Distortion correction device for electrodes and distortion correction method for electrodes

Abstract

The present technology provides a skew correction device and a method of correcting electrode skew when electrodes are conveyed, which corrects the input inclination of electrodes using data of the determined edge position sensor (EPS) edge position values of the electrodes that vary over time when the edge position of the electrodes is feedback-controlled by an edge position control (EPC) unit before the electrodes are wound on a winding core, to improve instability when the electrodes are input.

Description

Technical Field

[0001] This invention relates to a skew correction device and a method for correcting skew during electrode transfer. More specifically, this invention relates to a skew correction device and a method for correcting skew during the transfer of electrodes to a core for winding onto the core to form a jelly roll electrode assembly.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0026290, filed on February 26, 2021, the entire contents of which are incorporated herein by reference. Background Technology

[0003] With technological advancements and the increasing demand for mobile devices, automobiles, and energy storage devices, the demand for batteries as an energy source has increased dramatically. Numerous studies have been conducted on lithium secondary batteries, which possess high energy density and high discharge voltage, and lithium secondary batteries have been commercialized and widely used.

[0004] Specifically, lithium secondary batteries have an operating voltage of 3.6V or higher, which is three times the operating voltage of nickel-cadmium or nickel-metal hydride batteries, which are widely used as power sources for portable electronic devices. As a result, lithium secondary batteries have rapidly expanded in terms of high energy density per unit weight.

[0005] An electrode assembly has a structure with a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes. Generally, secondary batteries can be classified according to the structure of the electrode assembly as follows: a jelly roll (wound type) electrode assembly with a separator inserted between long sheet-shaped positive and negative electrodes and then wound; a stacked (laminated type) electrode assembly in which multiple positive and negative electrodes cut to a predetermined size are sequentially stacked with separators inserted between them; a stacked folded electrode assembly, in which a unit cell, such as a bi-cell or full cell, is stacked with a separator inserted between it and then wound; and so on.

[0006] Among these electrode assemblies, the jelly roll electrode assembly has the advantages of being easy to manufacture and having a high energy density per unit weight. Specifically, the high-energy-density jelly roll electrode assembly can be housed in a cylindrical metal can to form a cylindrical secondary battery, which is widely used in fields requiring high-capacity secondary batteries, such as electric vehicles.

[0007] To form the jelly roll electrode assembly, electrodes are input through an input fixture, conveyed toward the core, and wound onto the core to form the jelly roll electrode assembly. Specifically, a diaphragm is also conveyed together with electrodes such as positive and negative electrodes and wound together onto the core to form the jelly roll electrode assembly.

[0008] Ideally, the electrode travels correctly from input to core, thus aligning with the set edge reference value when transferred to the core. However, in reality, skew inevitably occurs, where the electrode travels outside the set edge reference value during transfer.

[0009] Figure 1 This is a schematic diagram illustrating a conventional electrode skew correction device and correction method utilizing an End-Edge Position Control (EPC) unit.

[0010] like Figure 1 As shown, the electrode 1, input via the input clamp 10, travels toward the core 60 and is wound onto the core 60 together with the diaphragm via the final roller 50 to form a jelly roll electrode assembly. During winding with the core 60, the input-side end of the electrode is cut by the cutter 20, and the cut end is also wound onto the core 60 to form the jelly roll electrode assembly.

[0011] Conventional electrode skew correction devices correct electrode skew by setting a final EPC (Edge Position Control) unit 30 in front of the final roller.

[0012] In other words, the final EPC unit 30 uses an edge position sensor (EPS) 32 installed at a predetermined position (Q: for example, approximately 100 mm before the core 60) to measure the edge position of electrode 1. This edge position of electrode 1 is represented as the determined EPS edge position value. The EPS sensor 32 can be a sensor that measures the electrode edge position in a non-contact manner, such as a light emitting and receiving sensor. When the determined EPS edge position value differs from the set determined EPS edge reference value A, the controller 40 performs feedback control by moving the electrode in the width direction using the EPC roller 31 installed in the final EPC unit, thereby aligning the electrode edge position with the determined EPS edge reference value A. In this case, the determined EPS edge reference value A is not 0, but a set value determined in the determined EPS based on the electrode's roll-to-roll process conditions, etc. Therefore, the reference value can also change when the process conditions change. For example, the determined EPS edge reference value can be 0.8 mm.

[0013] EPC roller 31 can be, for example, a clamping roller located in the vertical direction of the electrode. Electrode position correction can be performed by EPC roller 31 at a predetermined position (P: for example, approximately 125 mm before the core) before determining EPS 32.

[0014] However, even after correcting the skewed travel of the electrodes using the final EPC unit 30, it was confirmed that a significant number of skew defects still occurred during the electrode travel. Specifically, the skew defect rate was high for the negative electrode. This is because, even after the skew was corrected by the final EPC unit 30, skew defects could still unexpectedly occur at the input electrode.

[0015] Figure 2 This is a schematic diagram illustrating the impact of input instability when skew is corrected by the final EPC unit.

[0016] That is to say, such as Figure 2 As shown, because the input clamp 10 is tilted when the electrode is input, the input electrode is also tilted. As a result, the position of the electrode measured by the EPS 32 is also skewed and measured. The input clamp 10 is a clamp for inputting the electrode into the core, and may include, for example, an input clamp roller configured as a clamping roller. Figure 2 In the reference numeral 1a, an electrode is biased and tilted due to the tilt of the input fixture 10 (specifically, the tilt of the input fixture roller).

