CN111201646B - Electrode manufacturing method, electrode and battery - Google Patents
Electrode manufacturing method, electrode and battery Download PDFInfo
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- CN111201646B CN111201646B CN201880065936.9A CN201880065936A CN111201646B CN 111201646 B CN111201646 B CN 111201646B CN 201880065936 A CN201880065936 A CN 201880065936A CN 111201646 B CN111201646 B CN 111201646B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The method for manufacturing an electrode (100) of the present invention is a method for manufacturing an electrode including a collector layer (101) and an electrode active material layer (103), and comprises the steps of: a step (A) for preparing a laminate (150), wherein the laminate (150) is provided with a current collector layer (101) and a planar electrode active material layer (103) which is provided on at least one surface of the current collector layer (101) and has at least one side (103A) that includes a concave-convex structure (103B); and a step (B) for cutting the laminate (150) to a predetermined size to obtain the electrode (100), wherein the laminate (150) further comprises a protective layer (105) formed so as to cover the intersection X of the planned cutting site (150A) of the laminate (150) in the step (B) and the side (103A) on which the uneven structure (103B) is formed.
Description
Technical Field
The invention relates to a method for manufacturing an electrode, an electrode and a battery.
Background
Electrodes used in lithium ion batteries are generally composed mainly of an electrode active material layer and a current collector layer. Such an electrode can be produced by coating an electrode slurry containing an electrode active material on the surface of a current collector layer such as aluminum foil or copper foil, and drying the electrode slurry.
Here, as a method of applying an electrode slurry to the surface of the current collector layer, a batch coating method is known. The intermittent coating method is a method in which coated portions and non-coated portions of electrode paste are alternately formed in the longitudinal direction of a strip-shaped current collector layer. The non-coated portion of the electrode paste is used as a tab for connection to a terminal, for example.
As a related technique of the intermittent coating method of the electrode, for example, a technique described in patent document 1 (japanese patent application laid-open No. 11-260354) is cited.
Patent document 1 describes a method for manufacturing a battery, in which, when manufacturing a battery using an electrode having a current collector and an active material layer intermittently formed on the current collector, the method includes the steps of: a step of forming an active material layer by continuously applying a coating material containing a battery active material, a binder and an organic solvent to the current collector; forming a non-cured region in a portion of the active material layer corresponding to the intermittent portion; and removing the uncured region to form an intermittent portion in the active material layer.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 11-260354
Disclosure of Invention
Problems to be solved by the invention
From the studies by the inventors and the like, it is clear that: the electrode manufactured by the intermittent coating method is prone to burrs during the subsequent cutting process.
The present invention has been made in view of the above circumstances, and provides a method for manufacturing an electrode capable of suppressing the occurrence of burrs.
Means for solving the problems
The present inventors have conducted intensive studies on the cause of burrs generated in the dicing step. The result shows that: the electrode manufactured by the intermittent coating method tends to have a streak of the uneven structure at the coating terminal portion, and tends to have burrs at the cut portions of the uneven structure.
The present inventors have further studied based on the above findings. The result shows that: the present invention has been completed by providing a protective layer on the above-described concave-convex structure at a predetermined portion of the electrode to cut, whereby generation of burrs can be suppressed.
The present invention has been made based on this knowledge.
That is, according to the present invention, there are provided a method for manufacturing an electrode, and a battery shown below.
According to the present invention, there is provided a method for manufacturing an electrode including a current collector layer and an electrode active material layer, the method including:
a step (A) of preparing a laminate including the current collector layer and a planar electrode active material layer provided on at least one surface of the current collector layer and having a concave-convex structure at least one side; and
a step (B) of cutting the laminate into a predetermined size to obtain the electrode,
the laminate further includes a protective layer formed so as to cover an intersection between a predetermined portion of the laminate to be cut and the one side on which the uneven structure is formed in the step (B).
Further, according to the present invention, there is provided an electrode comprising:
a current collector layer;
an electrode active material layer provided on at least one surface of the current collector layer and having a planar shape including a concave-convex structure on at least one side; and
and a protective layer formed so as to cover an end portion of the one side including the concave-convex structure.
Further, according to the present invention, there is provided a battery including the above electrode.
Effects of the invention
According to the present invention, an electrode in which generation of burrs is suppressed can be provided.
Drawings
The above objects and other objects, features and advantages will be further apparent from the following preferred embodiments and the accompanying drawings.
Fig. 1 is a plan view showing an example of the structure of a laminate according to the embodiment of the present invention.
Fig. 2 is a plan view showing an example of the structure of an electrode according to the embodiment of the present invention.
Fig. 3 is a schematic diagram showing an example of the structure of a laminated battery according to the embodiment of the present invention.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the appropriate description thereof is omitted. The drawings are schematic, and the ratio is different from the actual size ratio. The "a to B" in the numerical range means a or more and B or less unless otherwise specified.
< electrode and method for producing electrode >
Hereinafter, the electrode 100 and the method for manufacturing the electrode 100 according to the present embodiment will be described.
Fig. 1 is a plan view showing an example of the structure of a laminate 150 according to the embodiment of the present invention. Fig. 2 is a plan view showing an example of the structure of the electrode 100 according to the embodiment of the present invention.
