Electrode manufacturing method

Abstract

To provide a method of manufacturing an electrode using a granulated material with improved spreadability.SOLUTION: A method of manufacturing an electrode includes the steps of: preparing a granulated material 10 containing an electrode active material, a binder, and a solvent; compressing the granulated material between a pair of rolls 31, 32, to form an electrode composite layer 12; and placing the electrode composite layer on an electrode current collector 13. At least one of the pair of rolls has a temperature of 40°C. or higher.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electrode. [Background technology]

[0002] For example, Patent Document 1 (JP 2018-032604 A) discloses a method for producing an electrode, in which a sheet-like electrode for use in a lithium-ion secondary battery or the like is produced by preparing granules containing an electrode mixture, molding the granules, and disposing an electrode mixture layer on an electrode current collector (granule molding method). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-032604 Summary of the Invention [Problem to be solved by the invention]

[0004] When producing electrodes by granulation molding, further improvement in productivity is required. To improve productivity, it is desirable to improve the malleability of the granules.

[0005] Therefore, an object of the present disclosure is to provide a method for manufacturing an electrode using a granulated body with improved malleability. [Means for solving the problem]

[0006] [1] The method for manufacturing an electrode according to the present disclosure includes: preparing granules containing an electrode active material, a binder, and a solvent; a step of compressing and molding the granules with a pair of rolls to form an electrode mixture layer; and placing the electrode mixture layer on an electrode current collector, At least one of the pair of rolls has a temperature of 40° C. or higher.

[0007] According to the manufacturing method [1] above, an electrode can be manufactured using granules with improved malleability.

[0008] That is, the viscosity of the binder dissolved in the solvent contained in the granules is reduced by heating the granules when they are compression-molded between a pair of rolls, at least one of which has a temperature of 40° C. or higher. This increases the area of ​​the surface of the electrode active material in the granules that is wetted with the solvent (or a mixed solution of the solvent and the binder), thereby improving the spreadability of the electrode active material.

[0009] [2] In the electrode manufacturing method of the present disclosure, the temperature of the pair of rolls is preferably 40°C or higher.

[0010] By setting the temperature of both of the pair of rolls to 40°C or higher, the granules are efficiently heated.

[0011] [3] In the electrode manufacturing method of the present disclosure, the solid content of the granules is preferably 75% by mass or more and 90% by mass or less.

[0012] In this case, the granules have good spreadability and liquid retention, making it easy to manufacture electrodes using the granules, and improving the productivity in electrode manufacturing. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a flowchart showing an outline of a method for manufacturing an electrode according to an embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing an apparatus used to manufacture an electrode in the embodiment. [Figure 3] FIG. 3 is a schematic perspective view showing an apparatus used to manufacture an electrode in the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of an electrode sheet. [Figure 5] FIG. 5 is a graph showing the relationship between the solid content and the spreadability and liquid retention of the granules of the comparative examples. [Figure 6] FIG. 6 is a graph showing the relationship between the solid content and the spreadability and liquid retention for the granules of the Examples and Comparative Examples. [Figure 7] FIG. 7 is a schematic diagram showing a measuring device for measuring the spreadability evaluation value. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present disclosure will be described. However, the present disclosure is not limited thereto. In this specification, the "positive electrode" and the "negative electrode" will be collectively referred to as "electrodes."

[0015] Fig. 1 is a flowchart showing an outline of the method for producing an electrode according to the present embodiment. As shown in Fig. 1, the method for producing an electrode according to the present embodiment includes at least a granule preparation step (S10), an electrode mixture layer formation step (S20), and an arrangement step (S30).

[0016] The electrode manufactured in this embodiment is, for example, a sheet-shaped electrode (electrode sheet) for a lithium ion secondary battery. The electrode may be either a positive electrode or a negative electrode.

[0017] Granule preparation step (S10) In the granule preparation step, granules (wet granules) containing an electrode active material, a binder, and a solvent are prepared. The granules are an aggregate of a plurality of granulated particles (composite particles) containing the electrode active material, a binder, and a solvent.

