Coating device

Abstract

The disclosed coating device is provided with: a conveyance roller 110 that conveys a belt-like base material; and a die head 120 that faces the conveyance roller 110 with a gap G therebetween, and discharges and applies slurry from a discharge port 126 to the base material being conveyed. The conveyance roller 110 has a roller central region 110a which is the central region in the axial direction, and roller end regions 110b which are contiguous to both sides of the roller central region 110a. The discharge port 126 has a discharge central region 126a facing the roller central region 110a, and discharge end regions 126b facing the roller end regions 110b. End gaps Gb which represent gaps G between the roller end regions 110b and the discharge end regions 126b are wider than a central gap Ga which is a gap G between the roller central region 110a and the discharge central region 126a. Thus, a coating thickness of the slurry can be made uniform.

Description

Coating Equipment

[0001] The present disclosure relates to a coating device.

[0002] Conventionally, a coating device for applying a slurry to a belt-shaped substrate has been known (for example, see Patent Document 1). As shown in FIG. 1 of Patent Document 1, the coating device of Patent Document 1 includes a conveying roller that conveys the belt-shaped substrate, and a die head that faces the conveying roller across a gap and discharges a slurry from a discharge port onto the conveyed substrate to apply the slurry.

[0003] International Publication No. 2020 / 137349

[0004] Generally, the width of the gap between the conveying roller and the die head is constant over the entire axial length of the conveying roller. The inventors of the present application have discovered that when a slurry is applied to a substrate using a die head facing the conveying roller across such a constant gap, the thickness of the applied slurry tends to be small at both ends of the substrate in the width direction. Portions of the substrate with an excessively small applied thickness cannot be used for the intended purpose and are subject to disposal. In this situation, one of the objectives of the present disclosure is to uniformize the thickness of the applied slurry.

[0005] One aspect of the present disclosure relates to a coating device including a conveying roller that conveys a band-shaped substrate, and a die head that faces the conveying roller across a gap and discharges a slurry from a discharge opening onto the conveyed substrate, the conveying roller having a roller central region that is a region in the center of the conveying roller's axial direction and roller end regions that are continuous with both sides of the roller central region, the discharge opening having a discharge central region facing the roller central region and discharge end regions facing the roller end regions, and an end gap that is the gap between the roller end regions and the discharge end regions being wider than a center gap that is the gap between the roller central region and the discharge central region.

[0006] According to the present disclosure, the thickness of the applied slurry can be made uniform.

[0007] The novel features of the present invention are set forth in the appended claims, but the present invention, both in terms of structure and content, together with other objects and features of the present application, will be better understood from the following detailed description taken in conjunction with the drawings.

[0008] Fig. 1 is a cross-sectional view schematically showing an example of a coating device according to the present disclosure; Fig. 2 is a plan view conceptually showing the shapes of a conveying roller and a die head according to embodiment 1; Fig. 3 is a plan view conceptually showing the shapes of a conveying roller and a die head according to a modified example of embodiment 1; Fig. 4 is a plan view conceptually showing the shapes of a conveying roller and a die head according to embodiment 2; Fig. 5 is a plan view conceptually showing the shapes of a conveying roller and a die head according to embodiment 3;

[0009] An embodiment of a coating device according to the present disclosure will be described below using examples. However, the present disclosure is not limited to the examples described below. While specific numerical values ​​and materials may be used in the following description, other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained.

[0010] The coating device according to the present disclosure is a device for applying a slurry (e.g., an electrode mixture slurry) to a strip-shaped substrate (e.g., a current collector for a battery), and is a coating device generally referred to as a die coater. The type of slurry is not particularly limited, but when the slurry is an electrode mixture slurry, the coating device according to the present disclosure can also be referred to as a coating device for electrode mixture slurry. The coating device according to the present disclosure includes a conveying roller and a die head.

[0011] The transport roller, also referred to as a backup roller, transports a strip-shaped substrate. The substrate may be, for example, a metal foil (e.g., aluminum foil) used as an electrode current collector. The thickness of the substrate may be, for example, 5 μm or more and 30 μm or less. The transport roller may be a columnar or cylindrical roller. The rotation axis of the transport roller may extend perpendicular to the extension direction of the substrate. In other words, the rotation axis of the transport roller may extend parallel to the width direction of the substrate. The transport roller may rotate at a substantially constant rotational speed, in which case the substrate is transported at a substantially constant speed. The axial length of the transport roller may be, for example, 400 mm or more, 500 mm or more, 600 mm or more, 800 mm or more, or 1000 mm or more.