[0017] When this unexpected misalignment defect occurs, the electrode assembly cannot be wound according to the design values, thus adversely affecting the performance of the finished battery. This unexpected misalignment defect is identified, for example, as instability of the electrode input via input fixture 10. That is, if electrode 1 is initially input in the misalignment direction, even if it is subsequently input via fixture 10... Figure 1 The final EPC unit 30 shown corrects the skewness, but due to the limited skewness correction effect as described above, the skewness defect rate increases.

[0018] Therefore, it is desirable to develop a technique that can prevent unexpected skew defects by improving the instability during electrode input.

[0019] [Existing Technical Documents]

[0020] [Patent Literature]

[0021] Korean Patent Publication No. 10-1113424 Summary of the Invention

[0022] Technical issues

[0023] The present invention aims to provide a skew correction device during electrode transfer, wherein instability during electrode input is improved by using edge position sensor (EPS) edge position value data of the electrode changing over time during feedback control via an edge position control (EPC) unit before the electrode is wound onto the core.

[0024] Furthermore, the present invention aims to provide a method for correcting electrode skew, wherein the input tilt of the input fixture is controlled by feedback control that compares determined EPS edge position value data with determined EPS edge reference value.

[0025] Technical solution

[0026] The electrode skew correction device according to the present invention is a skew correction device for conveying electrodes to be wound onto a core to form a jelly roll electrode assembly. The electrode skew correction device includes: an input tilt adjustment mechanism for an input clamp configured to input the electrode into the core; an edge position control unit (EPC) provided with an edge position sensor (EPS) and an EPC roller, the EPS being disposed before the core to measure the edge position of the electrode as an EPS edge position value, the EPC roller being configured to adjust the edge position of the electrode to align with the EPS edge reference value; and a controller configured to... To control the EPC unit and the input tilt adjustment mechanism, the controller provides feedback control over the edge position of the electrode, ensuring that the determined EPS edge position value matches the determined EPS edge reference value; it obtains determined EPS edge position value data when, through the feedback control, the determined EPS edge position value converges to the determined EPS edge reference value over time; it selects data values ​​from the determined EPS edge position value data that vary due to the input tilt of the input fixture, and provides feedback control over the input tilt adjustment mechanism to correct the input tilt by comparing these data values ​​with the determined EPS edge reference value.

[0027] Specifically, the EPC roller may be positioned at a predetermined interval in front of the determined installation position of the EPS.

[0028] In one implementation, the controller can calculate the difference between the average of the initial data values ​​in the determined EPS edge position value data and the determined EPS edge reference value, and define the difference as a logic value; the logic values ​​of each electrode can be averaged to obtain an average logic value when inputting electrodes a predetermined number of times; and the input tilt can be corrected for each predetermined number of electrode inputs in response to the magnitude of the average logic value.

[0029] As a specific example, in the electrode tilt correction device, the correction period can be changed according to the magnitude of the absolute value of the average logic value; and the input tilt can be corrected by a predetermined correction value for each correction period.

[0030] In another embodiment, in the electrode skew correction device, the value obtained by multiplying the difference by a predetermined correction coefficient can be defined as a logical value, the correction coefficient reflecting the measurement error of the determined EPS caused by unexpected variables.

[0031] Specifically, the correction coefficient can be determined differently depending on the magnitude of the average logic value.

[0032] As another aspect of the invention, a method for correcting electrode skew during the conveying of electrodes to be wound onto a core to form a jelly roll electrode assembly includes: when an electrode input via an input jig reaches a predetermined EPS located before the core in an EPC unit, measuring the edge position of the electrode via the predetermined EPS to measure a predetermined EPS edge position value; controlling the edge position of the electrode via feedback from the EPC unit such that the predetermined EPS edge position value is consistent with a predetermined predetermined EPS edge reference value; obtaining predetermined EPS edge position value data when, via feedback control from the EPC unit, the predetermined EPS edge position value converges over time to the predetermined EPS edge reference value; and correcting the input tilt by selecting data values ​​from the predetermined EPS edge position value data that vary due to the input tilt of the input jig, and by comparing these data values ​​with the predetermined EPS edge reference value.

[0033] As a specific method for correcting electrode skew, the determined EPS edge position value data that changes over time can be obtained by measuring a predetermined number of times at regular time intervals until it converges to the determined EPS edge reference value; and the data value that changes due to the input tilt can be the initial data value among the determined EPS edge position value data.

[0034] In the method for correcting electrode skew, during the feedback control process of comparing with the determined EPS edge reference value, the difference between the average value of the initial data values ​​in the determined EPS edge position value data and the determined EPS edge reference value can be calculated, the difference is defined as a logic value, and the input skew can be corrected in response to the magnitude of the logic value.

[0035] As an example, in a method for correcting electrode skew, the logic values ​​of each electrode can be averaged to obtain an average logic value when the electrode is input a predetermined number of times; and the input skew can be corrected for each predetermined number of electrode inputs in response to the magnitude of the average logic value.

[0036] Specifically, the input skew can be corrected by changing the correction period based on the magnitude of the absolute value of the average logic value.

[0037] As a specific example, the initial data value could be the data value obtained by measuring EPS one to five times.

[0038] As an example, the input tilt can be corrected by a predetermined correction value for each correction cycle.

