangular negative electrode main body portion 444 and a negative electrode tab 441 protruding from the other end portion of the negative electrode main body portion 444. Copper or a copper alloy or the like is used for the negative electrode current collector foil 442.

[0042] In the regions on the front and back surfaces of the negative electrode main body portion 444, excluding the vicinity of the negative electrode tab 441, the negative electrode active material layer 443 is disposed so as to cover the entire portion except the vicinity of the negative electrode tab 441. For this reason, the negative electrode active material layer 443 is formed larger in plan view than the opposing positive electrode active material layer 433. The negative electrode active material layer 443 contains a negative electrode active material, a binder, a conductive material, and the like.

[0043] As the negative electrode active material, any known material that can intercept and deintercept charge transport ions can be used as appropriate. Specifically, as negative electrode active materials, lithium metals, lithium alloys, alloys capable of intercepting and deintercepting lithium ions, carbon materials (e.g., graphite, poorly graphitizable carbon, easily graphitizable carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides (Li ４ Ti ５ O １２ (etc.), polyphosphate compounds, or what is commonly called a conversion anode, Co ３ O ４ ya Fe ２ Examples include compounds of transition metals such as P and elements from Group 14 to Group 16.

[0044] The separator 450 is a flat, rectangular, microporous sheet made of, for example, resin. Any known material can be used for the separator 450, as long as it does not impair the performance of the energy storage element 10. Specifically, the separator 450 can be a woven fabric, a nonwoven fabric, or a synthetic resin microporous membrane made of polyolefin resin such as polyethylene, which is insoluble in organic solvents.

[0045] [Method for Manufacturing a Multilayer Electrode Body] A method for manufacturing the multilayer electrode body 400 according to this embodiment will be described.

[0046] <Positive Electrode Substrate> First, a method for manufacturing the positive electrode substrate 500 for forming the positive electrode plate 430 will be described. Figures 4A to 4E are schematic diagrams showing a method for manufacturing the positive electrode substrate 500 according to an embodiment. In Figures 4A to 4E, the dashed lines define a unit region 501 that will become one positive electrode plate 430, and are dashed lines.

[0047] First, as shown in Figure 4A, a long, strip-shaped first strip portion 502 made of metal foil such as aluminum or an aluminum alloy is prepared. Such a long first strip portion 502 is supplied in roll form.

[0048] Next, as shown in Figure 4B, positive electrode active material layers 433 are formed on the front and back surfaces of the roll-shaped first strip portion 502. Specifically, the positive electrode active material layers 433 are formed by coating each unit region 501 on the front and back surfaces of the first strip portion 502. Each positive electrode active material layer 433 is divided with gaps 503 in the longitudinal direction of the first strip portion 502. Each positive electrode active material layer 433 is also positioned with gaps from one side and other sides of the first strip portion 502.

[0049] Next, as shown in Figure 4C, one side of the roll-shaped first strip portion 502 is cut to form a positive electrode tab 431 for each unit region 501. The portion of the unit region 501 other than the positive electrode tab 431 is the positive electrode body portion 434.

[0050] Next, as shown in Figure 4D, a first coat layer 4361 is continuously formed on the front and back surfaces of the first strip-shaped portion 502 along the side of the first strip-shaped portion 502 that does not have a positive electrode tab 431. Furthermore, as shown in Figure 4E, a second coat layer 4362 is formed on the front and back surfaces of the first strip-shaped portion 502, extending to part or all of each gap 503, and connecting to the first coat layer 4361. The first coat layer 4361 and the second coat layer 4362 constitute the coat layer 436. The coat layer 436 is directly formed on the first strip-shaped portion 502. Here, the side coat method using a die head, the inkjet method, etc., can be used to form the coat layer 436. In particular, the side coat method using a die head is preferable compared to the inkjet method because it allows for easier maintenance of the equipment.

[0051] Near the boundary between the coating layer 436 and the positive electrode active material layer 433, the coating layer 436 and the positive electrode active material layer 433 may be separated or overlapping. When they are arranged overlapping, it is possible to prevent the first strip-shaped portion 502 from being exposed at the boundary between the coating layer 436 and the positive electrode active material layer 433.

