Compression roll device and electrode sheet manufacturing method

Abstract

To heat both end parts of the compression roll of a compression roll device with a simple configuration.SOLUTION: A compression roll device 10 includes: a pair of compression rolls 20 for compressing an electrode sheet 5 by holding the electrode sheet 5; and an electromagnetic induction generation device 60 provided in both end parts of the compression roll 20 in an axial direction D1 to be separate from each other, the electromagnetic induction generation device generating an electromagnetic induction and induction-heating both ends of the compression roll 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a compression roll device and a method for producing an electrode sheet, and more particularly to a compression roll device for compressing an electrode sheet and a method for producing an electrode sheet using the compression roll device. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2022-127326 discloses a heat-generating roller device including a pair of rotatably supported hollow cylindrical roller bodies, an induction heating mechanism provided inside the roller bodies, and a cooling mechanism that supplies a refrigerant to the roller bodies. The induction heating mechanism has a cylindrical iron core extending in the axial direction of the roller bodies and an induction coil wound around the outer circumferential surface of the cylindrical iron core. The cooling mechanism is provided around the induction coil within the roller bodies and has a refrigerant flow path through which the refrigerant is supplied.

[0003] In this heat-generating roller device, the roller body can be heated by passing a current through the induction coil, and the roller body can be cooled by passing a refrigerant through a refrigerant flow path within the roller body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-127326 Summary of the Invention [Problem to be solved by the invention]

[0005] The heat-generating roller device disclosed in JP 2022-127326 A has an induction heating mechanism for heating and a cooling mechanism for cooling inside the roller body, which makes the heat-generating roller device configuration complicated. [Means for solving the problem]

[0006] The compression roll device disclosed herein includes a pair of compression rolls that sandwich and compress an electrode sheet, and an electromagnetic induction generator that is provided at a distance from both axial ends of the compression rolls and generates electromagnetic induction to inductively heat both ends of the compression rolls.

[0007] According to the compression roll device, both ends of the pair of compression rolls can be heated by induction heating generated by an electromagnetic induction generator. By heating both ends of the compression rolls by induction heating in this way, the compression rolls can be heated with a simpler configuration than conventional methods. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view schematically illustrating a compression roll device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating an example of an electrode sheet. [Figure 3] FIG. 2 is a front view showing a compression roll device according to an embodiment, and is a diagram schematically showing a compression roll and a coil of an electromagnetic induction generator. [Figure 4] FIG. 2 is a side view of the compression roll device according to the embodiment, as viewed from the axial direction, and is a diagram schematically illustrating the compression roll and the coil of the electromagnetic induction generator. [Figure 5] FIG. 2 is a block diagram of a compression roll device according to an embodiment. [Figure 6] 1 is a flowchart showing a method for producing an electrode sheet. [Figure 7] FIG. 4 is a view equivalent to FIG. 3 showing a compression roll device according to a modified example. [Figure 8] 4 and shows a compression roll device according to a modified example. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the technology disclosed herein will be described below with reference to the drawings. Note that the embodiment described herein is not intended to limit the invention described in the claims of this application. The drawings are schematic and do not necessarily faithfully reflect actual implementations. Furthermore, components and parts that perform the same function are appropriately designated by the same reference numerals, and duplicate explanations will be omitted where appropriate.

[0010] FIG. 1 is a front view schematically illustrating a compression roll device 10 according to this embodiment. As shown in FIG. 1, the compression roll device 10 according to this embodiment is a device that compresses an electrode sheet 5. The type of electrode sheet 5 is not particularly limited. For example, the electrode sheet 5 is one used in so-called secondary batteries. The secondary battery referred to here is a battery that can be repeatedly charged and discharged by the movement of charge carriers between a pair of electrodes (e.g., a positive electrode and a negative electrode) via an electrolyte. The electrode sheet 5 is housed in a wound or stacked state in a case filled with an electrolyte.

[0011] FIG. 2 is a cross-sectional view schematically illustrating an example of an electrode sheet 5. As shown in FIG. 2, the electrode sheet 5 includes a sheet-shaped current collector 6 and an electrode active material layer 7 formed on the surface of the current collector 6 and containing an electrode active material. In the example shown in FIG. 2, the electrode active material layer 7 is formed on both sides of the current collector 6, but it may be formed on one side of the current collector 6. Here, when the electrode sheet 5 is a sheet for a positive electrode, the current collector 6 is made of a metal having good conductivity, such as aluminum, nickel, titanium, or stainless steel. In the electrode active material layer 7 for a positive electrode, a so-called positive electrode active material, such as a lithium composite metal oxide having a layered structure or a spinel structure, may be used as the electrode active material. When the electrode sheet 5 is a sheet for a negative electrode, the current collector 6 is made of a metal having good conductivity, such as copper (copper foil) or a copper-based alloy. In the electrode active material layer 7 for the negative electrode, so-called negative electrode active materials, such as particulate (or spherical or flaky) carbon materials at least partially containing a graphite structure (e.g., a layered structure), lithium transition metal composite oxides, lithium transition metal composite nitrides, etc., can be used as the electrode active material.

