Apparatus for manufacturing electrode active material layer and method for manufacturing electrode active material layer using the same

Abstract

This electrode active material layer manufacturing device comprises a supply unit for supplying granulated particles, a conveying unit for conveying the granulated particles, a supporting unit for supporting the granulated particles, a squeegee unit which is disposed on the supporting unit with a gap therebetween, to form a granulated particle layer by leveling the granulated particles, a rolling unit for forming the electrode active material layer by rolling the granulated particle layer, and a pair of plate-shaped stock guide units, wherein: the pair of stock guide units are disposed parallel to side surfaces of the squeegee unit, independent of one another; on both an upstream side and a downstream side in a conveying portion of the granulated particles, upstream side end portions of the stock guide units are positioned further toward the upstream side than the gap portion between the supporting unit and the squeegee unit, and downstream side end portions of the stock guide units are positioned further toward the downstream side than the gap portion; and the pair of stock guide units are disposed such that a distance between the side surfaces of the pair of stock guide units corresponds to a width of the electrode active material layer.

Description

[Technical Field]

[0001] This invention relates to an apparatus for manufacturing an electrode active material layer and a method for manufacturing an electrode active material layer using the same. [Background technology]

[0002] For example, one known manufacturing technique for electrode active material layers used in batteries such as lithium-ion batteries involves transporting a substrate, supplying granulated particles containing electrode active material and a binder onto the transported substrate, leveling the granulated particles using a roll-shaped squeegee, and then rolling them with a rolling mill (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-115569 [Overview of the project] [Problems that the invention aims to solve]

[0004] As described above, in a method for manufacturing an electrode active material layer, if the process includes a step of leveling the granulated particles using a squeegee, the granulated particles may flow outward beyond the target molding width of the electrode active material layer, resulting in insufficient smoothness at the edges of the obtained electrode active material layer (edge ​​smoothness). Furthermore, improvement is needed in the yield of granulated particles.

[0005] The present invention was devised in view of the above-mentioned problems, and aims to provide an apparatus for manufacturing an electrode active material layer that can produce an electrode active material layer with a good yield of granulated particles and good edge smoothness, and a method for manufacturing an electrode active material layer using the same. [Means for solving the problem]

[0006] The inventors of the present invention conducted studies to solve the above problems. As a result, they conceived the idea that the above problems could be solved by arranging plate-shaped stock guides having a specific shape on both sides of the squeegee portion, and thus completed the present invention. In other words, the present invention includes the following:

[0007] [1] An electrode active material layer manufacturing apparatus comprising: a supply unit for supplying granulated particles containing electrode active material and a binder; a transport unit for transporting the granulated particles supplied by the supply unit; a support unit for supporting the granulated particles transported by the transport unit; a squeegee unit disposed on the support unit with a gap between them, for leveling the granulated particles and forming a granulated particle layer; and a rolling unit for rolling the granulated particle layer and forming an electrode active material layer, wherein the electrode active material layer manufacturing apparatus has a pair of plate-shaped stock guide units, each of the pair of stock guide units is independently arranged parallel to the side surface of the squeegee unit, and the upstream end of each stock guide unit is located upstream of the gap between the support unit and the squeegee unit, and the downstream end of each stock guide unit is located downstream of the gap, and the distance between the side surfaces of the pair of stock guide units corresponds to the width of the electrode active material layer. [2] The apparatus for manufacturing an electrode active material layer according to [1], wherein the support portion is roll-shaped, the pair of stock guide portions are arranged on the support portion, each of the pair of stock guide portions has a curved surface on the support portion side independently, and the ratio (R1 / R0) of the radius of curvature R1 of the curved surface of the stock guide portion to the radius of curvature R0 of the curved surface of the roll of the support portion is 0.95 or more and 1.10 or less. [3] The apparatus for manufacturing an electrode active material layer according to [1], wherein the transport section is provided on the support section, the transport section and the stock guide section are in contact, and the contact length of the stock guide section with respect to the circumference of the support section is 7.5% or more and 17.5% or less. [4] The transport section is provided on the support section, and there is a gap between the transport section and the stock guide section, and the size of the gap is the average particle size (D 50A manufacturing apparatus for the electrode active material layer described in [1] or [2], wherein the amount is 70% or less of the above. [5] The apparatus for manufacturing an electrode active material layer according to any one of the items [1] to [4], wherein each of the pair of stock guide sections has an independent coefficient of friction of 0.50 or less. [6] A method for manufacturing an electrode active material layer using an electrode active material layer manufacturing apparatus described in any one of [1] to [5], comprising: a step of supplying the granulated particles from the supply unit (A); a step of transporting the supplied granulated particles (B); a step of placing the transported granulated particles on a support unit, leveling the granulated particles using the squeegee unit to form the granulated particle layer between the sides of the pair of stock guide units (C); and a step of rolling the granulated particle layer using the rolling unit to form the electrode active material layer (D). [7] A method for producing an electrode active material layer according to [6], further comprising a step of supplying a substrate before step (A), wherein steps (A) to (D) are performed on the substrate. [8] The method for producing an electrode active material layer according to [7], wherein, before step (A), a binder coating liquid containing a binder is applied to the surface of the substrate, and in step (A), the granulated particles are supplied to the surface of the substrate to which the binder coating liquid has been applied. [9] The method for producing an electrode active material layer according to [6], further comprising a step of supplying a substrate after step (C), wherein in step (D), the electrode active material layer is transferred onto the substrate by using the rolling unit to roll the granulated particle layer formed on the support unit between the supplied substrate and the support unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an apparatus for manufacturing an electrode active material layer that can produce an electrode active material layer with a good yield of granulated particles and good edge smoothness, and a method for manufacturing an electrode active material layer using the same. [Brief explanation of the drawing]

[0009] [Figure 1]FIG. 1 is a side view schematically showing a manufacturing apparatus for an electrode active material layer according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view schematically showing a support part, a squeegee part, and a stock guide part in the manufacturing apparatus shown in FIG. 1. [Figure 3] FIG. 3 is a top view seen from the squeegee part side of a conveyance part, a support part, a squeegee part, a stock guide part, and a rolling part in the manufacturing apparatus shown in FIG. 1. [Figure 4] FIG. 4 is a side view schematically showing a conveyance part, a support part, a squeegee part, and a stock guide part in the manufacturing apparatus shown in FIG. 1. [Figure 5] FIG. 5 is a side view schematically showing a modification example of a manufacturing apparatus for an electrode active material layer according to a first embodiment of the present invention. [Figure 6] FIG. 6 is a side view schematically showing a conveyance part, a support part, a squeegee part, and a stock guide part in the manufacturing apparatus shown in FIG. 5. [Figure 7(a)] FIG. 7(a) is a side view schematically showing an example of a fixing method of a stock guide part. [Figure 7(b)] FIG. 7(b) is a side view schematically showing another example of a fixing method of a stock guide part. [Figure 8] FIG. 8 is a side view schematically showing a manufacturing apparatus for an electrode active material layer according to a second embodiment of the present invention. [Figure 9] FIG. 9 is a side view schematically showing a manufacturing apparatus for an electrode active material layer according to another embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope. The components of the embodiments shown below can be combined as appropriate. Also, in the drawings, the same components are denoted by the same reference numerals, and the description thereof may be omitted.

[0011] Unless otherwise specified, "upstream" and "downstream" refer to the upstream and downstream in the transport direction of the granulated particles in the method for manufacturing an electrode active material layer.

[0012] In the following description, unless otherwise specified, the directions of the elements such as "parallel", "perpendicular", and "orthogonal" may include errors within a range that does not impair the effects of the present invention, for example, within a range of ±5°.

[0013] [1. Overview of the manufacturing apparatus for an electrode active material layer] The manufacturing apparatus for an electrode active material layer according to the present invention includes a supply unit that supplies granulated particles containing an electrode active material and a binder, a transport unit that transports the granulated particles supplied by the supply unit, a support unit that supports the granulated particles transported by the transport unit, a squeegee unit that is disposed with a gap on the support unit to level the granulated particles and form a granulated particle layer, and a rolling unit that rolls the granulated particle layer to form an electrode active material layer. The manufacturing apparatus for an electrode active material layer has a pair of plate-shaped stock guide units. The pair of stock guide units are each independently disposed parallel to the side surface of the squeegee unit, and the upstream end of the stock guide unit is located upstream of the position of the gap between the support unit and the squeegee unit, and the downstream end of the stock guide unit is located downstream of the position of the gap. The distance between the side surfaces of the pair of stock guide units is arranged to correspond to the width of the electrode active material layer.

