Electrode sheet manufacturing apparatus

Abstract

To suppress changes in the amount of elongation of an unformed part of an electrode sheet.SOLUTION: An electrode sheet manufacturing apparatus is an apparatus for manufacturing an electrode sheet 10 including an unformed part 12a and an active material layer 14, the apparatus includes: a transport device 80 for transporting the electrode sheet 10; a support roll 61 for supporting the electrode sheet 10; a pressing roll 62 having a rubber layer in a surface thereof and disposed to face the support roll 61; and a driving device 73 for pressing the pressing roll 62 against the support roll 61. The pressing roll 62 presses the unformed part 12a between the pressing roll 62 and the support roll 61. The electrode sheet manufacturing apparatus stores a predetermined relationship between the transport speed of the electrode sheet 10 and the pressing force of the driving device 73, and controls the pressing force of the driving device 73 on the basis of the transport speed of the electrode sheet 10 and the stored relationship.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electrode sheet manufacturing apparatus. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2023-36089 discloses a method for manufacturing an electrode in a precursor sheet (electrode sheet) having a metal foil, a coated portion on the metal foil coated with an electrode material, and an uncoated portion on the metal foil not coated with the electrode material, in which the uncoated portion is pressed with a pair of elastic rolls (rubber rolls). The coated portion and the uncoated portion are pressed separately to adjust the difference in elongation. If the uncoated portion is pressed with a roll other than the elastic roll, tensile force generates voids inside the uncoated portion. These voids may cause the uncoated portion to break. By pressing the uncoated portion with a pair of elastic rolls, compressive force and deformation force can be applied to the same location of the uncoated portion. The compressive force is generated by contact between the pair of elastic rolls and deformation of the elastic body of the elastic roll. This allows the uncoated portion to be stretched while suppressing breakage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-36089 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present application have found that in the manufacturing method disclosed in the above publication, the amount of elongation of the unformed portion (uncoated portion) changes when the transport speed of the electrode sheet changes. [Means for solving the problem]

[0005] The electrode sheet manufacturing apparatus disclosed herein is an apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along the length of the current collector at a predetermined position in the width direction, and an active material layer formed on the current collector except for the unformed portion, and includes: a conveying device that conveys the electrode sheet along a predetermined conveying path; a support roll that is arranged on the conveying path and extends in the width direction of the electrode sheet to support a first surface of the electrode sheet conveyed along the conveying path; a pressing roll that has a rubber layer on its surface and is arranged on the second surface of the electrode sheet opposite the support roll and extends in the width direction of the electrode sheet; a driving device that drives at least one of the support roll and the pressing roll so that the pressing roll is pressed against the support roll; and a control device. The pressing roll is configured to sandwich the unformed portion of the electrode sheet except for the active material layer between the support roll and the pressing roll. The control device includes a memory unit that stores a predetermined relationship between the conveying speed of the electrode sheet by the conveying device and the pressing force of the drive device, and a control unit that controls the pressing force of the drive device based on the conveying speed of the electrode sheet and the relationship stored in the memory unit.

[0006] According to such an electrode sheet manufacturing device, by controlling the pressing force based on a predetermined relationship between the conveying speed of the electrode sheet and the pressing force applied to the unformed portion, it is possible to suppress changes in the amount of elongation of the unformed portion even when the conveying speed of the electrode sheet changes. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a flow diagram of the manufacturing process of the electrode sheet 10. [Figure 2] FIG. 2 is a schematic diagram of the electrode sheet 10. [Figure 3] FIG. 3 is a schematic side view of the electrode sheet manufacturing apparatus 1. As shown in FIG. [Figure 4] FIG. 4 is a front view of the roll press machine 60. As shown in FIG. [Figure 5]FIG. 5 is a cross-sectional view taken along the line AA shown in FIG. [Figure 6] FIG. 6 is a graph showing the relationship between the conveying speed of the electrode sheet 10 and the pressing force of the cylinder driving device 73. [Figure 7] FIG. 7 is a graph showing the relationship between the conveyance speed of the electrode sheet 10 and the amount of elongation of the uncoated portion 12a. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiment described here is, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, the same reference numerals are appropriately used for components and parts that perform the same function, and redundant explanations will be omitted where appropriate.

[0009] Fig. 1 is a flow diagram of the production of an electrode sheet 10 (see Fig. 2) by an electrode sheet manufacturing apparatus 1. As shown in Fig. 1, the production of an electrode sheet 10 by the electrode sheet manufacturing apparatus 1 includes a conveying step S1, a measuring step S2, a kneading step S3, a coating step S4, a drying step S5, and a roll press step S6. However, the production of an electrode sheet 10 by the electrode sheet manufacturing apparatus 1 may include other steps.

