Device for manufacturing lithium ion secondary battery electrode

Abstract

To quickly and surely remove adhesives and significantly reduce adversary effects on subsequent processes due to the adhesives, if a part of an electrode composition adheres to areas other than an electrode composition layer during electrode manufacturing.SOLUTION: A device for manufacturing a lithium ion secondary battery electrode includes a removal mechanism 40 to remove an unnecessary electrode composition. The removal mechanism 40 includes: a first mechanism to scrape off an electrode composition that is scattered to portions other than a supply portion of the electrode composition on the base material 100; a second mechanism to remove the scraped electrode composition; and a third mechanism to wipe off and move the electrode composition. The first mechanism and the second mechanism are integrated.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus 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 current collector, a positive electrode active material layer, a separator, a negative electrode current 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 current collector and the positive electrode active material layer, and a negative electrode is configured by the negative electrode current collector and the negative electrode active material layer, and these are used as electrodes.

[0003] For producing an electrode for a lithium ion secondary battery, a method is known in which a mask having an opening in a region where an electrode composition layer is to be formed is placed on a sheet-like substrate, an electrode composition is applied onto the mask including inside the opening, and the mask and any unnecessary electrode composition thereon are removed to leave the electrode composition only in the region where the electrode composition is to be formed on the substrate, thereby forming an electrode composition layer, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-027043 Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing an electrode for a lithium ion secondary battery, when removing the electrode composition on the mask together with the mask, a part of the electrode composition may fall off and fall and adhere to the periphery of the electrode composition layer. Furthermore, a part of the fallen material of the electrode composition layer may scatter due to the impact of the fall and adhere to a conveying jig, etc. If such a deposit remains, there is a problem that the coating range of the electrode composition is not well defined and contamination occurs in the subsequent steps.

[0006] The present invention aims to provide an apparatus for manufacturing electrodes for lithium ion secondary batteries, which is capable of quickly and reliably removing any adhesion of an electrode composition that adheres to the periphery of an electrode composition layer, etc., during electrode production. [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 containing an electrode active material to a predetermined site on the substrate; a first mechanism for scraping off the electrode composition that has scattered on a portion other than the predetermined portion on the substrate; a second mechanism for removing the scraped electrode composition; Equipped with Manufacturing equipment for electrodes for lithium-ion secondary batteries. Effect of the Invention

[0008] According to the lithium ion secondary battery electrode manufacturing apparatus of the present invention, when part of the electrode composition adheres to the periphery of the electrode composition layer during electrode manufacturing, the adhesion can be quickly and reliably removed, making it possible to significantly reduce the adverse effects caused by the remaining adhesion. [Brief description of the drawings]

[0009] [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. 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 3A] FIG. 2 is a perspective view showing a suction nozzle of the first example. [Figure 3B] FIG. 2 is a perspective view showing a suction nozzle of the first example. [Figure 3C] FIG. 2 is a perspective view showing a suction nozzle of the first example. [Figure 4A] FIG. 11 is a perspective view showing a suction nozzle of a second example. [Figure 4B] FIG. 11 is a perspective view showing a suction nozzle of a second example. [Figure 4C] FIG. 11 is a side view showing a suction nozzle of a second example. [Figure 4D] FIG. 11 is a front view showing a suction nozzle of a second example. [Diagram 5] 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 6] 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. [Figure 7] 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 8] 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 9] 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 10] 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 11] FIG. 11 is a side view showing an example of removing an electrode composition using the suction nozzle and protrusion portion described in the second example. [Figure 12] 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 13]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

[0010] 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.

[0011] (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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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. Alternatively, 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.

[0018] Preferred embodiments of each of the constituent materials that make up the battery cell 20 will be described below.

[0019] 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 Al1 / 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 a+b+c=1 is satisfied. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The thickness of the positive electrode active material layer is not particularly limited, but from the viewpoint of battery performance, it is preferably 2500 μm to 600 μm, and more preferably 350 μm to 500 μm.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 current collector is not particularly limited, and may be a sheet-like current 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 , LiBF4 , 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 5 SO 2 ) 2 etc.] and LiPF 6 It is.

[0042] 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.

[0043] 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.

[0044] [Electrode manufacturing equipment] An apparatus for manufacturing electrodes for lithium ion secondary batteries will be described below. FIG. 2 is a cross-sectional view that illustrates a schematic configuration of an apparatus for manufacturing an electrode for a lithium ion secondary battery according to this embodiment.

