Method for manufacturing electrode plate and device for manufacturing electrode plate

Abstract

The disclosed method for manufacturing an electrode plate comprises a conveying step for conveying a band-form electrode plate (60) having a first main surface (61) and a second main surface (62) on the opposite side to the first main surface (61) in a predetermined conveying direction (D1), and a display formation step for forming an identification display unit (63) on the first main surface (61) of the conveyed electrode plate (60). In the conveying step, the second main surface (62) of the electrode plate (60) that is conveyed while the identification display unit (63) is formed is supported by three or more rollers (21) aligned in the conveying direction (D1).

Description

Electrode plate manufacturing method and electrode plate manufacturing device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims the benefit of priority to Japanese Patent Application No. 2024-104730, filed on June 28, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a method and an apparatus for manufacturing an electrode plate.

[0003] Conventionally, there has been known a technique for forming an identification marking (i.e., a marking having some kind of identification information) on a strip-shaped electrode plate (or current collector) (for example, Patent Document 1). Patent Document 1 discloses a method for manufacturing an intermittently coated battery electrode, which comprises forming a tip indicator indicating the tip of an active material layer to be intermittently coated on a strip-shaped current collector in a portion where no active material is coated, coating an active material on a first surface of the current collector based on a detection signal from the tip indicator to form an intermittently coated layer, and then starting to coat an intermittently coated layer on a second surface opposite the first surface using the same tip indicator as that used when forming the active material coated layer on the first surface based on the detection signal from the tip indicator).

[0004] International Publication No. 2015 / 019711

[0005] However, when forming such an identification marking (or the tip indicator in Patent Document 1) on an electrode plate, the identification marking may not be formed with high precision due to, for example, bending of the electrode plate. In such cases, it becomes difficult to read desired information from the identification marking. In such circumstances, one of the objectives of the present disclosure is to form an identification marking with high precision.

[0006] One aspect of the present disclosure relates to a method for manufacturing an electrode plate, the method comprising: a conveying step of conveying a strip-shaped electrode plate having a first main surface and an opposite second main surface in a predetermined conveyance direction; and a marking step of forming an identification mark on the first main surface of the electrode plate being conveyed, wherein the second main surface of the electrode plate being conveyed while the identification mark is being formed is supported by three or more rollers aligned in the conveyance direction in the conveyance step.

[0007] Another aspect of the present disclosure relates to an electrode plate manufacturing apparatus including: a conveying unit configured to convey a strip-shaped electrode plate having a first main surface and an opposite second main surface in a predetermined conveying direction; and a marking forming unit configured to form an identification marking on the first main surface of the conveyed electrode plate, wherein the conveying unit has three or more rollers arranged side by side in the conveying direction and supporting the second main surface of the electrode plate while the identification marking is being formed on the second main surface of the electrode plate being conveyed.

[0008] According to the present disclosure, it is possible to form an identification marking with high precision. 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 invention, will be better understood from the following detailed description taken in conjunction with the drawings.

[0009] 1 is a front view schematically illustrating an example of an electrode plate manufacturing apparatus according to the present disclosure; FIG. 2 is an enlarged front view illustrating dimensions related to three or more rollers;

[0010] The following describes an example of an embodiment of an electrode plate manufacturing method and an electrode plate manufacturing apparatus according to the present disclosure. However, the present disclosure is not limited to the example described below. In the following description, specific numerical values ​​and materials may be used as examples, but other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained.

[0011] (Method for manufacturing an electrode plate) The method for manufacturing an electrode plate according to the present disclosure may be a method for manufacturing an electrode plate for use in a battery or a capacitor, and includes a conveying step and a display forming step. Hereinafter, an electrode plate for use in a non-aqueous electrolyte secondary battery (e.g., a lithium ion secondary battery) will be described as an example, but the use of the electrode plate is not limited thereto. Note that in the present disclosure, the category of secondary battery also includes an electricity storage device (e.g., a lithium ion capacitor) in which at least one of the positive electrode and the negative electrode is an electrode that exhibits capacity through a non-Faradic reaction.

