Manufacturing method for electrode body

Abstract

To provide a manufacturing method for an electrode body capable of achieving uniform thickness in a narrow protective layer when forming a protective layer adjacent to the side edge of an active material layer by spray coating.SOLUTION: A manufacturing method for an electrode body 10 includes a protective layer coating step S3 in which a protective layer 3 adjacent to a side edge 2S of an active material layer 2 is coated onto an electrode foil 1 with a predetermined width w. The protective layer coating step includes a coating liquid shielding mechanism 4K, which positions a shielding member 4, having an aperture 41 opened to a predetermined width of the protective layer, at a position spaced upwardly from the electrode foil. A protective layer coating liquid 31 is ejected radially onto the electrode foil from a spray nozzle 5 positioned centrally above the width direction of the aperture.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] For example, in order to prevent internal short circuits, a narrow protective layer is formed adjacent to the side edge of the positive electrode active material layer on the positive electrode plate of an electrode body of a lithium ion secondary battery (see Patent Document 1). The protective layer can be formed, for example, by spraying a coating liquid, which is prepared by dissolving insulating ceramic particles and a binder, etc. in a solvent, onto the uncoated portion of the positive electrode foil and then drying the coating liquid together with the active material layer.

[0003] However, when spraying the coating liquid, the fine particles of the coating liquid ejected radially from the spray nozzle tend to diffuse to the periphery, which creates a problem in that the thickness of the protective layer tends to be uneven between the center of the nozzle and the periphery of the nozzle.

[0004] To address such problems in spray coating, for example, Patent Document 2 discloses a method of preventing fine particles of the coating liquid from diffusing to the surrounding area by blowing air onto the periphery of the nozzle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-116966 [Patent Document 2] Japanese Patent Publication No. 2022-116582 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even with the method disclosed in Patent Document 2, when a protective layer is narrow, the air blown around the nozzle may blow away fine particles of the coating liquid in the center of the nozzle, which may exacerbate unevenness in the thickness of the protective layer.

[0007] The disclosed technology has been made in consideration of such problems, and aims to provide a method for manufacturing an electrode body that can make the thickness of a narrow protective layer uniform when forming the protective layer adjacent to the side edge of the active material layer by spray coating. [Means for solving the problem]

[0008] (1) One aspect of the disclosed technology for solving the above-described problems is a method for manufacturing an electrode body, which includes a protective layer coating step of coating an electrode foil with a protective layer of a predetermined width adjacent to a side edge portion of an active material layer, wherein the protective layer coating step includes a coating liquid shielding mechanism that arranges a shielding member having an opening with the predetermined width of the protective layer at a position spaced above the electrode foil, and the coating liquid for the protective layer is sprayed onto the electrode foil from a spray nozzle that is arranged above the center of the opening in the width direction.

[0009] (2) In the manufacturing method of the electrode body described in (1), it is preferable that the coating liquid shielding mechanism includes a drive unit that rotates the shielding member and moves the coating liquid attached to the shielding member in a direction away from the opening.

[0010] (3) In the method for manufacturing an electrode body described in (1) or (2), it is preferable that the coating liquid shielding mechanism is equipped with a coating liquid recovery and reuse system that recovers and reuses the coating liquid shielded by the shielding member. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a system schematic diagram showing the overall configuration of a manufacturing apparatus used in a method for manufacturing an electrode body according to one aspect of the present embodiment. [Figure 2]FIG. 2 is a flowchart showing a method for manufacturing an electrode body using the manufacturing apparatus shown in FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view of part A shown in FIG. [Figure 4] FIG. 2 is an enlarged cross-sectional view of a first modified example of a portion A shown in FIG. [Figure 5] FIG. 2 is an enlarged cross-sectional view of a modified example 2 of the part A shown in FIG. [Figure 6] FIG. 2 is an enlarged cross-sectional view of a third modified example of the part A shown in FIG. [Figure 7] FIG. 2 is an enlarged cross-sectional view of a fourth modified example of the portion A shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Description of the manufacturing method and manufacturing device of the electrode body> Next, a method and an apparatus for manufacturing an electrode assembly according to one aspect of an embodiment of the disclosed technology will be described in detail with reference to the drawings. FIG. 1 shows a system schematic diagram illustrating the overall configuration of a manufacturing apparatus used in a method for manufacturing an electrode assembly according to one aspect of this embodiment. FIG. 2 shows a flowchart illustrating a method for manufacturing an electrode assembly using the manufacturing apparatus shown in FIG. 1. FIG. 3 shows an enlarged cross-sectional view of portion A shown in FIG. 1. The X direction indicates the longitudinal direction (transport direction) of the electrode assembly in this manufacturing method, the Y direction indicates the up-down direction of the electrode assembly in this manufacturing method, and the Z direction indicates the lateral direction (width direction) of the electrode assembly in this manufacturing method.