[0014] According to the present invention, since the pair of stock guide units are each independently disposed parallel to the side surface of the squeegee unit, and the upstream end of the stock guide unit is located upstream of the position of the gap between the support unit and the squeegee unit, and the downstream end of the stock guide unit is located downstream of the position of the gap, when the granulated particles pass through the gap provided between the support unit and the squeegee unit, it is possible to suppress a decrease in the edge smoothness due to the granulated particles flowing outward.

[0015] Furthermore, since the pair of stock guide sections are positioned such that the distance between their sides corresponds to the width of the electrode active material layer, when leveling the granulated particles, it is possible to level the granulated particles to the target molding width of the electrode active material layer and adjust the basis weight of the granulated particles in the width direction. In particular, it is possible to reduce the variation in basis weight between the center and the edges in the width direction. As a result, uneven rolling due to variations in basis weight can be suppressed, and the edge strength of the electrode active material layer can also be improved.

[0016] Furthermore, by arranging a plate-shaped stock guide section, the outward flow of granulated particles can be suppressed, thereby improving the yield of granulated particles.

[0017] The electrode active material layer manufacturing apparatus of the present invention is not particularly limited as long as it has a supply unit, a transport unit, a support unit, a squeegee unit, a pair of plate-shaped stock guide units, and a rolling unit. However, preferred embodiments include a configuration in which a substrate supply unit and a substrate transport unit are further located upstream of the supply unit (first embodiment), and a configuration in which a substrate supply unit and a substrate transport unit are further located downstream of the squeegee unit (second embodiment). The electrode active material layer manufacturing apparatus will be described below using these embodiments as examples.

[0018] [1.1. Apparatus for manufacturing electrode active material layer according to the first embodiment] Figure 1 is a schematic side view showing an electrode active material layer manufacturing apparatus according to one embodiment of the present invention. The electrode active material layer manufacturing apparatus 100a shown in Figure 1 has a supply unit 10, a transport unit 20, a support unit 30, a squeegee unit 40 and a pair of plate-shaped stock guide units 50, and a rolling unit 60, in this order from upstream in the transport direction of granulated particles 2. The manufacturing apparatus 100a includes a base material supply unit 21 located upstream of the supply unit 10, and a base material transport unit 22 that transports the base material 1 supplied from the base material supply unit 21 to the rolling unit 60, and the base material transport unit 22 including the base material 1 also serves as the transport unit 20 for granulated particles 2. In addition, in the manufacturing apparatus 100a, a part of the transport unit 20 is usually located on the support unit 30.

[0019] The manufacturing apparatus 100a may further include a coating unit 80 between the substrate supply unit 21 and the supply unit 10, if necessary, for coating the substrate 1 with a binder coating liquid containing a binder. Furthermore, the manufacturing apparatus 100a may further include a recovery unit 70 downstream of the rolling unit 60 for recovering the substrate 1 (electrode 5) on which the electrode active material layer 4 has been formed. If the manufacturing apparatus 100a includes a recovery unit 70, the substrate transport unit 22 normally transports the substrate 1 supplied from the substrate supply unit 21 to the recovery unit 70.

[0020] In the manufacturing apparatus 100a, the supply unit 10 supplies granulated particles 2 containing electrode active material and binder. The conveying unit 20 conveys the granulated particles 2 supplied by the supply unit 10. The support unit 30 supports the granulated particles 2 conveyed by the conveying unit 20. The squeegee unit 40 is positioned on the support unit 30 with a gap between them and the granulated particles 2 to level the granulated particles 2 and form a granulated particle layer 3. In the manufacturing apparatus 100a, the support unit 30 and the squeegee unit 40 are each cylindrical (roll-shaped) and are positioned so that their axes of rotation are parallel to each other. In the manufacturing apparatus 100a, the support unit 30 and the squeegee unit 40 are rotated in the same direction, and the granulated particles 2 are passed through the gap between the support unit 30 and the squeegee unit 40, thereby leveling the granulated particles 2 and forming a granulated particle layer 3. The rolling unit 60 rolls the granulated particle layer 3 to form an electrode active material layer 4. In the manufacturing apparatus 100a, the rolling section 60 is a pair of rolling rolls 61 and 62, and the support section 30 also serves as one of the rolling rolls 61.

[0021] The manufacturing apparatus 100a further includes a pair of plate-shaped stock guide sections 50. Figure 2 is a schematic perspective view showing the support section 30, the squeegee section 40, and the pair of plate-shaped stock guide sections 50 in the manufacturing apparatus 100a; Figure 3 is a top view of the conveying section 20, the support section 30, the squeegee section 40, the pair of plate-shaped stock guide sections 50, and the rolling section 60 in the manufacturing apparatus 100a, viewed from the stock guide section 50 side; and Figure 4 is a schematic side view showing the conveying section 20, the support section 30, the squeegee section 40, and the pair of plate-shaped stock guide sections 50. In the manufacturing apparatus 100a, the pair of stock guide sections 50 are each independently arranged parallel to the side surface 40S of the squeegee section. Furthermore, as shown in Figure 4, the pair of stock guide sections 50 are arranged independently such that the upstream end 51 of the stock guide section 50 is located upstream of the gap t1 between the support section 30 and the squeegee section 40, and the downstream end 52 of the stock guide section 50 is located downstream of the gap t1. The pair of stock guide sections 50 are arranged such that the distance W between their sides corresponds to the width of the electrode active material layer. In Figure 4, the direction of transport of granulated particles is indicated by the arrow x.

[0022] Figure 5 is a schematic side view showing a modified example of the electrode active material layer manufacturing apparatus according to the first embodiment of the present invention, and Figure 6 is a schematic side view showing the transport section 20, support section 30, squeegee section 40, and stock guide section 50 of the manufacturing apparatus 100b shown in Figure 5. In the manufacturing apparatus 100b, an example is shown where the support section 30 is a plate-shaped support section 30.

[0023] [1.1.1. Supply section] The supply unit supplies granulated particles containing electrode active material and binder, and typically supplies a desired amount of granulated particles to the conveying unit. For example, a hopper can be used as such a supply unit. A hopper typically comprises a containment section for storing granulated particles, an inlet for introducing granulated particles into the containment section, and an outlet for discharging granulated particles from the containment section.

[0024] In a manufacturing apparatus, the supply unit is typically located upstream of the squeegee unit, in a position where granulated particles can be supplied to the conveying unit. For example, as shown in Figure 1, the supply unit can be positioned on the substrate conveying unit 22, which is located upstream of the squeegee unit 40.

[0025] Furthermore, the supply unit is positioned to supply granulated particles to any position in the width direction of the transport unit (a direction perpendicular to the transport direction of the granulated particles). In one embodiment, it is preferable to arrange the supply unit so as to be able to supply granulated particles to the central region in the width direction of the conveying unit. Specifically, it is preferable to arrange the discharge port of the supply unit in a range where the distance from the center of the conveying unit in the width direction is 40% of the total length of the conveying unit in the width direction, preferably 30% of the total length. As shown in Figures 1 and 3, if the conveying unit 20 is a base material conveying unit 22 containing a base material 1, it is preferable to arrange the discharge port of the supply unit in a range where the distance from the center of the base material is 40% of the total length of the base material in the width direction, preferably 30% of the total length in the width direction. In another embodiment, it is preferable that the supply unit is arranged so as to be able to supply granulated particles along the entire width of the conveying unit. As shown in Figures 1 and 3, if the conveying unit 20 is a substrate conveying unit 22 containing the substrate 1, it is preferable that the discharge port of the supply unit is arranged along the entire width of the substrate.

[0026] The distance from the surface of the conveying section to the discharge port of the supply section can be appropriately selected depending on the amount of granulated particles supplied, the width of the conveying section, and other factors.

