Apparatus and method for measuring thickness of electrode plate

Abstract

An apparatus and method for measuring the thickness of an electrode plate capable of measuring the thickness of an active material coating layer formed on the electrode plate prior to drying the electrode plate. The apparatus for measuring the thickness of the electrode plate comprises: a sensor module configured to detect the thickness of the electrode plate upstream of a drying furnace; and a processor connected to the sensor module and configured to detect a thickness of the electrode plate in a width direction through the sensor module, calculate an active material coating thickness based on the thickness of the electrode plate, and compensate the active material coating thickness based on a measurement error caused by thermal deformation of the sensor module.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to an apparatus and method for measuring the thickness of an electrode plate. Background Art

[0002] In recent years, with the development of mobile technology and the increasing demand for it, the demand for secondary batteries as an energy source has increased rapidly, and research has been conducted on batteries capable of meeting various requirements. For example, lithium secondary batteries with high energy density, discharge voltage, and output stability are required.

[0003] Generally, a secondary battery is manufactured by applying an active material to the surface of a current collector to form a cathode plate and an anode plate (hereinafter, generally referred to as an electrode plate), disposing a separator therebetween to form an electrode assembly, and installing the electrode assembly in a cylindrical or polyhedral metal can or an aluminum laminated sheet bag-shaped case. Then, the secondary battery is completed by injecting a liquid electrolyte into the electrode assembly to embed the electrode plate in the electrolyte or by using a solid electrolyte.

[0004] For such a secondary battery, it is suitable to ensure the battery performance of the same quality and to sufficiently control the thickness of the electrode plate on the surface of the current collector.

[0005] Generally, the thickness of the electrode plate is measured by a radiation device located behind a drying furnace. However, this technique may have a problem that coating failures cannot be quickly inspected.

[0006] It should be noted that this section is only intended to provide a better understanding of the background of the present disclosure, and thus may include information that is not necessarily prior art. Summary of the Invention

[0007] The present disclosure provides an apparatus and method for measuring the thickness of an electrode plate, which can measure the thickness of an active material coating layer formed on the electrode plate before the electrode plate is dried by a dryer.

[0008] The above and other aspects of the present disclosure will become apparent from the following description of embodiments of the present disclosure.

[0009] According to an aspect of the present disclosure, there is provided an apparatus for measuring the thickness of an electrode plate, the apparatus including: a sensor module configured to detect the thickness of the electrode plate upstream of a drying furnace; and a processor connected to the sensor module and configured to detect the thickness of the electrode plate in a width direction through the sensor module, calculate an active material coating thickness based on the thickness of the electrode plate, and compensate the active material coating thickness based on a measurement error caused by thermal deformation of the sensor module.

[0010] The sensor module may include: a first sensor module configured to measure the distance to the electrode plate above the electrode plate; and a second sensor module configured to measure the distance to the electrode plate below the electrode plate, and the first sensor module and the second sensor module are configured to be synchronously controlled.

[0011] The processor may be configured to calculate the active material coating thickness by subtracting the thickness of the electrode plate measured before coating the active material from the thickness of the electrode plate detected by the sensor module.

[0012] The processor may be configured to detect the thickness of the electrode plate at a first position where the active material is not coated, and calculate the measurement error based on the thickness of the electrode plate at the first position.

[0013] The processor may be configured to calculate the measurement error at the first position by subtracting the thickness of the electrode plate measured at the first position before coating the active material from the thickness of the electrode plate at the first position.

[0014] The processor may be configured to perform interpolation based on the measurement error at the first position to calculate the measurement error at a second position coated with the active material.

[0015] The processor may be configured to compensate the active material coating thickness by subtracting the measurement error from the active material coating thickness.

[0016] The processor may be configured to send information about the active material coating thickness to an active material coating device configured to coat the electrode plate with the active material, such that the pump, valve, and slit die of the active material coating device are under feedback control.

[0017] The processor may be configured to determine whether a coating failure of the electrode plate occurs based on the active material coating thickness.

[0018] The processor may be configured to determine a target column among the columns of the active material coating layer on the electrode plate, and be configured to determine whether a coating failure occurs in the target column by repeating the process of determining whether a coating failure occurs in the target column while changing the target column.

[0019] The processor may be configured to calculate a first average value of the active material coating thickness for the target column, and determine that a coating failure occurs in the target column when there is a position in the target column where the active material coating thickness is less than or equal to a first threshold set based on the first average value.

[0020] The processor may be configured to determine whether a coating failure occurs in the target column by dividing the target column into multiple zones, determining a target zone among the multiple zones, and repeating the process of determining whether a coating failure occurs in the target zone while changing the target zone.

[0021] The processor may be configured to calculate a second average value of the active material coating thickness for the target area, and determine that a coating failure has occurred in the target area when there is a position in the target area where the active material coating thickness is less than or equal to a second threshold set based on the second average value.

