Compression roll device and method for manufacturing electrode sheet

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 that compresses 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 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 core extending in the axial direction of the roller body and an induction coil wound around the outer peripheral surface of the cylindrical core. The cooling mechanism is provided around the induction coil in the roller body 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 passage within the roller body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-127326 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the heat-generating roller device disclosed in JP 2022-127326 A, an induction heat generating mechanism for heating and a cooling mechanism for cooling are provided inside the roller body, which makes the heat-generating roller device complex in configuration. [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 spaced apart at both axial ends of the compression roll and generates electromagnetic induction to inductively heat both ends of the compression roll.

[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 in the past. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a front view showing a compression roll device according to the embodiment; [Diagram 2] FIG. 2 is a cross-sectional view illustrating an example of an electrode sheet. [Diagram 3] FIG. 2 is a front view showing a compression roll device according to an embodiment, and is a diagram 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 illustrating the compression roll and the coil of the electromagnetic induction generator. [Diagram 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] 4 is a view corresponding to FIG. 3 and showing a compression roll device according to a modified example. FIG. [Figure 8] 4 and shows a compression roll device according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the technology disclosed herein will be described 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. Each drawing is drawn typically and does not necessarily faithfully reflect an actual embodiment. Furthermore, the same reference numerals are appropriately used for components and parts that perform the same function, and duplicated explanations are appropriately omitted.

[0010] FIG. 1 is a front view showing a compression roll device 10 according to the present embodiment. As shown in FIG. 1, the compression roll device 10 according to the present embodiment is a device that compresses an electrode sheet 5. The type of the electrode sheet 5 is not particularly limited. For example, the electrode sheet 5 is used in a so-called secondary battery. The secondary battery here refers to 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 into which an electrolyte is injected.

[0011] FIG. 2 is a cross-sectional view showing an example of the electrode sheet 5. As shown in FIG. 2, the electrode sheet 5 has 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 of FIG. 2, the electrode active material layer 7 is formed on both sides of the current collector 6, but 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 electrical conductivity, and may be formed of a metal material 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, for example, 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 electrical conductivity, and may be formed of, for example, copper (copper foil) or an alloy mainly composed of copper. In the electrode active material layer 7 for the negative electrode, so-called negative electrode active materials, such as particulate (or spherical or flake) carbon materials having at least a graphite structure (e.g., a layered structure) in part, lithium transition metal composite oxides, and lithium transition metal composite nitrides, 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 as described above to compress and 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 a first compression roll 21, and the other compression roll 20 is also referred to as a second compression roll 22. In this embodiment, the pair of compression rolls 20 are arranged vertically. Here, the first compression roll 21 is arranged above the second compression roll 22. In this embodiment, the electrode sheet 5 is compressed by rotating the first compression roll 21 and the second compression roll 22 while being arranged 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 the first compression roll 21 and the second compression roll 22 are described 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 determined for the convenience of explanation and does not particularly limit the present embodiment and 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 the roll body 26 to one end side in the axial direction D1, and also protrudes from the roll body 26 to the other end side 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 of the first main support parts 31a rotatably supports one end (here, the left end) of the rotating 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 rotating shaft 25 of the first compression roll 21. Here, the one of the first main support parts 31a is provided with a first left main bearing 31c, and the rotating shaft 25 of the first compression roll 21 is rotatably inserted into the first left main bearing 31c. A first right main bearing 31d is provided on the other first main support portion 31b, and the rotating 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, outside the first compression roll 21 relative 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 rotating 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 rotating shaft 25 of the first compression roll 21, and the other first sub-support part 33b rotatably supports the other end of the rotating shaft 25 of the first compression roll 21. In detail, one first sub-support part 33a is provided with a first left sub-bearing 33c, and the rotating 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 rotating 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 of the second main support parts 32a rotatably supports one end (here, the left end) of the rotating shaft 25 of the second compression roll 22, and the other of the second main support parts 32b rotatably supports the other end (here, the right end) of the rotating shaft 25 of the second compression roll 22. More specifically, the one of the second main support parts 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 of the second main support parts 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-support parts 34 are disposed below the pair of first sub-support parts 33. The pair of second sub-support parts 34 are disposed outside the pair of second main support parts 32 of the second compression roll 22, and are arranged in line with the pair of second main support parts 32 in the axial direction D1. The pair of second sub-support parts 34 rotatably support a portion of the second compression roll 22 that is closer to the end of the rotating 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 rotating shaft 25 of the second compression roll 22, and the other second sub-support part 34b rotatably supports the other end of the rotating shaft 25 of the second compression roll 22. In detail, one second sub-support part 34a is provided with a second left sub-bearing 34c, and the rotating 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 rotating 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 31, the second main support 32, the first sub support 33, and the second sub support 34 are supported by the device frame 30. Here, the pair of second main support 32 is disposed at a fixed position relative to the device frame 30. The first main support 31, the first sub support 33, and the second sub support 34 are configured to be movable in the vertical direction relative to the device frame 30. Here, the pair of first main support 31 is provided on the device frame 30 via the main cylinder 40. Therefore, the pair of first main support 31 and the first compression roll 21 move in the vertical direction relative to the device frame 30 via the main cylinder 40, thereby adjusting the interval between the first compression roll 21 and the second compression roll 22. This allows the interval between the first compression roll 21 and the second compression roll 22 to be adjusted according to 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 the first bend cylinder 41. Here, by moving the pair of first sub-supports 33 in the vertical direction via the first bend cylinder 41, both ends of the rotating shaft 25 of the first compression roll 21 can be moved up and down to bend the first compression roll 21 up and down. Similarly, the pair of second sub-supports 34 are provided on the device frame 30 via the second bend cylinder 42. Here, by moving the pair of second sub-supports 34 in the vertical direction via the second bend cylinder 42, both ends of the rotating shaft 25 of the second compression roll 22 can be moved up and down to bend 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 so that pressure is applied evenly to the electrode sheet 5.