[0018] The granules can be prepared, for example, by mixing (granulating) an electrode active material, a binder, a solvent, etc. As a granulation method, for example, an agitation granulation method can be used. Examples of various granulation procedures used in the granule preparation step include agitation granulation, fluidized bed granulation, and tumbling granulation. Various granulation devices such as an agitation mixer can be used for these granulation procedures. When the agitation mixer has an agitation blade (rotor blade), the rotation speed of the agitation blade is, for example, about 200 to 5000 rpm.

[0019] (Electrode active material) The electrode active material may be a positive electrode active material or a negative electrode active material. The electrode active material may be in a particulate form or may be porous active material particles formed by aggregation of primary particles composed of the electrode active material.

[0020] Examples of the positive electrode active material include lithium-containing metal oxides, lithium-containing phosphates, etc. Examples of the lithium-containing metal oxides include LiCoO2, LiNiO2, the compound represented by the general formula LiNi a Co b O2 (where a + b = 1, 0 < a < 1, 0 < b < 1 in the formula), LiMnO2, LiMn2O4, the compound represented by the general formula LiNi a Co b Mn c O2 (where a + b + c = 1, 0 < a < 1, 0 < b < 1, 0 < c < 1 in the formula), LiFePO4, etc. Here, examples of the compound represented by the general formula LiNi a Co b Mn c O2 include, for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc. Examples of the lithium-containing phosphates include LiFePO4, etc.

[0021] The average particle size of the positive electrode active material may be, for example, about 1 to 25 μm. Here, the "average particle size" means the particle size (D50) at the integrated value of 50% in the volume-based particle size distribution measured by the laser diffraction / scattering method.

[0022] Examples of the negative electrode active material include carbon-based negative electrode active materials such as graphite, easily graphitizable carbon, and hardly graphitizable carbon, and alloy-based negative electrode active materials containing silicon (Si), tin (Sn), etc. The average particle size (D50) of the negative electrode active material particles may be, for example, about 1 to 25 μm.

[0023] The blending ratio of the electrode active material to the total amount of solid content of the granules (ie, the content of the electrode active material in the electrode mixture layer) is, for example, about 94 to 99.7 mass %.

[0024] (binder) Examples of binders include carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), etc. One type of binder may be used alone, or two or more types may be used in combination.

[0025] The blending ratio of the binder to the total amount of solid content of the granules (ie, the content of the binder in the electrode mixture layer) is, for example, about 0.3 to 6 mass %.

[0026] (solvent) Examples of the solvent include an aqueous solvent, an organic solvent, etc. An aqueous solvent means water or a mixed solvent containing water and a polar organic solvent.

[0027] As the aqueous solvent, water is preferably used because of its ease of handling. Examples of polar organic solvents that can be used in the mixed solvent include alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone, and ethers such as tetrahydrofuran. The aqueous solvent can be preferably used as a solvent for producing the negative electrode.

[0028] Examples of organic solvents include N-methyl-2-pyrrolidone (NMP). The organic solvent can be suitably used as a solvent for producing the positive electrode.

[0029] The amount of solvent used is not particularly limited, but the solid content (non-volatile content) of the granules is preferably 75 to 90 mass %, more preferably 80 to 86 mass %, and even more preferably 82 to 84 mass %. In this case, the liquid retention of the granules is good, and the electrode mixture layer 12 can be more reliably transferred to the electrode current collector 13 on the third roll 33 in the arrangement step (S30) described below. The "solid content" refers to the ratio of the mass of components other than the solvent (non-volatile components) to the total mass of all raw materials including the solvent.

[0030] Furthermore, in this case, the granules have good spreadability and good liquid retention, making it easy to manufacture electrodes using the granules, and improving the productivity in electrode manufacturing.

[0031] In the past, in order to obtain granules having both the desired spreadability and liquid retention properties in order to improve the productivity of electrode production, adjustments to the types and blending ratios of materials constituting the granules have been considered, but it has been difficult to obtain granules having both the desired spreadability and liquid retention properties through such adjustments.

[0032] Specifically, the malleability of the granules required for easy electrode production is, for example, that the malleability evaluation value (see Examples below) be equal to or less than a specific threshold value (220 μm). This threshold value for the malleability evaluation value was determined from the results of actually producing electrodes using granules with various malleabilities, and is a threshold value that prevents unevenness (non-uniformity) and gaps (defects) from occurring in the electrode mixture layer provided on the electrode current collector.