[0039] Specifically, when the sign of the average logic value is positive (+), a predetermined correction value can be subtracted from the input tilt; when the sign of the average logic value is negative (-), a predetermined correction value can be added to the input tilt.

[0040] As another example, in the method for correcting electrode skew of the present invention, the value obtained by multiplying the difference by a predetermined correction coefficient can be defined as a logic value, the correction coefficient reflecting the measurement error of the determined EPS due to unexpected variables; and the input tilt can be corrected in response to the magnitude of the logic value.

[0041] Specifically, the correction coefficient can be determined differently depending on the magnitude of the average logic value.

[0042] Beneficial effects

[0043] According to the present invention, by stably inputting the electrode into the winding core, the skewness defect caused by overshoot or noise during electrode input can be improved.

[0044] Therefore, since the edge position sensor (EPS) data during electrode input can be stabilized and the deviation of the initial EPS data can be reduced, the advantage is that the quality of the electrode assembly can be stabilized by improving the skew defects and skew deviations caused by electrode input instability. Attached Figure Description

[0045] Figure 1 This is a schematic diagram illustrating a conventional electrode skew correction device and correction method utilizing an End-Edge Position Control (EPC) unit.

[0046] Figure 2 This is a schematic diagram illustrating the impact of input instability when skew is corrected by the final EPC unit.

[0047] Figure 3 It is a graph illustrating the change of edge position values ​​of the edge position sensor (EPS) over time when the edge position of the control electrode is fed back through the final EPC unit.

[0048] Figure 4 This is a schematic diagram illustrating the electrode misalignment correction device according to the present invention.

[0049] Figure 5 This is a flowchart illustrating the sequence of the method for correcting electrode misalignment according to the present invention.

[0050] Figure 6 This is a flowchart illustrating the sequence of feedback control for correcting input tilt according to an embodiment of the present invention.

[0051] Figure 7 This is a flowchart illustrating the sequence of feedback control for correcting input tilt according to another embodiment of the present invention.

[0052] Figure 8 This is related to the diagram and logic value calculation process according to the present invention. Figure 7 A schematic diagram of the feedback control process.

[0053] Figure 9 It is a graph illustrating the state in which the EPS edge position value becomes stable over time when the input tilt is corrected to a predetermined correction value using the skew correction method of the present invention.

[0054] Figure 10 It is a graph related to the determination of the EPS edge position value after feedback control is completed by the method of correcting skewness of the present invention.

[0055] Figure 11 This is a graph illustrating the deviation of the initial EPS edge position value under feedback control using the skew correction method of the present invention. Detailed Implementation

[0056] The invention will now be described in detail with reference to the accompanying drawings. The terms and words used in this specification and claims should not be construed as limited to common or dictionary terms, but rather should be interpreted in a meaning and concept consistent with the technical scope of the invention, based on the principle that the inventors can appropriately define the concepts of the terms in order to best describe their invention.

[0057] In this application, it should be understood that terms such as "comprising" or "having" are intended to indicate the presence of the described features, quantities, steps, operations, components, parts, and / or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, and / or combinations thereof. Furthermore, when a portion of a layer, film, region, plate, etc., is referred to as being "on" another portion, this includes not only the case where the portion is "directly" "on" the other portion, but also the case where there is an additional portion between them. On the other hand, when a portion of a layer, film, region, plate, etc., is referred to as being "below" another portion, this includes not only the case where the portion is "directly" "below" the other portion, but also the case where there is an additional portion between them. Additionally, the term "on" in this application can include both lower and upper portions.

[0058] The present invention will be described in detail below.

[0059] Figure 3 It is a graph illustrating the change over time of the edge position value of the edge position sensor (EPS) when the edge position of the control electrode is fed back through the final edge position control (EPC) unit.

[0060] exist Figure 1 The text describes a situation where the edge position of electrode 1 is measured in the final EPS determination 32 of the final EPC unit 30, and the skew is corrected by adjusting the edge position of the electrode using the EPC roller 31 of the final EPC unit 30, so that the edge position of the electrode is consistent with the determined EPS edge reference value. However, even if the skew is corrected by the final EPC unit 30, the edge position of the electrode does not directly reach the determined EPS edge reference value A, but continues to travel to the determined EPS 32. Therefore, the edge position values ​​of the electrode continuously measured at the EPS position (hereinafter referred to as "determined EPS edge position values") are as follows: Figure 3 As shown, it gradually converges to a defined EPS edge reference value over time.

[0061] Figure 3 The diagram illustrates the process of measuring a total of 50 EPS data points using a predetermined procedure (program name 'BOIS') to determine the measurement edge position in EPS 32 until convergence to the determined EPS edge reference value A. Since the BOIS program only transmits the even-numbered data points of the EPS data, as shown... Figure 3 As shown, procedurally, a total of 25 measurements were taken to determine the EPS edge location value until convergence to the determined EPS edge reference value A. Furthermore, Figure 3 The X-axis represents the number of measurements taken or the measurement sequence number taken at regular time intervals until the determined EPS edge position value converges to the determined EPS edge reference value A. The Y-axis represents the determined EPS edge position value as the electrode position measured by the determined EPS at each measurement sequence number.