[0045] The electrode manufacturing apparatus of this embodiment includes a powder feeder 30 for the electrode composition, a mechanism 40 for removing unnecessary electrode composition, a transfer roller 50 for moving the substrate 100, and a pressurizing mechanism 60 for the electrode composition supplied onto the substrate 100.

[0046] 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.

[0047] The removal mechanism 40 includes a first mechanism for scraping off the electrode composition scattered in areas other than the electrode composition supply area (such as the periphery of the electrode composition layer), a second mechanism for removing the scraped off electrode composition, and a third mechanism for brushing off and moving unnecessary electrode composition. In this embodiment, for example, the first mechanism and the second mechanism are integrated. Specifically, the second mechanism has a suction nozzle for sucking up the electrode composition, and the first mechanism is a soft protrusion provided on a part of the periphery at the tip of the suction nozzle. The first mechanism and the second mechanism may be provided separately.

[0048] (First example of suction nozzle) 3A and 3B are perspective views showing the suction nozzle of the first example from different angles, and FIG. 3C is a cross-sectional view of the suction nozzle of the first example, with a part cut away. The suction nozzle 21, which is the second mechanism for removing the unnecessary electrode composition, is, for example, cylindrical in shape with a hollow suction passage formed therein, and the rear part is a first region 21A with the same thickness and uniform inner diameter (diameter of the suction passage) d1, and the front part is a second region 21B in which the inner diameter gradually increases toward the tip and becomes thinner toward the tip, and the tip has an inner diameter d2 (>d1). This configuration allows the unnecessary electrode composition to be sucked efficiently and quickly. In the suction nozzle 21, at the tip of the second region 21B, the approximately semicircular part along the circumference is the protrusion 22, which is the first mechanism for scraping off the unnecessary electrode composition. Here, the protrusion 22 is made of a flexible material such as resin, and functions as a scraper for scraping off the attached electrode composition. In the suction nozzle 21, only the protrusion 22 may be made of the resin, etc., and the other parts may be made of a material harder than the protrusion 22, or the other parts may be made of the same flexible resin, etc. as the protrusion 22. The suction nozzle 21 is appropriately connected to a suction driving device (not shown) at the rear end of the first region 21A.

[0049] As described later, when a mask layer is provided on a frame member arranged on a substrate, and an electrode composition is supplied and embedded in a supply region defined by a recess formed therein, the electrode composition may scatter and adhere to the mask layer. The mask layer is removed after the electrode composition is supplied, and when the mask layer is removed, a part of the unnecessary electrode composition may remain on the frame member and adhere thereto, or may fall onto the substrate. In such a case, in the first example of the present embodiment, the unnecessary electrode composition is scraped off by the protrusion 22, and at the same time, is removed by suction with the suction nozzle 21. In the present embodiment, by using the suction nozzle 21 and the protrusion 22 integrated therewith, even if the electrode composition adheres to a structurally complicated portion, for example, a part of the protrusion 22, which is made of a soft material, appropriately deforms and comes into contact, and the electrode composition attached to the corner or the like can be reliably peeled off, and the electrode composition can be quickly removed by suction with the suction nozzle 21.

[0050] (Second example of suction nozzle) FIG. 4A is a perspective view showing a suction nozzle of the second example, FIG. 4B is a cross-sectional view of the suction nozzle of the second example with a portion cut away, FIG. 4C is a side view of the suction nozzle of the second example, and FIG. 4D is a front view of the suction nozzle of the second example. The suction nozzle 31, which is the second mechanism for removing unnecessary electrode composition, has a cylindrical first region 31A at the rear and a substantially rectangular parallelepiped second region 31B at the front. A hollow suction passage 31a with a circular cross section is formed in the first region 31A, and a hollow suction passage 31b with a flared shape is formed in the second region 31B, and the suction passages 31a and 31b are connected to each other. In the second region 31B, the tip is substantially rectangular as shown in FIG. 4C when viewed from the front, and a protrusion 32 is formed from the upper edge of the tip to a part of the side, and a protrusion 33, which is the first mechanism for scraping off unnecessary electrode composition, is formed along the lower edge of the tip.

