Method for rolling electrode

Abstract

A method for rolling an electrode according to the present disclosure comprises: a step (A) of setting a rolling condition of the electrode; and a step (B) of rolling the electrode under a rolling condition, in which the rolling condition is a condition for achieving the electrode having the target thickness and includes a gap (gab) between the pair of rolling rollers, a back pressure on the rolling rollers, and a target load, and in which the target thickness of the electrode is achieved by adjusting the rolling condition in accordance with the load measured in step (B).

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0183575 filed on December 23, 2022, and Korean Patent Application No. 10-2023-0027509 filed on March 2, 2023, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.

[0003] The present disclosure relates to a method of rolling an electrode, and more particularly, to a method of rolling an electrode capable of continuously and consistently achieving a desired electrode thickness according to a load measured when rolling the electrode. Background Art

[0004] A secondary battery can be formed by inserting an electrode assembly consisting of a positive electrode plate, a negative electrode plate and a separator into a housing and then sealing the housing. A positive electrode plate or a negative electrode plate (hereinafter referred to as an "electrode plate") can be formed by applying an active material slurry to a predetermined thickness on a positive electrode collector or a negative electrode collector, and an electrode assembly can be formed by inserting a separator between the positive electrode collector and the negative electrode collector, and winding them multiple times in a jelly roll shape or laminating them into multiple layers.

[0005] The manufacturing process of the secondary battery mainly includes an electrode process, wherein the electrode process is divided into an active material mixing process, an active material coating process, a rolling process, a slitting process, a winding process, etc. More specifically, the electrode plate may be formed by a coated portion coated with an active material slurry and an uncoated portion not coated with the active material slurry. The rolling process of rolling the electrode plate may be included to increase the adhesion between the coated active material slurry and the electrode current collector and to increase the volume density of the active material. The rolled electrode plate may be cut into a predetermined size by a cutting machine having a certain width after drying and used.

[0006] Figures 1 to 3 1 is a conceptual diagram showing a rolling device for explaining an electrode rolling process.

[0007] Reference Figure 1 The rolling device for rolling the electrode includes a pair of rolling rollers 20 and 30. The thickness of the electrode 10 is reduced in the process of passing between the pair of rolling rollers.

[0008] When performing a roll-to-roll operation to manufacture a high-density electrode 10, the force (linear pressure) of the electrode 10 to open the two roll-to-roll rollers 20, 30 is large, which causes the rollers to bend, such as Figure 2As shown. Due to this bending deformation of the rolling rollers 20 and 30, the manufactured electrode 10 is formed thicker at the center of the width than at the two side edges, which results in quality defects. To solve the thickness deviation in this rolling process, back pressure is applied to both ends of the rolling rollers 20 and 30 to suppress bending, as Figure 3 shown. Summary of the Invention

[0009] Technical Problem

[0010] An object of the present disclosure is to provide a method for rolling an electrode that can continuously and consistently achieve a desired electrode thickness according to the load measured during the rolling of the electrode.

[0011] However, the technical problems to be solved by the embodiments of the present disclosure are not limited to the above problems, and various expansions can be made within the scope of the technical ideas included in the present disclosure.

[0012] Technical Solution

[0013] A method for rolling an electrode according to the present disclosure includes: step (A) of setting rolling conditions for the electrode; and step (B) of rolling the electrode under the rolling conditions, where the rolling conditions are conditions for achieving an electrode having a target thickness and include the gap (gab) between a pair of rolling rollers, the back pressure on the rolling rollers, and a target load, and where the target thickness of the electrode is achieved by adjusting the rolling conditions according to the load measured in step (B).

[0014] The method for rolling the electrode may include: step (C) of comparing the load measured during rolling with the target load; and step (D) of continuing to roll the subsequent electrode under the rolling conditions if the difference between the target load and the measured load does not deviate from a predetermined range.