[0022] According to one aspect of the present disclosure, a method for measuring the thickness of an electrode plate is provided, the method including: detecting the electrode plate thickness of the electrode plate in the width direction by a sensor module upstream of a drying furnace; calculating the active material coating thickness based on the electrode plate thickness; compensating the active material coating thickness based on a measurement error caused by thermal deformation of the sensor module.

[0023] Calculating the active material coating thickness may include subtracting the electrode plate thickness measured before coating the active material from the electrode plate thickness detected by the sensor module.

[0024] Calculating the measurement error may include detecting the electrode plate thickness at a first position where no active material is coated and calculating the measurement error based on the electrode plate thickness at the first position.

[0025] Calculating the measurement error may include subtracting the electrode plate thickness measured at the first position before coating the active material from the electrode plate thickness at the first position to calculate the measurement error at the first position.

[0026] Calculating the measurement error may include performing interpolation based on the measurement error at the first position to calculate the measurement error at a second position where the active material is coated.

[0027] Compensating the active material coating thickness may include subtracting the measurement error from the active material coating thickness to compensate the active material coating thickness.

[0028] The method may further include sending information about the active material coating thickness to an active material coating device configured to coat the electrode plate with the active material, such that the pump, valve, and slit die of the active material coating device are under feedback control.

[0029] According to one aspect of the present disclosure, the thickness of the active material coating layer formed on the electrode plate may be measured before drying the electrode plate by a dryer.

[0030] According to one aspect of the present disclosure, by compensating the measurement error caused by thermal deformation of the sensor module, the thickness of the active material coating layer formed on the electrode plate can be calculated more accurately.

[0031] According to one aspect of the present disclosure, stripe defects occurring during the process of coating the electrode plate with the active material slurry may be detected.

[0032] However, aspects of the present disclosure are not limited to those described above, and other aspects not mentioned will be clearly understood by those skilled in the art from the detailed description given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings of this specification illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the drawings:

[0034] Figure 1 is a block diagram of a device for measuring the thickness of an electrode plate;

[0035] Figure 2A and Figure 2B is a view of an electrode plate coated with an active material;

[0036] Figure 3 is a view of a sensor module;

[0037] Figure 4 is a view showing the thermal deformation of the sensor module;

[0038] Figure 5 is a flowchart showing a method for measuring the thickness of an electrode plate;

[0039] Figure 6A and Figure 6B is a view showing the process of calculating the coating thickness of the active material;

[0040] Figure 7 is a flowchart showing the process of calculating the measurement error;

[0041] Figure 8 is a view showing the process of calculating the measurement error;

[0042] Figure 9 is a flowchart showing the process of determining the occurrence of coating failure;

[0043] Figure 10 、 Figure 11 and Figure 12 is a view showing the process of determining the occurrence of coating failure;

[0044] Figure 13 is a flowchart showing the process of determining the occurrence of coating failure;

[0045] Figure 14 is a view showing the process of determining the occurrence of coating failure; and

[0046] Figure 15 is a diagram of an electrode plate coating device according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to the ordinary or dictionary meanings, but should be interpreted as meanings and concepts consistent with the technical idea of the present disclosure based on the principle that the inventor can be his / her own lexicographer to appropriately define the terms so as to best explain his / her invention.

[0048] The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure and do not represent all the technical ideas, aspects, and features of the present disclosure. Therefore, it should be understood that there can be various equivalents and modifications capable of replacing or modifying the embodiments described herein at the time of filing this application.

[0049] It will be understood that when an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or there can also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. For example, when a first element is described as being "coupled" or "connected" to a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0050] In the drawings, for clarity of illustration, the dimensions of various elements, layers, etc. may be exaggerated. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Further, in describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure". Expressions such as "at least one of..." and "any one of..." when following a list of elements modify the entire list of elements and not individual elements in the list. When phrases such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group consisting of A, B, and C", or "at least one selected from among A, B, and C" are used to specify a list of elements A, B, and C, the phrase can refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms "use", "using...", and "being used" can be considered to be synonymous with the terms "utilize", "utilizing...", and "being utilized", respectively. As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0051] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, first component, first region, first layer, or first section discussed below may be referred to as a second element, second component, second region, second layer, or second section without departing from the teachings of the exemplary embodiments.

[0052] For ease of description, spatial relationship terms such as "under", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It will be understood that, in addition to the orientation depicted in the figures, the spatial relationship terms are intended to encompass other different orientations of the device during use or operation. For example, if the device in the figures is flipped, an element described as "under" or "below" another element or feature will be oriented "above" or "over" the other element or feature. Thus, the term "under" can encompass both an upper and a lower orientation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relationship descriptive terms used herein should be interpreted accordingly.

