Method and device for manufacturing lithium ion secondary battery electrode

Abstract

To stably form an electrode composition layer with a uniform thickness even if a supply situation of an electrode composition changes, when the electrode composition is coated on a predetermined area to be formed using a powder feeder.SOLUTION: A device for manufacturing a lithium ion secondary battery electrode includes: a powder feeder 30 to feed an electrode composition; a control section 40 to control a residual amount of the electrode composition in the powder feeder 30; an alarm section 50 to issue a predetermined alarm; an adhesion suppression section 60 to suppress adhesion of the electrode composition; an automatic supply section 70 to supply the electrode composition to the powder feeder 30; a conveying section 80 to convey a base material 100; and a pressurizing section 90 to pressurize the electrode composition supplied on the base material 100.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for manufacturing electrodes for lithium ion secondary batteries. [Background technology]

[0002] Recently, lithium ion secondary batteries have been attracting attention as high-capacity, small, and lightweight batteries. A typical lithium ion battery is configured by stacking a plurality of unit cells, each of which is made up of a laminate of a positive electrode collector, a positive electrode active material layer, a separator, a negative electrode collector, and a negative electrode active material layer, to form a battery pack, and then sealing the battery pack with a battery exterior material, as in Patent Document 1, for example. In a lithium ion secondary battery, a positive electrode is configured by the positive electrode collector and the positive electrode active material layer, and a negative electrode is configured by the negative electrode collector and the negative electrode active material layer, and these are used as electrodes.

[0003] A method is known for manufacturing an electrode for a lithium ion secondary battery, in which a powder feeder for an electrode composition containing an electrode active material is used to supply the electrode composition from the powder feeder to an area on a substrate where an electrode composition layer is to be formed, thereby forming an electrode composition layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6154369 [Patent Document 2] Patent Publication No. 2022-023365 [Patent Document 3] Patent Publication No. 2021-023473 Summary of the Invention [Problem to be solved by the invention]

[0005] By using the powder feeder as described above, it is possible to coat the electrode composition so as to appropriately fill a predetermined region defined on the substrate, for example, a recess set in a region where an electrode composition layer is to be formed. However, when coating the electrode composition, the supply state of the electrode composition changes depending on the powder properties of the electrode composition to be supplied, coating conditions, etc., making it difficult to adjust the coating, and there is a problem that the thickness of the electrode composition layer cannot be maintained uniform.

[0006] The present invention aims to provide an electrode manufacturing apparatus and method that can stably form an electrode composition layer of uniform thickness even when the supply conditions of the electrode composition change when applying the electrode composition to a specified planned formation area using a powder feeder. [Means for solving the problem]

[0007] As a result of extensive research based on the above findings, the present inventors have arrived at the following aspects of the invention. a powder feeder that supplies an electrode composition including an electrode active material onto a substrate; a control unit that defines an allowable value for a remaining amount of the electrode composition in the powder feeder and controls the remaining amount in relation to the allowable value; having Manufacturing equipment for electrodes for lithium-ion secondary batteries.

[0008] A method for producing an electrode for a lithium ion secondary battery, comprising forming an electrode composition layer made of an electrode composition containing an electrode active material on a substrate, a tolerance for a remaining amount of the electrode composition in a powder feeder is defined, and the electrode composition in the powder feeder is supplied onto the substrate while controlling the remaining amount in relation to the tolerance. A method for manufacturing electrodes for lithium-ion secondary batteries. Effect of the Invention

[0009] According to the manufacturing apparatus and method for electrodes for lithium ion secondary batteries of the present invention, when applying an electrode composition to a predetermined planned formation area using a powder feeder, an electrode composition layer having a uniform thickness can be stably formed even if the supply conditions of the electrode composition change. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing a secondary battery module according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing a schematic configuration of an apparatus for manufacturing an electrode for a lithium ion secondary battery according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a flow chart showing the steps of a method for producing an electrode for a lithium ion secondary battery according to the present embodiment. [Figure 4] 5A to 5C are schematic diagrams illustrating an example of a frame member arrangement step in the manufacturing method of an electrode for a lithium ion secondary battery according to the present embodiment. [Diagram 5] 3 is a schematic diagram showing an example of a mask layer used in a masking step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. FIG. [Figure 6] 5A to 5C are schematic diagrams showing an example of a masking step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. [Figure 7] 5A to 5C are schematic diagrams showing other examples of mask layers used in the masking step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. [Figure 8] 5A to 5C are schematic diagrams illustrating an example of a supplying step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. [Figure 9] 5A to 5C are schematic diagrams illustrating an example of a mask removing step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. [Figure 10] 5A to 5C are schematic diagrams illustrating an example of a pressurizing step in the method for producing an electrode for a lithium ion secondary battery according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, specific embodiments of the method for producing an electrode for a lithium ion secondary battery according to the present invention will be described in detail with reference to the drawings.

[0012] (Structure of lithium-ion secondary battery) In describing the present embodiment, first, the configuration of a secondary battery module of a lithium ion secondary battery including electrodes manufactured according to the present embodiment will be described. Fig. 1 is a schematic cross-sectional view showing a secondary battery module according to a first embodiment.