[0052] The positive electrode substrate 500 is formed by the procedure described above. The positive electrode substrate 500 is wound up to form the first roll body 510 (see Figure 6). Note that the order of the manufacturing method for the positive electrode substrate 500 described above is not limited to this, and for example, the positive electrode tab 431 may be provided after the coating layer 436.

[0053] <Negative Electrode Substrate> Next, a method for manufacturing a negative electrode substrate 600 for forming a negative electrode plate 440 will be described. Figures 5A to 5C are schematic diagrams showing a method for manufacturing a negative electrode substrate 600 according to an embodiment. In Figures 5A to 5C, the dashed lines define a unit region 601 that will become one negative electrode plate 440, and are dashed lines.

[0054] First, as shown in Figure 5A, a long, strip-shaped second strip portion 602 made of metal foil such as copper or a copper alloy is prepared. Such a long first strip portion 602 is supplied in roll form.

[0055] Next, as shown in Figure 5B, a negative electrode active material layer 443 is formed on the front and back surfaces of the roll-shaped second strip portion 602. Specifically, the negative electrode active material is continuously laminated along the entire length on the front and back surfaces of the second strip portion 602. As a result, the negative electrode active material is laminated in each unit region 601, forming the negative electrode active material layer 443. Here, the length of the unit region 601 in the longitudinal direction of the second strip portion 602 is equivalent to the length of the unit region 501 in the longitudinal direction of the first strip portion 502.

[0056] Next, as shown in Figure 5C, one side of the roll-shaped second strip portion 602 is cut, forming a negative electrode tab 441 for each unit region 601. The portion of the unit region 601 other than the negative electrode tab 441 is the negative electrode body portion 444. This forms the negative electrode base 600. The negative electrode base 600 is wound up to become the second roll body 610 (see Figure 7).

[0057] <Method for Integrating the Positive Electrode Substrate and the Separator Substrate> Next, a method for integrating the positive electrode substrate 500 and the separator substrate 490 will be described. Figure 6 is a schematic diagram showing an integrating device 700 for integrating the positive electrode substrate 500 and the separator substrate 490 according to an embodiment. As shown in Figure 6, the integrating device 700 includes a holding part 710, an integrating part 720, and a winding part 730.

[0058] The holding portion 710 comprises a first holding portion 711, a second holding portion 712, and a third holding portion 713. The first holding portion 711 is the part that rotatably holds the first roll body 510. The second holding portion 712 and the third holding portion 713 are parts that rotatably hold the roll-shaped separator base 490, respectively. The separator base 490 is a long, strip-shaped member that becomes a separator 450 when cut. The second holding portion 712 and the third holding portion 713 are positioned to sandwich the first holding portion 711.

[0059] The integration section 720 is the part that integrates the positive electrode base 500 drawn out from the first roll body 510 of the first holding section 711 with each separator base 490 drawn out from the second holding section 712 and the third holding section 713, respectively. The integration section 720 is positioned between the holding section 710 and the winding section 730 and is equipped with a pair of rollers 721. The pair of rollers 721 integrate the positive electrode base 500, which is sandwiched between each separator base 490, by sandwiching it, thereby forming an integrated sheet 590. The integration of each separator base 490 and the positive electrode base 500 may be performed by at least one of crimping, welding, or bonding. After integration, each positive electrode tab 431 on the positive electrode base 500 protrudes from each separator base 490, and the other parts of the positive electrode base 500 are directly covered by each separator base 490. In other words, the separator substrate 490 is in direct contact with the positive electrode active material layer 433 on the front and back surfaces of the positive electrode substrate 500, and with the coating layer 436.

[0060] The winding section 730 is the part that winds the integral sheet 590 into a roll. The roll body (third roll body 530) of the integral sheet 590 wound in the winding section 730 is attached to the lamination device 800, which will be described later.

[0061] <Lamination Method of Integrated Sheet and Negative Electrode Substrate> Next, a method for laminating the integrated sheet 590 and the negative electrode sheet 620 will be described. Figure 7 is a schematic diagram showing a lamination apparatus 800 for laminating the integrated sheet 590 and the negative electrode sheet 620 according to an embodiment. As shown in Figure 7, the lamination apparatus 800 includes a first cutting section 810, a second cutting section 820, and a lamination section 830. The first cutting section 810 and the second cutting section 820 are positioned to sandwich the lamination section 830.