[0015] Step (C) follows the following mathematical formula 1,

[0016] [Mathematical Equation 1]

[0017] |(P target )-(P measure )|≤A

[0018] where P target is the target load, P measure is the measured load, and A is a predetermined value selected as any one value from positive real numbers.

[0019] The method of roll-pressing an electrode further includes: step (E), if the difference between the target load and the measured load deviates from a predetermined range, adjusting the gap between the roll-pressing rollers by a predetermined amount, wherein after the step (E), the steps (B) and (C) are performed on subsequent electrodes with the adjusted gap between the roll-pressing rollers.

[0020] The step (E) and the subsequent steps (B) and (C) can be repeatedly performed until the difference between the target load and the measured load does not deviate from the predetermined range.

[0021] The predetermined range in the step (D) can be the error tolerance range of the target load.

[0022] The method of roll-pressing an electrode further includes: step (F), if the back pressure changes, adjusting the gap between the roll-pressing rollers, wherein the steps (B) and (C) are performed on subsequent electrodes with the adjusted gap between the roll-pressing rollers.

[0023] The change in the back pressure can be an automatic change or a manual change.

[0024] In the step (B), when the moving speed of the electrode is maintained for a predetermined period of time, the load on the electrode can be measured.

[0025] The roll-pressing conditions when achieving the target thickness of the electrode can be automatically stored in a data storage unit.

[0026] When performing primary roll-pressing on the electrode and subsequent secondary roll-pressing, the method can be applicable to at least one of the primary roll-pressing and the secondary roll-pressing.

[0027] Advantageous Effects

[0028] The method of roll-pressing an electrode according to the present disclosure can continuously and consistently achieve a desired electrode thickness according to the load measured during roll-pressing of the electrode.

[0029] In addition, when roll-pressing an electrode, according to the present disclosure, it is possible to roll-press the electrode in parallel with a thickness gauge to achieve a desired thickness, and in some cases, according to the present disclosure, it is possible to roll-press the electrode without a thickness gauge to achieve a desired thickness.

[0030] Therefore, the production efficiency of the electrode assembly can be maximized, the productivity can be improved, and the manufacturing cost can be reduced. In addition, the quality of the manufactured electrode assembly can be improved.

[0031] The effects that can be obtained from the present disclosure are not limited to the above-mentioned effects, and those skilled in the art will clearly understand other additional effects not mentioned herein from the description of the appended claims. Description of the Drawings

[0032] Figures 1 to 3 It is a conceptual diagram showing a rolling device for explaining an electrode rolling process.

[0033] Figure 4 It shows a flowchart of a method for rolling an electrode according to an embodiment of the present disclosure.

[0034] Figure 5 It shows when in accordance with Figure 4 a flowchart when the back pressure changes in the electrode rolling method.

[0035] Figure 6 It schematically shows an electrode rolling system (device) for implementing a method for rolling an electrode according to an embodiment of the present disclosure. Detailed Description of the Embodiments

[0036] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the drawings so that those skilled in the art can easily implement them. The present disclosure can be modified in various different ways and is not limited to the embodiments described herein.

[0037] For clarity, descriptions of parts irrelevant to the description will be omitted, and the same reference numerals denote the same or similar elements throughout the description.

[0038] In addition, in the drawings, for convenience of description, the sizes and thicknesses of the respective elements are arbitrarily shown, and the present disclosure is not necessarily limited to the sizes and thicknesses shown in the drawings. In the drawings, the thicknesses of multiple layers and regions are enlarged to clearly represent them. In the drawings, for convenience of description, the thicknesses of some layers and regions are enlarged.

[0039] Now, with reference to Figure 4 and Figure 5 a method for rolling an electrode according to an embodiment of the present disclosure will be described.

[0040] Figure 4 It shows a flowchart of a method for rolling an electrode according to an embodiment of the present disclosure.