The method for manufacturing the electrode 100 according to the present embodiment is a method for manufacturing an electrode including the current collector layer 101 and the electrode active material layer 103, and includes at least two steps, namely, the following step (a) and step (B).
(A) A step of preparing a laminate 150, wherein the laminate 150 includes a collector layer 101 and a planar electrode active material layer 103 provided on at least one surface of the collector layer 101 and having at least one side 103A including a concave-convex structure 103B;
(B) A step of cutting the laminate 150 into a predetermined size to obtain an electrode 100;
the laminate 150 further includes a protective layer 105 formed so as to cover the intersection X between the planned cutting portion 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed in the step (B).
As shown in fig. 2, the electrode 100 according to the present embodiment includes: a collector layer 101; a planar electrode active material layer 103 provided on at least one surface of the current collector layer 101 and having at least one side 103A including a concave-convex structure 103B; and a protective layer 105 formed so as to cover an end portion of one side 103A including the concave-convex structure 103B.
The electrode 100 according to the present embodiment is not particularly limited, and is an electrode (positive electrode, negative electrode) for a lithium ion battery such as a lithium ion primary battery or a lithium ion secondary battery, for example.
As described above, it is clear from the study by the present inventors and the like that: the electrode manufactured by the intermittent coating method is prone to burrs during the subsequent cutting process.
The present inventors have conducted intensive studies on the cause of burrs generated in the dicing step. The result shows that: the electrode manufactured by the intermittent coating method tends to have a streak of the uneven structure at the coating terminal portion, and tends to have burrs at the cut portions of the uneven structure.
Here, the cause of the burrs easily generated at the cut portions of the uneven structure is not clear, and the following causes can be considered. First, the drag portion of the concave-convex structure is liable to be loaded by high-pressure pressing due to a small proportion of the electrode active material layer, and electrode active material particles constituting the electrode active material layer are deeply embedded in the current collector layer. It can therefore be considered that: the thickness of the collector layer of the trailing portion becomes thin, and the strength of the collector layer of the trailing portion becomes weak, and therefore, the electrode active material layer of the trailing portion is liable to fall off. The result can be considered as: when cutting, burrs are easily generated by the falling of the convex parts of the concave-convex structure of the tail part. Here, burrs generated in the electrodes may become a cause of battery failure, and thus it is necessary to suppress the generation of burrs.
The present inventors have further studied based on the above findings. The result shows that: the protective layer 105 is provided so as to cover the intersection X between the planned cutting site 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed in the step (B), whereby the occurrence of burrs in the cutting step can be effectively suppressed.
That is, according to the method for manufacturing the electrode 100 of the present embodiment, the protective layer 105 is provided at the intersection X between the planned cutting portion 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed, so that the occurrence of burrs in the step (B) can be effectively suppressed.
As described above, according to the method for manufacturing the electrode 100 of the present embodiment, an electrode in which the occurrence of burrs is suppressed can be provided.
Hereinafter, each step in the structure of the electrode 100 and the manufacturing method of the electrode 100 will be described in detail.
First, each component constituting the electrode active material layer 103 according to the present embodiment will be described.
The electrode active material layer 103 contains an electrode active material, and if necessary, a binder resin, a conductive auxiliary agent, a thickener, and the like.
The electrode active material included in the electrode active material layer 103 according to this embodiment can be appropriately selected according to the application. A positive electrode active material is used for producing a positive electrode, and a negative electrode active material is used for producing a negative electrode.
The positive electrode active material is not particularly limited as long as it is a normal positive electrode active material that can be used in a positive electrode of a lithium ion battery. Examples thereof include lithium and transition metal composite oxides such as lithium-nickel composite oxides, lithium-cobalt composite oxides, lithium-manganese composite oxides, lithium-nickel-cobalt composite oxides, lithium-nickel-aluminum composite oxides, lithium-nickel-cobalt-aluminum composite oxides, lithium-nickel-manganese-cobalt composite oxides, lithium-nickel-manganese-aluminum composite oxides, and lithium-nickel-cobalt-manganese-aluminum composite oxides; tiS (TiS) 2 、FeS、MoS 2 A transition metal sulfide; mnO, V 2 O 5 、V 6 O 13 、TiO 2 And transition metal oxides, olivine-type lithium phosphorus oxides, and the like.
The olivine-type lithium phosphorus oxide contains, for example, at least 1 element selected from Mn, cr, co, cu, ni, V, mo, ti, zn, al, ga, mg, B, nb and Fe, lithium, phosphorus, and oxygen. To improve the properties thereof, these compounds may partially replace a part of the elements with other elements.
Of these, olivine-type lithium iron phosphorus oxide, lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-manganese-cobalt composite oxide, lithium-nickel-manganese-aluminum composite oxide, lithium-nickel-cobalt-manganese-aluminum composite oxide, and lithium-nickel-cobalt-manganese-aluminum composite oxide are preferable. These positive electrode active materials have a large capacity and a large energy density in addition to a high operating potential.
The positive electrode active material may be used alone or in combination of two or more.
The negative electrode active material is not particularly limited as long as it is a normal negative electrode active material that can be used in a negative electrode of a lithium ion battery. Examples thereof include carbon materials such as natural graphite, artificial graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; lithium metal materials such as lithium metal and lithium alloy; metal materials such as silicon and tin; and conductive polymer materials such as polyacene, polyacetylene and polypyrrole. Among these, carbon materials are preferable, and graphite materials such as natural graphite and artificial graphite are particularly preferable.