[0033] Furthermore, the liquid retention properties of the granules necessary for easy electrode production include, for example, an exudation rate (see Examples below) of not more than a specific threshold value (5% by mass). This exudation rate threshold was determined from the results of actual electrode production using granules with various ductility properties, and is the threshold value for ensuring sufficient adhesion of the electrode mixture layer to the electrode current collector.

[0034] FIG. 5 is a graph showing the relationship between the solid content and the spreadability evaluation value and exudation rate for conventional (unheated) granules (the granules of Comparative Examples 1 to 8 described below). Referring to FIG. 5, the solid content of the granules at which the spreadability evaluation value of the granules is equal to or less than the threshold value (220 μm) is less than approximately 81%. On the other hand, the solid content of the granules at which the liquid retention of the granules is equal to or less than the threshold value (5% by mass) is equal to or more than approximately 82% by mass. This shows that it is difficult to obtain granules that satisfy both the spreadability (spreadability evaluation value) and liquid retention (exudation rate) required for easy electrode production simply by adjusting the material composition of conventional granules.

[0035] In contrast, by heating the granules of this embodiment in the electrode mixture layer forming step described below, it is possible to obtain granules that have both good spreadability and good liquid retention, which can facilitate electrode production and improve productivity (see the Examples described below, particularly Examples 6 and 7 indicated by white triangles in FIG. 6 ).

[0036] (Other ingredients) The granules may contain other components than those mentioned above, such as a conductive material. Examples of the conductive material include carbon black such as acetylene black (AB), thermal black, and furnace black. The conductive material is expected to improve electronic conductivity.

[0037] 《Electrode composite material layer formation process (S20)》 In the electrode mixture layer forming step, the granules are compression-molded with a pair of rolls to form an electrode mixture layer. For example, the granules obtained in the granule preparation step are supplied between a pair of rolls that are arranged parallel to each other at a distance from each other and are driven to rotate, and the granules are compression-molded with the pair of rolls to form an electrode mixture layer. Specifically, as shown in Figures 2 and 3, granules 10 are supplied between a first roll 31 and a second roll 32 (first gap), and the granules 10 are compression-molded to form an electrode mixture layer 12.

[0038] The electrode manufacturing method of this embodiment uses an electrode manufacturing apparatus 3 as shown in Figures 2 and 3. The electrode manufacturing apparatus 3 includes a feeder 2 and three rolls (a first roll 31, a second roll 32, and a third roll 33). The diameter of each of the first roll 31, the second roll 32, and the third roll 33 is, for example, 10 to 1000 mm, and the length in the axial direction of each is, for example, 100 to 2000 mm.

[0039] The first roll 31, the second roll 32, and the third roll 33 have their respective rotation axes fixed so that they are parallel to one another. The distance (width) between the first roll 31 and the second roll 32 (first gap) is maintained constant. The distance of the second gap between the second roll 32 and the third roll 33 is also maintained constant. The first roll 31, the second roll 32, and the third roll 33 are each driven to rotate. In Figures 2 and 3, the curved arrows drawn on each roll indicate the rotation direction of each roll.

[0040] The first roll 31 and the second roll 32 are driven to rotate in opposite directions to each other. Granulated material is supplied between this pair of rolls (first roll 31 and second roll 32) and compressed and molded by the pair of rolls to form a sheet-like electrode mixture layer.

[0041] The temperature of at least one of the pair of rolls is 40°C or higher. That is, the temperature of at least one of the first roll 31 and the second roll 32 is 40°C or higher. By using such rolls, the granules are heated during compression molding, and the viscosity of the binder dissolved in the solvent contained in the granules is reduced. When the viscosity of the binder is reduced, the area of ​​the surface of the electrode active material in the granules that is wetted with the solvent (or a mixture of the solvent and the binder) increases. Therefore, the spreadability of the electrode active material is improved. Note that the temperature of the rolls means the temperature of the roll surface.

[0042] It is also preferable that the temperatures of both of the pair of rolls are 40°C or higher. That is, it is preferable that the temperatures of both the first roll 31 and the second roll 32 are 40°C or higher. In this way, the granules are heated efficiently. The temperature of the third roll 33 may also be 40°C or higher.

[0043] The temperature of the rolls is preferably 50° C. or higher, and more preferably 70° C. or higher. The temperature of the rolls may be 120° C. or lower, or may be 100° C. or lower.