[0013] The secondary battery module 1 is configured as a battery cell 20 consisting of a flat-plate laminated battery (single cell) in which a negative electrode 2 consisting of a negative electrode current collector 11 and a negative electrode active material layer 12 and a positive electrode 3 consisting of a positive electrode active material layer 14 and a positive electrode current collector 15 are laminated via a separator 13. That is, the battery cell 20 constituting the secondary battery module 1 is formed in a substantially rectangular flat plate shape as a whole by stacking the negative electrode current collector 11, the negative electrode active material layer 12, the separator 13, the positive electrode active material layer 14, and the positive electrode current collector 15 in an upward direction.

[0014] The secondary battery module 1 further includes a frame-shaped seal material 9 disposed on the periphery of the battery cell 20. The seal material 9 supports the separator 13 by embedding the end of the separator 13, and the seal material 9 fixes the positive electrode current collector 15 and the negative electrode current collector 11 to the upper and lower surfaces of the seal material 9 in surface contact with each other. The peripheral portions of the negative electrode current collector 11, the positive electrode current collector 15, and the separator 13 are fixed via the seal material 9, so that the negative electrode active material layer 12 and the positive electrode active material layer 14 can be tightly sealed without leaking to the outside. The seal material 9 can also determine the positional relationship between the negative electrode current collector 11, the separator 13, and the positive electrode current collector 15. The gap between the negative electrode current collector 11 and the separator 13, and the gap between the separator 13 and the positive electrode current collector 15 are adjusted in advance according to the capacity of the battery, and the negative electrode current collector 11, the separator 13, and the positive electrode current collector 15 can be fixed using the sealing material 9 so as to maintain this adjusted gap.

[0015] A negative electrode-side current supply layer 10 as a conductive layer is laminated in a planar shape on the lower side of the negative electrode current collector 11, and a positive electrode-side current extraction layer 16 as a conductive layer is laminated in a planar shape on the upper side of the positive electrode current collector 15. Conductive parts 7 and 8, which are locations to which current is supplied, are formed on the negative electrode-side current supply layer 10 and the positive electrode-side current extraction layer 16, respectively.

[0016] The secondary battery module 1 may be provided with an exterior film (not shown) that covers the battery cells 20, the negative electrode-side current supply layer 10, and the positive electrode-side current extraction layer 16. The exterior film may be made of, for example, an insulating material, and may be made of a known material used in batteries, and is preferably a laminate film. As the laminate film, a three-layer laminate film having a nylon film on the outside, an aluminum foil in the center, and an adhesive layer such as modified polypropylene on the inside can be preferably used.

[0017] The secondary battery module 1 to which the present invention is applied is not limited to the case where the battery cells 20 of the lithium ion secondary battery are constituted by single cells. For example, a plurality of battery cells 20 may be stacked and connected to form an assembled battery.

[0018] In such a battery pack, a plurality of battery cells 20 may be connected in series to freely supply current via the conductive part 8 connected to the positive electrode side current extraction layer 16 of the uppermost battery cell 20 and the conductive part 7 connected to the negative electrode side current supply layer 10 of the lowermost battery cell 20. In such a case, the battery cells 20 are stacked so that the lower surface of the negative electrode side current supply layer 10 and the upper surface of the positive electrode side current extraction layer 16 of the battery cells 20 to be connected to each other are adjacent to each other. Furthermore, when forming such a battery pack, a plurality of battery cells 20 may be connected in parallel, or a combination of series connection and parallel connection may be used. By forming such a battery pack, a high capacity and a high output can be obtained. In addition, a current may be freely supplied independently from the conductive parts 7 and 8 connected to the negative electrode side current supply layer 10 and the positive electrode side current extraction layer 16 of each battery cell 20, respectively.

[0019] Preferred embodiments of each of the constituent materials that make up the battery cell 20 will be described below.

[0020] The positive electrode active material layer contains a positive electrode active material as an electrode composition. The positive electrode active material is a composite oxide of lithium and a transition metal {a composite oxide containing one type of transition metal element (LiCoO 2 , LiNiO 2 , LiAlMnO 4 , LiMnO 2 and LiMn 2 O 4 etc.), and composite oxides containing two transition metal elements (e.g. LiFeMnO 4 , LiNi 1-x Co x O 2 , LiMn 1-y Co y O 2 , LiNi 1 / 3 Co 1 / 3 Al 1 / 3 O 2 and LiNi 0.8 Co 0.15 Al 0.05 O 2 ) and composite oxides containing three or more transition metal elements [e.g. LiM a M' b M" c O 2 (M, M' and M" are different transition metal elements and satisfy a+b+c=1. For example, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 ) etc.}, lithium-containing transition metal phosphates (e.g., LiFePO 4 , LiCoPO 4 , LiMnPO 4 and LiNiPO 4 ), transition metal oxides (e.g. MnO 2 and V 2 O 5 ), transition metal sulfides (e.g., MoS 2 and TiS 2) and conductive polymers (for example, polyaniline, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polyvinylcarbazole), and the like, and two or more of them may be used in combination. The lithium-containing transition metal phosphate may have some of the transition metal sites substituted with other transition metals.

[0021] In this embodiment, the positive electrode active material is preferably a coated positive electrode active material coated with a conductive assistant and a coating resin. When the positive electrode active material is covered with a coating resin, the volume change of the electrode is mitigated, and the expansion of the electrode can be suppressed.

[0022] Examples of the conductive additive include metal-based conductive additives [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon-based conductive additives [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.)], and mixtures thereof. These conductive assistants may be used alone or in combination of two or more kinds, and may also be used as alloys or metal oxides thereof.