The negative electrode active material may be used alone in an amount of 1 or in combination of two or more.
The average particle diameter of the electrode active material is preferably 1 μm or more, more preferably 2 μm or more from the viewpoint of suppressing side reactions at the time of charge and discharge and suppressing a decrease in charge and discharge efficiency, and is preferably 100 μm or less, more preferably 50 μm or less from the viewpoints of input/output characteristics and electrode production (smoothness of electrode surface, etc.). The average particle diameter herein means a particle diameter (median diameter: D) at which the cumulative value in the particle size distribution (volume basis) based on the laser diffraction scattering method is 50% 50 )。
The content of the electrode active material is preferably 85 parts by mass or more and 99.8 parts by mass or less, based on 100 parts by mass of the entire electrode active material layer 103.
The binder resin included in the electrode active material layer 103 according to this embodiment can be appropriately selected according to the application. For example, a fluorine-based binder resin that is soluble in a solvent, an aqueous binder that is dispersible in water, or the like can be used.
The fluorine-based binder resin is not particularly limited as long as it can be formed into an electrode and has sufficient electrochemical stability, and examples thereof include polyvinylidene fluoride-based resins and fluororubbers. These fluorine-based binder resins may be used singly or in combination of two or more. Among these, polyvinylidene fluoride resins are preferable. The fluorine-based binder resin may be used by dissolving in a solvent such as N-methyl-pyrrolidone (NMP).
The aqueous binder is not particularly limited as long as it can be formed into an electrode and has sufficient electrochemical stability, and examples thereof include polytetrafluoroethylene-based resins, polyacrylic resins, styrene-butadiene-based rubbers, polyimide-based resins, and the like. These aqueous binders may be used singly or in combination of two or more. Among these, styrene-butadiene rubber is preferable.
In the present embodiment, the aqueous binder refers to a binder that can be dispersed in water to form an aqueous emulsion solution.
When the aqueous binder is used, a thickener may be further used. The thickener is not particularly limited, and examples thereof include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, and ammonium salts and alkali metal salts thereof; a polycarboxylic acid; polyethylene oxide; polyvinylpyrrolidone; polyacrylate such as sodium polyacrylate; polyvinyl alcohol; and water-soluble polymers.
The content of the binder resin is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, based on 100 parts by mass of the entire electrode active material layer 103. When the content of the binder resin is within the above range, the balance of the coatability of the electrode paste, the adhesion of the binder and the battery characteristics is more excellent.
In addition, when the content of the binder resin is equal to or less than the upper limit value, the proportion of the electrode active material increases, and the capacity per unit electrode mass increases, which is preferable. When the content of the binder resin is not less than the above lower limit, electrode peeling is suppressed, which is preferable.
The conductive auxiliary agent included in the electrode active material layer 103 according to the present embodiment is not particularly limited as long as the conductivity of the electrode is improved, and examples thereof include carbon black, ketjen black, acetylene black, natural graphite, artificial graphite, carbon fiber, and the like. These conductive assistants may be used singly or in combination of two or more.
The content of the conductive auxiliary is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, based on 100 parts by mass of the entire electrode active material layer 103. If the content of the conductive auxiliary agent is within the above range, the balance of the coatability of the electrode paste, the adhesiveness of the binder, and the battery characteristics is more excellent.
In addition, when the content of the conductive additive is equal to or less than the upper limit value, the proportion of the electrode active material increases, and the capacity per unit electrode mass increases, which is preferable. If the content of the conductive additive is not less than the above lower limit, the conductivity of the electrode becomes more favorable, and is therefore preferable.
When the total amount of the electrode active material layer 103 is 100 parts by mass, the content of the electrode active material in the electrode active material layer 103 according to the present embodiment is preferably 85 parts by mass or more and 99.8 parts by mass or less. The content of the binder resin is preferably 0.1 parts by mass or more and 10.0 parts by mass or less. Further, the content of the conductive auxiliary agent is preferably 0.1 parts by mass or more and 5.0 parts by mass or less.
When the content of each component constituting the electrode active material layer 103 is within the above range, the balance between the handleability of the electrode 100 and the battery characteristics of the obtained lithium ion battery is particularly excellent.
The density of the electrode active material layer 103 is not particularly limited, and in the case where the electrode active material layer 103 is a positive electrode active material layer, for example, it is preferably 2.0g/cm 3 4.0g/cm above 3 Hereinafter, it is more preferably 2.4g/cm 3 Above and 3.8g/cm 3 The following is more preferably 2.8g/cm 3 Above and 3.6g/cm 3 The following is given. In the case where the electrode active material layer 103 is a negative electrode active material layer, for example, it is preferably 1.2g/cm 3 Above and 2.0g/cm 3 Hereinafter, more preferably 1.3g/cm 3 Above and 1.9g/cm 3 The following is more preferably 1.4g/cm 3 Above and 1.8g/cm 3 The following is given.
When the density of the electrode active material layer 103 is within the above range, the discharge capacity when used at a high discharge rate is preferably improved.
