Unwinding device and method for replacing electrode plate roll

Abstract

An unwinding device 100 according to the present disclosure comprises a roll replacement mechanism 30, a replacement nip 40, a cutter 50, and an encoder 60. The replacement nip 40 prohibits the movement of an electrode plate 10 in a forward direction and allows the movement of the electrode plate 10 in a reverse direction. The electrode plate 10 of an old roll 12a is cut by the cutter 50, an electrode plate roll 12 is changed from the old roll 12a to a new roll 12b, a terminal section of the electrode plate 10 of the old roll 12a and a starting end section of the electrode plate 10 of the new roll 12b are connected by tape 14, the electrode plate 10 is conveyed in the reverse direction while holding the electrode plate 10 by means of the replacement nip 40, the conveyance length of the electrode plate 10 is measured by an encoder 60, and the replacement nip 40 is released and the electrode plate 10 is conveyed in the forward direction in accordance with the measurement result of the encoder 60.

Description

Unwinding Device and Method for Exchanging Electrode Plate Rolls

[0001] The present disclosure relates to an unwinding device and a method for exchanging electrode plate rolls.

[0002] Batteries such as cylindrical batteries and prismatic batteries include wound electrode groups. The wound electrode group is produced by winding a strip-shaped negative electrode, a strip-shaped positive electrode, and a pair of separators around a winding core. The negative electrode and the positive electrode are supplied from negative electrode plate rolls and positive electrode plate rolls toward the winding core by an unwinding device.

[0003] As described in Patent Documents 1 and 2, when exchanging an electrode plate roll from an old roll to a new roll, the end portion of the electrode plate of the old roll is connected to the start portion of the electrode plate of the new roll. A tape is used for the connection between the end portion and the start portion.

[0004] Japanese Patent Application Laid-Open No. 2006-139974 Japanese Patent Application Laid-Open No. 2023-511050

[0005] When automatically exchanging an electrode plate roll from an old roll to a new roll in an unwinding device, the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll may fail. This is because when connecting the electrode plates with a tape, the tape may peel off from the current collector together with the composite layer. If the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll fails, the unwinding device needs to be stopped and manually restored. Moreover, not only does it take time for restoration, but a large amount of waste portions that cannot be used for products also occur in the strip-shaped electrode plates.

[0006] In view of the above circumstances, an object of the present disclosure is to provide a technique for reducing the operation loss of the unwinding device and the amount of electrode plate waste when the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll fails.

[0007] This disclosure provides an unwinding device for unwinding a strip-shaped electrode plate having an asphalt layer from an electrode plate roll, comprising: a roll exchange mechanism for exchanging the electrode plate roll from an old roll to a new roll; an exchange nip positioned on the transport path of the electrode plate, which prohibits the forward movement of the electrode plate and allows the reverse movement of the electrode plate; a cutter positioned on the transport path for cutting the electrode plate; and an encoder positioned on the transport path for measuring the transport length of the electrode plate, wherein the cutter cuts the electrode plate of the old roll, the electrode plate roll is exchanged from the old roll to the new roll, the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll are connected with tape, the electrode plate is transported in the reverse direction while holding the electrode plate with the exchange nip, the transport length of the electrode plate is measured with the encoder, and the exchange nip is released according to the measurement result from the encoder to transport the electrode plate in the forward direction.

[0008] According to this disclosure, it is possible to reduce the operating loss of the unwinding device and the amount of discarded electrode plates when the connection between the end of the electrode plate of the old roll and the start of the electrode plate of the new roll fails.

[0009] Figure 1 is a configuration diagram of an unwinding device according to one embodiment of the present disclosure. Figure 2 is a flowchart of the electrode roll replacement process performed in the unwinding device shown in Figure 1. Figure 3A is a diagram showing the electrode roll replacement process. Figure 3B is a diagram following Figure 3A. Figure 3C is a diagram following Figure 3B.

[0010] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below.

[0011] (Embodiment) Figure 1 is a configuration diagram of an unwinding device 100 according to one embodiment of the present disclosure. The unwinding device 100 comprises an unwinding shaft 20, a roll replacement mechanism 30, a replacement nip 40, a cutter 50, and an encoder 60. The unwinding device 100 is a device for unwinding a strip-shaped electrode plate 10 having an asphalt layer from an electrode plate roll 12. The electrode plate 10 is unwound from the unwinding device 100 and supplied toward a processing device (not shown) located downstream in the conveying direction. An example of a processing device is a winding device for winding the electrode plate 10 onto a core.

[0012] In this embodiment, the cutter 50, the replacement nip 40, and the encoder 60 are arranged in this order along the transport path of the electrode plate 10. The position of the replacement nip 40 may be reversed from the position of the encoder 60.

