JP6533053B2 - Method of manufacturing electrode for lithium ion battery - Google Patents

Description

  The present invention relates to a method for producing an electrode for a lithium ion battery, in which a powder containing an electrode active material or the like is compression-molded to produce an electrode for a lithium ion battery.

  The lithium ion battery, which is compact, light in weight, high in energy density, and capable of repeated charge and discharge, is expected to expand in the future in view of environmental protection. Lithium ion batteries are used in fields such as mobile phones and laptop computers because of their high energy density, but with the expansion and development of applications, performance is further improved, such as resistance reduction and capacity increase. Is required.

  The lithium ion battery electrode can be obtained as an electrode sheet. For example, in Patent Document 1, a binder is applied to a substrate and then powder is dispersed to form an active material layer on the surface of the substrate, and the substrate is allowed to pass between a pair of pressing rolls to be a substrate The manufacturing method of the lithium ion secondary battery which obtains an electrode sheet by compression-molding an active material layer continuously on the surface of is disclosed.

JP, 2014-078497, A

  By the way, when manufacturing an electrode sheet using the manufacturing method of the above-mentioned lithium ion secondary battery, when a base material is made to pass between a pair of rolls for presses, powder flows outside the cross direction and an active material layer The sagging occurs at the end of the For this reason, both ends in the width direction of the active material layer are insufficiently pressed, and the adhesion between the active material layer and the base is reduced, and as a result, the active material layer and the base at both ends in the width direction of the active material layer There is a problem that the peeling strength with the

  An object of the present invention is to provide a method of manufacturing an electrode for a lithium ion battery capable of maintaining high peel strength between the active material layer and the base at both widthwise end portions of the active material layer.

  As a result of intensive investigations, the present inventors apply the first binder coating solution to the surface of the base material corresponding to the central part in the width direction of the lithium ion battery electrode active material layer, and It is found that the above object can be achieved by applying a second binder coating solution different from the first binder coating solution on the substrate surface corresponding to both ends in the width direction of the layer, and the present invention is completed. It reached.

That is, according to the present invention,
(1) A first application step of applying a first binder material coating solution to the surface of the base material corresponding to the central part in the width direction of the lithium ion battery electrode active material layer, and the lithium ion battery electrode active material layer A second applying step of applying a second binder coating solution different from the first binder coating solution on the surface of the base material corresponding to both end portions in the width direction, the first binder coating solution and the second binder coating solution (2) a supplying step of supplying a powder containing an electrode active material to the surface of the base material to which the binder coating liquid is applied, and a control step of controlling a coated amount of the powder supplied to the base surface; And forming the active material layer by pressing the powder supplied to the surface of the base material, wherein the tack strength of the binder used in the second binder coating solution is the first one. Greater than the tack strength of the binder used for the binder coating solution, or the solid content concentration of the second binder coating solution is Method for producing a lithium ion battery electrode, wherein the serial greater than the solid concentration of the first binder coating liquid,

(2) The tack strength of the binder used in the second binder coating liquid is 1.5 times or more of the tack strength of the binder used in the first binder coating liquid. (1) The method for producing a lithium ion battery electrode according to (1),

(3) The solid content concentration of the second binder coating liquid is at least 1.3 times the solid concentration of the first binder coating liquid, (1) or (2) described A method of manufacturing an electrode for lithium ion battery,

(4) The width of the end portion in the width direction of the lithium ion battery electrode active material layer is 0.5% to 5% with respect to the width of the lithium ion battery electrode active material layer The manufacturing method of the electrode for lithium ion batteries in any one of (1)-(3),
Is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrode for lithium ion batteries which can maintain the peeling strength of the active material and base material in the width direction both ends of an active material layer highly can be provided.

It is a figure showing an outline of a powder molding device concerning an embodiment of the invention. It is a figure for demonstrating the area | region where the 1st binder coating liquid and 2nd binder coating liquid which concern on embodiment of this invention are apply | coated on the base-material surface. It is a graph which shows the fabric weight of the powder with respect to the active material layer width | variety at the time of 1st binder coating liquid being apply | coated on the surface of a base material. When the 1st binder coating liquid and the 2nd binder coating liquid are applied to the surface of a substrate, it is a graph which shows the area weight of the powder to the active material layer width. It is a figure for demonstrating the other area | region where the 1st binder coating liquid and the 2nd binder coating liquid which concern on embodiment of this invention are apply | coated on the base-material surface.