[0012] The compression roll device 10 shown in FIG. 1 is a device that compresses the electrode sheet 5 described above to compression-mold the current collector 6 and the electrode active material layer 7 of the electrode sheet 5. In this embodiment, as shown in FIG. 1, the compression roll device 10 includes a pair of compression rolls 20. The pair of compression rolls 20 sandwich and compress the electrode sheet 5. Here, one of the pair of compression rolls 20 is also referred to as the first compression roll 21, and the other compression roll 20 is also referred to as the second compression roll 22. In this embodiment, the pair of compression rolls 20 are arranged vertically side by side. Here, the first compression roll 21 is arranged above the second compression roll 22. In this embodiment, the electrode sheet 5 is compressed by the rotation of the first compression roll 21 and the second compression roll 22 while the electrode sheet 5 is disposed between the first compression roll 21 and the second compression roll 22.

[0013] In this embodiment, the first compression roll 21 and the second compression roll 22 have the same configuration. In the following, when describing the first compression roll 21 and the second compression roll 22 in common, the term compression roll 20 will be used.

[0014] In this embodiment, the compression roll 20 extends in an axial direction D1. Here, the axial direction D1 is the left-right direction. However, this direction is defined for the convenience of explanation and does not particularly limit this embodiment or aspects of the present invention.

[0015] As shown in FIG. 1, the compression roll 20 has a rotating shaft 25 and a roll body 26. The rotating shaft 25 is rod-shaped and extends in the axial direction D1. The roll body 26 is provided along the circumferential direction of the rotating shaft 25 so as to cover the rotating shaft 25 in the circumferential direction. The roll body 26 is cylindrical and extends in the axial direction D1. Here, the rotating shaft 25 is inserted into the cylindrical roll body 26. The rotating shaft 25 protrudes from one end of the roll body 26 in the axial direction D1 and also protrudes from the other end of the roll body 26 in the axial direction D1. That is, the rotating shaft 25 extends left and right from the roll body 26.

[0016] In this embodiment, the compression roll device 10 includes a device frame 30, a pair of first main support parts 31, a pair of second main support parts 32, a pair of first sub-support parts 33, and a pair of second sub-support parts 34. Here, the first compression roll 21 is rotatably supported by the pair of first main support parts 31 and the pair of first sub-support parts 33. One first main support part 31a rotatably supports one end (here, the left end) of the rotation shaft 25 of the first compression roll 21, and the other first main support part 31b rotatably supports the other end (here, the right end) of the rotation shaft 25 of the first compression roll 21. Here, one first main support part 31a is provided with a first left main bearing 31c, and the rotation shaft 25 of the first compression roll 21 is rotatably inserted into the first left main bearing 31c. The other first main support portion 31b is provided with a first right main bearing 31d, and the rotary shaft 25 of the first compression roll 21 is rotatably inserted into the first right main bearing 31d.

[0017] The pair of first sub-support parts 33 are arranged side by side with the pair of first main support parts 31 in the axial direction D1, outward of the first compression roll 21 with respect to the pair of first main support parts 31. The pair of first sub-support parts 33 rotatably support a portion of the first compression roll 21 that is closer to the end of the rotation shaft 25 supported by the pair of first main support parts 31. Here, one first sub-support part 33a rotatably supports one end of the rotation shaft 25 of the first compression roll 21, and the other first sub-support part 33b rotatably supports the other end of the rotation shaft 25 of the first compression roll 21. More specifically, one first sub-support part 33a is provided with a first left sub-bearing 33c, and the rotation shaft 25 of the first compression roll 21 is rotatably inserted into the first left sub-bearing 33c. The other first sub-support portion 33b is provided with a first right sub-bearing 33d, and the rotary shaft 25 of the first compression roll 21 is rotatably inserted into the first right sub-bearing 33d.

[0018] The second compression roll 22 is rotatably supported by a pair of second main support parts 32 and a pair of second sub-support parts 34. The pair of second main support parts 32 are disposed below the pair of first main support parts 31. One second main support part 32a rotatably supports one end (here, the left end) of the rotating shaft 25 of the second compression roll 22, and the other second main support part 32b rotatably supports the other end (here, the right end) of the rotating shaft 25 of the second compression roll 22. More specifically, one second main support part 32a is provided with a second left main bearing 32c, and the rotating shaft 25 of the second compression roll 22 is rotatably inserted into the second left main bearing 32c. The other second main support part 32b is provided with a second right main bearing 32d, and the rotating shaft 25 of the second compression roll 22 is rotatably inserted into the second right main bearing 32d.