[0010] <Electrode sheet manufacturing equipment 1> An electrode sheet 10 that constitutes an electricity storage device is manufactured in an electrode sheet manufacturing apparatus 1. The electrode sheet 10 constitutes the positive electrode sheet or negative electrode sheet of an electrode body housed inside the electricity storage device. An electricity storage device refers to a device that can be repeatedly charged and discharged, and is a concept that encompasses so-called storage batteries (i.e., chemical batteries) such as lithium ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, as well as capacitors (i.e., physical batteries) such as electric double layer capacitors. Below, as an example, the configuration of an electrode sheet 10 used in a lithium ion secondary battery will be described, along with the electrode sheet manufacturing apparatus 1 that manufactures the electrode sheet 10.

[0011] <Electrode sheet 10> FIG. 2 is a schematic diagram of an electrode sheet 10. As shown in FIG. 2, the electrode sheet 10 includes a current collector 12 and an electrode active material layer 14. The current collector 12 is a member made of a long metal foil. The current collector 12 is a strip-shaped metal member. A metal material having a required conductivity can be used for the current collector 12. For example, aluminum or an aluminum alloy can be used for the positive electrode current collector foil. For example, copper or a copper alloy can be used for the negative electrode current collector foil. The electrode active material layer 14 is applied to a predetermined position on the current collector 12. The electrode active material layer 14 is formed on at least one surface of the strip-shaped current collector 12. In this embodiment, the electrode active material layer 14 is formed on both surfaces of the current collector 12. The electrode active material layer 14 is a layer containing an electrode active material. For example, a lithium transition metal composite oxide can be used as the positive electrode active material. Examples of the negative electrode active material that can be used include carbon materials, silicon-based materials, and mixed oxides thereof. The electrode active material layer may contain additives other than the electrode active material, such as a binder and a conductive material.

[0012] The electrode sheet 10 is formed by applying an electrode mixture slurry that will become the electrode active material layer 14 to a current collector 12 and drying the applied slurry. The current collector 12 has an uncoated portion 12a and a coated portion 12b. The uncoated portion 12a is a portion of the current collector 12 that is not coated with the electrode active material layer 14. The uncoated portion 12a is set along the length of the current collector 12 at a predetermined position in the width direction. In this embodiment, the uncoated portion 12a is set at both ends of the electrode sheet 10 in the width direction. The uncoated portion 12a is an example of an unformed portion set along the length of the current collector 12 at a predetermined position in the width direction, where the electrode active material layer 14 is not formed. The electrode active material layer 14 is formed on a portion of the current collector 12 excluding the uncoated portion 12a. Here, the electrode active material layer 14 is formed by coating the portion of the current collector 12 excluding the uncoated portion 12a. The coated portions 12b are disposed between the uncoated portions 12a on both ends of the electrode sheet 10. The electrode mixture slurry is applied to the coated portions 12b. As a result, an electrode active material layer 14 is formed on the coated portions 12b of the current collector 12. In other words, the electrode active material layer 14 is disposed between the uncoated portions 12a on both ends of the electrode sheet 10 in the width direction.

[0013] <Conveyor device 15> In the conveying step S1 shown in FIG. 1, the electrode sheet 10 is conveyed. FIG. 3 is a schematic side view of the electrode sheet manufacturing apparatus 1. The conveying step S1 can be achieved by a conveying device 15. The conveying device 15 conveys the long electrode sheet 10 along a predetermined conveying path 18. For example, a motor is used for the conveying device 15. As shown in FIG. 3, the conveying device 15 includes an unwinding roll 15a and a take-up roll 15b. The unwinding roll 15a is disposed upstream of the roll press machine 60 in the conveying direction. The take-up roll 15b is disposed downstream of the roll press machine 60 in the conveying direction. However, the conveying device 15 is not limited to the unwinding roll 15a and the take-up roll 15b. For example, the conveying device 15 may include rolls in addition to the unwinding roll 15a and the take-up roll 15b. In this embodiment, the roll press machine 60 described later is also provided with a roll driving device 80 and a support roll 61 (see Figure 4) rotated by the roll driving device 80, and the support roll 61 and the roll driving device 80 are also part of the conveying device 15.

[0014] <Measuring process S2, kneading process S3, coating process S4, drying process S5> In the measuring step S2 shown in FIG. 1, raw materials for the electrode active material layer 14 (see FIG. 2) are measured. The measuring can be achieved, for example, by a measuring device (not shown) having a balance, a load cell, or the like. The measured raw materials for the electrode active material layer 14 are mixed in the kneading step S3. The kneading step S3 can be achieved by a kneading device (not shown). The raw materials for the electrode active material layer 14, which have been made into a slurry by the kneading device, are applied to the current collector 12 (see FIG. 2) in the coating step S4. The coating step S4 can be achieved, for example, by a coating device (not shown) such as a slit coater, gravure coater, die coater, or comma coater. In the drying step S5, the applied raw materials for the electrode active material layer 14 in a slurry state are dried. The drying step S5 can be achieved, for example, by a drying device (not shown) that emits hot air or infrared rays.