[0053] When one or more embodiments can be implemented differently, a particular process order can be performed differently from the described order. For example, two consecutively described processes can be performed substantially simultaneously or can be performed in an order opposite to the described order.

[0054] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular form "a" is also intended to include the plural form unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0055] Furthermore, any numerical range disclosed and / or recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, the range "1.0 to 10.0" is intended to include all sub-ranges between the recited minimum value 1.0 and the recited maximum value 10.0 (and including the recited minimum value 1.0 and the recited maximum value 10.0), that is, all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit recited herein is intended to include all lower numerical limits subsumed therein, and any minimum numerical limit recited in this specification is intended to include all higher numerical limits subsumed therein. Accordingly, the applicant reserves the right to modify this specification (including the claims) to expressly recite any sub-ranges subsumed within the ranges expressly recited herein.

[0056] Referring to two compared elements, features, etc. as "the same" can mean that they are "substantially the same." Thus, the phrase "substantially the same" can include cases having a deviation considered low in the art (e.g., a deviation of 5% or less). In addition, when a certain parameter is said to be uniform within a given region, this can mean that it is uniform in terms of the average value.

[0057] Throughout the specification, unless otherwise stated, each element can be singular or plural.

[0058] When any element is said to be disposed (or positioned or located) "above (or below)" or "on (or under)" a component, it can mean that the any element is placed in contact with the upper (or lower) surface of the component, or it can mean that another component can be interposed between the component and any element disposed (or positioned or located) on (or under) the component.

[0059] In addition, it will be understood that when an element is referred to as being "coupled", "linked" or "connected" to another element, the element can be "coupled", "linked" or "connected" directly to each other, or there can be intervening elements therebetween, and the element can be "coupled", "linked" or "connected" to the other element through the intervening elements. In addition, when a component is referred to as being "electrically coupled" to another component, the component can be directly connected to the other component, or there can be intervening components therebetween such that the component and the other component are indirectly connected to each other.

[0060] Throughout the specification, when stating "A and / or B", it means A, B, or A and B, unless otherwise specified. That is, "and / or" includes any or all combinations of the recited items. When stating "C to D", it means C or more and D or less, unless otherwise specified.

[0061] In some embodiments, well-known structures and devices may be depicted in the drawings with respect to one or more functional blocks (e.g., block diagrams), units, and / or modules to avoid unnecessarily obscuring the various embodiments. Those skilled in the art will understand that such blocks, units, and / or modules are physically implemented by logic circuits, discrete components, microprocessors, hardwired circuits, storage elements, wire connections, and other electronic circuits. This can be formed using semiconductor-based manufacturing techniques or other manufacturing techniques. Blocks, units, and / or modules implemented by a microprocessor or other similar hardware can be programmed and controlled using software to perform the various functions discussed herein, and optionally can be driven by firmware and / or software. Additionally, each block, unit, and / or module can be implemented by dedicated hardware or a combination of dedicated hardware that performs some functions and a processor (e.g., one or more programmed microprocessors and associated circuits) that performs functions different from the functions of the dedicated hardware. Furthermore, in some embodiments, the blocks, units, and / or modules can be physically divided into two or more interacting discrete blocks, units, and / or modules without departing from the scope of the present disclosure. Additionally, in some embodiments, the blocks, units, and / or modules can be physically combined into more complex blocks, units, and / or modules without departing from the scope of the present disclosure.

[0062] Figure 1 is a block diagram of a device for measuring the thickness of an electrode plate, Figure 2A and Figure 2B is a view of an electrode plate coated with an active material, Figure 3 is a view of a sensor module.

[0063] Referring to Figure 1, a measuring device 100 for measuring the thickness of an electrode plate may include a sensor module 110, a communication module 120, a memory 130, and a processor 140. Each component included in the measuring device 100 may be connected to each other through a common bus or through a separate interface or a separate bus centered on the processor 140. In one or more other embodiments, in addition to Figure 1 the components shown, the measuring device 100 may further include various components, or the measuring device 100 may omit some of these components.

[0064] The sensor module 110 may be located upstream of a drying furnace adapted to dry the electrode plate 10 coated with an active material slurry. The sensor module 110 may detect the thickness of the electrode plate 10. The sensor module 110 may detect the thickness of the electrode plate 10 before the active material slurry coated on the electrode plate 10 is dried. The sensor module 110 may detect the electrode plate thickness at each position in the width direction of the electrode plate 10.

[0065] Referring to Figure 2A and Figure 2B , the electrode plate 10 may include a base layer (or current collector) 11 and an active material coating layer 12. The base layer 11 may be a metal sheet. For a cathode plate, the base layer 11 may be composed of aluminum or nickel, and for an anode plate, the base layer 11 may be composed of copper, nickel, or stainless steel. The composition of the base layer 11 is not limited thereto. For a cathode plate, the active material coating layer 12 may be composed of a cathode material, or for an anode plate, the active material coating layer 12 may be composed of an anode material.

