Electrode manufacturing method, manufacturing system, and electrode

Abstract

To improve shape precision at the edge of an active material film.SOLUTION: A method for manufacturing an electrode includes the following steps (a) to (c): the step (a) of preparing a substrate sheet; the step (b) of preparing an active material film; and the step (c) of pasting the active material film to the substrate sheet by passing the substrate sheet and the active material film through a nip between rolls. The substrate sheet includes a first region and a second region. The second region has a larger arithmetic mean roughness than the first region. The second region is adjacent to the first region. In the step (c), the active material film is selectively attached to the first region of the first and second regions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Japanese Patent Application Laid-Open Publication No. 2012-228649 (Patent Document 1) discloses a coating device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-228649 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, an electrode includes a substrate sheet and an active material film. The active material film may also be referred to as an "active material layer" or "composite layer," for example. The active material film is attached to the substrate sheet.

[0005] The electrode may include a coated portion and a non-coated portion. The coated portion refers to a portion of the surface of the substrate sheet where an active material film is disposed. The non-coated portion refers to a portion of the surface of the substrate sheet where an active material film is not disposed. The non-coated portion is adjacent to the coated portion. The non-coated portion can be used, for example, to connect the substrate sheet to a current collecting member.

[0006] The shape of the active material film tends to be easily distorted at the boundary between the coated and non-coated areas (i.e., the edge of the active material film) because the operation of the coating device is intermittent. A coating method in which coated and non-coated areas are formed alternately can also be called intermittent coating.

[0007] A method has also been proposed in which coated and uncoated areas are formed by continuous coating. That is, a mask is attached to a portion of a substrate sheet in advance. An active material film is formed continuously over the entire surface of the substrate sheet. The uncoated areas can be formed by peeling off the mask and the active material film formed on the mask.

[0008] However, considering that the mask will be peeled off later, it is necessary to adjust the mask so that it does not adhere too closely to the substrate sheet. As a result, a gap may be formed between the mask and the substrate sheet. If the paint (active material) penetrates into the gap, the shape of the edge of the active material film may be distorted. Furthermore, if the edge of the active material film is damaged when the mask is peeled off, the shape may be distorted.

[0009] The present disclosure aims to improve the shape accuracy of the edge of an active material film. [Means for solving the problem]

[0010] The technical configuration and effects of the present disclosure will be described below. However, the mechanism of action in this specification includes speculation. The mechanism of action does not limit the technical scope of the present disclosure.

[0011] 1. The method for producing an electrode includes the following steps (a) to (c): (a) Prepare a substrate sheet. (b) An active material film is prepared. (c) The substrate sheet and the active material film are passed through a nip between rolls to attach the active material film to the substrate sheet. The substrate sheet includes a first region and a second region. The second region has a larger arithmetic mean roughness than the first region. The second region is adjacent to the first region. In (c) above, the active material film is selectively attached to the first region out of the first and second regions.

[0012] The substrate sheet includes a first region (smooth surface) and a second region (rough surface). The rough surface has a larger arithmetic mean roughness (surface roughness) than the smooth surface. According to the new findings of the present disclosure, the active material film can selectively adhere to the smooth surface. This is thought to be because differences in surface roughness can cause differences in contact area and adhesive strength. By selectively adhering the active material film to the smooth surface, improved shape accuracy is expected at the edge of the active material film (the boundary between the smooth surface and the rough surface). Furthermore, elimination of the mask is expected to simplify the process and reduce costs.

[0013] 2. In the method for manufacturing an electrode according to the above item "1," the ratio of the arithmetic mean roughness of the second region to the arithmetic mean roughness of the first region may be, for example, 100 or more.

[0014] Hereinafter, the "ratio of the arithmetic mean roughness of the second region to the arithmetic mean roughness of the first region" will also be referred to as the "roughness ratio." A roughness ratio of 100 or more is expected to improve shape accuracy.

[0015] 3. In the method for producing an electrode according to the above item "1" or "2," the above item (b) may include, for example, the following items (b1) and (b2): (b1) A wet powder containing an active material and a binder is prepared. (b2) Forming the wet powder into an active material film.

[0016] Possible coating materials (precursors of active material films) include slurries, wet powders, dry powders, etc. Slurries refer to a dispersion system in which powder (solid) is dispersed in a dispersion medium (liquid). Wet powders refer to a dispersion system in which droplets (liquid) are dispersed in powder (solid). Dry powders contain substantially no liquid. Slurries are liquid. Because slurries have high fluidity, they tend to easily cause shape changes (dripping) at the edges of the coating film. Wet powders are powder-like. Wet powders tend to have lower fluidity than slurries. Active material films containing wet powders tend to be less susceptible to shape changes. Furthermore, wet powders tend to have higher lubricity (moldability) than dry powders. Therefore, the use of wet powders is expected to improve shape precision.

[0017] 4. In the method for manufacturing an electrode according to any one of the above items "1" to "3," (a) may include forming the second region by roughening the surface of the substrate sheet. The roughening may include pressing a rough-surfaced roll against the substrate sheet. The rough-surfaced roll has one or more smooth surfaces and one or more rough surfaces formed on its surface.

[0018] By using a rough-surfaced roll that includes a smooth surface and a rough surface, a substrate sheet that includes a first region (smooth surface) and a second region (rough surface) can be continuously produced.

[0019] 5. In the method for producing an electrode according to any one of the above items 1 to 4, the base sheet may have a strip-like planar shape, and the first regions and the second regions may be arranged alternately in the longitudinal direction of the base sheet.

[0020] By alternately arranging the first and second regions, non-coated portions can be formed intermittently by continuous coating (continuous application), which means that intermittent coating with high shape accuracy can be provided.

[0021] 6. The method for producing an electrode according to any one of the above items "1" to "5" may further include the following (d): (d) The current collecting member is joined to the second region by ultrasonic bonding.

[0022] The current collecting member can form a current path between the electrode and the external terminal. The current collecting member may also serve as the external terminal. By joining the current collecting member to the second region (rough surface), improved joining strength is expected.

[0023] 7. The manufacturing system manufactures an electrode by attaching an active material film to a substrate sheet. The manufacturing system includes a surface-roughening device, a conveying device, and an attaching device. The surface-roughening device is configured to roughen a portion of a base sheet. The conveying device is configured to convey the base sheet from the surface-roughening device to the attaching device. The attaching device is configured to attach the active material film to the base sheet by passing the base sheet and the active material film through a nip between rolls.

[0024] The manufacturing system described in "7" above can execute the electrode manufacturing method described in "1" above.

[0025] 8. The manufacturing system described in "7" above may further include a recovery device. The recovery device is configured to recover the remaining portion of the active material film that is not attached to the substrate sheet.

[0026] The recovered active material film may be reused, for example, as a raw material for the wet powder. By reusing the active material film, for example, improvement in material efficiency is expected.

[0027] 9. In the manufacturing system described in "7" or "8" above, the surface-texturing device may include a roughened roll. The roughened roll has one or more smooth surfaces and one or more roughened surfaces formed on its surface.

[0028] The manufacturing system described in "9" above can execute the electrode manufacturing method described in "4" above.

[0029] 10. The electrode includes a substrate sheet, an active material film, and a current collecting member. The substrate sheet includes a first region and a second region. The second region has a larger arithmetic mean roughness than the first region. The second region is adjacent to the first region. The active material film includes an active material and a binder. The active material film is disposed in the first region. The current collecting member is bonded to the second region.

[0030] The electrode described in the above item 10 can be manufactured by the electrode manufacturing method described in the above item 1. The edge of the active material film can have high shape precision.

[0031] 11. The electrode according to the above item "10" may satisfy the relationship of the following formula (1-1). Ra1<0.5D <Ra2…(1-1) In the above formula (1-1), Ra1 represents the arithmetic mean roughness of the first region, Ra2 represents the arithmetic mean roughness of the second region, and 0.5D represents 0.5 times the mean diameter of the active material.

[0032] When the relationship of the above formula (1-1) is satisfied, improvement in shape accuracy can be expected.

[0033] 12. In the electrode according to the above item "10" or "11," the first region may have an arithmetic mean roughness of, for example, 0.5 μm or less, and the second region may have an arithmetic mean roughness of, for example, 5 to 15 μm.

[0034] When the arithmetic mean roughness of the first region and the second region is within the above range, improvement in shape accuracy is expected.

[0035] 13. The electrode described in "10" to "12" above may have, for example, the following structure: In a plan view, the boundary line between the first region and the second region extends linearly. The active material film includes an edge region. The edge region extends along the boundary line. In a direction perpendicular to the boundary line, the maximum distance between the edge region and the boundary line may be 1.5 mm or less.

[0036] The maximum distance between the edge region and the boundary line in the direction perpendicular to the boundary line can be an indicator of shape precision. Hereinafter, this maximum distance will also be referred to as the "precision index." The smaller the precision index, the higher the shape precision is considered to be. For example, the electrode described in "10" above may have a precision index of 1.5 mm or less. On the other hand, an electrode manufactured by conventional intermittent coating (mask peeling) may have a precision index of 3 mm or more.

[0037] 14. The electrode according to any one of the above items "10" to "13" may have, for example, the following structure: In a cross-sectional view, the end region includes a top surface, a side surface, and a bottom surface. The bottom surface is in contact with the base sheet. The top surface is the surface opposite the bottom surface. The side surface connects the bottom surface and the top surface. The angle between the side surface and the bottom surface is 45 to 90 degrees.

[0038] The angle (acute angle) between the side and bottom surfaces can also be referred to as the inclination angle. For example, when an active material film is formed using a highly fluid paint such as a slurry, the edges of the coating film droop outward. This phenomenon can also be referred to as "dripping." When dripping occurs, the inclination angle can become smaller. For example, by using a paint with low fluidity such as a wet powder, an inclination angle of 45 degrees or more can be achieved.

[0039] 15. In the electrode according to any one of the above items "10" to "14," the active material film may satisfy, for example, the relationship of the following formula (1-2). 0.8≦α / β≦1.5 …(1-2) In the above formula (1-2), α represents the mass concentration of the specific element derived from the binder in the upper portion. β represents the mass concentration of the specific element in the lower portion. The upper portion and the lower portion are defined by dividing the active material film into two equal portions in the thickness direction. The lower portion is located between the upper portion and the substrate sheet.

[0040] For example, when an active material film is formed using a paint containing a large amount of liquid, such as a slurry, the binder migrates to the surface of the coating film together with the liquid when the paint dries. This phenomenon can also be referred to as "binder migration." Binder migration results in uneven distribution of the binder on the surface of the active material film. The uneven distribution of the binder may reduce the adhesive strength between the active material film and the substrate sheet. Furthermore, the uneven distribution of the binder may increase the battery resistance. From the viewpoint of the adhesive strength of the active material film and the battery resistance, it is desirable that the uneven distribution of the binder in the thickness direction of the active material film is small.

[0041] For example, binder migration can be reduced by using a coating material containing a small amount of liquid, such as a wet powder. "α / β" in the above formula (1-2) can also be referred to as the migration index. The closer the migration index is to 1, the smaller the bias in binder distribution in the thickness direction of the active material film is considered to be. In an active material film formed from a slurry, for example, a migration index of 2 to 3 can be observed. In an active material film formed from a wet powder, for example, a migration index of 0.8 to 1.5 can be observed.

[0042] Hereinafter, an embodiment of the present disclosure (hereinafter may be abbreviated as "the present embodiment") and an example of the present disclosure (hereinafter may be abbreviated as "the present example") will be described. However, the present embodiment and the example do not limit the technical scope of the present disclosure. The present embodiment and the example are illustrative in all respects. The present embodiment and the example are non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is originally intended that any configuration may be extracted from the present embodiment and the example and that they may be arbitrarily combined. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 is a schematic flow chart showing a method for producing an electrode in this embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing a manufacturing system according to this embodiment. [Figure 3] FIG. 3 is a schematic plan view showing a base sheet in this embodiment. [Figure 4] FIG. 4 is a schematic plan view showing an example of an electrode in this embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing an example of an electrode in this embodiment. [Figure 6] FIG. 6 is a conceptual diagram illustrating the accuracy index. [Figure 7] FIG. 7 is a conceptual diagram illustrating the migration index. [Figure 8] FIG. 8 is a conceptual diagram showing a battery according to this embodiment. [Figure 9] FIG. 9 is Table 1 showing the first battery configuration. [Figure 10] FIG. 10 is Table 2 showing the second battery configuration. [Figure 11] FIG. 11 is Table 3 showing the third battery configuration. [Figure 12] FIG. 12 is a first graph showing shape accuracy. [Figure 13] FIG. 13 is a second graph showing the shape accuracy. [Figure 14] FIG. 14 is a graph showing the battery performance. DETAILED DESCRIPTION OF THE INVENTION

[0044] <<Terms and definitions, etc.>> Some of the terms used in this specification are explained below. Terms not explained here may be defined and explained each time they are used in this specification.