Here, as the density of the electrode active material layer 103 is higher, the electrode active material particles constituting the electrode active material layer 103 are embedded deeper into the collector layer 101, and therefore, the thickness of the collector layer 101 at the trailing portion becomes thinner and the strength of the collector layer 101 becomes weaker, and thus burrs tend to be easily generated in the dicing step. However, according to the method for manufacturing the electrode 100 of the present embodiment, the occurrence of burrs in the dicing step can be effectively suppressed even if the density of the electrode active material layer 103 is high.
Therefore, from the viewpoint of effectively suppressing the generation of burrs of the electrode 100 and further improving the energy density of the resulting lithium ion battery, the density of the positive electrode active material layer is preferably 3.0g/cm 3 The above, more preferably 3.2g/cm 3 The above, particularly preferably 3.3g/cm 3 The density of the negative electrode active material layer is preferably 1.5g/cm 3 The above, more preferably 1.6g/cm 3 The above. Further, from the viewpoint of further suppressing deterioration of cycle characteristics at high temperature, the density of the positive electrode active material layer is preferably 4.0g/cm 3 Hereinafter, it is more preferably 3.8g/cm 3 The following is more preferably 3.6g/cm 3 Hereinafter, the density of the anode active material layer is preferably 2.0g/cm 3 Hereinafter, more preferably 1.9g/cm 3 The following is more preferably 1.8g/cm 3 The following is given.
The thickness of the electrode active material layer 103 is not particularly limited, and may be appropriately set according to desired characteristics. For example, the thickness may be set to be relatively thick from the viewpoint of energy density, and the thickness may be set to be relatively thin from the viewpoint of output characteristics. The thickness (single-sided thickness) of the electrode active material layer 103 may be set appropriately in a range of, for example, 10 μm or more and 250 μm or less, preferably 20 μm or more and 200 μm or less, and more preferably 30 μm or more and 150 μm or less.
The current collector layer 101 according to the present embodiment is not particularly limited, and aluminum, stainless steel, nickel, titanium, an alloy thereof, or the like can be used as the positive electrode current collector layer. Examples of the shape include foil, flat plate, and mesh. Aluminum foil may be particularly suitably used.
Further, as the anode current collector layer 8, copper, stainless steel, nickel, titanium, or an alloy thereof may be used. Examples of the shape include foil, flat plate, and mesh. Copper foil may be particularly suitably used.
The thickness of the positive electrode collector layer is not particularly limited, and is, for example, 1 μm or more and 30 μm or less. The thickness of the negative electrode current collector layer is not particularly limited, and is, for example, 1 μm or more and 20 μm or less.
Here, the thinner the thickness of the collector layer 101 is, the weaker the strength of the collector layer 101 at the trailing portion becomes, and thus burrs tend to be easily generated in the dicing step. However, according to the method for manufacturing the electrode 100 of the present embodiment, the occurrence of burrs in the dicing step can be effectively suppressed even if the thickness of the current collector layer 101 is thin.
Therefore, from the viewpoint of effectively suppressing the generation of burrs of the electrode 100 and reducing the proportion of the current collector layer 101 in the resulting lithium ion battery, and further increasing the energy density of the lithium ion battery, the thickness of the positive electrode current collector layer is preferably less than 25 μm, more preferably less than 20 μm, particularly preferably less than 18 μm, and the thickness of the negative electrode current collector layer 8 is preferably less than 15 μm, more preferably less than 12 μm, particularly preferably less than 10 μm.
(Process (A))
First, a laminate 150 is prepared, and the laminate 150 includes a collector layer 101 and a planar electrode active material layer 103 provided on at least one surface of the collector layer 101 and having at least one side 103A including a concave-convex structure 103B. The laminate 150 further includes a protective layer 105 formed so as to cover the intersection X between the planned cutting portion 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed in the step (B).
Such a laminate 150 can be produced by performing the following steps: for example, a step (A1) of intermittently applying and drying an electrode slurry for forming the electrode active material layer 103 along the longitudinal direction of the strip-shaped current collector layer 101, thereby intermittently forming the electrode active material layer 103 on at least one surface of the current collector layer 101; and a step (A2) of forming the protective layer 105 so as to cover the intersection X of the planned cutting portion 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed.
Here, the concave-convex structure 103B is formed by, for example, tailing of the coating terminal portion in the above-described step (A1).
Hereinafter, a method for manufacturing the laminated body 150 will be described.
First, an electrode paste is prepared.
The electrode slurry may be prepared by mixing an electrode active material, a binder resin, a conductive aid, and a thickener as needed. The mixing ratio of the electrode active material, the binder resin, and the conductive auxiliary agent is the same as the content ratio of the electrode active material, the binder resin, and the conductive auxiliary agent in the electrode active material layer 103, and therefore, the description thereof is omitted here.
The electrode slurry is obtained by dispersing or dissolving an electrode active material, a binder resin, a conductive auxiliary agent, and a thickener as needed in a solvent.
The mixing step of each component is not particularly limited, and for example, an electrode active material and a conductive auxiliary agent are dry-mixed, and then a binder resin and a solvent are added and wet-mixed to prepare an electrode slurry.
In this case, a known mixer such as a ball mill or a planetary mixer may be used as the mixer, and the mixer is not particularly limited.
