JP2019016494A - Method for manufacturing multilayer electrode body and method for manufacturing power storage element - Google Patents

Abstract

To provide a method for manufacturing a multilayer electrode body, by which a multilayer electrode body of a large energy density can be manufactured efficiently.SOLUTION: A method for manufacturing a multilayer electrode body according to an embodiment of the present invention comprises the steps of: disposing a positive electrode plate between two separators having an adhesive layer on each face and a negative electrode plate on one of the two separators; laminating the negative electrode plate, one of the two separators, the positive electrode plate and the other separator and in this state, heating and putting a pressure on them; and cutting the two separators so that both ends of the two separators protrude from ends of the positive and negative electrode plates respectively, in order to obtain a sub-unit into which the negative electrode plate, the one separator, the positive electrode plate and the other separator are integrated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a laminated electrode body and a method for manufacturing a storage element.

  Chargeable / dischargeable storage elements are used in various devices such as mobile phones and electric vehicles. In recent years, with higher output and higher performance of these devices, there is a demand for a power storage element that is smaller and has a higher energy density (electric capacity).

  In general, a storage element is formed by alternately stacking a positive electrode plate having a positive electrode active material layer formed on a surface and a negative electrode plate having a negative electrode active material layer formed on a surface through an electrically insulating separator. It has an electrode body. In order to increase the energy density per unit volume in such a storage element, it is effective to make the separator thinner. For this reason, the electrical storage element which formed the separator with the resin film is put in practical use.

  In a power storage device, metal deposits generated by electrodeposition in the negative electrode (for example, metal deposits due to dissolution and precipitation of lithium dendrite or metal foreign matter) may penetrate the separator and cause a short circuit between the positive electrode plate and the negative electrode plate. . Using a bag-shaped electrode plate that is formed by bonding the outer edges of a pair of separators sandwiching the positive electrode plate or the negative electrode plate, a metal species that generates metal ions capable of generating precipitates is mixed in the electrolyte solution in the vicinity of the positive electrode plate. A laminated electrode body that suppresses this and prevents electrodeposition of metal ions in contact with the negative electrode is known.

  Since the bonded portion of the separator does not contribute to charging / discharging, the bonded portion of the separator can occupy a predetermined space inside the power storage element and prevent the energy density of the power storage element from being increased.

  In the laminated electrode body, when the positive electrode plate protrudes from the negative electrode plate in plan view, the current concentrates at the end of the negative electrode plate, and the electrodeposition is promoted locally. For this reason, in the laminated electrode body, the planar dimension of the positive electrode plate needs to be smaller than the planar dimension of the negative electrode plate, which is also a factor that limits the energy density of the storage element.

  Since the separator formed from the resin film is relatively weak against heat, when the energy density of the energy storage device is increased, the separator is damaged by heat, and metal precipitates generated by electrodeposition penetrate the separator and the positive electrode plate. There is a possibility of short-circuiting the negative electrode plate. For this reason, a power storage element has been proposed in which a heat-resistant layer (inorganic layer) is formed on the surface of the separator that comes into contact with the electrode plate to improve the heat resistance of the separator (see JP 2013-143337 A).

JP 2013-143337 A

  In the electricity storage device described in the publication, a positive electrode plate is sandwiched between a pair of separators, and a packaged positive electrode plate in which the pair of separators are bonded to each other on a plan view outside of the positive electrode plate, and the packing is larger than the positive electrode plate and smaller than the separator. A laminated electrode body in which negative electrode plates that are not formed are alternately laminated is accommodated in an exterior material. A plurality of packaged positive plates and a plurality of negative plates are held by sandwiching a plurality of separators with an exterior material at the outer periphery.

  Thus, when laminating a plurality of packaged positive plates and a plurality of negative plates alternately, it is difficult to accurately position the negative plates in the laminated electrode body. Since it is necessary to make the positive electrode plate small so that the positive electrode plate does not protrude from the negative electrode plate, improvement in energy density is hindered. Even if the positive electrode plate is made smaller, it is necessary to accurately position and dispose the negative electrode plate on the packaged positive electrode plate. Therefore, the work of laminating a plurality of packaged positive electrode plates and a plurality of negative electrode plates is difficult. It is complicated and the improvement of production efficiency is limited.

  An object of the present invention is to provide a method for producing a laminated electrode body and a method for producing a power storage element that can efficiently produce a laminated electrode body having a large energy density.

  In the method for manufacturing a laminated electrode body according to one aspect of the present invention, one positive electrode plate is disposed between two separators each having an adhesive layer on both sides, and on one of the two separators. Arranging one negative electrode plate and heating and pressurizing in a state where one of the one negative electrode plate and the two separators, the other one of the positive electrode plate and the two separators are laminated. Both ends of the two separators in order to obtain a subunit that integrates one of the one negative electrode plate, one of the two separators, the one positive electrode plate, and the other of the two separators. Cutting the two separators so as to protrude from the end portions of the positive electrode plate and the negative electrode plate, respectively.

  The manufacturing method of the laminated electrode body which concerns on 1 aspect of this invention thermocompression-bonds one positive electrode plate, two separators which pinch | interpose this positive electrode plate, and one negative electrode plate laminated | stacked on one separator. In this subunit, the relative positions of the positive electrode plate, the separator and the negative electrode plate are relatively accurate. For this reason, even if the difference between the size of the positive electrode plate and the size of the negative electrode plate is reduced, the positive electrode plate can be prevented from protruding from the negative electrode plate and promoting electrodeposition. Moreover, since a positive electrode plate and a negative electrode plate are adhere | attached on the separator, a subunit is hard to deform | transform. Therefore, the subunits can be easily positioned by the guide, and a plurality of subunits can be stacked accurately and quickly. A ratio of the area of the area where the positive electrode plate and the negative electrode plate face each other relative to the area of the separator is relatively large, and a laminated electrode body having a large energy density can be efficiently produced.

It is typical sectional drawing of the subunit formed in the manufacturing method of the laminated electrode body of one Embodiment of this invention. FIG. 2 is a partial enlarged cross-sectional view of a subunit of the laminated electrode body of FIG. 1. It is typical sectional drawing of the electrode unit formed in the manufacturing method of the laminated electrode body of one Embodiment. FIG. 4 is a schematic plan view of the electrode unit in FIG. 3. It is a schematic diagram which shows the process of forming the subunit of FIG. It is typical sectional drawing of the laminated electrode body manufactured by the manufacturing method of the laminated electrode body of one Embodiment. It is a typical exploded perspective view of the electrical storage element manufactured by the manufacturing method of the electrical storage element of one Embodiment.