[0012] The conveying roller has a central region and end regions. The central region is the region in the center of the conveying roller in the axial direction. The end regions are regions that are continuous with both sides of the central region in the axial direction of the conveying roller. The length of the end regions in the axial direction of the conveying roller may be, for example, 1 mm or more and 30 mm or less, but is not limited to this.

[0013] The die head faces the conveying roller across a gap. The die head may face the conveying roller in a direction perpendicular to the axial direction of the conveying roller. The die head applies the slurry to the substrate conveyed by the conveying roller by discharging it from the discharge port. The die head may have a liquid reservoir where the slurry accumulates, and a liquid passage that connects the liquid reservoir with the discharge port and through which the slurry flows. The liquid reservoir, the liquid passage, and the discharge port may extend in the axial direction of the conveying roller.

[0014] The die head may have an inlet channel that opens to the outside and communicates with the liquid reservoir. Slurry may be supplied to the liquid reservoir from a slurry supply unit provided separately from the die head via this inlet channel. The slurry supplied to the liquid reservoir flows through the liquid passage and then can be discharged toward the substrate from the discharge port. The discharge port of the die head has a discharge central region and a discharge end region. The discharge central region is a region facing the roller central region of the conveying roller (across a gap). The discharge end region is a region facing the roller end region of the conveying roller (across a gap). The discharge end region may be a region continuous with both sides of the discharge central region in the axial direction of the conveying roller. The length of the discharge end region in the axial direction of the conveying roller may be, for example, 1 mm or more and 30 mm or less, but is not limited thereto.

[0015] The end gap, which is the gap between the roller end region and the discharge end region, is wider than the center gap, which is the gap between the roller center region and the discharge center region. The width of the center gap may be, for example, 100 μm or more and 200 μm or less. This makes it possible to make the coating thickness of the slurry uniform across the entire width of the substrate. In particular, it is possible to prevent the coating thickness of the slurry from becoming smaller at both ends of the width of the substrate.

[0016] The reason for this effect is believed to be as follows. Specifically, when the gap width is constant along the entire length, as in conventional coating devices, the slurry discharged from the die head's discharge port exerts pressure on the central region of the conveying roller, whereas in the end regions of the conveying roller, only pressure acts from the center toward the outside (axial end). As a result, the slurry escapes outward in the end regions, resulting in a smaller coating thickness at both ends of the substrate in the width direction. In contrast, in the coating device disclosed herein, the end gap is wider than the central gap, thereby reducing the discharge pressure in the end regions and preventing the slurry from escaping outward. Therefore, the slurry is sufficiently applied to the substrate even in the end regions, achieving a uniform coating thickness.

[0017] The end gap may widen as it moves away from the central gap. This configuration allows for a more uniform coating thickness of the slurry on the portion of the substrate corresponding to the end gap. The end gap may gradually widen in a linear manner, a curved manner, or a step-like manner as it moves away from the central gap. As an example of a step-like widening, a configuration in which the end gap widens only in one step at the boundary with the central gap (i.e., a configuration in which the width of the end gap is a constant width wider than the central gap) is not included in the configuration of this paragraph, but is included in the configurations up to the previous paragraph.

[0018] The widest portion of the end gap may be 2 μm or more and 100 μm or less wider than the center gap. This configuration allows for a more uniform coating thickness of the slurry. Specifically, if the widest portion of the end gap is less than 2 μm wider than the center gap, the effect of preventing the slurry from escaping to the outside at the end is limited. If the widest portion of the end gap is more than 100 μm wider than the center gap, there is a high risk that the gap between the die head and the substrate will be too wide, making it difficult to apply the slurry to the substrate. The widest portion of the end gap may be a portion of the end gap corresponding to the axial end of the end gap.

[0019] The length of the end gap in the axial direction of the conveying roller may be 1 mm or more and 30 mm or less. This configuration allows the thickness of the applied slurry to be made even more uniform. Specifically, when the length of the end gap in the axial direction of the conveying roller is 1 mm or more, the effect of efficiently suppressing the slurry from escaping to the outside can be obtained, while when the length is greater than 30 mm, the slurry is less likely to escape to the outside, and the effect is limited.

[0020] The discharge edge region may be formed so that it becomes more distant from the roller edge region as it moves away from the discharge central region. In this case, at least a portion of the discharge edge region may be formed linearly or curvedly. For example, it is conceivable that the entire discharge edge region is formed linearly, or that the entire discharge edge region is formed curvedly. Alternatively, it is conceivable that a portion of the discharge edge region is formed linearly, and the remaining portion of the discharge edge region is formed curvedly.