[0013] The electrode plate 10 is, for example, the positive or negative electrode of a lithium-ion secondary battery. The positive or negative electrode of a lithium-ion secondary battery has an asphalt layer (active material layer). When positive electrodes are connected to each other or negative electrodes are connected to each other with tape, the tape may peel off from the current collector along with the asphalt layer. Therefore, the technology of this disclosure is particularly useful when the electrode plate 10 is the positive or negative electrode of a lithium-ion secondary battery.

[0014] The unwinding shaft 20 is the shaft used to mount and rotate the plate roll 12. The unwinding shaft 20 is connected to the motor 22. The motor 22 can rotate the unwinding shaft 20 in the reverse direction. The unwinding shaft 20 and the motor 22 may also be configured to allow the unwinding shaft 20 to rotate in the forward direction. "Forward direction" is the direction in which the plate 10 is unwound from the plate roll 12. "Reverse direction" is the direction in which the plate 10 is wound onto the plate roll 12.

[0015] The motor 22 is, for example, a servo motor. With a servo motor, when the unwinding shaft 20 is rotated in the reverse direction, the length of the electrode plate 10 being transported in the reverse direction can be precisely controlled.

[0016] The roll replacement mechanism 30 is responsible for replacing the electrode plate roll 12 from the old roll 12a to the new roll 12b. The roll replacement mechanism 30 removes the old roll 12a from the unwinding shaft 20 and attaches the new roll 12b to the unwinding shaft 20.

[0017] The replacement nip 40 is positioned on the transport path of the electrode plate 10, preventing forward movement of the electrode plate 10 and allowing reverse movement of the electrode plate 10. The replacement nip 40 is used in the process of replacing the electrode plate roll 12. The electrode plate 10 is gripped by the replacement nip 40, and a load is applied to the electrode plate 10. While gripped by the replacement nip 40, the electrode plate 10 can only move upstream (i.e., in the reverse direction) of the transport direction. Therefore, even if the electrode plate 10 is cut between the electrode plate roll 12 and the replacement nip 40 while tension is applied, the electrode plate 10 cannot move downstream of the replacement nip 40.

[0018] When unwinding the electrode plate 10 from the electrode plate roll 12, the replacement nip 40 is in a released state, detached from the electrode plate 10.

[0019] The cutter 50 is positioned on the transport path of the electrode plates 10 and plays the role of cutting the electrode plates 10 during the electrode plate roll 12 replacement process. The cutter 50 is equipped with a blade and clamping claws. The clamping claws hold the electrode plates 10 of the old roll 12a, while the blade cuts the electrode plates 10 of the old roll 12a.

[0020] In this embodiment, the cutter 50 is configured to be able to advance in the direction toward the electrode roll 12 and retract in the direction toward the electrode roll 12, and also serves as a bonding machine that presses the end portion of the electrode plate 10 of the old roll 12a against the starting portion of the electrode plate 10 of the new roll 12b to connect them. However, the bonding machine may be provided separately from the cutter 50.

[0021] The encoder 60 is positioned on the transport path of the electrode plate 10 and measures the transport length of the electrode plate 10. The encoder 60 is, for example, a roller encoder equipped with rollers that rotate in contact with the electrode plate 10. When the electrode plate 10 is transported in the forward direction, the value measured by the encoder 60 is positive. When the electrode plate 10 is transported in the reverse direction, the value measured by the encoder 60 is negative.

[0022] The unwinding device 100 is further equipped with a transport roller 70. The transport roller 70 is driven by a motor (not shown) and is responsible for applying tension to the electrode plate 10 and transporting it in the forward direction.

[0023] The unwinding device 100 is further equipped with a controller 80. The controller 80 consists of components such as a PLC (Programmable Logic Controller) and a motor driver, and controls the operation of the motor 22, the roll changing mechanism 30, the replacement nip 40, the cutter 50, and the conveyor roller 70. The values ​​measured by the encoder 60 are input to the controller 80.

[0024] Figure 2 is a flowchart of the process of replacing the electrode roll 12 in the unwinding device 100 shown in Figure 1. Each process shown in the flowchart of Figure 2 is executed by the controller 80. Figures 3A to 3C show the process of replacing the electrode roll 12.

[0025] The process of replacing the electrode roll 12 is performed when a predetermined replacement initiation condition is met. The predetermined replacement initiation condition is, for example, when the remaining electrode plates 10 of the old roll 12a reach a threshold length. Alternatively, the predetermined replacement initiation condition may be when the length of the electrode plates 10 unwound from the old roll 12a reaches a specified value.