[0013] As shown in Figures 1, 2, and 3, the manufacturing method of this electrode body 10 includes an electrode foil rewinding process S1 in which an electrode foil 1 wound in a coil shape is rewound into a strip shape on an unwinding device 81; an active material layer coating process S2 in which a coating liquid 21 that forms an active material layer 2 is applied to the rewound electrode foil 1; a protective layer coating process S3 in which a coating liquid 31 that forms a protective layer 3 is applied to the same electrode foil 1 at a position adjacent to a side edge portion 2S of the active material layer 2; a drying process S4 in which the active material layer 2 and protective layer 3 applied to the electrode foil 1 are dried in a drying booth 7; and an electrode body winding process S5 in which the electrode body 10 with the dried active material layer 2 and protective layer 3 is wound up on a winding device 82.

[0014] Furthermore, the electrode body 10 wound around the winding device 82 in the electrode body winding step S5 is loaded onto the unwinding device 81, and the following steps are performed: an electrode foil unwinding step S1; an active material layer coating step S2 in which a coating liquid 21 constituting the active material layer 2 is applied to the back surface of the rewound electrode foil 1; a protective layer coating step S3 in which a coating liquid 31 constituting the protective layer 3 is applied to the back surface of the same electrode foil 1 at a position adjacent to the side edge portion 2S of the active material layer 2; a drying step S4 in which the active material layer 2 and protective layer 3 applied to the back surface of the electrode foil 1 are dried in a drying booth 7; and an electrode body winding step S5 in which the electrode body 10 with the dried active material layer 2 and protective layer 3 is wound around the winding device 82, thereby forming the active material layer 2 and the protective layer 3 on both sides of the electrode foil 1. Note that the protective layer coating step S3 may involve applying the coating liquid 31 constituting the protective layer 3 to a position adjacent to the side edge portion 2S on both sides in the width direction (Z direction) of the active material layer 2. In this case, after the drying step S4, a dividing step (not shown) is performed in which the active material layer 2 is divided into two equal parts at the center in the width direction, and then the electrode body winding step S5 is performed.

[0015] The manufacturing apparatus 100 used in the manufacturing method of the electrode body 10 also includes a conveying device 8 for the electrode foil 1 including a plurality of auxiliary rollers 83 that guide the movement of the electrode foil 1 between the unwinding device 81 and the winding device 82, a spray nozzle 5 used in the protective layer coating process S3, a coating liquid recovery and reuse system 6 that recovers and reuses the coating liquid 31 of the protective layer 3 that has been shielded by the shielding member 4, a die coater 9 used in the active material layer coating process S2, a coating liquid supply system 91 that supplies the coating liquid 21 to the die coater 9, and a drying booth 7 that dries the active material layer 2 and protective layer 3 that have been coated on the electrode foil 1.

[0016] Here, the protective layer coating step S3 is performed after the active material layer coating step S2, but this is not necessarily limited to this, and for example, the protective layer coating step S3 may be performed before the active material layer coating step S2. Furthermore, in the active material layer coating step S2, the coating liquid 21 supplied by the coating liquid supply system 91 for the active material layer 2 is applied to the electrode foil 1 by the die coater 9, but this is not necessarily limited to this, and for example, the coating liquid 21 may be applied by a spray nozzle.