[0019] The pair of second sub-supports 34 are disposed below the pair of first sub-supports 33. The pair of second sub-supports 34 are disposed outward of the pair of second main support parts 32 from the second compression roll 22 and aligned with the pair of second main support parts 32 in the axial direction D1. The pair of second sub-supports 34 rotatably support a portion of the second compression roll 22 that is closer to the end of the rotation shaft 25 supported by the pair of second main support parts 32. Here, one second sub-support part 34a rotatably supports one end of the rotation shaft 25 of the second compression roll 22, and the other second sub-support part 34b rotatably supports the other end of the rotation shaft 25 of the second compression roll 22. More specifically, one second sub-support part 34a is provided with a second left sub-bearing 34c, and the rotation shaft 25 of the second compression roll 22 is rotatably inserted into the second left sub-bearing 34c. The other second sub-support portion 34b is provided with a second right sub-bearing 34d, and the rotary shaft 25 of the second compression roll 22 is rotatably inserted into the second right sub-bearing 34d.

[0020] In this embodiment, the first main support portion 31, the second main support portion 32, the first sub-support portion 33, and the second sub-support portion 34 are supported by the device frame 30. Here, the pair of second main support portions 32 are disposed at fixed positions relative to the device frame 30. The first main support portion 31, the first sub-support portion 33, and the second sub-support portion 34 are configured to be movable in the vertical direction relative to the device frame 30. Here, the pair of first main support portions 31 are provided on the device frame 30 via a main cylinder 40. Therefore, the pair of first main support portions 31 and the first compression roll 21 can move in the vertical direction relative to the device frame 30 via the main cylinder 40, thereby adjusting the distance between the first compression roll 21 and the second compression roll 22. This allows the distance between the first compression roll 21 and the second compression roll 22 to be adjusted depending on the thickness of the electrode sheet 5. By adjusting the distance between the first compression roll 21 and the second compression roll 22, the pressure applied to the electrode sheet 5 sandwiched between the first compression roll 21 and the second compression roll 22 can be adjusted.

[0021] In this embodiment, the pair of first sub-supports 33 are provided on the device frame 30 via first bending cylinders 41. Here, by moving the pair of first sub-supports 33 in the vertical direction via the first bending cylinders 41, both ends of the rotation shaft 25 of the first compression roll 21 can be moved up and down, thereby bending the first compression roll 21 up and down. Similarly, the pair of second sub-supports 34 are provided on the device frame 30 via second bending cylinders 42. Here, by moving the pair of second sub-supports 34 in the vertical direction via the second bending cylinders 42, both ends of the rotation shaft 25 of the second compression roll 22 can be moved up and down, thereby bending the second compression roll 22 up and down. In this way, by bending the first compression roll 21 and the second compression roll 22 up and down, it is possible to adjust the pressure applied to the electrode sheet 5 evenly.

[0022] In this embodiment, the compression roll 20 has a so-called crown shape. Before both ends of the compression roll 20 are induction-heated by an electromagnetic induction generator 60 (described later), the diameter D11 of both ends of the compression roll 20 (here, the first compression roll 21 and the second compression roll 22) is smaller than the diameter D12 of a central portion (typically, the center) of the compression roll 20 in the axial direction D1. Here, both ends of the compression roll 20 refer to both ends in the axial direction D1 of the compression roll 20 that can come into contact with the electrode sheet 5 when compressing the electrode sheet 5. Here, the roll body 26 (e.g., the surface of the roll body 26) of the compression roll 20 comes into contact with the electrode sheet 5, but the rotation shaft 25 does not come into contact with the electrode sheet 5. Therefore, both ends of the compression roll 20 can be rephrased as both ends of the roll body 26 in the axial direction D1. Here, the diameter D11 of both ends of the roll body 26 of the compression roll 20 is smaller than the diameter D12 of the central portion of the compression roll 20. In this embodiment, in a plan view, the line showing the outline extending from the ends of both ends of the compression roll 20 toward the center in the axial direction D1 (in other words, the line showing the outline connecting both ends of the compression roll 20) is a diagonally extending straight line, but may also be a curved line. Also, in this embodiment, both ends of the compression roll 20 are flat, but may also be curved.

[0023] As shown in FIG. 1 , a drive source 50 is connected to the pair of compression rolls 20. The drive source 50 rotates the first compression roll 21 and the second compression roll 22 about a rotation axis 25. The drive source 50 is configured, for example, by a drive motor and gears, but the configuration is not particularly limited. The drive source 50 may be provided separately for the first compression roll 21 and the second compression roll 22, or a common drive source may be provided. Furthermore, the drive source 50 may be connected to only one of the first compression roll 21 and the second compression roll 22. In other words, one of the pair of compression rolls 20 may be a drive roll and the other a driven roll.

[0024] 1, the compression roll apparatus 10 includes an electromagnetic induction generator 60. The electromagnetic induction generator 60 generates electromagnetic induction to inductively heat both ends of the pair of compression rolls 20 (here, the first compression roll 21 and the second compression roll 22). The electromagnetic induction generators 60 are provided spaced apart at both ends of the pair of compression rolls 20 (here, both ends in the axial direction D1 of the roll body 26).

