Method for managing the sliding area of ​​an electrode

Abstract

The present technology relates to a method for managing a sliding area of ​​an electrode, the method comprising: (a) a process of determining a specific area where a positive electrode and a negative electrode, which are management objects to be used when manufacturing an electrode assembly, face each other and setting a measurement position in the specific area; (b) a process of measuring the thickness and filling amount of each electrode mixture layer of the positive electrode and the negative electrode at the set measurement position; (c) a process of measuring the thickness and filling amount of the electrode mixture layer at each central part of the positive electrode and the negative electrode; and (d) a process of calculating the ratio of the thickness of the electrode mixture layer of the positive electrode and the negative electrode measured in process (b) to the thickness of the central part measured in process (c).

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0142659, filed on October 30, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for managing a sliding area of ​​an electrode, and more particularly, to a method for managing a sliding area of ​​an electrode by preventing an NP ratio inversion phenomenon by managing a loading amount and a thickness of an electrode mixture layer according to a local position where a positive electrode and a negative electrode face each other. Background Art

[0003] As the technology of mobile devices, automobiles, and energy storage devices develops and their demand increases, the demand for batteries as energy sources is also growing rapidly. Therefore, many studies have been conducted on lithium secondary batteries with high energy density and discharge voltage, and such lithium secondary batteries have been widely used.

[0004] Secondary batteries are classified into cylindrical batteries and prismatic batteries in which an electrode assembly is embedded in a cylindrical or prismatic metal according to the shape of a battery case, and pouch batteries in which an electrode assembly is embedded in a pouch-shaped case of an aluminum laminate.

[0005] In addition, the electrode assembly embedded in the battery case is a power generation element capable of charging / discharging, which is composed of a stacked structure of positive electrode / separator / negative electrode. Representative examples thereof include a jelly roll electrode assembly in which a long sheet type positive electrode and negative electrode are wound with a separator inserted between them; a stacked electrode assembly in which a plurality of positive electrodes and negative electrodes cut in units of a predetermined size are stacked in sequence with a separator inserted therebetween; and a stacked / foldable electrode assembly in which a bi-cell or a full cell is wound, in which a predetermined unit of positive electrode and negative electrode are stacked with a separator inserted therebetween.

[0006] The positive electrode and negative electrode constituting the electrode assembly are manufactured in the following manner: the electrode slurry prepared in the mixing process is coated on the electrode current collector in a predetermined pattern and constant thickness by a slot die, and then the electrode slurry is dried. However, since the electrode slurry is a fluid, it flows downward after being coated, and this downward flow of the electrode slurry is called sliding. This sliding may occur frequently at both ends in the width direction of the coating portion where the electrode active material has been coated. Similarly, the portion where the thickness of the slurry coating gradually changes to form the inclined portion is called the sliding area.

[0007] The sliding area is shown in the range of 30mm or 20mm from the boundary line of the uncoated part toward the coated part. Figure 1As shown, the length of the sliding area of ​​the negative electrode may be different from the length of the sliding area of ​​the positive electrode, and the shape of the sliding area may be a straight line or a curve. In addition, the slopes of the sliding areas of the positive and negative electrodes may be different. Therefore, depending on the position where the positive and negative electrodes face each other, there may be a portion where the NP ratio is unbalanced, and the imbalance of the NP ratio may lead to safety accidents, such as short circuits caused by lithium precipitation in the negative electrode. Therefore, a method for managing the NP ratio in the sliding area of ​​the electrode is needed, but there is no standardized method for determining or measuring electrode sliding. Therefore, this technology is needed. Summary of the invention

[0008] Technical issues

[0009] The present invention is believed to solve at least some of the above problems.For example, one aspect of the present invention provides a method of managing a sliding region of an electrode for preventing NP-ratio reversal in the sliding region of the electrode.

[0010] Technical Solution

[0011] A method for managing the sliding area of ​​an electrode for solving a problem, comprising: process (a), determining a specific area where a positive electrode and a negative electrode, which are management objects to be used when manufacturing an electrode assembly, face each other, and setting a measurement position in the specific area; process (b), measuring the thickness and filling amount of each electrode mixture layer of the positive electrode and the negative electrode at the set measurement position; process (c), measuring the thickness and filling amount of the electrode mixture layer at each central part of the positive electrode and the negative electrode; and process (d), calculating the ratio of the thickness of the electrode mixture layer of the positive electrode and the negative electrode measured in process (b) to the thickness of the central part measured in process (c).