[0051] The protrusion 32 is provided at a position narrowing the upper corner portion at the entrance of the suction passage 31b. The protrusion 33 is made of a flexible material such as resin, is thinner than the protrusion 32, and is tapered such that the thickness gradually decreases toward the front, for example, and functions as a scraper for scraping off the attached electrode composition and a brush for collecting fine electrode composition. The protrusion 33 is provided at a position narrowing the lower corner portion at the entrance of the suction passage 31b. In the suction nozzle 31, only the protrusion 33 may be made of the resin or the like, and the other parts may be made of a material harder than the protrusion 33, or the other parts may be made of the same flexible resin or the like as the protrusion 33. The suction nozzle 31 is appropriately connected to a suction drive device (not shown) at the rear end of the first region 31A.

[0052] In a second example of this embodiment, unnecessary electrode composition is scraped off by protrusion 33, and the remaining fine electrode composition is scraped off or collected by protrusion 33, and simultaneously suctioned and removed by suction nozzle 31. In this embodiment, by using suction nozzle 31 and protrusion 33 integrated therewith, even if the electrode composition adheres to a structurally complicated portion, for example, a part of protrusion 33 which is thin and made of a soft material can appropriately deform and enter into contact, and the electrode composition adhered to the corner or the like can be reliably peeled off and collected, and the electrode composition can be quickly suctioned and removed by suction nozzle 31.

[0053] 4D, at the tip of the second region 31B of the suction nozzle 31, the upper corner at the entrance of the suction passage 31b is narrowed by a protrusion 32, and the lower corner is narrowed by a protrusion 33, so that the vertical width at the entrance of the suction passage 31b is narrower than the diameter of the suction passage 31a. This structure allows the suction nozzle 31 to obtain a higher suction force.

[0054] The third mechanism, the cleaning unit (not shown), has a brush-like member made of a soft material. In this embodiment, for example, when the electrode composition remains in a structurally complicated area, the remaining electrode composition is first swept out and moved using the cleaning unit, and then the electrode composition is sucked and removed using the suction nozzle 21 or 31. In this manner, in this embodiment, the remaining unnecessary electrode composition can be moved from a place where it is difficult to remove, and can be easily and reliably removed.

[0055] The transfer roller 50 transfers 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.

[0056] The pressure mechanism 60 has, for example, a pair of roll presses 51 and 52. The roll presses 51 and 52 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.

[0057] [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.

[0058] FIG. 5 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 supplying step S3 for supplying an electrode composition into a recess defined by the second opening of the mask layer, a removing 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 the electrodes. Furthermore, the manufacturing method according to this embodiment appropriately includes suction and removal steps S11 and S12 for removing unnecessary electrode composition. When the electrodes are manufactured by the above-mentioned batch method, for example, the cutting step S6 is not necessary.

[0059] (Frame member placement process S1) 6 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.

[0060] 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.

[0061] 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.

[0062] (Masking process S2) 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 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.

[0063] 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.

[0064] 8 shows a state in which the mask layer 102 is disposed in the masking step S2. (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. 8, 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.

[0065] Another example of the mask layer used in the masking step S2 is shown in Fig. 9, 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.

[0066] 9 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.

[0067] (Supply process S3) 10 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.

[0068] (Suction removal process S11) When the supplying step S3 is completed, unnecessary electrode composition may be attached to the mask layer 102. In this case, in this embodiment, the electrode composition attached to the mask layer 102 is removed by using the above-mentioned first mechanism and second mechanism of the electrode manufacturing apparatus.

[0069] Specifically, the suction nozzle 21 and the protrusions 22 integrated therewith described in the first example are used, and the electrode composition adhering to the mask layer 102 is scraped off by the protrusions 22, and at the same time, the electrode composition is sucked and removed by the suction nozzle 21. Alternatively, the suction nozzle 31 and the protrusions 33 integrated therewith described in the second example are used, and the electrode composition adhering to the mask layer 102 is scraped off by the protrusions 33 to be collected, and at the same time, the electrode composition is sucked and removed by the suction nozzle 31.

[0070] FIG. 11 shows an example of removing the electrode composition using the suction nozzle 31 and the protrusion 33 described in the second example. 11, when the supplying step S3 is performed, a part of the electrode composition is scattered and adheres onto the mask layer 102, and this electrode composition is illustrated as unnecessary electrode composition 120a. In this case, the suction nozzle 31 is disposed so that the tip of the protrusion 33 abuts against the surface of the mask layer 102 while being inclined at, for example, about 45° from the surface of the mask layer 102, and the unnecessary electrode composition 120a is scraped off and collected by the protrusion 33. At the same time as the electrode composition 120a is peeled off and collected, the electrode composition 120a peeled off from the surface of the mask layer 102 is suctioned and removed by the suction nozzle 31.