  In the method for manufacturing a laminated electrode body according to one aspect of the present invention, one positive electrode plate is disposed between two separators each having an adhesive layer on both sides, and on one of the two separators. Arranging one negative electrode plate and heating and pressurizing in a state where one of the one negative electrode plate and the two separators, the other one of the positive electrode plate and the two separators are laminated. Both ends of the two separators in order to obtain a subunit that integrates one of the one negative electrode plate, one of the two separators, the one positive electrode plate, and the other of the two separators. Cutting the two separators so as to protrude from the end portions of the positive electrode plate and the negative electrode plate, respectively.

  According to the method for manufacturing the laminated electrode body, one positive plate, two separators sandwiching the positive plate, and one negative plate laminated on one separator are thermocompression bonded and integrated. Since the subunit is formed, the relative positions of the positive electrode plate, the separator, and the negative electrode plate are relatively accurate in the subunit. For this reason, even if the difference between the size of the positive electrode plate and the size of the negative electrode plate is reduced, the positive electrode plate can be prevented from protruding from the negative electrode plate and promoting electrodeposition. Moreover, since a positive electrode plate and a negative electrode plate are adhere | attached on the separator, a subunit is hard to deform | transform. Therefore, the subunits can be easily positioned by the guide, and a plurality of subunits can be stacked accurately and quickly. A ratio of the area of the area where the positive electrode plate and the negative electrode plate face each other relative to the area of the separator is relatively large, and a laminated electrode body having a large energy density can be efficiently produced.

In the manufacturing method of the laminated electrode body, in order to obtain an electrode unit obtained by laminating a plurality of the subunits and integrating the laminated subunits, the positive plate and the negative electrode of each of the subunits It may further comprise welding separators protruding from the end of the plate. According to this configuration, since the integrated electrode unit is formed by laminating the subunits and welding the end portions of the separator, the laminated electrode body can be manufactured more efficiently by laminating the electrode units. Can do.
Conventionally, a packaged positive electrode plate is formed by sandwiching a positive electrode plate between a pair of separators and bonding or welding the pair of separators on the outside of the positive electrode plate in plan view. Such a packaged positive electrode plate has difficulty in increasing the production efficiency. As described above, manufacturing efficiency can be improved by laminating a plurality of subunits and collectively welding the laminated subunit separators.

  The manufacturing method of the laminated electrode body includes: laminating a plurality of the electrode units; arranging a single negative electrode plate on the separator arranged in the outermost layer; and the plurality of electrode units and the negative electrode plate. You may further provide heating and pressurizing in the laminated state. According to this structure, the laminated electrode body to which all the layers were adhere | attached can be obtained by laminating | stacking several electrode units and one negative electrode plate, and heating and pressurizing.

  The manufacturing method of the laminated electrode body further includes covering an outer periphery of the laminated body of the plurality of electrode units and the negative electrode plate with a resin film before heating and pressurizing the plurality of electrode units and the negative electrode plate. Also good. According to this configuration, since the misalignment of the plurality of electrode units and the negative electrode plate can be prevented at the time of handling when heating and pressurizing the laminate of the plurality of electrode units and the negative electrode plate, the positions of the positive electrode plate and the negative electrode plate can be prevented. The energy density of the laminated electrode body can be increased by reducing the margin for displacement.

  The manufacturing method of the electrical storage element which concerns on 1 aspect of this invention comprises accommodating the laminated electrode body obtained by the said manufacturing method in a case.

  According to the method for manufacturing the power storage element, a stacked electrode body having a large energy density is efficiently manufactured by the manufacturing method of the stacked electrode body, and the power storage element is formed using the stacked electrode body. It can be manufactured efficiently.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

  A method for manufacturing a laminated electrode body according to an embodiment of the present invention includes a step of forming a subunit S as illustrated in FIGS. 1 and 2 (subunit formation step) and a plurality of subunits S. 3 and a step of forming an electrode unit U as illustrated in FIG. 4 (electrode unit forming step) and a step of integrating a plurality of electrode units U to obtain a laminated electrode body B as illustrated in FIG. Integration step).

  As shown in FIG. 1, the subunit S includes two separators 1, one positive electrode plate 2 disposed and fixed between the two separators 1, and two separators 1. And one negative electrode plate 3 which is bonded and fixed to the opposite surface of the positive electrode plate 2. In the subunit S, the two separators 1 have their end portions protruding from the end portions of the positive electrode plate 2 and the negative electrode plate 3.

  As shown in detail in FIG. 2, the separator 1 includes a sheet-shaped resin layer 4, an oxidation-resistant layer 5 laminated on at least a surface of the resin layer 4 facing the positive electrode plate 2, and the resin layer 4 and the oxidation-resistant layer. And a pair of adhesive layers 6 laminated on both surfaces of the laminate of layers 5.

  The positive electrode plate 2 includes a conductive foil-shaped or sheet-shaped positive electrode current collector 7 and a positive electrode active material layer 8 laminated on the surface of the positive electrode current collector 7. More specifically, the positive electrode plate 2 includes an active material region having a rectangular shape in plan view in which the positive electrode active material layer 8 is laminated on the surface of the positive electrode current collector 7, and the positive electrode current collector 7 is activated from the active material region. And a positive electrode tab 9 (see FIG. 4) extending in a strip shape having a width smaller than that of the material region.

  The negative electrode plate 3 includes a conductive foil-shaped or sheet-shaped negative electrode current collector 10 and a negative electrode active material layer 11 laminated on the surface of the negative electrode current collector 10. Specifically, the negative electrode plate 3 has a rectangular active material region in which the active material layer is laminated on the surface of the negative electrode current collector 10, and a strip shape having a width smaller than the active material region from the active material region. The positive electrode tab 9 and a negative electrode tab 12 (see FIG. 4) extending in the same direction as the positive electrode tab 9 with a space therebetween.

  As shown in FIG. 3, the electrode unit U has a plurality of subunits S, and the ends of the separators 1 protruding from the ends of the positive electrode plate 2 and the negative electrode plate 3 of the plurality of subunits S are welded together. Has been.

  In this electrode unit U, the positive electrode plate 2 is adhesively fixed to the separators 1 on both sides, but the negative electrode plate 3 is adhesively fixed only to the separator 1 of the same subunit S, and is attached to the separator 1 of the adjacent subunit S. Is not glued and fixed.