[0066] The active material coating layer 12 may be formed on the electrode plate 10. The electrode plate 10 may be formed with multiple columns of the active material coating layer 12. The electrode plate 10 may be moved in the Y direction by a guide roller, and the sensor module 110 may periodically detect the electrode plate thickness at each position in the X direction of the electrode plate 10.

[0067] Referring to Figure 3 , the sensor module 110 may include a first sensor module 111 and a second sensor module 112. The first sensor module 111 may be located above the electrode plate 10. The first sensor module 111 may measure the distance from the first sensor module 111 to the electrode plate 10. Referring again to Figure 3 , the first sensor module 111 may include a first displacement sensor 111-1, a first movable module 111-2, and a first base 111-3.

[0068] The first base 111-3 can be located at a position separated by a distance (e.g., a predetermined distance) from a point on the moving path of the electrode plate 10 in the height direction (the positive direction of the Z-axis) of the electrode plate 10. The first movable module 111-2 can be movable on the first base 111-3. The first movable module 111-2 can be movable in the width direction (X-axis direction) of the electrode plate 10. The first movable module 111-2 can include a motor, a track, etc. The first displacement sensor 111-1 can be located below the first movable module 111-2. The first displacement sensor 111-1 can be a laser displacement sensor. The first displacement sensor 111-1 can detect the distance to the upper surface of the electrode plate 10.

[0069] If the first movable module 111-2 is located above a column of the active material coating layer 12, the first displacement sensor 111-1 can detect the distance to the upper surface of the active material coating layer 12 as the distance to the electrode plate 10. If the first movable module 111-2 is located in an area other than the area above the column of the active material coating layer 12, the first displacement sensor 111-1 can detect the distance to the upper surface of the base layer 11 as the distance to the electrode plate 10.

[0070] The second sensor module 112 can be located below the electrode plate 10. The second sensor module 112 can measure the distance from the second sensor module 112 to the electrode plate 10. The second sensor module 112 can include a second displacement sensor 112-1, a second movable module 112-2, and a second base 112-3.

[0071] The second base 112-3 can be located at a position separated by a distance (e.g., a predetermined distance) from a point on the moving path of the electrode plate 10 in the height direction (the negative direction of the Z-axis) of the electrode plate 10. The second movable module 112-2 can be movable on the second base 112-3. The second movable module 112-2 can be movable in the width direction (X-axis direction) of the electrode plate 10. The second movable module 112-2 can include a motor, a track, etc. The second displacement sensor 112-1 can be located on the second movable module 112-2. The second displacement sensor 112-1 can be a laser displacement sensor. The second displacement sensor 112-1 can detect the distance to the lower surface of the electrode plate 10.

[0072] The first movable module 111-2 and the second movable module 112-2 can operate independently. The first movable module 111-2 and the second movable module 112-2 can be synchronously controlled. The first movable module 111-2 and the second movable module 112-2 can be positioned to always face each other. For example, if the first movable module 111-2 is located at the point (a, b) on the X-Y axis, the second movable module 112-2 can also be located at the point (a, b) on the X-Y axis.

[0073] The first movable module 111-2 can generate heat during operation. The heat generated during the operation of the first movable module 111-2 can be transferred to the first base 111-3. If the heat generated during the operation of the first movable module 111-2 continues to be transferred to the first base 111-3, the first base 111-3 may suffer thermal deformation, as Figure 4 shown. The heat generated during the operation of the first movable module 111-2 may increase the length of the first base 111-3, causing the first base 111-3 to bend. The thermal deformation of the first base 111-3 may cause measurement errors in the first displacement sensor 111-1. For example, if the base layer 11 has a thickness of 8 μm, a temperature change of about 10 °C may cause a measurement error of about 0.4 μm. The second sensor module 112 may experience the same phenomenon.

[0074] The communication module 120 can communicate with an external device. For example, the communication module 120 can communicate with an active material coating device adapted to coat the electrode plate 10 with an active material, and can send information about the active material coating thickness calculated by the processor 140 as described below to the active material coating device.

[0075] The memory 130 can store at least one instruction executed by the processor 140. Such a memory 130 can be implemented by volatile and / or non-volatile storage media (e.g., read-only memory (ROM) and / or random access memory (RAM)). The memory 130 can store various information suitable for the operation of the processor 140. The memory 130 can store various information generated by the processor 140 during its operation.