[0045] The terms "comprise," "include," "have," and variations thereof (e.g., "consisting of") are open-ended. Open-ended terms may or may not include additional elements in addition to the required elements. The term "consisting of" is closed-ended. However, even closed-ended terms do not exclude additional elements that are normally incidental impurities or unrelated to the disclosed technology. The term "consisting essentially of..." is semi-closed. Semi-closed terms allow for the addition of elements that do not substantially affect the basic and novel characteristics of the disclosed technology.

[0046] Expressions such as "may" and "may" are used in the permissive sense, meaning "to have the possibility," rather than in the obligatory sense, meaning "to have to."

[0047] Unless otherwise specified, the order of execution of multiple steps, actions, operations, etc. included in various methods is not limited to the order described. For example, multiple steps may proceed simultaneously. For example, multiple steps may occur one after the other.

[0048] "At least one of A and B" includes "A or B" as well as "A and B." "At least one of A and B" can also be written as "A and / or B."

[0049] Elements expressed in the singular include the plural unless otherwise specified. For example, "particle" includes not only "one particle" but also "multiple particles (particle group)" and "aggregates of particles (powder, powder)."

[0050] Geometric terms (such as "parallel," "perpendicular," and the like) should not be interpreted in a strict sense. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms may include, for example, tolerances, errors, and the like in design, work, and manufacturing. The dimensional relationships in each drawing may not match the actual dimensional relationships. To aid the reader's understanding, the dimensional relationships (length, width, thickness, and the like) in each drawing may be changed. Furthermore, some components may be omitted.

[0051] "Plan view" refers to viewing an object from a line of sight parallel to the thickness direction of the object. "Cross-sectional view" refers to viewing an object from a line of sight perpendicular to the thickness direction of the object. "Main surface" refers to the surface with the largest area among the outer surfaces of an object (e.g., a hexahedron).

[0052] Unless otherwise specified, a numerical range such as "m to n%" includes both the upper and lower limits. That is, "m to n%" indicates a numerical range of "m% or more and n% or less." Furthermore, "m% or more and n% or less" includes "more than m% and less than n%." Furthermore, a numerical value arbitrarily selected from within the numerical range may be set as a new upper or lower limit. For example, a new numerical range may be set by arbitrarily combining a numerical value within the numerical range with a numerical value described elsewhere in this specification, in a table, a figure, or the like.

[0053] All numerical values ​​are modified by the term "about." The term "about" may mean, for example, ±5%, ±3%, ±1%, etc. All numerical values ​​may be approximate values ​​that may vary depending on the application of the disclosed technology. All numerical values ​​may be expressed with significant figures. Unless otherwise specified, measured values ​​may be average values ​​of multiple measurements. The number of measurements may be three or more, five or more, or ten or more. In general, the more measurements are made, the more reliable the average value is expected to be. Measured values ​​may be rounded to the nearest significant figure. Measured values ​​may include errors, such as those associated with the detection limits of the measuring device.

[0054] The stoichiometric composition formula indicates a representative example of a compound. The compound may have a non-stoichiometric composition. For example, "Al2O3" is not limited to a compound having a molar ratio of "Al / O=2 / 3." Unless otherwise specified, "Al2O3" indicates a compound containing Al and O in any molar ratio. Furthermore, for example, the compound may be doped with a trace element, or a portion of Al and O may be substituted with another element.

[0055] The term "derivative" refers to a compound in which a part of a parent compound has been modified by at least one method selected from the group consisting of introduction of a substituent, substitution of an atom, oxidation, reduction, and other chemical reactions. The modification may be at one or more locations. The "substituent" may include at least one selected from the group consisting of, for example, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, unsaturated cycloalkyl groups, aromatic groups, heterocyclic groups, halogen atoms (such as F, Cl, Br, and I), OH groups, SH groups, CN groups, SCN groups, OCN groups, nitro groups, alkoxy groups, unsaturated alkoxy groups, amino groups, alkylamino groups, dialkylamino groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, acyloxy groups, aryloxycarbonyl groups, acylamino groups, alkoxycarbonylamino groups, aryloxycarbonylamino groups, sulfonylamino groups, sulfamoyl groups, carbamoyl groups, alkylthio groups, arylthio groups, sulfonyl groups, sulfinyl groups, ureido groups, phosphoric acid amide groups, sulfo groups, carboxy groups, hydroxamic acid groups, sulfino groups, hydrazino groups, imino groups, and silyl groups. These substituents may be further substituted. When there are two or more substituents, the substituents may be the same or different. Multiple substituents may be bonded to each other to form a ring. Derivatives of polymer compounds (resin materials) may also be called "modified products."

[0056] The "copolymer" includes at least one selected from the group consisting of unspecified type, statistical type, random type, alternating type, periodic type, block type, and graft type.

[0057] "Arithmetic mean roughness" refers to the "arithmetic mean roughness Ra" described in "JIS B 0601." The arithmetic mean roughness can be measured using a non-contact surface roughness meter. The arithmetic mean roughness has a unit of [μm].

[0058] "D50" refers to the particle size at which the cumulative frequency from the smallest particle size reaches 50% in a volumetric particle size distribution. The D50 of an active material or the like can be measured by a laser diffraction method. The D50 of a wet powder can be measured by a sieving test described in "JIS Z 8815."

[0059] "Solid content" refers to the total mass fraction of all components in a paint (e.g., wet powder) other than the liquid. Note that the binder dissolved in the liquid is considered a component other than the liquid.

[0060] "Electrode" is a general term for positive electrodes and negative electrodes. Thus, for example, "electrode active material" is a general term for positive electrode active material and negative electrode active material. For example, "electrode active material layer" is a general term for positive electrode active material layer and negative electrode active material layer. The electrode may refer to at least one of the positive electrode and the negative electrode. The electrode may also refer to a bipolar electrode.

[0061] "Weight" indicates the mass of the coating film (electrode active material layer) per unit area.

[0062] "Average diameter" refers to the average value of the Feret diameter of the active material (particle group) in the cross section of the active material film. The "Feret diameter" is measured by microscopy. The Feret diameter is the distance between the two most distant points on the outline of the particle. The arithmetic mean of the Feret diameters of 100 or more particles is considered to be the average diameter.

[0063] The "migration index" is measured using the following procedure: A sample is cut from an electrode. The cut surface of the sample is parallel to the thickness direction of the active material film. The cut surface of the active material film is cross-sectionally processed. For example, cross-sectional processing may be performed using an ion milling device. The sample is analyzed using an EPMA (Electron Probe Micro Analyzer). FIG. 7 is a conceptual diagram illustrating the migration index. In the sample, the active material film 120 is divided into two equal parts in the thickness direction, dividing the active material film into an upper part 120a and a lower part 120b. The lower part 120b is located between the upper part 120a and the base sheet 110. A specific element is selected depending on the type of binder. The specific element is an element that can serve as a binder marker. For example, if the binder contains polyvinylidene fluoride (PVdF), F may be used as the specific element. If the binder does not contain an appropriate element, the sample may be subjected to a known dyeing process to impart the specific element to the binder. For example, when the binder contains styrene butadiene rubber (SBR), the sample may be stained with Os or the like. For example, when the binder contains carboxymethyl cellulose (CMC), the sample may be stained with Ru or the like. By concentration mapping analysis using EPMA, the mass concentration (α) of a specific element in the upper portion 120a and the mass concentration (β) of a specific element in the lower portion 120b are measured. The migration index (α / β) is calculated by dividing α by β.

[0064] "Battery" includes any battery system. Batteries may include, for example, lithium ion batteries, sodium ion batteries, nickel-metal hydride batteries, etc. Batteries may be used for any purpose. Applications of batteries may include, for example, electric vehicles, power tools, mobile devices, stationary power sources, etc.

[0065] <<Electrode manufacturing method>> FIG. 1 is a schematic flowchart showing a method for manufacturing an electrode according to this embodiment. Hereinafter, the "method for manufacturing an electrode according to this embodiment" may be abbreviated as "the present manufacturing method." The present manufacturing method includes "(a) preparation of a substrate sheet," "(b) preparation of an active material film," and "(c) attachment." The order shown in FIG. 1 is merely an example. For example, "(b) preparation of an active material film" may be performed before "(a) preparation of a substrate sheet." "(a) preparation of a substrate sheet" and "(b) preparation of an active material film" may be performed simultaneously. The present manufacturing method may further include, for example, "(d) ultrasonic bonding," etc. The present manufacturing method may further include, for example, drying, compressing, cutting, etc.

[0066] <Manufacturing System> 2 is a conceptual diagram showing a manufacturing system according to this embodiment. The manufacturing system 20 can manufacture the electrode 100 (raw sheet) by a roll-to-roll method. For example, the manufacturing system 20 can execute the present manufacturing method (see FIG. 1).

[0067] The manufacturing system 20 includes a roughening device 21, a conveying device 22, and an attaching device 23. The manufacturing system 20 may further include, for example, a recovery device 24. The manufacturing system 20 may further include, for example, a control device, a drying device, a compression device, a cutting device, etc. In the manufacturing system 20, the individual devices may be separate and independent from each other. Alternatively, multiple devices may be integrated to form a single device. The curved arrows in FIG. 2 indicate the rotation direction of each roll member.

[0068] <(a) Preparation of base sheet> This manufacturing method includes preparing a base sheet 110. The base sheet 110 includes a first main surface 110a and a second main surface 110b (see FIG. 2). The second main surface 110b is the surface opposite to the first main surface 110a. The base sheet 110 can have any thickness. For example, the base sheet 110 may have a thickness of 5 to 100 μm. The thickness of the base sheet 110 may be, for example, 5 to 20 μm, 20 to 50 μm, or 50 to 100 μm.

[0069] The substrate sheet 110 may be conductive. In the battery, the substrate sheet 110 may function as a current collector. The substrate sheet 110 may contain, for example, a metal, a resin, etc. The substrate sheet 110 may contain, for example, a metal foil, a conductive resin sheet, etc. The metal foil may contain, for example, at least one selected from the group consisting of Al, Mn, Cu, Ni, Ti, Fe, and Cr. The metal foil may contain, for example, at least one selected from the group consisting of Al foil, Al alloy foil, Ni foil, Ni alloy foil, Cu foil, Cu alloy foil, Ti foil, Ti alloy foil, and stainless steel foil. The conductive resin sheet may contain, for example, a matrix resin and a conductive filler, etc. The matrix resin may contain, for example, polyethylene (PE), etc. The conductive filler may contain, for example, metal powder, carbon powder, etc. The substrate sheet 110 may have a single-layer structure or a multi-layer structure. For example, two or more metal foils may be laminated to form the base sheet 110. For example, an Al foil and a Cu foil may be bonded together to prepare the base sheet 110 (current collector) for a bipolar battery.

[0070] 3 is a schematic plan view showing a base sheet in this embodiment. At least one of the first main surface 110a and the second main surface 110b includes a first region 111 and a second region 112. A coating portion may be formed in the first region 111. The second region 112 is a region that is to become a non-coating portion. The second region 112 is adjacent to the first region 111. For example, the second region 112 may surround the first region 111.

[0071] The base sheet 110 may have a strip-like (long rectangular) planar shape. The base sheet 110 may include a plurality of first regions 111 and a plurality of second regions 112. The first regions 111 and the second regions 112 may be arranged alternately in the length direction (Y-axis direction) of the base sheet 110. The second regions 112 may be arranged periodically or non-periodically.

[0072] A pair of adjacent first and second regions 111 and 112 may correspond to one electrode (piece). A boundary line 113 is formed between the first and second regions 111 and 112. The boundary line 113 extends in the width direction (X-axis direction). The width direction is perpendicular to the length direction. The boundary line 113 may extend linearly. The base sheet 110 may be transported in the length direction. The length direction of the base sheet 110 may be parallel to the direction in which the workpiece is transported.

[0073] The first region 111 has a smooth surface. The second region 112 has a rough surface. The second region 112 has a larger arithmetic mean roughness than the first region 111. For example, the arithmetic mean roughness of each region and the D50 of the active material may satisfy the relationship of the following formula (1-3).

[0074] Ra1<0.5D50 <Ra2…(1-3) In the formula, Ra1 represents the arithmetic mean roughness of the first region 111. Ra2 represents the arithmetic mean roughness of the second region 112. 0.5D50 represents 0.5 times the D50 of the active material.