[0041] In Figure 4 the method for rolling an electrode shown, first, step S110 is performed to set the rolling conditions of the electrode. The rolling conditions are conditions for realizing an electrode 10 having a target thickness, and the rolling conditions include the gap (gab) between a pair of rolling rollers 20, 30, the back pressure on the rolling rollers 20, 30, and the target load. The rolling conditions can be directly input into a rolling device 100 that performs the method for rolling an electrode (see Figure 6) The input / output unit 150, or data of the rolling conditions pre-stored in the data storage unit 140 can be applied.

[0042] Next, step S120 is executed to roll the electrode 10 with the rolling rollers 20 and 30.

[0043] At the start of the process, step S120 is executed under the rolling conditions in step S110. In other words, the electrode 10 is rolled in the gap between the rolling rollers 20 and 30 set in step S110 and under the back pressure on the rolling rollers 20 and 30 set in step S110. Additionally, as will be described later, when the rolling conditions are adjusted during the rolling process, step S120 is executed under the adjusted rolling conditions. This part will be described in detail in step S150 below.

[0044] In step S120, the actual load on the rolling rollers 20 and 30 when rolling the electrode 10 is measured. This is because, even though the target load is set in step S110, due to various environments of the actual rolling process, it may not be possible to perform rolling precisely at the target load, and errors may occur. Additionally, the rolling conditions can be adjusted as described later based on the load measured in step S120, so that the target thickness of the electrode 10 can be achieved.

[0045] The rolling rollers 20 and 30 can use at least a pair of rolling rollers facing each other used in a normal electrode rolling process. The actual load on the rolling rollers 20 and 30 is measured by a load sensor (loadcell, not shown). For example, when the moving speed of the electrode 10 is maintained for a predetermined period, it is determined that step S120 is in a normal operating state, and the actual load on the rolling rollers 20 and 30 can be measured. Or, for example, step S120 is executed, and at the same time, the actual load on the rolling rollers 20 and 30 can also be continuously measured in real time.

[0046] Next, step S130 is executed to compare the load measured during rolling with the target load. The load measured during rolling refers to the actual load measured in step S120. The target load is the target load set in step S110, which refers to the load reflected by the target thickness of the electrode 10. In step S130, for example, the difference between the measured load and the target load is calculated, and it is determined whether the difference falls within a predetermined range (for example, the error tolerance range). For example, the following mathematical formula 1 can be applied.

[0047] [Mathematical formula 1]

[0048] |(P target ) – (P measure )| ≤ A

[0049] Where, P targetis the target load, P measure is the measured load, and A is a predetermined value (any value selected from positive real numbers). A can be selected to match various process environments and / or electrode types, or can be predetermined. For example, A can be a preset error tolerance value that matches various process environments and / or electrode types.

[0050] Next, as a result of the comparison in step S130, if the difference between the target load and the measured load does not deviate from the predetermined range, step S140 is executed, and the subsequent electrodes are continuously roll-pressed under the preset roll-pressing conditions.

[0051] If the actual load measured during the roll-pressing of electrode 10 in step S120 satisfies the predetermined range (e.g., error tolerance range) based on the target load, it is determined that the roll-pressing of electrode 10 in step S120 is performed at the target load. In other words, it is determined that electrode 10 is being roll-pressed to the target thickness. Thus, for the subsequent electrodes 10 entering the roll-pressing rollers 20, 30, the roll-pressing can be continuously performed under the preset roll-pressing conditions (e.g., the gap between the roll-pressing rollers 20, 30, and the back pressure on the roll-pressing rollers 20, 30).

[0052] However, as a result of the comparison in step S130, if the difference between the target load and the measured load deviates from the predetermined range, step S150 is executed to adjust the gap between the roll-pressing rollers by a predetermined amount.

[0053] If the actual load measured during the roll-pressing of electrode 10 in step S120 does not satisfy the predetermined range (e.g., error tolerance range) based on the target load, it is determined that the roll-pressing of electrode 10 in step S120 is not performed at the target load. In other words, it is determined that electrode 10 is not being roll-pressed to the target thickness. Thus, the gap between the roll-pressing rollers 20, 30 is adjusted to achieve the target thickness of the subsequent electrodes 10 entering the roll-pressing rollers 20, 30.