[0076] The processor 140 can be operably connected to the sensor module 110, connected to the communication module 120, and connected to the memory 130. The processor 140 can be implemented by a central processing unit (CPU) or a system-on-chip (SoC). The processor 140 can run an operating system or an application to control multiple hardware or software components connected to the processor 140, and can perform various data processing and calculations. The processor 140 can be configured to execute at least one instruction stored in the memory 130 and store the execution result data in the memory 130.

[0077] The processor 140 can detect the thickness of the electrode plate at each position in the width direction through the sensor module 110, can calculate the thickness of the active material coating at each position based on the thickness of the electrode plate at each position, can calculate the measurement error caused by the thermal deformation of the sensor module 110, and can compensate the calculated thickness of the active material coating at each position based on the calculated measurement error. The processor 140 can calculate the measurement error caused by the thermal deformation of the first base 111-3 and the second base 112-3, and can compensate the calculated thickness of the active material coating at each position based on the calculated measurement error at each position to achieve a more accurate calculation of the thickness of the active material coating.

[0078] In the following description, based on the above description, an apparatus and a method for measuring the thickness of an electrode plate according to one or more embodiments of the present disclosure will be described. Some of the processes described below may be executed in an order different from the order described herein or may be omitted.

[0079] Figure 5 is a flowchart showing a method for measuring the thickness of an electrode plate, Figure 6A and Figure 6B is a view showing a process of calculating the thickness of the active material coating.

[0080] Referring to Figure 5 , the processor 140 can first detect the thickness of the electrode plate at each position through the sensor module 110 (S501). As Figure 6B shown, the processor 140 can repeatedly execute the process of detecting the thickness of the electrode plate through the sensor module 110 while moving the sensor module 110 in the X-axis direction. The processor 140 can detect the thickness of the electrode plate based on the distance to the upper surface of the electrode plate 10 detected by the first sensor module 111 and based on the distance to the lower surface of the electrode plate 10 detected by the second sensor module 112.

[0081] Next, the processor 140 can calculate the thickness of the active material coating at each position based on the detected thickness of the electrode plate at each position (S503). The processor 140 can calculate the thickness of the active material coating at each position by performing a process of subtracting the thickness of the electrode plate measured before coating the active material from the thickness of the electrode plate detected at each position of the electrode plate. The processor 140 can subtract from Figure 6A the thickness of the electrode plate detected in the state shown in Figure 6BThe thickness of the electrode plate detected in the state shown is used to calculate the active material coating thickness. The thickness of the electrode plate at each position before coating the active material can be pre-detected and stored in the memory 130. Here, the thickness of the electrode plate measured before coating the active material may refer to the thickness of the electrode plate measured before thermal deformation occurs in the sensor module 110. For example, it does not include the measurement error of the electrode plate caused by the thermal deformation of the sensor module 110.

[0082] Next, the processor 140 may calculate the measurement error at each position due to the thermal deformation of the sensor module 110 (S505), and may compensate the calculated active material coating thickness at each position based on the calculated measurement error at each position (S507). The processor 140 may compensate the active material coating thickness at each position by performing a process of subtracting the measurement error calculated in S505 from the active material coating thickness calculated in S503 for each position of the electrode plate.

[0083] If the sensor module 110 operates continuously, the heat generated from the sensor module 110 may cause thermal deformation of the sensor module 110. In one or more embodiments, the active material coating thickness calculated in S503 may include a measurement error caused by the thermal deformation of the sensor module 110. By compensating for the measurement error caused by the thermal deformation of the sensor module 110, the active material coating thickness can be calculated more accurately.

[0084] Figure 7 is a flowchart showing the process of calculating the measurement error caused by the thermal deformation of the sensor module, Figure 8 is a view of the process of calculating the measurement error caused by the thermal deformation of the sensor module.

[0085] Referring to Figure 7 , the processor 140 may first detect the thickness of the electrode plate at a position where no active material is coated (hereinafter referred to as the first position) (S701). Since the electrode plate 10 is formed with columns of the active material coating layer 12, the region (positioning region) of the electrode plate 10 in the width direction (X-axis direction) may be divided into a region where the active material coating layer 12 is formed and a region where the active material coating layer 12 is not formed.

[0086] The region of the electrode plate where the active material coating layer 12 is not formed will be defined as the first region, and the position in the first region will be defined as the first position. In addition, the region of the electrode plate where the active material coating layer 12 is formed may be defined as the second region, and the position in the second region will be defined as the second position.

[0087] For example, assume that as Figure 8As shown, six columns of active material coating layers 12 are formed on the electrode plate 10. Then, there can be seven first regions and six second regions on the electrode plate 10, and the processor 140 can perform the process of detecting the thickness of the electrode plate in each of the seven first regions.