[0012] A strip-shaped electrode plate having a first main surface and an opposite second main surface is transported in a predetermined transport direction. The transport direction may be horizontal or vertical, or may intersect the horizontal and vertical directions. The electrode plate may have a strip-shaped metal foil made of, for example, aluminum, an aluminum alloy, stainless steel, titanium, a titanium alloy, copper, a copper alloy, nickel, a nickel alloy, or the like, and an active material layer formed on the surface of the metal foil, which may contain, for example, an active material, a conductive agent, a binder, a thickener, or the like.

[0013] Examples of active materials include composite metal oxides of lithium with transition metals such as cobalt, manganese, and nickel, and carbon materials such as natural graphite, spherical or fibrous artificial graphite, non-graphitizable carbon (hard carbon), and easily graphitizable carbon (soft carbon).The active materials may be used alone or in combination of two or more.

[0014] The conductive agent may be carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black, or conductive fibers such as carbon fiber or metal fiber. The conductive agent for the positive electrode may be various graphites such as natural graphite and artificial graphite.

[0015] The binder is not particularly limited as long as it can be dissolved or dispersed in the dispersion medium by kneading. Examples of binders include fluororesins, rubbers, acrylic polymers, or vinyl polymers (e.g., homopolymers or copolymers of monomers such as acrylic monomers such as methyl acrylate and acrylonitrile, and vinyl monomers such as vinyl acetate). Examples of fluororesins include polyvinylidene fluoride, copolymers of vinylidene fluoride and propylene hexafluoride, and polytetrafluoroethylene. Examples of rubbers include acrylic rubber, modified acrylonitrile rubber, and styrene butadiene rubber (SBR). The binder may be used alone or in combination of two or more. Generally, fluororesins are preferred as binders for the positive electrode, and fluororesins and rubbers are preferred as binders for the negative electrode.

[0016] In the mark forming process, an identification mark is formed on the first main surface of the electrode plate being transported. The identification mark may be an identification mark that can identify the history of the manufacturing process. The identification mark may be a QR code (registered trademark), which is a two-dimensional code, but is not limited to this. For example, the identification mark may be composed of numbers, letters, or a combination of numbers and letters, or may be composed of protrusions, holes, or a combination of protrusions and holes. The identification mark may also be a one-dimensional code such as a barcode. The identification mark may be formed, for example, by irradiating the first main surface of the electrode plate with a laser. When the identification mark is rectangular, the length of one side may be, for example, 2 mm or more and 5 mm or less.

[0017] Here, if the electrode plate warps during transport, it becomes difficult to form an identification marking on the first main surface of the electrode plate with high precision. In contrast, in the electrode plate manufacturing method according to the present disclosure, the second main surface of the electrode plate being transported while the identification marking is being formed is supported by three or more rollers aligned in the transport direction during the transport step. This prevents the electrode plate from warping in the region for forming the identification marking during transport, enabling the identification marking to be formed with high precision. Since each roller can rotate while supporting the electrode plate, the second main surface of the electrode plate is not substantially damaged by contact with the rollers. Each roller may have a rotation axis extending parallel to the width direction of the electrode plate being transported. The rotation axes of the three or more rollers may extend parallel to each other. The axial length of the three or more rollers may be, for example, 1 m or more and 2 m or less. The material of the three or more rollers is not particularly limited and may be, for example, stainless steel, aluminum, urethane rubber, or the like. The material of the three or more rollers is typically stainless steel. The number of rollers is not particularly limited as long as it is three or more, and may be, for example, three or more and fifteen or less.

[0018] The center-to-center distance between the three or more rollers in the conveying direction may be 10 mm or more and 60 mm or less. When the center-to-center distance is within this range, the rollers are not arranged too closely, and deflection of the electrode plate during conveyance can be sufficiently suppressed.

[0019] The diameter of the three or more rollers is D, and the center-to-center distance between the three or more rollers in the conveying direction may be D or more and 6D or less. When the center-to-center distance is within this range, the rollers are not arranged too closely, and deflection of the electrode plate during conveyance can be sufficiently suppressed. The center-to-center distance may be D or more and 4D or less, or D or more and 3D or less. The diameter D of each roller may be, for example, 5 mm or more and 60 mm or less. The diameters of the three or more rollers may be the same or different. When the diameters of the three or more rollers are different, the diameter D is the average value of the diameters of the three or more rollers.