[0027] The supply unit typically supplies granulated particles so that the basis weight of the electrode active material layer relative to the substrate is the desired amount.

[0028] [1.1.2. Conveying Section] The conveying section conveys the granulated particles supplied from the supply section. The conveying section conveys the granulated particles to the support section, squeegee section, and rolling section located downstream of the conveying section. In the manufacturing apparatus of the first embodiment, the conveying section conveys the granulated particles, thereby passing them through the gap provided between the support section and the squeegee section, which can level the granulated particles and form a granulated particle layer. In the manufacturing apparatus of the first embodiment, the conveying section conveys the granulated particle layer, and by passing the granulated particle layer through the rolling rolls 61 and 62 of the rolling section 60, the granulated particle layer can be rolled to form an electrode active material layer. As such a conveying section, for example, a base material conveying section 22 including the base material 1 can be used, as shown in Figure 1.

[0029] [1.1.3. Support part] The support section supports the granulated particles conveyed from the conveying section. The support section supports the granulated particles that spread in the planar direction of the support section when the granulated particles are leveled by the squeegee section, which will be described later. In the first embodiment, a part of the conveying section (substrate) is usually provided on the support section, and the support section supports the granulated particles via the conveying section (substrate).

[0030] The shape of the support portion is such that it can support the granulated particles, and can be, for example, a roll shape as shown in Figure 1 or a plate shape as shown in Figures 5 and 6. Among these, a roll shape for the support portion is preferred. This is because a roll shape for the support portion makes it easier to incorporate a part of the rolling portion, which will be described later, thus simplifying and saving space in the manufacturing equipment.

[0031] When the support portion is roll-shaped, the radius of the support portion can be appropriately selected to any diameter depending on the size of the electrode active material layer, etc., but for example it may be 50 mm or more, preferably 100 mm or more, and for example it may be 500 mm or less, preferably 400 mm or less.

[0032] [1.1.4. Squeegee Section] The squeegee portion is positioned on the support portion with a gap between it and the granulated particles to level them and form a granulated particle layer.

[0033] As shown in Figure 2, the squeegee portion 40 usually has a roll-like shape. The squeegee portion 40 is usually positioned with a predetermined gap from the surface of the support portion 30, and by passing the granulated particles through this gap, the granulated particles are leveled and a granulated particle layer is formed.

[0034] The size of the gap between the support portion and the squeegee portion can be adjusted as appropriate according to the desired thickness of the electrode active material layer. When the rolling portion has a pair of rolling rolls, the gap between the support portion and the squeegee portion is usually formed to be larger than the gap between the pair of rolling rolls.

[0035] Furthermore, if the support is roll-shaped, the squeegee and support are usually positioned so that their axes of rotation are parallel to each other. The rotation direction of the support and the rotation direction of the squeegee can be the same or opposite.

[0036] The radius of the squeegee portion can be appropriately selected depending on the shape of the support portion and the amount of granulated particles supplied, but for example it can be 20 mm or more, preferably 40 mm or more, and for example it can be 300 mm or less, preferably 250 mm or less.

[0037] The radius of the squeegee portion may be larger than, smaller than, or the same as the radius of the support portion.

[0038] [1.1.5. A pair of plate-shaped stock guide sections] The pair of plate-shaped stock guides are members that suppress the flow of granulated particles outside the desired area in the width direction of the support when the granulated particles are leveled by the support and squeegee. The pair of stock guides are usually placed on the support together with the squeegee.

[0039] The stock guide portion is plate-shaped, and is usually positioned so that the surface portion of the plate is parallel to the side surface of the squeegee portion, and the thickness portion of the plate is positioned opposite the support portion. The shape of the stock guide portion is preferably such that it can be positioned along the shape of the support portion. For example, as shown in Figures 1 to 4, when the support portion 30 is roll-shaped, the surface 50B (bottom surface) of the stock guide portion 50 that faces the support portion 30 is preferably curved. In this case, the ratio of the radius of curvature R1 of the curved surface of the stock guide portion to the radius of curvature R0 of the curved surface of the roll of the support portion (R1 / R0) is, for example, 0.95 or more, preferably 0.98 or more, and for example, 1.10 or less, preferably 1.05 or less. Ideally, R1 / R0 is 1.00, in which case the radius of curvature R0 of the curved surface of the roll of the support portion and the radius of curvature R1 of the curved surface of the stock guide portion are the same.

[0040] Furthermore, for example, as shown in Figures 5 and 6, if the support portion 30 is plate-shaped, it is preferable that the bottom surface of the stock guide portion 50 has a flat surface.

[0041] The pair of stock guide sections are each independently positioned parallel to the side surface of the squeegee section. Furthermore, the distance W between the side surfaces of the pair of stock guide sections corresponds to the width of the electrode active material layer. For example, as shown in Figure 3, if the axial length of the squeegee section 40 corresponds to the width of the electrode active material layer, the pair of stock guide sections 50 are positioned so that their opposing side surfaces are parallel to the side surface (end surface) of the squeegee section 40, and the squeegee section 40 is sandwiched between their side surfaces.

[0042] Each of the pair of stock guide sections is positioned independently such that the upstream end of the stock guide section is located upstream of the gap between the support section and the squeegee section, and the downstream end of the stock guide section is located downstream of the gap. In addition, typically, the sides of each of the pair of stock guide sections are positioned independently and continuously from the upstream end to the downstream end in the direction of granulation particle transport.

[0043] Here, the gap between the support and the squeegee refers to the narrowest gap between the support and the squeegee.

[0044] The statement that the upstream end of the stock guide portion is located upstream of the gap between the support portion and the squeegee portion means that at least the upstream end of the bottom of the stock guide portion is located upstream of the gap. The bottom of the stock guide portion refers to the portion corresponding to the bottom surface when the stock guide portion is viewed from the side, when the surface facing the support portion is considered the bottom surface (50B in Figure 2). The statement that the upstream end of the stock guide portion is located upstream of the gap can be confirmed by the fact that the upstream end 51 of the bottom 50B of the stock guide portion is located upstream of the gap t1, as shown in Figures 4 and 6.

[0045] Similarly, the statement that the downstream end of the stock guide portion is located downstream of the gap between the support portion and the squeegee portion means that at least the downstream end of the bottom of the stock guide portion is located downstream of the gap, which can be confirmed by the fact that the downstream end 52 of the bottom 50B of the stock guide portion is located downstream of the gap t1, as shown in Figures 4 and 6.

[0046] In the first embodiment, for example, it is preferable that the upstream end of each stock guide portion is located upstream of the upstream end of the squeegee portion, and the downstream end of the stock guide portion is located downstream of the downstream end of the squeegee portion, independently of each other. This is because it is possible to effectively suppress the decrease in edge smoothness and yield caused by the outward flow of granulated particles.

[0047] Here, the upstream end of the squeegee portion refers to the point of contact 41 between the tangent line L1, which passes through the center 30C of the support portion 30 and contacts the squeegee portion 40 on the upstream side, and the squeegee portion 40, when both the support portion 30 and the squeegee portion 40 are roll-shaped, as shown in Figure 4. Also, as shown in Figure 6, when the support portion 30 is plate-shaped and the squeegee portion 40 is roll-shaped, it refers to the point of contact 41 between the tangent line L1, which is perpendicular to the surface of the support portion 30 and contacts the squeegee portion on the upstream side, and the squeegee portion 40.

[0048] The statement that the upstream end of the stock guide section is located upstream of the upstream end of the squeegee section means that at least the upstream end of the bottom of the stock guide section is located upstream of the upstream end of the squeegee section. This can be confirmed by the fact that the upstream end 51 of the bottom 50B of the stock guide section is located upstream of the intersection point 43 between the tangent line L1 and the bottom of the stock guide section, as shown in Figures 4 and 6.

[0049] Similarly, the downstream end of the squeegee portion, as shown in Figure 4, refers to the point of contact 42 between the tangent line L2 that passes through the center 30C of the support portion 30 and contacts the squeegee portion 40 downstream, and the squeegee portion 40, when both the support portion 30 and the squeegee portion 40 are roll-shaped. Also, as shown in Figure 6, when the support portion 30 is plate-shaped and the squeegee portion 40 is roll-shaped, it refers to the point of contact 42 between the tangent line L2 that is perpendicular to the surface of the support portion 30 and contacts the squeegee portion downstream, and the squeegee portion 40.