[0062] The first cutting section 810 is the part that cuts the integral sheet 590 to a predetermined length and supplies it to the lamination section 830. The first cutting section 810 comprises a first holding shaft 813, a pair of first rollers 814, a first cutter section 815, and a first conveyor section 816, which are arranged in this order to approach the lamination section 830.

[0063] The first holding shaft 813 is a shaft that rotatably holds the third roll body 530. The pair of first rollers 814 are guide rollers that guide the integral sheet 590 pulled out from the first holding shaft 813 to the first cutter section 815. The first cutter section 815 is a cutter section that cuts the integral sheet 590 to a predetermined length. Here, the predetermined length corresponds to the length of one positive electrode sheet. In this embodiment, the example given is that the predetermined length corresponds to the length of four positive electrode plates 430 lined up, but the predetermined length may also correspond to the length of multiple positive electrode plates 430 other than four. The first conveyor section 816 is a section that supplies the integral sheet 590 of the predetermined length cut by the first cutter section 815 to the lamination section 830.

[0064] In the integral sheet 590 cut at the first cutting section 810, each separator base 490 is a first separator sheet 491 and a second separator sheet 492, each equipped with separators 450 of a length equivalent to multiple sets, and the positive electrode base 500 is a positive electrode sheet 520 corresponding to the length of multiple sets of positive electrode plates 430 (see Figure 10).

[0065] The second cutting section 820 is the part that cuts the negative electrode sheet 620 to a predetermined length and supplies it to the lamination section 830. The second cutting section 820 comprises a second holding shaft 823, a pair of second rollers 824, a second cutter section 825, and a second conveyor section 826, which are arranged in this order to approach the lamination section 830.

[0066] The second holding shaft 823 is a shaft that rotatably holds the second roll body 610. The pair of second rollers 824 are guide rollers that guide the negative electrode base 600, which has been drawn out from the second holding shaft 823, to the second cutter section 825. The second cutter section 825 is a cutter that cuts the negative electrode base 600 to a predetermined length. The predetermined length is the length corresponding to the same number of negative electrode plates 440 as in the case of the positive electrode plates 430. The second conveyor section 826 is the part that supplies the negative electrode base 600 of the predetermined length cut by the second cutter section 825 to the stacking section 830. The negative electrode base 600 of the predetermined length cut by the second cutting section 820 is a negative electrode sheet 620 with a length equivalent to multiple sets of negative electrode plates 440 (see Figure 10).

[0067] The lamination section 830 is the part where a negative electrode sheet 620 of a predetermined length supplied from the second cutting section 820 and an integral sheet 590 of a predetermined length supplied from the first cutting section 810 are laminated. The lamination section 830 is a rectangular parallelepiped box with an open top, and inside it, negative electrode sheets 620 of a predetermined length and integral sheets 590 of a predetermined length are repeatedly laminated alternately and housed. As a result, the negative electrode sheet 620, the first separator sheet 491, the positive electrode sheet 520, and the second separator sheet 492 are repeatedly laminated in this order multiple times.

[0068] In this way, the negative electrode sheet 620, the first separator sheet 491, the second separator sheet 492, and the positive electrode sheet 520 are formed by being drawn out from the roll bodies (third roll body 530, second roll body 610) on which they are wound and then cut out. At this time, the longitudinal direction of the positive electrode sheet 520 and the negative electrode sheet 620 (the longitudinal direction of the laminate 900 described later) is perpendicular to the axial direction of the roll body (the axial direction of the first holding shaft 813 and the second holding shaft 823 in Figure 7). Since the direction in which the laminate 900 described later is cut is parallel to the axial direction, sheets of any size can be formed by adjusting the amount of sheets drawn out from the roll body. With this arrangement, the cutting process for forming the positive electrode tab 431 and the negative electrode tab 441 on the positive electrode sheet 520 and the negative electrode sheet 620 can be easily carried out.