  Hereinafter, a method of manufacturing an electrode for a lithium ion battery according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an outline of a powder molding apparatus 2 used for manufacturing a lithium ion battery electrode according to an embodiment of the present invention. As shown in FIG. 1, the powder molding device 2 includes a first application unit 6 for applying the first binder coating solution 4, a second application unit 10 for applying the second binder coating solution 8, and a base material. 12, conveying rollers 14A and 14B for conveying 12, a hopper 18 for containing powder 16, a squeegee member 20 for controlling a coated amount of powder 16 supplied from hopper 18 to the surface of substrate 12, and a surface of substrate 12 A pair of press rolls 22A and 22B are provided to press the powder 16 supplied to the

  The first application portion 6 is a first storage tank 6a for storing the first binder coating liquid 4 and a region 12a of the surface of the base 12 corresponding to the widthwise center of the electrode active material layer for a lithium ion battery (see FIG. 2) is provided with a first gravure roll 6b for applying a first binder coating solution 4 thereto. The width of the first gravure roll 6 b is set to the width A (see FIG. 2) of the area 12 a in order to apply the first binder coating liquid 4 to the area 12 a of the substrate 12.

  The second application unit 10 corresponds to the second storage tank 10 a storing the second binder coating solution 8 different from the first binder coating solution 4 and both widthwise end portions of the lithium ion battery electrode active material layer. The second gravure roll 10b is provided to apply the second binder coating liquid 8 to the areas 12b and 12c (see FIG. 2) of the surface of the base material 12. The width of the second gravure roll 10b is set to the width A + B + C (see FIG. 2) of the regions 12a, 12b and 12c of the base 12 corresponding to the width of the lithium ion battery active material layer. Further, the roll diameter at both widthwise end portions of the second gravure roll 10b is larger than the roll diameter at the central portion, and the width of a portion where the roll diameter at one end portion is larger is the width B of the region 12b of the base 12 (see FIG. 2) The width of the portion of the other end where the roll diameter is large is set to the width C (see FIG. 2) of the region 12 c of the base 12. This is because the second binder coating liquid 8 is not applied to the area 12 a of the base 12 but applied only to the areas 12 b and 12 c.

  The squeegee member 20 has a cylindrical shape, and is disposed downstream of the hopper 18 and upstream of the pair of press rolls 22A and 22B. The rotation axis of the squeegee member 20 is parallel to the rotation axes of the pair of pressing rolls 22A and 22B.

  In the case of producing an electrode sheet as a lithium ion battery electrode using this powder molding apparatus 2, first, as shown in FIG. 2, it corresponds to the widthwise central portion of the lithium ion battery electrode active material layer. The first binder coating liquid 4 stored in the first storage tank 6 a of the first application unit 6 is applied to the area 12 a of the base 12. Specifically, the first gravure roll 6b of the first application unit 6 dipped in the first binder coating liquid 4 is applied to the area 12a of the base 12 and rotated to apply the first binder coating liquid 4 Do. Next, as shown in FIG. 2, it is stored in the second storage tank 10 a of the second application unit 10 in the regions 12 b and 12 c of the base 12 corresponding to both widthwise end portions of the lithium ion battery electrode active material layer. The second binder coating liquid 8 is applied. More specifically, the second gravure roll 10b of the second application unit 10 dipped in the second binder coating liquid 8 is brought into contact with the areas 12b and 12c of the surface of the base 12 and rotated, thereby the second binder coating liquid Apply 8 The base 12 having the first binder coating solution 4 applied to the area 12 a and the second binder coating solution 8 applied to the areas 12 b and 12 c reaches the hopper 18 via the transport rollers 14 A and 14 B, and the hopper 18 The powder 16 is then supplied to the surface of the substrate 12. The powder 16 supplied to the surface of the base material 12 is controlled by the squeegee member 20 so that the coating amount is controlled, and it is pressed by passing between the pair of pressing rolls 22A and 22B to form the active material layer 24 . Thereby, an electrode sheet in which the active material layer 24 is compression-formed on the surface of the base 12 is manufactured.