[0050] The statement that the downstream end of the stock guide section is located downstream of the downstream end of the squeegee section means that at least the downstream end of the bottom of the stock guide section is located downstream of the downstream end of the squeegee section. This can be confirmed by the fact that, as shown in Figures 4 and 6, the end 52 of the bottom 50B of the stock guide section is located downstream of the intersection point 44 between the tangent line L2 and the bottom of the stock guide section.

[0051] The distance at which the upstream and downstream ends of the stock guide section are positioned from the gap between the support section and the squeegee section can be appropriately selected depending on the distance of the gap, as well as the shape, size, and positional relationship of the support section and the squeegee section. When the distance from the gap to the upstream end at the bottom of the stock guide section is D1, the ratio of distance D1 to the radius of the squeegee section may be, for example, 0.05 or more, 0.5 or more, 1.0 or more, or even greater than 1.0. Similarly, the ratio of distance D1 to the radius of the squeegee section may be, for example, 4.0 or less, 3.0 or less, or 2.0 or less. When the distance from the gap to the downstream end at the bottom of the stock guide section is D2, the ratio of distance D2 to the radius of the squeegee section may be, for example, 0.05 or more, 0.5 or more, 1.0 or more, or even greater than 1.0. Furthermore, the ratio of distance D2 to the radius of the squeegee portion can be, for example, 4.0 or less, 3.0 or less, or 2.0 or less. In Figures 4 and 6, distance D1 refers to the distance from the position of the gap t1 to the upstream end 51 of the bottom of the stock guide portion, and distance D2 refers to the distance from the position of the gap t1 to the downstream end 52 of the bottom of the stock guide portion.

[0052] As described above, in the manufacturing apparatus of the first embodiment, a portion of the conveying section is provided on the support section. In this case, the stock guide section and the conveying section may be in contact. The extent to which the stock guide section and the conveying section are in contact can be appropriately adjusted considering the damage to the conveying section caused by contact with the stock guide section. For example, if the support section is roll-shaped, the conveying section is provided along the roll of the support section, and the bottom surface of the stock guide section is a curved surface along the roll of the support section, the contact length of the stock guide section with respect to the circumference of the support section is preferably 7.5% or more, more preferably 7.7% or more, even more preferably 10% or more, preferably 17.5% or less, more preferably 17% or less, even more preferably 13.5% or less, and particularly preferably 13% or less.

[0053] The stock guide section preferably has low friction with the base material, which is the conveying section. Specifically, the coefficient of friction of the stock guide section is preferably 0.50 or less, more preferably 0.40 or less. Ideally, the coefficient of friction of the stock guide section is 0, and can be 0.04 or more as a lower limit. The coefficient of friction of the stock guide section refers to the static friction coefficient between the stock guide section and the base material, and can be measured in accordance with JIS K7125. Specifically, it can be measured by the method described in the examples.

[0054] Furthermore, the smaller the coefficient of friction of the stock guide portion, the less likely it is that the adhesion between the granulated particles and the stock guide portion will decrease. This can suppress the reduction in edge smoothness caused by granulated particles adhering to the stock guide portion.

[0055] Furthermore, in the manufacturing apparatus, as shown in Figure 6, the stock guide section and the support section may be arranged so that there is a gap g between them. In this case, the size of the gap g is adjusted to an extent that can suppress the outflow of granulated particles from the gap g. The size of the gap is usually 70% or less of the volume average particle diameter (D50) of the granulated particles, preferably 50% or less, usually 10% or more, and preferably 20% or more. By setting the size of the gap within the above range, the outflow of granulated particles from the gap can be suppressed, and damage to the conveying section can be suppressed.

[0056] The materials that make up the stock guide section are not particularly limited. Examples of materials for the stock guide section include polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene (ABS), polypropylene (PP), polystyrene (PS), polyethylene (PE), ultra-high molecular weight polyethylene, monomer casting nylon (UMC), polyvinyl chloride (PVC), polyacetal, and methacrylic resin.

[0057] The stock guide portion is a plate-shaped member, and its thickness may be such that it can hold granulated particles between the sides of a pair of stock guide portions. The thickness of the stock guide portion may be, for example, 10 mm or more and 30 mm or less.

[0058] The stock guide portion is positioned parallel to the side surface of the squeegee portion and in a position that does not obstruct the rotation of the squeegee portion. The stock guide portion may be positioned in contact with the side surface of the squeegee portion, as long as it does not obstruct the rotation of the squeegee portion. Figure 7(a) is a schematic side view showing one example of a method for fixing the stock guide portion. Figure 7(b) is a schematic side view showing another example of a method for fixing the stock guide portion. The stock guide portion 50 may be fixed together with the squeegee portion 40 to the fixing portion F1 of the squeegee portion 40, for example, as shown in Figure 7(a), or it may be fixed by providing a fixing portion F2 separate from the fixing portion F1 of the squeegee portion 40, as shown in Figure 7(b).

[0059] [1.1.6. Rolling Section] The rolling section rolls the granulated particle layer to form the electrode active material layer. The rolling section applies pressure perpendicular to the plane direction of the granulated particle layer to roll it and form the electrode active material layer. In the rolling section, the granulated particles are compressed, which can increase the adhesion between the granulated particles and the adhesion between the electrode active materials contained in the granulated particles. In addition, it can increase the adhesion of the constituent components of the entire layer and increase the strength of the electrode active material layer.

[0060] For example, a pair of rolling rolls can be used as the rolling section. If the support section described above is roll-shaped, the support section can be used as one of the pair of rolling rolls. When a pair of rolling rolls are used as the rolling section, the press pressure on the granulated particle layer can be adjusted by adjusting the gap between each rolling roll. For example, the press pressure can be adjusted by adjusting the difference between the size of the gap between the support section and the squeegee section and the size of the gap between each rolling roll. This also allows for adjustment of the density of the electrode active material layer. The distance between each rolling roll is usually adjusted to be narrower than the gap between the support section and the squeegee section. The specific distance can be adjusted as appropriate depending on the thickness and density of the electrode active material layer.

[0061] Examples of materials that make up the circumferential surfaces of the rolling rolls 61 and 62 include rubber, metal, and inorganic materials.

[0062] The rolling roll 62 may have a mechanism for heating its circumferential surface. This allows the granulated particle layer 3 to be rolled while being heated. By rolling the granulated particle layer 3 while heating it, the binder contained in the granulated particles 2 can be softened or melted, thereby binding the granulated particles 2 more firmly to each other.

[0063] [1.1.7. Any configuration] In addition to the above-described configuration, the method for manufacturing an electrode active material layer according to the present invention may include any other configuration as needed.

[0064] For example, an optional configuration may include a coating section located upstream of the supply section of the manufacturing apparatus, which applies a binder coating liquid onto the substrate. When the manufacturing apparatus includes a coating section, a binder coating liquid layer can be formed by applying the binder coating liquid to the substrate, and granulated particles can be supplied onto the binder coating liquid layer, thereby allowing the granulated particles to adhere closely to the substrate. Examples of coating sections that the manufacturing apparatus may include include a slot die head, a gravure head, a bar coat head, and a knife coat head.

[0065] Furthermore, the manufacturing apparatus may include a recovery section downstream of the rolling section for recovering the substrate on which the electrode active material layer has been formed. The recovery section could be, for example, a roll for winding the substrate.

[0066] [1.2. Method for manufacturing the electrode active material layer of the second embodiment] Figure 8 is a schematic side view showing an electrode active material layer manufacturing apparatus according to the second embodiment of the present invention. The electrode active material layer manufacturing apparatus 200 shown in Figure 8 comprises a supply unit 10, a support unit 30 which also serves as a transport unit 20, a squeegee unit 40 and a pair of plate-shaped stock guide units 50, and a rolling unit 60, in this order from upstream in the transport direction of granulated particles 2. The manufacturing apparatus 200 also includes a base material supply unit 91 located downstream of the squeegee unit 40 and upstream of the rolling unit 60, and a base material transport unit 92 which transports the base material 1 supplied from the base material supply unit 91 to the rolling unit 60. The manufacturing apparatus 200 may also optionally include a coating unit 80 between the base material supply unit 91 and the rolling unit 60 for coating the base material 1 with a binder coating liquid. Furthermore, the manufacturing apparatus 200 may optionally include a recovery unit 70 downstream of the rolling unit 60 for recovering the base material 1 (electrode 5) on which the electrode active material layer 4 has been formed.