[0054] In step S150, the gap between the roll-pressing rollers 20, 30 is adjusted by a predetermined amount within a predetermined time period. After that, steps S120 and S130 are performed on the subsequent electrodes 10 entering the roll-pressing rollers 20, 30. That is, steps S120 and S130 are performed under the adjusted roll-pressing conditions (the adjusted gap between the roll-pressing rollers). At this time, as described above in step S120, under the adjusted roll-pressing conditions (the adjusted gap between the roll-pressing rollers), the actual load of the roll-pressing rollers 20, 30 for roll-pressing electrode 10 is measured. In addition, in step S130, the load measured during the roll-pressing is compared with the target load under the adjusted roll-pressing conditions.

[0055] Subsequently, as a result of the comparison in step S130, as described above in step S140, if the difference between the target load and the measured load (i.e., the load during rolling under the adjusted rolling conditions) does not deviate from the predetermined range, rolling of the subsequent electrode is continued under the adjusted rolling conditions. In other words, if a load within the error tolerance range of the target load is measured under the adjusted rolling conditions (the gap between the adjusted rolling rolls), rolling of the electrode 10 can be continued as in step S140.

[0056] However, as a result of the comparison in step S130, as described above in step S150, if the difference between the target load and the measured load deviates from the predetermined range, the rolling conditions (the gap between the rolling rolls) are readjusted by a predetermined amount. In other words, if a load within the error tolerance range of the target load is not measured under the adjusted rolling conditions (the adjusted gap between the rolling rolls), the rolling conditions (the gap between the rolling rolls) are readjusted again through step S150. By repeating steps S150, S120, and S130 in this way, when rolling the electrode 10 under the adjusted rolling conditions (the gap between the adjusted rolling rolls), a load within the error tolerance range of the target load is measured, enabling the rolling of the electrode 10 to be continued as in step S140.

[0057] In addition, if the rolling of the electrode 10 is continued in step S140, due to various process environment reasons, the desired thickness (target thickness) of the electrode 10 may not be achieved, or the thickness of the electrode 10 may be uneven. To ensure that the electrode 10 can be normally and uniformly rolled to the target thickness, the back pressure of the rolling rolls 20 and 30 needs to be changed as appropriate.

[0058] If this back pressure is changed, step S160 is further executed to adjust the gap between the rolling rolls. In this regard, Figure 5 shows a flowchart when the back pressure changes in the Figure 4 electrode rolling method.

[0059] First, the change in the back pressure can be an automatic change or a manual change. An automatic change means that when the process environment or the like changes, the back pressure applied to the rolling rolls 20 and 30 is changed according to an algorithm (program) preset for the process. A manual change means that when an operator in the process sets the back pressure value and inputs it into the input / output unit 150, the back pressure applied to the rolling rolls 20 and 30 is changed by the back pressure value input into the input / output unit 150.

[0060] In addition, when the back pressure applied to the rolling rollers 20 and 30 changes, the load applied to the electrode 10 by the rolling rollers 20 and 30 also changes. This is because the load is calculated by multiplying the pressure by the area, and the back pressure is the pressure applied in the direction opposite to the linear pressure that is the pressure applied to the electrode by the rolling rollers 20 and 30. Additionally, since the load applied to the electrode 10 is changed by the rolling rollers 20 and 30, it is necessary to adjust the load applied to the electrode 10 so that it becomes the target load again.

[0061] Accordingly, when there is a change in the back pressure, step S160 is further executed to adjust the gap between the rolling rollers. Based on the adjusted gap between the rolling rollers, step S120 is executed, and then step S130 as described above is executed.

[0062] Similarly, as a result of the comparison in step S130, as described above in step S140, if the difference between the target load and the measured load (i.e., the load during rolling under the adjusted rolling conditions) does not deviate from a predetermined range, rolling of the subsequent electrodes is continued under the adjusted rolling conditions.