  Here, the substrate 12 may be a thin film-like substrate, and usually has a thickness of 1 μm to 1000 μm, preferably 5 μm to 800 μm. As the substrate 12, metal foil or carbon such as aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, other alloys or the like, conductive polymer, paper, natural fiber, polymer fiber, fabric, polymer resin A film etc. are mentioned and it can select suitably according to the objective. As the polymer resin film, mention may be made of polyester resin films such as polyethylene terephthalate and polyethylene naphthalate, polyimides, polypropylenes, polyphenylene sulfides, polyvinyl chlorides, aramid films, plastic films comprising PEN, PEEK, etc. Be

  Among these, when manufacturing the electrode sheet for lithium ion battery electrodes, metal foil or a carbon film and a conductive polymer film can be used as the base material 12, A metal is used suitably. Among them, copper, aluminum or an aluminum alloy is preferably used in terms of conductivity and voltage resistance. Further, the surface of the substrate 12 may be subjected to treatments such as coating treatment, drilling, buffing, sand blasting and / or etching.

  The first binder coating liquid 4 is not particularly limited as long as it is a compound capable of mutually binding the powder containing the active material and the base material. The first binder coating solution 4 may contain a thickener or a surfactant in order to adjust the viscosity and the wettability of the coating solution. Known thickeners and surfactants can be used. Examples of the binder include SBR aqueous dispersion, acrylate polymer aqueous dispersion, water-based polyacrylic acid (PAA), and organic solvent-based polyvinylidene fluoride (PVDF).

  In addition, the second binder coating solution 8 can be selected from a compound capable of mutually binding the powder containing the active material and the base material in the same manner as the first binder coating solution 4 and the first The binder coating solution 4 is a binder coating solution in which at least one of the binder type, the tack strength of the binder, the solid content concentration and the like is different.

  The first binder coating solution 4 and the second binder coating solution 8 are different binder coating solutions, and the tack strength of the binder used for the second binder coating solution 8 is the first binder coating solution. It is preferable that the tack strength of the binder used for the adhesive coating liquid 4 is 1.5 times or more than that of the binder contained in the first binder coating liquid 4. When the tack strength of the binder increases, the weight per unit area of the powder deposited on the binder coating solution increases, the density of the powder increases, and the adhesion strength of the powder to the substrate increases. It is.

  Alternatively, the solid content concentration of the second binder coating liquid 8 is larger than the solid content concentration of the first binder coating liquid 4 and further 1.3 times or more the solid content concentration of the first binder coating liquid 4 Is preferred. As the solid content concentration of the binder coating liquid increases, the coating weight of the powder deposited on the binder coating liquid increases, the density of the powder increases, and the adhesion strength of the powder to the substrate is increased. It is because it becomes large. The tack strength of the binder used for the second binder coating liquid 8 is larger than the tack strength of the binder used for the first binder coating liquid 4 and the second binder coating liquid 8 The second binder coating solution 8 may be used in which the solid concentration is higher than the solid concentration of the first binder coating solution 4.

  FIG. 3 is a graph showing the coating weight of the powder 16 with respect to the width of the active material layer when only the first binder coating liquid 4 is applied to the regions 12 a, 12 b and 12 c of the substrate 12. FIG. 4 shows the powder with respect to the active material layer width when the first binder coating solution 4 is applied to the area 12 a of the substrate 12 and the second binder coating solution 8 to the areas 12 b and 12 c of the substrate 12. It is a graph which shows a fabric weight of 16. When only the first binder coating liquid 4 is applied to the regions 12a, 12b and 12c of the substrate 12, as shown in the graph of FIG. 3, the coated weight of the powder 16 at both ends in the width direction of the active material layer Is smaller than the coating weight of the powder 16 at the central portion in the width direction. On the other hand, when the first binder coating solution 4 is applied to the area 12 a of the substrate 12 and the second binder coating solution 8 is applied to the areas 12 b and 12 c of the substrate 12, as shown in the graph of FIG. The coating weight of the powder 16 at both end portions in the width direction of the active material layer is larger than the coating weight of the powder 16 at the central portion in the width direction. Therefore, since the adhesive strength of the powder 16 of the both ends of the width direction of an active material layer can be enlarged, it can prevent that the active material layer 24 of both ends peels from the base material 12. FIG.

  On the other hand, when only the second binder coating liquid 8 is applied to the regions 12 a, 12 b and 12 c of the substrate 12, the electrical resistance increases and the coating weight of the powder 16 becomes excessive and passes through the squeegee member 20. At that time, since excessive shearing force is applied to the powder 16, problems such as tearing of the base 12 may occur. Further, the first binder coating solution 4 is applied to the central portion in the width direction of the active material layer, and the second binder coating solution 8 is applied to both end portions in the width direction, thereby suppressing an increase in electrical resistance. Can. Therefore, the shear force applied to the powder 16 when passing through the squeegee member 20 while making the coated weight of the powder 16 at both ends in the width direction of the active material layer larger than the coated weight of the powder 16 in the central part. An appropriate electrode can be manufactured without lowering the production efficiency of the electrode.