[0067] In the manufacturing apparatus 200, the roll-shaped support section 30 also serves as the conveying section 20. By placing the supply section 10 on the support section 30, the granulated particles 2 are supplied so that they come into direct contact with the support section 30. The support section 30 rotates to convey the granulated particles 2 supplied from the supply section 10, and by passing the granulated particles 2 through the gap between the support section 30 and the squeegee section 40, the granulated particles 2 are leveled to form a granulated particle layer 3. The rolling section 60 rolls the granulated particle layer 3 formed on the support section 30 between the substrate 1 supplied from the substrate supply section 91 and the support section 30, and also functions as a transfer section that transfers the electrode active material layer 4 onto the substrate 1. Figure 8 shows an example in which the rolling section 60 is a pair of rolling rolls 61 and 62, and the support section 30 also serves as one of the rolling rolls 61.

[0068] In the second embodiment, the supply unit is typically positioned on a support unit located upstream of the squeegee unit. The supply unit is also positioned to supply granulated particles to any position in the width direction of the support unit. In particular, it is preferable that the supply unit be positioned to supply granulated particles to the central region in the width direction of the support unit. Specifically, it is preferable to position the discharge port of the supply unit within a distance of 40% of the total length of the support unit in the width direction from the center of the support unit in the width direction, preferably within a distance of 30% of the total length of the support unit in the width direction.

[0069] In the second embodiment, the support portion also serves as a conveying portion for transporting granulated particles, and since the granulated particles are transported on the surface of the support portion, it can be considered that the conveying portion is provided on the support portion. Such a support portion is preferably roll-shaped. In the second embodiment as well, the conveying portion and the stock guide portion may be in contact. In this case, the contact length and the coefficient of friction between the support portion (which is the conveying portion) and the stock guide portion can be the same as the range of the contact length and the coefficient of friction between the conveying portion and the stock guide portion in the first embodiment.

[0070] Furthermore, if a granulated particle layer is formed directly on the support section, the substrate can be supplied from a substrate supply section located downstream of the squeegee section and upstream of the rolling section, and the granulated particle layer formed on the support section can be rolled between the supplied substrate and the support section in the rolling section, thereby transferring the electrode active material layer onto the substrate. In this case, the rolling section also functions as a transfer section for transferring the electrode active material layer onto the substrate.

[0071] In the manufacturing apparatus 200, the contents may be the same as those described in the manufacturing apparatus for the electrode active material layer of the first embodiment, except for the points mentioned above.

[0072] [1.3. Variant Example] In addition to the manufacturing apparatus of the electrode active material layer according to the present invention, the following embodiments may also be used.

[0073] Figure 9 is a schematic side view showing a manufacturing apparatus for an electrode active material layer according to another embodiment of the present invention. The manufacturing apparatus 300 comprises a supply unit 10, a transport unit 20, a support unit 30, a squeegee unit 40 and a pair of plate-shaped stock guide units 50, and a rolling unit 60, in this order from upstream in the transport direction of the granulated particles 2. The manufacturing apparatus 300 comprises a substrate supply unit 23 that supplies a first substrate 1a upstream of the supply unit 10, and a first substrate transport unit 24 that transports the first substrate 1a from the supply unit 10 to a first substrate 1a recovery unit 25 located downstream of the rolling unit 60. The first substrate transport unit 24, which includes the first substrate 1a, also serves as the granulated particle transport unit 20. The apparatus also comprises a supply unit 93 for a second substrate 1b located downstream of the squeegee unit 40 and upstream of the rolling unit 60, and a second substrate transport unit 94 that transports the second substrate 1b to the rolling unit 60. In the manufacturing apparatus 300, the granulated particle layer 3 formed on the first substrate 1a is rolled between the first substrate 1a and the second substrate 1b in the rolling section 60 to form an electrode active material layer 4, which is then transferred onto the second substrate 1b, and the first substrate 1a is peeled off from the electrode active material layer 4.

[0074] In Figure 9, the manufacturing apparatus can be the same as described in the first and second embodiments, except that the substrate supply unit and substrate transport unit are located in two places: upstream of the supply unit and downstream of the squeegee unit.

[0075] [2. Method for manufacturing the electrode active material layer] The present invention relates to a method for manufacturing an electrode active material layer, which uses the manufacturing apparatus described in [1. Electrode Active Material Layer Manufacturing Apparatus] above, and comprises the steps of: (A) supplying granulated particles from a supply unit; (B) transporting the supplied granulated particles; (C) arranging the transported granulated particles on a support unit, leveling the granulated particles using a squeegee unit to form a granulated particle layer between the sides of a pair of stock guide units; and (D) rolling the granulated particle layer using a rolling unit to form an electrode active material layer.

[0076] In the manufacturing method of the present invention, arranging granulated particles on a support portion includes cases in which the granulated particles are arranged in direct contact with the support portion, and cases in which the granulated particles are arranged on the support portion via a substrate.

[0077] According to the present invention, by using the above-described manufacturing apparatus, an electrode active material layer with good edge smoothness can be manufactured with a high yield of granulated particles.

[0078] The method for manufacturing an electrode active material layer according to the present invention is not particularly limited as long as it includes steps (A) to (D) using the apparatus described above. However, it is preferable that the manufacturing method further includes a step of supplying a substrate before step (A), and that steps (A) to (D) are performed on the substrate, i.e., a manufacturing method using the electrode active material layer manufacturing apparatus of the first embodiment described above.

[0079] Furthermore, the method for manufacturing an electrode active material layer according to the present invention also preferably includes a step of supplying a substrate after step (C), and in step (D), a manufacturing method in which the electrode active material layer is transferred onto the substrate by rolling the granulated particle layer formed on the support portion between the supplied substrate and the support portion using a rolling section, that is, a manufacturing method using the electrode active material layer manufacturing apparatus of the second embodiment described above.

[0080] Therefore, the manufacturing method using the electrode active material layer manufacturing apparatus of the first embodiment described above will be described below as the manufacturing method of the third embodiment, and the manufacturing method using the electrode active material layer manufacturing apparatus of the second embodiment will be described below as the manufacturing method of the fourth embodiment.

[0081] [2.1. Method for manufacturing the electrode active material layer of the third embodiment] The third embodiment of the method for manufacturing an electrode active material layer further includes a step of supplying a substrate before step (A), and performing steps (A) to (D) on the substrate.

[0082] [2.1.1. Process (E): Base material supply process] Process (E) is a process that supplies the substrate before process (A), and specifically, it is a process that supplies the substrate from upstream of the supply section of the manufacturing equipment.

[0083] Typically, long-length substrates are supplied. Here, "long-length" refers to a shape having a length of five times or more its width, preferably 10 times or more, and specifically refers to a film shape having a length that allows it to be wound into a roll for storage or transport. There is no particular upper limit to the length; for example, it may be 10,000 times or less its width.

[0084] Examples of substrates include metal foils made of aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, and other alloys; films containing conductive materials (e.g., carbon, conductive polymers); paper; fabrics made of natural fibers, polymer fibers, etc.; and polymer resin films or sheets, which can be appropriately selected depending on the purpose. Examples of polymers that may be included in polymer resin films or sheets include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyimide, polypropylene, polyphenylene sulfide, polyvinyl chloride, aramid, PEN, PEEK, etc.

[0085] Among these, when manufacturing electrode sheets for lithium-ion battery electrodes, metal foil, carbon film, and conductive polymer film can preferably be used as the substrate, with metal foil being preferred. Of these, copper foil, aluminum foil, or aluminum alloy foil is preferred in terms of conductivity and voltage resistance. Furthermore, the surface of the substrate 1 may be subjected to treatments such as coating, drilling, buffing, sandblasting, and / or etching.