[0017] The following provides a more detailed description of the manufacturing method for the electrode body 10. Details of the coating liquid recovery and reuse system 6 that recovers and reuses the coating liquid 31 of the protective layer 3 will be described later.

[0018] The manufacturing method of the electrode assembly 10 includes a protective layer coating step S3 in which a protective layer 3 is coated on the electrode foil 1 at a predetermined width w adjacent to the side edge portion 2S of the active material layer 2. The protective layer coating step S3 includes a coating liquid shielding mechanism 4K, as shown in FIG. 3 , which is positioned above the electrode foil 1 and includes a shielding member 4 having an opening 41 that opens at the predetermined width w of the protective layer 3. Preferably, the coating liquid 31 for the protective layer 3 is radially sprayed onto the electrode foil 1 from a spray nozzle 5 positioned above the center of the opening 41 in the width direction. In this case, among the fine particles of the coating liquid 31 radially sprayed from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 that are distributed with a relatively uniform density in the center of the nozzle pass through the opening 41 of the shielding member 4 and are coated onto the electrode foil 1 at the predetermined width w of the protective layer 3. Therefore, even if the predetermined width w of the protective layer 3 is narrow, the thickness t of the protective layer 3 can be made uniform.

[0019] The electrode body 10 may be either a positive electrode body or a negative electrode body, but here, the positive electrode body of a lithium ion secondary battery will be described as an example. The electrode foil 1 of this positive electrode body is a metal foil extending in a strip shape in the longitudinal direction (X direction), and is preferably made of aluminum or an aluminum alloy. The thickness of the electrode foil 1 is, for example, about 5 μm to 20 μm. The active material layer 2 is made of, for example, a lithium transition metal oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The active material layer 2 is formed by coating a coating solution 21, which is prepared by kneading an organic solvent with a conductive material such as acetylene black and a resin binder such as polyvinylidene fluoride (PVdF), onto the electrode foil 1 using a die coater 9 or the like. The NV (Non-volatile Organic Compound) value of the coating solution 21 for the active material layer 2 is, for example, about 70 to 80%. The thickness of the active material layer 2 is, for example, about 50 μm to 200 μm.

[0020] The protective layer 3 is formed by applying a coating liquid 31, which is prepared by kneading insulating ceramic particles (alumina (Al2O3), magnesia (MgO), silica (SiO2), etc.) and a resin binder such as polyvinylidene fluoride (PVdF) in an organic solvent, onto the electrode foil 1 using a spray nozzle 5. The NV value of the coating liquid 31 for the protective layer 3 is, for example, about 20 to 30%. The thickness t of the protective layer 3 is, for example, about 10 μm to 15 μm. The predetermined width w of the protective layer 3 is, for example, about 4 mm to 6 mm.

[0021] The coating liquid shielding mechanism 4K also includes a drive unit 42 that rotates the shielding member 4 to move the coating liquid 31H attached to the shielding member 4 in a direction away from the opening 41. Specifically, the coating liquid shielding mechanism 4K includes a pair of cylindrical shielding members 4 that are arranged on the left and right sides of the opening 41 in the width direction (Z direction) and extend horizontally and parallel in the longitudinal direction (X direction), a drive unit 42 that rotates each shielding member 4 in the circumferential direction, and a scraper 43 whose tip end 431 contacts the outer circumferential surface 411 of each shielding member 4. The scraper 43 contacts the outer circumferential surface 411 of the shielding member 4 on the side opposite to the opening 41.

[0022] The gap w between the outer peripheral surfaces 411 of the pair of cylindrical shielding members 4 becomes the opening 41 of the shielding member 4, and is equal to the predetermined width w of the protective layer 3. The driving unit 42 operates so that the outer peripheral surface 411 of each shielding member 4 rotates from below to above in the opening 41.

[0023] The spray nozzle 5 also radially discharges the coating liquid 31 of the protective layer 3 from a slit-shaped nozzle opening 51 formed at the bottom end. Of the fine particles of the coating liquid 31 discharged radially from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 distributed at a relatively uniform density in the center of the nozzle pass through the opening 41 of the cylindrical shielding member 4 and are coated onto the electrode foil 1 within a predetermined width w of the protective layer 3.