[0023] Among these, from the viewpoint of electrical stability, aluminum, stainless steel, silver, gold, copper, titanium, carbon-based conductive assistants, and mixtures thereof are more preferable, silver, gold, aluminum, stainless steel, and carbon-based conductive assistants are even more preferable, and carbon-based conductive assistants are particularly preferable. Furthermore, these conductive assistants may be obtained by coating the particle-based ceramic material or resin material with a conductive material (preferably a metal one of the conductive assistants described above) by plating or the like.

[0024] The shape (form) of the conductive additive is not limited to a particulate form, and may be a form other than a particulate form, and may be a form that is in practical use as a so-called filler-based conductive additive, such as carbon nanofibers or carbon nanotubes.

[0025] The ratio of the coating resin to the conductive assistant is not particularly limited, but from the viewpoint of the internal resistance of the battery, etc., the weight ratio of the coating resin (resin solid content weight):conductive assistant is preferably 1:0.01 to 1:50, and more preferably 1:0.2 to 1:3.0.

[0026] As the coating resin, for example, a non-aqueous secondary battery active material coating resin obtained by polymerizing a monomer composition containing at least one crosslinking agent (b) selected from the group consisting of an ester compound (a11) of a monohydric aliphatic alcohol having 4 to 12 carbon atoms and (meth)acrylic acid, (meth)acrylic acid (a12), a compound (b1) having two or more groups capable of reacting with the carboxyl group of (meth)acrylic acid (a12), a compound (b2) having two or more radically polymerizable groups, and a compound (b3) having one or more groups capable of reacting with the carboxyl group of (meth)acrylic acid (a12) and one or more radically polymerizable groups, can be suitably used. In this non-aqueous secondary battery active material coating resin, the weight ratio of the ester compound (a11) to the (meth)acrylic acid (a12) [ester compound (a11) / (meth)acrylic acid (a12)] is preferably 10 / 90 to 90 / 10.

[0027] The positive electrode active material layer may contain a conductive assistant other than the conductive assistant contained in the coated positive electrode active material. As the conductive assistant, the same conductive assistant as that contained in the coated positive electrode active material described above can be suitably used.

[0028] The positive electrode active material layer preferably contains a positive electrode active material and is a non-binding material that does not contain a binder that binds the positive electrode active material together. Here, non-bound material means that the positive electrode active material is not fixed in position by a binding material (also called a binder), and the positive electrode active materials are not irreversibly fixed to each other or to the current collector.

[0029] The positive electrode active material layer may contain an adhesive resin. As the adhesive resin, for example, a resin in which a small amount of an organic solvent is mixed with a non-aqueous secondary battery active material coating resin described in JP 2017-54703 A to adjust its glass transition temperature to room temperature or lower, and a resin described as an adhesive in JP 10-255805 A can be suitably used.

[0030] The adhesive resin refers to a resin that does not solidify even when the solvent component is evaporated and dried, and has adhesiveness (the property of adhering by applying slight pressure without using water, solvent, heat, etc.) On the other hand, the solution-drying type electrode binder used as a binding material refers to a material that dries and solidifies by evaporating the solvent component, thereby firmly adhering and fixing active materials together. Therefore, the solution drying type electrode binder (binding material) and the adhesive resin are different materials.

[0031] The thickness of the positive electrode active material layer is not particularly limited, but from the viewpoint of battery performance, it is preferably 250 μm to 600 μm, and more preferably 350 μm to 500 μm.

[0032] The negative electrode active material layer contains a negative electrode active material as an electrode composition. As the negative electrode active material, known negative electrode active materials for lithium ion batteries can be used, and examples of the negative electrode active material include carbon-based materials [graphite, non-graphitizable carbon, amorphous carbon, resin baked bodies (e.g., phenolic resins and furan resins baked and carbonized, etc.), cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), and carbon fibers, etc.], silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composites (carbon particles whose surfaces are coated with silicon and / or silicon carbide, silicon particles or silicon oxide particles whose surfaces are coated with carbon and / or silicon carbide, silicon carbide, etc.)], and silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composites (carbon particles whose surfaces are coated with silicon and / or silicon carbide, silicon particles or silicon oxide particles whose surfaces are coated with carbon and / or silicon carbide, silicon carbide, etc.], and silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composites (carbon particles whose surfaces are coated with silicon and / or silicon carbide, silicon carbide, etc.)] ... oxide (SiOx), silicon oxide (SiOx), silicon oxide Examples of the conductive material include silicon alloys (silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon-manganese alloy, silicon-copper alloy, silicon-tin alloy, etc.), conductive polymers (for example, polyacetylene and polypyrrole), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxide, etc.) and metal alloys (for example, lithium-tin alloy, lithium-aluminum alloy, lithium-aluminum-manganese alloy, etc.), and mixtures of these with carbon-based materials.

[0033] In this embodiment, the negative electrode active material is preferably a coated negative electrode active material coated with a conductive assistant and a coating resin similar to the coated positive electrode active material described above. As the conductive assistant and the coating resin, the same conductive assistant and coating resin as those in the coated positive electrode active material described above can be suitably used.

[0034] The negative electrode active material layer may contain a conductive assistant other than the conductive assistant contained in the coated negative electrode active material. As the conductive assistant, the same conductive assistant as the conductive assistant contained in the coated positive electrode active material described above can be suitably used.

[0035] The negative electrode active material layer is preferably a non-binding material that does not contain a binder that binds the negative electrode active materials together, similar to the positive electrode active material layer, and may contain an adhesive resin, similar to the positive electrode active material layer.