[0075] The roughness ratio (Ra2 / Ra1) may be, for example, 2 or more, 5 or more, 10 or more, 50 or more, 100 or more, or 200 or more. The roughness ratio (Ra2 / Ra1) may be, for example, 1000 or less, 500 or less, or 300 or less.

[0076] Ra1 may be, for example, 0.5 μm or less, 0.3 μm or less, 0.2 μm or less, 0.1 μm or less, or 0.05 μm or less.

[0077] Ra2 may be, for example, 5 μm or more, 7.5 μm or more, or 10 μm or more.Ra2 may be, for example, 20 μm or less, 15 μm or less, or 12.5 μm or less.

[0078] The D50 of the active material may be, for example, 1 to 30 μm, 5 to 20 μm, 10 to 20 μm, or 5 to 10 μm.

[0079] The second region 112 (rough surface) can be formed by any method, for example, by imparting roughness to a portion of the base sheet 110 by at least one method selected from the group consisting of surface roughening, laser processing, blasting, and chemical etching.

[0080] For example, the second region 112 may be formed by roughening (roll embossing, knurling, etc.). The use of roll processing is expected to improve productivity, for example. For example, the roughening may be performed by a roughening device 21 (see FIG. 2). The roughening device 21 may include, for example, a first rough-surface roll 21a. The surface of the first rough-surface roll 21a has one or more smooth surfaces 1 and one or more rough surfaces 2. The rough surface 2 includes irregularities (engravings). For example, the irregularities may be formed by laser engraving. The irregularity pattern may be regular or random.

[0081] The rotating first rough-surface roll 21a is continuously pressed against the base sheet 110 (first main surface 110a), thereby forming a rough surface intermittently on the first main surface 110a. That is, first regions 111 (smooth surfaces) and second regions 112 (rough surfaces) can be formed alternately in the longitudinal direction of the base sheet 110.

[0082] The surface-roughening device 21 may further include a second rough-surface roll 21b. The second rough-surface roll 21b may have, for example, the same structure as the first rough-surface roll 21a. For example, a third roll nip G3 may be formed between the first rough-surface roll 21a and the second rough-surface roll 21b. By passing the base sheet 110 through the third roll nip G3, a rough surface can be formed on both the first main surface 110a and the second main surface 110b.

[0083] <(b) Preparation of the active material film> The manufacturing method includes preparing an active material film 120. The active material film 120 is a film containing an active material. The active material film 120 can be formed by any method. For example, the active material film 120 may be formed by applying a slurry, a dry powder, or the like. For example, the manufacturing method may include "(b1) preparing a wet powder" and "(b2) forming a film," etc.

[0084] (b1) Preparation of wet powder The manufacturing method may include, for example, preparing a wet powder 10 containing an active material and a binder. The wet powder 10 may be prepared, for example, by wet granulation. That is, for example, the active material, the binder, and a liquid may be mixed in an agitation granulation device to form the wet powder 10. The wet powder may be, for example, clay-like, powder-like, granular, or the like. The wet powder 10 may have a D50 of, for example, 0.01 to 0.1 mm, 0.1 to 1 mm, or 1 to 3 mm.

[0085] The solid content is adjusted so that the wet powder 10 is formed. The solid content may be 80% or more, 85% or more, or 90% or more. The solid content may be, for example, less than 100%, 99% or less, 95% or less, or 90% or less. The slurry may have a solid content of, for example, less than 70%. The range of solid content at which the wet powder 10 can be formed may vary depending on, for example, the powder properties of the active material.

[0086] The active material causes an electrode reaction in the battery. The active material is in the form of powder. The active material may be a positive electrode active material or a negative electrode active material. The binder can adhere the active material film 120 to the base sheet 110.

[0087] The liquid can promote granulation by forming liquid bridges between particles. The liquid can be selected, for example, depending on the type of binder. The liquid may contain, for example, an aqueous solvent, an organic solvent, etc. The aqueous solvent contains water. The aqueous solvent may further contain, in addition to water, a polar organic solvent that is miscible with water. The aqueous solvent may further contain, in addition to water, for example, an alcohol, a ketone, etc. The liquid may contain, for example, at least one selected from the group consisting of N-methylpyrrolidone (NMP), water, tetralin, and butyl butyrate.

[0088] Components other than the active material, binder, and liquid may be added to the wet powder. For example, a conductive material, a solid electrolyte, etc. The chemical composition of the solid components will be explained in the "positive electrode" and "negative electrode" sections below.

[0089] 《(b2) Film formation》 The manufacturing method may include, for example, forming the wet powder 10 into an active material film 120. For example, the active material film 120 may be formed by roll forming. That is, the active material film 120 may be formed by passing the wet powder 10 through a nip between rolls.

[0090] For example, the laminating device 23 may also function as a film forming device. By having the laminating device 23 also function as a film forming device, the manufacturing system 20 can be made more compact. The laminating device 23 may include, for example, a first roll 23a, a second roll 23b, and a third roll 23c. The second roll 23b rotates in the opposite direction to the first roll 23a. The third roll 23c rotates in the opposite direction to the second roll 23b. A first roll nip G1 is formed between the first roll 23a and the second roll 23b. A second roll nip G2 is formed between the second roll 23b and the third roll 23c. For example, the rotational speeds of the rolls may satisfy the relationship of the following formula (1-4).

[0091] ω1<ω2<ω3 …(1-4) In the formula, ω1 represents the rotation speed of the first roll 23a, ω2 represents the rotation speed of the second roll 23b, and ω3 represents the rotation speed of the third roll 23c.

[0092] The workpiece (wet powder 10, active material film 120) may be carried away by the roll of the pair that rotates faster. This is thought to be because the faster the rotation speed, the larger the contact area between the roll and the workpiece in a short period of time, which increases the adhesive force.

[0093] The wet powder 10 is supplied to the first roll nip G1. In the first roll nip G1, the wet powder 10 is compressed to form an active material film 120. For example, the thickness of the active material film 120 can be adjusted by the size of the first roll nip G1. In the first roll nip G1, the width of the active material film 120 may be adjusted by, for example, scrapers (not shown) or partition plates (not shown) arranged at both ends in the width direction.

[0094] The active material film 120 can be carried away by the second roll 23b. The first roll 23a may have an arithmetic mean roughness of, for example, 0 to 10 μm. The second roll 23b may have an arithmetic mean roughness of, for example, 0 to 10 μm.

[0095] <(c)Paste> This manufacturing method includes attaching the active material film 120 to the base sheet 110 by passing the base sheet 110 and the active material film 120 through a nip between rolls. The active material film 120 is attached to both the first region 111 and the second region 112, straddling the boundary line 113 between the first region 111 and the second region 112. The active material film 120 may be attached to the base sheet 110 continuously, for example.

[0096] In this manufacturing method, the active material film 120 is selectively attached to the first region 111 out of the first region 111 and the second region 112. For example, when the active material film 120 is attached to the first region 111 and the second region 112 under the same conditions, if the basis weight (first basis weight) of the active material film 120 attached to the first region 111 is larger than the basis weight (second basis weight) of the active material film 120 attached to the second region 112, the active material film 120 is considered to be selectively attached to the first region 111. The ratio of the second basis weight to the first basis weight may be, for example, 0.1 or less, 0.01 or less, 0.001 or less, or 0.0001 or less. The second basis weight may be substantially zero.

[0097] For example, the attachment device 23 may attach the active material film 120 to the base sheet 110 (see FIG. 2). The second roll 23b may supply the active material film 120 to the second roll nip G2. The conveying device 22 may supply the base sheet 110 to the second roll nip G2. That is, the conveying device 22 may convey the base sheet 110 from the surface roughening device 21 to the attachment device 23. The conveying device 22 may include, for example, a roll feeder or the like.

[0098] In the second roll nip G2, the active material film 120 is attached to the base sheet 110. The active material film 120 can be selectively attached to the first region 111. The active material film 120 cannot substantially be attached to the second region 112. Thus, the active material film 120 can be arranged intermittently on the base sheet 110.

[0099] The portion of the active material film 120 corresponding to the second region 112 can be discharged from the second roll nip G2 while remaining on the second roll 23b. This manufacturing method may, for example, include recovering the remainder of the active material film 120 that is not attached to the base sheet 110. For example, the recovery device 24 may recover the remainder. The recovery device 24 may, for example, include a scraper 24a and a suction device 24b. The scraper 24a can peel the active material film 120 from the second roll 23b. The peeled active material film 120 (remnant) can be recovered by the suction device 24b. The recovered remainder may be reused. For example, the remainder after pulverization may be mixed with the wet powder 10. Reusing the remainder is expected to improve material efficiency.

[0100] The electrode 100 (raw sheet) can be manufactured by intermittently arranging the active material film 120 on the first main surface 110a. Similarly to the first main surface 110a, the active material film 120 may also be attached to the second main surface 110b. The dimensions of the first region 111 (smooth surface) may be the same or different between the first main surface 110a and the second main surface 110b. The dimensions of the second region 112 (rough surface) may be the same or different between the first main surface 110a and the second main surface 110b. The dimensions of the active material film 120 may be the same or different between the first main surface 110a and the second main surface 110b. The polarity of the active material film 120 may be the same or different between the first main surface 110a and the second main surface 110b. That is, the electrode 100 may be a bipolar electrode.

[0101] <Other operations> The present manufacturing method may include drying the electrode 100. For example, the active material film 120 may be dried using a hot air dryer, an infrared dryer, or the like. The active material film 120 may also be air-dried.

[0102] The manufacturing method may include compressing the electrode 100. For example, the electrode 100 may be compressed after drying. For example, the electrode 100 may be compressed using a rolling mill.

[0103] This manufacturing method may include cutting the electrode 100 (raw sheet). The raw sheet may be cut to a predetermined size depending on the battery design. For example, the electrode 100 may be cut in the first region 111 (coated portion), or the electrode 100 may be cut in the second region 112 (non-coated portion). The cutting line may be parallel to the width direction of the electrode 100 or parallel to the length direction of the electrode 100, for example.

[0104] <(d) Ultrasonic bonding> This manufacturing method may include joining the current collecting member 130 to the second region 112 (rough surface) by ultrasonic bonding. The current collecting member 130 may include, for example, a current collecting plate, a current collecting tab, a current collecting lead, etc. The current collecting member 130 may include, for example, Al, Ni, Cu, etc. By joining the current collecting member 130 to the second region 112, it is expected that the bonding strength will be improved.

[0105] <<Electrode>> Fig. 4 is a schematic plan view showing an example of an electrode in this embodiment. Fig. 5 is a schematic cross-sectional view showing an example of an electrode in this embodiment. The electrode 100 can have any planar shape. In plan view, the electrode 100 may be, for example, sheet-shaped (rectangular) or strip-shaped.

[0106] The electrode 100 includes a substrate sheet 110, an active material film 120, and a current collecting member 130 (see FIG. 4). Each element may have any planar shape. In plan view, the active material film 120 and the substrate sheet 110 may each be, for example, rectangular (see FIG. 4).

[0107] The substrate sheet 110 is a current collector. The substrate sheet 110 includes a first main surface 110a and a second main surface 110b (see FIG. 5). The active material film 120 is disposed on the first main surface 110a (one side). The active material film 120 may be disposed on both the first main surface 110a and the second main surface 110b.

[0108] The base sheet 110 includes a first region 111 and a second region 112. An active material film 120 is disposed in the first region 111. The active material film 120 may cover the entire first region 111. The active material film 120 may cover a portion of the first region 111. The second region 112 is a non-coated portion. The base sheet 110 is exposed in the second region 112. A current collecting member 130 is bonded to the second region 112. Non-coated portions may or may not be provided at both ends in the width direction (X-axis direction).

[0109] <Arithmetic mean roughness> The electrode 100 may, for example, satisfy the relationship of the following formula (1-1). Ra1<0.5D <Ra2…(1-1) In the above formula (1-1), Ra1 represents the arithmetic mean roughness of the first region 111. Ra2 represents the arithmetic mean roughness of the second region 112. 0.5D represents 0.5 times the average diameter of the active material. When the relationship of the above formula (1-1) is satisfied, improvement in shape precision is expected.

[0110] Ra1 may be, for example, 0.5 μm or less, 0.3 μm or less, 0.2 μm or less, 0.1 μm or less, or 0.05 μm or less.

[0111] Ra2 may be, for example, 5 to 15 μm. Ra2 may be, for example, 7.5 μm or more, or 10 μm or more. Ra2 may be, for example, 20 μm or less, 15 μm or less, or 12.5 μm or less.