[0015] <Roll Press Machine 60> In the roll press step S6, the electrode sheet 10 is pressed. The roll press step S6 can be achieved by a roll press machine 60 shown in FIG. 3. As shown in FIG. 3, the electrode sheet 10 is pressed by the roll press machine 60 midway along the conveying path 18. The electrode sheet 10 is supplied by an unwinding roll 15a. The electrode sheet 10 pressed by the roll press machine 60 is taken up by a take-up roll 15b. The electrode sheet manufacturing apparatus 1 includes a control device 100 that controls the unwinding roll 15a, the take-up roll 15b, and the roll press machine 60.

[0016] FIG. 4 is a front view of a roll press machine 60. The roll press machine 60 according to this embodiment is a device that presses the uncoated portion 12 a of the electrode sheet 10 with a rubber roll before or after pressing the electrode active material layer 14. When the uncoated portion 12 a is pressed by the rubber roll, the uncoated portion 12 a receives a reaction force from the elastic deformation and compressive deformation of the rubber roll, and the portion pressed by the roll is pressed and stretched. As a result, the uncoated portion 12 a can be stretched while preventing breakage of the uncoated portion 12 a. In view of this function, a device that presses the uncoated portion 12 a of the electrode sheet 10 with a rubber roll may be appropriately referred to as an EPS (Elasticity Powered Stretching) device. In addition to the roll press machine 60, the electrode sheet manufacturing apparatus 1 may also include a device that presses the electrode active material layer 14.

[0017] The roll press machine 60 includes a support roll 61, a pressing roll 62, a press pressure adjusting mechanism 70, and a roll driving device 80.

[0018] <Support Roll 61> The support roll 61 is disposed on the conveying path 18 (see FIG. 3). The support roll 61 extends in the width direction of the electrode sheet 10. The support roll 61 supports the lower surface 10D of the electrode sheet 10 conveyed along the conveying path 18 in the width direction of the electrode sheet 10. The lower surface 10D is an example of the first surface in the present invention. The support roll 61 is disposed below the pressing roll 62. The support roll 61 is a rubber roll that presses the uncoated portion 12a of the electrode sheet 10 together with the pressing roll 62. The support roll 61 comprises a main body portion 61a and two shaft portions 61b.

[0019] FIG. 5 is a cross-sectional view of the AA cross section shown in FIG. 4. However, FIG. 5 illustrates a state in which the uncoated portion 12a is pressed by the support roll 61 and the pressure roll 62. As shown in FIG. 5, the main body 61a includes a shaft portion 61aa and a rubber portion 61ab. The shaft portion 61aa is made of metal. The material forming the shaft portion 61aa is not particularly limited, but is, for example, a material with relatively high hardness such as SUS304 (stainless steel). The rubber portion 61ab is arranged to cover at least the outer peripheral surface of the shaft portion 61aa. The material forming the rubber portion 61ab is, for example, nitrile rubber (NBR). The support roll 61 presses the uncoated portion 12a of the electrode sheet 10 with the rubber portion 61ab.

[0020] The support roll 61 is rotated in a predetermined direction by a roll driving device 80 (see FIG. 4), which will be described later. In this embodiment, the support roll 61 rotates in the direction of arrow R1 shown in FIG. 5. At this time, the electrode sheet 10 is transported from left to right as viewed in the drawing. That is, the left side in FIG. 5 is the upstream side in the transport direction, and the right side in FIG. 5 is the downstream side in the transport direction.

[0021] As shown in Fig. 4, both shaft portions 61b are inserted into the main body portion 61a. Both shaft portions 61b are inserted into shaft portions 61aa (see Fig. 5) of the main body portion 61a. Both shaft portions 61b extend to the outside in the axial direction of the support roll 61. Although not shown, bearings, gap screws for adjusting the gap between the support roll 61 and the pressure roll 62, and the like are attached to both shaft portions 61b.