[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 diameters D11 of both ends of the compression roll 20 (here, the first compression roll 21 and the second compression roll 22) are smaller than the diameter D12 of the 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 portion of the compression roll 20 that can be contacted with the electrode sheet 5 when compressing the electrode sheet 5. Here, the roll body 26 (for example, the surface of the roll body 26) of the compression roll 20 contacts the electrode sheet 5, but the rotating shaft 25 does not contact 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 diameters D11 of both ends of the roll body 26 of the compression roll 20 are 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 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 straight line extending obliquely, but may be a curved line. Also, in this embodiment, both ends of the compression roll 20 are flat, but may be curved.

[0023] As shown in FIG. 1, a driving source 50 is connected to the pair of compression rolls 20. The driving source 50 rotates the first compression roll 21 and the second compression roll 22 around a rotation shaft 25. The driving source 50 is, for example, composed of a driving motor and a gear, but the configuration is not particularly limited. The driving source 50 may be provided separately for the first compression roll 21 and the second compression roll 22, or may be a common source. The driving source 50 may be connected to only one of the first compression roll 21 and the second compression roll 22. That is, one of the pair of compression rolls 20 may be a driving roll, and the other may be a driven roll.

[0024] In this embodiment, as shown in Fig. 1, the compression roll apparatus 10 includes an electromagnetic induction generator 60. The electromagnetic induction generator 60 is a device that 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 from each other 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 showing the compression roll device 10, and is a diagram showing 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 seen from the axial direction D1, and is a diagram showing 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 has a coil 65 and a current generator 70. As shown in FIG. 3, the coil 65 is provided so as to be spaced apart from both ends of the compression roll 20. Here, as shown in FIG. 1, the coil 65 is disposed outside both ends of the roll body 26 of the compression roll 20 and around the rotation shaft 25.

[0026] In detail, the coil 65 includes a coil 65a arranged between the roll body 26 of the first compression roll 21 and one of the first main support parts 31a, a coil 65b arranged between the roll body 26 of the first compression roll 21 and the other of the first main support parts 31b, a coil 65c arranged between the roll body 26 of the second compression roll 22 and one of the second main support parts 32a, and a coil 65d arranged between the roll body 26 of the second compression roll 22 and the other of the second main support parts 32b. Note that the coils 65a, 65b, 65c, and 65d are each provided in a plurality of coils so as to surround the rotating shaft 25 in the circumferential direction. Note that in FIG. 1, the coils 65a, 65b, 65c, and 65d are abbreviated to a square shape in order to make the drawing easier to see. In this embodiment, the coils 65a, 65b, 65c, and 65d have the same configuration. Therefore, in the following, in the common description of coils 65a, 65b, 65c, and 65d, the term coil 65 will be used.