  As shown in FIG. 4, in the electrode unit U, the first welding region R <b> 1 is formed along a pair of opposing side edges where the positive electrode tab 9 and the negative electrode tab 12 of the positive electrode plate 2 and the negative electrode plate 3 do not exist. Is preferred. The electrode unit U includes a second plate in which a plurality of separators 1 are partially welded along a side edge where the positive electrode tab 9 and the negative electrode tab 12 of the positive electrode plate 2 and the negative electrode plate 3 are present and a side edge opposite thereto. The welding region R2 may be formed. In this case, it is preferable that the first welding region R1 and the second welding region R2 are not formed in the vicinity of the corner of the separator 1. Each separator is bent along the side edges of the positive electrode plate 2 and the negative electrode plate 3 in the thickness direction of the positive electrode plate 2 and the negative electrode plate 3 in order to bring the separators 1 into close contact with each other. Since bending in different directions interferes, welding at this portion may cause an excessive load and damage the separator 1.

  As shown in FIG. 6, the laminated electrode body B includes a plurality of laminated electrode units U and one negative electrode arranged on the outer side of the separator 1 arranged on the outermost side in the laminated body of the electrode units U. Plate 3. In this laminated electrode body B, each negative electrode plate 3 is bonded and fixed not only to the separator 1 of the same subunit S but also to the separator 1 of the adjacent subunit S. The laminated electrode body B further includes a resin film 13 that covers the entire laminated body (the outer periphery of the laminated body) of the plurality of electrode units U and one additional negative electrode plate 3.

  In the figure, the thicknesses of the separator 1, the positive electrode plate 2 and the negative electrode plate 3 are drawn large for easy understanding, but the actual separator 1, the positive electrode plate 2 and the negative electrode plate 3 are small in thickness, The thickness in welding area | region R1, R2 of the some separator 1 becomes a very small thing compared with the width | variety of welding area | region R1, R2. For this reason, the part which protrudes from the positive electrode plate 2 and the negative electrode plate 3 including 1st welding area | region R1 of the separator 1 of each electrode unit U is bend | folded along the edge part (side edge) of the positive electrode plate 2 and the negative electrode plate 3. It may be.

  In the method of manufacturing the laminated electrode body, the sub-unit S is formed in the sub-unit forming step, whereby the positive electrode plate 2 and the negative electrode plate 3 are relatively accurately positioned and fixed with respect to the two separators 1. Unit S can be obtained. By laminating a plurality of the subunits S, it is possible to form a laminated electrode body B in which a plurality of positive electrode plates 2 and a plurality of negative electrode plates 3 face each other with high accuracy through the separator 1.

  Thus, in the manufacturing method of the said laminated electrode body, since the positive electrode plate 2 and the negative electrode plate 3 can be aligned and laminated | stacked with high precision by using the subunit S, the positive electrode plate 2 and the negative electrode plate 3 Even if the size difference is reduced, it is possible to prevent the positive electrode plate 2 from protruding from the negative electrode plate 3 and promote electrodeposition. Moreover, in the manufacturing method of the said laminated electrode body, the difference in the magnitude | size of the negative electrode plate 3 and the separator 1 in the subunit S can also be made small. As a result, the area of the positive electrode plate 2, that is, the positive electrode plate 2 and the negative electrode plate 3, compared to the projected area of the laminated electrode body B (the area when viewed from the lamination direction of the separator 1, the positive electrode plate 2 and the negative electrode plate 3). And the area of the region contributed by the electrode plate can be made relatively large to increase the energy density of the laminated electrode body B.

  In addition, since the subunit S is bonded and fixed to the positive electrode plate 2 and the negative electrode plate 3 in addition to the outer edges of the separator 1 being bonded and fixed to each other, the separator 1 is hardly bent. For this reason, the subunit S can be positioned relatively accurately and quickly by bringing a guide or the like into contact with the outer edge of the separator 1, and the laminated electrode body B having a large energy density can be efficiently manufactured.

  In the subunit forming step, one positive electrode plate 2 is disposed between two separators 1 and one negative electrode plate 3 is disposed on one separator 1 of the two separators 1 (arrangement). Step), one negative electrode plate 3, one of the two separators 1, one positive electrode plate 2 and the other of the two separators 1 are heated and pressurized in a state of being laminated in this order (unit heating) Pressure step) and a step (cutting step) of cutting the two separators 1 so that both end portions of the two separators 1 protrude from the end portions of the positive electrode plate 2 and the negative electrode plate 3, respectively.

  The subunit forming step may be performed using the separator 1 that has been cut in advance to the dimensions in the subunit S by performing the cutting step first, but as shown in FIG. You may perform a cutting process, after performing an arrangement | positioning process and a unit heating-pressing process continuously using the base material 1a.

  More specifically, in the arranging step, two separator base materials 1a are continuously supplied and transported in the longitudinal direction, and the two separator base materials 1a in the transported state are cut to the dimensions in the final product. The positive electrode plates 2 are sequentially inserted at equal intervals (a pitch equal to the width of the subunit S), and the negative electrode plates 3 are cut to the dimensions of the final product so as to face the positive electrode plate 2 outside the separator base material 1a. Are arranged sequentially.

  In the unit heating and pressing step, this long laminate is heated and pressurized while being continuously conveyed. Heating and pressurization may be performed simultaneously. Alternatively, the laminate may be pressed after heating before the temperature of the adhesive layer 6 of the separator 1 drops to a temperature at which the adhesive force is lost.

  The continuous conveyance of the laminated body of the separator base material 1a, the positive electrode plate 2, and the negative electrode plate 3 can be performed using, for example, a conveyance belt having releasability.

  The laminated body in the unit heating and pressing step can be heated using, for example, a plate heater H arranged so as to sandwich the laminated body. Moreover, the pressurization in the unit heating and pressurizing step can be performed using, for example, a pair of pressure rollers P that sandwich the laminate. Alternatively, heating and pressurization may be performed simultaneously using a pair of heating rollers that generate heat while sandwiching the laminate.

  The heating temperature in the unit heating and pressing step is set to be equal to or higher than the temperature at which the adhesive layer 6 of the separator 1 exhibits adhesive force and lower than the shutdown temperature of the resin layer 4, and may be, for example, 80 ° C. or higher and 120 ° C. or lower.

  The pressurizing pressure in the unit heating and pressurizing step can be set to, for example, 0.1 N / cm or more and 10.0 N / cm or less by a load per unit length of the pressing roller.

  In the cutting step, the subunit S is sequentially separated by cutting the separator base material 1a with the cutter C to obtain a separator 1 having a predetermined length.

  Here, each component of the subunit S will be described in detail.

  The separator 1 is interposed between the positive electrode plate 2 and the negative electrode plate 3 and prevents the positive electrode plate 2 and the negative electrode plate 3 from being in direct contact with each other in the electricity storage device manufactured using the subunit S. The inside is impregnated with an electrolytic solution, so that charge can be transferred between the positive electrode plate 2 and the negative electrode plate 3 via ions.