[0022] <Pressing Roll 62> As shown in FIG. 5, the pressing roll 62 is disposed on the side of the upper surface 10U of the electrode sheet 10 so as to face the support roll 61. The pressing roll 62 extends in the width direction of the electrode sheet 10. The pressing roll 62 is configured to sandwich the uncoated portions 12a of the electrode sheet 10, excluding the electrode active material layer 14 (see FIG. 2), between the pressing roll 62 and the support roll 61. The upper surface 10U is an example of the second surface of the present invention. The axial center of the pressing roll 62 and the axial center of the support roll 61 are aligned in the vertical direction. As shown in FIG. 4, the pressing roll 62 is a rubber roll that presses the uncoated portions 12a of the electrode sheet 10 together with the support roll 61. The pressing roll 62 is not disposed above the electrode active material layer 14 of the electrode sheet 10. In this embodiment, as described above, the uncoated portions 12a of the electrode sheet 10 are provided at both ends in the width direction of the electrode sheet 10. Therefore, as shown in FIG. 4, the pressing rolls 62 are respectively arranged above the uncoated portions 12a at both ends in the width direction of the electrode sheet 10. However, if there is only one uncoated portion 12a, there may be only one pressing roll 62. Of the two pressing rolls 62, the one arranged on the left will also be referred to as pressing roll 62L, and the one arranged on the right will also be referred to as pressing roll 62R. However, the name pressing roll 62 will be used appropriately in descriptions that apply to both pressing rolls 62L and 62R. The pressing roll 62 comprises a main body portion 62a and two shaft portions 62b.

[0023] The pressing roll 62 has a rubber layer on its surface. As shown in FIG. 5, the main body 62a includes a shaft 62aa and a rubber portion 62ab. The shaft 62aa is made of metal. The material for forming the shaft 62aa is not particularly limited, but is, for example, a material with relatively high hardness such as SUS304 (stainless steel). The rubber portion 62ab is arranged so as to cover at least the outer peripheral surface of the shaft 62aa. The material for forming the rubber portion 62ab is not particularly limited, but is, for example, nitrile rubber (NBR). The pressing roll 62 presses the uncoated portion 12a of the electrode sheet 10 with the rubber portion 62ab.

[0024] As shown in Fig. 4, both shaft portions 62b are inserted into the main body portion 62a. Both shaft portions 62b are inserted into shaft portions 62aa (see Fig. 5) of the main body portion 62a. Both shaft portions 62b extend to the outside in the axial direction of the two pressing rolls 62. Although not shown, both shaft portions 62b are fitted with bearings, gap screws for adjusting the gap between the support roll 61 and the pressing roll 62, and the like.

[0025] As shown in Fig. 5, when the support roll 61 and the pressure roll 62 sandwich the electrode sheet 10 and the support roll 61 rotates in the direction of arrow R1, the pressure roll 62 receives a force rotating in the direction of arrow R2 via the electrode sheet 10. Alternatively, when the electrode sheet 10 is not disposed and the support roll 61 and the pressure roll 62 are in contact, the pressure roll 62 receives a force rotating in the direction of arrow R2 due to the force of the rotation of the support roll 61. As a result, the pressure roll 62 rotates in the direction of arrow R2. In other words, the pressure roll 62 rotates in conjunction with the rotation of the support roll 61.

[0026] <Press pressure adjustment mechanism 70> As shown in FIG. 4, the press pressure adjusting mechanism 70 includes a press cylinder 71, a roll chock 72, a cylinder driving device 73, and a support portion 74.

[0027] The press cylinders 71 press the pressure roll 62 against the support roll 61. One press cylinder 71 is disposed on each end of the pressure roll 62, one on the outside. Here, in FIG. 4 , the press cylinder 71 disposed to the left of the electrode sheet 10 is referred to as press cylinder 71L, and the press cylinder 71 disposed to the right of the electrode sheet 10 is also referred to as press cylinder 71R. However, when describing matters common to the press cylinders 71L and 71R, they will also be referred to as press cylinder 71. In this embodiment, the press cylinder 71 is a pneumatic cylinder. The press cylinder 71 includes a rod 71a. The rod 71a is connected to a roll chock 72. The roll chock 72 is a member that rotatably supports both shaft portions 62b of the pressure roll 62. When the press cylinder 71 is driven and the rod 71a descends, the pressure roll 62 descends. When the press cylinder 71 is driven and the rod 71a rises, the pressure roll 62 rises.

[0028] The cylinder drive device 73 is a device that presses the pressure roll 62 against the support roll 61 while sandwiching the electrode sheet 10. The cylinder drive device 73 is an example of a drive device according to the present invention. The drive device drives at least one of the support roll 61 and the pressure roll 62 so that the pressure roll 62 is pressed against the support roll 61. In this embodiment, the cylinder drive device 73 drives the pressure roll 62. However, the drive device may also drive the support roll 61 or both the support roll 61 and the pressure roll 62. The cylinder drive device 73 is connected to the press cylinder 71. The cylinder drive device 73 drives the press cylinder 71, thereby raising and lowering the rod 71a of the press cylinder 71. In this embodiment, the cylinder drive device 73 is configured to independently drive the press cylinder 71L and the press cylinder 71R. That is, the cylinder drive device 73 independently drives the press rolls 62 disposed above the uncoated portions 12a at both ends of the electrode sheet 10 in the width direction. The cylinder driving device 73 is connected to a control device 100 (see FIG. 3).