[0025] The configuration of the electromagnetic induction generator 60 is not particularly limited. FIG. 3 is a front view of the compression roll device 10, and is a diagram schematically illustrating the compression roll 20 and the coil 65 of the electromagnetic induction generator 60. FIG. 4 is a side view of the compression roll device 10 as viewed from the axial direction D1, and is a diagram schematically illustrating the compression roll 20 and the coil 65 of the electromagnetic induction generator 60. In this embodiment, as shown in FIG. 4, the electromagnetic induction generator 60 includes the coil 65 and a current generator 70. As shown in FIG. 3, the coil 65 is provided at both ends of the compression roll 20 so as to be spaced apart. Here, as shown in FIG. 1, the coil 65 is disposed outward from both ends of the roll body 26 of the compression roll 20 and around the rotation shaft 25.

[0026] Specifically, the coil 65 includes a coil 65a disposed between the roll body 26 of the first compression roll 21 and one of the first main support parts 31a, a coil 65b disposed between the roll body 26 of the first compression roll 21 and the other of the first main support parts 31b, a coil 65c disposed between the roll body 26 of the second compression roll 22 and one of the second main support parts 32a, and a coil 65d disposed between the roll body 26 of the second compression roll 22 and the other of the second main support parts 32b. A plurality of the coils 65a, 65b, 65c, and 65d are provided so as to surround the rotation shaft 25 in the circumferential direction. In FIG. 1, the coils 65a, 65b, 65c, and 65d are abbreviated to rectangular shapes for ease of viewing. In this embodiment, the coils 65a, 65b, 65c, and 65d have the same configuration. Therefore, in the following, the term coil 65 will be used in a common description of the coils 65a, 65b, 65c, and 65d.

[0027] In this embodiment, as shown in FIG. 3, each coil 65 has a central axis 66. The central axis 66 extends in the axial direction D1. The coil 65 is wound around the central axis 66. Furthermore, as shown in FIG. 4, a plurality of coils 65 wound around the central axis 66 are arranged in the circumferential direction around the rotation shaft 25 of the compression roll 20. The number of coils 65 arranged in the circumferential direction of the rotation shaft 25 is not particularly limited and is determined appropriately depending on the size of the compression roll 20 and the required degree of induction heating. Here, the number of coils 65 arranged in the circumferential direction is eight. In this embodiment, the plurality of coils 65 arranged in the circumferential direction of the rotation shaft 25 are arranged at equal intervals, but the intervals between adjacent coils 65 in the circumferential direction may be different.

[0028] In this embodiment, as shown in FIG. 3, metal members 68 are disposed between both ends of the compression roll 20 and the coil 65. The metal members 68 are, for example, plate-shaped and disk-shaped and inserted into the rotary shaft 25. The type of metal forming the metal members 68 is not particularly limited, but it is preferable that the metal be one that easily conducts heat. For example, the metal members 68 may be formed of a metal that is easily induction-heated, such as stainless steel (e.g., ferritic stainless steel), and that is not too soft (has a predetermined hardness). Specifically, the metal members 68 may be formed of stainless steel (e.g., SUS430).

[0029] The multiple coils 65 arranged along the circumferential direction of the rotating shaft 25 may be attached to and supported by a metal member 68. Note that these coils 65 may also be supported by a member separate from the metal member 68. In this embodiment, the multiple coils 65 and the metal member 68 are configured not to rotate with the rotation of the compression roll 20, but may be configured to rotate together with the rotation of the compression roll 20.

[0030] In this embodiment, as shown in FIG. 4, a current generator 70 is connected to the coils 65 (more specifically, coils 65a, 65b, 65c, and 65d (see FIG. 1) arranged at both ends of each compression roll 20). The current generator 70 applies current to the coils 65. In this embodiment, the current flowing from the current generator 70 to the coils 65 is an AC current. The current applied to the coils 65 from the current generator 70 flows in the direction of arrow A11, as shown in FIG. 3, for example. At this time, a magnetic force (e.g., a magnetic field) is generated in the coil 65 in the direction of arrow A12. This generates a magnetic force (e.g., a magnetic field) in the compression roll 20 in the direction of arrow A13, generating an induced current. The resistance generated by this induced current causes induction heating of both ends of the compression roll 20 (here, the roll bodies 26 of the first compression roll 21 and the second compression roll 22). When the current flowing through coil 65 is an alternating current, for example, a current flows alternately in the direction of arrow A11 and a current flowing in the opposite direction to arrow A11. When a current flowing in the opposite direction to arrow A11 flows through coil 65, a magnetic force is generated in the opposite direction to arrows A12 and A13, and the direction of the induced current is also reversed. In this way, both ends of compression roll 20 can be heated by periodically changing the direction of the induced current.

[0031] As shown in Figure 1, the compression roll device 10 is equipped with a sensor 75. The sensor 75 measures the temperature at both ends of the compression roll 20. The location of the sensor 75 is not particularly limited as long as it can measure the temperature at both ends of the compression roll 20. The sensor 75 is a non-contact sensor with respect to the compression roll 20, but it may also be a contact sensor with respect to the compression roll 20.