[0088] Next, the processor 140 can perform the process of subtracting the thickness of the electrode plate measured at the first position before coating the active material from the thickness of the electrode plate at the first position for each first position (S703). The processor 140 can calculate the measurement error at each first position by performing the process of subtracting the thickness of the electrode plate measured at the first position (actual thickness) before coating the active material from the thickness of the electrode plate at the first position detected via the sensor module 110 for each first position. The thickness of the electrode plate at each position before coating the active material can be pre-detected and stored in the memory 130. Here, the thickness of the electrode plate before coating the active material can refer to the thickness of the electrode plate measured before thermal deformation occurs in the sensor module 110, for example, the thickness of the electrode plate excluding the measurement error caused by the thermal deformation of the sensor module 110.

[0089] For example, as Figure 8 shown, the processor 140 can repeatedly perform the process of subtracting D M (regarding the thickness of the electrode plate at the first position detected by the sensor module 110) from D R (the thickness of the electrode plate before coating the active material) for each point located in the first region to calculate the measurement error E M at the first position.

[0090] Next, the processor 140 can perform interpolation based on the measurement error at the first position to calculate the measurement error at the second position coated with the active material (S705). Since the active material coating layer 12 is formed in the second region, the measurement error at the second position cannot be calculated by the same process as the process of calculating the measurement error at the first position. In one or more embodiments, an interpolation method is applied to the measurement error at the first position to calculate the measurement error at the second position. The processor 140 can use various interpolation methods including linear interpolation, polynomial interpolation, spline interpolation, Lagrange interpolation, etc. to perform interpolation.

[0091] Figure 9 is a flowchart showing the process of determining the occurrence of coating failure, Figure 10 、 Figure 11 and Figure 12 are views showing the process of determining the occurrence of coating failure.

[0092] Referring to Figure 9, the processor 140 may first determine one of the multiple columns of active material coating layers 12 formed on the electrode plate 10 as the target column (S901). The processor 140 may determine a column among the multiple columns of active material coating layers 12 that has never been determined as the target column as the target column. Figure 10 shows the electrode plate thicknesses at multiple positions of the entire electrode plate 10, Figure 11 shows the electrode plate thicknesses at multiple positions in one column of the active material coating layer 12.

[0093] Next, the processor 140 may calculate the average value of the active material coating thicknesses at multiple positions in the target column (hereinafter referred to as the first average value) (S903). The processor 140 may calculate the first average value after removing the edge region of the target column.

[0094] Next, the processor 140 may determine whether there is a position in the target column where the active material coating thickness is less than or equal to a first threshold value set based on the first average value (S905). The processor 140 may set the first threshold value to be equal to the value obtained by multiplying the first average value by a preset first ratio. For example, the first ratio may be about 0.9%, but is not limited thereto.

[0095] Next, the processor 140 may determine whether a coating failure has occurred in the target column based on the determination result regarding whether there is a position in the target column where the active material coating thickness is less than or equal to the first threshold value (S907). When it is determined that there is a position in the target column where the active material coating thickness D C is less than or equal to the first threshold value D A1 , the processor 140 may determine that a coating failure has occurred in the target column. When it is determined that a coating failure has occurred in the target column, the processor 140 may output a warning signal. In one or more embodiments, as Figure 12 shown, when it is determined that there is no position in the target column where the active material coating thickness D C is less than or equal to the first threshold value D A1 , the processor 140 may determine that the target column has a normal coating state.

[0096] If the active material slurry cannot be normally discharged from the slit die due to being obstructed by foreign objects or the like, the active material coating layer 12 may have stripe defects. At the position where the stripe defects occur, the thickness of the electrode plate 10 is detected as a smaller value than at other positions. This fact can be used to determine the occurrence of a coating failure on the electrode plate 10.

[0097] Next, the processor 140 may determine whether the process of determining the occurrence of a coating failure has been completed for all columns of the active material coating layers 12 formed on the electrode plate 10 (S909).

[0098] When it is determined that the process of determining the occurrence of coating failure has not been completed for all columns of the active material coating layer 12 formed on the electrode plate 10, the processor 140 may execute S901 again. In one or more embodiments, when it is determined that the process of determining the occurrence of coating failure has been completed for all columns of the active material coating layer 12 formed on the electrode plate 10, the processor 140 may terminate the corresponding process.

[0099] Figure 13 is a flowchart showing the process of determining the occurrence of coating failure, Figure 14 is a view showing the process of determining the occurrence of coating failure.

[0100] When it is determined that there is no position in the target column where the coating thickness of the active material is less than or equal to the first threshold, the process shown in Figure 13 can be executed to secondarily verify the occurrence of coating failure on the target column.

[0101] Referring to Figure 13 , the processor 140 may first divide the target column into a plurality of zones (S1301). The processor 140 may divide the target column into a preset number of zones. Each zone may have the same length.

[0102] Next, the processor 140 may determine one of the plurality of zones as the target zone (S1303). The processor 140 may determine as the target zone one that has never been determined as the target zone among the zones.