[0112] The average diameter of the active material may be, for example, 1 to 30 μm, 5 to 20 μm, 10 to 20 μm, or 5 to 10 μm. The average diameter of the active material may be a value similar to the D50 of the active material.

[0113] <Shape accuracy> FIG. 6 is a conceptual diagram illustrating the precision index. Region VI in FIG. 6 corresponds to region VI in FIG. 4. In a plan view, the boundary line 113 between the first region 111 and the second region 112 extends linearly. The active material film 120 includes an end region 120e. The end region 120e extends along the boundary line 113. The end region 120e may have undulations in a direction perpendicular to the boundary line 113 (the Y-axis direction). The maximum distance between the end region 120e and the boundary line 113 in the Y-axis direction (the distance between the apex of the undulation and the boundary line 113) is the precision index. The smaller the precision index, the higher the shape precision. The precision index may be, for example, 1.5 mm or less. The precision index may be, for example, 1.2 mm or less, 1.0 mm or less, 0.8 mm or less, 0.6 mm or less, or 0.4 mm or less.

[0114] Generally, the greater the width (dimension in the X-axis direction) of the active material film 120, the lower the shape accuracy tends to be. In this embodiment, high shape accuracy can be maintained even if the width of the active material film 120 increases. For example, the accuracy index may be 1.5 mm or less over a range of 100 mm or more, 200 mm or more, 500 mm or more, or 1000 mm or more.

[0115] <Tilt angle> In a cross-sectional view, the end region 120e includes an upper surface 121, a side surface 122, and a bottom surface 123 (see FIG. 5). The bottom surface 123 is in contact with the base sheet 110. The upper surface 121 is the surface opposite the bottom surface 123. The upper surface 121 may be parallel to the bottom surface 123. The side surface 122 connects the bottom surface 123 and the upper surface 121. The angle (acute angle) formed between the side surface 122 and the bottom surface 123 is the inclination angle (θ). The closer the inclination angle is to 90 degrees, the higher the shape accuracy is considered to be. Furthermore, the closer the inclination angle is to 90 degrees, the more improved the energy density, for example. The inclination angle may be, for example, 45 to 90 degrees. The inclination angle may be, for example, 45 to 60 degrees, 60 to 75 degrees, or 75 to 90 degrees.

[0116] <Migration Index> In this embodiment, it is expected that there will be little bias in the distribution of the binder in the thickness direction of the active material film 120. That is, the active material film 120 may satisfy, for example, the relationship of the following formula (1-2).

[0117] 0.8≦α / β≦1.5 …(1-2) In the formula, α represents the mass concentration of the specific element derived from the binder in the upper portion 120a (see FIG. 7). β represents the mass concentration of the specific element in the lower portion 120b. The upper portion 120a and the lower portion 120b are defined by dividing the active material film 120 into two equal portions in the thickness direction. The lower portion 120b is located between the upper portion 120a and the base sheet 110.

[0118] The above formula (1-2) indicates that the migration index is 0.8 to 1.5. The migration index may be, for example, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, or 1.05 or less. The migration index may be, for example, 0.9 or more, 0.95 or more, or 1 or more.

[0119] <<Battery>> Fig. 8 is a conceptual diagram showing a battery in this embodiment. The battery 1000 may be, for example, a liquid battery, a polymer battery, or an all-solid-state battery. The battery 1000 may be, for example, a monopolar battery (unipolar battery) or a bipolar battery. Fig. 8 shows a monopolar battery as an example.

[0120] <Exterior body> The battery 1000 may include an exterior body (not shown). The exterior body may house the power generating element 500. The exterior body may have any shape. For example, the exterior body may be a metal case or a pouch made of a metal foil laminated film. The exterior body may be, for example, cylindrical, rectangular, button-shaped, flat, or the like. The exterior body may contain, for example, Al, or the like.

[0121] <Power generation elements> The battery 1000 includes a power generating element 500. The power generating element 500 may also be referred to as, for example, an "electrode group" or an "electrode body." The power generating element 500 includes a first electrode 101, a separator 200, a second electrode 102, and an electrolyte (not shown). For example, each element may be impregnated with a liquid electrolyte. For example, each element may include a solid electrolyte.

[0122] The power generating element 500 may be, for example, a laminated type. For example, the power generating element 500 may be formed by alternately laminating the first electrodes 101 and the second electrodes 102 with the separator 200 sandwiched between them. The power generating element 500 may be, for example, a wound type. For example, a strip-shaped first electrode 101, a strip-shaped separator 200, and a strip-shaped second electrode 102 may be laminated to form a laminate. The laminate may be spirally wound to form the power generating element 500. The wound type power generating element 500 may be formed into a flat shape after winding.

[0123] The second electrode 102 has an opposite polarity to the first electrode 101. When the first electrode 101 is a positive electrode, the second electrode 102 is a negative electrode. When the first electrode 101 is a negative electrode, the second electrode 102 is a positive electrode. At least one of the first electrode 101 and the second electrode 102 is the aforementioned electrode 100. The separator 200 is interposed between the first electrode 101 and the second electrode 102. The separator 200 separates the first electrode 101 from the second electrode 102.

[0124] <Positive electrode> The positive electrode includes a substrate sheet 110 and an active material film 120. The active material film 120 in the positive electrode may also be referred to as a "positive electrode active material layer," for example. The positive electrode active material layer may have a thickness of, for example, 10 to 1000 μm, 50 to 500 μm, or 100 to 300 μm. The positive electrode active material layer may have a thickness of, for example, 5 to 100 mg / cm 2 , 10-50mg / cm 2 , or 20-40 mg / cm 2 The positive electrode active material layer may have a weight per unit area of, for example, 2 to 5 g / cm. 3 , 2.5~4g / cm3 , or 3 to 3.5 g / cm 3 The density of the electrode active material layer may be referred to as the "composite density." The positive electrode active material layer includes a positive electrode active material. The positive electrode active material layer may further include, for example, a conductive material, a binder, and the like.

[0125] Conductive materials The conductive material can form an electron conduction path within the positive electrode active material layer. The amount of the conductive material may be, for example, 0.1 to 10 parts by mass relative to 100 parts by mass of the positive electrode active material. The conductive material can contain any component. For example, the conductive material may contain at least one material selected from the group consisting of graphite, acetylene black (AB), Ketjen Black (registered trademark), vapor-grown carbon fiber (VGCF), carbon nanotubes (CNT), and graphene flakes (GF).

[0126] Binder The binder can bond the positive electrode active material layer to the current collector (substrate sheet 110). The amount of binder may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the positive electrode active material. The binder may contain any component. For example, the binder may contain at least one selected from the group consisting of PVdF, vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), polytetrafluoroethylene (PTFE), CMC, polyacrylic acid (PAA), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyoxyethylene alkyl ether, and derivatives thereof.

[0127] Other ingredients The positive electrode active material layer may further contain, for example, an inorganic filler, an organic filler, a solid electrolyte, a surface modifier, a dispersant, a lubricant, a flame retardant, a protective agent, a flux, a coupling agent, an adsorbent, etc. The positive electrode active material layer may also contain, for example, polyoxyethylene allyl phenyl ether phosphate, zeolite, a silane coupling agent, MoS2, WO3, etc.

[0128] 《Cathode active material》 The positive electrode active material undergoes a positive electrode reaction. The positive electrode active material may have a D50 of, for example, 1 to 30 μm, 10 to 20 μm, or 1 to 10 μm. The positive electrode active material may contain any components. The positive electrode active material may contain, for example, transition metal oxides, polyanion compounds, etc. Within one particle (positive electrode active material), the composition may be uniform or non-uniform. For example, the composition may vary from the surface to the center of the particle. The composition may change continuously or discontinuously (stepwise).

[0129] 〈Transition metal oxide: Space group R-3m〉 The transition metal oxide may have any crystal structure. The transition metal oxide may contain, for example, a crystal structure belonging to the space group R-3m. For example, a compound represented by the general formula "LiMO2" may have a crystal structure belonging to the space group R-3m. The transition metal oxide may be represented, for example, by the following formula (2-1).

[0130] Li 1-a Ni x M 1-x O2…(2-1) In the formula, the relationship of -0.5 ≦ a ≦ 0.5 and 0 ≦ x ≦ 1 is satisfied. M may contain, for example, at least one selected from the group consisting of Co, Mn, and Al.

[0131] In the above formula (2-1), x may satisfy, for example, the relationship of 0 < x ≦ 0.1, 0.1 ≦ x ≦ 0.2, 0.2 ≦ x ≦ 0.3, 0.3 ≦ x ≦ 0.4, 0.4 ≦ x ≦ 0.5, 0.5 ≦ x ≦ 0.6, 0.6 ≦ x ≦ 0.7, 0.7 ≦ x ≦ 0.8, 0.8 ≦ x ≦ 0.9, or 0.9 ≦ x ≦ 1. a may satisfy, for example, the relationship of -0.4 ≦ a ≦ 0.4, -0.3 ≦ a ≦ 0.3, -0.2 ≦ a ≦ 0.2, or -0.1 ≦ a ≦ 0.1.

[0132] The transition metal oxide is, for example, LiCoO2, LiMnO2, LiNi 0.9 Co 0.1 O2, LiNi0.9 Mn 0.1 It may contain at least one selected from the group consisting of O2 and LiNiO2.

[0133] 〈NCM〉 The transition metal oxide may be represented, for example, by the following formula (2-2). The compound represented by the following formula (2-2) may also be referred to as "NCM".

[0134] Li 1-a Ni x Co y Mn z O2…(2-2) In the formula, the relationship of -0.5 ≦ a ≦ 0.5, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1 is satisfied.

[0135] In the above formula (2-2), x may satisfy, for example, the relationship of 0 < x ≦ 0.1, 0.1 ≦ x ≦ 0.2, 0.2 ≦ x ≦ 0.3, 0.3 ≦ x ≦ 0.4, 0.4 ≦ x ≦ 0.5, 0.5 ≦ x ≦ 0.6, 0.6 ≦ x ≦ 0.7, 0.7 ≦ x ≦ 0.8, 0.8 ≦ x ≦ 0.9, or 0.9 ≦ x < 1.

[0136] In the above formula (2-2), y may satisfy, for example, the relationship of 0 < y ≦ 0.1, 0.1 ≦ y ≦ 0.2, 0.2 ≦ y ≦ 0.3, 0.3 ≦ y ≦ 0.4, 0.4 ≦ y ≦ 0.5, 0.5 ≦ y ≦ 0.6, 0.6 ≦ y ≦ 0.7, 0.7 ≦ y ≦ 0.8, 0.8 ≦ y ≦ 0.9, or 0.9 ≦ y < 1.

[0137] In the above formula (2-2), z may satisfy, for example, the relationship of 0 < z ≦ 0.1, 0.1 ≦ z ≦ 0.2, 0.2 ≦ z ≦ 0.3, 0.3 ≦ z ≦ 0.4, 0.4 ≦ z ≦ 0.5, 0.5 ≦ z ≦ 0.6, 0.6 ≦ z ≦ 0.7, 0.7 ≦ z ≦ 0.8, 0.8 ≦ z ≦ 0.9, or 0.9 ≦ z < 1.

[0138] NCM is, for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.4 Co 0.3 Mn0.3 O2, LiNi 0.3 Co 0.4 Mn 0.3 O2, LiNi 0.3 Co 0.3 Mn 0.4 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.5 Co 0.3 Mn 0.2 O2, LiNi 0.5 Co 0.4 Mn 0.1 O2, LiNi 0.5 Co 0.1 Mn 0.4 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.6 Co 0.3 Mn 0.1 O2, LiNi 0.6 Co 0.1 Mn 0.3 O2, LiNi 0.7 Co 0.1 Mn 0.2 O2, LiNi 0.7 Co 0.2 Mn 0.1 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, and LiNi 0.9 Co 0.05 Mn 0.05 It may contain at least one selected from the group consisting of O2.

[0139] 〈NCA〉 The transition metal oxide may be represented, for example, by the following formula (2-3). The compound represented by the following formula (2-3) may also be referred to as "NCA".

[0140] Li 1-a Ni x Co y Al z O2…(2-3) In the formula, the relationships of -0.5 ≦ a ≦ 0.5, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1 are satisfied.

[0141] In the above formula (2-3), x may satisfy a relationship such as 0 < x ≤ 0.1, 0.1 ≤ x ≤ 0.2, 0.2 ≤ x ≤ 0.3, 0.3 ≤ x ≤ 0.4, 0.4 ≤ x ≤ 0.5, 0.5 ≤ x ≤ 0.6, 0.6 ≤ x ≤ 0.7, 0.7 ≤ x ≤ 0.8, 0.8 ≤ x ≤ 0.9, or 0.9 ≤ x < 1.