[0020] In the conveying process, tension may be applied to the electrode plate by a pair of large-diameter rollers arranged on both sides of the three or more rollers in the conveying direction and having a diameter larger than that of the three or more rollers. Such tension application can further suppress deflection of the electrode plate during conveyance. The rotation axis of each large-diameter roller may extend parallel to the rotation axis of the other roller. The diameter of the large-diameter roller may be, for example, 80 mm or more and 150 mm or less. The diameter of the large-diameter roller may be, for example, 3D or more and 10D or less, where D is the diameter of the three or more rollers. The large-diameter rollers may actively rotate in accordance with the conveying speed of the electrode plate, or may passively rotate due to frictional force received from the electrode plate. The material of the pair of large-diameter rollers is not particularly limited and may be, for example, stainless steel, aluminum, urethane rubber, or the like. The pair of large-diameter rollers is typically made of stainless steel. Note that "three or more rollers" can also be referred to as "three or more small-diameter rollers" in the sense that the small-diameter rollers have a diameter smaller than that of the pair of large-diameter rollers.

[0021] In the normal direction of the electrode plate, the circumferential surface positions (hereinafter also referred to as first circumferential surface positions) of the three or more rollers closest to the electrode plate may be located closer to the electrode plate than the circumferential surface positions (hereinafter also referred to as second circumferential surface positions) of the pair of large-diameter rollers closest to the electrode plate. In other words, the three or more rollers may protrude closer to the electrode plate than the pair of large-diameter rollers. With this configuration, the three or more rollers can more reliably support the second main surface of the electrode plate during transport. In the normal direction of the electrode plate, the distance between the first circumferential surface position and the second circumferential surface position may be, for example, 3 mm or more and 15 mm or less.

[0022] In the conveying step, three or more rollers supporting the second main surface of the electrode plate may be actively rotated. The rotation direction of the three or more rollers may be such that the electrode plate-side end of each roller moves along the conveying direction. The rotation speed of the three or more rollers may be set so that the peripheral speed of each roller substantially matches the conveying speed of the electrode plate. Here, "substantially matching" the peripheral speed of each roller and the conveying speed of the electrode plate means that the latter is 0.95 S or more and 1.05 S or less, where S (reference value) is the former. This configuration reduces friction between the electrode plate and each roller, further suppressing damage to the second main surface of the electrode plate.

[0023] The three or more rollers may be arranged so that the deflection of the electrode plate supported by the three or more rollers is 0.3 mm or less. This allows the identification marking to be formed with even higher precision. Here, the deflection of the electrode plate refers to the deflection of the electrode plate between adjacent rollers. The deflection is preferably 0.25 mm or less, and more preferably 0.15 mm or less.

[0024] (Electrode Plate Manufacturing Apparatus) The electrode plate manufacturing apparatus according to the present disclosure may be an apparatus for manufacturing electrode plates to be used in batteries, and includes a conveying unit and a display forming unit.

[0025] The conveying section conveys a strip-shaped electrode plate having a first main surface and a second main surface opposite to the first main surface in a predetermined conveying direction.

[0026] The marking unit forms an identification marking on the first main surface of the electrode plate being transported. The marking unit may include, for example, a laser printer or an inkjet printer.

[0027] The conveying unit has three or more rollers arranged side by side in the conveying direction and supporting the second main surface of the electrode plate being conveyed while the identification marking is being formed, thereby suppressing deflection of the electrode plate during conveyance in the area for forming the identification marking, and enabling the identification marking to be formed with high precision.

[0028] The conveying unit may further include a pair of large-diameter rollers that are arranged on both sides of the three or more rollers in the conveying direction, have a diameter larger than that of the three or more rollers, and apply tension to the electrode plate, thereby further suppressing bending of the electrode plate during conveyance.

[0029] The transport unit may actively rotate three or more rollers that support the second main surface of the electrode plate, thereby further reducing damage to the second main surface of the electrode plate.