  The width of the end in the width direction of the active material layer to which the second binder coating liquid 8 is applied is preferably 0.5% to 5% with respect to the width of the active material layer. The shear force applied to the powder 16 when passing through the squeegee member 20 is appropriately maintained, and the production efficiency of the electrode is not reduced.

  The powder 16 contained in the hopper 18 includes composite particles containing an electrode active material. The composite particles contain an electrode active material and a binder, and may optionally contain other dispersants, conductive materials and additives.

  When the composite particles are used as an electrode material of a lithium ion battery, examples of the positive electrode active material include metal oxides capable of reversibly doping and dedoping lithium ions. Examples of such metal oxides include lithium cobaltate, lithium nickelate, lithium manganate, lithium iron phosphate and the like. In addition, according to a use, the positive electrode active material illustrated above may be suitably used independently, and multiple types may be mixed and used.

  In addition, as an active material of the negative electrode as a counter electrode of the positive electrode for lithium ion batteries, graphitizable carbon, non-graphitizable carbon, low crystalline carbon (amorphous carbon) such as pyrolytic carbon, graphite (natural graphite) , Artificial graphite), alloy materials such as tin and silicon, silicon oxides, tin oxides, oxides such as lithium titanate, and the like. The electrode active materials exemplified above may be used singly or in combination of two or more, depending on the application.

  The shape of the electrode active material for a lithium ion battery electrode is preferably granular. When the shape of the particles is spherical, a denser electrode can be formed at the time of electrode formation.

  The volume average particle diameter of the electrode active material for lithium ion battery electrodes is usually 0.1 to 100 μm, preferably 0.5 to 50 μm, and more preferably 0.8 to 30 μm, for both the positive electrode and the negative electrode.

  The binder used in the composite particles is not particularly limited as long as it is a compound capable of binding the electrode active materials to each other. A preferred binder is a dispersed binder having a property of dispersing in a solvent. Examples of the dispersion-type binder include polymer compounds such as silicon polymers, fluorine-containing polymers, conjugated diene polymers, acrylate polymers, polyimides, polyamides, polyurethanes, etc. Preferably, fluorine-containing polymers are used. Examples thereof include coalescent, conjugated diene polymers and acrylate polymers, more preferably conjugated diene polymers and acrylate polymers.

  The shape of the dispersed binder is not particularly limited, but is preferably in the form of particles. By being in the form of particles, the binding property is good, and it is possible to suppress the decrease in capacity of the manufactured electrode and the deterioration due to the repetition of charge and discharge. Examples of the particulate binder include particles of a binder such as latex dispersed in water, and particulate particles obtained by drying such a dispersion.

  The amount of the binder is dried with respect to 100 parts by weight of the electrode active material from the viewpoint that adhesion between the obtained electrode active material layer and the substrate can be sufficiently secured and internal resistance can be lowered. It is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight on a weight basis.

  In the composite particles, a dispersant may be used as needed as described above. Specific examples of the dispersant include cellulose polymers such as carboxymethyl cellulose and methyl cellulose, and ammonium salts or alkali metal salts of these. These dispersants can be used alone or in combination of two or more.

  For the composite particles, as described above, a conductive material may be used as needed. Specific examples of the conductive material include conductive carbon blacks such as furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Beslothene fennot shap). Among these, acetylene black and ketjen black are preferable. These conductive materials can be used alone or in combination of two or more.

  The composite particles are obtained by granulating using other components such as an electrode active material, a binder, and the above-mentioned conductive material optionally added, and at least comprise an electrode active material and a binder, Each of the above does not exist as individually independent particles, but one particle is formed by two or more components including an electrode active material as a component and a binder. Specifically, a plurality of individual particles of the two or more components are combined to form a secondary particle, and a plurality (preferably several to several tens) of electrode active materials are used as a binder. Preferably, the particles are bound to form particles.

  The method for producing the composite particles is not particularly limited, and the composite particles can be produced by a known granulation method such as a fluidized bed granulation method, a spray drying granulation method, and a rolling bed granulation method.