[0024] On the other hand, among the fine particles of the coating liquid 31 radially ejected from the spray nozzle 5, the fine particles 31b distributed at a relatively non-uniform density around the nozzle adhere to the outer peripheral surface 411 of the cylindrical shielding member 4. Furthermore, since the drive unit 42 operates to rotate the outer peripheral surface 411 of each shielding member 4 from bottom to top at the opening 41, the coating liquid 31H adhered to the outer peripheral surface 411 of the shielding member 4 moves in a direction away from the opening 41. This prevents the coating liquid 31H adhered to the outer peripheral surface 411 of the shielding member 4 from dripping from the opening 41 and adhering to the protective layer 3, which would cause the thickness t of the protective layer 3 to become non-uniform. As a result, the thickness t of the protective layer 3 of the electrode body 10 can be made even more uniform.

[0025] Furthermore, the coating liquid 31H that has moved in a direction away from the opening 41 is scraped off and collected by the scraper 43, the tip 431 of which is in contact with the outer peripheral surface 411 of the shielding member 4. The coating liquid shielding mechanism 4K also includes a coating liquid recovery and reuse system 6 that recovers and reuses the coating liquid 31 shielded by the shielding member 4.

[0026] That is, the coating liquid recovery and reuse system 6 includes a recovery tank 62 that recovers the coating liquid 31 scraped off by the scraper 43 via a recovery pipe 61, a solids content adjustment tank 64 that recovers the coating liquid 31 stored in the recovery tank 62 via a second recovery pipe 63 and adjusts the solids content to an appropriate state, a liquid supply tank 66 that recovers the adjusted coating liquid 31 stored in the solids content adjustment tank 64 via a third recovery pipe 65, a coating liquid supply system 68 that supplies new coating liquid 31 to the liquid supply tank 66, and a delivery pipe 67 that delivers the coating liquid 31 stored in the liquid supply tank 66 to the spray nozzle 5. A delivery pump P is installed in each of the recovery pipe 61, the second recovery pipe 63, the third recovery pipe 65, the delivery pipe 67, etc.

[0027] In this way, the coating liquid shielding mechanism 4K is provided with the coating liquid recovery and reuse system 6, and therefore the recovered coating liquid 31 shielded by the shielding member 4 can be reused in a fresh state, thereby improving the yield of the coating liquid 31 while maintaining the quality of the protective layer 3. Therefore, it is possible to uniformize the thickness t of the protective layer 3 and, at the same time, to provide an electrode body 10 that is excellent in quality and cost.

[0028] <Modification> The present embodiment described in detail above is merely an example and does not limit the disclosed technology in any way. Therefore, the disclosed technology can be improved and modified in various ways without departing from the spirit and scope of the invention. Representative modified examples of the coating liquid shielding mechanism 4K will be described below with reference to the drawings.

[0029] (Variation 1) Fig. 4 shows an enlarged cross-sectional view of Modification 1 of portion A shown in Fig. 1. As shown in Fig. 4, the coating liquid shielding mechanism 4BK of Modification 1 includes a drive unit 42B that rotates the shielding member 4B to move the coating liquid 31H attached to the shielding member 4B in a direction away from the opening 41B. Specifically, the coating liquid shielding mechanism 4BK includes the drive unit 42B, which is composed of a plurality of (e.g., four) roller bodies 421B arranged on the left and right sides of the width direction (Z direction) of the opening 41B and extending horizontally and parallel in the longitudinal direction (X direction), a pair of annular shielding members 4B composed of belt bodies wound around the roller bodies 421B, and scrapers 43B, each of which has a tip 431B in contact with an outer circumferential surface 411B of each shielding member 4B.

[0030] The gap w between the outer peripheral surfaces 411B of the pair of annular shielding members 4B forms the opening 41B of the shielding members 4B, and is equal to the predetermined width w of the protective layer 3. The driving unit 42B operates so that the outer peripheral surface 411B of each shielding member 4B moves from below to above in the opening 41B. Here, the outer peripheral surface 411B of each shielding member 4B forms a vertical shielding surface between the upper and lower roller bodies 421B in the opening 41B.