[0012] The method of managing the sliding area of ​​the electrode further includes a process (e) of calculating a ratio (NP ratio) of the capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode at the measurement position.

[0013] In one embodiment of the present invention, process (e) includes: process (e-1) accumulates the correlation data of each filling amount of the positive electrode and the negative electrode, the ratio of each thickness of the positive electrode and the negative electrode, and the NP ratio by repeating processes (a)-(d) while changing the measurement positions of the positive and negative electrodes of the sample; process (e-2) derives a correlation equation by analyzing the accumulated data; and process (e-3) calculates the NP ratio by substituting the filling amount measured in process (b) and the ratio of the thickness calculated in process (d) into the correlation equation of the positive and negative electrodes as the management objects.

[0014] In one embodiment of the present invention, the process (a) includes setting a plurality of measurement positions (X1, X2) at regular intervals along the width direction (x axis) on the center line in the longitudinal direction of the electrode. 2... X n At this time, the method may further include further measuring the position (X1, X 2... X n ) at each point in the longitudinal direction (y-axis) of the electrode at regular intervals.

[0015] In another embodiment of the present invention, process (a) includes: (a-1) process of making an image of a plurality of vertical lines at regular intervals along the width direction (x-axis) of the electrode at a specific area; (a-2) process of making an image of a plurality of horizontal lines at regular intervals along the longitudinal direction (y-axis) in the set sliding area; (a-3) process of setting a plurality of rectangular areas formed by the intersection of vertical lines and horizontal lines as segmentation areas; and (a-4) process of setting a corresponding arbitrary point in the set segmentation area as a measurement position. At this time, each interval of the plurality of vertical lines of process (a-1) and each interval of the plurality of horizontal lines of process (a-2) are within the range of 0.05 to 0.2 mm.

[0016] In one embodiment of the present invention, process (b) and process (c) may include measuring the thickness of the electrode mixture layer using a rotating caliper.

[0017] In one embodiment of the present invention, process (b) may include measuring the loading amount of the electrode mixture layer using a mesh gauge.

[0018] In one embodiment of the present invention, the positive electrode and the negative electrode of process (b) are electrodes obtained by coating an electrode slurry containing an electrode active material on a current collector and then drying the electrode slurry.

[0019] In one embodiment of the present invention, the positive electrode and the negative electrode of process (b) are electrodes before undergoing a rolling process.

[0020] Beneficial Effects

[0021] The present invention provides a method for easily managing the NP ratio by measuring the thickness and loading amount of the electrode mixture layer in the positive electrode and the negative electrode including the sliding area of ​​the electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a graph showing the difference between the length of the sliding region of the positive electrode and the length of the sliding region of the negative electrode.

[0023] Figure 2 is a flow chart of a method for managing a sliding area of ​​an electrode according to one embodiment of the present invention.

[0024] Figure 3 is a flow chart of a method for managing a sliding area of ​​an electrode according to another embodiment of the present invention.

[0025] Figure 4 are a plan view and a cross-sectional view showing a sliding area of ​​an electrode.

[0026] Figure 5 is a schematic diagram showing a part of a process of measuring the thickness of an electrode mixture layer.

[0027] Figures 6 to 8 is a schematic diagram illustrating a process of setting a measurement location according to various embodiments of the present invention. DETAILED DESCRIPTION

[0028] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The terms and words used in this specification and claims should not be interpreted as limited to common terms or dictionary terms, and the inventors can appropriately define the concepts of the terms in order to best describe their inventions. The terms and words should be interpreted as meanings and concepts consistent with the technical concept of the present invention.