  The resin layer 4 of the separator 1 is a layer mainly holding an electrolytic solution, and is formed from a porous resin film.

  Examples of the main component of the resin layer 4 include polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and chlorinated polyethylene. Polyolefins such as polyolefin derivatives and ethylene-propylene copolymers, and polyesters such as polyethylene terephthalate and copolymerized polyesters can be used. Among these, as the main component of the resin layer 4, polyethylene and polypropylene excellent in electrolytic solution resistance, durability, and weldability are preferably used. The “main component” means a component having the largest mass content.

  The lower limit of the average thickness of the resin layer 4 is preferably 5 μm and more preferably 10 μm. On the other hand, the upper limit of the average thickness of the resin layer 4 is preferably 30 μm, and more preferably 20 μm. By setting the average thickness of the resin layer 4 to be equal to or more than the lower limit, it is possible to prevent the resin layer 4 from being broken when the separators 1 are welded to each other. In addition, by setting the average thickness of the resin layer 4 to be equal to or less than the above upper limit, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  The oxidation-resistant layer 5 of the separator 1 is a layer provided mainly for suppressing the resin layer 4 from being oxidized and deteriorated, and includes a large number of inorganic particles and a binder for connecting the inorganic particles.

  As the main component of the inorganic particles, for example, oxides such as alumina, silica, zirconia, titania, magnesia, ceria, yttria, zinc oxide, iron oxide, nitrides such as silicon nitride, titanium nitride, boron nitride, silicon carbide, carbonate Calcium, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate Etc. Among these, alumina, silica and titania are particularly preferable as the main component of the inorganic particles of the oxidation resistant layer 5.

  The lower limit of the average particle size of the inorganic particles of the oxidation resistant layer 5 is preferably 1 nm, and more preferably 7 nm. On the other hand, the upper limit of the average particle diameter of the inorganic particles is preferably 5 μm and more preferably 1 μm. By setting the average particle diameter of the inorganic particles to the above lower limit or more, the ratio of the binder in the oxidation resistant layer 5 can be reduced, and the heat resistance of the oxidation resistant layer 5 can be increased. Moreover, the uniform oxidation-resistant layer 5 can be formed by making the average particle diameter of inorganic particles below the upper limit. The “average particle diameter” is a value measured according to JIS-R1670 using a transmission electron microscope (TEM) or a scanning electron microscope (SEM).

  Examples of the main component of the binder of the oxidation-resistant layer 5 include fluorine resins such as polyvinylidene fluoride and polytetrafluoroethylene, fluororubbers such as vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, and styrene-butadiene copolymer. And hydride thereof, acrylonitrile-butadiene copolymer and hydride thereof, acrylonitrile-butadiene-styrene copolymer and hydride thereof, methacrylate ester-acrylate copolymer, styrene-acrylate ester copolymer, Synthetic rubber such as acrylonitrile-acrylic acid ester copolymer, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), cellulose derivatives such as ammonium salt of carboxymethyl cellulose, polyetherimide Polyimide such as polyamideimide, polyamide and its precursor (polyamic acid etc.), ethylene-acrylic acid copolymer such as ethylene-ethyl acrylate copolymer, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP) ), Polyvinyl acetate, polyurethane, polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyester and the like.

  The lower limit of the average thickness of the oxidation-resistant layer 5 is preferably 2 μm and more preferably 4 μm. On the other hand, the upper limit of the average thickness of the oxidation resistant layer 5 is preferably 10 μm, and more preferably 6 μm. By making the average thickness of the oxidation-resistant layer 5 equal to or more than the lower limit, the oxidation-resistant layer 5 can be prevented from breaking when the separator 1 is bonded and fixed. Further, by setting the average thickness of the oxidation resistant layer 5 to the upper limit or less, the oxidation resistant layer 5 is easily broken when the separators 1 are welded to each other, so that the resin layers 4 can be reliably integrated.

  The adhesive layer 6 of the separator 1 is a layer that adheres the separator 1 to the positive electrode plate 2 and the negative electrode plate 3 while having ion conductivity so as to enable an electrode reaction in the positive electrode plate 2 and the negative electrode plate 3. Specifically, the adhesive layer 6 can exhibit adhesiveness by heating to a temperature exceeding normal temperature, for example, 60 ° C. or higher and lower than the shutdown temperature of the separator 1 (the temperature at which the resin layer 4 melts). Composed.

  The adhesive layer 6 can be formed from a mixed material containing particles exhibiting ionic conductivity and a binder. Specifically, the adhesive layer 6 may be formed of a material including solid electrolyte particles that contain an electrolyte solution to ensure ionic conductivity and a binder that exhibits adhesiveness by heating, ultrasonic vibration, or the like. it can. The adhesive layer 6 preferably has continuous pores so that liquid and gas can pass through.

  The lower limit of the average thickness of the adhesive layer 6 is preferably 0.1 μm, more preferably 0.2 μm, and even more preferably 0.4 μm. On the other hand, the upper limit of the average thickness of the adhesive layer 6 is preferably 5 μm, more preferably 3 μm, and even more preferably 1.2 μm. By setting the average thickness of the adhesive layer 6 to be equal to or more than the lower limit, sufficient adhesiveness can be obtained. Moreover, sufficient ion conductivity can be obtained by setting the average thickness of the adhesive layer 6 to the upper limit or less.

  Examples of the material of the solid electrolyte particles of the adhesive layer 6 include inorganic solid electrolytes, genuine solid polymer electrolytes, polymer gel electrolytes, and the like. Among them, the ion conductivity can be increased. A polymer gel electrolyte solution that is homogeneous and easily adjusts the particle diameter is particularly preferably used.

  The polymer gel electrolyte is one that is made easy to handle by gelling the electrolyte with a polymer. Examples of the polymer that gels the electrolytic solution include vinylidene fluoride-hexafluoropropylene copolymer, polymethylmethacrylic acid, polyacrylonitrile, and the like.

As the electrolytic solution of the polymer gel electrolytic solution, an organic electrolytic solution in which a supporting electrolytic solution is dissolved in an organic solvent is used. A lithium salt is preferably used as the supporting electrolyte. The lithium salt is not particularly limited, for example _{LiPF 6, LiAsF 6, LiBF 4} , LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF ₃ CO) ₂ NLi, (CF ₃ SO ₂ ) ₂ NLi, (C ₂ F ₅ SO ₂ ) NLi, and the like. Among these, LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li that are easily soluble in an organic solvent and exhibit a high degree of dissociation are particularly preferable.