[0103] Next, the processor 140 may calculate the average value of the coating thicknesses of the active material at a plurality of positions in the target zone (hereinafter referred to as the second average value) (S1305).

[0104] Next, the processor 140 may determine whether there is a position in the target zone where the coating thickness of the active material is less than or equal to a second threshold set based on the second average value (S1307). The processor 140 may set the second threshold to a value equal to the second average value multiplied by a preset second ratio. For example, the second ratio may be set between about 0.7 and about 0.99, but is not limited thereto.

[0105] Next, the processor 140 may determine whether coating failure has occurred in the target zone based on the determination result regarding whether there is a position in the target zone where the coating thickness of the active material is less than or equal to the second threshold. (S1309). As shown in Figure 14 , when it is determined that there is a coating thickness D of the active material in the target zone C less than or equal to the second threshold D A2When at the position of, the processor 140 may determine that a coating failure has occurred in the target area. When it is determined that a coating failure has occurred in the target area, the processor 140 may output a warning signal. In one or more embodiments, when it is determined that there is no coating thickness D of the active material in the target area C less than or equal to the second threshold D A2 at the position of, the processor 140 may determine that the target area has a normal coating state.

[0106] Next, the processor 140 may determine whether the process of determining the occurrence of a coating failure has been completed for all areas on the electrode plate 10 (S1311).

[0107] When it is determined that the process of determining the occurrence of a coating failure has not been completed for all areas on the electrode plate 10, the processor 140 may execute S1301 again. In one or more embodiments, when it is determined that the process of determining the occurrence of a coating failure has been completed for all areas, the processor 140 may terminate the corresponding process.

[0108] Figure 15 is a diagram of an electrode plate coating device according to one or more embodiments of the present disclosure.

[0109] Referring to Figure 15 , the electrode plate coating device 30 may include a storage tank 31, a pump 32, a valve 33, a slit die 34, a guide roller 35, and a control module in one or more embodiments.

[0110] The storage tank 31 may store the active material slurry. The pump 32 may be connected to the storage tank 31. The pump 32 may supply the active material slurry stored in the storage tank 31 to the slit die 34. The slit die 34 may discharge the active material slurry through a discharge port to coat the electrode plate 10 with the active material slurry. The valve 33 may be formed between the slit die 34 and the pump 32 to adjust the amount of the active material slurry supplied to the slit die 34. The guide roller 35 may move the electrode plate 10.

[0111] The control module may control the pump 32, the valve 33, and the slit die 34. The control module may control the revolutions per minute (RPM) of the pump 32. The control module may perform feedback control on the revolutions per minute of the pump 32 based on the coating thickness of the active material (compensated coating thickness of the active material) detected by the measuring device 40 for measuring the electrode plate thickness. If the coating thickness of the active material exceeds a preset thickness, the control module may decrease the revolutions per minute of the pump 32, and if the coating thickness of the active material is less than or equal to the preset thickness, the control module may increase the revolutions per minute of the pump 32.

[0112] The control module can control the opening degree of valve 33. The control module can perform feedback control on the opening degree of valve 33 based on the thickness of the active material coating (compensated thickness of the active material coating) detected by the measuring device 40. If the thickness of the active material coating exceeds the preset thickness, the control module can reduce the opening degree of valve 33, and if the thickness of the active material coating is less than the preset thickness, the control module can increase the opening degree of valve 33.

[0113] The control module can control the gap of the slot die 34. The control module can perform feedback control on the gap of the slot die 34 based on the thickness of the active material coating (compensated thickness of the active material coating) detected by the measuring device 40. If the thickness of the active material coating exceeds the preset thickness, the control module can reduce the gap of the slot die 34, and if the thickness of the active material coating is less than the preset thickness, the control module can increase the gap of the slot die 34.

[0114] The control module can control the pump 32 to control the thickness of the active material coating over the entire area of the electrode plate 10, or can control the valve 33 and the slot die 34 to control the thickness of the active material coating for one column of the active material coating layers 12.

[0115] The electrode plate 10 coated with the active material slurry can be moved to the drying furnace 50 by the measuring device 40. The measuring device 40 can detect the thickness of the active material coating at each position in the width direction and can send the detected value to the control module. The drying furnace 50 can dry the electrode plate 10 coated with the active material slurry.

[0116] According to the present disclosure, the thickness of the active material coating layer formed on the electrode plate can be measured before drying the electrode plate by the dryer.

[0117] According to the present disclosure, by compensating for the measurement error caused by the thermal deformation of the sensor module, the thickness of the active material coating layer formed on the electrode plate can be calculated more accurately.

[0118] According to the present disclosure, stripe defects occurring during the process of coating the electrode plate with the active material slurry can be detected.