[0026] In step S1, the old roll 12a is stopped. More specifically, the motor connected to the transport roller 70 is stopped. This stops the rotation of the old roll 12a.

[0027] Next, in step S2, the electrode plates 10 of the old roll 12a are cut. Specifically, as shown in Figure 3A, the cutter 50 is operated to cut the electrode plates 10 of the old roll 12a. The transport path of the electrode plates 10 is adjusted by the movable roller 24 so that the electrode plates 10 of the old roll 12a face the cutter 50. The cutter 50 is brought close to the electrode plates 10 of the old roll 12a and the electrode plates 10 are held by the clamping claws of the cutter 50. The electrode plates 10 are cut while being held by the clamping claws.

[0028] In step S3, the replacement nip 40 is activated to hold the electrode plate 10 of the old roll 12a with the replacement nip 40. The electrode plate 10 of the old roll 12a is gripped by the replacement nip 40.

[0029] In step S4, the roll exchange mechanism 30 is activated to replace the electrode plate roll 12 from the old roll 12a to the new roll 12b. In this embodiment, the electrode plate roll 12 is replaced from the old roll 12a to the new roll 12b while the electrode plates 10 of the old roll 12a are held in place by the exchange nip 40. This method prevents the electrode plates 10 of the old roll 12a from being pulled downstream in the conveying direction and jumping during the replacement of the electrode plate roll 12.

[0030] Furthermore, as long as the electrode plate 10 of the old roll 12a is held by the replacement nip 40 when the electrode plate 10 is conveyed in the reverse direction, the timing of gripping the electrode plate 10 with the replacement nip 40 is not limited. In other words, the process in step S3 may be performed before cutting the electrode plate 10 of the old roll 12a, or after exchanging the old roll 12a with the new roll 12b.

[0031] In step S5, the electrode plates 10 are connected with tape. Specifically, the end of the electrode plate 10 of the old roll 12a and the beginning of the electrode plate 10 of the new roll 12b are connected with tape. As shown in Figure 3B, tape 14 is attached to the beginning of the electrode plate 10 of the new roll 12b. By pressing the end of the electrode plate 10 of the old roll 12a against the beginning of the electrode plate 10 of the new roll 12b, the electrode plate 10 of the old roll 12a and the electrode plate 10 of the new roll 12b are connected via tape 14. With this method, the end of the electrode plate 10 of the old roll 12a can be easily connected to the beginning of the electrode plate 10 of the new roll 12b.

[0032] In this embodiment, the cutter 50 also functions as an adhesive machine. The cutter 50 presses the end portion of the electrode plate 10 of the old roll 12a against the beginning portion of the electrode plate 10 of the new roll 12b. The tape 14 is, for example, double-sided tape.

[0033] In step S6, the electrode plate 10 is transported in the reverse direction for a predetermined length. Specifically, as shown in Figure 3C, the electrode plate 10 is transported in the reverse direction while being held by the exchange nip 40, and the transport length of the electrode plate 10 is measured by the encoder 60. The exchange nip 40 is released according to the measurement result by the encoder 60, and the electrode plate 10 is transported in the forward direction. The transport length of the electrode plate 10 in the reverse direction is, for example, 100 mm to 200 mm. The transport length of the electrode plate 10 in the reverse direction is determined according to the rotation angle of the unwinding shaft 20. The rotation angle of the unwinding shaft 20 is controlled by the motor 22.

[0034] Since the electrode plates 10 of the old roll 12a are connected to the electrode plates 10 of the new roll 12b, the measurement value of the encoder 60 matches a predetermined length controlled by the motor 22. However, if the tape 14 peels off and the connection between the electrode plates 10 of the old roll 12a and the electrode plates 10 of the new roll 12b fails, the measurement value of the encoder 60 will not reach the predetermined length controlled by the motor 22. Therefore, by referring to the measurement value of the encoder 60, it is possible to determine whether the connection between the electrode plates 10 of the old roll 12a and the electrode plates 10 of the new roll 12b was successful. Since the electrode plates 10 of the old roll 12a are held in place by the replacement nip 40, it is possible to prevent the electrode plates 10 of the old roll 12a from being pulled downstream in the conveying direction and jumping at the moment the tape 14 peels off. Therefore, even if the connection between the end of the electrode plate 10 of the old roll 12a and the beginning of the electrode plate 10 of the new roll 12b fails, the amount of electrode plate 10 to be discarded can be reduced. Furthermore, the time spent on recovery can also be reduced. In other words, according to the method of this embodiment, the operating loss of the unwinding device 100 can be reduced.