  The volume average particle diameter of the composite particles is usually in the range of 0.1 to 1000 μm, preferably 1 to 500 μm, more preferably 30 to 250 μm from the viewpoint of easily obtaining an electrode active material layer having a desired thickness.

  The average particle size of the composite particles is a volume average particle size calculated by measurement using a laser diffraction type particle size distribution measuring apparatus (for example, Microtrac MT3300EX II; Nikkiso).

  According to the method of manufacturing a lithium ion battery electrode according to this embodiment, region 12a of base 12 corresponding to the central portion in the width direction of the lithium ion battery electrode active material layer using powder forming apparatus 2 The first binder coating solution 4 is applied to the first layer 12 and the second binder coating solution 8 is applied to the regions 12b and 12c of the base 12 corresponding to both end portions in the width direction of the lithium ion battery electrode active material layer. . That is, in order to apply the second binder coating liquid 8 with high tack strength and high solid content concentration to the regions 12 b and 12 c of the base material 12 corresponding to both end portions in the width direction of the lithium ion battery electrode active material layer, The coating weight of the powder 16 deposited in the regions 12a and 12b can be increased. Therefore, the peeling strength between the active material layer 24 and the base 12 at both ends in the width direction of the active material layer can be maintained high, and the active material layers 24 at both ends in the width direction peel from the surface of the base 12 Can be prevented.

  In the above embodiment, the first binder coating solution 4 is applied to the region 12a of the base 12 and the second binder coating solution 8 is applied to the regions 12b and 12c of the base 12 (see FIG. 2). , 1 row of electrodes are manufactured, for example, as shown in FIG. 5, the second binder coating liquid is applied to the regions 12d and 12e at both widthwise end portions of the base 12 and the region 12f at the widthwise center portion 8 may be applied, and the first binder coating liquid 4 may be applied to the areas 12g and 12h other than the areas 12d, 12e and 12f to manufacture two lines of electrodes. In this case, after completion of the powder forming in the powder forming device 2, two electrodes are manufactured by cutting at the position of the broken line L shown in FIG.

  The tack strength of the binder used for the binder coating solution (first binder coating solution and second binder coating solution) used in the following examples and comparative examples is the measurement result by the probe tack method. Is due to A binder used for a binder coating solution (first binder coating solution and second binder coating solution) in an atmosphere at 25 ° C. using a tacking tester (TAC-1000: made by Lesca) The probe tack to the SUS probe (10 mmφ) was measured to obtain the tack strength (N / 10 mmφ) of the binder.

Example 1
Using the powder molding apparatus 2 shown in FIG. 1, a first binder coating liquid having a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% corresponds to the central portion in the width direction of the active material layer. On the surface of the material, a second binder coating solution with a tack strength of 4.2 N / 10 mmφ and a solid content concentration of 30% is applied to both ends in the width direction of the active material layer (the end in the width direction of the active material layer is the active material) It apply | coated to the base-material surface corresponding to 2% of the width | variety of layer, and obtained the electrode sheet. The adhesive strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance (here, “low temperature” means low temperature (for example, −30 ° C. to normal temperature (25 ° C.)) are shown in Table 1.

(Example 2)
Using the powder molding apparatus 2 shown in FIG. 1, a first binder coating liquid having a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% corresponds to the central portion in the width direction of the active material layer. On the surface of the material, a second binder coating solution with a tack strength of 2.3 N / 10 mmφ and a solid content concentration of 30% is applied to both ends in the width direction of the active material layer (the end in the width direction of the active material layer is the active material) It apply | coated to the base-material surface corresponding to 2% of the width | variety of layer, and obtained the electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Example 3)
Using the powder molding apparatus 2 shown in FIG. 1, a first binder coating liquid having a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% corresponds to the central portion in the width direction of the active material layer. On the surface of the material, a second binder coating solution with a tack strength of 1.5 N / 10 mmφ and a solid content concentration of 46% is applied to both ends in the width direction of the active material layer (the end in the width direction of the active material layer is the active material) It apply | coated to the base-material surface corresponding to 2% of the width | variety of layer, and obtained the electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Example 4)
Using the powder molding apparatus 2 shown in FIG. 1, a first binder coating liquid having a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% corresponds to the central portion in the width direction of the active material layer. On the surface of the material, a second binder coating solution with a tack strength of 1.5 N / 10 mmφ and a solid content concentration of 40% is applied to both ends in the width direction of the active material layer (the end in the width direction of the active material layer is the active material) It apply | coated to the base-material surface corresponding to 2% of the width | variety of layer, and obtained the electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Example 5)
Using the powder molding apparatus 2 shown in FIG. 1, a first binder coating liquid having a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% corresponds to the central portion in the width direction of the active material layer. On the surface of the material, a second binder coating solution with a tack strength of 3.5 N / 10 mmφ and a solid content concentration of 30% is applied to both ends in the width direction of the active material layer (the end in the width direction of the active material layer is the active material) It apply | coated to the base-material surface corresponding to 8% of the width | variety of layers, and obtained the electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Comparative example 1)
Using the powder molding apparatus 2 shown in FIG. 1, a binder coating solution with a tack strength of 1.5 N / 10 mm and a solid content concentration of 30% was applied to the surface of a substrate to obtain an electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Comparative example 2)
Using the powder molding apparatus 2 shown in FIG. 1, a binder coating solution having a tack strength of 4.2 N / 10 mm and a solid content concentration of 30% was applied to the surface of a substrate to obtain an electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