[0119] Although the present disclosure has been described with reference to some embodiments and the drawings showing aspects thereof, the present disclosure is not limited thereto. Those skilled in the art to which the present disclosure pertains can make various modifications and variations within the scope of the present disclosure, the claims, and their functional equivalents.

[0120] This application claims the priority and benefits of Korean Patent Application No. 10-2023-0194966, filed with the Korean Intellectual Property Office on December 28, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. A device for measuring the thickness of an electrode plate, the device comprising: a sensor module configured to detect the thickness of the electrode plate upstream of the drying oven; as well as A processor is connected to the sensor module and is configured to: Detecting the thickness of the electrode plate in the width direction by the sensor module; calculating an active material coating thickness based on the thickness of the electrode plate; and The active material coating thickness is compensated based on a measurement error caused by thermal deformation of the sensor module.

2. The device according to claim 1, wherein the sensor module comprises: A first sensor module, configured to measure the distance to the electrode plate above the electrode plate; and a second sensor module configured to measure the distance to the electrode plate below the electrode plate, wherein the first sensor module and the second sensor module are configured to be synchronously controlled. 3 . The apparatus according to claim 1 , wherein the processor is configured to calculate the active material coating thickness by subtracting an electrode plate thickness measured before coating an active material from the thickness of the electrode plate detected by the sensor module. 4 . The apparatus of claim 1 , wherein the processor is configured to detect a thickness of an electrode plate at a first position where an active material is not coated, and calculate the measurement error based on the thickness of the electrode plate at the first position.

5. The apparatus of claim 4, wherein the processor is configured to calculate the measurement error at the first location by subtracting the electrode plate thickness measured at the first location before applying the active material from the electrode plate thickness at the first location. 6 . The apparatus of claim 5 , wherein the processor is configured to perform interpolation based on the measurement error at the first location to calculate the measurement error at a second location coated with the active material. 7 . The apparatus of claim 1 , wherein the processor is configured to compensate the active material coating thickness by subtracting the measurement error from the active material coating thickness.

8. The apparatus according to claim 1, wherein the processor is configured to send information about the active material coating thickness to an active material coating device configured to coat the electrode plate with an active material, so that a pump, a valve and a slit die of the active material coating device are feedback controlled. 9 . The apparatus of claim 1 , wherein the processor is configured to determine whether a coating failure of the electrode plate occurs based on the active material coating thickness.

10. An apparatus according to claim 9, wherein the processor is configured to determine a target column among columns of active material coating layers on the electrode plate, and is configured to determine whether the coating failure occurs in the target column by repeating a process of determining whether the coating failure occurs in the target column while changing the target column.

11. The apparatus according to claim 10, wherein the processor is configured to calculate a first average value of active material coating thickness for the target column, and determine that the coating failure occurs in the target column based on a position in the target column where the active material coating thickness is less than or equal to a first threshold value set based on the first average value.

12. The device according to claim 10, wherein the processor is configured to determine whether the coating failure occurs in the target column by dividing the target column into a plurality of zones, determining a target zone among the plurality of zones, and repeating a process of determining whether the coating failure occurs in the target zone while changing the target zone.

13. The apparatus according to claim 12, wherein the processor is configured to calculate a second average value of the active material coating thickness for the target area, and determine that the coating failure occurs in the target area based on a position in the target area where the active material coating thickness is less than or equal to a second threshold value set based on the second average value.

14. A method for measuring the thickness of an electrode plate, the method comprising: upstream of the drying furnace, detecting the electrode plate thickness of the electrode plate in the width direction by a sensor module; Calculating the active material coating thickness based on the electrode plate thickness; as well as The active material coating thickness is compensated based on a measurement error caused by thermal deformation of the sensor module. 15 . The method of claim 14 , wherein calculating the active material coating thickness comprises subtracting an electrode plate thickness measured before coating the active material from the electrode plate thickness detected by the sensor module. 16 . The method of claim 14 , wherein calculating the measurement error comprises detecting a thickness of an electrode plate at a first position where an active material is not coated and calculating the measurement error based on the thickness of the electrode plate at the first position. 17 . The method of claim 16 , wherein calculating the measurement error comprises subtracting an electrode plate thickness measured at the first position before coating the active material from the electrode plate thickness at the first position to calculate the measurement error at the first position. 18 . The method of claim 17 , wherein calculating the measurement error comprises performing interpolation based on the measurement error at the first position to calculate the measurement error at a second position coated with the active material.

19. The method of claim 14, wherein compensating the active material coating thickness comprises subtracting the measurement error from the active material coating thickness to compensate for the active material coating thickness.

20. The method of claim 14, further comprising sending information about the active material coating thickness to an active material coating device configured to coat the electrode plate with an active material so that a pump, a valve and a slit die of the active material coating device are feedback controlled.

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