[0029] The cylinder driving device 73 is configured to be able to change the pressing force of the press cylinder 71 based on an input from the control device 100. Here, the cylinder driving device 73 includes an electro-pneumatic regulator 73a. The electro-pneumatic regulator 73a controls the output air pressure in accordance with an input signal (for example, in accordance with an input voltage or current). Typically, the electro-pneumatic regulator 73a outputs air pressure proportional to the input voltage. However, the cylinder driving device 73 is not limited to one including the electro-pneumatic regulator 73a. Furthermore, the electro-pneumatic regulator 73a is not limited to one that controls voltage.

[0030] The support portion 74 is a member that supports the support roll 61. The support portion 74 supports both shaft portions 61b of the support roll 61.

[0031] <Roll driving device 80> The roll driving device 80 is connected to the support roll 61. The roll driving device 80 is a device that rotates the support roll 61. The roll driving device 80 and the support roll 61 are part of the roll press machine 60 and also part of the conveying device 15. In this embodiment, the roll driving device 80 rotates the support roll 61 in the direction of arrow R1 shown in FIG. 5. The configuration of the roll driving device 80 is not particularly limited, but here, the roll driving device 80 includes an electric motor 81. The electric motor 81 is connected to the control device 100 (see FIG. 3). The roll driving device 80 may also rotate the pressing roll 62.

[0032] The roll driving device 80 is equipped with a speed sensor 82 that acquires the rotation speed of the support roll 61. In this case, the speed sensor 82 is an encoder that emits a pulse each time the support roll 61 rotates by a predetermined angle. However, the speed sensor 82 may be an encoder built into the electric motor 81. Alternatively, the speed sensor 82 may be a sensor that directly measures the conveyance speed of the electrode sheet 10, for example, from the passage of a tab formed on the electrode sheet 10. The speed sensor 82 is not particularly limited as long as it can directly or indirectly measure the conveyance speed of the electrode sheet 10.

[0033] <Control device 100> 3, the control device 100 includes a speed acquisition unit 101, a pressure storage unit 102, and a pressure control unit 103. The configuration of the control device 100 is not particularly limited. The control device 100 includes, for example, a microcomputer. The microcomputer may include, for example, an interface (I / F) that receives data and the like from an external device, a central processing unit (CPU) that executes program instructions, a read only memory (ROM) that stores the program executed by the CPU, a random access memory (RAM) 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] The speed acquisition unit 101 acquires from the speed sensor 82 the speed at which the electrode sheet 10 is conveyed by the conveying device 15 (specifically, the roll driving device 80).

[0035] The pressure memory unit 102 stores a predetermined relationship between the conveying speed of the electrode sheet 10 by the conveying device 15 and the pressing force of the cylinder driving device 73. Fig. 6 is a graph showing the relationship between the conveying speed of the electrode sheet 10 and the pressing force of the cylinder driving device 73. As shown in Fig. 6, the relationship stored in the pressure memory unit 102 is such that the pressing force of the cylinder driving device 73 increases as the conveying speed of the electrode sheet 10 increases.

[0036] Graph G1 in FIG. 7 shows the relationship between the conveyance speed of the electrode sheet 10 and the elongation of the uncoated portion 12a of the electrode sheet 10 when the pressing force of the cylinder drive device 73 is constant. As shown in graph G1, according to the inventors' findings, when the conveyance speed of the electrode sheet 10 is slow, the elastic deformation time of the rubber portion 62ab of the pressing roll 62 is long, resulting in a large elongation of the uncoated portion 12a of the electrode sheet 10. When the conveyance speed of the electrode sheet 10 is fast, the elastic deformation time of the rubber portion 62ab of the pressing roll 62 is short, resulting in a small elongation of the uncoated portion 12a at the same pressing force. Therefore, to maintain a constant elongation of the uncoated portion 12a, it is necessary to increase the pressing force of the cylinder drive device 73 as the conveyance speed of the electrode sheet 10 increases. If the elongation of the uncoated portion 12a varies depending on the location, wrinkles may occur in the uncoated portion 12a or the electrode sheet 10 may break.