[0062] like Figure 3 As shown, the determined EPS edge location value fluctuates significantly (decreases) in measurement sequences 1 to 3, then exhibits a slight oscillation flow and gradually converges to the determined EPS edge reference value A (e.g., 0.80 mm). Figure 2As shown, the initial data values ​​for determining the EPS edge position fluctuate significantly due to overshooting during electrode input. That is, when the electrode is input, the input clamp rollers of the input clamp 10 may tilt, resulting in an incorrectly set input tilt angle for the electrode, or the electrode 1 may oscillate left and right during input and become misaligned due to unexpected input. Therefore, even after correction by the final EPC unit 30, the initial data for determining the EPS edge position measured at the EPS location changes considerably. Figure 3 As shown in the diagram. Therefore, when electrode 1 is input to core 60 and the initial data value does not fluctuate significantly, the skewness defects caused by overshoot or unexpected input instability, as described above, can be reduced. Based on this, the inventors selected data values ​​that fluctuate due to the input tilt related to the electrode input from the EPS position value data, and improved the skewness defects by correcting the tilt of the input fixture 10 through feedback control by comparing these data values ​​with the EPS edge reference value A.

[0063] Figure 4 This is a schematic diagram illustrating the electrode misalignment correction device 100 according to the present invention.

[0064] In this invention, with Figure 1 The same components as those in a conventional skew correction device are indicated by the same reference numerals.

[0065] This invention is based on feedback control of the final EPC unit 30, and therefore includes the EPC unit 30 as described in related art. That is, the skew correction device 100 of this invention includes an EPC unit 30, which is equipped with a determining EPS 32 and an EPC roller 31. The determining EPS 32 is positioned before the core 60 and determines the edge position of the electrode 1, recording this edge position as a determined EPS edge position value. The EPC roller 31 adjusts the edge position of the electrode so that the edge position of the electrode is consistent with the determined EPS edge reference value A.

[0066] In addition to the EPC unit 30, the present invention also includes an input tilt adjustment mechanism 70 for adjusting the input tilt of the input fixture 10. The input tilt adjustment mechanism 70 adjusts the input tilt of the input fixture, i.e., the input tilt of the electrodes input to the input fixture, for example, by adjusting the tilt of the input fixture roller or shaft disposed in the input fixture 10 in the left-right direction. One or both ends of the roller shaft may be connected to another linearly moving shaft and associated with the linear movement of that other shaft to tilt the roller shaft. The linearly moving shaft may be connected to a predetermined drive unit such as a motor for linear movement. That is, the tilt of the roller shaft can be adjusted by connecting a conversion mechanism (e.g., a ball screw and ball nut) and the linearly moving shaft and moving the linearly moving shaft by driving a motor, the conversion mechanism converting rotational motion into linear motion by driving a motor, etc. Alternatively, a pneumatic cylinder in which the piston can move linearly from the cylinder body by gas pressure can be used to connect the piston and the roller shaft, so that the tilt of the roller shaft can be adjusted by the linear movement of the piston. Since such linear movement mechanisms are well known in the mechanical field, their detailed description will be omitted. Importantly, as long as the tilt of the input clamp 10 can be adjusted by moving the input clamp roller or shaft, the mechanical or electronic structure of the tilt adjustment mechanism does not need to be particularly restricted.

[0067] The present invention includes a controller 40 that controls an EPC unit 30 and an input tilt adjustment mechanism 70 of an input fixture. The controller 40 obtains a determined EPS edge position value from the EPS 32 of the EPC unit 30 and feeds back the edge position of the control electrode 1 so that the determined EPS edge position value is consistent with a determined EPS edge reference value A. Furthermore, the input tilt adjustment mechanism 70 is fed back to correct the input tilt by comparing the time-varying value of the determined EPS edge position value obtained in the feedback process with the determined EPS edge reference value A.

[0068] The EPC roller 31 can be installed at a predetermined interval (P: for example, 125 mm from the core) in front of the determined installation position of the EPS 32 (Q: for example, 100 mm from the core). When the position of electrode 1 measured in the EPS 32 differs from the determined EPS edge reference value A, the controller 40 causes the EPC roller 31 to adjust the position of electrode 1 at the predetermined interval in front of the determined EPS 32. Therefore, when an electrode moves continuously to the determined EPS 32, the adjusted position of electrode 1 can be subsequently measured in the determined EPS 32.

[0069] The skew correction device 100 of the present invention includes an input tilt adjustment mechanism 70 and a controller 40. The controller 40 can correct the input tilt of the input fixture 10 by controlling the feedback of the EPC unit 30 and the input tilt adjustment mechanism 70, thereby improving the input stability of the electrode 1 input to the winding core 60 and reducing the occurrence of unexpected skew defects.

[0070] In this invention, to improve the input stability of electrode 1, the determined EPS edge position value data, which is affected by the input tilt, is compared with the determined EPS edge reference value A, so that the input tilt is corrected according to the tilt correction device 100. Based on the comparison, the controller 40 feeds back to control the input tilt adjustment mechanism 70, and as... Figure 4 The adjustment of the input tilt shown is used to correct the electrode input direction. Figure 4 The B direction in the input direction can reduce skew caused by unexpected input defects.

[0071] The present invention further provides a method for correcting skew when conveying electrodes to be wound on a core 60 to form a jelly roll electrode assembly.

[0072] Figure 5 This is a flowchart illustrating the sequence of the method for correcting electrode misalignment according to the present invention.

[0073] As shown in the figure, firstly, in step (a), when the electrode 1 input by the input fixture 10 reaches the determined EPS 32 of the EPC unit 30 located before the core, the edge position of the measured electrode is determined by the determined EPS 32, and thus the edge position value of the determined EPS is measured.