[0031] The spray nozzle 5 radially discharges the coating liquid 31 of the protective layer 3 from a slit-shaped nozzle opening 51 formed at the bottom end. Of the fine particles of the coating liquid 31 radially discharged from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 distributed at a relatively uniform density in the center of the nozzle pass through the openings 41B of the annular shielding member 4B and are applied to the electrode foil 1 over a predetermined width w of the protective layer 3. The outer peripheral surface 411B of each shielding member 4B forms a vertical shielding surface between the upper and lower roller bodies 421B at the openings 41B, thereby preventing the fine particles 31a of the coating liquid 31 passing through the openings 41B from diffusing in the width direction (Z direction). This makes it possible to further uniformize the thickness t of the protective layer 3.

[0032] Meanwhile, among the fine particles of the coating liquid 31 radially ejected from the spray nozzle 5, the fine particles 31b distributed at a relatively non-uniform density around the nozzle adhere to the outer peripheral surface 411B of the annular shielding member 4B, which is located outside the opening 41B. Furthermore, since the driving unit 42B operates to move the outer peripheral surface 411B of each shielding member 4B from below to above the opening 41B, the coating liquid 31H adhered to the outer peripheral surface 411B of the shielding member 4B moves in a direction away from the opening 41B. This prevents the coating liquid 31H adhered to the outer peripheral surface 411B of the shielding member 4B from dripping from the opening 41B and adhering to the protective layer 3, which would otherwise cause the thickness t of the protective layer 3 to become non-uniform. As a result, the thickness t of the protective layer 3 of the electrode body 10 can be made even more uniform.

[0033] Alternatively, a DC power supply DX may be connected to the spray nozzle 5 and the shielding member 4B to apply an electrostatic field, thereby charging the fine particles of the coating liquid 31 discharged from the spray nozzle 5 and the shielding member 4B to the same polarity (e.g., positive). In this case, the fine particles 31a of the coating liquid 31 passing through the opening 41B are less likely to adhere to the outer peripheral surface 411B of the shielding member 4B, further reducing dripping from the opening 41B. Note that the coating liquid 31H moving away from the opening 41B is scraped and recovered by the scraper 43B, whose tip 431B contacts the outer peripheral surface 411B of the shielding member 4B. The recovered coating liquid 31 is then resupplied to the spray nozzle 5 by the coating liquid recovery and reuse system 6. This improves the yield of the coating liquid 31 while maintaining the quality of the protective layer 3.

[0034] (Variation 2) Fig. 5 shows an enlarged cross-sectional view of Modification 2 of portion A shown in Fig. 1. As shown in Fig. 5, the coating liquid shielding mechanism 4CK of Modification 2 includes a drive unit 42C that rotates the shielding member 4C to move the coating liquid 31H attached to the shielding member 4C in a direction away from the opening 41C. Specifically, the coating liquid shielding mechanism 4CK includes a conical shielding member 4C that expands in diameter upward from a circular opening 41C located below, a drive unit 42C that rotates the conical shielding member 4C horizontally around the opening 41C, and a receiving trough 43C for collecting the coating liquid located below the outer edge of the shielding member 4C. The inner diameter w of the circular opening 41C is equal to the predetermined width w of the protective layer 3. The driving unit 42C includes a first gear portion 421C that rotates around a vertical axis, and a second gear portion 422C that meshes with the first gear portion 421C to rotate the shielding member 4C in the horizontal direction around the opening 41C. The second gear portion 422C is formed as an annular gear and is fixed to the back side of the conical shielding member 4C.

[0035] The spray nozzle 5 also radially discharges the coating liquid 31 of the protective layer 3 from a slit-shaped nozzle opening 51 formed at the bottom end. Of the fine particles of the coating liquid 31 discharged radially from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 distributed at a relatively uniform density in the center of the nozzle pass through the opening 41C of the conical shielding member 4C and are applied to the electrode foil 1 within a predetermined width w of the protective layer 3.