(Comparative example 3)
Using the powder molding apparatus 2 shown in FIG. 1, a binder coating solution having a tack strength of 1.5 N / 10 mm and a solid content concentration of 45% was applied to the surface of a substrate to obtain an electrode sheet. The adhesion strength at both ends of the active material layer, the production efficiency of the electrode sheet and the low temperature reaction resistance are shown in Table 1.

  T1 is the tack strength of the binder contained in the first binder coating liquid, T2 is the tack strength of the binder contained in the second binder coating liquid, and C1 is the solid content of the first binder. The concentration, C2, is the solid concentration of the second binder. Further, as a result of the adhesive strength at the end, A indicates that the adhesive strength is high, B indicates that the adhesive strength is lower than A, and D indicates that the adhesive strength is lower than B. Production efficiency results O show high production efficiency, X shows low production efficiency, low temperature reaction resistance results A show low resistance, B shows higher resistance than A.

  As described above, as shown in the results of Examples and Comparative Examples shown in Table 1, when the binder coating solution with high tack strength or high solid content concentration is applied to both ends in the width direction of the electrode sheet, high production efficiency and It is possible to obtain an electrode sheet in which the peel strength between the active material layer and the substrate at the end is maintained high while maintaining low resistance, that is, an electrode sheet in which the active material layer at the edge is less likely to peel from the substrate.

  2 powder forming apparatus, 4 first binder coating solution, 6 first coating unit, 6 a first reservoir, 6 b first gravure roll, 8 second binder coating solution, 10 Second application unit, 10a: second storage tank, 10b: second gravure roll, 12: base material, 14a, 14b: transport roller, 16: powder, 18: hopper, 20: squeegee member, 22A, 22B: press Roll, 24 ... active material layer.

Claims (3)

A first application step of applying a first binder coating solution to the surface of the base material corresponding to the center in the width direction of the lithium ion battery electrode active material layer;
A second application step of applying a second binder coating solution different from the first binder coating solution on the surface of the substrate corresponding to both end portions in the width direction of the lithium ion battery electrode active material layer;
Supplying a powder containing an electrode active material to the surface of the substrate to which the first binder coating solution and the second binder coating solution have been applied;
A control step of controlling a coated amount of the powder supplied to the surface of the substrate;
A forming step of forming an active material layer by pressing the powder supplied to the surface of the base material using a pair of pressing rolls;
Including
The tack strength of the binder used in the second binder coating liquid is greater than the tack strength of the binder used in the first binder coating liquid, or the solid content of the second binder coating liquid The concentration is higher than the solid content concentration of the first binder coating solution ,
The width of the end in the width direction of the lithium ion battery electrode active material layer is 0.5% or more and 5% or less with respect to the width of the lithium ion battery electrode active material layer,
In the control step, a coated amount of the powder is controlled by a squeegee member .   The tack strength of the binder used in the second binder coating liquid is 1.5 or more times the tack strength of the binder used in the first binder coating liquid. The manufacturing method of the electrode for lithium ion batteries of the claim | item 1 statement. The lithium ion according to claim 1 or 2, wherein a solid content concentration of the second binder coating liquid is 1.3 times or more of a solid content concentration of the first binder coating liquid. Method of manufacturing battery electrode.

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