[0035] In step S7, it is determined whether the measured value of the encoder 60 is greater than or equal to a predetermined length. If the measured value of the encoder 60 is greater than or equal to a predetermined length (for example, 100 mm or more), that is, if the measurement result of the encoder 60 indicates that the transport length of the electrode plate 10 in the reverse direction has reached the predetermined length, in step S8, the replacement nip 40 is released and the electrode plate 10 is transported in the forward direction. This method allows for a smooth transition of the operation of the unwinding device 100 from the replacement process to the normal process. The time spent in the replacement process is also reduced.

[0036] If the measurement value from the encoder 60 is less than a predetermined length, that is, if the measurement result from the encoder 60 indicates that the transport length of the electrode plate 10 in the reverse direction has not reached a predetermined length, then in step S9, a notification is given that the connection between the end of the electrode plate 10 of the old roll 12a and the start of the electrode plate 10 of the new roll 12b has failed. With this method, the operator of the unwinding device 100 can quickly begin to restore the unwinding device 100.

[0037] The method for notifying that a connection has failed is not particularly limited. If a connection fails, the operation of the unwinding device 100 can be temporarily stopped, and the failure to connect can be notified to the outside of the unwinding device 100 by means of voice, images, or a combination thereof.

[0038] In the unwinding device 100 of this embodiment, the replacement nip 40 is positioned downstream in the transport path from the connection point between the end of the electrode plate 10 of the old roll 12a and the start of the electrode plate 10 of the new roll 12b. In this embodiment, the replacement nip 40 is positioned downstream of the cutter 50 in the transport direction and upstream of the encoder 60 in the transport direction. With this configuration, it is possible to prevent the electrode plate 10 of the old roll 12a from being pulled downstream in the transport direction and jumping at the moment the tape 14 is peeled off. The amount of electrode plate 10 wasted in the event of a connection failure can also be minimized.

[0039] In the unwinding device 100 of this embodiment, the encoder 60 is positioned downstream in the transport path from the connection point between the end of the electrode plate 10 of the old roll 12a and the start of the new roll 12b. In this embodiment, the encoder 60 is positioned downstream in the transport direction from the replacement nip 40. With this configuration, by referring to the measured value of the encoder 60, it is possible to reliably determine whether or not the connection between the electrode plate 10 of the old roll 12a and the electrode plate 10 of the new roll 12b has been successful.

[0040] According to the method of the present disclosure described above, it is possible to reduce the operation loss of the unwinding device 100 and the amount of waste of the electrode plate 10 when the connection between the end portion of the electrode plate 10 of the old roll 12a and the start portion of the electrode plate 10 of the new roll 12b fails.

[0041] (Other Embodiments) (Supplementary Note) By the description of the above embodiments, the following techniques are disclosed.

[0042] (Technique 1) An unwinding device that unwinds a strip-shaped electrode plate provided with a composite material layer from an electrode plate roll, the roll exchange mechanism that exchanges the electrode plate roll from an old roll to a new roll, an exchange nip that is arranged on the conveyance path of the electrode plate, prohibits the forward movement of the electrode plate, and allows the reverse movement of the electrode plate, a cutter that is arranged on the conveyance path and cuts the electrode plate, and an encoder that is arranged on the conveyance path and measures the conveyance length of the electrode plate. The unwinding device cuts the electrode plate of the old roll with the cutter, exchanges the electrode plate roll from the old roll to the new roll, connects the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll with a tape, conveys the electrode plate in the reverse direction while holding the electrode plate with the exchange nip, measures the conveyance length of the electrode plate with the encoder, and releases the exchange nip according to the measurement result by the encoder and conveys the electrode plate in the forward direction.

[0043] According to the present disclosure, it is possible to reduce the operation loss of the unwinding device and the amount of waste of the electrode plate when the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll fails.

[0044] (Technique 2) The unwinding device according to Technique 1, which exchanges the electrode plate roll from the old roll to the new roll while holding the electrode plate of the old roll with the exchange nip. According to such a method, it is possible to prevent the electrode plate of the old roll from being pulled downstream in the conveyance direction and jumping during the exchange of the electrode plate roll.

[0045] (Technology 3) When the measurement result indicates that the conveyance length of the electrode plate in the reverse direction has reached a predetermined length, the take-up device according to Technology 1 or 2, which releases the replacement nip and conveys the electrode plate in the forward direction. According to such a method, the operation of the take-up device can be smoothly shifted from the replacement process to the normal process.

[0046] (Technology 4) When the measurement result indicates that the conveyance length of the electrode plate in the reverse direction has not reached a predetermined length, the take-up device according to any one of Technologies 1 to 3, which notifies that the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll has failed. According to such a method, the administrator of the take-up device can promptly start to restore the take-up device.