[0036] The thickness of the negative electrode active material layer is not particularly limited, but from the viewpoint of battery performance, it is preferably 380 μm to 780 μm, and more preferably 480 μm to 680 μm.

[0037] The positive electrode current collector and the negative electrode current collector may be metal current collectors, but are preferably flexible resin current collectors made of, for example, a conductive polymer material. The shape of the resin collector is not particularly limited, and may be a sheet-like collector made of a conductive polymer material, or a deposition layer made of fine particles made of a conductive polymer material. The thickness of the resin current collector is not particularly limited, but is preferably 50 μm to 500 μm.

[0038] The conductive polymer material constituting the resin collector may be, for example, a conductive polymer or a resin to which a conductive agent has been added as necessary. As the conductive agent constituting the conductive polymer material, the same conductive assistant as that contained in the coated positive electrode active material described above can be suitably used.

[0039] Examples of resins that constitute the conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyethernitrile (PEN), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, and mixtures thereof. From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferred, and polyethylene (PE), polypropylene (PP) and polymethylpentene (PMP) are more preferred.

[0040] Examples of the separator include known separators for lithium ion batteries, such as porous films made of polyethylene or polypropylene, laminated films of porous polyethylene film and porous polypropylene, nonwoven fabrics made of synthetic fibers (polyester fibers, aramid fibers, etc.) or glass fibers, and those having ceramic particles such as silica, alumina, titania, etc. attached to their surfaces.

[0041] In this embodiment, the electrode composition may be a so-called wet powder containing an electrode active material and an electrolyte for the positive electrode active material layer and the negative electrode active material layer. Instead of a wet powder using a liquid electrolyte, it is also possible to use a so-called dry powder containing, for example, an electrode active material and a solid electrolyte. In this case, a separator is not required in the battery cell 20.

[0042] As the electrolytic solution, a known electrolytic solution containing an electrolyte and a non-aqueous solvent, which is used in the production of known lithium ion batteries, can be used. As the electrolyte, a substance used in a known electrolytic solution can be used, for example, LiN(FSO 2 ) 2 , LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 and LiClO 4 Lithium salts of inorganic acids such as LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 and LiC(CF 3 SO 2 ) 3 Among these, the imide-based electrolyte [LiN(FSO 2 ) 2 , LiN(CF 3 SO 2 ) 2 and LiN(C 2 F 5SO 2 ) 2 etc.] and LiPF 6 It is.

[0043] As the non-aqueous solvent, those used in known electrolytic solutions can be used, such as lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphates, nitrile compounds, amide compounds, sulfones, sulfolane, and mixtures thereof.

[0044] The electrolyte concentration of the electrolytic solution is preferably 15 mol / L to 5 mol / L, more preferably 1.5 mol / L to 4 mol / L, and further preferably 2 mol / L to 3 mol / L. If the electrolyte concentration of the electrolytic solution is less than 1 mol / L, the battery may not exhibit sufficient input / output characteristics, whereas if it exceeds 5 mol / L, the electrolyte may precipitate. The electrolyte concentration of the electrolytic solution can be confirmed by extracting the electrolytic solution constituting the lithium ion battery electrode or the lithium ion battery without using a solvent or the like and measuring the concentration.

[0045] [Electrode manufacturing equipment] An apparatus for manufacturing electrodes for lithium ion secondary batteries will be described below. FIG. 2 is a schematic diagram showing a schematic configuration of a manufacturing apparatus for an electrode for a lithium ion secondary battery according to this embodiment.

[0046] The electrode manufacturing apparatus of this embodiment includes a powder feeder 30 for the electrode composition, a control unit 40 for controlling the remaining amount of electrode composition in the powder feeder 30, an alarm unit 50 for issuing a predetermined alarm, an adhesion prevention unit 60 for preventing adhesion of the electrode composition, an automatic supply unit 70 for supplying the electrode composition to the powder feeder 30, a transport unit 80 for transporting the substrate 100, and a pressurizing mechanism 90 for the electrode composition supplied onto the substrate 100.

[0047] The powder feeder 30 supplies a powdered electrode composition 120 containing the above-mentioned electrode active material, and supplies the electrode composition 120 stored in the powder feeder 30 to a predetermined location on the substrate 100.

[0048] The control unit 40 defines an allowable value for the remaining amount of the electrode composition in the powder feeder 30, and controls the remaining amount of the electrode composition in relation to the allowable value. The discharge amount (discharge speed) of the electrode composition from the powder feeder 30 varies depending on the powder properties, coating conditions, etc. For example, if the remaining amount of the electrode composition in the powder feeder 30 is small, the discharge amount (discharge speed) of the electrode composition from the powder feeder 30 will vary. Even if the remaining amount of the electrode composition in the powder feeder 30 is large, the discharge amount (discharge speed) of the electrode composition from the powder feeder 30 will vary due to the electrode composition being compressed and compacted by its own weight in the powder feeder 30. The control unit 40 specifies an allowable range as an allowable value of the remaining amount of the electrode composition in the powder feeder 30 at which the uniform fluidity of the electrode composition is maintained and the discharge amount from the powder feeder 30 is constant, depending on the powder properties of the electrode composition used and the coating conditions, etc. As the allowable range of the remaining amount, for example, a threshold value is specified by the height of the electrode composition stored in the powder feeder 30. As the threshold value, one or both of an upper threshold value and a lower threshold value (both in the example of this embodiment) are defined.