[0044] The means for heating the roll is not particularly limited, and may be, for example, a heater, etc. Examples of the heater include an infrared heater (IR heater), an electric heater, etc.

[0045] The first gap distance is, for example, about 50 μm to 10 mm. The first gap distance is the linear distance between the first roll 31 and the second roll 32 at the position where the first roll 31 and the second roll 32 are closest to each other.

[0046] The feeder 2 is disposed directly above the gap (first gap) between the first roll 31 and the second roll 32. In this step, first, the granules are fed to the feeder 2. The feeder 2 feeds the granules 10 into the first gap.

[0047] The electrode manufacturing apparatus 3 further includes a pair of regulating plates 24 arranged parallel to each other at a predetermined distance in the axial direction of the first roll 31 and the second roll 32. The pair of regulating plates 24 regulate the width of the granules 10 supplied to the first gap. As the first roll 31 and the second roll 32 rotate (in the direction of the arrow in the figure), the granules 10 are drawn downward into the first gap and pass through the first gap. This allows the weight per unit area (mass per unit area) of the electrode mixture layer 12 to be adjusted. The pair of regulating plates 24 also allows exposed portions 13a, where the electrode mixture layer 12 is not disposed, to be formed at both ends of the electrode current collector 13 in the width direction (FIG. 4). The weight per unit area of ​​the electrode mixture layer 12 can also be adjusted by the distance of the first gap.

[0048] The rotation speed of second roll 32 is preferably faster than that of first roll 31. For example, the rotation speed of second roll 32 is about three to five times faster than that of first roll 31. By making the rotation speed of second roll 32 faster than that of first roll 31, as shown in FIG. 2 , the granules are stretched more on the surface of second roll 32 than on the surface of first roll 31, and the area of ​​the liquid bridge portion of the granules in contact with the surface of second roll 32 becomes larger than the area in contact with the surface of first roll 31. As a result, granules 10 (electrode mixture layer 12) after rolling adhere to the second roll 32 side and are transported by second roll 32.

[0049] 《Placement process (S30)》 In the disposing step, the electrode mixture layer 12 is disposed on the electrode current collector 13. For example, the electrode mixture layer 12 is disposed on the electrode current collector 13 by transferring the sheet-like electrode mixture layer 12 produced in the electrode mixture layer forming step (S20) to the electrode current collector 13 (negative electrode current collector).

[0050] More specifically, as shown in Figures 2 and 3, electrode current collector 13 is transported on third roll 33 and supplied between second roll 32 and third roll 33 (second gap). After leaving between first roll 31 and second roll 32 (first gap), electrode mixture layer 12 is transported on second roll 32 and supplied to the second gap. Second roll 32 and third roll 33 are driven to rotate in opposite directions (see curved arrows in Figures 2 and 3).

[0051] In the gap between the second roll 32 and the third roll 33, the electrode mixture layer 12 is pressed against the electrode current collector 13, and the electrode mixture layer 12 is separated from the second roll 32 and pressed against the electrode current collector 13. That is, the electrode mixture layer 12 is transferred from the second roll 32 to the electrode current collector 13. In this way, the electrode mixture layer 12 transported on the second roll 32 and the electrode current collector 13 transported on the third roll 33 are supplied between the second roll 32 and the third roll 33 (second gap), whereby the electrode mixture layer 12 is disposed on the electrode current collector 13.

[0052] After the electrode mixture layer 12 is dried, the electrode sheet 11 may be cut to a predetermined size using, for example, a slitter.

[0053] An electrode obtained by the manufacturing method of the present disclosure can be used as an electrode for a secondary battery such as a lithium ion secondary battery (nonaqueous electrolyte secondary battery). A secondary battery such as a lithium ion secondary battery can be used as a power source for a hybrid vehicle (HV), an electric vehicle (EV), a plug-in hybrid vehicle (PHV), etc. However, the electrode obtained by the manufacturing method of the present disclosure is not limited to such in-vehicle applications and can be applied to a variety of applications. [Example]

[0054] The present embodiment will be described below using examples, but the present embodiment is not limited to these.

[0055] Example 1 The electrode (positive electrode) of Example 1 was produced as follows.

[0056] <Granule production process> In Example 1, first, the following materials are prepared.