[0027] In this embodiment, as shown in FIG. 3, one 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. Also, as shown in FIG. 4, a plurality of coils 65 wound around the central axis 66 are arranged along the circumferential direction around the rotating shaft 25 of the compression roll 20. The number of coils 65 arranged in the circumferential direction of the rotating shaft 25 is not particularly limited, and is appropriately determined according to the size of the compression roll 20 and the degree of induction heating required. 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 rotating 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, a metal member 68 is disposed between both ends of the compression roll 20 and the coil 65. The metal member 68 is, for example, plate-shaped and disk-shaped and inserted into the rotating shaft 25. The type of metal forming the metal member 68 is not particularly limited, but it is preferable that the metal member 68 is made of a metal that easily transmits heat. For example, the metal member 68 may be made of a metal that is easily induction-heated, such as stainless steel (e.g., ferritic stainless steel), and is not too soft (having a predetermined hardness). Specifically, the metal member 68 may be made 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 be supported by a member other than 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 coil 65 (more specifically, the coils 65a, 65b, 65c, and 65d (see FIG. 1) arranged at both ends of each compression roll 20). The current generator 70 applies a current to the coil 65. Here, the current flowing from the current generator 70 to the coil 65 is an AC current. The current applied from the current generator 70 to the coil 65 flows in the direction of the arrow A11, as shown in FIG. 3, for example. At this time, a magnetic force (e.g., a magnetic field) in the direction of the arrow A12 is generated in the coil 65. As a result, a magnetic force (e.g., a magnetic field) is generated in the compression roll 20 in the direction of the arrow A13, and an induced current is generated. The resistance generated when this induced current is generated causes induction heating of both ends of the compression roll 20 (here, the roll body 26 of each of the first compression roll 21 and the second compression roll 22). When the current flowing through the coil 65 is an alternating current, for example, a current in the direction of the arrow A11 and a current in the opposite direction to the arrow A11 flow alternately. When a current in the opposite direction to the arrow A11 flows through the coil 65, a magnetic force in the opposite direction to the arrows A12 and A13 is generated, and the direction of the induced current is also reversed. In this way, both ends of the compression roll 20 can be heated while periodically changing the direction of the induced current.

[0031] As shown in Fig. 1, the compression roll device 10 includes 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 may be a contact sensor with respect to the compression roll 20.

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

[0033] FIG. 5 is a block diagram of the compression roll device 10 according to this embodiment. In this embodiment, as shown in FIG. 5, the compression roll device 10 includes a control device 80. The control device 80 is a device that 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 by, for example, a microcontroller. The control device 80 includes a communication interface, a central processing unit (CPU) that executes instructions of 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 above program and various data.

[0034] In this embodiment, the control device 80 is electrically and communicably connected to the main cylinder 40, the first bending cylinder 41, the second bending cylinder 42, the driving source 50, the electromagnetic induction generator 60 (more specifically, the current generator 70), and the sensor 75 (for example, the first sensor 75a to the fourth sensor 75d). The control device 80 controls the main cylinder 40, the first bending cylinder 41, the second bending cylinder 42, the driving source 50, the electromagnetic induction generator 60, and the sensor 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 and adjust 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 may be realized by a circuit.

[0037] The configuration of the compression roll device 10 according to this embodiment has been described above. Next, an electrode sheet preparation method for preparing the electrode sheet 5 using the compression roll device 10 according to this embodiment will be described with reference to the flowchart of FIG. 6. In the electrode sheet preparation method, the compression roll device 10 is used, and in a state in which electromagnetic induction is generated by the electromagnetic induction generator 60 to inductively heat both ends of the compression roll 20, the electrode sheet 5 is sandwiched between a pair of compression rolls 20 and compressed to prepare the electrode sheet 5. Here, the electrode sheet 5 is prepared 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 sandwiching the electrode sheet 5.

[0038] First, in the preparation step S101 in 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 materials used as necessary (e.g., binder, conductive material, etc.) are dispersed in an appropriate solvent to prepare a slurry-like composition. An appropriate amount of this composition is applied to the surface of the current collector 6 and dried. As a result, an electrode active material layer 7 is formed on the surface of the current collector 6, and an electrode sheet 5 is prepared. In the 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 ends 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 a pre-heating unit 83 of a control device 80 in Fig. 5. The pre-heating unit 83 heats both ends of the pair of compression rolls 20 by an electromagnetic induction generator 60 so that the temperatures of both ends 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 a storage unit 81.