[0142] In the above formula (2-3), y may satisfy a relationship such as 0 < y ≤ 0.1, 0.1 ≤ y ≤ 0.2, 0.2 ≤ y ≤ 0.3, 0.3 ≤ y ≤ 0.4, 0.4 ≤ y ≤ 0.5, 0.5 ≤ y ≤ 0.6, 0.6 ≤ y ≤ 0.7, 0.7 ≤ y ≤ 0.8, 0.8 ≤ y ≤ 0.9, or 0.9 ≤ y < 1.

[0143] In the above formula (2-3), z may satisfy a relationship such as 0 < z ≤ 0.1, 0.1 ≤ z ≤ 0.2, 0.2 ≤ z ≤ 0.3, 0.3 ≤ z ≤ 0.4, 0.4 ≤ z ≤ 0.5, 0.5 ≤ z ≤ 0.6, 0.6 ≤ z ≤ 0.7, 0.7 ≤ z ≤​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The positive electrode active material may contain, for example, two or more types of NCM. The positive electrode active material may contain, for example, NCM(0.6≦x) and NCM(x<0.6). "NCM(0.6≦x)" refers to a compound in which x (Ni ratio) in the above formula (2-2) is 0.6 or more. NCM(0.6≦x) may also be referred to as, for example, a "high nickel material." NCM(0.6≦x) is, for example, LiNi 0.8 Co 0.1 Mn 0.1 O2, etc. "NCM (x<0.6)" refers to a compound in which x (Ni ratio) is less than 0.6 in the above formula (2-2). NCM (x<0.6) is, for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc. The mixing ratio (mass ratio) of NCM(0.6≦x) and NCM(x<0.6) may be, for example, "NCM(0.6≦x) / NCM(x<0.6)=9 / 1 to 1 / 9," "NCM(0.6≦x) / NCM(x<0.6)=9 / 1 to 4 / 6," or "NCM(0.6≦x) / NCM(x<0.6)=9 / 1 to 3 / 7."

[0146] The positive electrode active material may contain, for example, NCA and NCM. The mixing ratio (mass ratio) of NCA and NCM may be, for example, "NCA / NCM = 9 / 1 to 1 / 9," "NCA / NCM = 9 / 1 to 4 / 6," or "NCA / NCM = 9 / 1 to 3 / 7." The Ni ratios of NCA and NCM may be the same or different. The Ni ratio of NCA may be higher than the Ni ratio of NCM. The Ni ratio of NCA may be lower than the Ni ratio of NCM.

[0147] <Transition metal oxides: space group C2 / m> The transition metal oxide may have, for example, a crystal structure belonging to the space group C2 / m. The transition metal oxide may be represented by, for example, the following formula (2-4).

[0148] Li2MO3…(2-4) In the formula, M may include, for example, at least one selected from the group consisting of Ni, Co, Mn, and Fe.

[0149] The positive electrode active material may include, for example, a mixture of LiMO2 (space group R-3m) and Li2MO3 (space group C2 / m), or a solid solution of LiMO2 and Li2MO3 (Li2MO3-LiMO2).

[0150] <Transition metal oxides: space group Fd-3m> The transition metal oxide may have, for example, a crystal structure belonging to the space group Fd-3m. The transition metal oxide may be represented by, for example, the following formula (2-5).

[0151] LiMn 2-x M x O4…(2-5) In the formula, the relationship 0≦x≦2 is satisfied. M may include, for example, at least one selected from the group consisting of Ni, Fe, and Zn.

[0152] LiM2O4 (space group Fd-3m) is, for example, LiMn2O4 and LiMn 1.5 Ni 0.5 The positive electrode active material may contain at least one selected from the group consisting of LiMO2 (space group R-3m) and LiM2O4 (space group Fd-3m). The positive electrode active material may contain, for example, a mixture of LiMO2 (space group R-3m) and LiM2O4 (space group Fd-3m). The mixing ratio (mass ratio) of LiMO2 (space group R-3m) and LiM2O4 (space group Fd-3m) may be, for example, "LiMO2 / LiM2O4 = 9 / 1 to 9 / 1," "LiMO2 / LiM2O4 = 9 / 1 to 5 / 5," or "LiMO2 / LiM2O4 = 9 / 1 to 7 / 3."

[0153] <Polyanion Compounds> The polyanion compound may include, for example, a phosphate (such as LiFePO4), a silicate, a borate, etc. The polyanion compound may be represented by, for example, the following formulas (2-6) to (2-9).

[0154] LiMPO4…(2-6) Li 2-x MPO4F...(2-7) Li2MSiO4…(2-8) LiMBO3…(2-9) In the above formulas (2-6) to (2-9), M may include, for example, at least one selected from the group consisting of Fe, Mn, and Co. In the above formula (2-7), for example, the relationship 0≦x≦2 may be satisfied.

[0155] The positive electrode active material may contain, for example, a mixture of LiMO2 (space group R-3m) and a polyanionic compound. The mixing ratio (mass ratio) of LiMO2 (space group R-3m) and the polyanionic compound may be, for example, "LiMO2 / polyanionic compound = 9 / 1 to 9 / 1," "LiMO2 / polyanionic compound = 9 / 1 to 5 / 5," or "LiMO2 / polyanionic compound = 9 / 1 to 7 / 3."

[0156] Dopant A dopant may be added to the positive electrode active material. The dopant may be diffused throughout the particle or distributed locally. For example, the dopant may be unevenly distributed on the particle surface. The dopant may be a substitutional solid solution atom or an interstitial solid solution atom. The amount of dopant added (molar fraction relative to the entire positive electrode active material) may be, for example, 0.01 to 5%, 0.1 to 3%, or 0.1 to 1%. One type of dopant may be added, or two or more types of dopants may be added. Two or more types of dopants may form a composite.

[0157] The dopant may include at least one selected from the group consisting of, for example, B, C, N, halogen, Si, Na, Mg, Al, Mn, Co, Cr, Sc, Ti, V, Cu, Zn, Ga, Ge, Se, Sr, Y, Zr, Nb, Mo, In, Pb, Bi, Sb, Sn, W, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and actinides.

[0158] For example, the set "Zr, Mg, W, Sm", the set "Ti, Mn, Nb, Si, Mo", or the set "Er, Mg" may be added to the NCA.

[0159] For example, Ti may be added to the NCM. For example, a combination of "Zr, W", a combination of "Si, W", or a combination of "Zr, W, Al, Ti, Co" may be added to the NCM.

[0160] <Surface coating> The positive electrode active material layer may contain composite particles. The composite particles include a core particle and a coating layer. The core particle contains a positive electrode active material. The coating layer covers at least a portion of the surface of the core particle. The coating layer may have a thickness of, for example, 1 to 3,000 nm, 5 to 2,000 nm, 10 to 1,000 nm, 10 to 100 nm, or 10 to 50 nm. The thickness of the coating layer can be measured, for example, from a scanning electron microscope (SEM) image of the particle cross section. That is, a sample is prepared by embedding the composite particles in a resin material. The sample is subjected to cross-section processing using an ion milling device. For example, an ion milling device manufactured by Hitachi High-Technologies Corporation, product name: ArBlade (registered trademark) 5000 (or equivalent), may be used. The cross section of the sample is observed using an SEM. For example, an SEM device manufactured by Hitachi High-Technologies Corporation, product name: SU8030 (or equivalent), may be used. The thickness of the coating layer is measured in 20 fields for each of 10 composite particles, and the arithmetic mean of the thicknesses of 200 points in total is used.

[0161] The proportion of the surface of the core particle that is covered with the coating layer is also referred to as the "coverage." The coverage may be, for example, 1% or more, 10% or more, 30% or more, 50% or more, or 70% or more. The coverage may be, for example, 100% or less, 90% or less, or 80% or less.

[0162] The coverage can be measured, for example, by XPS (X-ray Photoelectron Spectroscopy). For example, an XPS device manufactured by ULVAC-PHI, Inc., "Product Name: PHI X-tool" (or an equivalent product) may be used. A sample powder consisting of composite particles is placed in the XPS. Narrow scan analysis is performed. The measurement data is processed by analysis software. For example, analysis software manufactured by ULVAC-PHI, Inc., "Product Name: MultiPak" (or an equivalent product) may be used. Multiple elements are detected by analyzing the measurement data. The ratio of each detected element is calculated from the area of ​​each peak. The coverage can be calculated using the following formula (2-10).

[0163] θ={I1 / (I0+I1)}×100 …(2-10) θ: Coverage rate [%] I0: Ratio of elements originating from the core particle I1: Ratio of elements derived from the coating layer For example, if the core particle contains NCM, I0 indicates the total element ratio of "Ni, Co, Mn." For example, if the core particle contains NCA, I0 indicates the total element ratio of "Ni, Co, Al." For example, if the coating layer contains P and B, I1 indicates the total element ratio of "P, B."

[0164] The coating layer may contain any component. The coating layer may contain, for example, an element, an organic substance, an inorganic acid salt, an organic acid salt, a hydroxide, an oxide, a carbide, a nitride, a sulfide, a halide, or the like. The coating layer may contain, for example, B, Al, W, Zr, Ti, Co, F, lithium compounds (e.g., Li2CO3, LiHCO3, LiOH, Li2O, etc.), tungsten oxide (e.g., WO3, etc.), titanium oxide (e.g., TiO2, etc.), zirconium oxide (e.g., ZrO2, etc.), boron oxide, boron phosphate (e.g., BPO4, etc.), aluminum oxide (e.g., Al2O3, etc.), boehmite, aluminum hydroxide, phosphate (e.g., Li3PO 4、(NH4)3PO4, AlPO4, etc.), borates (e.g., Li2B4O7, LiBO3, etc.), polyacrylates (Li salts, Na salts, NH4 salts, etc.), acetates (e.g., Li salts, etc.), CMC (CMC-Na, CMC-Li, CMC-NH4, etc.), LiNbO 3、 It may contain at least one selected from the group consisting of Li2TiO3 and Li-containing halides (for example, LiAlCl4, LiTiAlF6, LiYBr6, LiYCl6, etc.).

[0165] <Hollow particles / solid particles> Hollow particles and solid particles are secondary particles (aggregates of primary particles). In a cross-sectional image of a "hollow particle," the area ratio of the cavity in the center is 30% or more of the cross-sectional area of ​​the entire particle. The ratio of the cavity in a hollow particle may be, for example, 40% or more, 50% or more, or 60% or more. In a cross-sectional image of a "solid particle," the area ratio of the cavity in the center is less than 30% of the cross-sectional area of ​​the entire particle. The ratio of the cavity in a solid particle may be, for example, 20% or less, 10% or less, or 5% or less. The positive electrode active material may be either hollow particles or solid particles. A mixture of hollow particles and solid particles may be used. The mixing ratio (mass ratio) of hollow particles to solid particles may be, for example, "hollow particles / solid particles = 1 / 9 to 9 / 1," "hollow particles / solid particles = 2 / 8 to 8 / 2," "hollow particles / solid particles = 3 / 7 to 7 / 3," or "hollow particles / solid particles = 4 / 6 to 6 / 4."

[0166] <Large particles / Small particles> The positive electrode active material may have, for example, a unimodal particle size distribution (based on the number of particles). The positive electrode active material may have, for example, a multimodal particle size distribution. The positive electrode active material may have, for example, a bimodal particle size distribution. That is, the positive electrode active material may contain large particles and small particles. When the particle size distribution is bimodal, the particle diameter corresponding to the peak top of the larger particle diameter is the particle diameter of the large particles (d L The particle size corresponding to the peak top of the smaller particle size is considered to be the particle size of the small particles (d S ) is considered as the particle size ratio (d L / dS ) may be, for example, 2 to 10, 2 to 5, or 2 to 4. L may be, for example, 8 to 20 μm or 8 to 15 μm. S may be, for example, 1 to 10 μm, or 1 to 5 μm.

[0167] For example, the particle size distribution may be subjected to peak separation processing using waveform analysis software. L ) and the peak area due to small particles (S S ) is expressed as, for example, "S L / S S =1 / 9~9 / 1", "S L / S S =5 / 5~9 / 1" or "S L / S S =7 / 3~9 / 1" is also acceptable.

[0168] The number-based particle size distribution is measured by a microscopy method. Multiple cross-sectional samples are taken from the positive electrode active material layer. The cross-sectional samples may include, for example, cross sections perpendicular to the surface of the positive electrode active material layer. For example, the surface to be observed is subjected to a cleaning treatment by ion milling or the like. The cross-sectional samples are observed using an SEM. The observation magnification is adjusted so that 10 to 100 particles fit within the observation field. The Feret diameters of all particles in the image are measured. By observing multiple cross-sectional samples, a total of 1,000 or more Feret diameters are obtained. A number-based particle size distribution is created from the 1,000 or more Feret diameters.