[0086] The thickness of the substrate is, for example, 1 μm or more, preferably 5 μm or more, and for example, 1000 μm or less, preferably 800 μm or less. The width of the substrate can be any width.

[0087] [2.1.2. Process (A): Supply of granulated particles] Step (A) is the step of supplying granulated particles from the supply unit. In the third embodiment, granulated particles are typically supplied from the supply unit onto the substrate.

[0088] Granulated particles typically contain an electrode active material and a binder, and may optionally contain other dispersants, conductive materials, and additives.

[0089] The electrode active material contained in the granulated particles may be either a positive electrode active material or a negative electrode active material. When granulated particles are used as electrode material for lithium-ion batteries, examples of positive electrode active materials include metal oxides that can be reversibly doped and dedoped with lithium ions. Examples of such metal oxides include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFeO4), and ternary active materials in which part of lithium cobalt oxide is replaced with nickel and manganese (e.g., LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 Examples include O2, etc. The positive electrode active materials exemplified above may be used individually or in combination depending on the application.

[0090] Examples of negative electrode active materials used as the counter electrode for lithium-ion batteries include low-crystallinity carbon (amorphous carbon) such as easily graphitizable carbon, poorly graphitizable carbon, and pyrolytic carbon; graphite (natural graphite, artificial graphite); alloy materials containing tin and silicon; oxides such as silicon oxide, tin oxide, and lithium titanate; and others. The electrode active materials exemplified above may be used individually or in combination as appropriate for the application.

[0091] For lithium-ion battery electrodes, the electrode active material is preferably granular and uniform in shape. If the particle shape is spherical, a higher density electrode can be formed during electrode molding.

[0092] The volume-average particle size (D50) of the electrode active material for lithium-ion battery electrodes is preferably 0.1 μm to 100 μm, more preferably 0.3 μm to 50 μm, and even more preferably 0.5 μm to 30 μm for both the positive electrode active material and the negative electrode active material.

[0093] Preferably, the binder included in the granulated particles is a compound that can bind the electrode active materials together. More preferably, the binder is a dispersible binder that disperses in a solvent. Examples of dispersible binders include polymer compounds such as silicone polymers, fluorine atom-containing polymers, conjugated diene polymers, acrylate polymers, polyimides, polyamides, and polyurethanes, with fluorine atom-containing polymers, conjugated diene polymers, and acrylate polymers being preferred, and more preferably conjugated diene polymers and acrylate polymers.

[0094] There are no particular restrictions on the shape of the dispersed binder, but it is preferable that it be particulate. Being particulate allows for good binding properties and reduces the decrease in capacity and degradation of the fabricated electrode due to repeated charging and discharging. Examples of particulate binders include aqueous dispersions of binder particles such as latex, and particulate binders obtained by drying such aqueous dispersions.

[0095] From the viewpoint of ensuring sufficient adhesion between the resulting electrode active material layer and the substrate, and lowering the internal resistance, the amount of binder is usually 0.1 parts by weight or more and 50 parts by weight or less, preferably 0.5 parts by weight or more and 20 parts by weight or less, and more preferably 1 part by weight or more and 15 parts by weight or less, based on dry weight, per 100 parts by weight of electrode active material.

[0096] As mentioned above, dispersants may be used with granulated particles as needed. Specific examples of dispersants include cellulosic polymers such as carboxymethylcellulose and methylcellulose, as well as their ammonium salts or alkali metal salts. These dispersants can be used individually or in combination of two or more.

[0097] As mentioned above, conductive materials may be used in the granulated particles as needed. Specific examples of conductive materials include conductive carbon blacks such as furnace black, acetylene black, and Ketjenblack (a registered trademark of AkzoNobel Chemicals Sloten Fennotschap). Among these, acetylene black and Ketjenblack are preferred. Other materials that can be used include vapor-grown carbon fibers such as VGCF® and carbon nanotubes; or graphite-based carbon materials such as expanded graphite and graphite; and graphene. These conductive materials can be used individually or in combination of two or more types.

[0098] Granulated particles are obtained by granulating an electrode active material, a binder, and other components such as the conductive material added as needed. The granulated particles consist of at least the electrode active material and the binder, but rather than each existing as an independent particle, two or more components, including the electrode active material and the binder, form a single particle. Specifically, multiple individual particles of the two or more components are bound together to form secondary particles, and it is preferable that multiple (preferably several to several dozen) electrode active materials are bound together by the binder to form a particle.

[0099] The method for producing granulated particles is not particularly limited and they can be produced by known granulation methods such as fluidized bed granulation, spray drying granulation, and rolling bed granulation.

[0100] The volume-average particle diameter (D50) of the granulated particles is typically 0.1 μm to 1000 μm, preferably 1 μm to 500 μm, and more preferably 30 μm to 250 μm, from the viewpoint of easily obtaining an electrode active material layer of the desired thickness.

[0101] The volume-average particle diameter (D50) of granulated particles is the 50% volume-average particle diameter calculated by dry measurement using a laser diffraction particle size distribution analyzer (e.g., Microtrac MT3300EX II; manufactured by Microtrac-Bell Co., Ltd.). The 50% volume-average particle diameter is the particle diameter at the point where the cumulative frequency, calculated from the smallest diameter side, reaches 50% in the obtained particle size distribution (volume-based).

[0102] The amount of granulated particles supplied from the supply unit can be adjusted as appropriate according to the size of the substrate and the desired basis weight.

[0103] [2.1.3. Process (B): Transportation process] Step (B) is a step for transporting the supplied granulated particles. In the third embodiment, the granulated particles are usually transported together with the substrate by a substrate transport unit, which acts as a transport unit.

[0104] [2.1.4. Process (C): Granulated particle layer formation process] Step (C) is a process in which the conveyed granulated particles are placed on the support section, the granulated particles are leveled using the squeegee section, and a granulated particle layer is formed between the sides of a pair of stock guide sections. In step (C), the granulated particles conveyed by the conveying section are leveled by passing them through the gap between the support section and the squeegee section, thereby forming a granulated particle layer with a predetermined thickness. Furthermore, in the manufacturing apparatus described above, a pair of plate-shaped stock guide sections are arranged parallel to the sides of the squeegee, so a granulated particle layer is formed between the sides of the pair of stock guide sections.

[0105] The gap between the support section and the squeegee section, and the distance between the sides of the pair of stock guide sections, can be appropriately selected according to the desired thickness and size of the electrode active material layer.

[0106] [2.1.5. Process (D): Rolling Process] Step (D) is a step (D) in which a granulated particle layer is rolled using a rolling section to form an electrode active material layer. For example, a pair of rolling rolls may be used as the rolling section. In step (D), the pressure on the granulated particle layer can be adjusted by adjusting, for example, the distance between the pair of rolling rolls.

[0107] When a pair of rolling rolls are used as the rolling section, the press pressure on the granulated particle layer can be adjusted by adjusting the distance between each rolling roll. For example, the density of the electrode active material layer can be adjusted by adjusting the difference between the gap between the support section and the squeegee section in process (C) and the distance between each rolling roll. The distance between each rolling roll is usually adjusted to be narrower than the gap between the support section and the squeegee section. The specific distance can be adjusted as appropriate depending on the thickness and density of the electrode active material layer.

[0108] The thickness of the electrode active material layer obtained by process (D) is not particularly limited.

[0109] [2.1.6. Process (F): Binding agent coating process] In the third embodiment, an optional step may be to apply a binder coating liquid containing a binder to the substrate surface before step (A). In this case, in step (A) described above, the granulated particles are supplied to the substrate surface to which the binder coating liquid has been applied.

[0110] The binder contained in the binder coating solution is preferably a compound capable of binding the powder containing the active material to the substrate. The binder coating solution may contain additives such as thickeners and surfactants to adjust the viscosity and wettability of the coating solution. Known thickeners and surfactants can be used. Examples of binders include SBR aqueous dispersions, acrylate polymer aqueous dispersions, polyacrylic acid (PAA) aqueous solutions, and polyvinylidene fluoride (PVDF) organic solvent solutions. In addition, a dispersion or solution containing a binder contained in granulated particles can also be used as the binder coating solution.