As the solvent used in the electrode slurry, an organic solvent such as N-methyl-2-pyrrolidone (NMP) or water can be used.
Next, the electrode slurry obtained is intermittently applied to one side in the longitudinal direction of the strip-shaped current collector layer 101, and dried to remove the solvent, whereby the electrode active material layer 103 is intermittently formed on at least one side of the current collector layer 101.
The method of applying the electrode slurry to the current collector layer 101 may generally use a known method. Examples thereof include a reverse roll method, a direct roll method, a doctor blade method, an extrusion method, a curtain method, a gravure method, a bar method, a dipping method, and an extrusion method. Among these, the doctor blade method, and the extrusion method are preferable from the viewpoint of obtaining a good surface state of the coating layer in accordance with physical properties such as tackiness and drying properties of the electrode paste.
The electrode paste may be applied to only one side of the current collector layer 101 or to both sides. When the coating is applied to both sides of the current collector layer 101, the coating may be applied sequentially to each side, or may be applied simultaneously to both sides. Further, the surface of the current collector layer 101 may be coated continuously or intermittently. The thickness, length, and width of the coating layer may be appropriately determined according to the size of the battery.
The method of drying the electrode slurry applied to the current collector layer 101 is not particularly limited, and examples thereof include a method of indirectly heating the electrode slurry from the current collector layer 101 side or the dried electrode active material layer 103 side using a heating roller, and drying the electrode slurry; a method of drying the electrode slurry using electromagnetic waves such as infrared rays, far infrared/near infrared heaters, and the like; and a method in which hot air is blown from the collector layer 101 side or the dried electrode active material layer 103 side to indirectly heat the electrode slurry and dry the electrode slurry.
Next, the electrode active material layer 103 formed on the current collector layer 101 may be pressed together with the current collector layer 101. As the pressing method, roll pressing is preferable from the viewpoint of being able to increase the line pressure and to improve the adhesion between the electrode active material layer 103 and the current collector layer 101. By doing so, the adhesion between the electrode active material layer 103 and the current collector layer 101 is improved, and the density of the electrode active material layer 103 can be increased.
Next, the protective layer 105 is formed so as to cover the intersection X between the planned cutting portion 150A of the laminate 150 and the side 103A on which the uneven structure 103B is formed.
Here, the protective layer 105 may be formed so as to cover the entire concave-convex structure 103B, and is preferably formed only in the vicinity of the intersection X as shown in fig. 1 from the viewpoint of productivity.
The protective layer 105 is not particularly limited as long as it has a strength capable of reinforcing the region of the intersection X and preventing the uneven structure 103B from coming off at the time of dicing the laminate 150, and examples thereof include a thermoplastic resin layer, a resin layer such as an ionizing radiation-curable resin layer and a thermosetting resin layer, and an ink layer formed of ink.
The thermoplastic resin forming the thermoplastic resin layer is not particularly limited, and examples thereof include (meth) acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; polyolefin resins such as polypropylene and polyethylene; a polycarbonate resin; vinyl chloride resin; polyethylene terephthalate (PET); acrylonitrile-butadiene-styrene resin (ABS resin); acrylonitrile-styrene-acrylate resins; and fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene. The thermoplastic resin may be used alone or in combination of two or more.
The ionizing radiation curable resin forming the ionizing radiation curable resin layer is not particularly limited, and examples thereof include unsaturated polyester resins, acrylate resins, methacrylate resins, silicone resins, and the like. The ionizing radiation-curable resin may be used alone or in combination of two or more.
The ionizing radiation curable resin herein refers to a resin that is cured by irradiation with ionizing radiation. The ionizing radiation used for curing the ionizing radiation curable resin layer is not particularly limited, and ionizing radiation having sufficient energy for initiating radical polymerization reaction can be used which acts on the ionizing radiation curable resin, a photo radical polymerization initiator added to the ionizing radiation curable resin layer, a sensitizer and the like to ionize (radical-ionize) them. Electromagnetic waves such as visible rays, ultraviolet rays, X rays, gamma rays, and the like can be used; the electron beam, the charged particle beam such as α beam and β beam, and the like are preferably ultraviolet rays or electron beams from the viewpoints of sensitivity, curing ability, simplicity of the irradiation device (light source/radiation source), and the like.
The thermosetting resin forming the thermosetting resin layer is not particularly limited, and examples thereof include melamine-based resins, phenol-based resins, urea-based resins, epoxy-based resins, amino alkyd-based resins, polyurethane-based resins, polyester-based resins, silicone-based resins, and the like. The thermosetting resin may be used alone or in combination of two or more.
The ink for forming the ink layer is not particularly limited as long as the ink layer having a strength capable of enhancing the region of the intersection X and preventing the uneven structure 103B from falling off at the time of cutting the laminate 150 can be formed, and may be appropriately selected from known inks.
The thickness of the protective layer 105 is not particularly limited as long as it can strengthen the region of the intersection X and prevent the uneven structure 103B from falling off at the time of dicing the laminate 150, and is, for example, preferably 1 μm or more and 50 μm or less, more preferably 3 μm or more and 301 μm or less.
The protective layer 105 can be formed by, for example, applying a resin composition for forming a resin layer, an ink layer, or an ink to the vicinity of the intersection point X, and then drying and/or curing the same.