[0029] In the present application, it should be understood that terms such as "including" or "having" are intended to indicate that the described features, quantities, steps, operations, components, parts or combinations thereof are present in the present application, and they do not preclude the possibility of the presence or addition of one or more other features or quantities, steps, operations, components, parts or combinations thereof. In addition, when a part such as a layer, a film, a region, a plate, etc. is referred to as being "on" another part, this includes not only the case where the part is "directly" "on" the other part, but also the case where other parts are inserted between the part and the other part. On the other hand, when a part such as a layer, a film, a region, a plate, etc. is referred to as being "under" another part, this includes not only the case where the part is "directly" "under" the other part, but also the case where other parts are inserted between the part and the other part. In addition, to be set "on" in the present application may include the case where it is set at the bottom as well as the top.

[0030] In the present invention, the NP ratio is defined as a value obtained by dividing the total capacity of the negative electrode by the total capacity of the positive electrode.

[0031] In the present invention, the sliding area refers to an area where the thickness of the electrode mixture layer gradually decreases toward the uncoated part in the area near the boundary between the uncoated part and the coated part, on which the electrode mixture layer (positive electrode mixture layer and negative electrode mixture layer) is not coated, and on which the electrode mixture layer is coated. That is, the sliding area should be understood as a portion where the flatness of the electrode mixture layer is reduced in the area near the boundary between the coated part and the uncoated part and its adjacent portion.

[0032] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0033] Generally, the NP ratio of the electrode has been managed by the thickness and the filling amount of the central part of the electrode. This management method can be used in a flat portion where the thickness of each of the positive electrode mixture layer and the negative electrode mixture layer is constant. However, in the case where the length of each sliding area of ​​the positive electrode and the negative electrode where sliding has occurred is different, and the reduction rate of the thickness of the positive electrode mixture layer in each sliding area of ​​the positive electrode and the negative electrode is different from the reduction rate of the thickness of the negative electrode mixture layer in each sliding area of ​​the positive electrode and the negative electrode, it is difficult to determine whether the NP ratio reversal has occurred by using the conventional management method.

[0034] Figure 1 is a diagram showing the difference between the length of the sliding region of the positive electrode and the length of the sliding region of the negative electrode. Figure 1 , the positive electrode mixture layer 12 of the positive electrode 10 faces the negative electrode mixture layer 22 of the negative electrode 20, and the positive electrode mixture layer 12 and the negative electrode mixture layer 22 each have a sliding region (S or S') in which the thickness gradually decreases in a direction extending toward the uncoated portion at the end. As described above, since the electrode slurry is a fluid, such a sliding region is frequently generated in the boundary region between the coated portion and the uncoated portion due to the flow characteristics of the electrode slurry.

[0035] Generally, when the NP ratio is equal to or greater than 1, lithium is not deposited during charge / discharge, and in particular, the battery does not deteriorate rapidly during high-speed charge / discharge. Therefore, when designing an electrode assembly, the electrode assembly is designed to allow the NP ratio to be equal to or greater than 1. In the case where the positive electrode and the negative electrode include a sliding region, a reversal phenomenon of the NP ratio may occur, in which the NP ratio locally becomes less than 1, depending on the length of the sliding region, the shape (curve or straight line) of the sliding region, or the slope.

[0036] In order to calculate the NP ratio in the sliding area, an accurate method is to calculate the NP ratio for the positive electrode and the negative electrode that are the management objects, at the position where the positive electrode faces the negative electrode, taking into account the filling amount, thickness, capacity of the active material, and tolerance, etc. However, in large-scale production, it is not easy to calculate the NP ratio of all products in the sliding area.

[0037] Therefore, the present invention provides a novel method for managing the NP ratio by measuring the thickness of the positive electrode mixture layer and the thickness of the negative electrode mixture layer in the sliding area when at least one of the positive electrode and the negative electrode includes at least one sliding area in the area where the positive electrode faces the negative electrode.

[0038] Figure 2is a flow chart of a method for managing a sliding area of ​​an electrode according to an embodiment of the present invention. Figure 2 The method for managing the sliding area of ​​an electrode of the present invention includes: (a) a process of determining a specific area in which a positive electrode and a negative electrode, which are management objects to be used when manufacturing an electrode assembly, face each other, and setting a measurement position in the specific area; (b) a process of measuring the thickness and filling amount of each electrode mixture layer of the positive electrode and the negative electrode at the set measurement position; (c) a process of measuring the thickness and filling amount of the electrode mixture layer at each central part of the positive electrode and the negative electrode; and (d) a process of calculating the ratio of the thickness of the electrode mixture layer of the positive electrode and the negative electrode measured in process (b) to the thickness of the central part measured in process (c).