[0169] A bimodal particle size distribution can be formed by mixing two types of particles. The two types of particles have different particle size distributions. For example, the two types of particles may have different D50s. For example, the large particles may have a D50 of 8 to 20 μm or 8 to 15 μm. For example, the small particles may have a D50 of 1 to 10 μm or 1 to 5 μm. The ratio of the D50 of the large particles to the D50 of the small particles may be, for example, 2 to 10, 2 to 5, or 2 to 4. The mixing ratio (mass ratio) of the large particles to the small particles may be, for example, "large particles / small particles = 1 / 9 to 9 / 1," "large particles / small particles = 5 / 5 to 9 / 1," or "large particles / small particles = 7 / 3 to 9 / 1."

[0170] The large particles and the small particles may have the same composition or different compositions. For example, the large particles may be NCA and the small particles may be NCM. For example, the large particles may be NCM (0.6≦x) and the small particles may be NCM (x<0.6). The negative electrode active material (described later) may also contain large particles and small particles, similar to the positive electrode active material.

[0171] <Negative electrode> The negative electrode includes a substrate sheet 110 and an active material film 120. The active material film 120 in the negative electrode may also be referred to as a "negative electrode active material layer." The negative electrode active material layer may have a thickness of, for example, 10 to 1000 μm, 50 to 500 μm, or 100 to 300 μm. The negative electrode active material layer may have a thickness of, for example, 5 to 100 mg / cm. 2 , 10-50mg / cm 2 , or 10-30 mg / cm 2 The negative electrode active material layer may have a weight per unit area of, for example, 0.5 to 2 g / cm. 3 , 0.8~1.8g / cm 3 , 1.2~1.8g / cm 3 , or 1.4 to 1.6 g / cm 3 The negative electrode active material layer may have a density of 1000 to 15000. The negative electrode active material layer includes a negative electrode active material. The negative electrode active material layer may further include, for example, a conductive material, a binder, and the like.

[0172] Conductive materials The conductive material can form an electron conduction path in the negative electrode active material layer. The amount of the conductive material may be, for example, 0.1 to 10 parts by mass relative to 100 parts by mass of the negative electrode active material. The conductive material may contain any component. The conductive material may include, for example, at least one selected from the group consisting of AB, Ketjen Black (registered trademark), VGCF, CNT, and GF. The CNT may include at least one selected from the group consisting of single-walled CNT (SWCNT) and multi-walled CNT (MWCNT).

[0173] Binder The binder can bond the negative electrode active material layer to the current collector (substrate sheet 110). The amount of binder may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the negative electrode active material. The binder may contain any component. For example, the binder may contain at least one selected from the group consisting of SBR, acrylate butadiene rubber (ABR), sodium alginate, CMC (CMC-H, CMC-Na, CMC-Li, CMC-NH4, etc.), PAA (PAA-H, PAA-Na, PAA-Li, etc.), polyacrylonitrile (PAN), PVdF, PTFE, acrylic resin, methacrylic resin, PVP, PVA, and derivatives thereof. For example, "CMC-Na" refers to the Na salt of CMC. For example, "CMC-H" refers to acid-type CMC. The same applies to "PAA-Na" and the like.

[0174] Other ingredients The negative electrode active material layer may further contain, for example, an inorganic filler, an organic filler, a solid electrolyte, a surface modifier, a dispersant, a lubricant, a flame retardant, a protective agent, a flux, a coupling agent, an adsorbent, etc. The negative electrode active material layer may also contain, for example, a layered silicate (smectite, montmorillonite, bentonite, hectorite, etc.), an inorganic filler (solid alumina, hollow silica, boehmite, etc.), a polysiloxane compound, etc.

[0175] 《Negative electrode active material》 The negative electrode active material causes a negative electrode reaction. The negative electrode active material may be, for example, in the form of particles or a sheet. The negative electrode active material may have a D50 of, for example, 1 to 30 μm, 10 to 20 μm, or 1 to 10 μm.

[0176] <Carbon-based active material> The negative electrode active material may include, for example, a carbon-based active material. The carbon-based active material may include, for example, at least one selected from the group consisting of graphite, soft carbon, and hard carbon. "Graphite" is a general term for natural graphite and artificial graphite. The graphite may be a mixture of natural graphite and artificial graphite. The mixing ratio (mass ratio) may be, for example, "natural graphite / artificial graphite = 1 / 9 to 9 / 1," "natural graphite / artificial graphite = 2 / 8 to 8 / 2," or "natural graphite / artificial graphite = 3 / 7 to 7 / 3."

[0177] The graphite may contain a dopant. The dopant may include, for example, at least one selected from the group consisting of B, N, P, Li, and Ca. The amount of the dopant added may be, for example, 0.01 to 5%, 0.1 to 3%, or 0.1 to 1%, in mole fraction.

[0178] The surface of graphite may be coated with, for example, amorphous carbon. The surface of graphite may be coated with, for example, a different material. The different material may contain, for example, at least one selected from the group consisting of P, W, Al, and O. The different material may be, for example, Al(OH)3, AlOOH, Al2O3, WO3, Li2CO3, LiHCO 3、 and Li3PO4.

[0179] <Alloy active material> The negative electrode active material may include, for example, an alloy-based active material, such as at least one selected from the group consisting of Si, Li silicate, SiO, a Si-based alloy, Sn, SnO, and a Sn-based alloy.

[0180] SiO may be represented, for example, by the following formula (3-1).

[0181] SiO x …(3-1) In the formula, the relationship 0 < x < 2 is satisfied.

[0182] In the above formula (3-1), x may satisfy a relationship such as 0.5 ≦ x ≦ 1.5, or 0.8 ≦ x ≦ 1.2.

[0183] The Li silicate may contain, for example, at least one selected from the group consisting of Li4SiO4, Li2SiO3, Li2Si2O5, and Li8SiO6. The negative electrode active material may contain, for example, a mixture of Si and Li silicate. The mixing ratio (mass ratio) may be, for example, "Si / Li silicate = 1 / 9 to 9 / 1", "Si / Li silicate = 2 / 8 to 8 / 2", "Si / Li silicate = 3 / 7 to 7 / 3", or "Si / Li silicate = 4 / 6 to 6 / 4".

[0184] The alloy-based active material (Si, SiO, etc.) may contain an additive. The additive may be, for example, a substitutional solid solution atom or an interstitial solid solution atom. The additive may be an adherent adhering to the surface of the alloy-based active material. The adherent may be, for example, a simple substance, an oxide, a carbide, a nitride, a halide, etc. The addition amount may be, in mole fraction, for example, 0.01 to 5%, 0.1 to 3%, or 0.1 to 1%. The additive may contain, for example, at least one selected from the group consisting of Li, Na, K, Rb, Be, Mg, Ca, Sr, Fe, Ba, B, Al, Ga, In, C, Ge, Sn, Pb, N, P, As, Y, Sb, and S. That is, SiO may be doped with Mg and Na. For example, Mg silicate, Na silicate, etc. may be formed. For example, boron oxide (e.g., B2O3, etc.), yttrium oxide (e.g., Y2O3, etc.), etc. may be added to SiO.

[0185] 〈Si-C composite material〉 The negative electrode active material may include, for example, a composite material of a carbon-based active material (such as graphite) and an alloy-based active material (such as Si). A composite material containing Si and carbon may also be referred to as a "Si-C composite material." For example, Si fine particles may be dispersed within carbon particles. For example, Si fine particles may be dispersed within graphite particles. For example, Li silicate particles may be coated with a carbon material (such as amorphous carbon).

[0186] <Other active materials> The negative electrode active material is, for example, Li metal, Li-based alloy, and Li4Ti5O 12 The negative electrode active material may contain at least one selected from the group consisting of: The negative electrode active material may contain, for example, Li foil or the like.

[0187] <separator> The separator 200 has electrical insulation properties. The separator 200 may include, for example, at least one selected from the group consisting of a resin film, an inorganic particle layer, and an organic particle layer. The separator 200 may include, for example, a resin film and an inorganic particle layer.

[0188] Resin film The resin film is porous. The resin film may include, for example, a microporous film, a nonwoven fabric, etc. The resin film includes a resin skeleton. The resin skeleton may be continuous, for example, in a network form. Pores are formed in the gaps in the resin skeleton. The resin film is permeable to a liquid electrolyte. The resin film may have, for example, an average pore size of 1 μm or less. The resin film may have, for example, an average pore size of 0.01 to 1 μm, or 0.1 to 0.5 μm. The "average pore size" can be measured by mercury intrusion porosimetry. The resin film may have, for example, a pore size of 50 to 250 s / 100 cm. 3 The "Gurley value" can be measured by the Gurley test method.

[0189] The resin film may contain at least one selected from the group consisting of, for example, olefin-based resins, urethane-based resins, polyamide-based resins, cellulose-based resins, polyether-based resins, acrylic-based resins, and polyester-based resins. The resin film may contain at least one selected from the group consisting of, for example, PE, polypropylene (PP), polyamide (PA), polyamideimide (PAI), polyimide (PI), aromatic polyamide (aramid), polyphenylene ether (PPE), and derivatives thereof. The resin film may be formed by, for example, a stretching method, a phase separation method, or the like. The resin film may have a thickness of, for example, 5 to 50 μm, or 10 to 25 μm.

[0190] The resin film may have, for example, a single-layer structure. The resin film may be composed of, for example, a PE layer. The skeleton of the PE layer is formed of PE. The PE layer may have a shutdown function. The resin film may have, for example, a multi-layer structure. The resin film may include, for example, a PP layer and a PE layer. The skeleton of the PP layer is formed of PP. The resin film may have, for example, a three-layer structure. The resin film may be formed by laminating, for example, a PP layer, a PE layer, and a PP layer in this order. The thickness of the PE layer may be, for example, 5 to 20 μm. The thickness of the PP layer may be, for example, 3 to 10 μm.

[0191] 《Inorganic particle layer》 The inorganic particle layer may be formed on the surface of the resin film. The inorganic particle layer may be formed on only one side of the resin film, or on both the front and back sides. The inorganic particle layer may be formed on the surface facing the positive electrode active material layer, or on the surface facing the negative electrode active material layer. The inorganic particle layer may be formed on the surface of the positive electrode active material layer, or on the surface of the negative electrode active material layer.

[0192] The inorganic particle layer is porous. The inorganic particle layer contains inorganic particles. The inorganic particles may also be referred to as "inorganic filler." Pores are formed in the gaps between the inorganic particles. The inorganic particle layer may have a thickness of, for example, 0.5 to 10 μm, or 1 to 5 μm. The inorganic particles may contain, for example, a heat-resistant material. An inorganic particle layer containing a heat-resistant material is also referred to as an "HRL (Heat Resistance Layer)." The inorganic particles may contain at least one type selected from the group consisting of boehmite, alumina, zirconia, titania, magnesia, silica, and the like. The inorganic particles may have any shape. The inorganic particles may be, for example, spherical, rod-like, plate-like, fibrous, or the like. The inorganic particles may have a D50 of, for example, 0.1 to 10 μm, or 0.5 to 3 μm. The inorganic particle layer may further contain a binder. The binder may contain, for example, at least one selected from the group consisting of acrylic resins, polyamide resins, fluorine resins, aromatic polyether resins, and liquid crystal polyester resins.

[0193] 《Organic particle layer》 The separator 200 may include, for example, an organic particle layer. The separator 200 may include, for example, an organic particle layer instead of a resin film. The separator 200 may include, for example, an organic particle layer instead of an inorganic particle layer. The separator 200 may include both a resin film and an organic particle layer. The separator 200 may include both an inorganic particle layer and an organic particle layer. The separator 200 may include a resin film, an inorganic particle layer, and an organic particle layer.

[0194] The organic particle layer may have a thickness of, for example, 0.1 to 50 μm, 0.5 to 20 μm, 0.5 to 10 μm, or 1 to 5 μm. The organic particle layer contains organic particles. The organic particles may also be referred to as "organic filler." The organic particles may contain a heat-resistant material. The organic particles may contain at least one selected from the group consisting of, for example, PE, PP, PTFE, PI, PAI, PA, and aramid. The organic particles may be, for example, spherical, rod-like, plate-like, fibrous, or the like. The organic particles may have a D50 of, for example, 0.1 to 10 μm or 0.5 to 3 μm.

[0195] Separator 200 may, for example, include a mixed layer, which includes both inorganic and organic particles.