[0036] Meanwhile, among the fine particles of the coating liquid 31 radially ejected from the spray nozzle 5, fine particles 31b distributed at a relatively non-uniform density around the nozzle adhere to the upper surface of the conical shielding member 4C. Furthermore, because the driving unit 42C rotates the conical shielding member 4C horizontally, the coating liquid 31H adhered to the upper surface of the shielding member 4C moves away from the opening 41C due to centrifugal force. This prevents the coating liquid 31H adhered to the upper surface of the shielding member 4C from dripping from the opening 41C and adhering to the protective layer 3, which would otherwise cause the thickness t of the protective layer 3 to become non-uniform. As a result, the thickness t of the protective layer 3 of the electrode body 10 can be made even more uniform.

[0037] Preferably, a liquid stop dam 411C standing upward in a circular shape is formed at the opening 41C of the shielding member 4C. The liquid stop dam 411C can further prevent liquid from dripping from the opening 41C. Furthermore, a plurality of second liquid stop dams 412C extending radially from the opening 41C toward the outer edge may be formed on the upper surface of the shielding member 4C. The coating liquid 31H moving away from the opening 41B is dispersed approximately evenly by the second liquid stop dams 412C and collected in the receiving trough 43C. The collected coating liquid 31 is supplied again to the spray nozzle 5 by the coating liquid recovery and reuse system 6. This improves the yield of the coating liquid 31 while maintaining the quality of the protective layer 3.

[0038] (Variation 3) FIG. 6 shows an enlarged cross-sectional view of Modification Example 3 of the portion A shown in FIG. 1. As shown in FIG. 6, the coating liquid shielding mechanism 4DK of Modification Example 3 has a structure in which a shielding member 4D is installed that is inclined obliquely downward relative to the opening 41D, and the coating liquid 31H attached to the shielding member 4D is moved away from the opening 41D by gravity. Specifically, the coating liquid shielding mechanism 4DK includes a pair of shielding members 4D arranged on either side of the opening 41D in the width direction (Z direction), each extending in the longitudinal direction (X direction) with its tip end 411D adjacent to the opening 41D formed at an acute angle, and a receiving trough 43D for collecting the coating liquid on the back surface 45D of the shielding member 4D. The gap w between the tip ends 411D of the pair of shielding members 4D forms the opening 41D of the shielding member 4D and coincides with the predetermined width w of the protective layer 3.

[0039] The spray nozzle 5 also radially discharges the coating liquid 31 of the protective layer 3 from a slit-shaped nozzle opening 51 formed at the bottom end. Of the fine particles of the coating liquid 31 discharged radially from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 distributed at a relatively uniform density in the center of the nozzle pass through the opening 41D of the shielding member 4D and are coated onto the electrode foil 1 within a predetermined width w of the protective layer 3.

[0040] Meanwhile, among the fine particles of the coating liquid 31 radially ejected from the spray nozzle 5, fine particles 31b distributed at a relatively non-uniform density around the nozzle adhere to the inclined upper surface 44D of the shielding member 4D. The coating liquid 31H adhered to the inclined upper surface 44D of the shielding member 4D moves away from the opening 41D due to gravity. The coating liquid 31H adhered to the back surface 45D of the shielding member 4D also moves away from the opening 41D due to gravity and is collected in the collection receiving trough 43D. This prevents the coating liquid 31H adhered to the shielding member 4D from dripping from the opening 41D and adhering to the protective layer 3, which would otherwise cause the thickness t of the protective layer 3 to become non-uniform. As a result, the thickness t of the protective layer 3 of the electrode body 10 can be made even more uniform. The coating liquid shielding mechanism 4DK also includes a coating liquid recovery and reuse system 6 that recovers and reuses the coating liquid 31 shielded by the shielding member 4D. The recovered coating liquid 31 is supplied again to the spray nozzle 5 by the coating liquid recovery and reuse system 6. This makes it possible to improve the yield of the coating liquid 31 while maintaining the quality of the protective layer 3.