  The organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolytic solution. For example, dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), Carbonates such as butylene carbonate (BC) and methyl ethyl carbonate (MEC), esters such as γ-butyrolactone, methyl formate, ethers such as 1,2-dimethoxyethane, tetrahydrofuran, sulfolane, dimethyl sulfoxide, etc. One or a plurality of sulfur compounds can be used in combination. Among these, carbonates having a high dielectric constant and a wide stable potential region are particularly preferably used.

  As a minimum of the density | concentration of the support electrolyte solution in electrolyte solution, 1 mass% is preferable and 5 mass% is more preferable. On the other hand, as an upper limit of the density | concentration of the support electrolyte solution in electrolyte solution, 30 mass% is preferable and 20 mass% is more preferable. By setting the concentration of the supporting electrolyte in the electrolyte within the above range, relatively high ion conductivity can be obtained.

  The lower limit of the average particle diameter of the solid electrolyte particles is preferably 0.1 μm, and more preferably 0.2 μm. On the other hand, the upper limit of the average particle diameter of the solid electrolyte solution particles is preferably 2 μm, and more preferably 1 μm. By setting the average particle diameter of the solid electrolyte solution particles to be equal to or larger than the lower limit, the solid electrolyte solution particles can be brought into contact with each other to easily impart ion conductivity to the adhesive layer 6. Moreover, it becomes easy to form the contact bonding layer 6 in uniform film shape by making the average particle diameter of a solid electrolyte solution particle | grain below the said upper limit.

  The shape of the solid electrolyte solution particles is preferably a shape having a small sphericity such as a rod shape, a cone shape, or a plate shape so that the contact between the solid electrolyte solution particles can be promoted to increase the ion conductivity.

  The binder of the adhesive layer 6 is not particularly limited as long as it has adhesiveness to the solid electrolyte solution particles and the positive electrode active material layer 8, but the positive electrode active material layer 8 can be heated by heating at a relatively low temperature. An adhesive resin, that is, a polymer material having a relatively low glass transition point and exhibiting adhesiveness is preferably used.

  As a minimum of the glass transition point of a binder, -50 degreeC is preferable and -45 degreeC is more preferable. On the other hand, as an upper limit of the glass transition point of a binder, 50 degreeC is preferable and 45 degreeC is more preferable. By setting the glass transition point of the binder to the lower limit or more, the strength of the adhesive layer 6 can be ensured. Moreover, the separator 1 can be adhere | attached on the positive electrode plate 2 and the opposing separator 1 by the temperature which does not damage the resin layer 4 by making the glass transition point of a binder below the said upper limit.

Examples of the main component of the binder include an acrylic polymer. As the acrylic polymer, a nitrile group-containing acrylic polymer containing a monomer unit having a nitrile group and a (meth) acrylic acid ester monomer unit is suitably used. Here, the monomer unit having a nitrile group is a structural unit obtained by polymerizing acrylonitrile, methacrylonitrile, or the like, for example, and the (meth) acrylic acid ester monomer unit is CH ₂ ═CR ¹ − It is a monomer unit derived from a compound represented by COOR ² (wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group or a cycloalkyl group). A nitrile group-containing acrylic polymer is an ethylenically unsaturated compound formed by polymerizing an ethylenically unsaturated acid monomer in addition to a monomer unit having a nitrile group and a (meth) acrylic acid ester monomer unit. An acid monomer unit may be included. The nitrile group-containing acrylic polymer may be cross-linked.

  The lower limit of the ratio of the solid electrolyte particles in the adhesive layer 6 is preferably 70% by mass, and more preferably 80% by mass. On the other hand, the upper limit of the ratio of the solid electrolyte particles in the adhesive layer 6 is preferably 95% by mass, and more preferably 90% by mass. By setting the ratio of the solid electrolyte particles in the adhesive layer 6 to be equal to or higher than the lower limit, sufficient ion conductivity can be imparted to the adhesive layer 6. Further, by setting the ratio of the solid electrolyte solution particles in the adhesive layer 6 to be equal to or lower than the above upper limit, the adhesive layer 6 can be provided with sufficient adhesiveness by relatively increasing the ratio of the binder.

  As a material of the positive electrode current collector 7 of the positive electrode plate 2, a metal such as aluminum, copper, iron, nickel, or an alloy thereof is used. Among these, aluminum, an aluminum alloy, copper, and a copper alloy are preferable from the balance between high conductivity and cost, and aluminum and an aluminum alloy are more preferable. Moreover, as a formation form of the positive electrode electrical power collector 7, foil, a vapor deposition film, etc. are mentioned, A foil is preferable from the surface of cost. That is, the positive electrode current collector 7 is preferably an aluminum foil. Examples of aluminum or aluminum alloy include A1085P and A3003P defined in JIS-H4000 (2014).

  The lower limit of the average thickness of the positive electrode current collector 7 is preferably 5 μm, more preferably 10 μm. On the other hand, the upper limit of the average thickness of the positive electrode current collector 7 is preferably 50 μm, more preferably 40 μm. By setting the average thickness of the positive electrode current collector 7 to be equal to or more than the lower limit, sufficient strength can be imparted to the positive electrode current collector 7. In addition, by setting the average thickness of the positive electrode current collector 7 to be equal to or less than the above upper limit, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  The positive electrode active material layer 8 is formed from a so-called positive electrode mixture containing a positive electrode active material. Moreover, the positive electrode mixture forming the positive electrode active material layer 8 includes optional components such as a conductive agent, a binder, a thickener, and a filler as necessary.

Examples of the positive electrode active material include complex oxides (Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x ) represented by Li _x MO _y (M represents at least one transition metal). _{MnO 3, Li x Ni α Co} (1-α) O 2, Li x Ni α Mn β Co (1-α-β) O 2, Li x Ni α Mn (2-α) O 4 , etc.), Li _w A polyanion compound (LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ ) represented by Me _x (XO _y ) _z (Me represents at least one transition metal, and X represents, for example, P, Si, B, V, etc.) Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.). The elements or polyanions in these compounds may be partially substituted with other elements or anion species. In the positive electrode active material layer 8, one kind of these compounds may be used alone, or two or more kinds may be mixed and used. The crystal structure of the positive electrode active material is preferably a layered structure or a spinel structure.

  As a minimum of content of the positive electrode active material in the positive electrode active material layer 8, 50 mass% is preferable, 70 mass% is more preferable, 80 mass% is further more preferable. On the other hand, as an upper limit of content of a positive electrode active material, 99 mass% is preferable and 94 mass% is more preferable. By setting the content of the positive electrode active material particles in the above range, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  The conductive agent is not particularly limited as long as it is a conductive material that does not adversely affect battery performance. Examples of such a conductive agent include carbon black such as natural or artificial graphite, furnace black, acetylene black, and ketjen black, metals, and conductive ceramics. Examples of the shape of the conductive agent include powder and fiber.