[0039] First, process (a) will be described. Process (a) is a process of determining an area in which the positive electrode and the negative electrode as the management object face each other and setting a measurement position in the determined area for measuring the thickness and filling amount of each of the positive electrode mixture layer and the negative electrode mixture layer when assembling an electrode assembly having the positive electrode and the negative electrode.

[0040] Since the object of the present invention is to locally prevent the inversion of the NP ratio in the sliding region, the process (a) is to set the measurement position in a position where the positive electrode and the negative electrode face each other in the sliding region.

[0041] Figures 6 to 8 Shown are measurement locations arranged according to various embodiments of the present invention.

[0042] First, refer to Figure 6 The process (a) may include setting a plurality of measurement positions (X1, X2) at regular intervals along the width direction (x axis) on the center line in the longitudinal direction of the electrode in the region where the positive electrode faces the negative electrode. 2... X n ). In addition, the process (b) described later is performed at the set measurement position.

[0043] At this time, the separation distance between the plurality of measurement positions may be in the range of 0.05 to 2 mm, preferably in the range of 0.07 to 1 mm, and more preferably in the range of 0.1 to 0.5 mm.

[0044] Some of the measurement positions are located at the sliding area, and other measurement positions may be located at an area other than the sliding area.

[0045] The sliding area is an area where the thickness of the electrode mixture layer decreases toward the uncoated portion and increases toward the coated portion, and the thickness of the electrode mixture layer changes continuously according to the measurement position in the sliding area. Therefore, it is preferable that the interval between the measurement positions set by the process (a) is relatively small in the sliding area for more accurate management. In addition, as Figure 4 As shown, in the portion A other than the sliding area (S and S'), even if the measurement position changes, the thickness of the electrode mixture layer can be constant in the measurement position. Therefore, it is not a problem that the interval between the measurement positions in the area (A) other than the sliding area (S and S') of the electrode mixture layer is relatively large. For quick and efficient management, it is preferred that the interval between the measurement positions in the area other than the sliding area is larger than the interval between the measurement positions in the sliding area.

[0046] According to another embodiment of the present invention, the method may further include further measuring the position (X1, X2) 2... X n ) at each point along the longitudinal direction (y-axis) of the electrode at regular intervals. Figure 7 , P1(X1, Y1), P2(X2, Y2), P3(X3, Y3), P4(X4, Y4)... can be set, which are measurement positions at regular intervals in the y-axis direction based on X1 among the measurement positions set as described above. Figure 7 Only four points, P1 (X1, Y1), P2 (X2, Y2), P3 (X3, Y3) and P4 (X4, Y4), are shown, but the present invention is not limited to these examples, and measurement positions may be further added or reduced.

[0047] In another embodiment of the present invention, process (a) includes: process (a-1), making an image of multiple vertical lines at regular intervals along the width direction (x-axis) of the electrode in a specific area; process (a-2), in a set sliding area, making an image of virtual horizontal lines extending in the width direction at regular intervals along the longitudinal direction (y-axis); process (a-3) setting multiple rectangular areas formed by the intersection of vertical lines and horizontal lines as segmentation areas; and process (a-4) setting each arbitrary point within the set segmentation area as a measurement position.

[0048] refer to Figure 8 , the area where the positive electrode and the negative electrode face each other can be divided into a plurality of sub-areas, as a plurality of horizontal lines parallel to the electrode width direction and a plurality of vertical lines parallel to the length direction intersecting each other in the area. In addition, any point P in any segmented area among the plurality of segmented areas can be set as a measurement position.

[0049] At this time, the separation distance between the vertical lines and the separation distance between the horizontal lines may be in the range of 0.05 to 2 mm, preferably in the range of 0.07 to 1 mm, and more preferably in the range of 0.1 to 0.5 mm.