[0041] (Variation 4) FIG. 7 shows an enlarged cross-sectional view of Modification 4 of the portion A shown in FIG. 1. As shown in FIG. 7, the coating liquid shielding mechanism 4EK of Modification 4 is configured to install a shielding member 4E that is inclined obliquely downward relative to the opening 41E, and to move the coating liquid 31H attached to the shielding member 4E away from the opening 41E by gravity. Specifically, the coating liquid shielding mechanism 4EK includes a pair of shielding members 4E arranged on either side of the opening 41E in the width direction (Z direction), each extending in the longitudinal direction (X direction) with its tip end 411E adjacent to the opening 41E formed at an acute angle, and a suction duct 46E for suctioning the coating liquid on the back side of the shielding member 4E. The gap w between the tip ends 411E of the pair of shielding members 4E forms the opening 41E of the shielding member 4E and coincides with the predetermined width w of the protective layer 3.

[0042] The spray nozzle 5 also radially discharges the coating liquid 31 of the protective layer 3 from a slit-shaped nozzle opening 51 formed at the bottom end. Of the fine particles of the coating liquid 31 discharged radially from the spray nozzle 5, only the fine particles 31a of the coating liquid 31 distributed at a relatively uniform density in the center of the nozzle pass through the opening 41E of the shielding member 4E and are coated onto the electrode foil 1 within a predetermined width w of the protective layer 3.

[0043] Meanwhile, among the fine particles of the coating liquid 31 radially ejected from the spray nozzle 5, fine particles 31b distributed at a relatively non-uniform density around the nozzle adhere to the inclined upper surface 44E of the shielding member 4E. The coating liquid 31H adhered to the inclined upper surface 44E of the shielding member 4E moves away from the opening 41E due to gravity. Furthermore, the coating liquid 31Q that falls and floats on the back side of the shielding member 4E is collected in the suction duct 46E. This prevents the coating liquid 31H adhered to the shielding member 4E from dripping from the opening 41E and adhering to the protective layer 3, resulting in an uneven thickness t of the protective layer 3. As a result, the thickness t of the protective layer 3 of the electrode assembly 10 can be made even more uniform. The coating liquid shielding mechanism 4EK also includes a coating liquid recovery and reuse system 6 that recovers and reuses the coating liquid 31 shielded by the shielding member 4E. The recovered coating liquid 31 is supplied again to the spray nozzle 5 by the coating liquid recovery and reuse system 6. Therefore, the yield of the coating liquid 31 can be improved while maintaining the quality of the protective layer 3. [Explanation of symbols]

[0044] 1 Electrode foil 2 Active material layer 2S side edge 3 protective layer 4, 4B, 4C, 4D, 4E Shielding member 4K, 4BK, 4CK, 4DK, 4EK Coating liquid shielding mechanism 5 spray nozzles 6 Coating fluid recovery and reuse system 10 Electrode body 31, 31H coating liquid 41, 41B, 41C, 41D, 41E opening 42, 42B, 42C drive unit S3 Protective layer coating process w Specified width

Claims

1. A method for manufacturing an electrode assembly, comprising a protective layer coating step of coating an electrode foil (1) with a protective layer adjacent to a side edge portion of an active material layer in a predetermined width, In the protective layer coating step, a coating liquid shielding mechanism is provided in which a shielding member having an opening with the predetermined width of the protective layer is disposed at a position spaced above the electrode foil, and the coating liquid of the protective layer is sprayed onto the electrode foil from a spray nozzle disposed above the center of the opening in the width direction. A method for manufacturing an electrode body.

2. The method for manufacturing an electrode assembly according to claim 1, The coating liquid shielding mechanism includes a drive unit that rotates the shielding member to move the coating liquid attached to the shielding member in a direction away from the opening. A method for manufacturing an electrode body.

3. The method for manufacturing an electrode assembly according to claim 1 or 2, The coating liquid shielding mechanism includes a coating liquid recovery and reuse system that recovers and reuses the coating liquid shielded by the shielding member. A method for manufacturing an electrode body.

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