[0049] The control unit 40 has a remaining amount sensor 41 that judges whether the remaining amount of the electrode composition is outside the prescribed allowable value, for example, whether it exceeds the upper threshold or falls below the lower threshold. The remaining amount sensor 41 has, for example, an infrared sensing mechanism, and judges whether the height of the electrode composition in the powder feeder 30 is within the allowable range by detecting infrared rays. The various control functions of the control unit 40 are realized, for example, by a central processing unit (CPU) of a predetermined computer. In this embodiment, the control unit 40 can use the remaining amount sensor 41 to accurately grasp whether the remaining amount of the electrode composition in the powder feeder 30 is within the allowable range prescribed according to the powder properties of the electrode composition used and its application conditions, and when the control unit 40 judges that the remaining amount is outside the allowable range, it is possible to take appropriate measures to keep the discharge amount of the electrode composition constant by appropriately controlling the operation of the alarm unit 50, the adhesion suppression unit 60, the automatic supply unit 70, etc.

[0050] The alarm unit 50 issues an alarm by sounding an alarm, emitting light, or the like when the control unit 40 determines that the remaining amount of the electrode composition is outside the allowable range (upper or lower threshold) based on the measurement by the remaining amount sensor 41. In this embodiment, it is possible to accurately inform an operator, etc., that the storage state of the electrode composition in the powder feeder 30 is not normal.

[0051] The adhesion suppression unit 60 has a hammering mechanism 61 that hammers and removes the electrode composition that has adhered to the inner wall surface of the powder feeder 30, and / or a vibration mechanism 62 that shakes off the electrode composition that has adhered to and accumulated on the inner wall surface of the powder feeder 30. When the control unit 40 determines that the remaining amount of the electrode composition is outside the allowable range (upper threshold or lower threshold), it moves the powder feeder 30 to a predetermined retreat position as necessary. The hammering mechanism 61 is operated in response to an instruction from the control unit 40 to hammer and drop the electrode composition that has solidified and accumulated on the inner wall surface of the powder feeder 30. In addition, the vibration mechanism 62 is operated in response to an instruction from the control unit 40 to vibrate the electrode composition that has solidified and accumulated on the inner wall surface of the powder feeder 30 to shake it off. In the adhesion suppression unit 60, one or both of the hammering mechanism 61 and the vibration mechanism 62 are appropriately operated depending on the degree of adhesion and adhesion of the electrode composition. In this embodiment, when the electrode composition adheres or sticks to the inner wall surface of the powder feeder 30, the adhered deposits of the electrode composition can be appropriately crushed or removed using the hammering mechanism 61 and / or the vibration mechanism 62, thereby restoring uniform fluidity of the electrode composition.

[0052] The automatic supply unit 70 appropriately supplies the electrode composition into the powder feeder 30 based on an instruction from the control unit 40. Specifically, when the control unit 40 determines that the remaining amount of the electrode composition is within an allowable range based on the measurement by the remaining amount sensor 41, for example, the automatic supply unit 70 supplies an amount of the electrode composition specified according to the powder properties of the electrode composition and its application conditions into the powder feeder 30 at a desired constant speed. When the control unit 40 determines that the remaining amount of the electrode composition is outside the allowable range (upper threshold or lower threshold) during operation of the manufacturing apparatus, the automatic supply unit 70 appropriately increases or decreases the supply amount (supply speed) of the electrode composition to the powder feeder 30, temporarily stops the supply of the electrode composition to the powder feeder 30, and, depending on the case, supplies the electrode composition into the powder feeder 30 again at a desired constant speed after the adhesion suppression unit 60 is operated. In this embodiment, the amount of electrode composition discharged from the powder feeder 30 can be kept constant by appropriately adjusting the supply of electrode composition into the powder feeder 30 by the automatic supply unit 70 according to the remaining amount of electrode composition in the powder feeder 30.

[0053] As described above, in this embodiment, the remaining amount of the electrode composition in the powder feeder 30 can be maintained within an allowable range while the fluidity of the electrode composition is kept constant by controlling the remaining amount sensor 41, the adhesion prevention unit 60, the automatic supply unit 70, etc. by the control unit 40. This allows the supply amount (supply speed) of the electrode composition discharged from the powder feeder 30 to be kept constant as desired, making it possible to stably form an electrode composition layer with a uniform thickness.

[0054] The moving roller 80 moves the long sheet-like substrate 100 relative to the powder feeder 30 at a predetermined speed, for example in the direction of the arrow A. The moving roller 80 is driven based on instructions from the control unit 40, and the driving speed and the like are adjusted according to the detection result by the remaining amount sensor 41 and the like.

[0055] The pressurizing unit 90 has, for example, a pair of roll presses 91 and 92. The roll presses 91 and 92 are used to pressurize the electrode composition supplied to a supply region provided on the substrate 100, thereby forming an electrode composition layer that becomes an electrode. Based on instructions from the control unit 40, the pressurizing unit 90 adjusts the pressurizing state (the driving speed of the roll presses 91 and 92 and the linear pressure in the roll presses 91 and 92) for pressing the electrode composition.

[0056] [Electrode manufacturing method] Hereinafter, a method for manufacturing electrodes (positive and negative electrodes) of a lithium ion secondary battery will be described. In this embodiment, a manufacturing method in which a plurality of electrodes are successively formed on a long sheet-like substrate is exemplified. However, the method is not limited to this method, and it is also possible to adopt a so-called batch method in which electrodes are formed one by one on each substrate.