[0040] In this embodiment, the pre-heating unit 83 obtains the temperature of both ends of the compression roll 20 from the sensor 75 at every predetermined reference time. Then, the pre-heating unit 83 judges whether the temperature obtained from the sensor 75 is equal to or higher than the reference temperature T1, and continues heating both ends of the compression roll 20 when the temperature is lower than the reference temperature T1. Here, during heating, the pre-heating unit 83 controls the current generator 70 so that a current flows from the current generator 70 to the coil 65. For example, as shown in FIG. 3, when a current flows in the direction of the arrow A11 in the coil 65, a magnetic force is generated in the coil 65 in the direction of the arrow A12. As a result, a magnetic force is generated in the direction of the arrow A13 at both ends of the compression roll 20, and an induced current is generated. The resistance generated when the induced current is generated causes induction heating of both ends of the compression roll 20. When the pre-heating unit 83 determines that the temperatures at both ends of the compression roll 20 obtained from the sensor 75 are equal to or higher than the reference temperature T1, it stops the current generator 70, for example, to stop the heating of both ends of the compression roll 20. However, when the temperatures at both ends of the compression roll 20 are 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 temperatures at both ends of the compression roll 20 do not decrease.

[0041] In this embodiment, when both ends of the compression roll 20 are heated, the both ends expand, and the diameter D11 shown in Fig. 1 becomes larger. When both ends of the compression roll 20 are heated until the temperature of the both ends becomes equal to or higher than the reference temperature T1, the diameter D11 of the both ends becomes substantially the same as the diameter D12 (see Fig. 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 temperature of the both ends becomes equal to or higher than the reference temperature T1, the both ends expand, and the line extending in the axial direction D1 showing the outline of the compression roll 20 may become a straight line parallel to the axial direction D1.

[0042] In this embodiment, the amount of current flowing through the coils 65a, 65b, 65c, and 65d can be individually controlled. When the temperature of any of the left and right ends of the first compression roll 21 and the left and right ends of the second compression roll 22 becomes equal to or higher than 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 become equal to or higher than the reference temperature T1, the pre-heating step S103 in FIG. 6 is terminated.

[0043] In this way, after the temperature at both ends of each compression roll 20 is made equal to or higher than the reference temperature T1, the compression step S105 in FIG. 6 is performed. The compression step S105 is embodied by the compression control unit 85 of the control device 80 in FIG. 5. The compression control unit 85 controls the electromagnetic induction generator 60 so that the temperature at both ends of the compression roll 20 is within a predetermined range R1 (see FIG. 5) while compressing the electrode sheet 5 sandwiched between the pair of compression rolls 20 after the control by the pre-heating unit 83. Here, the predetermined range R1 is a range based on the reference temperature T1, and is a range that is determined in advance. For example, the predetermined range R1 is set so that the reference temperature T1 is located between the upper limit value and the lower limit value of the predetermined range R1 (as an example, the intermediate value between the upper limit value and the lower limit value of the predetermined range R1 becomes the reference temperature T1). As shown in FIG. 5, the predetermined range R1 is stored in advance in the storage 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 about 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, when the temperature of both ends of the compression roll 20 is within a predetermined range R1, the compression control unit 85 may or may not pass a current from the current generator 70 to the coil 65. 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 acquired from the sensor 75 is within the predetermined range R1. Here, when 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 flowing through the coil 65 arranged at the corresponding end of the compression roll 20. On the other hand, when 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 reduce (for example, to zero) the amount of current flowing through the coil 65 arranged at the corresponding end of the compression roll 20. In this manner, 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 provided at both ends of the compression roll 20 in the axial direction D1 and generates electromagnetic induction to inductively heat both ends of the compression roll 20. In this way, 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 roll 20 by induction heating in this way, both ends of the compression roll 20 can be heated with a simpler configuration than in the past. In the electrode sheet production method according to this embodiment, the compression roll device 10 is used to produce the electrode sheet 5 in a sufficiently heated and compressed state.

[0047] In this embodiment, before both ends of the compression roll 20 are induction-heated by the electromagnetic induction generator 60, the diameter D11 of both ends 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 both ends of the compression roll 20 are heated by the electromagnetic induction generator 60, the both ends expand, and the diameter D11 of both ends of the compression roll 20 becomes larger. Therefore, by heating both ends of the compression roll 20, the diameter D11 of both ends 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 compression rolls 20 in a heated state 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 rotating 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 along the circumferential direction around the rotating shaft 25 of the compression roll 20. In this way, by arranging a plurality of coils 65 wound around the central axis 66 along the circumferential direction of the rotating shaft 25, it is possible to easily generate an induced current based on a magnetic force generated by a current flowing through the coil 65. This makes it easier to perform induction heating, and therefore makes it easier to heat both ends of the compression roll 20.