[0057] Positive electrode active material: NCM (nickel cobalt manganese oxide lithium) [average particle size (D50): 6 μm] Binder: Polyvinylidene fluoride (PVDF) The positive electrode active material (95 parts by mass), auxiliary agent (AB: 3.5% by mass), binder (1.5 parts by mass), and solvent (NMP) were charged into the stirring tank of a mixer (stirring granulator) and mixed to produce granules. The amount of solvent used was adjusted so that the solid content of the granules was 77% by mass.

[0058] To achieve a coating thickness of 4 μm, the target particle size of the granules is set to an average particle size (D90) of 4 mm (100 times the coating thickness), with the goal of obtaining granules with a D90 of 4 mm or less. Note that D90 refers to the particle size at 90% cumulative in the volume-based particle size distribution measured using the laser diffraction / scattering method.

[0059] 《Electrode composite material layer formation process》 In this step, a sheet-like electrode mixture layer 12 (positive electrode mixture layer) was formed from the granules using the electrode manufacturing apparatus 3 shown in Figures 2 and 3, as in the above-described embodiment. In the electrode manufacturing apparatus 3, the first roll 31 and the second roll 32 were heated to 40°C by an IR heater.

[0060] In the electrode manufacturing apparatus 3, the distance between the first roll 31 and the second roll 32 (first gap distance) is 50 μm. The distance between the second roll 32 and the third roll 33 (second gap distance) is 20 μm. The diameter of each of the first roll 31, the second roll 32, and the third roll 33 is all 100 mm, and the length of each is all 200 mm.

[0061] 《Placement process》 In this step, as in the above-described embodiment, each of the electrode mixture layers 12 is placed on an electrode current collector 13 using an electrode manufacturing apparatus 3 shown in FIGS. 2 and 3. The electrode current collector 13 (positive electrode current collector) is an aluminum (Al) foil (thickness: 12 μm). The electrode mixture layer is dried to produce the electrode (positive electrode) of Example 1.

[0062] Examples 2 to 8 In Examples 2 to 8, the solid content concentrations of the granules in the granule preparation step were adjusted to 78, 79, 80, 81, 82, 83, and 84 mass%, respectively. Except for this, the electrodes of Examples 2 to 8 were produced in the same manner as in Example 1.

[0063] Comparative Examples 1 to 8 In Comparative Examples 1 to 8, the first roll 31 and the second roll 32 were not subjected to a heating treatment. Except for this, the electrodes of Comparative Examples 1 to 8 were produced in the same manner as in Examples 1 to 8, respectively.

[0064] <Ductility evaluation> The malleability was evaluated for the electrodes of Examples 1 to 8 and Comparative Examples 1 to 8. Specifically, the malleability was evaluated as follows using a malleability evaluation device 60 shown in Fig. 7.

[0065] As shown in Fig. 7, a malleability evaluation device 60 has a load cell-mounted table 61. An upper plate 62 is fixed to the load cell-mounted table 61 via supports 63, 63. A lower wedge member 64 and an upper wedge member 65 are placed on the load cell-mounted table 61. The lower wedge member 64 and the upper wedge member 65 each have a slope at a predetermined angle, and are stacked such that the slope of the lower wedge member 64 faces the slope of the upper wedge member 65. Furthermore, a lower moving plate 66 is installed on the upper wedge member 65 in a state where it is integrated with the upper wedge member 65.

[0066] Then, using a movement mechanism (not shown), the rotation shaft 67 is rotated with a handle 68 to move the upper wedge member 65 and the lower movable plate 66 to the left in the figure, and the upper wedge member 65 and the lower movable plate 66 therefore move along the slope of the lower wedge member 64 and therefore also move upward. That is, when the lower movable plate 66 moves a predetermined distance to the left in the figure, it also rises a predetermined height in the upward direction in the figure. Note that in the spreadability evaluation device 60 used in the examples, the angles of the slopes of the lower wedge member 64 and the upper wedge member 65 are set so that when the lower movable plate 66 is moved 15 mm to the left in the figure (horizontally), the lower movable plate 66 rises 40 μm upward.