[0047] (Technology 5) The take-up device according to any one of Technologies 1 to 4, in which the tape is attached to the start portion of the new roll, and the end portion of the electrode plate of the old roll is pressed against the start portion of the electrode plate of the new roll, thereby connecting the electrode plate of the old roll and the electrode plate of the new roll via the tape. According to such a method, the end portion of the electrode plate of the old roll can be easily connected to the start portion of the electrode plate of the new roll.

[0048] (Technology 6) The take-up device according to any one of Technologies 1 to 5, in which the replacement nip is arranged on the downstream side in the conveyance path than the connection position between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll. According to such a configuration, it is possible to prevent the electrode plate of the old roll from being pulled downstream in the conveyance direction and jumping at the moment when the tape is peeled off.

[0049] (Technology 7) The take-up device according to any one of Technologies 1 to 6, in which the encoder is arranged on the downstream side in the conveyance path than the connection position between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll. According to such a configuration, by referring to the measured value of the encoder, it is possible to surely determine whether the connection between the electrode plate of the old roll and the electrode plate of the new roll is successful.

[0050] (Technical 8) The unwinding device according to any one of Technical 1 to 7, wherein the electrode plate is the positive or negative electrode of a lithium-ion secondary battery.

[0051] (Technical 9) A method for replacing an electrode roll, on which a strip-shaped electrode plate having an asphalt layer is wound, from an old roll to a new roll, comprising: cutting the electrode plate of the old roll; replacing the electrode roll from the old roll to the new roll; connecting the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll with tape; holding the electrode plate with an exchange nip that prohibits the forward movement of the electrode plate and allows the reverse movement of the electrode plate, while transporting the electrode plate in the reverse direction and measuring the transport length of the electrode plate with an encoder; and releasing the exchange nip according to the measurement result by the encoder and transporting the electrode plate in the forward direction.

[0052] The technology disclosed herein is useful for manufacturing energy storage devices such as batteries and capacitors.

Claims

1. An unwinding device for unwinding a strip-shaped electrode plate having an asphalt layer from an electrode plate roll, comprising: a roll exchange mechanism for exchanging the electrode plate roll from an old roll to a new roll; an exchange nip positioned on the transport path of the electrode plate, which prohibits the forward movement of the electrode plate and allows the reverse movement of the electrode plate; a cutter positioned on the transport path for cutting the electrode plate; and an encoder positioned on the transport path for measuring the transport length of the electrode plate, wherein the cutter cuts the electrode plate of the old roll, the electrode plate roll is exchanged from the old roll to the new roll, the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll are connected with tape, the electrode plate is transported in the reverse direction while holding the electrode plate with the exchange nip, the transport length of the electrode plate is measured with the encoder, and the exchange nip is released according to the measurement result from the encoder to transport the electrode plate in the forward direction.

2. The unwinding device according to claim 1, wherein the electrode plate roll is replaced from the old roll to the new roll while the electrode plate of the old roll is held by the replacement nip.

3. The unwinding device according to claim 1, wherein if the measurement result indicates that the transport length of the electrode plate in the reverse direction has reached a predetermined length, the exchange nip is released and the electrode plate is transported in the forward direction.

4. The unwinding device according to claim 1, which, when the measurement result indicates that the transport length of the electrode plate in the reverse direction has not reached a predetermined length, notifies that the connection between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll has failed.

5. The unwinding device according to claim 1, wherein the tape is attached to the starting end of the new roll, and the electrode plates of the old roll and the electrode plates of the new roll are connected via the tape by pressing the end portion of the electrode plate of the old roll against the starting end of the electrode plate of the new roll.

6. The unwinding device according to claim 1, wherein the replacement nip is positioned downstream in the transport path from the connection point between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll.

7. The unwinding device according to claim 1, wherein the encoder is positioned downstream in the transport path from the connection point between the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll.

8. The unwinding device according to claim 1, wherein the electrode plate is the positive or negative electrode of a lithium-ion secondary battery.

9. A method for replacing an electrode roll, on which a strip-shaped electrode plate having an asphalt layer is wound, from an old roll to a new roll, comprising: cutting the electrode plate of the old roll; replacing the electrode roll from the old roll to the new roll; connecting the end portion of the electrode plate of the old roll and the start portion of the electrode plate of the new roll with tape; holding the electrode plate with an exchange nip that prohibits the forward movement of the electrode plate and allows the reverse movement of the electrode plate, while transporting the electrode plate in the reverse direction and measuring the transport length of the electrode plate with an encoder; and releasing the exchange nip according to the measurement result by the encoder and transporting the electrode plate in the forward direction.

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