[0032] Here, the sensors 75 include a first sensor 75a that measures the temperature of one end of the first compression roll 21 in the axial direction D1 (here, the left end of the roll body 26), a second sensor 75b that measures the temperature of the other end of the first compression roll 21 in the axial direction D1 (here, the right end of the roll body 26), a third sensor 75c that measures the temperature of one end of the second compression roll 22 in the axial direction D1, and a fourth sensor 75d that measures the temperature of the other end of the second compression roll 22 in the axial direction D1. The first sensor 75a and the second sensor 75b are located above the left and right ends of the first compression roll 21, respectively. The third sensor 75c and the fourth sensor 75d are located below the left and right ends of the second compression roll 22, respectively.

[0033] FIG. 5 is a block diagram of the compression roll apparatus 10 according to this embodiment. In this embodiment, as shown in FIG. 5, the compression roll apparatus 10 includes a control device 80. The control device 80 controls the heating of the compression rolls 20 while controlling the degree of compression of the electrode sheet 5 sandwiched between the pair of compression rolls 20. The control device 80 is configured, for example, by a microcontroller. The control device 80 includes a communication interface, a central processing unit (CPU) that executes instructions from a control program, a ROM (read only memory) that stores the program executed by the CPU, a RAM (random access memory) used as a working area for expanding the program, and a storage device such as a memory that stores the program and various data.

[0034] In this embodiment, the control device 80 is electrically and communicatively connected to the main cylinder 40, the first bending cylinder 41, the second bending cylinder 42, the drive source 50, the electromagnetic induction generator 60 (more specifically, the current generator 70), and the sensors 75 (e.g., first sensors 75a to fourth sensors 75d). The control device 80 controls the main cylinder 40, the first bending cylinder 41, the second bending cylinder 42, the drive source 50, the electromagnetic induction generator 60, and the sensors 75. Here, the control device 80 controls the main cylinder 40 to control the vertical movement of the first compression roll 21 and adjust the gap between the first compression roll 21 and the second compression roll 22. The control device 80 controls the first bending cylinder 41 to control the vertical movement of both ends of the first compression roll 21 and adjust the deflection of the first compression roll 21. Furthermore, the control device 80 controls the second bending cylinder 42 to control the vertical movement of both end portions of the second compression roll 22, thereby adjusting the deflection of the second compression roll 22.

[0035] The control device 80 controls the drive source 50 to control the rotation (e.g., rotation speed) of the first compression roll 21 and the second compression roll 22. The control device 80 controls the current generator 70 of the electromagnetic induction generating device 60 to control the amount of current flowing through the coil 65, thereby controlling the degree of induction heating of the pair of compression rolls 20. The control device 80 acquires the temperatures of both ends of the compression roll 20 measured by the sensors 75.

[0036] 5, the control device 80 includes a storage unit 81, a pre-heating unit 83, and a compression control unit 85. The storage unit 81, the pre-heating unit 83, and the compression control unit 85 may be realized by one or more processors or by circuits.

[0037] The configuration of the compression roll device 10 according to this embodiment has been described above. Next, an electrode sheet production method for producing an electrode sheet 5 using the compression roll device 10 according to this embodiment will be described with reference to the flowchart in FIG. 6. In the electrode sheet production method, the compression roll device 10 is used, and in a state in which electromagnetic induction is generated by an electromagnetic induction generator 60 to induction-heat both ends of the compression rolls 20, the electrode sheet 5 is sandwiched between a pair of compression rolls 20 and compressed, thereby producing the electrode sheet 5. Here, the electrode sheet 5 is produced by compressing the electrode sheet 5 in the width direction (for example, the vertical direction) while heating both ends of the pair of compression rolls 20 that sandwich the electrode sheet 5.

[0038] First, in preparation step S101 of FIG. 6, an electrode sheet 5 as shown in FIG. 2 is prepared. Here, a sheet-like current collector 6 is prepared. Next, an electrode active material and optional materials (e.g., binder, conductive material, etc.) are dispersed in an appropriate solvent to prepare a slurry composition. An appropriate amount of this composition is applied to the surface of the current collector 6 and dried. This forms an electrode active material layer 7 on the surface of the current collector 6, and an electrode sheet 5 is prepared. In preparation step S101, the prepared electrode sheet 5 is sandwiched between a pair of compression rolls 20 (here, between a first compression roll 21 and a second compression roll 22), as shown in FIG. 1.

[0039] Next, in a pre-heating step S103 in FIG. 6, before compressing the electrode sheet 5 with the pair of compression rolls 20, both end portions of the pair of compression rolls 20 (here, the first compression roll 21 and the second compression roll 22) are heated. The pre-heating step S103 is embodied by the pre-heating unit 83 of the control device 80 in FIG. 5. The pre-heating unit 83 heats both end portions of the pair of compression rolls 20 using the electromagnetic induction generator 60 so that the temperatures of both end portions of the pair of compression rolls 20 become a predetermined reference temperature T1 (see FIG. 5). Here, as shown in FIG. 5, the reference temperature T1 is stored in advance in the memory unit 81.