The method of applying the resin composition or ink is not particularly limited, and for example, a gravure coating method, a die coating method, a lip coating method, a knife coating method, an air knife coating method, a spray coating method, a flow coating method, a roll coating method, a dip coating method, an ink jet method, or the like can be used. These methods may be used alone or in combination. Among these, the inkjet method is preferable in that the protective layer 105 can be continuously formed only in the vicinity of the intersection X.
(Process (B))
Next, the laminate 150 may be cut into a predetermined size to obtain the electrode 100. The method of cutting the electrode 100 from the laminate 150 is not particularly limited, and examples thereof include a method of cutting a plurality of electrodes 100 having a predetermined width in parallel with the longitudinal direction of the laminate 150. The electrode 100 for a battery can also be obtained by punching into a predetermined size according to the use.
Here, the cutting method of the laminate 150 is not particularly limited, and for example, a blade made of metal or the like may be used to cut the laminate 150.
< Battery >
Fig. 3 is a schematic diagram showing an example of the structure of a laminated battery 50 according to the embodiment of the present invention.
The battery according to the present embodiment includes the electrode 100 according to the present embodiment. The battery described in the present embodiment will be described below with reference to a case of the laminated battery 50 in which the battery is a lithium ion battery as a representative example.
The laminated battery 50 includes battery elements in which the positive electrode 1 and the negative electrode 6 are alternately laminated in a plurality of layers with the separator 20 interposed therebetween, and these battery elements are housed together with an electrolyte (not shown) in a container including the flexible film 30. The following composition is presented: the positive electrode terminal 11 and the negative electrode terminal 16 are electrically connected to the battery element, and a part or all of the positive electrode terminal 11 and the negative electrode terminal 16 is led out of the flexible film 30.
The positive electrode 1 has a positive electrode active material coated portion (positive electrode active material layer 2) and an uncoated portion on the front and back of the positive electrode current collector layer 3, respectively, and the negative electrode 6 has a negative electrode active material coated portion (negative electrode active material layer 7) and an uncoated portion on the front and back of the negative electrode current collector layer 8.
The uncoated portion of the positive electrode active material in the positive electrode collector layer 3 is made into a positive electrode tab 10 for connection to the positive electrode terminal 11, and the uncoated portion of the negative electrode active material in the negative electrode collector layer 8 is made into a negative electrode tab 5 for connection to the negative electrode terminal 16.
The positive electrode tabs 10 are collected together at the positive electrode terminal 11 and connected together with the positive electrode terminal 11 by ultrasonic welding or the like, and the negative electrode tabs 5 are collected together at the negative electrode terminal 16 and connected together with the negative electrode terminal 16 by ultrasonic welding or the like. One end of the positive electrode terminal 11 is led out of the flexible film 30, and one end of the negative electrode terminal 16 is also led out of the flexible film 30.
An insulating member may be formed as needed at the boundary portion 4 between the coated portion (positive electrode active material layer 2) and the uncoated portion of the positive electrode active material, and the insulating member may be formed not only at the boundary portion 4 but also in the vicinity of the boundary portion between the positive electrode tab 10 and the positive electrode active material.
An insulating member may be formed in the same manner as the boundary 9 between the coated portion (negative electrode active material layer 7) and the uncoated portion of the negative electrode active material, if necessary, and may be formed in the vicinity of the boundary between the negative electrode tab 5 and the negative electrode active material.
In general, the external dimension of the anode active material layer 7 is larger than the external dimension of the cathode active material layer 2 and smaller than the external dimension of the separator 20.
(lithium salt-containing nonaqueous electrolyte)
The nonaqueous electrolyte solution containing a lithium salt used in the present embodiment may be appropriately selected from known materials depending on the type of electrode active material, the use of the lithium ion battery, and the like.
Specific examples of the lithium salt include LiClO 4 、LiBF 6 、LiPF 6 、LiCF 3 SO 3 、LiCF 3 CO 2 、LiAsF 6 、LiSbF 6 、LiB 10 Cl 10 、LiAlCl 4 、LiCl、LiBr、LiB(C 2 H 5 ) 4 、CF 3 SO 3 Li、CH 3 SO 3 Li、LiC 4 F 9 SO 3 、Li(CF 3 SO 2 ) 2 N, lithium lower fatty acid carboxylate, and the like.
The solvent for dissolving the lithium salt is not particularly limited as long as it is a solvent generally used as a liquid for dissolving the electrolyte, and examples thereof include carbonates such as Ethylene Carbonate (EC), propylene Carbonate (PC), butylene Carbonate (BC), dimethyl carbonate (DMC), ethylene Methyl Carbonate (EMC), diethyl carbonate (DEC), ethylmethyl carbonate (MEC), and Vinylene Carbonate (VC); lactones such as gamma-butyrolactone and gamma-valerolactone; ethers such as trimethoxy methane, 1, 2-dimethoxyethane, diethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide; oxapentanes such as 1, 3-dioxolane and 4-methyl-1, 3-dioxolane; nitrogen-containing solvents such as acetonitrile, nitromethane, formamide, dimethylformamide, and the like; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and ethyl propionate; triesters of phosphoric acid, diethylene glycol dimethyl ether; triethylene glycol dimethyl ether; sulfolanes such as sulfolane and methyl sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sultones such as 1, 3-propane sultone, 1, 4-butane sultone, and naphthalene sultone. One kind of them may be used alone, or two or more kinds may be used in combination.