[0021] The roller end regions may be formed so that the distance from the roller central region increases with the distance from the discharge end region. In this case, at least a portion of the roller end regions may be formed linearly or curved in a longitudinal cross-sectional view (of the conveying roller). For example, the entire roller end region may be formed linearly, or the entire roller end region may be formed curvedly. Alternatively, a portion of the roller end region may be formed linearly, and the remaining portion of the roller end region may be formed curved.

[0022] The discharge end region may be formed so as to move away from the roller end region as it moves away from the discharge central region. The roller end region may be formed so as to move away from the discharge end region as it moves away from the roller central region. In other words, both the conveying roller and the discharge opening of the die head may be formed so that their end regions move away from each other as they move toward their axial ends. Even in this case, at least a portion of each end region may be formed in a linear or curved shape.

[0023] As described above, according to the present disclosure, by making the end gap wider than the center gap, it is possible to make the thickness of the applied slurry uniform, which further reduces the amount of substrate and slurry waste.

[0024] An example of a coating device according to the present disclosure will be described in detail below with reference to the drawings. The components described above can be applied to the components of the coating device of the example described below. The components of the coating device of the example described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiment. Of the components of the coating device of the example described below, components that are not essential to the coating device according to the present disclosure may be omitted. Note that the diagrams shown below are schematic and do not accurately reflect the shapes and number of actual components.

[0025] First Embodiment A first embodiment of the present disclosure will be described. As shown in FIG. 1 , a coating device 100 of this embodiment includes a conveying roller 110 and a die head 120.

[0026] The transport roller 110 transports a strip-shaped substrate B. The substrate B may be a current collector of a secondary battery. The transport roller 110 may be a columnar or cylindrical roller. The rotation axis of the transport roller 110 may extend perpendicular to the extension direction of the substrate B. The transport roller 110 may rotate at a substantially constant rotation speed.

[0027] The die head 120 faces the conveying roller 110 across a gap G, and applies a slurry (not shown) from a discharge port 126 to the conveyed substrate B. The slurry may be an electrode mixture slurry. The die head 120 has a first part 121 constituting its upper half, a second part 122 constituting its lower half, and a shim 127 sandwiched between the first part 121 and the second part 122.

[0028] The first component 121 is made of a metal material such as Invar. The first component 121 is formed in a slightly flat rectangular parallelepiped shape. The lower surface of the first component 121 is substantially flat. A first protrusion 121a whose vertical length decreases as it approaches the conveying roller 110 (lower left portion in FIG. 1 ) is formed on the first component 121. The tip of the first protrusion 121a may be coated with diamond-like carbon (DLC).

[0029] The second component 122 is made of a metal material such as Invar. The second component 122 is formed in a slightly flat rectangular parallelepiped shape. The upper surface of the second component 122 is substantially flat except for a liquid reservoir 124 (described later). A second protrusion 122a, whose vertical length decreases as it approaches the conveying roller 110, is formed in a portion of the second component 122 facing the conveying roller 110 (the upper left portion in FIG. 1 ). The tip of the second protrusion 122a may be coated with DLC.

[0030] A recess is formed in the upper portion of the second part 122 as a liquid reservoir 124. The liquid reservoir 124 extends over substantially the entire longitudinal direction of the second part 122. An inlet channel 123 is formed in the longitudinal center of the second part 122, communicating with the liquid reservoir 124 from the outside. Slurry may be supplied to the inlet channel 123 from an external slurry supply unit (not shown).

[0031] A liquid passage 125 is formed between the first part 121 and the second part 122 in a region closer to the conveying roller 110 (to the left in FIG. 1 ) than the liquid reservoir 124. The liquid passage 125 is a passage through which the slurry flows. Both longitudinal ends of the liquid passage 125 are closed by shims 127. The outlet of the liquid passage 125 facing the conveying roller 110 is a discharge port 126. The slurry supplied to the die head 120 flows through the inlet channel 123, the liquid reservoir 124, the liquid passage 125, and the discharge port 126 in this order, and is then applied to the surface of the substrate B being conveyed by the conveying roller 110.