[0074] Then, in step (b), the edge position of the control electrode is fed back through the EPC unit 30 so that the determined EPS edge position value is consistent with the predetermined determined EPS edge reference value A.

[0075] Next, in step (c), the EPS edge position value data is obtained when the EPS edge position value converges to the EPS edge reference value A as determined by the feedback control of EPC unit 30 over time.

[0076] Next, in step (d), data values ​​that vary due to the input tilt are selected from the data of determined EPS edge position values, and feedback control is performed by comparing these data values ​​with the determined EPS edge reference value A, so that the input tilt is corrected in step (e).

[0077] The time-varying EPS edge location value can be obtained by measuring a predetermined number of times at regular time intervals until it converges to a defined EPS edge reference value A. For example... Figure 3As shown, for example, data to determine the edge location of EPS can be obtained through 50 measurements. Figure 3 As shown, in the position value data, the data values ​​that change due to the input tilt are the initial change data values ​​in the EPS edge position value data. For example, when measuring 50 times to determine the EPS edge position value until converging to the EPS edge reference value, the initial data values ​​could be the data values ​​measured 1 to 5 times by determining EPS 32.

[0078] Embodiments of the present invention

[0079] In the method for correcting skew of the present invention, the input skewness is adjusted by feedback control that compares the initial data value with the determined EPS edge reference value A. Therefore, a specific implementation of the feedback control will be described below.

[0080] (First Implementation)

[0081] Figure 6 This is a flowchart illustrating the sequence of feedback control for correcting the input tilt of an input fixture according to an embodiment of the present invention.

[0082] First, in step (d1), the average of the initial data values ​​in the data for determining the EPS edge location is compared with the EPS edge reference value A. Comparing the average of the initial data values ​​to the EPS edge reference value A, rather than comparing individual values ​​from the initial data set, more effectively reflects the impact of input instability. Therefore, for example, calculating... Figure 3 The difference between the average of the (initial) EPS edge position values ​​determined by measurement sequences 1 to 5 (1 to 3 in the Bois program) and the EPS edge reference value A. This difference is defined as a predetermined logic value (X) used for feedback control. logic ), and is expressed as Equation 1 described below. A large logic value indicates a large instability at the input electrode, therefore, the input tilt of the input fixture 10 can be corrected in response to the magnitude of the logic value.

[0083] X logic = [(Average value of EPS edge position values ​​No.1 to No.5) - EPS edge reference value] ---------- Equation 1

[0084] In this embodiment, electrode skew is corrected by averaging the logic values ​​when multiple electrodes are input, which improves the reliability of skew correction and is a further improvement over using the logic value when a single electrode is input. That is, in step (d2), the average logic value (average X) of the logic values ​​of each electrode is calculated after a predetermined number of input electrodes. logic(See Equation 2 described below).

[0085] The average X when the input electrode is applied n times logic =X1+X2+…+X n-1 +X n / n------ Equation 2

[0086] The average logic value is the average of the logic values ​​when inputting to multiple electrodes, thus better representing instability at input electrodes. Therefore, instability at input electrodes can be addressed more effectively by correcting the input skew for each predetermined number of electrode inputs in response to the magnitude of the average logic value.

[0087] Furthermore, it is more preferable to perform correction by adjusting the correction period based on the magnitude of the average logic value. A large average logic value after a predetermined number of input electrode cycles indicates significant instability during input electrode operation. Therefore, when the average logic value is large, the correction period can be reduced to perform correction quickly, and when the average logic value is small, the correction period can be extended. Figure 4 In this context, the EPS edge position value is determined by a negative (-) value when tilting to the left and a positive (+) value when tilting to the right. Therefore, the sign of the average logic value can also be represented as negative or positive, and correction can be performed by changing the correction period based on the magnitude of the absolute value of the average logic value.

[0088] The following is an example of a case where correction is performed by changing the correction period based on the magnitude of the absolute value of the average logic value.

[0089] <Average X at 5 input electrodes> logic >

[0090] Average X logic =X1+X2+X3+X4+X5 / 5

[0091] |Average X logic |≥0.200→ Correct input tilt 5 times per input electrode

[0092] <Average X when inputting electrodes 10 times logic >

[0093] Average X logic =X1+X2+…+X9+X 10 / 10

[0094] 0.100 ≤ |averageX logic |<0.200→ Correct input tilt 10 times per input electrode

[0095] <Average X when inputting electrodes 15 times> logic >

[0096] Average Xlogic =X1+X2+…+X 14 +X 15 / 15

[0097] 0.050 ≤ |average X logic |<0.100→ Input tilt is corrected 15 times per input electrode.

[0098] <Average X when inputting electrodes 20 times> logic >

[0099] Average X logic =X1+X2+…+X 19 +X 20 / 20

[0100] 0.025 ≤ |averageX logic |<0.050→ Correct input tilt 20 times per input electrode

[0101] <Average X when inputting electrodes 25 times> logic >

[0102] Average X logic =X1+X2+…+X 24 +X 25 / 25

[0103] |Average X logic |<0.025→ Do not perform input tilt correction

[0104] When calculating the average logic value in step (d2), the input tilt can be corrected to a predetermined correction value (step (e)) by changing the correction period according to the magnitude of the average logic value. This correction value can be given as a default value, which is a numerical unit that can be used to correct the input tilt based on the magnitude of the average logic value within the range where the input tilt can be adjusted. For example, the input tilt can be corrected by a correction value of 0.01. A larger correction value indicates a larger magnitude of tilt correction in a single correction, while a smaller correction value indicates a smaller magnitude of tilt correction in a single correction. When the correction value is small, the magnitude of roller tilt correction in a single correction is smaller, but the input tilt can be adjusted more precisely.