(Container)
In the present embodiment, a known member can be used for the container, and the flexible film 30 is preferably used from the viewpoint of weight reduction of the battery. The flexible film 30 may be a film having a resin layer provided on the front and rear surfaces of a metal layer serving as a base material. The metal layer may be selected from those having a barrier property against leakage of electrolyte and invasion of moisture from the outside, and aluminum, stainless steel, or the like may be used. The exterior body is formed by providing a heat-fusible resin layer such as a modified polyolefin on at least one surface of the metal layer, disposing the heat-fusible resin layers of the flexible film 30 so as to face each other with the battery element interposed therebetween, and heat-welding the periphery of the portion accommodating the battery element. A resin layer such as a nylon film or a polyester film may be provided on the surface of the exterior body which is the surface opposite to the surface on which the heat-fusible resin layer is formed.
(terminal)
In the present embodiment, a terminal made of aluminum or an aluminum alloy may be used as the positive electrode terminal 11, and copper or a copper alloy, a terminal obtained by plating nickel on these, or the like may be used as the negative electrode terminal 16. The terminals are led out of the container, and a heat-fusible resin may be provided in advance at a portion of each terminal located at a portion where the periphery of the exterior body is heat-fused.
(insulating part)
When the insulating member is formed by the boundary portions 4 and 9 between the coated portion and the uncoated portion of the active material, polyimide, glass fiber, polyester, polypropylene, or a material containing these components may be used. These members can be welded to the boundary portions 4 and 9 by applying heat thereto, or the boundary portions 4 and 9 can be coated with a gel-like resin and dried, whereby an insulating member can be formed.
(spacer)
The spacer 20 according to the present embodiment preferably includes a resin layer containing a heat-resistant resin as a main component.
Here, the resin layer is formed of a heat-resistant resin as a main component. Here, "main component" means that the proportion in the resin layer is 50 mass% or more, and means that: the content is preferably 70% by mass or more, more preferably 90% by mass or more, and may be 100% by mass.
The resin layer constituting the spacer 20 according to the present embodiment may be a single layer or two or more layers.
Examples of the heat-resistant resin forming the resin layer include one or more selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, polycarbonate, polyester carbonate, aliphatic polyamide, wholly aromatic polyester, polyphenylene sulfide, poly-p-phenylene benzobisoxazole, polyimide, polyarylate, polyetherimide, polyamideimide, polyacetal, polyether ether ketone, polysulfone, polyether sulfone, fluorine-based resin, polyether nitrile, modified polyphenylene ether, and the like.
Among these, from the viewpoint of excellent balance of heat resistance, mechanical strength, stretchability, price, and the like, one or two or more selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, aliphatic polyamide, wholly aromatic polyamide, semiaromatic polyamide, and wholly aromatic polyester are preferable, one or two or more selected from polyethylene terephthalate, polybutylene terephthalate, aliphatic polyamide, wholly aromatic polyamide, and semiaromatic polyamide are more preferable, and one or two or more selected from polyethylene terephthalate and wholly aromatic polyamide are more preferable.
The resin layer constituting the spacer 20 according to the present embodiment is preferably a porous resin layer. In this way, when an abnormal current or a rise in the battery temperature occurs in the lithium ion battery, the micropores of the porous resin layer are blocked, and the flow of current can be blocked, so that thermal runaway of the battery can be avoided.
The porosity of the porous resin layer is preferably 20% or more and 80% or less, more preferably 30% or more and 70% or less, and particularly preferably 40% or more and 60% or less, from the viewpoint of balance between mechanical strength and lithium ion conductivity.
The porosity can be determined by the following formula.
ε＝{1-Ws/(ds·t)}×100
Here, ε: porosity (%), ws: weight per unit area (g/m) 2 ) And ds: true density (g/cm) 3 ) And t: film thickness (μm).
The planar shape of the separator 20 according to the present embodiment is not particularly limited, and may be appropriately selected according to the shape of the electrode or the current collector, and may be rectangular, for example.
From the viewpoint of balance between mechanical strength and lithium ion conductivity, the thickness of the spacer 20 according to the present embodiment is preferably 5 μm or more and 50 μm or less.
While the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above may be adopted.
The present invention is not limited to the above-described embodiments, and includes modifications, improvements, and the like within a range that can achieve the object of the present invention.
This application claims priority based on japanese application publication No. 2017-202717, filed on 10/19 in 2017, and the entire disclosure of which is incorporated herein by reference.
Claims (12)
1. A method for manufacturing an electrode including a collector layer and an electrode active material layer, comprising:
a step (A) of preparing a laminate including the current collector layer and a planar electrode active material layer provided on at least one surface of the current collector layer and having a concave-convex structure at least one side; and
a step (B) of cutting the laminate into a predetermined size to obtain the electrode,
the laminate further includes a protective layer formed so as to cover an intersection between a predetermined portion of the laminate to be cut and the side on which the uneven structure is formed in the step (B).
2. The method for manufacturing an electrode according to claim 1, wherein,
the step (A) includes: and a step (A1) of intermittently forming the electrode active material layer on at least one surface of the current collector layer by intermittently applying and drying an electrode slurry for forming the electrode active material layer along the longitudinal direction of the strip-shaped current collector layer.