[0071] It is also possible to use the cleaning unit, which is the third mechanism described above, to move unnecessary electrode composition on mask layer 102 to another location, and then suction and remove the electrode composition using suction nozzle 21 or 31 .

[0072] (Mask removal process S4) In the mask removing step S4, the mask layer 102 is removed from the frame member 101. 12 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.

[0073] (Suction removal process S12) When the mask removal step S4 is completed, unnecessary electrode composition that has scattered when the mask layer 102 is peeled off may fall onto and adhere to the frame member 101 and its surroundings. In this case, in this embodiment, the electrode composition adhered to the frame member 101 and the like is removed using the above-mentioned first mechanism and second mechanism of the electrode manufacturing apparatus.

[0074] Specifically, the suction nozzle 21 and the protrusion 22 integrated therewith described in the first example are used, and the electrode composition adhering to the frame member 101 is scraped off by the protrusion 22, and at the same time, the electrode composition is sucked and removed by the suction nozzle 21. Alternatively, the suction nozzle 31 and the protrusion 33 integrated therewith described in the second example are used, and the electrode composition adhering to the frame member 101 is scraped off by the protrusion 33 to be collected, and at the same time, the electrode composition is sucked and removed by the suction nozzle 31.

[0075] The electrode composition on frame member 101 may be moved to another location using the cleaning unit, which is the third mechanism described above, and the electrode composition may be removed by suction using suction nozzle 21 or 31.

[0076] (Pressing step S5) FIG. 13 shows how the electrode composition 120 is pressed in the pressing step S5. In the pressing step S5, the electrode composition 120 present in the first opening 101a of the frame member 101 is pressed, for example, by a roll press using the pair of roll presses described above, to obtain an electrode composition layer 130. The line pressure in the roll press is not particularly limited, and can be adjusted according to the composition, fluidity, and density of the electrode composition. It is also possible to use a plate press instead of the roll press.

[0077] 12(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.

[0078] (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).

[0079] In this manner, an electrode (positive electrode or negative electrode) for a lithium ion secondary battery can be manufactured.

[0080] 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.

[0081] 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.

[0082] As described above, according to this embodiment, when part of the electrode composition adheres to the periphery of the electrode composition layer during electrode production, the adhesion can be quickly and reliably removed, and the adverse effects caused by the remaining adhesion can be significantly reduced.

[0083] (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 containing an electrode active material to a predetermined site on the substrate; a first mechanism for scraping off the electrode composition that has scattered on a portion other than the predetermined portion on the substrate; a second mechanism for removing the scraped electrode composition; Equipped with.

[0084] (Apparatus 2) In the above-mentioned apparatus 1, the second mechanism has a suction nozzle that sucks up the electrode composition.

[0085] (Apparatus 3) In the above-mentioned apparatus 2, the first mechanism is a flexible protrusion provided on part of the periphery at the tip of the suction nozzle.

[0086] (Device 4) In the above-mentioned device 3, the protrusion has a shape in which the thickness gradually decreases toward the front.

[0087] (Apparatus 5) Any one of the above-mentioned apparatuses 1 to 4 has a third mechanism for brushing and moving the electrode composition. [Explanation of symbols]

[0088] 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 21,31 Suction nozzle 21A,31A 1st area 21B,31B 2nd area 22,32,33 Protrusion 30 Powder Feeder 40 Removal mechanism 50 Transport roller 60 Pressure Mechanism 51,52 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 containing an electrode active material to a predetermined site on the substrate; a first mechanism for scraping off the electrode composition that has scattered on a portion other than the predetermined portion on the substrate; a second mechanism for removing the scraped electrode composition; Equipped with Manufacturing equipment for electrodes for lithium-ion secondary batteries.

2. The second mechanism has a suction nozzle that suctions the electrode composition. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 1.

3. the first mechanism is a flexible protrusion provided on a part of a periphery at a tip of the suction nozzle; 3. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 2.

4. The protrusion has a shape in which the thickness gradually decreases toward the front. An apparatus for manufacturing an electrode for a lithium ion secondary battery according to claim 3.

5. a third mechanism for brushing and moving the electrode composition; An apparatus for manufacturing an electrode for a lithium ion secondary battery according to any one of claims 1 to 4.

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