[0105] Furthermore, since the average logic value has a sign, an input skew correction value is applied in the opposite direction to the sign. For example, when the sign of the average logic value is positive, the input skew is corrected by subtracting a predetermined correction value (e.g., 0.01), and when the sign of the average logic value is negative, the input skew is corrected by adding a predetermined correction value (e.g., 0.01). Therefore, the magnitude of the average logic value can be reduced.

[0106] Subsequently, as steps (d1) through (e) are repeated in step (f), feedback correction is performed in which the average logic value decreases sequentially for the multiple electrodes input through input fixture 10. When this feedback correction is repeated and the final average logic value is less than a predetermined value, since the electrode input instability is completely resolved and the input tilt enters a stable range, no additional correction of the input tilt is required. That is, when the average X logic When the absolute value is less than 0.025, the input tilt has entered a stable range, so there is no need to correct the input tilt. Correcting the input tilt within this range will actually increase input instability.

[0107] (Second Implementation)

[0108] Figure 7 This is a flowchart illustrating the sequence of feedback control for correcting input tilt according to another embodiment of the present invention.

[0109] This implementation method uses the logical value X. logic The definition differs from that of the first implementation method.

[0110] In this embodiment, to obtain the logic value, the value obtained by multiplying the logic value of Embodiment 1 (the difference between the average of the initial data values ​​and the baseline value for determining the EPS edge) by a predetermined correction coefficient reflecting the measurement error in determining the EPS due to unexpected variables is defined as the logic value. Electrodes are continuously conveyed from the electrode production and winding line, thereby being conveyed to the core and wound onto the core to form a jelly roll electrode assembly. During this process, oscillations or overshoots of unknown cause may occur. Alternatively, sensors such as EPS may be contaminated, or, in extreme cases, the electrodes may separate from the core, thus resulting in errors in determining the EPS measurement value. When the measurement error in determining the EPS due to this unexpected variable is not considered, the measurement error inevitably generated during feedback control may not be reflected, and thus the impact of input instability may not be accurately assessed. Therefore, in the second embodiment, the value obtained by multiplying by a predetermined correction coefficient reflecting the measurement error in determining the EPS due to this unexpected variable is used as the logic value. For example, when the correction coefficient is 1, it may indicate a normal production line operation in which unexpected variables may occur. On the other hand, when the correction coefficient is less than 1, for example, 0.6, it reflects stable operation without unexpected variables. When the logic value or average logic value is less than the predetermined value even under stable operation, it can be determined that the input stability has entered the stable range, and in this case, it is no longer necessary to correct the input skew.

[0111] In summary, when the correction coefficient is P logic In step (d1)', the logic value X of this embodiment...logic It can be defined as Equation 3 as described below.

[0112] X logic = [(Average value of EPS edge position values ​​No.1 to No.5) - EPS edge reference value] × P logic ----Formula 3

[0113] Then, in step (d2), the average logic value (average X) of the logic value of each electrode is calculated by averaging the logic values ​​of each electrode a predetermined number of times. logic (See Equation 4 described below).

[0114] The average X when the input electrode is applied n times logic ={X1+X2+…+X n-1 +X n / n}×P logic -- Formula 4

[0115] Furthermore, it is more preferable to perform the correction by changing the correction period according to the magnitude of the average logic value. An example of performing correction for each predetermined number of electrode inputs by changing the correction period according to the magnitude of the absolute value of the average logic value is as follows.

[0116] The average X when the input electrode is used 5 times logic >

[0117] Average X logic ={X1+X2+X3+X4+X5 / 5}×P logic

[0118] P logic =1.0

[0119] |Average X logic |≥0.200→ Correct input tilt 5 times per input electrode

[0120] <Average X when inputting electrodes 10 times logic >

[0121] Average X logic ={X1+X2+…+X9+X 10 / 10}×P logic

[0122] P logic =1.0

[0123] 0.100 ≤ |averageX logic |<0.200→ Correct input tilt 10 times per input electrode

[0124] <Average X when inputting electrodes 15 times> logic >

[0125] Average X logic ={X1+X2+…+X 14 +X 15}×P logic

[0126] P logic =1.0

[0127] 0.050 ≤ |average X logic |<0.100→ Input tilt is corrected 15 times per input electrode.

[0128] <Average X when inputting electrodes 20 times> logic >

[0129] Average X logic ={X1+X2+…+X 19 +X 20}×P logic

[0130] P logic =1.0

[0131] 0.025 ≤ |averageX logic |<0.050→ Correct input tilt 20 times per input electrode

[0132] <Average X when inputting electrodes 25 times> logic >

[0133] Average X logic ={X1+X2+…+X 24 +X 25 / 25}×P logic

[0134] P logic =0.6

[0135] |Average X logic |<0.025→ Do not perform input tilt correction

[0136] When calculating the average logic value in step (d2), the input skew can be corrected by a predetermined correction value (step (e)) by changing the correction period according to the magnitude of the average logic value. For example, the input skew can be corrected by a correction value of 0.01. When the sign of the average logic value is positive, the input skew is corrected by subtracting the predetermined correction value (e.g., 0.01), and when the sign of the average logic value is negative, the input skew is corrected by adding the predetermined correction value (e.g., 0.01). Therefore, the magnitude of the average logic value can be reduced.