[0032] The shim 127 is a plate-shaped member also known as an inner deckle. The shim 127 is sandwiched between the first component 121 and the second component 122. The thickness of the shim 127 is substantially equal to the flow path width of the liquid passage 125. The longitudinal length of the shim 127 is substantially equal to the longitudinal length of the die head 120. The shim 127 has openings corresponding to the liquid passage 125 and the discharge port 126. The shim 127 closes both longitudinal ends of the liquid passage 125.

[0033] As shown in Fig. 2, the conveying roller 110 has a roller central region 110a, which is the region in the center in the axial direction, and roller end regions 110b, which are continuous with both sides of the roller central region 110a (both left and right in Fig. 2). The roller central region 110a and the roller end regions 110b are linearly connected throughout. In other words, the roller central region 110a and the roller end regions 110b extend in the axial direction of the conveying roller 110.

[0034] The discharge port 126 of the die head 120 has a discharge central region 126a facing the roller central region 110a and a discharge end region 126b facing the roller end region 110b. The discharge central region 126a extends parallel to the roller central region 110a. The discharge end region 126b is formed so as to become farther away from the roller end region 110b as it moves away from the discharge central region 126a. In this embodiment, the discharge end region 126b is formed linearly throughout, but this is not limited to this. For example, a portion of the discharge end region 126b may be formed linearly, and the remaining portion of the discharge end region 126b may be formed curved.

[0035] 2 shows only the region of the die head 120 corresponding to the discharge port 126. In other words, non-opening portions (regions closed by shims 127) located on both sides of the discharge port 126 of the die head 120 are omitted in FIG. 2. In addition, in FIG. 2, the boundaries between the central regions 110a, 126a and the end regions 110b, 126b are indicated by dashed lines.

[0036] As can be seen from the shapes of each part described above, the end gap Gb, which is the gap G between the roller end region 110b and the discharge end region 126b, is wider than the center gap Ga, which is the gap G between the roller center region 110a and the discharge center region 126a. Preferably, the end gap Gb widens as it moves away from the center gap Ga. Preferably, the widest portion of the end gap Gb (in this example, the axial end) is wider than the center gap Ga by 2 μm or more and 100 μm or less. Preferably, the length of the end gap Gb in the axial direction of the conveying roller 110 is 1 mm or more and 30 mm or less.

[0037] Modification of First Embodiment A modification of the first embodiment of the present disclosure will be described. The coating device 100 of this modification differs from the first embodiment in the shape of the discharge port 126 of the die head 120. The following mainly describes the differences from the first embodiment.

[0038] 3, the discharge end region 126b of this modification is formed in a curved shape throughout. More specifically, the discharge end region 126b is formed in a curved shape that is convex outward. However, the discharge end region 126b may also be formed in a curved shape that is convex inward.

[0039] Second Embodiment A second embodiment of the present disclosure will be described. The coating device 100 of this embodiment differs from the first embodiment in the shapes of the transport roller 110 and the die head 120. The following mainly describes the differences from the first embodiment.

[0040] As shown in Figure 4, the conveying roller 110 of this embodiment is formed so that the roller end region 110b becomes farther from the discharge end region 126b as it moves away from the roller central region 110a. Here, the roller central region 110a extends in the axial direction of the conveying roller 110, and the roller end region 110b extends obliquely with respect to the axial direction. The roller end region 110b is formed linearly throughout in a vertical cross section. However, at least a portion of the roller end region 110b may be formed curved in a vertical cross section.

[0041] In the present embodiment, the discharge port 126 of the die head 120 has a central discharge region 126 a and a peripheral discharge region 126 b that are linearly connected over the entire length of the discharge port 126. In other words, the discharge port 126 extends parallel to the central roller region 110 a (or in the longitudinal direction of the die head 120) over the entire length of the discharge port 126.

[0042] Third Embodiment A third embodiment of the present disclosure will be described. The coating device 100 of this embodiment differs from the first embodiment in the shapes of the transport roller 110 and the die head 120. The following mainly describes the differences from the first embodiment.

[0043] 5, the conveying roller 110 of this embodiment is formed such that the roller end region 110b becomes farther from the discharge end region 126b as it moves away from the roller central region 110a. Here, the roller central region 110a extends in the axial direction of the conveying roller 110, and the roller end region 110b extends obliquely relative to the axial direction. The roller end region 110b is formed linearly throughout in a vertical cross section. However, at least a portion of the roller end region 110b may be formed curved in a vertical cross section.

[0044] In the die head 120 of this embodiment, the discharge end region 126b is formed in a curved shape throughout. More specifically, the discharge end region 126b is formed in a curved shape that is convex outward. However, the discharge end region 126b may also be formed in a curved shape that is convex inward.