[0069] The negative electrode sheet 620 of a predetermined length and the integrated sheet 590 of a predetermined length are positioned by contacting the inner wall surface of the laminated section 830. The laminated section 830 can be any structure that is capable of positioning the negative electrode sheet 620 of a predetermined length and the integrated sheet 590 of a predetermined length.

[0070] Figure 8 is a perspective view showing a modified laminated section 830a. As shown in Figure 8, the laminated section 830a has a plurality of cylindrical columnar sections 835a arranged in a rectangular frame shape on a flat base 834a. A negative electrode sheet 620 of a predetermined length and an integrated sheet 590 of a predetermined length are positioned by contacting each of the columnar sections 835a.

[0071] In the lamination section 830, the negative electrode sheets 620 of a predetermined length and the integral sheets 590 of a predetermined length, which are repeatedly and alternately laminated, form a laminate 900. Figure 9 is a perspective view showing the laminate 900 according to the embodiment. Figure 10 is a partial cross-sectional view of the laminate 900 according to the embodiment. In Figure 10, one negative electrode sheet 620 and a pair of integral sheets 590 sandwiching this negative electrode sheet 620 are shown separately, but the same applies to the other negative electrode sheets 620 and integral sheets 590.

[0072] As shown in Figure 9, immediately after lamination in the lamination section 830, the topmost and bottommost layers of the laminate 900 are negative electrode sheets 620. After removing the laminate 900 from the lamination section 830, a separator sheet 491 (not shown) is separately attached to the front and back surfaces of the laminate 900. This attachment of the separator sheet may be done during lamination in the lamination section 830, or after cutting, as described later. Furthermore, the negative electrode sheets 620, which form the topmost and bottommost layers, do not necessarily need to have negative electrode active material layers 443 on both sides; the top surface of the topmost negative electrode sheet 620 and the bottom surface of the bottommost negative electrode sheet 620 can omit the negative electrode active material layer 443. Moreover, it is not necessary to attach a separator sheet to the laminate 900; an insulating resin film may also be used.

[0073] <Specific Example of Cutting Method for Laminate> The laminate 900 is divided into four laminated electrode bodies 400 by cutting each set at the position of the dashed line L2 shown in Figure 9. The dashed line L2 corresponds to the position of the second coating layer 4362 shown in Figure 10. Various cutting methods can be used to cut the laminate 900, but a cutting device 850 as shown in Figure 11 may also be used.

[0074] Figure 11 is a perspective view showing a cutting device 850 according to an embodiment. The cutting device 850 comprises a mounting table 851 and a cutting unit 852. A laminate 900 is placed on the mounting table 851. The laminate 900 placed on the mounting table 851 is sent to the cutting unit 852, where it is cut into individual laminated electrode bodies 400.

[0075] Figure 12 is a cross-sectional view showing the laminate 900 in the process of being cut according to the embodiment. As shown in Figure 12, the cutter part 853 provided in the cutting part 852 divides the laminate by cutting the second coat layer 4362. During cutting, the edge of the first strip-shaped portion 502 (positive electrode current collector foil 432) of the positive electrode sheet 520 is sealed by the second coat layer 4362, so that the edge of the first strip-shaped portion 502 does not form a burr. Furthermore, even after cutting, the edge of the first strip-shaped portion 502 (positive electrode current collector foil 432) of the positive electrode sheet 520 is fixed by the second coat layer 4362. Therefore, after cutting, it is possible to prevent the edge of the positive electrode sheet 520 from interfering with the second strip-shaped portion 602 of the negative electrode sheet 620 and causing a short circuit.

[0076] [Effects, etc.] As described above, according to this embodiment, the negative electrode sheet 620, the first separator sheet 491, the positive electrode sheet 520, and the second separator sheet 492 are repeatedly stacked in this order multiple times to form a laminate 900, and each set is cut. Therefore, compared to the case in which the positive electrode plate 430, the negative electrode plate 440, and the separator 450 are stacked individually to manufacture one set of laminated electrode bodies 400, the manufacturing speed can be increased. Furthermore, since the positive electrode sheet 520 has a positive electrode active material layer 433 formed with a gap 503 between each set, the positive electrode active material layer 433 can be easily made smaller than the negative electrode active material layer 443 of the negative electrode sheet 620 simply by cutting along the gap 503. As a result, a method for manufacturing laminated electrode bodies that can manufacture laminated electrode bodies 400 more efficiently can be provided.