[0057] FIG. 3 is a flow chart showing the process steps of the method for producing an electrode for a lithium ion secondary battery according to this embodiment. The manufacturing method of the electrodes (positive and negative electrodes) according to this embodiment includes a frame member arrangement step S1 for arranging a frame member having a first opening on a substrate, a masking step S2 for arranging a mask layer having a second opening on the frame member, a supply step S3 for supplying an electrode composition into a recess defined by the second opening of the mask layer, a removal step S4 for removing the mask layer, a pressurizing step S5 for pressurizing the electrode composition present inside the frame member, and a cutting step S6 for cutting out an electrode. The manufacturing method according to this embodiment further includes a determination step S11 for determining whether or not the remaining amount (reserved amount) of the electrode composition is within an allowable range, and an adjustment step S12 for adjusting the state of the electrode composition when it is outside the allowable range. When the electrodes are manufactured by the above-mentioned batch method, for example, the cutting step S6 is not necessary.

[0058] (Frame member placement process S1) 4 shows a state in which the frame members are arranged in the frame member arrangement step S1, where (a) is a plan view and (b) is a cross-sectional view taken along the dashed line II' in (a). In the frame member arrangement step S1, a plurality of frame members 101 are arranged continuously on the substrate 100. FIG. 6(a) illustrates three frame members 101 arranged continuously. The frame member 101 has a first opening 101a having the same size as the electrode size, and in the example of FIG. 1, it becomes the frame member 9 of the battery cell 20. When the frame members 101 are arranged on the substrate 100, the first opening 101a of each frame member 101 exposes the portion of the substrate 100 where the electrode composition layer is to be formed. Here, the frame members 101 are arranged continuously means that the adjacent frame members 101 are arranged with their sides in contact with each other. It is also possible to arrange the adjacent frame members 101 at a distance from each other so that their sides face each other.

[0059] In this embodiment, a long sheet-like current collector is used as the substrate 100. In this case, a long film of, for example, a resin current collector is used as the current collectors (positive electrode current collector and negative electrode current collector) of the above-mentioned electrodes. A long film of a separator may be used instead of the current collector. In addition, for example, a transfer film may be used as the substrate 100, and an active material layer formed on the transfer film may be transferred onto the current collector.

[0060] When manufacturing an electrode, by forming an electrode composition layer using a frame member 101 that serves as a sealing material for the battery cell, it is possible to omit the process of removing the frame member after forming the electrode composition layer and then repositioning the sealing material for the battery cell.

[0061] (Masking process S2) The mask layer used in the masking step S2 is shown in Fig. 5, where (a) is a plan view and (b) is a cross-sectional view taken along the dashed line II' in (a). The mask layer 102 has a second opening 102a that is the same shape as the first opening 101a of the frame member 101 in a plan view and is smaller than the first opening 101a by the thickness of the four sides of the mask layer. The second opening 102a has an inner peripheral portion 102b formed in a shape that is bent downward.

[0062] It is preferable to use a material that does not easily generate static electricity on its surface, for example, a metal material such as spring steel, for the mask layer 102. Since static electricity is not easily generated on the surface of the mask layer 102, a part of the supplied electrode composition is not easily attached to the surface of the mask layer 102, and the occurrence of contamination (inclusion of foreign matter) is suppressed.

[0063] 6 shows the state in which the mask layer 102 is disposed in the masking step S2, where (a) is a plan view, (b) is a cross-sectional view taken along dashed line II' in (a), and (c) is a cross-sectional view taken along dashed line II-II' in (a). In the masking step S2, the mask layer 102 is disposed so that its second opening 102a overlaps with the first opening 101a of the frame member 101. The back surface of the mask layer 102 is in close contact with the upper surface of the frame member 101 and the side surface (inner wall surface) of the first opening 101a. The second opening 102a of the mask layer 102 defines a recess 110. In FIG. 6, a region on the surface of the substrate 100 where an electrode composition is to be formed is exposed as the bottom surface of the recess 110.

[0064] Another example of the mask layer used in the masking step S2 is shown in Fig. 7, where (a) is a plan view and (b) is a cross-sectional view taken along the dashed line II' in (a). The mask layer 102 has a second opening 102a that is the same shape as, but smaller in size than, the first opening 101a of the frame member 101 in a plan view. The mask layer 102 has a bent portion 102d, shown by a dashed line, formed in the outer portion of the second opening 102a, for example, so that the inner peripheral portion 102b can be folded downward along the bent portion 102d.

[0065] 7 is used, in the masking step S2, the mask layer 102 is disposed so that its second opening 102a overlaps with the first opening 101a of the frame member 101, and the back surface of the peripheral portion 102c of the mask layer 102 is in close contact with the upper surface of the frame member 101. Then, the inner peripheral portion 102b of the mask layer 102 is folded downward, and the back surface of the inner peripheral portion 102b is in close contact with the side surface (inner wall surface) of the first opening 101a of the frame member 101. The mask layer 102 defines a recess 110.