  As a minimum of content of a conductive agent in cathode active material layer 8, 0.1 mass% is preferred and 0.5 mass% is more preferred. On the other hand, as an upper limit of content of a electrically conductive agent, 10 mass% is preferable and 5 mass% is more preferable. By setting the content of the conductive agent in the above range, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  Examples of the binder include thermoplastic resins such as fluorine resin (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), polyethylene, polypropylene, polyimide, ethylene-propylene-diene rubber (EPDM), and sulfonated EPDM. , Styrene butadiene rubber (SBR), elastomers such as fluorine rubber, polysaccharide polymers, and the like.

  As a minimum of content of the binder in the positive electrode active material layer 8, 1 mass% is preferable and 2 mass% is more preferable. On the other hand, the upper limit of the binder content is preferably 10% by mass, and more preferably 5% by mass. By setting the binder content in the above range, the positive electrode active material can be stably held.

  Examples of the thickener include polysaccharide polymers such as carboxymethylcellulose (CMC) and methylcellulose. When the thickener has a functional group that reacts with lithium, it is preferable to deactivate this functional group in advance by methylation or the like.

  The filler is not particularly limited as long as it does not adversely affect battery performance. Examples of the main component of the filler include polyolefins such as polypropylene and polyethylene, silica, alumina, zeolite, glass, and carbon.

  As a minimum of average thickness of positive electrode active material layer 8, 10 micrometers is preferred and 20 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the positive electrode active material layer 8 is preferably 100 μm, and more preferably 80 μm. By setting the average thickness of the positive electrode active material layer 8 to the above lower limit or more, the positive electrode reaction can be sufficiently activated. In addition, by setting the average thickness of the positive electrode active material layer 8 to be equal to or less than the above upper limit, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  The negative electrode current collector 10 of the negative electrode plate 3 can have the same configuration as the positive electrode current collector 7 described above, but the material is preferably copper or a copper alloy. That is, the negative electrode current collector 10 of the negative electrode plate 3 is preferably a copper foil. Examples of the copper foil include rolled copper foil and electrolytic copper foil.

  The negative electrode active material layer 11 is formed from a so-called negative electrode plate mixture containing a negative electrode active material. Moreover, the negative electrode plate mixture forming the negative electrode active material layer 11 includes optional components such as a conductive agent, a binder, a thickener, and a filler as necessary. The same components as those of the positive electrode active material layer 8 can be used as optional components such as a conductive agent, a binder, a thickener, and a filler.

  As the negative electrode active material, a material capable of inserting and extracting lithium ions is preferably used. Specific examples of the negative electrode active material include metals such as lithium and lithium alloys, metal oxides, polyphosphate compounds such as carbon materials such as graphite and amorphous carbon (easily graphitizable carbon or non-graphitizable carbon). Is mentioned.

  Among the negative electrode active materials, Si, Si oxide, Sn, Sn oxide, or a combination thereof is used from the viewpoint of setting the discharge capacity per unit facing area between the positive electrode plate 2 and the negative electrode plate 3 to a suitable range. It is preferable to use Si oxide. Si and Sn can have a discharge capacity about three times that of graphite when they are made into oxides.

When Si oxide is used as the negative electrode active material, the ratio of the number of atoms of O to Si contained in the Si oxide is preferably more than 0 and less than 2. That is, as the Si oxide, a compound represented by SiO _x (0 <x <2) is preferable. The ratio of the number of atoms is more preferably 0.5 or more and 1.5 or less.

  As the negative electrode active material, those described above may be used singly or in combination of two or more. For example, by using a mixture of Si oxide and another negative electrode active material, the discharge capacity per unit facing area between the positive electrode plate 2 and the negative electrode plate 3 and the mass of the negative electrode active material to be described later can be reduced. Both mass ratios can be adjusted to be suitable values. Other negative electrode active materials used in combination with Si oxide include carbon materials such as graphite, hard carbon, soft carbon, coke, acetylene black, ketjen black, vapor grown carbon fiber, fullerene, activated carbon and the like. . Only one kind of these carbon materials may be mixed with Si oxide, or two or more kinds may be mixed with Si oxide in an arbitrary combination and ratio. Among these other negative electrode active materials, graphite having a relatively low charge / discharge potential is preferable, and a secondary battery element having a high energy density can be obtained by using graphite. Examples of graphite used by mixing with Si oxide include flaky graphite, spherical graphite, artificial graphite, and natural graphite. Among these, scaly graphite that can easily maintain contact with the surface of the Si oxide particles even after repeated charge and discharge is preferable.

  Furthermore, the negative electrode active material layer 11 includes a small amount of typical nonmetallic elements such as B, N, P, F, Cl, Br, and I, Li, Na, Mg, Al, K, Ca, Zn in addition to Si oxide. Typical metal elements such as Ga, Ge, and transition metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, and W may be contained. .

As the Si oxide (substance represented by the general formula SiO _x ), it is preferable to use a material containing both phases of SiO ₂ and Si. Such Si oxide has a small volume change and excellent charge / discharge cycle characteristics because lithium is occluded and released from Si in the SiO ₂ matrix.

  The average particle size of the Si oxide is preferably 1 μm or more and 15 μm or less. By setting the average particle diameter of the Si oxide to be equal to or less than the above upper limit, the charge / discharge cycle characteristics of the subunit S and, consequently, the laminated electrode body B can be improved.

  The Si oxide can be used from highly crystalline to amorphous. Further, as the Si oxide, one washed with an acid such as hydrogen fluoride or sulfuric acid or one reduced with hydrogen may be used.

  As a minimum of content of Si oxide in a negative electrode active material, 30 mass% is preferred, 50 mass% is more preferred, and 70 mass% is still more preferred. On the other hand, the upper limit of the content of Si oxide is usually 100% by mass, and preferably 90% by mass.

  As a minimum of content of the negative electrode active material in the negative electrode active material layer 11, 60 mass% is preferable, 80 mass% is more preferable, 90 mass% is further more preferable. On the other hand, as an upper limit of content of a negative electrode active material, 99 mass% is preferable and 98 mass% is more preferable. By setting the content of the negative electrode active material particles in the above range, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  As a minimum of content of the binder in the negative electrode active material layer 11, 1 mass% is preferable and 5 mass% is more preferable. On the other hand, the upper limit of the binder content is preferably 20% by mass, and more preferably 15% by mass. By setting the binder content in the above range, the negative electrode active material can be stably held.