[0045] <<Supplementary Notes>> The above embodiments disclose the following technologies. (Technology 1) A coating device comprising: a conveying roller for conveying a band-shaped substrate; and a die head facing the conveying roller across a gap and discharging slurry from a discharge opening to coat the conveyed substrate, wherein the conveying roller has a roller central region that is a region in the center of the axial direction of the conveying roller, and roller end regions continuous with both sides of the roller central region, and the discharge opening has a discharge central region facing the roller central region and a discharge end region facing the roller end region, and the end gap between the roller end region and the discharge end region is wider than the center gap between the roller central region and the discharge central region. (Technology 2) A coating device according to Technology 1, wherein the end gap widens with increasing distance from the center gap. (Technology 3) A coating device according to Technology 1 or 2, wherein the widest portion of the end gap is wider than the center gap by 2 μm or more and 100 μm or less. (Technology 4) A coating device according to any one of Technologies 1 to 3, wherein the length of the end gap in the axial direction of the conveying roller is 1 mm or more and 30 mm or less. (Technology 5) A coating device according to any one of Technologies 1 to 4, wherein the discharge end region is formed so as to become more distant from the roller end region as it becomes more distant from the discharge central region. (Technology 6) A coating device according to Technology 5, wherein at least a part of the discharge end region is formed linearly. (Technology 7) A coating device according to Technology 5 or 6, wherein at least a part of the discharge end region is formed curvedly. (Technology 8) A coating device according to any one of Technologies 1 to 7, wherein the roller end region is formed so as to become more distant from the discharge end region as it becomes more distant from the roller central region. (Technology 9) A coating device according to Technology 8, wherein at least a part of the roller end region is formed linearly in a vertical cross section. (Technology 10) A coating device according to Technology 8 or 9, wherein at least a part of the discharge end region is formed curvedly in a vertical cross section.(Technology 11) The coating device according to any one of Technologies 1 to 10, wherein the discharge end region is formed so as to become farther away from the roller end region as it becomes farther away from the discharge central region, and the roller end region is formed so as to become farther away from the discharge end region as it becomes farther away from the roller central region.

[0046] The coating thickness uniformity of the slurry was evaluated for the coating devices of Examples 1 to 9 and Comparative Examples 1 and 2 shown below. The uniformity of the slurry coating thickness was evaluated by the ratio T1 / T2 (unit: %) of the coating thickness T1 near the end (specifically, the coating thickness T1 at a point 10 mm inward from the axial end of the transport roll) to the coating thickness T2 near the center (specifically, the average coating thickness T2 in a region 100 to 200 mm from the axial end of the transport roll). For example, if T1 is 80 μm and T2 is 100 μm, the ratio T1 / T2 is 80%. The closer T1 / T2 is to 100%, the higher the uniformity of the slurry coating thickness can be evaluated.

[0047] Example 1 A coating device of the type described in the first embodiment was prepared. In this coating device, both the central and end regions of the conveying roll were straight. Meanwhile, the die head had a straight discharge central region, while the end regions of the conveying roll were linearly spaced apart from the end regions as they moved away from the central region. The axial length of the conveying roller was 600 mm. The width of the central gap was 150 μm. The widest portion of the end gap was 2 μm wider than the central gap. The length of the end gap in the axial direction of the conveying roller was 20 mm. Using this coating device, an electrode mixture slurry (slurry) was applied to a current collector (substrate). The ratio T1 / T2 was 96.1%.

[0048] Example 2 An electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 1, except that the widest portion of the end gap was made 20 μm wider than the center gap. The ratio T1 / T2 was 97.8%.

[0049] Example 3 An electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 1, except that the widest portion of the end gap was made 50 μm wider than the center gap. The ratio T1 / T2 was 98.2%.

[0050] Example 4 An electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 1, except that the widest portion of the end gap was made 100 μm wider than the center gap. The ratio T1 / T2 was 97.3%.

[0051] Example 5 An electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 1, except that the widest portion of the end gap was made 120 μm wider than the center gap. The ratio T1 / T2 was 95.1%.

[0052] Example 6 An electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 1, except that the widest portion of the end gap was wider than the center gap by 50 μm and the length of the end gap in the axial direction of the conveying roller was 1 mm. The ratio T1 / T2 was 95.3%.

[0053] Example 7 The electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 6, except that the length of the end gap in the axial direction of the conveying roller was 10 mm. The ratio T1 / T2 was 97.9%.