[0196] <Liquid electrolyte> The battery 1000 may include, for example, a liquid electrolyte. The liquid electrolyte may include, for example, an electrolytic solution. The electrolytic solution includes a solvent and a solute.

[0197] 《Solute》 The concentration of the solute may be, for example, 0.5 to 1 mol / L, 1 to 1.5 mol / L, 1.5 to 2 mol / L, 2 to 2.5 mol / L, or 2.5 to 3 mol / L. The solute includes a supporting salt (Li salt). The solute may include, for example, an inorganic acid salt, an imide salt, an oxalate complex, a halide, or the like. The solute may include, for example, at least one selected from the group consisting of LiPF6, LiBF4, LiClO4, LiAsF6, LiSbF6, LiN(SO2F)2 "LiFSI", LiN(SO2CF3)2 "LiTFSI", LiB(C2O4)2 "LiBOB", LiBF2(C2O4) "LiDFOB", LiPF2(C2O4)2 "LiDFOP", LiPO2F2, FSO3Li, LiI, LiBr, and derivatives thereof.

[0198] <Carbonate solvent> The electrolytic solution may contain, for example, a carbonate-based solvent (carbonate ester-based solvent). The solvent may contain, for example, a cyclic carbonate, a chain carbonate, a fluorinated carbonate, or the like. The solvent may contain, for example, at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), monofluoroethylene carbonate (FEC), difluoroethylene carbonate, 4,4-difluoroethylene carbonate, trifluoroethylene carbonate, perfluoroethylene carbonate, fluoropropylene carbonate, difluoropropylene carbonate, and derivatives thereof.

[0199] The solvent may contain a cyclic carbonate (EC, PC, FEC, etc.) and a chain carbonate (EMC, DMC, DEC, etc.). The mixing ratio (volume ratio) of the cyclic carbonate to the chain carbonate may be, for example, "cyclic carbonate / chain carbonate = 1 / 9 to 4 / 6," "cyclic carbonate / chain carbonate = 2 / 8 to 3 / 7," or "cyclic carbonate / chain carbonate = 3 / 7 to 4 / 6."

[0200] The solvent may contain a cyclic carbonate (EC, PC, etc.) and a fluorinated cyclic carbonate (FEC, etc.). The mixing ratio (volume ratio) of the cyclic carbonate to the fluorinated cyclic carbonate may be, for example, "cyclic carbonate / fluorinated cyclic carbonate = 99 / 1 to 90 / 10", "cyclic carbonate / fluorinated cyclic carbonate = 9 / 1 to 1 / 9", "cyclic carbonate / fluorinated cyclic carbonate = 9 / 1 to 7 / 3", or "cyclic carbonate / fluorinated cyclic carbonate = 3 / 7 to 1 / 9".

[0201] The solvent may contain, for example, EC, FEC, EMC, DMC, and DEC. The volume ratio of each component may satisfy, for example, the relationship represented by the following formula (4-1).

[0202] V EC +V FEC +V EMC +V DMC +V DEC =10 …(4-1) In the formula, V EC , V FEC , V EMC , V DMC , V DEC indicates the volume ratio of EC, FEC, EMC, DMC, and DEC, respectively. 1≦V EC ≦4, 0≦V FEC ≦3, V EC +V FEC ≦4, 0≦V EMC ≦9, 0≦V DMC ≦9, 0≦V DEC ≦9, 6≦V EMC +V DMC +V DEC ≦9 The relationship is satisfied.

[0203] In the above formula (4-1), For example, 1 ≤ V EC ≦2, or 2≦V EC The relationship ≦3 may be satisfied. For example, 1 ≤ V FEC ≦2, or 2≦V FEC The relationship ≦4 may be satisfied. For example, 3≦V EMC ≦4 or 6≦V EMC The relationship ≦8 may be satisfied. For example, 3≦V DMC ≦4 or 6≦V DMC The relationship ≦8 may be satisfied. For example, 3≦V DEC ≦4 or 6≦V DEC The relationship ≦8 may be satisfied.

[0204] The solvent may have a composition, for example, in volume ratios of "EC / EMC=3 / 7," "EC / DMC=3 / 7," "EC / FEC / DEC=1 / 2 / 7," "EC / DMC / EMC=3 / 4 / 3," "EC / DMC / EMC=3 / 3 / 4," "EC / FEC / DMC / EMC=2 / 1 / 4 / 3," "EC / FEC / DMC / EMC=1 / 2 / 4 / 3," "EC / FEC / DMC / EMC=2 / 1 / 3 / 4," or "EC / FEC / DMC / EMC=1 / 2 / 3 / 4."

[0205] 《Ether solvents》 The electrolyte may contain an ether-based solvent, such as at least one selected from the group consisting of tetrahydrofuran (THF), 1,4-dioxane (DOX), 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), hydrofluoroether (HFE), ethylglyme, triglyme, tetraglyme, and derivatives thereof.

[0206] Additives The electrolyte may contain any additive. The amount of additive (mass fraction relative to the total amount of the electrolyte) may be, for example, 0.01 to 5%, 0.05 to 3%, or 0.1 to 1%. The additive may include, for example, an SEI (Solid Electrolyte Interphase) formation accelerator, an SEI formation inhibitor, a gas generator, an overcharge inhibitor, a flame retardant, an antioxidant, an electrode protectant, a surfactant, etc.

[0207] Examples of the additives include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), 1,3-propane sultone (PS), tert-amylbenzene, 1,4-di-tert-butylbenzene, biphenyl (BP), cyclohexylbenzene (CHB), ethylene sulfite (ES), propane sultone (PS), ethylene sulfate (DTD), γ-butyrolactone, phosphazene compounds, carboxylic acid esters (e.g., methyl formate (MF), methyl acetate (MA), methyl propionate (MP), diethyl malonate (DEM), etc.), fluorobenzenes (e.g., monofluorobenzene (FB), 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, etc.), fluorotoluenes (e.g., 2-fluorotoluene, 3-fluorotoluene, 4-fluorotoluene, 2,3-difluorotoluene, 2,4-difluorotoluene, 2,5-difluorotoluene, 2,6-difluorotoluene, 3,4-difluorotoluene, octafluorotoluene, etc.), benzotrifluorides (e.g., benzotrifluoride, 2-fluorobenzotrifluoride, 3-fluorobenzotrifluoride, 4-fluorobenzotrifluoride, 2-methylbenzotrifluoride, 3-methylbenzotrifluoride, 4-methylbenzotrifluoride, etc.), fluoroxylenes (e.g., 3-fluoro-o-xylene, 4-fluoro-o-xylene, 2-fluoro-m-xylene, 5-fluoro-m-xylene, etc.), sulfur-containing heterocyclic compounds (e.g., benzothiazole, 2-methylbenzotrifluoride, The solvent may contain at least one selected from the group consisting of solvents such as benzothiazole, tetrathiafulvane, etc., nitrile compounds (e.g., adiponitrile, succinonitrile, etc.), phosphate esters (e.g., trimethyl phosphate, triethyl phosphate, etc.), carboxylic acid anhydrides (e.g., acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, benzoic anhydride, etc.), alcohols (e.g., methanol, ethanol, n-propyl alcohol, ethylene glycol, diethylene glycol monomethyl ether, etc.), and derivatives thereof.

[0208] The components described above as solutes and solvents may be used as minor components (additives). The additives may include, for example, at least one selected from the group consisting of LiBF, LiFSI, LiTFSI, LiBOB, LiDFOB, LiDFOP, LiPOF, FSOLi, LiI, LiBr, HFE, DOX, PC, FEC, and derivatives thereof.

[0209] Ionic liquids The liquid electrolyte may contain an ionic liquid. The liquid electrolyte may contain, for example, at least one selected from the group consisting of sulfonium salts, ammonium salts, pyridinium salts, piperidinium salts, pyrrolidinium salts, morpholinium salts, phosphonium salts, imidazolium salts, and derivatives thereof.

[0210] <Gel electrolyte> The battery 1000 may include, for example, a gel electrolyte. The gel electrolyte may include a liquid electrolyte and a polymer material. The polymer material may form a polymer matrix. The polymer material may include, for example, at least one selected from the group consisting of PVdF, PVdF-HFP, PAN, PVdF-PAN, polyethylene oxide (PEO), polyethylene glycol (PEG), and derivatives thereof.

[0211] <Solid electrolyte> The battery 1000 may include, for example, a solid electrolyte. The solid electrolyte can form an ion conduction path in the electrode active material layer. The solid electrolyte may be, for example, particulate. The solid electrolyte may have a D50 of, for example, 0.1 to 3 μm. The D50 of the solid electrolyte may be, for example, 1 μm or less, or 0.5 μm or less. The amount of solid electrolyte in the electrode active material layer may be, for example, 1 to 200 parts by volume, 50 to 150 parts by volume, or 50 to 100 parts by volume per 100 parts by volume of the electrode active material.

[0212] 《Sulfide solid electrolyte》 The electrode active material layer may include, for example, a sulfide solid electrolyte. The sulfide solid electrolyte may be, for example, glass ceramics or argyrodite. Examples of sulfide solid electrolytes include LiI-LiBr-Li3PS4, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2O-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-GeS2-P2S5, Li2S-P2S5, and Li 10 GeP2S 12 , Li4P2S6, Li7P3S 11 , Li3PS4, Li7PS6, and Li6PS5X (X = Cl, Br, I).

[0213] For example, "LiI-LiBr-Li3PS4" represents a sulfide solid electrolyte formed by mixing LiI, LiBr, and Li3PS4 in any molar ratio. For example, the sulfide solid electrolyte may be formed by a mechanochemical method. "Li2S-P2S5" contains Li3PS4. Li3PS4 can be formed, for example, by mixing Li2S and P2S5 at "Li2S / P2S5 = 75 / 25 (molar ratio)".

[0214] 《Other Solid Electrolytes》 In addition to the sulfide solid electrolyte, the electrode active material layer may further contain other solid electrolytes. Hereinafter, for convenience, the sulfide solid electrolyte may also be referred to as the "first solid electrolyte", and the other solid electrolytes may also be referred to as the "second solid electrolyte". The volume ratio of the first solid electrolyte to the second solid electrolyte may be, for example, "First Solid Electrolyte / Second Solid Electrolyte = 1 / 99 to 99 / 1", "First Solid Electrolyte / Second Solid Electrolyte = 1 / 9 to 9 / 1", or "First Solid Electrolyte / Second Solid Electrolyte = 3 / 7 to 7 / 3". The first solid electrolyte and the second solid electrolyte may be subjected to a composite treatment.

[0215] The second solid electrolyte may contain, for example, at least one selected from the group consisting of halide solid electrolytes, oxide solid electrolytes, hydride solid electrolytes, and nitride solid electrolytes.

[0216] The halide solid electrolyte may be represented, for example, by the following formula (5-1). Li 6-na M a X6…(5-1) In the formula, n represents the oxidation number of M. M may contain, for example, an atom having an oxidation number of +3. M may contain, for example, an atom having an oxidation number of +4. M may contain, for example, at least one selected from the group consisting of Y, Al, Ti, Zr, Ca, and Mg. a may satisfy the relationship 0 < a < 2. X may contain, for example, at least one selected from the group consisting of F, Cl, Br, and I.

[0217] The halide solid electrolyte may be represented by, for example, the following formula (5-2): Li 3-a Ti a Al 1-a F6…(5-2) In the formula, the relationship 0≦a≦1 is satisfied. a may satisfy the relationship 0≦a≦0.1, 0.1≦a≦0.2, 0.2≦a≦0.3, 0.3≦a≦0.4, 0.4≦a≦0.5, 0.5≦a≦0.6, 0.6≦a≦0.7, 0.7≦a≦0.8, 0.8≦a≦0.9, or 0.9≦a≦1, for example.

[0218] The halide solid electrolyte may be represented by, for example, the following formula (5-3): Li3YCl a Br b I 6-a-b …(5-3) In the formula, the relationship 0≦a+b≦6 is satisfied. a may satisfy the relationship 0≦a≦1, 1≦a≦2, 2≦a≦3, 3≦a≦4, 4≦a≦5, or 5≦a≦6, for example. b may satisfy the relationship 0≦b≦1, 1≦b≦2, 2≦b≦3, 3≦b≦4, 4≦b≦5, or 5≦b≦6, for example.

[0219] The oxide solid electrolyte is, for example, LiNbO3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, La 2 / 3-x Li 3x TiO3 and Li7La3Zr2O 12 The hydride solid electrolyte may contain, for example, LiBH4, etc. The nitride solid electrolyte may contain, for example, Li3N, Li3BN2, etc.