  As a minimum of average thickness of negative electrode active material layer 11, 10 micrometers is preferred and 20 micrometers is more preferred. Conversely, the upper limit of the average thickness of the negative electrode active material layer 11 is preferably 100 μm and more preferably 80 μm. By making the average thickness of the negative electrode active material layer 11 equal to or more than the lower limit, the negative electrode reaction can be sufficiently activated. In addition, by setting the average thickness of the negative electrode active material layer 11 to be equal to or less than the above upper limit, the energy density of the subunit S and thus the laminated electrode body B can be increased.

  The electrode unit forming step in the method for manufacturing the laminated electrode body includes a step of laminating a plurality of subunits S (subunit laminating step), and from the end portions of the positive electrode plate 2 and the negative electrode plate 3 of each of the laminated subunits S. A step of welding the protruding separators 1 (welding step). The electrode unit forming step includes a step of trimming outer portions of the plurality of separators 1 that are welded (trimming step), and a step of bending the welded portions of the plurality of separators 1 along the side edges of the positive electrode plate 2 and the negative electrode plate 3. (Bending step) may be further provided.

  In the subunit stacking step, a plurality of subunits S are oriented and stacked in the same direction. Thereby, the some positive electrode plate 2 and the some negative electrode plate 3 are arrange | positioned alternately via the separator 1, and the laminated body by which the separator 1 is arrange | positioned further outside the outermost positive electrode plate 2 is formed.

  The plurality of subunits S are stacked by, for example, using a guide that contacts the four outer edges of the separator 1 and the like. By stacking S, it can be performed relatively quickly and accurately.

  The number of subunits S to be stacked can be, for example, 5 or more and 15 or less. By setting the number of stacked subunits S within this range, the distance between the outer separators 1 does not become too large. As a result, the separators protrude from the ends of the positive electrode plate 2 and the negative electrode plate 3 of each subunit S. Even if the length of 1 is reduced, the end portions of the separator 1 can be bundled and welded together to integrate the plurality of subunits S, so that the amount of separator 1 used can be reduced.

  In the welding step, the end portions of all the separators 1 are bundled so as to be in close contact with each other and welded. Specifically, the oxidation resistant layer 5 of the separator 1 is broken and the resin layers 4 are welded together. For this reason, it is preferable to perform the welding of the separator 1 using an ultrasonic vibration indenter (horn). Also, as the ultrasonic vibration indenter, for example, a resin having a contact surface on which a large number of fine protrusions are formed is used to destroy the oxidation resistant layer 5 and scrape the fragments of the oxidation resistant layer 5. The layers 4 can be efficiently welded together.

  In the trimming step, the portions protruding outside the welding regions R1, R2 of the separator 1 are cut off. The separator 1 is designed to have a minimum size capable of forming the welding regions R1 and R2. As shown in FIG. 3, the two separators 1 are bundled so as to be in close contact with each other in the welding process. In addition, since the end portions of the separator 1 are displaced stepwise due to the thicknesses of the positive electrode plate 2 and the negative electrode plate 3, the separator 1 is disposed outside the welding regions R1 and R2 formed in the portion where all the separators 1 are stacked. Will protrude. Therefore, in this trimming step, the portions protruding in a stepped manner outside the welding regions R1, R2 are mainly cut out. Thereby, when the laminated electrode body B is formed, the dead space occupied by the separators 1 outside the welding regions R1, R2 can be reduced, and the energy density of the laminated electrode body B can be increased.

  In the bending step, portions of the separator 1 that protrude from the positive electrode plate 2 and the negative electrode plate 3 are bent along the side edges of the positive electrode plate 2 and the negative electrode plate 3. Thereby, when the laminated electrode body B is formed, the dead space occupied by the portions protruding from the positive electrode plate 2 and the negative electrode plate 3 of the separator 1 can be reduced, and the energy density of the laminated electrode body B can be increased.

  The integration step in the method for manufacturing the laminated electrode body includes a step of laminating a plurality of electrode units U (electrode unit laminating step) and a step of disposing one negative electrode plate 3 on the separator 1 disposed in the outermost layer ( Negative electrode plate disposing step) and a step of heating and pressurizing the electrode unit U and the negative electrode plate 3 in a stacked state (electrode body heating and pressurizing step). Further, this integration step further includes a step of covering the outer periphery of the laminate of the plurality of electrode units U and the negative electrode plate 3 with the resin film 13 (resin film wrapping step) before the electrode body heating and pressing step. Is preferred.

  In the electrode unit lamination step, the plurality of electrode units U are oriented and laminated in the same direction. That is, between two adjacent electrode units U, the separator 1 of the other electrode unit U contacts the negative electrode plate 3 of one electrode unit U. Thereby, the laminated body in which the some positive electrode plate 2 and the negative electrode plate 3 were laminated | stacked via the separator 1 is formed.

  In the negative electrode plate arranging step, a further negative electrode plate 3 is laminated on the outer side of the separator 1 arranged on the outermost layer, whereby the negative electrode plate 3 is arranged on both outer sides, and the plurality of positive electrode plates 2 and negative electrode plates 3 are separated from each other. 1 to form a laminated body alternately laminated.

  Note that “arranging one negative electrode plate on the separator” is not intended to limit the vertical relationship between the plurality of electrode units U and the further negative electrode plate 3, and the two electrodes stacked on the outermost side. A further negative electrode plate 3 is laminated on the outer side of the separator 1 on the side opposite to the negative electrode plate 3 of the electrode unit U that is in contact with the separator 1 of the electrode unit U adjacent to the unit U. means. Therefore, the single negative electrode plate 3 may be disposed first, and a plurality of electrode units may be stacked thereon.

  In the resin film wrapping step, the plurality of electrode units U and the negative electrode plate 3 are covered with the resin film 13 to cover the plurality of electrode units U and the negative electrode plate 3 in the next electrode body heating and pressing step. Hold it so that it is not misaligned.

  In this way, the resin film 13 prevents the displacement of the separator 1, the positive electrode plate 2, and the negative electrode plate 3 in the electrode body heating and pressing step, thereby reducing the margin for the displacement of the positive electrode plate 2 and the negative electrode plate 3. The opposing area of the positive electrode plate 2 and the negative electrode plate 3 can be increased, and the energy density of the laminated electrode body B can be further improved.

  Moreover, the resin film 13 which covers the laminated body of the several electrode unit U and the negative electrode plate 3 can protect the negative electrode plate 3 of both outer sides, and can make especially easy manufacture of the electrical storage element mentioned later.