[0077] Positive electrode tab 431 and negative electrode tab 441 are provided on one side of the positive electrode sheet 520 and the negative electrode sheet 620, and the laminate 900 is cut in a direction perpendicular to that side, so interference between the positive electrode tab 431 and the negative electrode tab 441 when the laminate 900 is cut can be suppressed.

[0078] Since an insulating coating layer 436 is formed in the gap 503 in the positive electrode sheet 520, the coating layer 436 can suppress short circuits between the positive electrode plate 430 and the negative electrode plate 440 in the laminated electrode body 400 after division.

[0079] Since the coating layer 436 is cut, the generation of burrs during cutting can be suppressed by the coating layer 436.

[0080] (Modifications) Modifications of the above embodiments will be described below. In the following description, parts that are the same as those in the above embodiments or other modifications may be denoted by the same reference numerals and their descriptions may be omitted.

[0081] [Modification 1] In the above embodiment, an example was given in which an insulating coating layer 436 is formed in the gap 503 in the positive electrode sheet 520, but the coating layer may not be provided. Figure 13 is a partial cross-sectional view of the laminate 900b according to Modification 1. Figure 13 is a diagram corresponding to Figure 12.

[0082] As shown in Figure 13, in the laminate 900b, no coating layer is formed in the gaps 503b between each positive electrode active material layer 433b on the positive electrode sheet 520b, and the front and back surfaces of the first strip portion 502 are exposed. In this case, the cutter portion 853 of the cutting portion 852 is inserted into the gaps 503b, and the laminate 900b is cut and divided.

[0083] Even in this case, it is possible to increase the manufacturing speed compared to the case in which a set of laminated electrode bodies 400 is manufactured by individually stacking the positive electrode plate 430, the negative electrode plate 440, and the separator 450. Furthermore, since the positive electrode sheet 520b has positive electrode active material layers 433 formed with gaps 503b between each set, the positive electrode active material layer 433b can be easily made smaller than the negative electrode active material layer 443 of the negative electrode sheet 620 simply by cutting along the gaps 503b.

[0084] [Modification 2] In the above embodiment, the case in which no coating layer is formed on the negative electrode sheet 620 was illustrated, but the negative electrode sheet may be provided with a coating layer. Figure 14 is a partial cross-sectional view of the laminate 900c according to Modification 2. Figure 14 corresponds to Figure 10.

[0085] As shown in Figure 14, in the negative electrode sheet 620c of the laminate 900c, multiple negative electrode active material layers 443c are arranged on the front and back surfaces of the second strip-shaped portion 602c with gaps 603c between them. An insulating coating layer 445c is formed in the gaps 603c. Here, the width h2c of the coating layer 445c is smaller than the width h1c of the second coating layer 4362 of the positive electrode sheet 520. This makes the negative electrode active material layer 443c larger than the positive electrode active material layer 433 in plan view. Furthermore, during cutting, the edge of the second strip-shaped portion 602c of the negative electrode sheet 620c is sealed by the coating layer 445c, so that the edge of the second strip-shaped portion 602c does not become a burr. Even after cutting, the edge of the second strip-shaped portion 602c (negative electrode current collector foil 442) of the negative electrode sheet 620c remains fixed by the coating layer 445c. Therefore, after cutting, it is possible to prevent the edge of the negative electrode sheet 620c from interfering with the first strip-shaped portion 502 of the positive electrode sheet 520 and causing a short circuit.

[0086] [Modification 3] (Corresponding to Claim 4) In the above embodiment, the case in which the coating layer 436 is in direct contact with the first strip-shaped portion 502 (positive electrode current collector foil 432) and the separator substrate 490 (separator 450) was illustrated, but an adhesive layer may be interposed between the coating layer and the first strip-shaped portion, and between the coating layer and the separator substrate. Figure 15 is a partial cross-sectional view of the laminate 900d according to Modification 3. Figure 15 is a diagram corresponding to Figure 10.