3. The method for manufacturing an electrode according to claim 2, wherein the uneven structure is a structure formed by tailing of a coating terminal portion in the step (A1).
4. The method for producing an electrode according to any one of claim 1 to 3, wherein,
when the collector layer is a positive electrode collector layer, the thickness of the collector layer is less than 25 μm,
when the current collector layer is a negative electrode current collector layer, the thickness of the current collector layer is less than 15 μm.
5. The method for producing an electrode according to any one of claim 1 to 3, wherein,
when the electrode active material layer is a positive electrode active material layer, the density of the electrode active material layer is 3.0g/cm 3 The above-mentioned steps are carried out,
when the electrode active material layer is a negative electrode active material layer, the density of the electrode active material layer is 1.5g/cm 3 The above.
6. The method for producing an electrode according to any one of claims 1 to 3, wherein the electrode is an electrode for a lithium ion battery.
7. An electrode, comprising:
a current collector layer;
an electrode active material layer provided on at least one surface of the current collector layer and having a planar shape including a concave-convex structure on at least one side; and
and a protective layer formed so as to cover an end portion of the one side including the concave-convex structure.
8. The electrode according to claim 7, wherein,
when the collector layer is a positive electrode collector layer, the thickness of the collector layer is less than 25 μm,
when the current collector layer is a negative electrode current collector layer, the thickness of the current collector layer is less than 15 μm.
9. The electrode according to claim 7 or 8, wherein,
when the electrode active material layer is a positive electrode active material layer, the density of the electrode active material layer is 3.0g/cm 3 The above-mentioned steps are carried out,
when the electrode active material layer is a negative electrode active material layer, the density of the electrode active material layer is 1.5g/cm 3 The above.
10. The electrode according to claim 7 or 8, which is an electrode for a lithium ion battery.
11. A battery provided with an electrode, comprising the electrode according to any one of claims 7 to 10.
12. The battery with electrodes according to claim 11, wherein the battery is a lithium ion battery.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-202717 | 2017-10-19 | ||
| JP2017202717 | 2017-10-19 | ||
| PCT/JP2018/034760 WO2019077931A1 (en) | 2017-10-19 | 2018-09-20 | Method for manufacturing electrode, electrode, and cell |
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| Publication Number | Publication Date |
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| CN111201646A CN111201646A (en) | 2020-05-26 |
| CN111201646B true CN111201646B (en) | 2023-07-18 |
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| CN201880065936.9A Active CN111201646B (en) | 2017-10-19 | 2018-09-20 | Electrode manufacturing method, electrode and battery |
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| JP (1) | JPWO2019077931A1 (en) |
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| WO (1) | WO2019077931A1 (en) |
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| WO2021145061A1 (en) * | 2020-01-17 | 2021-07-22 | パナソニックＩｐマネジメント株式会社 | Coating method and coating device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006172827A (en) * | 2004-12-14 | 2006-06-29 | Dainippon Printing Co Ltd | Clearance determination method of gang edge cutting device, cutting method by gang edge cutting device, and gang edge cutting device |
| CN102658255A (en) * | 2012-05-10 | 2012-09-12 | 深圳市浩能科技有限公司 | Intermittent extrusion coater and coating method |
| CN105244470A (en) * | 2015-09-11 | 2016-01-13 | 合肥国轩高科动力能源有限公司 | Positive plate of high-safety lithium-ion laminated battery and preparation method of positive plate |
| JP2016081742A (en) * | 2014-10-17 | 2016-05-16 | 株式会社豊田自動織機 | Manufacturing method of electrode |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6919103B2 (en) * | 2016-03-18 | 2021-08-18 | 株式会社エンビジョンＡｅｓｃジャパン | Positive electrode mixture for secondary batteries, positive electrode manufacturing method for secondary batteries, and secondary battery manufacturing method |
| JP6344507B2 (en) * | 2017-06-06 | 2018-06-20 | 日本電気株式会社 | Anode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using the same |
-
2018
- 2018-09-20 JP JP2019549163A patent/JPWO2019077931A1/en active Pending
- 2018-09-20 WO PCT/JP2018/034760 patent/WO2019077931A1/en active Application Filing
- 2018-09-20 CN CN201880065936.9A patent/CN111201646B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006172827A (en) * | 2004-12-14 | 2006-06-29 | Dainippon Printing Co Ltd | Clearance determination method of gang edge cutting device, cutting method by gang edge cutting device, and gang edge cutting device |
| CN102658255A (en) * | 2012-05-10 | 2012-09-12 | 深圳市浩能科技有限公司 | Intermittent extrusion coater and coating method |
| JP2016081742A (en) * | 2014-10-17 | 2016-05-16 | 株式会社豊田自動織機 | Manufacturing method of electrode |
| CN105244470A (en) * | 2015-09-11 | 2016-01-13 | 合肥国轩高科动力能源有限公司 | Positive plate of high-safety lithium-ion laminated battery and preparation method of positive plate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111201646A (en) | 2020-05-26 |
| JPWO2019077931A1 (en) | 2020-11-05 |
| WO2019077931A1 (en) | 2019-04-25 |
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