  Examples of the main component of the resin film 13 include polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). Especially, as a main component of the resin film 13, the polypropylene with favorable heat-sealing property is especially suitable.

  As a minimum of average thickness of resin film 13, 20 micrometers is preferred and 50 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the resin film 13 is preferably 150 μm, and more preferably 100 μm. By setting the average thickness of the resin film 13 to be equal to or greater than the above lower limit, it is possible to prevent the displacement of the plurality of electrode units U and the negative electrode plate 3 and to protect the negative electrode plate 3 without breaking. Moreover, since the laminated body of the several electrode unit U and the negative electrode plate 3 can be tightly coat | covered tightly without gap by making the average thickness of the resin film 13 below the said upper limit, the electrode unit U and the negative electrode plate 3 can be ensured, and contributes to an improvement in the energy density of the laminated electrode body B.

  In the electrode body heating and pressing step, the outermost electrodes between adjacent subunits S and the outermost electrodes are preferably heated and pressed by heating and pressing a laminated body of a plurality of electrode units U and one negative electrode plate 3 covered with the resin film 13. The separator 1 outside the unit U and the negative electrode plate 3 are joined. Thereby, the laminated electrode body B in which all the separators 1, the positive electrode plate 2, and the negative electrode plate 3 are bonded and fixed to each other is obtained.

  The method for manufacturing a storage element according to an embodiment of the present invention is a process of storing the stacked electrode body B obtained by the above-described stacked electrode body manufacturing method in the case 14 as shown in FIG. 7 (laminated electrode body storing process). And a step of filling the case 14 with an electrolytic solution (electrolytic solution filling step).

  The case 14 includes a bottomed square cylindrical case body 15 and a plate-like lid body 16 that seals the opening of the case body 15. The storage element shown in FIG. 7 is attached to the positive electrode external terminal 17 and the negative electrode external terminal 18 provided so as to penetrate the lid body 16, and the positive electrode external terminal 17 and the negative electrode external terminal 18 inside the case 14. A positive electrode connecting member 19 and a negative electrode connecting member 20 to which the positive electrode tab 9 and the negative electrode tab 12 are connected.

  The case 14 is a sealed container that houses the laminated electrode body B and in which an electrolytic solution is enclosed.

  The material of the case 14 may be, for example, a resin or the like as long as it has a sealing property that can enclose an electrolytic solution and a strength that can protect the laminated electrode body B, but a metal is preferably used. In other words, the case 14 may be a flexible bag formed from a laminate film, for example, but it is preferable to use a rigid metal case that can more reliably protect the laminated electrode body B.

As the electrolytic solution enclosed in the case 14 together with the laminated electrode body B, a known electrolytic solution that is usually used for the electric storage element can be used. For example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. A solution in which lithium hexafluorophosphate (LiPF ₆ ) or the like is dissolved in a cyclic carbonate or a solvent containing a chain carbonate such as diethyl carbonate (DEC), dimethyl carbonate (DMC), or ethyl methyl carbonate (EMC). Can do.

  In the laminated electrode body accommodation step, the positive electrode tab 9 and the negative electrode tab 12 are connected to the positive electrode connecting member 19 and the negative electrode connecting member 20, respectively, and then the laminated electrode body B is inserted into the case body 15 and The opening of the main body 15 is sealed.

  As a method for connecting the positive electrode tab 9 and the negative electrode tab 12 to the positive electrode connecting member 19 and the negative electrode connecting member 20, for example, ultrasonic welding, laser welding, caulking, or the like can be employed.

  In the electrolytic solution filling step, an electrolytic solution is injected into the case 14. For this reason, it is preferable that the case 14 is formed with a sealable inlet.

  According to the method for manufacturing a storage element, the stacked electrode body B having a large energy density is efficiently manufactured by the above-described manufacturing method of the stacked electrode body, and the storage element is manufactured using the stacked electrode body B. Can be manufactured efficiently.

  The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, the components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.

  In the manufacturing method of the laminated electrode body, an electrode unit in which separators of a plurality of subunits are welded is not formed, but a plurality of subunits are laminated, and a further negative electrode plate is laminated on the outermost separator of the laminated body of subunits. The laminated electrode body may be formed by heating and pressurizing the resulting product.

  In the method for manufacturing the laminated electrode body, a laminated electrode body may be produced by heating and pressing a laminated body in which a negative electrode plate is laminated on one electrode unit.

  The method for manufacturing a laminated electrode body and the method for manufacturing a power storage element according to the present invention can be used for manufacturing various power storage elements, and in particular, the power of a vehicle such as an electric vehicle or a plug-in hybrid electric vehicle (PHEV). It is suitably used for producing a secondary battery used as a source.

DESCRIPTION OF SYMBOLS 1 Separator 2 Positive electrode plate 3 Negative electrode plate 4 Resin layer 5 Oxidation resistant layer 6 Adhesive layer 7 Positive electrode current collector 8 Positive electrode active material layer 9 Positive electrode tab 10 Negative electrode current collector 11 Negative electrode active material layer 12 Negative electrode tab 13 Resin film 14 Case 15 Case body 16 Lid 17 Positive external terminal 18 Negative external terminal 19 Positive connection member 20 Negative connection member B Multilayer electrode body C Cutter H Plate heater P Pressure roller S Sub unit U Electrode unit

Claims (5)

Disposing one positive electrode plate between two separators having adhesive layers on both sides and disposing one negative electrode plate on one of the two separators;
Heating and pressing in a state where one of the one negative electrode plate, one of the two separators, the other one of the positive electrode plate and the two separators are laminated,
In order to obtain a subunit that integrates one of the one negative electrode plate, one of the two separators, the one positive electrode plate, and the other of the two separators, both end portions of the two separators are Cutting the two separators so as to protrude from the end portions of the positive electrode plate and the negative electrode plate, respectively. Laminating a plurality of the subunits;
Welding the separators protruding from the ends of the positive plate and the negative plate of each of the plurality of subunits to obtain an electrode unit in which the plurality of stacked subunits are integrated. 2. A method for producing a laminated electrode body according to 1. Laminating a plurality of the electrode units;
Disposing one negative electrode plate on the separator disposed on the outermost layer;
The method for producing a laminated electrode body according to claim 2, further comprising heating and pressing in a state where the plurality of electrode units and the negative electrode plate are laminated.   The laminated electrode body according to claim 3, further comprising covering an outer periphery of a laminate of the plurality of electrode units and the negative electrode plate with a resin film before heating and pressurizing the plurality of electrode units and the negative electrode plate. Production method. A laminated electrode body obtained by the production method according to any one of claims 1 to 4, is housed in a case.

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