[0087] As shown in Figure 15, in the laminate 900d, adhesive layers 439d are laminated on the front and back surfaces of each coating layer 436d. Any adhesive material can be used for the adhesive layer 439d. In particular, it is preferable that the adhesive layer 439d is a layer that exhibits adhesiveness upon heating, and may be configured to exhibit adhesiveness when exposed to temperatures above room temperature, for example, 60°C or higher and below the shutdown temperature of the separator 450 (the temperature at which adhesiveness is exhibited is 60°C or higher and below the shutdown temperature of the separator 450).

[0088] As described above, adhesive layers 439d are provided on the front and back surfaces of each coating layer 436d, and the adhesive layers 439d enhance the integration between the positive electrode sheet 520 and the first separator sheet 491 and each coating layer 436d.

[0089] (Other) The above describes a method for manufacturing a stacked electrode body according to an embodiment of the present invention, but the present invention is not limited to the above embodiments. In other words, the embodiments disclosed herein are illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0090] In the above embodiment, an example was given in which the positive electrode active material layer 433 is intermittently formed on the first strip-shaped portion 502, and then the coating layer 436 is formed. However, the positive electrode active material layer 433 may also be formed intermittently after the coating layer 436 is formed on the first strip-shaped portion 502.

[0091] In the above embodiment, it was stated that the energy storage element may be a solid electrolyte battery. In the case of a solid electrolyte battery, the separator corresponds to an isolation layer (solid electrolyte layer) that separates the positive electrode plate and the negative electrode plate.

[0092] The present invention also includes forms constructed by arbitrarily combining the components included in the embodiments and their modified examples.

[0093] This invention can be applied to a manufacturing method for producing a stacked electrode body of an energy storage element.

[0094] 10 Energy storage element 100 Container 200 Electrode terminals 300 Current collector 400 Laminated electrode body 401 Laminated electrode body main body 410 Positive electrode tab bundle 420 Negative electrode tab bundle 430 Positive electrode plate 431 Positive electrode tab 432 Positive electrode current collector foil 433, 433b Positive electrode active material layer 434 Positive electrode main body 436, 436d, 445c Coat layer 439d Adhesive layer 440 Negative electrode plate 441 Negative electrode tab 442 Negative electrode current collector foil 443, 443c Negative electrode active material layer 444 Negative electrode main body 450 Separator 490 Separator substrate 491 First separator sheet 492 Second separator sheet 500 Positive electrode substrate 501, 601 Unit region 502 First strip-shaped portion 503, 503b, 603c Gap 510 First roll body 520, 520b Positive electrode sheet 530 Third roll body 590 Integrated sheet 600 Negative electrode substrate 602, 602c Second strip-shaped portion 610 Second roll body 620, 620c Negative electrode sheet

Claims

1. A method for manufacturing a laminated electrode body, comprising: forming a set of laminated electrode bodies comprising a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators, by repeatedly stacking a negative electrode sheet having a plurality of sets of negative electrode plates, a first separator sheet having a plurality of sets of separators, a positive electrode sheet having a plurality of sets of positive electrode plates, and a second separator sheet having a plurality of sets of separators multiple times to form a laminate; and dividing the laminate into a plurality of sets of laminated electrode bodies by cutting the laminate into sets, wherein the positive electrode sheet has positive electrode active material layers formed with gaps between sets in the longitudinal direction of the positive electrode sheet.

2. A positive electrode tab and a negative electrode tab are provided on one side of the positive electrode sheet and the negative electrode sheet, and the laminate is cut in a direction perpendicular to the side, the method for manufacturing a laminated electrode body according to claim 1.

3. The method for manufacturing a laminated electrode body according to claim 1, wherein an insulating coating layer is formed in the gap in the positive electrode sheet.

4. The method for manufacturing a laminated electrode body according to claim 3, wherein the division is performed by cutting the coating layer, thereby dividing the laminated electrode body into multiple sets.

5. The method for manufacturing a laminated electrode body according to claim 3 or 4, wherein adhesive layers are provided on the surface and back surface of the coating layer.

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