[0054] Example 8 The electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 6, except that the length of the end gap in the axial direction of the conveying roller was set to 30 mm. The ratio T1 / T2 was 96.6%.

[0055] Example 9 The electrode mixture slurry (slurry) was applied to a current collector (substrate) using the same coating device as in Example 6, except that the length of the end gap in the axial direction of the conveying roller was 40 mm. The ratio T1 / T2 was 94.1%.

[0056] Comparative Example 1 In the coating device of Comparative Example 1, the conveying roll had a straight shape in both the roll central region and the roll end region. Meanwhile, the die head had a straight shape in the discharge central region, while the discharge end region had a shape that approached a linear shape from the roller end region as it moved away from the discharge central region. The axial length of the conveying roller was 600 mm. The width of the central gap was 150 μm. The narrowest portion of the end gap was 10 μm narrower than the central gap. The length of the end gap in the axial direction of the conveying roller was 20 mm. Using this coating device, an electrode mixture slurry (slurry) was applied to a current collector (substrate). The ratio T1 / T2 was 90.2%.

[0057] Comparative Example 2 In the coating device of Comparative Example 2, the conveying roll had a straight shape in both the roll central region and the roll end region. Furthermore, the die head had a straight shape in both the discharge central region and the discharge end region. That is, in the coating device of Comparative Example 2, the gap width in the axial direction of the conveying roll was constant at 150 μm throughout. The axial length of the conveying roller was 600 mm. Using this coating device, the electrode mixture slurry (slurry) was applied to a current collector (substrate). The ratio T1 / T2 was 92.7%.

[0058] As described above, the coating devices of Examples 1 to 9 had higher uniformity in the coating thickness of the slurry (or the value of the ratio T1 / T2) than the coating devices of Comparative Examples 1 and 2. Therefore, it can be said that the superiority of each Example was demonstrated.

[0059] While the present invention has been described in terms of presently preferred embodiments, such disclosure is not to be interpreted as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. It is therefore intended that the appended claims be interpreted to cover all changes and modifications that do not depart from the true spirit and scope of the invention.

[0060] The present disclosure can be used in coating devices.

[0061] 100: Coating device 110: Conveying roller 110a: Roller central region 110b: Roller end region 120: Die head 121: First part 121a: First protrusion 122: Second part 122a: Second protrusion 123: Inlet channel 124: Liquid reservoir 125: Liquid passage 126: Discharge outlet 126a: Discharge central region 126b: Discharge end region 127: Shim B: Substrate G: Gap Ga: Central gap Gb: End gap

Claims

1. A coating device comprising: a conveying roller for conveying a band-shaped substrate; and a die head opposed to the conveying roller across a gap, which dispenses slurry from an outlet to coat the substrate being conveyed, wherein the conveying roller has a roller central region which is a region in the center of the roller in the axial direction, and roller end regions continuous with either side of the roller central region, and the outlet has an outlet central region which faces the roller central region, and an outlet end region which faces the roller end region, and an end gap which is the gap between the roller end region and the outlet end region is wider than a central gap which is the gap between the roller central region and the roller central region.

2. The coating apparatus of claim 1, wherein the end gaps widen away from the central gap.

3. A coating device as claimed in claim 1 or 2, wherein the widest portion of said end gap is at least 2 µm and not more than 100 µm wider than said central gap.

4. A coating device according to claim 1 or 2, wherein the length of the end gap in the axial direction of the conveying roller is 1 mm or more and 30 mm or less.

5. A coating device according to claim 1 or 2, wherein the discharge end region is formed so as to become more distant from the roller end region as it moves away from the discharge central region.

6. The coating device according to claim 5, wherein at least a portion of the discharge end region is formed in a straight line.

7. The coating device according to claim 5, wherein at least a portion of the discharge end region is curved.

8. A coating device according to claim 1 or 2, wherein the roller end regions are formed so as to become more distant from the discharge end region as they move away from the roller central region.

9. The coating device according to claim 8, wherein at least a portion of the roller end region is formed straight in a vertical cross-sectional view.

10. The coating device according to claim 8, wherein at least a portion of the discharge end region is formed in a curved shape when viewed in vertical cross section.

11. A coating device as described in claim 1 or 2, wherein the discharge end region is formed so as to move away from the roller end region as it moves away from the discharge central region, and the roller end region is formed so as to move away from the discharge end region as it moves away from the roller central region.

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