[0040] In this embodiment, the preheating unit 83 acquires the temperatures of both ends of the compression roll 20 from the sensor 75 at predetermined time intervals. The preheating unit 83 then determines whether the temperature acquired from the sensor 75 is equal to or greater than a reference temperature T1. If the temperature is less than the reference temperature T1, the preheating unit 83 continues heating both ends of the compression roll 20. During heating, the preheating unit 83 controls the current generator 70 to pass current through the coil 65. For example, as shown in FIG. 3 , when current flows through the coil 65 in the direction of arrow A11, a magnetic force is generated in the coil 65 in the direction of arrow A12. As a result, a magnetic force is generated at both ends of the compression roll 20 in the direction of arrow A13, generating an induced current. The resistance generated by the induced current causes induction heating of both ends of the compression roll 20. When the pre-heating unit 83 determines that the temperature of both ends of the compression roll 20 obtained from the sensor 75 is equal to or higher than the reference temperature T1, it stops the current generator 70, for example, to stop heating of both ends of the compression roll 20. However, when the temperature of both ends of the compression roll 20 is equal to or higher than the reference temperature T1, the pre-heating unit 83 may control the current generator 70 to pass a current through the coil 65 to the extent that the temperature of both ends of the compression roll 20 does not drop.

[0041] In this embodiment, when both ends of the compression roll 20 are heated, the both ends expand, and the diameter D11 shown in Figure 1 increases. When both ends of the compression roll 20 are heated until the temperatures of the both ends reach or exceed the reference temperature T1, the diameter D11 of the both ends becomes approximately the same as the diameter D12 (see Figure 1) of the central portion of the compression roll 20 in the axial direction D1. In other words, when both ends of the compression roll 20 are heated until the temperatures of the both ends reach or exceed the reference temperature T1, the both ends expand, and the line extending in the axial direction D1 that indicates the outline of the compression roll 20 can become a straight line parallel to the axial direction D1.

[0042] In this embodiment, the amount of current flowing through coils 65a, 65b, 65c, and 65d can be individually controlled. When the temperature of either the left or right end of the first compression roll 21 or the left or right end of the second compression roll 22 reaches or exceeds the reference temperature T1, heating of the corresponding end of the compression roll 20 is stopped. When the temperatures of the left and right ends of the first compression roll 21 and the left and right ends of the second compression roll 22 reach or exceed the reference temperature T1, the preheating step S103 in FIG. 6 is terminated.

[0043] After the temperatures at both ends of each compression roll 20 are raised to or above the reference temperature T1, the compression step S105 shown in FIG. 6 is performed. The compression step S105 is implemented by the compression control unit 85 of the control device 80 shown in FIG. 5. After control by the preheating unit 83, the compression control unit 85 compresses the electrode sheet 5 sandwiched between the pair of compression rolls 20 while controlling the electromagnetic induction generator 60 so that the temperatures at both ends of the compression roll 20 are within a predetermined range R1 (see FIG. 5). Here, the predetermined range R1 is a range based on the reference temperature T1 and is a predetermined range. For example, the predetermined range R1 is set so that the reference temperature T1 is located between the upper and lower limits of the predetermined range R1 (as an example, the intermediate value between the upper and lower limits of the predetermined range R1 is the reference temperature T1). Note that, as shown in FIG. 5, the predetermined range R1 is pre-stored in the memory unit 81.

[0044] 1 , the compression control unit 85 controls the drive source 50 to rotate the first compression roll 21 and the second compression roll 22 around the rotation axis 25. As a result, the electrode sheet 5 sandwiched between the pair of compression rolls 20 is compressed while being heated by the compression rolls 20, and is discharged from between the pair of compression rolls 20.

[0045] In this embodiment, the compression control unit 85 may or may not pass current from the current generator 70 to the coil 65 when the temperature of both ends of the compression roll 20 is within a predetermined range R1. The compression control unit 85 controls the temperature of both ends of the compression roll 20 to be within the predetermined range R1 by adjusting the amount of current passed through the coil 65. For example, the compression control unit 85 determines whether the temperature of both ends of the compression roll 20 obtained from the sensor 75 is within the predetermined range R1. Here, if the temperature of both ends of the compression roll 20 is lower than the lower limit of the predetermined range R1, the compression control unit 85 controls the current generator 70 to increase the amount of current passed through the coil 65 located at the corresponding end of the compression roll 20. On the other hand, if the temperature of both ends of the compression roll 20 is higher than the upper limit of the predetermined range R1, the compression control unit 85 controls the current generator 70 to decrease (e.g., to zero) the amount of current passed through the coil 65 located at the corresponding end of the compression roll 20. In this way, the electrode sheet 5 sandwiched between the pair of compression rolls 20 can be compressed while being heated.