[0066] (Supply process S3) 8 shows a state in which the electrode composition is supplied to the state in which the mask layer 102 is arranged in the supplying step S3, where (a) is a plan view and (b) is a cross-sectional view taken along the dashed line II' in (a). In the supplying step S3, the above-mentioned powder feeder is used to intermittently supply an electrode composition 120 containing an electrode active material so as to fill the recesses 110 defined by the second openings 102a of the mask layer 102 up to the height of the mask layer 102. The above-mentioned electrode active material (coated positive electrode active material or coated negative electrode active material coated with a conductive assistant and a coating resin) is used as the electrode composition 120. Supplying intermittently means that the electrode composition 120 is supplied only into the recesses 110 of the adjacent frame members 101 at a predetermined interval, so to speak, in a discontinuous manner.

[0067] (Judgment step S11) In the supply step S3, it is determined whether the remaining amount (accumulated amount) of the electrode composition in the powder feeder is within an allowable range (determination step S11). In this embodiment, in the supply step S3, the remaining amount sensor 41 of the control unit 40 monitors the height of the electrode composition in the powder feeder 30. If the height of the electrode composition is within the allowable range, the automatic supply unit 70 continues normal operation, and the supply state of the electrode composition to the powder feeder 30 is kept constant. In this case, after the supply step S3 is completed, the mask removal step S4 is started. In the supply step S3, when the remaining amount sensor 41 of the control unit 40 determines that the height of the electrode composition in the powder feeder 30 is outside the allowable range (upper threshold or lower threshold), the alarm unit 50 is activated to issue an alarm, and the process proceeds to the adjustment step S12.

[0068] (Adjustment process S12) In the adjustment step S12, the automatic supply unit 70 appropriately increases or decreases the supply amount (supply speed) of the electrode composition to the powder feeder 30, or temporarily stops the supply of the electrode composition to the powder feeder 30, in response to an instruction from the control unit 40. When the supply of the electrode composition is stopped, the control unit 40 instructs the powder feeder 30 to move to a predetermined retreat position, and the hammering mechanism 61 and / or the vibration mechanism 62 of the adhesion suppression unit 60 are driven to crush or remove the adhesion deposit of the electrode composition in the powder feeder 30. Thereafter, in response to an instruction from the control unit 40, the powder feeder 30 is returned to the working position, and the automatic supply unit 70 resumes normal operation, and the supply step S3 is performed.

[0069] (Mask removal process S4) In the mask removing step S4, the mask layer 102 is removed from the frame member 101. 9 shows the state after the mask layer 102 has been removed, where (a) is a plan view and (b) is a cross-sectional view taken along the dashed line II' in (a). When the mask layer 102 is removed, the upper surface of the electrode composition 120 present in the first opening 101a of the frame member 101 protrudes from the upper end of the first opening 101a by the thickness of the peripheral portion 102c of the mask layer 102. In addition, the electrode composition 120 present in the first opening 101a of the frame member 101 is spaced apart from the side surface (inner wall surface) of the first opening 101a by the thickness of the inner peripheral edge portion 102b of the mask layer 102.

[0070] (Pressing step S5) FIG. 10 shows how the electrode composition 120 is pressed in the pressing step S5. In the pressurizing step S5, the electrode composition 120 present in the first opening 101a of the frame member 101 is pressed, for example, by the roll press using the pair of roll presses described above, to obtain an electrode composition layer 130. The driving speed of the roll press and the linear pressure in the roll press can be appropriately adjusted according to the composition, fluidity, and density of the electrode composition, etc., of the electrode composition, under the instruction of the control unit 40. It is also possible to use a plate press instead of the roll press.

[0071] 9(b), the pressure application by the roll press in the pressure application step S5 is performed on the electrode composition 120 in a state in which the upper surface protrudes from the upper end of the first opening 101a by the thickness of the peripheral portion 102c of the mask layer 102. By the pressure application step S5, the electrode composition 120 is pressed by the roll press to reduce its thickness and expand its size, thereby forming an electrode composition layer 130 having a flat upper surface and a uniform thickness, the uniform thickness being regulated by the upper surface of the frame member 101 and the size being regulated by the size of the first opening 101a of the frame member 101.

[0072] (Cutting process S6) In the cutting step S6, the substrate 100 having a plurality of electrode composition layers 130 formed on its surface is cut between adjacent frame members 101 to cut out individual electrodes (positive electrodes or negative electrodes) each having an electrode composition layer (positive electrode active material layer or negative electrode active material layer) provided on a current collector (positive electrode current collector or negative electrode current collector) and sealed with a sealant. The method for cutting the substrate is not particularly limited, and examples thereof include known cutting methods (such as cutting with a rotary cutting blade, a guillotine blade, a Thomson type, or a laser).

[0073] In this manner, an electrode (positive electrode or negative electrode) for a lithium ion secondary battery can be manufactured.

[0074] In this embodiment, the frame member 101 is used as a sealant for the battery cells, but the frame member may be removed after the pressing step S5, and a sealant for the battery cells may be placed again. In this case, it is preferable to perform a mask removal step when removing the frame member, and to remove by suction the electrode composition attached to the area where the frame member was placed and its surroundings.

[0075] To manufacture a lithium ion secondary battery using the electrode manufactured according to the present embodiment, for example, a method can be used in which a positive electrode manufactured by the above-mentioned electrode manufacturing method and a negative electrode manufactured by the above-mentioned electrode manufacturing method are stacked with a separator between them so that the coated active material layers (positive electrode active material layer and negative electrode active material layer) face each other to prepare a battery cell, and this battery cell is then covered and sealed with an exterior film.

[0076] As described above, according to this embodiment, when the electrode composition is applied to a specified planned formation area using a powder feeder, an electrode composition layer of uniform thickness can be stably formed even if the supply conditions of the electrode composition change.