[0137] Subsequently, since steps (d1)' to (e) are repeated in step (f), feedback correction is performed in which the average logic value decreases sequentially for the multiple electrodes input through input fixture 10. When this feedback correction is repeated and the final average logic value is less than a predetermined value, since the electrode input instability is completely resolved and the input tilt enters a stable range, no additional correction of the input tilt is required. That is, when the average X logic When the absolute value of the input skew is less than 0.025, the input skew has entered a stable range, so no correction is needed. Correcting the input skew within this range actually increases input instability. In the first embodiment, where the correction factor due to unexpected variables is not considered, there exists a situation where, even when the system is stable due to few unexpected variables, the input skew is mechanically corrected based on the average logic value. In this case, input instability actually increases due to the input skew correction. Therefore, as described above, when the absolute value of the average logic value is less than 0.025 by multiplying the average logic value obtained from 25 input electrode cycles by the correction factor 0.6, since the system has entered a stable range, no further correction is performed. In this case, calculating the average logic value by multiplying by the correction factor 1 would meaninglessly repeat the input skew correction. Therefore, the key point of this embodiment is that by setting a consistent standard (a correction factor of 0.6) for a stable range without unexpected variables and establishing the ultimate goal of feedback control, input stability can be reliably improved.

[0138] Figure 8 This more clearly illustrates the steps related to logical value calculation according to the present invention. Figure 7 A schematic diagram of the feedback control process in the second embodiment.

[0139] like Figure 8 As shown, for example, average logic values ​​are obtained from initial EPS data of electrodes (J / R1, J / R2, ... J / R24, J / R25) used in the manufacture of 25 jelly roll (J / R) electrode assemblies. Furthermore, these average logic values ​​are multiplied by a predetermined correction factor (e.g., 1.0 or 0.6).

[0140] The correction cycle is changed according to the magnitude of the absolute value of the average logic value that reflects the correction coefficient (e.g., once every 5 inputs, 10 inputs, 15 inputs, and 20 inputs) to adjust the input tilt by adding or subtracting a predetermined correction value (0.01).

[0141] When the average logic value calculated from the initial logic value multiplied by the correction factor is less than 0.025 (when multiplied by the correction factor is 0.6), the purpose of feedback control is achieved, and there is no need to correct the input tilt. Otherwise, repeat the above process to calculate the secondary logic value.

[0142] Figure 9 This is a graph illustrating the state in which the EPS edge position value stabilizes over time when the tilt (input tilt) of the input fixture 10 is corrected to a predetermined correction value using the skew correction method of the present invention.

[0143] Figure 9 Figure (a) illustrates the change in EPS data over time (number of measurements) when the input tilt is adjusted by a correction value of 0.01 and corrected from an initial input tilt of 0.40 to a final input tilt of 0.25 (a total of 15 corrections). As shown in the figure, with repeated corrections, the deviation between the initial EPS data and the baseline value used to determine the EPS edge can be observed to decrease.

[0144] Figure 9 (b) illustrates the process of adjusting the input skew from an initial input skew of 0.27 to a final input skew of 0.20 using a correction value of 0.01 (a total of 7 corrections). Figure 9 (c) illustrates the process of adjusting the input skew from an initial input skew of 0.25 to a final input skew of 0.20 using a correction value of 0.01 (a total of 5 corrections). Figure 9 As shown in (c), when the input skewness becomes 0.20, it can be seen that the initial EPS data converges to a value close to the defined EPS edge reference value, thus removing noise through a stable input.

[0145] Figure 10 This is a graph related to the determined EPS edge position value after feedback control is completed using the skew correction method of this invention. This is related to... Figure 9 The curve is the same when the input tilt is controlled by feedback to 0.20. Figure 10 In the meantime, almost identical to the mid-term and late-term data, the initial EPS data is close to the baseline value that determines the EPS edge, thus demonstrating a significant improvement in input stability.

[0146] Figure 11 This is a graph illustrating the deviation of the initial EPS edge position value under feedback control using the skew correction method of this invention. Initial EPS data without feedback control is shown in red, and initial EPS data with feedback control is shown in blue. Figure 11 As shown in (a), it can be seen that the deviation of the initial EPS data is significantly reduced when feedback control is performed on thousands of input electrodes, compared to the case where no feedback control is performed. Figure 11(b) illustrates the deviation in a simplified form. It can be seen that when a large number of electrodes are controlled by feedback, the deviation of the initial EPS data is close to 0.00, which greatly improves the input stability and also greatly reduces the deviation of the electrode position caused by the input.

[0147] The present invention has been described in more detail above with reference to the accompanying drawings, examples, etc. However, since the configurations described in the drawings, embodiments, etc., in this application are only one embodiment of the present invention and do not represent all the technical spirit of the present invention, it should be understood that various equivalents and modifications may exist when this application is filed.

[0148] (Reference number)

[0149] 1: Electrode

[0150] 1a: Skewed traveling electrode

[0151] 10: Input Fixture

[0152] 20: Cutter

[0153] A: Determine the EPS edge benchmark value

[0154] 30: EPC Unit

[0155] 31: EPC Roller

[0156] 32: Determine EPS

[0157] 40: Controller

[0158] 50: Final roll

[0159] 60: Roll core

[0160] 70: Input tilt adjustment mechanism for input fixture

[0161] 100: Skew correction device.