[0067] When evaluating the electrodes, first, the electrode mixture layer (aggregate of granules) was removed from each of Examples 1 to 8 and Comparative Examples 1 to 8. Then, 0.5 g of the removed aggregate of granules was placed on the lower movable plate 66 of the spreadability evaluation device 60. Then, the handle 68 was rotated to move the lower movable plate 66 leftward in the figure at a speed of 15 mm / sec and upward at a speed of 40 μm / sec. As a result, the granules on the lower movable plate 66 were spread and formed into a granule film 5 while a shear force was applied between the upper plate 62 and the lower movable plate 66.

[0068] During spreading, a reaction force of the spreading of the granule film 5 is applied to the load cell-equipped platform 61 via the lower movable plate 66, the upper wedge member 65, and the lower wedge member 64, and this reaction force is measured as a load L. In addition, the upper plate 62 is provided with a displacement sensor 69 that measures the distance between the upper plate 62 and the lower movable plate 66, i.e., the thickness T of the granule film 5.

[0069] For the examples and comparative examples, when the upper wedge member 65 and the lower movable plate 66 were moved leftward in the drawing as described above, the thickness T (μm) of the granule film 5 when the load L reached 6.5 kN was measured as the spreadability evaluation value. Note that the smaller the spreadability evaluation value (μm), the higher the spreadability of the granules (the easier they were to spread).

[0070] The measurement results of the ductility evaluation values ​​(μm) of the examples and comparative examples are shown in FIG.

[0071] <Liquid retention evaluation> For the granules of Comparative Examples 1 to 8, the exudation rate (mass %) when the granules were compressed was measured as an index of liquid retention. The exudation rate (mass %) is the proportion of the amount of solvent that exuded when the granules were compressed to a density of 1.6 g / cc by pressure using a hydraulic press. The exudation rate was calculated using the following formula. ("Amount of solvent contained in granules before compression" - "Amount of solvent contained in granules after compression") / "Amount of solvent contained in granules before compression") The smaller the exudation rate (mass %), the higher the liquid retention of the granules.

[0072] The measurement results of the exudation rates (mass%) of the granules of Comparative Examples 1 to 8 are shown in Figure 6. Note that, since the liquid retention capacity is determined mainly by the solid content of the granules, the liquid retention capacity of each of the granules of Examples 1 to 8 is considered to be similar to that of each of the granules of Comparative Examples 1 to 8.

[0073] From the results shown in FIG. 6, it can be seen that the granules of Examples 1 to 8 have improved spreadability compared to the granules of Comparative Examples 1 to 8.

[0074] Furthermore, as described above with reference to Fig. 5, it was difficult to obtain granules that satisfied both the ductility and liquid retention properties required for facilitating the production of electrodes simply by adjusting the material composition of the conventional (comparative) granules. In contrast, the granules of the Examples have improved ductility while maintaining liquid retention, making it possible to obtain granules that have both good ductility and good liquid retention properties, which facilitate the production of electrodes and improve productivity (see Examples 6 and 7, indicated by white triangles in Fig. 6).

[0075] The embodiments and examples disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0076] 10 Granules, 11 Electrode sheet, 12 Electrode mixture layer, 13 Electrode current collector, 13a Exposed portion, 2 Feeder, 24 Regulating plate, 3 Electrode manufacturing device, 31 First roll, 32 Second roll, 33 Third roll, 33a Convex portion, 33b Concave portion, 4 Blade, 5 Granule film, 60 Spreadability evaluation device, 61 Base with load cell, 62 Upper plate, 63 Support, 64 Lower wedge member, 65 Upper wedge member, 66 Lower moving plate, 67 Rotating shaft, 68 Handle, T Thickness (of granule film), L Load.

Claims

1. A method for manufacturing an electrode using an electrode manufacturing apparatus having a pair of rolls, a first roll and a second roll, and a third roll, preparing granules containing an electrode active material, a binder, and a solvent; a step of compressing and molding the granules with the pair of rolls to form an electrode mixture layer; and supplying the electrode mixture layer and the electrode current collector between the second roll and the third roll to dispose the electrode mixture layer on the electrode current collector, The temperature of the pair of rolls is 40°C or higher and 100°C or lower, The solid content of the granules is 82% by mass or more and 83% by mass or less, The method for manufacturing an electrode, wherein the binder includes polyvinylidene fluoride.

2. A method for manufacturing an electrode as described in claim 1, wherein the rotation speed of the second roll is faster than the rotation speed of the first roll.

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