[0063] However, as a result of the comparison in step S130, as described above in step S150, if the difference between the target load and the measured load deviates from the predetermined range, the rolling conditions (the gap between the rolling rollers) are readjusted by a predetermined amount. When rolling the electrode 10 under the adjusted rolling conditions (the adjusted gap between the rolling rollers), steps S150, S120, and S130 are repeated until a load within the error tolerance range of the target load is measured.

[0064] The above-described embodiments of the present disclosure can be particularly effectively applied to a process in which a thickness gauge for the electrode 10 is not provided when rolling the electrode 10. Alternatively, the rolled electrode 10 can be manufactured to a desired thickness (target thickness) without individually measuring the thickness of the electrode 10. This is because the rolling rollers 20 and 30 perform rolling with a target load, thereby achieving the target thickness of the electrode 10. Of course, the present disclosure is not limited thereto, and if a thickness gauge is provided, the present disclosure can be applied in parallel with the thickness gauge, and the thickness of the electrode 10 can be more effectively achieved as the desired thickness (target thickness).

[0065] The above-described embodiments of the present disclosure can be applied to, for example, the manufacturing process of the negative electrode. In some cases, in the case of the negative electrode, a phenomenon (springback phenomenon) may occur in which the rolled electrode expands again after the first rolling. Therefore, when manufacturing the negative electrode, secondary rolling is performed after the first rolling. The above-described embodiments of the present disclosure can be applied to, for example, the first rolling. This is because it is easy to achieve the desired thickness of the first rolling of the electrode with the target loads of the rolling rolls 20 and 30 without measuring the thickness of the electrode 10. In other words, it is sufficient to measure the thickness of the final electrode manufactured by the secondary rolling after the first rolling. However, the present disclosure is not limited to the above, and can also be applied during the secondary rolling of the electrode (negative electrode). In addition, various modifications and changes can be made, such as the embodiments of the present disclosure being applicable to the manufacturing process of the positive electrode that can be sufficiently manufactured by the first rolling.

[0066] Figure 6 An electrode rolling system (apparatus) for implementing a method of rolling an electrode according to an embodiment of the present disclosure is schematically shown.

[0067] The method of rolling an electrode according to an embodiment of the present disclosure can be implemented in an electrode rolling system 100 including a rolling unit 110, a transceiver 120, a controller 130, and an input / output unit 150 as shown in Figure 6 .

[0068] As the rolling unit 110, a rolling device commonly used in the electrode manufacturing process can be used, and thus its detailed description is omitted. The rolling unit 110 can include rolling rolls 20 and 30 as shown in Figure 1 ; a back pressure cylinder (not shown); various sensors (not shown), etc. The sensors can include a sensor for measuring the gap between the rolling rolls 20 and 30, a load sensor for measuring the load of the rolling rolls 20 and 30, etc. In addition, a temperature sensor for measuring the temperature of the rolling rolls 20 and 30, a speed sensor for measuring the moving speed of the electrode or the driving speed of the rolling rolls, etc. can be included.

[0069] The transceiver 120 receives data transmitted from sensors provided in the rolling unit 110 or receives data transmitted from the operator's input / output unit 150 and transmits the data to the controller 130. The data transmitted to the controller 130 can include the gap between the rolling rolls and / or the back pressure change (or back pressure) value as described above, and optionally may further include the rolling temperature, the rolling speed, etc.

[0070] The controller 130 receives data such as the actual load of these measurements and compares it with the target load. As a subsequent step, it is determined whether to execute step S140 or step S150. The controller 130 can be integrated into the system 100 for electrode rolling or connected to an external data storage unit 140.

[0071] In the process of performing the method of rolling an electrode according to an embodiment of the present disclosure, when the target load is achieved, data related to the rolling conditions at that time (the gap between the rolling rollers, the back pressure, the rolling temperature, the rolling speed, the electrode moving speed, etc.) can be stored in the data storage unit 140.