Claims

1. An electrode skew correction device, said electrode skew correction device being used to correct skew during the conveying of electrodes to be wound onto a core to form a jelly roll electrode assembly, said electrode skew correction device comprising: An input tilt adjustment mechanism for an input fixture, the input fixture being configured to input the electrode into the winding core; An edge position control (EPC) unit is provided with an edge position sensor (EPS) and an EPC roller. The EPS is located before the core to measure the edge position of the electrode as the determined EPS edge position value. The EPC roller is configured to adjust the edge position of the electrode to match the determined EPS edge reference value. as well as A controller configured to control the EPC unit and the input tilt adjustment mechanism. The controller provides feedback control over the edge position of the electrode, ensuring that the determined EPS edge position value matches the determined EPS edge reference value; and obtains determined EPS edge position value data when, through the feedback control, the determined EPS edge position value converges to the determined EPS edge reference value over time. The system selects data values ​​from the determined EPS edge position value data that vary due to the input tilt of the input fixture, and uses these data values ​​to provide feedback control to the input tilt adjustment mechanism to correct the input tilt by comparing them with the determined EPS edge reference value. The determined EPS edge position value data is obtained by measuring a predetermined number of times at regular time intervals until it converges to the determined EPS edge reference value, and the data value that changes due to the influence of the input tilt is the initial data value in the determined EPS edge position value data.

2. The electrode skew correction device according to claim 1, wherein the EPC roller is disposed at a predetermined interval in front of the determined installation position of the EPS.

3. The electrode tilt correction device according to claim 1, wherein the controller calculates the difference between the average value of the initial data values ​​in the determined EPS edge position value data and the determined EPS edge reference value, and defines the difference as a logic value; averages the logic values ​​of each electrode to obtain an average logic value when inputting electrodes a predetermined number of times; and corrects the input tilt for each predetermined number of electrode inputs in response to the magnitude of the average logic value.

4. The electrode misalignment correction device according to claim 3, wherein: The correction period is changed according to the magnitude of the absolute value of the average logic value; and For each correction cycle, the input tilt is corrected by a predetermined correction value.

5. The electrode misalignment correction device according to claim 3, wherein: The value obtained by multiplying the difference by a predetermined correction factor is defined as a logical value, which reflects the measurement error of the determined EPS due to unexpected variables.

6. The electrode skew correction device according to claim 5, wherein the correction coefficient is determined differently depending on the magnitude of the average logic value.

7. A method for correcting electrode skew during the conveying of electrodes to be wound onto a core to form a jelly roll electrode assembly, the method comprising: When the electrode input through the input fixture reaches the determined EPS of the EPC unit located before the winding core, the edge position of the electrode is measured through the determined EPS to measure the edge position value of the determined EPS. The edge position of the electrode is controlled by feedback from the EPC unit so that the determined EPS edge position value is consistent with the predetermined determined EPS edge reference value. Obtain EPS edge position value data when the EPS edge position value converges to the EPS edge reference value over time through feedback control of the EPC unit; as well as The input tilt is corrected by feedback control that selects data values ​​from the determined EPS edge position value data that vary due to the input tilt of the input fixture, and compares these data values ​​with the determined EPS edge reference value. The determined EPS edge position value data is obtained by measuring a predetermined number of times at regular time intervals until it converges to the determined EPS edge reference value, and the data value that changes due to the influence of the input tilt is the initial data value in the determined EPS edge position value data.

8. The method according to claim 7, wherein, In the feedback control process of comparing with the determined EPS edge reference value, the difference between the average of the initial data values ​​in the determined EPS edge position value data and the determined EPS edge reference value is calculated, the difference is defined as a logic value, and the input tilt is corrected in response to the magnitude of the logic value.

9. The method according to claim 8, wherein: The logic value of each electrode is averaged to obtain the average logic value after a predetermined number of input electrodes. and In response to the magnitude of the average logic value, the input tilt is corrected for each predetermined number of electrode inputs.

10. The method of claim 9, wherein the input skew is corrected by changing the correction period according to the magnitude of the absolute value of the average logic value.

11. The method of claim 8, wherein the initial data value is obtained by determining the data values ​​of the first to fifth EPS measurements.

12. The method of claim 10, wherein the input tilt is corrected by a predetermined correction value for each correction cycle.

13. The method of claim 12, wherein when the sign of the average logic value is positive (+), a predetermined correction value is subtracted from the input skew, and when the sign of the average logic value is negative (-), a predetermined correction value is added to the input skew.

14. The method according to claim 8, wherein: The value obtained by multiplying the difference by a predetermined correction factor is defined as a logical value, the correction factor reflecting the measurement error in determining EPS due to unexpected variables; and The input skew is corrected in response to the magnitude of the logic value.

15. The method of claim 14, wherein: The logic values ​​of each electrode are averaged to obtain an average logic value after a predetermined number of input electrode cycles; and In response to the magnitude of the average logic value, the input tilt is corrected for each predetermined number of electrode inputs.

16. The method of claim 15, wherein the input skew is corrected by changing the correction period according to the magnitude of the absolute value of the average logic value.

17. The method of claim 16, wherein the input tilt is corrected by a predetermined correction value for each correction cycle.

18. The method of claim 15, wherein the correction coefficient is determined differently depending on the magnitude of the average logic value.

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