[0037] The pressing force of the cylinder driving device 73 relative to the conveying speed of the electrode sheet 10 is set so that the amount of elongation of the uncoated portions 12a is approximately the same regardless of the conveying speed of the electrode sheet 10. The graph in Figure 6 was obtained through experiments conducted to set the amount of elongation of the uncoated portions 12a of the electrode sheet 10 to a predetermined amount for multiple conveying speeds of the electrode sheet 10. Figure 7 shows, in graph G2, the relationship between the conveying speed of the electrode sheet 10 and the amount of elongation of the uncoated portions 12a when the pressing force control shown in Figure 6 is performed. As shown in graph G2, when the pressing force control shown in Figure 6 is performed, the amount of elongation of the uncoated portions 12a is approximately constant regardless of the conveying speed of the electrode sheet 10.

[0038] 6, while the conveying speed of the electrode sheet 10 is slow, the gradient of increase in the pressing force of the cylinder driving device 73 relative to the increase in the conveying speed of the electrode sheet 10 is large. As the conveying speed of the electrode sheet 10 increases, the gradient of increase in the pressing force of the cylinder driving device 73 relative to the increase in the conveying speed of the electrode sheet 10 decreases.

[0039] The pressure control unit 103 controls the pressing force of the cylinder driving device 73 based on the acquired conveying speed of the electrode sheet 10 and the relationship stored in the pressure memory unit 102. In this embodiment, the pressure control unit 103 applies a voltage corresponding to the pressing force of the cylinder driving device 73 to be applied to the electropneumatic regulator 73a.

[0040] <Press Control> The operation of pressing the uncoated portion 12a of the electrode sheet 10 by the roll press machine 60 will be described below.

[0041] First, the control device 100 (see FIG. 3) controls the cylinder drive device 73 and the roll drive device 80. The cylinder drive device 73 lowers the rod 71a of the press cylinder 71. The cylinder drive device 73 lowers the rod 71a to a predetermined position. This causes the pressing roll 62 to lower. At this time, the roll drive device 80 also rotates the support roll 61. In this embodiment, as shown in FIG. 5, the roll drive device 80 rotates the support roll 61 in the direction of arrow R1. When the pressing roll 62 lowers, the portion of the uncoated portion 12a sandwiched between the support roll 61 and the pressing roll 62 is compressed.

[0042] The control device 100 controls the conveying device 15 to convey the electrode sheet 10 at a predetermined speed. However, when the conveying device 15 accelerates at the start of conveying the electrode sheet 10, the conveying speed of the electrode sheet 10 is slower than the predetermined conveying speed. The conveying speed of the electrode sheet 10 gradually increases to approach the predetermined conveying speed. Therefore, when the conveying device 15 starts conveying the electrode sheet 10, the pressure control unit 103 weakens the pressing force of the cylinder driving device 73 compared to when the conveying speed of the electrode sheet 10 reaches a predetermined speed. Furthermore, when the conveying device 15 accelerates at the start of conveying the electrode sheet 10, the pressure control unit 103 gradually strengthens the pressing force of the cylinder driving device 73. This control prevents the amount of elongation of the uncoated portion 12a from becoming larger at the start of roll pressing than when the electrode sheet 10 is conveyed at a constant speed. Furthermore, it prevents the amount of elongation of the uncoated portion 12a from changing while the electrode sheet 10 is accelerating (the amount of elongation decreases as the conveying speed increases). As a result, as shown in graph G2 in FIG. 7, the amount of elongation of the uncoated portion 12a can be kept substantially constant regardless of the conveyance speed of the electrode sheet 10.

[0043] At the end of the roll press step S6, the electrode sheet 10 may be pressed while being decelerated. In this case, when the electrode sheet 10 is decelerated at the end of conveyance, the pressure control unit 103 weakens the pressing force of the cylinder driving device 73 compared to when the conveyance speed of the electrode sheet 10 is a predetermined speed. Furthermore, when the electrode sheet 10 is decelerated at the end of conveyance, the pressure control unit 103 gradually reduces the pressing force of the cylinder driving device 73. Furthermore, for example, when the conveyance speed is adjusted during conveyance of the electrode sheet 10 (for example, by feedback control in accordance with other parameters), the pressure control unit 103 controls the pressing force of the cylinder driving device 73 to a pressing force corresponding to the controlled conveyance speed.

[0044] <Effects of the embodiment> The following describes the effects that can be achieved by the electrode sheet manufacturing apparatus 1 according to this embodiment.