[0072] For components related to other devices required for implementing the method of rolling an electrode according to an embodiment of the present disclosure, refer to the equipment used in typical electrode rolling processes.

[0073] Based on the method of rolling an electrode according to an embodiment of the present disclosure, it is possible to achieve the target load of the electrode 10 at the target load according to the process conditions without a thickness gauge for the electrode 10 and without operator intervention. In other words, the desired thickness after rolling can be consistently achieved and maintained without the operator having to complete the process of individually confirming the thickness. Additionally, even when used in parallel with a thickness gauge, the desired thickness after rolling can be more effectively and consistently achieved and maintained.

[0074] Therefore, it has the effects of maximizing the efficiency of the electrode manufacturing process, improving productivity, and reducing manufacturing costs.

[0075] In addition, based on the method of rolling an electrode according to an embodiment of the present disclosure, the thickness of the rolled electrode can be made the same, thereby balancing and improving the quality of the secondary battery including the electrode manufactured thereby, and significantly reducing the defect rate.

[0076] Although the present invention has been described in detail above with reference to its preferred embodiments, those skilled in the art will understand that the scope of the present disclosure is not limited thereto, and various modifications and improvements can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined in the appended claims and their equivalents.

[0077] [Description of Reference Numerals]

[0078] 10: Electrode

[0079] 20, 30: Rolling rollers

[0080] 100: Electrode rolling system

[0081] 110: Rolling unit

[0082] 120: Transceiver

[0083] 130: Controller

[0084] 140: Data storage unit

[0085] 150: Input / output unit.

Claims

1. A method for rolling an electrode, comprising: Step (A), setting the rolling conditions of the electrode; And Step (B), rolling the electrode under the rolling conditions, wherein the rolling conditions are conditions for achieving an electrode with a target thickness, and include the gap (gab) between a pair of rolling rollers, the back pressure on the rolling rollers, and the target load, and wherein the target thickness of the electrode is achieved by adjusting the rolling conditions according to the load measured in step (B).

2. The method for rolling an electrode according to claim 1, comprising: Step (C), comparing the load measured during rolling with the target load; And Step (D), if the difference between the target load and the measured load does not deviate from a predetermined range, continuing to roll the subsequent electrodes under the rolling conditions.

3. The method for rolling an electrode according to claim 2, wherein: Step (C) follows the following mathematical formula 1, [Mathematical formula 1] |(P target )-(P measure )|≤A where P target is the target load, P measure is the measured load, and A is a predetermined value that is any value selected from the positive real numbers.

4. The method for rolling an electrode according to claim 2, further comprising: Step (E), if the difference between the target load and the measured load deviates from the predetermined range, adjusting the gap between the rolling rollers by a predetermined amount, wherein after step (E), steps (B) and (C) are performed on subsequent electrodes with the adjusted gap between the rolling rollers.

5. The method for rolling an electrode according to claim 4, wherein: Steps (E) and the subsequent steps (B) and (C) are repeatedly performed until the difference between the target load and the measured load does not deviate from the predetermined range.

6. The method for rolling an electrode according to any one of claims 3 to 5, wherein: The predetermined range in step (D) is the error tolerance range of the target load.

7. The method for rolling an electrode according to claim 2, further comprising: Step (F), if the back pressure changes, adjusting the gap between the rolling rollers, wherein steps (B) and (C) are performed on subsequent electrodes with the adjusted gap between the rolling rollers.

8. The method for rolling an electrode according to claim 7, wherein: The change in the back pressure is an automatic change or a manual change.

9. The method for rolling an electrode according to claim 1, wherein: In step (B), when the moving speed of the electrode remains for a predetermined period of time, the load on the electrode is measured.

10. The method for rolling an electrode according to claim 1, wherein: The rolling conditions when achieving the target thickness of the electrode are automatically stored in a data storage unit.

11. The method for rolling an electrode according to claim 1, wherein: When performing primary rolling on the electrode and subsequent secondary rolling, the method is applicable to at least one of the primary rolling and the secondary rolling.

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