[0111] [2.2. Method for manufacturing the electrode active material layer of the fourth embodiment] The method for manufacturing the electrode active material layer of the fourth embodiment includes the steps (A) to (D) described above, and further includes the step of supplying a substrate after step (C), wherein step (D) includes transferring the electrode active material layer onto the substrate by rolling the granulated particle layer formed on the support portion between the supplied substrate and the support portion using the rolling portion.

[0112] The manufacturing method of the fourth embodiment may be the same as that described in the manufacturing method of the third embodiment described above, except that steps (A) to (C) are performed on a support, the step of supplying a substrate after step (C) is further included, and in step (D), the electrode active material layer is transferred onto the substrate by rolling the granulated particle layer formed on the support between the substrate and the support using a rolling unit.

[0113] In the manufacturing method of the fourth embodiment, an optional step may be included between the step of supplying a substrate and step (D), in which a binder coating liquid containing a binder is applied to the surface of the substrate.

[0114] [2.3. Variant Example] The method for manufacturing the electrode active material layer according to the present invention is not limited to the manufacturing methods of the third and fourth embodiments described above, but may also include, for example, a manufacturing method (manufacturing method of the sixth embodiment) in which steps (A) to (C) are performed on a first substrate as a transfer substrate using the manufacturing apparatus shown in Figure 9 (manufacturing apparatus of the fifth embodiment), and a step of supplying a second substrate after step (C) is further included, and in step (D), the electrode active material layer is transferred onto the second substrate by rolling the granulated particle layer formed on the first substrate between the first and second substrates using a rolling section.

[0115] [3. Electrode active material layer] The apparatus for manufacturing electrode active material layers and the manufacturing method using the same according to the present invention can be used to manufacture electrode active material layers for various batteries. In particular, it is preferable to use it for manufacturing electrode active material layers for lithium-ion batteries. Furthermore, if the substrate on which the electrode active material layer is formed is a conductive substrate, the substrate and the electrode active material layer can be obtained as electrodes (electrode sheets). [Examples]

[0116] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0117] In the following explanation, "%" and "parts" represent quantities based on mass unless otherwise specified. Furthermore, the operations described below were performed at room temperature (23°C) and atmospheric pressure (1 atm) unless otherwise specified.

[0118] [Evaluation Method] [Evaluation of electrode end strength] The strength (cutting strength) of the electrode active material layer of the fabricated electrodes was evaluated using the SAICAS method. In the SAICAS method, cutting was performed at an ultra-low speed using a sharp cutting blade from the surface of the sample (adherent) toward the adhesive interface with the substrate. At this time, the cutting strength was calculated from the horizontal force required to continuously separate the adherend from the substrate and the width of the cutting blade.

[0119] For measuring cutting strength, we used SAICAS (Surface And Interface Cutting Analysis System), DN-GS manufactured by Daipla Wintes Co., Ltd., and the test conditions were as follows. • Cutting edge: Borazon (width 500 μm) ·Horizontal speed: 2.0μm / sec • Measurement depth: 10 μm

[0120] For the positive electrode of Example 1, the measurement point was set at the center of the width direction perpendicular to the longitudinal direction (4000 μm from the edge), and the test was performed. Cutting strength was measured with N=3, and the results were evaluated using the following indicators A, B, and C. A: End strength 0.25N / mm or more B: End strength 0.15 N / mm or more and less than 0.25 N / mm C: End strength less than 0.15 N / mm

[0121] [Evaluation of foil wrinkles] The fabricated electrodes were visually inspected for wrinkles in the metal foil, and the number of wrinkles was determined. The results were evaluated using the following indicators. A: The metal foil is wrinkle-free (0 wrinkles) B: There are one or more but less than five wrinkles on the metal foil. C: There are five or more wrinkles on the metal foil.

[0122] [Evaluation of edge smoothness] For the fabricated electrodes, the width of the electrode active material layer was measured, and the edge smoothness was evaluated using the following index based on the amount of deviation from the target molding width. Generally, the smaller the amount of deviation, the better the edge smoothness. A: Target molding width within ±1.0mm B: Target molding width ±1.0mm to 2.0mm C: Target molding width ±2.0mm or more

[0123] [Yield Evaluation] The amount (weight) of granulated particles supplied and the weight of the positive electrode current collector were measured in advance. The weight of the prepared electrode was measured, and the weight of the electrode active material layer was determined by subtracting the weight of the positive electrode current collector from the weight of the electrode. The yield was calculated from the difference between the amount of granulated particles supplied and the weight of the electrode active material layer using the following formula. Yield [%] = 100 - {(Weight of supplied granulated particles - Weight of electrode active material layer) ÷ (Weight of supplied granulated particles) × 100} Yield was evaluated using the following indicators. A: Yield of 98% or more B: Yield of 96% or more but less than 98% C: Yield less than 96%

[0124] [Friction coefficient of the stock guide section] The static friction coefficients of the stock guide section and the positive electrode current collector were measured using the following procedure. The plate constituting the stock guide section and the positive electrode current collector were cut to a size of 80 mm x 200 mm to obtain test specimens. The test specimens were stacked together, and the coefficient of friction was measured using a friction measuring instrument (Toyo Seiki Seisakusho, "TR-2") in accordance with JIS K7125 (1999) with a 200 g load (travel distance: 100 mm, speed: 500 mm / min).

[0125] [Example 1] (Manufacturing of granulated particles) LiNi with an average particle size of 4.5 μm is used as the positive electrode active material. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 was prepared. Acetylene black (AB) was prepared as the conductive material. An acrylic binder was prepared as the binder, and carboxymethylcellulose (CMC) was prepared as the thickener. These materials were weighed out in weight ratios of positive electrode active material: conductive material: binder: thickener = 93.5:4:1.5:1.

[0126] Next, a conductive material and binder were added to a planetary disperser and mixed. Then, a positive electrode active material and deionized water as a solvent were added and mixed uniformly to prepare a solution for granulation powder formation. This prepared solution was then sprayed using a spray dryer manufactured by Okawara Chemical Machinery Co., Ltd., and the solvent was removed in droplet form. By drying, granulated particles with an average particle size of approximately 70 μm were obtained.

[0127] (Manufacturing of the positive electrode active material layer) Next, a binder coating solution was prepared by dispersing the same acrylic binder used for the granulated particles in water. The properties of this binder coating solution were a solid content concentration of 30% by mass, a viscosity of 6.7 mPa·s (25±2℃, 60 rpm), and a surface tension of 32 mN / m (Wilhelmy method). In addition, a long piece of aluminum foil with a thickness of 15 μm and a width of 250 mm was prepared as a positive electrode current collector and set in the electrode manufacturing line (manufacturing equipment) shown in Figure 1.

[0128] Strip-shaped current collector exposed portions are secured at both ends in the width direction of the positive electrode current collector, and the prepared binder coating liquid is applied in the middle region (central region in the width direction) between these current collector exposed portions at an application amount of about 0.003 mg / cm 2 using a gravure coater (coating section 80 in FIG. 1) so that the amount is achieved, thereby forming a binder coating liquid layer.

[0129] Then, in the central region in the width direction of the conveyed positive electrode current collector, the prepared granulated particles are supplied by a powder supply device (supply section) so that the basis weight (per side) is 28 mg / cm 2 The granulated particles supplied onto the positive electrode current collector are conveyed together with the positive electrode current collector to a downstream rolling roll (support section 30 in FIG. 1), and the unevenness in basis weight is eliminated by a roller squeegee (squeegee section 40 in FIG. 1), and the height in the vertical direction in the width direction of the positive electrode current collector is made uniform to obtain a substantially uniform thickness.

[0130] At this time, by providing stock guide sections (stock guide sections 50 in FIG. 1) on both side surfaces of the roller squeegee, the flow of the granulated particles in the width direction of the current collector was suppressed. For this stock guide section, the radius R (curvature radius R0) of the rolling roll as the support section and the curvature radius R1 of the bottom surface of the stock guide section are the same, the contact length between the current collector on the rolling roll and the current collector is 13.5% of the circumferential length of the rolling roll, the gap between the current collector on the rolling roll and the current collector is 0 mm, and the material of the stock guide section is polytetrafluoroethylene (PTFE). Also, the radius R of the rolling roll in the manufacturing apparatus was 125 mm, and the radius of the squeegee section was 50 mm. Also, the upstream end of the stock guide section was positioned upstream of the upstream end of the squeegee section, and the downstream end of the stock guide section was positioned downstream of the downstream end of the squeegee section, and the squeegee section and the stock guide section were arranged.