[0030] As described above, according to the present disclosure, by supporting the second main surface of the electrode plate during transport with three or more rollers, it is possible to form an identification marking on the first main surface of the electrode plate with high accuracy. Furthermore, according to the present disclosure, since the identification marking is formed on the electrode plate while it is being transported, it is possible to manufacture electrode plates with identification markings formed thereon with high productivity.

[0031] Below, an example of an electrode plate manufacturing method and an electrode plate manufacturing apparatus according to the present disclosure will be described in detail with reference to the drawings. The above-described steps and components can be applied to the steps and components of the example electrode plate manufacturing method and electrode plate manufacturing apparatus described below. The steps and components of the example electrode plate manufacturing method and electrode plate manufacturing apparatus described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above-described embodiment. Among the steps and components of the example electrode plate manufacturing method and electrode plate manufacturing apparatus described below, steps and components that are not essential to the electrode plate manufacturing method and electrode plate manufacturing apparatus according to the present disclosure may be omitted. Note that the diagrams shown below are schematic and do not accurately reflect the actual shapes and numbers of components.

[0032] As shown in FIGS. 1 and 2, the electrode plate manufacturing apparatus 10 of this embodiment includes a conveying section 20, a laser printer 30, an unwinding roller 41, and a winding roller .

[0033] The conveying unit 20 conveys a strip-shaped electrode plate 60 having a first main surface 61 and a second main surface 62 opposite thereto in a predetermined conveying direction D1 (from left to right in FIG. 1 in this example). The conveying unit 20 has three or more (seven in the illustrated example) rollers 21 arranged side by side in the conveying direction D1 and supporting the second main surface 62 of the electrode plate 60 as it is conveyed while an identification marking portion 63 is formed by the laser printer 30. The center-to-center distance CD of the three or more rollers 21 in the conveying direction D1 is preferably 10 mm or more and 60 mm or less. Furthermore, where D is the diameter of the three or more rollers 21, the center-to-center distance CD of the three or more rollers 21 in the conveying direction D1 is preferably D or more and 6D or less. Furthermore, the three or more rollers 21 are preferably arranged so that the deflection of the electrode plate 60 supported by the three or more rollers 21 is 0.3 mm or less.

[0034] The conveying unit 20 further includes a pair of large-diameter rollers 22 arranged on both sides of the three or more rollers 21 in the conveying direction D1. The diameter of the pair of large-diameter rollers 22 is larger than the diameter of the three or more rollers 21. The pair of large-diameter rollers 22 apply tension to the electrode plate 60. In the normal direction of the electrode plate 60 (in this example, the vertical direction in FIGS. 1 and 2 ), the circumferential surface positions (first circumferential surface positions) of the three or more rollers 21 closest to the electrode plate 60 (in this example, the upper side in FIGS. 1 and 2 ) are preferably located closer to the electrode plate 60 than the circumferential surface positions (second circumferential surface positions) of the pair of large-diameter rollers 22 closest to the electrode plate 60. Note that in FIG. 1 , a line L passing through the second circumferential surface positions of the pair of large-diameter rollers 22 is indicated by a dashed line, and it can be seen that the first circumferential surface positions of each roller 21 are located closer to the electrode plate 60 than the line L (upper side in the illustrated example).

[0035] Preferably, the conveying unit 20 actively rotates three or more rollers 21 that support the second main surface 62 of the electrode plate 60. The rotation speed at this time may be determined based on the conveying speed of the electrode plate 60. In the illustrated example, the rotation direction of the three or more rollers 21 is clockwise.

[0036] The laser printer 30 forms an identification marking portion 63 on the first main surface 61 of the electrode plate 60 being transported by the transport unit 20. In the illustrated example, the laser printer 30 is disposed above three or more rollers 21. The laser printer 30 has a scanning range SR having a predetermined size in the transport direction D1. The size of the scanning range SR in the transport direction D1 may be, for example, 200 mm or more and 500 mm or less. It is preferable that three or more rollers 21 are disposed over substantially the entire scanning range SR in the transport direction (e.g., 90% or more, preferably 95% or more). The laser printer 30 is an example of an indication forming unit. Note that in FIG. 1 , the identification marking portion 63 is illustrated as protruding from the first main surface 61, but this is for ease of understanding. In reality, the identification marking portion 63 does not necessarily have to protrude from the first main surface 61.