[0046] As described above, in this embodiment, as shown in FIG. 1 , the compression roll device 10 includes a pair of compression rolls 20 that sandwich and compress the electrode sheet 5, and an electromagnetic induction generator 60 that is spaced apart at both ends of the compression rolls 20 in the axial direction D1 and generates electromagnetic induction to inductively heat both ends of the compression rolls 20. In this manner, both ends of the pair of compression rolls 20 can be heated by the induction heating generated by the electromagnetic induction generator 60. By heating both ends of the compression rolls 20 by induction heating in this manner, both ends of the compression rolls 20 can be heated with a simpler configuration than conventional methods. In the electrode sheet production method according to this embodiment, the use of the compression roll device 10 allows the electrode sheet 5 to be produced in a sufficiently heated and compressed state.

[0047] In this embodiment, before the end portions of the compression roll 20 are induction-heated by the electromagnetic induction generator 60, the diameter D11 of each end portion of the compression roll 20 is smaller than the diameter D12 of the central portion of the compression roll 20 in the axial direction D1. Here, when the end portions of the compression roll 20 are heated by the electromagnetic induction generator 60, the end portions expand, increasing the diameter D11 of each end portion of the compression roll 20. Therefore, by heating the end portions of the compression roll 20, the diameter D11 of each end portion and the diameter D12 of the central portion of the compression roll 20 in the axial direction D1 can be made substantially the same. Therefore, when the electrode sheet 5 is sandwiched between a pair of heated compression rolls 20 and compressed, the electrode sheet 5 can be easily compressed evenly.

[0048] In this embodiment, as shown in FIG. 1 , the compression roll 20 includes a rotation shaft 25 extending in the axial direction D1. As shown in FIG. 3 , the electromagnetic induction generator 60 includes a coil 65 wound around a central axis 66 extending in the axial direction D1. As shown in FIG. 4 , a plurality of coils 65 are arranged around the rotation shaft 25 of the compression roll 20 in the circumferential direction. By arranging a plurality of coils 65 wound around the central axis 66 around the rotation shaft 25 in this manner, it is possible to easily generate an induced current based on a magnetic force generated by a current flowing through the coil 65. This facilitates induction heating, making it possible to easily heat both ends of the compression roll 20.

[0049] In this embodiment, as shown in Fig. 3, metal members 68 are disposed between both end portions of the compression roll 20 and the coil 65. This allows heat to be easily transferred from the coil 65 to both end portions of the compression roll 20 through the metal members 68. Therefore, both end portions of the compression roll 20 can be efficiently heated.

[0050] In this embodiment, as shown in FIG. 5 , the compression roll device 10 includes a sensor 75 that measures the temperature of both ends of the compression roll 20 and a control device 80 connected to the electromagnetic induction generator 60. The control device 80 includes a preheating unit 83 and a compression control unit 85. In a preheating step S103 of FIG. 6 , the preheating unit 83 heats both ends of the compression roll 20 using the electromagnetic induction generator 60 so that the temperature of both ends of the compression roll 20 reaches a predetermined reference temperature T1 (see FIG. 5 ). After control by the preheating unit 83, in a compression step S105 of FIG. 6 , the compression control unit 85 controls the electromagnetic induction generator 60 so that the temperature of both ends of the compression roll 20 falls within a predetermined range R1 (see FIG. 5 ) based on the reference temperature T1 while compressing the electrode sheet 5 sandwiched between the pair of compression rolls 20. This allows the temperature of both ends of the compression roll 20 to be equal to or higher than the reference temperature T1 before the electrode sheet 5 is compressed by the pair of compression rolls 20. Therefore, the electrode sheet 5 is compressed in a state where the temperatures at both ends of the compression roll 20 are equal to or higher than the reference temperature T1, so that the electrode sheet 5 can be compressed while being sufficiently heated.

[0051] 5, the electromagnetic induction generator 60 includes a current generator 70 that applies current to a coil 65. The compression control unit 85 adjusts the amount of current applied to the coil 65 to control the temperature of both ends of the compression roll 20 to fall within a predetermined range R1. In this way, adjusting the amount of current applied to the coil 65 adjusts the degree of induction heating generated in the compression roll 20, making it easy to control the temperature of both ends of the compression roll 20 to fall within the predetermined range R1.

[0052] In this embodiment, as shown in FIGS. 3 and 4, multiple coils 65 wound around a central axis 66 are arranged along the circumferential direction of the rotation shaft 25 of the compression roll 20. However, the coil configuration disclosed herein is not limited to the coil 65 wound around the central axis 66. FIGS. 7 and 8 are views corresponding to FIGS. 3 and 4, respectively, showing a compression roll device 10A according to a modified example. For example, as shown in FIGS. 7 and 8, the coil disclosed herein may be a coil 65A wound around the rotation shaft 25 of the compression roll 20. In other words, the coil 65A may be wound spirally in the circumferential direction of the rotation shaft 25. Even with such a coil 65A, the same effects as those of the above embodiment can be obtained.

[0053] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.