[0045] The electrode sheet manufacturing apparatus 1 according to this embodiment is a manufacturing apparatus for manufacturing an electrode sheet 10 having a current collector 12 made of a long metal foil, uncoated portions 12a set along the length of the current collector 12 at predetermined positions in the width direction, and an electrode active material layer 14 formed on the current collector 12 except for the uncoated portions 12a. The electrode sheet manufacturing apparatus 1 is equipped with: a conveying device 15 that conveys the electrode sheet 10 along a predetermined conveying path 18; a support roll 61 that is arranged on the conveying path 18 and extends in the width direction of the electrode sheet 10, and supports a lower surface 10D of the electrode sheet 10 conveyed along the conveying path 18; a pressing roll 62 that has a rubber portion 62ab on its surface, is arranged on the side of the upper surface 10U of the electrode sheet 10 so as to face the support roll 61, and extends in the width direction of the electrode sheet 10; a cylinder driving device 73 that drives at least one of the support roll 61 and the pressing roll 62 so that the pressing roll 62 is pressed against the support roll 61; and a control device 100. The pressure roll 62 is configured to sandwich the uncoated portion 12a of the electrode sheet 10, excluding the electrode active material layer 14, between itself and the support roll 61. The control device 100 includes a pressure memory unit 102 that stores a predetermined relationship between the conveying speed of the electrode sheet 10 by the conveying device 15 and the pressing force of the cylinder driving device 73, and a pressure control unit 103 that controls the pressing force of the cylinder driving device 73 based on the conveying speed of the electrode sheet 10 and the relationship stored in the pressure memory unit 102.

[0046] According to the electrode sheet manufacturing apparatus 1, by controlling the pressing force of the cylinder drive device 73 based on a predetermined relationship between the conveyance speed of the electrode sheet 10 and the pressing force pressing against the uncoated portion 12a, it is possible to suppress changes in the amount of elongation of the uncoated portion 12a even when the conveyance speed of the electrode sheet 10 changes. As a result, it is possible to suppress wrinkles in the uncoated portion 12a and breakage of the electrode sheet 10. Note that the reason the amount of elongation of the uncoated portion 12a changes when the conveyance speed of the electrode sheet 10 changes is because the elastic deformation time of the rubber portion 62ab of the pressing roll 62 changes with the change in conveyance speed; this phenomenon is unique to the technology of pressing and rolling a sheet with a rubber roll.

[0047] In this embodiment, the relationship stored in the pressure memory unit 102 is such that the pressing force of the cylinder drive device 73 increases as the conveying speed of the electrode sheet 10 increases. According to the knowledge of the present inventors, as the conveying speed of the electrode sheet 10 increases, the elastic deformation time of the rubber portion 62ab of the pressure roll 62 decreases, and therefore the amount of elongation of the uncoated portion 12a decreases at the same pressing force. Therefore, by controlling the pressing force of the cylinder drive device 73 based on the relationship that increases the pressing force of the cylinder drive device 73 as the conveying speed of the electrode sheet 10 increases, it is possible to suppress changes in the amount of elongation of the uncoated portion 12a.

[0048] In this embodiment, when the conveying device 15 accelerates the electrode sheet 10 at the start of conveyance, the pressure control unit 103 gradually increases the pressing force of the cylinder driving device 73. When the conveying device 15 accelerates the electrode sheet 10 at the start of conveyance, the conveying speed of the electrode sheet 10 gradually increases. Therefore, by controlling the cylinder driving device 73 to gradually increase the pressing force, it is possible to suppress changes in the amount of elongation of the uncoated portion 12a at the time of acceleration.

[0049] In this embodiment, when the conveying device 15 starts conveying the electrode sheet 10, the pressure control unit 103 weakens the pressing force of the cylinder driving device 73 compared to when the conveying speed of the electrode sheet 10 reaches a predetermined speed. When the electrode sheet 10 is accelerating at the start of conveyance, the conveying speed of the electrode sheet 10 is slower than when the electrode sheet 10 is conveyed at a constant speed after the acceleration ends. Therefore, by controlling the pressing force of the cylinder driving device 73 to be weaker during acceleration than when the electrode sheet 10 is conveyed at a constant speed, the difference in the amount of elongation of the uncoated portion 12a between when the electrode sheet 10 is accelerated and when the electrode sheet 10 is conveyed at a constant speed can be reduced.

[0050] Various embodiments of the invention disclosed herein have been described above. 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.

[0051] For example, in the above-described embodiment, the first surface of the electrode sheet 10 supported by the support rolls 61 is the lower surface 10D of the electrode sheet 10. However, the first surface of the electrode sheet 10 supported by the support rolls 61 does not have to face downward. The support rolls 61 may be configured to support the first surface of the electrode sheet 10 facing in another direction. Similarly, the second surface of the electrode sheet 10 is not limited to the upper surface 10U. The conveying direction of the electrode sheet 10 by the conveying device 15 is not limited to the horizontal direction, and may be bent along the way.

[0052] For example, in the above-described embodiment, the support roll 61 includes the rubber portion 61ab. However, it is sufficient that the rubber layer is provided at least on the pressing roll 62, and the support roll 61 does not necessarily have to include the rubber portion 61ab.