[0037] The unwinding roller 41 holds the electrode plate 60 before the identification marking portion 63 is formed. The unwinding roller 41 is a roller for sending the electrode plate 60 before the identification marking portion 63 is formed, via a plurality of upstream rollers 43, etc., to the conveying unit 20. The rotation direction of the unwinding roller 41 is clockwise in the illustrated example.

[0038] The take-up roller 42 takes up and holds the electrode plate 60, on which the identification display portion 63 has been formed, from the conveying unit 20 via a plurality of downstream rollers 44, etc. The rotation direction of the take-up roller 42 is clockwise in the illustrated example.

[0039] <<Additional Notes>> The above embodiments disclose the following techniques. (Technology 1) A method for manufacturing an electrode plate, comprising: a conveying step of conveying a band-shaped electrode plate having a first main surface and a second main surface opposite to the first main surface in a predetermined conveying direction; and a marking forming step of forming an identification mark on the first main surface of the electrode plate being conveyed, wherein in the conveying step, the second main surface of the electrode plate being conveyed while the identification mark is being formed is supported by three or more rollers aligned in the conveying direction. (Technology 2) The method for manufacturing an electrode plate according to Technology 1, wherein the center-to-center distance between the three or more rollers in the conveying direction is 10 mm or more and 60 mm or less. (Technology 3) The method for manufacturing an electrode plate according to Technology 1 or 2, wherein, where D is the diameter of the three or more rollers, the center-to-center distance between the three or more rollers in the conveying direction is D or more and 6D or less. (Technology 4) The method for manufacturing an electrode plate according to any one of Techniques 1 to 3, wherein in the conveying step, tension is applied to the electrode plate by a pair of large-diameter rollers that are arranged on both sides of the three or more rollers in the conveying direction and have a diameter larger than that of the three or more rollers. (Technology 5) The method for manufacturing an electrode plate according to Technique 4, wherein, in the normal direction of the electrode plate, the circumferential surface positions of the three or more rollers closest to the electrode plate are positioned closer to the electrode plate than the circumferential surface positions of the pair of large-diameter rollers closest to the electrode plate. (Technology 6) The method for manufacturing an electrode plate according to any one of Techniques 1 to 5, wherein, in the conveying step, the three or more rollers that support the second main surface of the electrode plate are actively rotated. (Technology 7) The method for manufacturing an electrode plate according to any one of Techniques 1 to 6, wherein the three or more rollers are arranged so that the electrode plate supported by the three or more rollers deflects by 0.3 mm or less. (Technology 8) An electrode plate manufacturing device comprising: a conveying unit that conveys a band-shaped electrode plate, each having a first main surface and a second main surface opposite to the first main surface, in a predetermined conveying direction; and a display forming unit that forms an identification display portion on the first main surface of the electrode plate being conveyed, wherein the conveying unit has three or more rollers that are arranged side by side in the conveying direction and support the second main surface of the electrode plate being conveyed while the identification display portion is being formed thereon.(Technology 9) The electrode plate manufacturing apparatus according to Technology 8, wherein the center-to-center distance of the three or more rollers in the conveying direction is 10 mm or more and 60 mm or less. (Technology 10) The electrode plate manufacturing apparatus according to Technology 8 or 9, wherein the center-to-center distance of the three or more rollers in the conveying direction is D or more and 6D or less, where D is a diameter of the three or more rollers. (Technology 11) The electrode plate manufacturing apparatus according to any one of Technology 8 to 10, wherein the conveying section further includes a pair of large-diameter rollers that are arranged on both sides of the three or more rollers in the conveying direction, have a diameter larger than the three or more rollers, and apply tension to the electrode plate. (Technology 12) The electrode plate manufacturing apparatus according to Technology 11, wherein, in the normal direction of the electrode plate, a circumferential position of the three or more rollers closest to the electrode plate is located closer to the electrode plate than a circumferential position of the pair of large-diameter rollers closest to the electrode plate. (Technology 13) The electrode plate manufacturing apparatus according to any one of Technologies 8 to 12, wherein the transport unit actively rotates the three or more rollers that support the second main surface of the electrode plate. (Technology 14) The electrode plate manufacturing apparatus according to any one of Technologies 8 to 13, wherein the three or more rollers are arranged so that deflection of the electrode plate supported by the three or more rollers is 0.3 mm or less.