[0049] 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. This allows heat to be easily transferred from the coil 65 to both ends of the compression roll 20 through the metal members 68. Therefore, both ends 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 for measuring 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 pre-heating unit 83 and a compression control unit 85. In the pre-heating step S103 of FIG. 6, the pre-heating unit 83 heats both ends of the compression roll 20 by the electromagnetic induction generator 60 so that the temperature of both ends of the compression roll 20 becomes a predetermined reference temperature T1 (see FIG. 5). After the control by the pre-heating unit 83, in the 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 becomes 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 makes it possible to make the temperature of both ends of the compression roll 20 equal to or higher than the reference temperature T1 before the electrode sheet 5 is compressed by the pair of compression rolls 20. Therefore, since the electrode sheet 5 is compressed in a state in which the temperatures at both ends of the compression roll 20 are equal to or higher than the reference temperature T1, the electrode sheet 5 can be compressed while being sufficiently heated.

[0051] 5, the electromagnetic induction generator 60 includes a current generator 70 that passes a current through a coil 65. The compression control unit 85 adjusts the amount of current passed through the coil 65 to control the temperature at both ends of the compression roll 20 to be within a predetermined range R1. In this way, by adjusting the amount of current passed through the coil 65, the degree of induction heating generated in the compression roll 20 can be adjusted, and therefore it is easy to control the temperature at both ends of the compression roll 20 to be within the predetermined range R1.

[0052] In this embodiment, as shown in Figs. 3 and 4, a plurality of coils 65 wound around a central axis 66 are arranged along the circumferential direction of the rotating shaft 25 of the compression roll 20. However, the configuration of the coil 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 rotating shaft 25 of the compression roll 20. That is, the coil 65A may be wound in a spiral shape in the circumferential direction of the rotating 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 or each process described herein can be omitted or combined as appropriate, unless a particular problem occurs.

[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 generating device is provided at both ends of the compression roll in the axial direction and spaced apart from each other, and generates electromagnetic induction to inductively heat both ends of the compression roll; A compression roll device comprising:

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

[0056] Section 3: The compression roll has a rotation axis extending in the axial direction, The electromagnetic induction generating device includes a coil wound around a central axis extending in the axial direction, 3. The compression roll device according to item 1 or 2, wherein a plurality of the coils are arranged along a 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 includes: A pre-heating unit that heats both ends of the compression roll by the electromagnetic induction generator so that the temperatures of both ends of the compression roll become a predetermined reference temperature; a compression control unit that controls the electromagnetic induction generator so that the temperature of both ends of the compression rolls falls within a predetermined range based on the reference temperature while compressing the electrode sheet sandwiched between the pair of compression rolls after the control by the pre-heating unit; 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 temperatures of 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. A method for producing an electrode sheet, comprising: using the compression roll device according to any one of Items 1 to 6; generating electromagnetic induction using the electromagnetic induction generator to inductively heat both ends of the compression roll; and compressing the electrode sheet between a pair of the compression rolls to produce the electrode sheet. [Explanation of symbols]

[0061] 5 Electrode sheet 10 Compression roll device 20 Pair of compression rolls 21 First compression roll 22 Second compression roll 25 Rotational Axis 26 Roll body 60 Electromagnetic Induction Generator 65 Coil 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; An electromagnetic induction generating device is provided at both ends of the compression roll in the axial direction and spaced apart from each other, and generates electromagnetic induction to inductively heat both ends of the compression roll; A compression roll device comprising:

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

3. The compression roll has a rotation axis extending in the axial direction, The electromagnetic induction generating device includes a coil wound around a central axis extending in the axial direction, The compression roll device according to claim 1 , wherein the coils are arranged in a circumferential direction around the rotation axis of the compression roll.

4. 4. The compression roll apparatus of claim 3, further comprising a metal member disposed between said ends of said compression roll and said coil.

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 includes: A pre-heating unit that heats both ends of the compression roll by the electromagnetic induction generator so that the temperatures of both ends of the compression roll become a predetermined reference temperature; a compression control unit that controls the electromagnetic induction generator so that the temperature of both ends of the compression rolls falls within a predetermined range based on the reference temperature while compressing the electrode sheet sandwiched between the pair of compression rolls after the control by the pre-heating unit; and 10. The compression roll apparatus of claim 1, comprising:

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 The compression roll device according to claim 5 , wherein the compression control section controls the temperatures of the both ends of the compression roll to be within the predetermined range by adjusting an amount of current flowing through the coil.

7. 7. A method for producing an electrode sheet, comprising: using a compression roll device according to any one of claims 1 to 6; generating electromagnetic induction using the electromagnetic induction generating device to inductively heat both ends of the compression roll; and compressing the electrode sheet between a pair of the compression rolls to produce the electrode sheet.

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