[0054] As described above, this specification includes the disclosures set forth in the following sections. Section 1: a pair of compression rolls that sandwich and compress the electrode sheet; an electromagnetic induction generator provided at each end of the compression roll in the axial direction and spaced apart from each other, for generating electromagnetic induction to inductively heat the ends of the compression roll; A compression roll device comprising:

[0055] Section 2: Item 1. The compression roll device according to item 1, wherein the diameters of the both ends of the compression roll are smaller than the diameter of the axial center portion of the compression roll before the both ends of the compression roll are induction heated by the electromagnetic induction generator.

[0056] Section 3: The compression roll has a rotation axis extending in the axial direction, the electromagnetic induction generator includes a coil wound around a central axis extending in the axial direction, Item 3. The compression roll device according to item 1 or 2, wherein a plurality of the coils are arranged along the circumferential direction around the rotation axis of the compression roll.

[0057] Section 4: Item 4. The compression roll device according to item 3, wherein a metal member is disposed between the both ends of the compression roll and the coil.

[0058] Section 5: sensors for measuring the temperatures at both ends of the compression roll; a control device connected to the electromagnetic induction generator; Equipped with The control device a preheating unit that heats both end portions of the compression roll by the electromagnetic induction generator so that the temperatures of the both end portions reach a predetermined reference temperature; a compression control unit that, after control by the preheating unit, controls the electromagnetic induction generator while compressing the electrode sheet sandwiched between the pair of compression rolls so that the temperatures of the both end portions of the compression rolls are within a predetermined range based on the reference temperature; and A compression roll device according to any one of items 1 to 4, comprising:

[0059] Item 6: The compression roll has a rotation axis extending in the axial direction, The electromagnetic induction generating device is a coil wound around a central axis extending in the axial direction; a current generator for passing a current through the coil; Equipped with Item 6. The compression roll device according to item 5, wherein the compression control unit controls the temperature of the both ends of the compression roll to be within the predetermined range by adjusting the amount of current flowing through the coil.

[0060] Section 7: Item 7. An electrode sheet manufacturing method using a compression roll device according to any one of Items 1 to 6, wherein the electrode sheet is sandwiched between a pair of compression rolls and compressed in a state where the electromagnetic induction is generated by the electromagnetic induction generator to inductively heat both end portions of the compression roll, thereby manufacturing the electrode sheet. [Explanation of symbols]

[0061] 5 Electrode sheet 10 Compression Roll Device 20 pairs of compression rolls 21 First compression roll 22 Second compression roll 25 Rotation axis 26 Roll body 60 Electromagnetic Induction Generator 65 coils 68 Metallic parts 70 Current Generator 75 sensors 80 Control device 83 Pre-heating section 85 Compression control section D1 Axial direction

Claims

1. a pair of compression rolls that sandwich and compress the electrode sheet; Two electromagnetic induction generators are provided at both ends of the compression roll in the axial direction, spaced apart from each other, and generate electromagnetic induction to inductively heat both ends of the compression roll; Equipped with The compression roll has a rotation axis extending in the axial direction, the electromagnetic induction generator includes a coil wound around a central axis extending in the axial direction, A compression roll device, wherein a plurality of the coils are arranged along a circumferential direction around the rotation axis of the compression roll.

2. 2. The compression roll apparatus of claim 1, wherein the diameters of the end portions of the compression roll are smaller than the diameter of the axial central portion of the compression roll before the end portions of the compression roll are inductively heated by the electromagnetic induction generator.

3. 2. The compression roll apparatus of claim 1, wherein a metal member is disposed between the ends of the compression roll and the coil.

4. A pair of compression rolls that sandwich and compress the electrode sheet; Two electromagnetic induction generators are provided at both ends of the compression roll in the axial direction, spaced apart from each other, and generate electromagnetic induction to inductively heat both ends of the compression roll; sensors for measuring the temperatures at both ends of the compression roll; a control device connected to the electromagnetic induction generator; Equipped with The control device a preheating unit that heats both end portions of the compression roll by the electromagnetic induction generator so that the temperatures of the both end portions reach a predetermined reference temperature; a compression control unit that, after control by the preheating unit, controls the electromagnetic induction generator while compressing the electrode sheet sandwiched between the pair of compression rolls so that the temperatures of the both end portions of the compression rolls are within a predetermined range based on the reference temperature; and Equipped with The compression roll has a rotation axis extending in the axial direction, The electromagnetic induction generating device is a coil wound around a central axis extending in the axial direction; a current generator for passing a current through the coil; Equipped with The compression control unit controls the temperature of the both ends of the compression roll to be within the predetermined range by adjusting the amount of current flowing through the coil.

5. 5. A method for producing an electrode sheet, comprising: using a compression roll device according to claim 1; generating electromagnetic induction using the electromagnetic induction generating device to inductively heat both end portions of the compression roll; and sandwiching the electrode sheet between a pair of the compression rolls and compressing the electrode sheet to produce the electrode sheet.

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