[0040] The present disclosure can be used for a method and an apparatus for manufacturing an electrode plate.

[0041] 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.

[0042] 10: Electrode plate manufacturing device 20: Conveying section 21: Roller 22: Large diameter roller 30: Laser printer (indication forming section) 41: Unwinding roller 42: Winding roller 43: Upstream roller 44: Downstream roller 60: Electrode plate 61: First main surface 62: Second main surface 63: Identification indicia CD: Center distance D: Roller diameter D1: Conveying direction L: Straight line SR: Scanning range

Claims

1. A method for manufacturing an electrode plate, comprising: a conveying step of conveying a band-shaped electrode plate having a first main surface and a second main surface opposite to the first main surface in a predetermined conveying direction; and a marking forming step of forming an identification mark on the first main surface of the electrode plate being conveyed, wherein in the conveying step, the second main surface of the electrode plate being conveyed while the identification mark is being formed is supported by three or more rollers aligned in the conveying direction.

2. The method for manufacturing an electrode plate according to claim 1, wherein the distance between the centers of the three or more rollers in the conveying direction is 10 mm or more and 60 mm or less.

3. The method for manufacturing an electrode plate according to claim 1 or 2, wherein the diameter of the three or more rollers is D, and the center-to-center distance between the three or more rollers in the conveying direction is D or more and 6D or less.

4. A method for manufacturing an electrode plate as described in claim 1 or 2, wherein in the conveying step, tension is applied to the electrode plate by a pair of large-diameter rollers arranged on both sides of the three or more rollers in the conveying direction and having a diameter larger than that of the three or more rollers.

5. A method for manufacturing an electrode plate as described in claim 4, wherein, in the normal direction of the electrode plate, the peripheral positions of the three or more rollers closest to the electrode plate are located closer to the electrode plate than the peripheral positions of the pair of large diameter rollers closest to the electrode plate.

6. The method for manufacturing an electrode plate according to claim 1 or 2, wherein in the transporting step, the three or more rollers supporting the second main surface of the electrode plate are actively rotated.

7. A method for manufacturing an electrode plate according to claim 1 or 2, wherein the three or more rollers are arranged so that the deflection of the electrode plate supported by the three or more rollers is 0.3 mm or less.

8. An electrode plate manufacturing device comprising: a conveying section that conveys a band-shaped electrode plate having a first main surface and a second main surface opposite to the first main surface in a predetermined conveying direction; and a display forming section that forms an identification display section on the first main surface of the electrode plate being conveyed, wherein the conveying section has three or more rollers that are arranged side by side in the conveying direction and support the second main surface of the electrode plate being conveyed while the identification display section is being formed thereon.

9. The electrode plate manufacturing device according to claim 8, wherein the distance between the centers of the three or more rollers in the conveying direction is 10 mm or more and 60 mm or less.

10. An electrode plate manufacturing apparatus according to claim 8 or 9, wherein the diameter of the three or more rollers is D, and the center-to-center distance between the three or more rollers in the conveying direction is D or more and 6D or less.

11. An electrode plate manufacturing apparatus as described in claim 8 or 9, wherein the conveying section further includes a pair of large-diameter rollers arranged on both sides of the three or more rollers in the conveying direction, having a diameter larger than the three or more rollers, and applying tension to the electrode plate.

12. An electrode plate manufacturing apparatus as described in claim 11, wherein, in the normal direction of the electrode plate, the peripheral positions of the three or more rollers closest to the electrode plate are located closer to the electrode plate than the peripheral positions of the pair of large diameter rollers closest to the electrode plate.

13. The electrode plate manufacturing apparatus according to claim 8 or 9, wherein the transport unit actively rotates the three or more rollers that support the second main surface of the electrode plate.

14. An electrode plate manufacturing apparatus according to claim 8 or 9, wherein the three or more rollers are arranged so that the deflection of the electrode plate supported by the three or more rollers is 0.3 mm or less.

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