[0220] 《Solid electrolyte layer》 When the battery 1000 is an all-solid-state battery, the separator 200 includes a solid electrolyte layer. The solid electrolyte layer may have a thickness of, for example, 1 to 50 μm.

[0221] The solid electrolyte layer includes a solid electrolyte. The solid electrolyte layer may further include, for example, a binder. The solid electrolyte may be the same or different between the solid electrolyte layer and the electrode active material layer. The solid electrolyte layer may include, for example, at least one selected from the group consisting of a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, a hydride solid electrolyte, and a nitride solid electrolyte. The amount of binder may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the solid electrolyte. The binder may be the same or different between the solid electrolyte layer and the electrode active material layer.

[0222] The solid electrolyte layer may have a single-layer structure or a multi-layer structure. The solid electrolyte layer may have, for example, a 2- to 5-layer structure. For example, the solid electrolytes in each layer may be different from each other. For example, the densities in each layer may be different from each other. For example, the particle sizes (e.g., D50) of the solid electrolytes in each layer may be different from each other.

[0223] For example, the solid electrolyte layer may include a first layer 210 and a second layer 220. The first layer 210 is in contact with the first electrode 101. The second layer 220 is in contact with the second electrode 102. The thickness ratio between the first layer 210 and the second layer 220 may be, for example, "first layer / second layer=1 / 9 to 9 / 1" or "first layer / second layer=3 / 7 to 7 / 3".

[0224] The first layer 210 may have a different composition from the second layer 220. For example, the first layer 210 may include a sulfide solid electrolyte, and the second layer 220 may include a halide solid electrolyte. For example, the first layer 210 may include a halide solid electrolyte, and the second layer 220 may include a sulfide solid electrolyte. The first layer 210 may include both a sulfide solid electrolyte and a halide solid electrolyte. The second layer 220 may include both a sulfide solid electrolyte and a halide solid electrolyte. The volume ratio of the halide solid electrolyte to the sulfide solid electrolyte in the first layer 210 (first volume ratio) may be greater than the volume ratio of the halide solid electrolyte to the sulfide solid electrolyte in the second layer 220 (second volume ratio). The first volume ratio may be smaller than the second volume ratio.

[0225] <Battery configuration> FIG. 9 is Table 1 showing the first battery configuration. FIG. 10 is Table 2 showing the second battery configuration. FIG. 11 is Table 3 showing the third battery configuration. In each table, when multiple materials are listed in a box, the listing includes each material alone and combinations thereof. For example, when materials "α, β, γ" are listed in a box, the listing indicates "at least one selected from the group consisting of α, β, and γ." Any element may be extracted from the first to third battery configurations and combined in any manner. Battery 1000 may, for example, include the first to third battery configurations. [Example]

[0226] <<Electrode manufacturing>> An attempt was made to manufacture an electrode using a manufacturing system 20 (see FIG. 2). Hereinafter, "length" refers to the dimension in the length direction (Y-axis direction), and "width" refers to the dimension in the width direction (X-axis direction).

[0227] <No.1> (a) Preparation of the base sheet An Al foil (thickness: 40 μm, width: 251 mm) was prepared as the base sheet 110. In the surface-roughening device 21 (third roll nip G3), the base sheet 110 was intermittently roughened. That is, a first region 111 and a second region 112 were formed. The arithmetic mean roughness of the first region 111 (unprocessed portion) was 0.05 μm. The arithmetic mean roughness of the second region 112 (processed portion) was 7.5 to 12.5 μm. The length of the first region 111 was 302 mm. The length of the second region 112 was 27 mm. The widths of the first region 111 and the second region 112 were both 251 mm.

[0228] (b) Preparation of the active material film (b1) Preparation of wet powder In a stirring granulator, an active material (NCM), a conductive material (CNT), a binder (PVdF), and a liquid (NMP) were mixed to prepare wet powder 10. The solid content of wet powder 10 was 89%. The solid content ratio was "active material / conductive material / binder = 97.3 / 1.5 / 1.2 (mass ratio)."

[0229] (b2) Film formation The wet powder 10 was supplied to the first roll nip G1 to form an active material film 120 (width: 219 mm). The film formation conditions were as follows.

[0230] Film formation conditions First roll gap G1: 220 μm Rotation speed of first roll 23a (ω1): 0.75 rpm Arithmetic mean roughness of the first roll 23a: 0 to 10 μm Rotation speed of second roll 23b (ω2): 2 rpm Arithmetic mean roughness of the second roll 23b: 0 to 10 μm

[0231] (c) Paste The second roll 23b supplied the active material film 120 to the second roll nip G2. The conveying device 22 supplied the base sheet 110 to the second roll nip G2. In the second roll nip G2, the active material film 120 was attached to the base sheet 110. The active material film 120 selectively adhered to the first region 111. After attachment, the active material film 120 had a width of 219 mm and a length of 302 mm.

[0232] Paste conditions (transfer conditions) Second roll gap G2: 130 μm Rotation speed of second roll 23b (ω2): 2 rpm Rotation speed of the third roll 23c (ω3): 5 rpm

[0233] <No.2> A resin adhesive tape was prepared as a mask. The adhesive tape had an adhesive applied to one side. The mask was attached to the base sheet 110 in an area (width: 251 mm, length: 27 mm) corresponding to the second area 112. Active material films 120 were continuously attached to the base sheet 110 using an attachment device 23. After attachment, the mask was peeled off to form non-coated areas. After the mask was peeled off, the active material film 120 had a width of 219 mm and a length of 302 mm.

[0234] <<Evaluation>> <Shape accuracy> Five electrodes 100 were manufactured using the manufacturing method according to No. 1. Five electrodes 100 were manufactured using the manufacturing method according to No. 2. FIG. 12 is a first graph showing shape accuracy. FIG. 13 is a second graph showing shape accuracy. The first graph shows the accuracy index at the starting end of the active material film 120. The second graph shows the accuracy index at the terminal end of the active material film 120. In the transport direction of the active material film 120 in the manufacturing system 20, the front end is the starting end and the rear end is the terminal end. It is considered that the smaller the accuracy index, the higher the shape accuracy. There is a tendency for shape accuracy to decrease at the terminal end compared to the starting end.

[0235] No. 1 showed higher shape accuracy than No. 2. No. 1 showed an accuracy index of 1.5 mm or less on both the starting and ending sides.

[0236] <Battery performance> Small test batteries were manufactured. The outer casing of the test batteries was a pouch made of aluminum laminate film. Test battery No. 1 included electrodes manufactured by the manufacturing method No. 1. Test battery No. 2 included electrodes manufactured by the manufacturing method No. 2. Three test batteries No. 1 and No. 2 were manufactured. The internal resistance was measured by the IV method after 10 seconds of discharge and after 10 seconds of charge. Furthermore, the internal resistance was measured by the IV method after 0.1 seconds of discharge and after 0.1 seconds of charge. The current time rate was 1C. A time rate of 1C discharges the rated capacity of the test battery in one hour.

[0237] FIG. 14 is a graph showing battery performance. The bar graph shows the average value of the internal resistance of three test batteries. The error bars show the variation in internal resistance. Test battery No. 1 showed an internal resistance equivalent to that of test battery No. 2. Therefore, it is considered that the second region 112 (rough surface) of the base sheet 110 has little effect on battery performance.

[0238] The test battery No. 1 tends to have smaller error bars than the test battery No. 2. This is thought to be due to the high shape precision, which contributes to stable battery performance. [Explanation of symbols]

[0239] 1 smooth surface, 2 rough surface, 10 wet powder, 20 manufacturing system, 21 roughening device, 21a first rough surface roll, 21b second rough surface roll, 22 conveying device, 23 bonding device, 23a first roll, 23b second roll, 23c third roll, 24 recovery device, 24a scraper, 24b suction device, 100 electrode, 101 first electrode, 102 second electrode, 110 base sheet, 110a first main surface, 110b second main surface, 111 first region, 112 second region, 113 boundary line, 120 active material film, 120a upper portion, 120b lower portion, 120e end region, 121 upper surface, 122 side surface, 123 bottom surface, 130 current collecting member, 200 separator, 210 first layer, 220 Second layer, 500 power generating element, 1000 battery, G1 first roll nip, G2 second roll nip, G3 third roll nip, VI region.

Claims

1. (a) providing a substrate sheet; (b) providing an active material film; and (c) attaching the active material film to the substrate sheet by passing the substrate sheet and the active material film through a nip; Including, the base sheet includes a first region and a second region, the second region has a larger arithmetic mean roughness than the first region, the second region is adjacent to the first region, In the step (c), the active material film is selectively attached to the first region out of the first region and the second region; The step (a) includes forming the second region by roughening the base sheet; The roughening process includes pressing a roughened roll against the substrate sheet; and The surface of the rough-surfaced roll has one or more smooth surfaces and one or more rough surfaces formed thereon. Electrode manufacturing method.

2. a ratio of the arithmetic mean roughness of the second region to the arithmetic mean roughness of the first region is 2 or more; A method for manufacturing the electrode according to claim 1.

3. a ratio of the arithmetic mean roughness of the second region to the arithmetic mean roughness of the first region is 10 or more; The method for manufacturing the electrode according to claim 2 .

4. a ratio of the arithmetic mean roughness of the second region to the arithmetic mean roughness of the first region is 100 or more; The method for manufacturing the electrode according to claim 3 .

5. The (b) is (b1) providing a wet powder comprising an active material and a binder; and (b2) forming the wet powder into the active material film; Including, The method for manufacturing the electrode according to any one of claims 1 to 4.

6. The base sheet has a strip-like planar shape, and The first regions and the second regions are alternately arranged in the longitudinal direction of the base sheet. The method for manufacturing the electrode according to any one of claims 1 to 4.

7. (d) joining a current collecting member to the second region by ultrasonic bonding; further comprising: The method for manufacturing the electrode according to any one of claims 1 to 4.

8. A manufacturing system for manufacturing an electrode by attaching an active material film to a substrate sheet, comprising: roughening equipment, a conveying device, and Pasting device, Including, the surface-roughening device is configured to roughen a portion of the base sheet; the conveying device is configured to convey the base sheet from the surface roughening device to the bonding device, the attachment device is configured to attach the active material film to the base sheet by passing the base sheet and the active material film through a nip between rolls; The roughening process is performed on a part of the base sheet to form a first region and a second region, the second region has a larger arithmetic mean roughness than the first region, After the base sheet and the active material film have passed through the nip, the basis weight of the active material film in the first region is greater than the basis weight of the active material film in the second region, and the range of the basis weight of the active material film in the second region includes zero, the surface roughening device includes a surface roughening roll; The surface of the rough-surfaced roll has one or more smooth surfaces and one or more rough surfaces formed thereon. Manufacturing system.

9. further comprising a recovery device; the recovery device is configured to recover a remaining portion of the active material film that is not attached to the base sheet. The manufacturing system of claim 8 .

10. Base sheet, an active material film, and current collecting member, Including, the base sheet includes a first region and a second region, the second region has a larger arithmetic mean roughness than the first region, the second region is adjacent to the first region, the active material film includes an active material and a binder; The active material film is disposed in the first region, and the current collecting member is joined to the second region, Formula (1-1): Ra 1 <0.5D < Ra 2 (1-1) Fulfilling the relationship, In the formula (1-1), Ra 1 represents the arithmetic mean roughness of the first region, Ra2 represents the arithmetic mean roughness of the second region, 0.5D represents 0.5 times the average diameter of the active material, The first region has an arithmetic mean roughness of 0.5 μm or less, and The second region has an arithmetic mean roughness of 5 to 15 μm. electrode.

11. In plan view, the boundary line between the first region and the second region extends linearly, the active material film includes an edge region, the end region extends along the boundary line; and In a direction perpendicular to the boundary line, the maximum distance between the end region and the boundary line is 1.5 mm or less.

11. The electrode of claim 10.

12. In cross section, the end region includes a top surface, a side surface, and a bottom surface; the bottom surface is in contact with the base sheet, the top surface is the opposite surface of the bottom surface, the side surface connects the bottom surface and the top surface; and The angle between the side surface and the bottom surface is 45 to 90 degrees.

12. The electrode of claim 11.

13. The active material film has the formula (1-2): ０．８≦α／β≦１．５ …（１－２） Fulfilling the relationship, In the formula (1-2), α represents the mass concentration of a specific element derived from the binder in the upper portion, β represents the mass concentration of the specific element in the lower part, the upper portion and the lower portion are divided by dividing the active material film into two equal parts in a thickness direction; and The lower portion is located between the upper portion and the base sheet.

13. An electrode according to any one of claims 10 to 12.

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