[0077] (Apparatus 1) An apparatus for manufacturing an electrode for a lithium ion secondary battery according to one embodiment of the present invention is a powder feeder that supplies an electrode composition including an electrode active material onto a substrate; a control unit that defines an allowable value for a remaining amount of the electrode composition in the powder feeder and controls the remaining amount in relation to the allowable value; has.

[0078] (Device 2) In the device 1, the control unit has a remaining amount sensor that determines whether the remaining amount is outside the allowable value.

[0079] (Device 3) The device 2 has an alarm unit that issues an alarm when the control unit determines that the remaining amount is outside the allowable value.

[0080] (Apparatus 4) In any one of the above-mentioned apparatuses 1 to 3, the permissible value is one or both of an upper threshold value and a lower threshold value of a range permissible for the remaining amount.

[0081] (Apparatus 5) Any one of the above-mentioned apparatuses 1 to 4 has an adhesion suppression part that suppresses adhesion of the electrode composition to the inner wall surface of the powder feeder.

[0082] (Apparatus 6) In the above-mentioned apparatus 5, the adhesion prevention section has at least one of a function of hammering and removing the electrode composition adhering to the inner wall surface of the powder feeder, and a vibration function of shaking off the electrode composition adhering to the inner wall surface of the powder feeder.

[0083] (Apparatus 7) In the above-mentioned apparatus 5 or 6, the operation of the adhesion suppression unit is controlled by the control unit.

[0084] (Apparatus 8) In any one of the above-mentioned apparatuses 1 to 7, the control unit adjusts the conveying speed of a conveying unit that conveys the base material and the pressure state of a pressurizing unit that pressurizes the electrode composition supplied onto the base material.

[0085] (Method 1) A method for producing an electrode for a lithium ion secondary battery according to one embodiment of the present invention includes the following steps: A method for producing an electrode for a lithium ion secondary battery, comprising forming an electrode composition layer made of an electrode composition containing an electrode active material on a substrate, An allowable value for the remaining amount of the electrode composition in the powder feeder is defined, and the electrode composition in the powder feeder is supplied onto the substrate while controlling the remaining amount in relation to the allowable value.

[0086] (Method 2) In the above method 1, a frame member having a first opening is placed on a surface of the base material, and a mask layer having a second opening smaller in size than the first opening is laminated on the frame member; The powder feeder dispenses the electrode composition into a recess defined by the second opening. [Explanation of symbols]

[0087] 1 Secondary battery module 2 negative electrode 3 Positive electrode 7,8 Conductive part 9. Sealing materials 10 Negative electrode current supply layer 11 Negative electrode current collector 12 Negative electrode active material layer 13 Separator 14 Cathode active material layer 15 Positive electrode current collector 16 Positive electrode side current extraction layer 20 Battery Cells 30 Powder Feeder 40 Control section 41 Remaining amount sensor 50 Alarm section 60 Adhesion prevention section 61 Hammering mechanism 62 Vibration mechanism 70 Automatic supply section 80 Transport roller 90 Pressurizing section 91,92 Roll press 100 Base material 101 Frame members 101a First opening 101b Inner edge portion 101c Surrounding area 102 Mask Layer 102a Second opening 110 Recess 120 Electrode composition 130 Electrode composition layer

Claims

1. a powder feeder that supplies an electrode composition including an electrode active material onto a substrate; a control unit that defines an allowable value for a remaining amount of the electrode composition in the powder feeder and controls the remaining amount in relation to the allowable value; having Manufacturing equipment for electrodes for lithium-ion secondary batteries.

2. The control unit has a remaining amount sensor that determines whether the remaining amount is outside the allowable value. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 1.

3. and an alarm unit that issues an alarm when the control unit determines that the remaining amount is outside the allowable value.

3. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 2.

4. The tolerance value is one or both of an upper threshold value and a lower threshold value of a range permitted as the remaining amount, An apparatus for manufacturing an electrode for a lithium ion secondary battery according to any one of claims 1 to 3.

5. An adhesion suppression part that suppresses adhesion of the electrode composition to an inner wall surface of the powder feeder, An apparatus for manufacturing an electrode for a lithium ion secondary battery according to any one of claims 1 to 3.

6. The adhesion suppression unit has at least one of a function of hammering and removing the electrode composition adhered to the inner wall surface of the powder feeder, and a vibration function of shaking off the electrode composition adhered to the inner wall surface of the powder feeder. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 5.

7. The adhesion suppression unit is configured such that the operation of the adhesion suppression unit is controlled by the control unit. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 5.

8. The control unit adjusts a conveying speed of a conveying unit that conveys the base material and a pressurizing state of a pressurizing unit that pressurizes the electrode composition supplied onto the base material. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to any one of claims 1 to 3.

9. A method for producing an electrode for a lithium ion secondary battery, comprising forming an electrode composition layer made of an electrode composition containing an electrode active material on a substrate, a tolerance for a remaining amount of the electrode composition in a powder feeder is defined, and the electrode composition in the powder feeder is supplied onto the substrate while controlling the remaining amount in relation to the tolerance. A method for manufacturing electrodes for lithium-ion secondary batteries.

10. a frame member having a first opening is placed on a surface of the base material, and a mask layer having a second opening smaller in size than the first opening is laminated on the frame member; the powder feeder supplies the electrode composition into a recess defined by the second opening; The method for producing the electrode of the lithium ion secondary battery according to claim 9.

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