[0131] Next, a roll rolling is performed on the granulated particle layer by a further downstream rolling roll (rolling section 60 in FIG. 1) to form a positive electrode active material layer having a thickness of about 115 μm as the electrode active material layer. The pressing conditions were as follows.

[0132] Rolling roll spacing: 100 μm, linear pressure: 1 t / cm, and rolling temperature: 50°C

[0133] [Examples 2-4] The positive electrode active material layer was formed in the same manner as in Example 1, except that the stock guide portion used had a contact length with respect to the circumference of the rolling roll, which is the support portion, of 10.3% (Example 2), 7.5% (Example 3), and 17.5% (Example 4). The evaluation described above was then performed.

[0134] [Example 5] The positive electrode active material layer was formed in the same manner as in Example 1, except that the positive electrode current collector on the rolling roll, which serves as the support section, and the stock guide section were not in close contact, and a gap was provided between the stock guide section and the positive electrode current collector. The evaluation described above was then performed. The size of the gap was set to 50 μm. This is because the average particle size (D) of the granulated particles 50 This distance corresponds to 71% of (70 μm).

[0135] [Example 6] The positive electrode active material layer was formed in the same manner as in Example 1, except that ABS resin was used as the material for the stock guide portion and the friction coefficient of the stock guide portion was set to 0.38, and the above evaluation was performed.

[0136] [Example 7] The positive electrode active material layer was formed in the same manner as in Example 1, except that polycarbonate was used as the material for the stock guide portion and the friction coefficient of the stock guide portion was set to 0.50, and the above evaluation was performed.

[0137] [Comparative Example 1] The positive electrode active material layer was formed in the same manner as in Example 1, except that the stock guide section was not included, and the above evaluation was performed.

[0138] [Comparative Example 2] The positive electrode active material layer was formed in the same manner as in Example 1, except that a stock guide portion was used in which the upstream end of the stock guide portion was located upstream of the upstream end of the squeegee portion, and the downstream end of the stock guide portion was not located downstream of the gap portion, and the above evaluation was performed.

[0139] [Comparative Example 3] The positive electrode active material layer was formed in the same manner as in Example 1, except that a rotating body as shown in Patent Document 1 was placed instead of the stock guide section, and the above evaluation was performed. In Comparative Example 3, a pair of rotating bodies with the center of the disk as the axis of rotation were arranged so that their respective axes of rotation were parallel, and the shortest distance between the sides of each of the pair of rotating bodies was the set width. Furthermore, by rotating the pair of rotating bodies and passing the powder supplied to the substrate surface between the pair of rotating bodies, the powder supplied outside the set width of the substrate surface was moved into the set width of the substrate surface, while the basis weight of the granulated particles on the substrate surface was controlled by a squeegee member placed between the pair of rotating bodies.

[0140] The results are shown in Tables 1 and 2. In Tables 1 and 2, "contact length" refers to the length of the contact area between the stock guide and the positive electrode current collector on the rolling roll, relative to the circumference of the rolling roll, which is the support part. The gap with the support part refers to the value expressed as a ratio of the size of the gap between the positive electrode current collector on the rolling roll (which is the support part) and the stock guide part to the volume average particle diameter (D50) of the granulated particles.

[0141] [Table 1]

[0142] [Table 2]

[0143] In Examples 1 to 7, the upstream end of the stock guide section is located upstream of the gap between the support section and the squeegee section, and the downstream end of the stock guide section is located downstream of the gap between the support section and the squeegee section. In Examples 1 to 7, it was confirmed that the resulting positive electrode active material layer could have good edge smoothness and good edge strength. Furthermore, in Examples 1 to 7, an improvement in yield was confirmed compared to the case without a stock guide section, as shown in Comparative Example 1. On the other hand, as shown in Comparative Example 2, when the downstream end of the stock guide section was not positioned downstream of the gap, the edge smoothness was insufficient and the yield was low. As shown in Comparative Example 3, when a pair of rotating bodies were used instead of a pair of plate-shaped stock guide sections, it was confirmed that the edge smoothness was good, but the edge strength was insufficient. It was also confirmed that the yield was low. [Explanation of symbols]

[0144] 1 Base material 2 Granulated particles 3 Granulated particle layer 4 Electrode active material layer 5 electrodes 100a, 100b, 200, 300 Electrode Active Material Layer Manufacturing Equipment (Manufacturing Equipment) 10 Supply section 20 Conveying section 21, 91 Base material supply section 22, 92 Substrate transport section 30 Support part 40 Squeegee section 40S Squeegee side 41 Upstream end of the squeegee section 42 Downstream end of the squeegee section 50 A pair of plate-shaped stock guide sections 60 Rolling section 70 Recovery Section 80 Coating Section t1 gap

Claims

1. A supply unit that supplies granulated particles containing electrode active material and binder, A conveying unit that conveys the granulated particles supplied by the supply unit, A support section that supports the granulated particles conveyed by the conveying section, A squeegee portion is positioned on the support portion with a gap between it and the granulated particles to level the granulated particles and form a granulated particle layer, An apparatus for manufacturing an electrode active material layer, comprising: a rolling section for rolling the granulated particle layer to form an electrode active material layer, The apparatus for manufacturing the electrode active material layer has a pair of plate-shaped stock guide sections, The pair of stock guide sections are each independently positioned parallel to the side surface of the squeegee section, and The stock guide portion is positioned such that its upstream end is located upstream of the gap between the support portion and the squeegee portion, and its downstream end is located downstream of the gap. An apparatus for manufacturing an electrode active material layer, wherein the distance between the sides of the pair of stock guide sections is arranged to correspond to the width of the electrode active material layer.

2. The apparatus for manufacturing an electrode active material layer according to claim 1, wherein the support portion is roll-shaped, the pair of stock guide portions are arranged on the support portion, each of the pair of stock guide portions has a curved surface on the support portion side independently, and the ratio (R1 / R0) of the radius of curvature R1 of the curved surface of the stock guide portion to the radius of curvature R0 of the curved surface of the roll of the support portion is 0.95 or more and 1.10 or less.

3. The apparatus for manufacturing an electrode active material layer according to claim 2, wherein the transport section is provided on the support section, the transport section and the stock guide section are in contact, and the contact length of the stock guide section with respect to the circumference of the support section is 7.5% or more and 17.5% or less.

4. The apparatus for manufacturing an electrode active material layer according to claim 1, wherein the transport section is provided on the support section, and there is a gap between the transport section and the stock guide section, and the size of the gap is 70% or less of the average particle size (D50) of the granulated particles.

5. The apparatus for manufacturing an electrode active material layer according to claim 1, wherein each of the pair of stock guide sections independently has a coefficient of friction of 0.50 or less.

6. A method for manufacturing an electrode active material layer using the electrode active material layer manufacturing apparatus described in any one of claims 1 to 5, Step (A) of supplying the granulated particles from the supply unit, Step (B) for transporting the supplied granulated particles, Step (C) involves placing the conveyed granulated particles on a support section, leveling the granulated particles using the squeegee section, and forming the granulated particle layer between the sides of the pair of stock guide sections. The process (D) involves rolling the granulated particle layer using the rolling section to form the electrode active material layer, A method for producing an electrode active material layer, including the above.

7. The process further includes a step of supplying a substrate before the above step (A), The method for producing an electrode active material layer according to claim 6, wherein steps (A) to (D) are performed on the substrate.

8. Prior to step (A) above, a binder coating liquid containing a binder is applied to the surface of the substrate. The method for producing an electrode active material layer according to claim 7, wherein step (A) includes supplying the granulated particles to the substrate surface coated with the binder coating liquid.

9. The process further includes a step of supplying a substrate after the above step (C), The method for manufacturing an electrode active material layer according to claim 6, wherein step (D) includes transferring the electrode active material layer onto the substrate by rolling the granulated particle layer formed on the support portion between the supplied substrate and the support portion using the rolling portion.

Images