[0053] As described above, this specification includes the disclosures set forth in the following sections.

[0054] Section 1: 1. A manufacturing apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along a length direction of the current collector at a predetermined position in a width direction thereof, and an active material layer formed on a portion of the current collector excluding the unformed portion, a conveying device that conveys the electrode sheet along a predetermined conveying path; a support roll that is disposed in the transport path, extends in a width direction of the electrode sheet, and supports a first surface of the electrode sheet transported along the transport path; a pressing roll having a rubber layer on its surface, arranged on the second surface side of the electrode sheet so as to face the support roll, and extending in the width direction of the electrode sheet; a drive device that drives at least one of the support roll and the pressure roll so that the pressure roll is pressed against the support roll; a control device; the pressing roll is configured to sandwich the unformed portion of the electrode sheet, excluding the active material layer, between the pressing roll and the support roll, The control device a storage unit that stores a predetermined relationship between a conveying speed of the electrode sheet by the conveying device and a pressing force of the driving device; a control unit that controls the pressing force of the drive device based on the transport speed of the electrode sheet and the relationship stored in the storage unit. Electrode sheet manufacturing equipment.

[0055] Section 2: The relationship stored in the storage unit is a relationship in which the pressing force of the driving device is increased as the conveying speed of the electrode sheet increases. Item 1. The electrode sheet manufacturing apparatus according to item 1.

[0056] Section 3: When the conveyance device starts to accelerate the electrode sheet, the control unit gradually increases the pressing force of the drive device. Item 3. The electrode sheet manufacturing apparatus according to item 2.

[0057] Section 4: When the transport device starts transporting the electrode sheet, the control unit weakens the pressing force of the drive device compared to when the transport speed of the electrode sheet reaches a predetermined speed. Item 2 or 3. The electrode sheet manufacturing apparatus according to item 2 or 3. [Explanation of symbols]

[0058] 1. Electrode sheet manufacturing equipment 10 Electrode sheet 10D Bottom surface (1st surface) 10U top surface (second surface) 12 Current collector 12a Uncoated area (unformed area) 12b Coating Department 14 Electrode active material layer (active material layer) 15. Conveying equipment 15a Unwinding roll 15b Winding roll 18 Transport Route 60 Roll press machine 61 Support Roll 61a Main body 61aa Shaft 61ab Rubber part 61b Both shafts 62 Pressing roll 62a Main body 62aa shaft 62ab Rubber part (rubber layer) 62b Both shafts 70 Press pressure adjustment mechanism 71 Press Cylinder 71a Rod 72 Roll Chock 73 Cylinder drive unit (drive unit) 73a Electro-pneumatic regulator 74 Support part 80 Roll drive device (transport device) 81 Electric motor 82 Speed ​​sensor 100 control device 101 Speed ​​acquisition part 102 Pressure memory unit 103 Pressure control section S1 Transport process S2 Weighing process S3 kneading process S4 Coating process S5 Drying process S6 Roll press process

Claims

1. 1. A manufacturing apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along a length direction of the current collector at a predetermined position in a width direction thereof, and an active material layer formed on a portion of the current collector excluding the unformed portion, a conveying device that conveys the electrode sheet along a predetermined conveying path; a support roll that is disposed in the transport path, extends in a width direction of the electrode sheet, and supports a first surface of the electrode sheet transported along the transport path; a pressing roll having a rubber layer on its surface, disposed on the second surface side of the electrode sheet so as to face the support roll, and extending in the width direction of the electrode sheet; a drive device that drives at least one of the support roll and the pressure roll so that the pressure roll is pressed against the support roll; a control device; the pressing roll is configured to sandwich the unformed portion of the electrode sheet, excluding the active material layer, between the pressing roll and the support roll, The control device a storage unit that stores a predetermined relationship between a conveying speed of the electrode sheet by the conveying device and a pressing force of the driving device; a control unit that controls the pressing force of the drive device based on the transport speed of the electrode sheet and the relationship stored in the storage unit. Electrode sheet manufacturing equipment.

2. The relationship stored in the storage unit is a relationship in which the pressing force of the driving device is increased as the conveying speed of the electrode sheet increases. The electrode sheet manufacturing device according to claim 1 .

3. When the conveyance device starts to accelerate the electrode sheet, the control unit gradually increases the pressing force of the drive device. The electrode sheet manufacturing apparatus according to claim 2 .

4. When the transport device starts transporting the electrode sheet, the control unit weakens the pressing force of the drive device compared to when the transport speed of the electrode sheet reaches a predetermined speed. The electrode sheet manufacturing apparatus according to claim 2 .

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