[0050] Similarly, multiple points where the positive electrode faces the negative electrode can be set as measurement positions, but if there are too many measurement positions, a lot of effort and cost are required. Therefore, in process (a), the center point of the positive electrode sliding area and the point of the negative electrode mixture layer facing the center point, and the center point of the negative electrode sliding area and the point of the positive electrode mixture layer facing the center point can be set as measurement positions. Here, the center of the sliding area refers to the point corresponding to 1 / 2 in the x-axis direction in the sliding area.

[0051] Specifically, point 1 corresponding to 1 / 2 of the positive electrode sliding area and a point of the negative electrode mixture layer facing point 1 are set as measurement positions, and point 2 corresponding to 1 / 2 of the negative electrode sliding area and a point of the positive electrode mixture layer facing point 2 are set as measurement positions.

[0052] The process (b) will be described below. The process (b) of the present invention is a process for measuring the thickness and filling amount of each electrode mixture layer of the positive electrode and the negative electrode, which are the main elements for managing the electrode NP ratio. The process (b) of the present invention includes measuring the thickness of the positive electrode mixture layer of the positive electrode and the filling amount of the positive electrode, and the thickness of the negative electrode mixture layer of the negative electrode and the filling amount of the negative electrode in the measurement position set in the process (a).

[0053] In addition, the positive electrode as the measurement object is an electrode obtained by coating a positive electrode slurry containing a positive electrode active material on a positive electrode current collector and then drying the slurry, and the negative electrode is an electrode obtained by coating a negative electrode slurry containing a negative electrode active material on a negative electrode current collector and then drying the slurry. Since the electrode active material layer is in a fluid state after the electrode slurry is coated on the current collector, it is difficult to measure the thickness using a thickness measuring instrument. Therefore, the thickness is measured after the electrode active material layer is dried to a certain extent.

[0054] In addition, the positive electrode and the negative electrode may be electrodes before or after the rolling process. However, if the thickness of the electrode mixture layer is measured for an electrode that has undergone a rolling process, the electrode mixture layer including the sliding area is pressed as a whole during the rolling process, so the thickness deviation on the sliding area may not be large. Therefore, it may be preferable to use a thickness measuring instrument that can measure the thickness in micrometer units.

[0055] In an embodiment of the present invention, process (b) may include measuring the thickness of the electrode mixture layer using a rotating caliper. Figure 5 , in such Figure 5After the positive electrode or / and negative electrode as the management object is cut, the cut piece can be put into a rotary caliper and then the thickness of the electrode mixture layer at the set measurement position and the thickness of the electrode mixture layer at the center portion described later can be measured.

[0056] Furthermore, in an embodiment of the present invention, the process (b) may include measuring a filling amount of the electrode mixture layer by using a mesh gauge.

[0057] Furthermore, in an embodiment of the present invention, the process (b) may include calculating a loading amount of the electrode mixture layer by using an electrode loading design value.

[0058] The process (c) will be described below. The process (c) is a process of measuring the thickness of the electrode mixture layer at each central portion of the positive electrode and the negative electrode as the management object. This is a process required for calculating the thickness ratio of the process (d). At this time, the thickness of the electrode mixture layer can be measured by using a rotating caliper as in the process (b).

[0059] Here, each central portion of the positive electrode and the negative electrode refers to a portion that is not a sliding area and the thickness of the electrode mixture layer is constant. When the electrode slurry is applied, due to the fluid properties of the slurry, the sliding area is displayed at both ends in the width direction, and the thickness of the coating portion other than the sliding area is constant. Therefore, since the thickness of the electrode mixture layer at the center in the electrode width direction is the same as the thickness of the electrode of the coating portion located close to the sliding area, the process of measuring the electrode thickness at each central portion of the positive electrode and the negative electrode can be a process of measuring the thickness of the electrode mixture layer of the coating portion close to the sliding area but not the sliding area.

[0060] Here, the thickness of the electrode mixture layer in the center portion refers to the thickness of the electrode mixture layer at a position that does not belong to the sliding area, and specifically, it may be the thickness at a point that is 5 to 15 mm, 15 to 20 mm, 10 to 30 mm, or 20 to 30 mm away from the boundary between the uncoated portion and the coated portion.

[0061] This is because the sliding area of ​​the electrode can have a length of 5 to 15 mm, 15 to 20 mm, 10 to 30 mm, or 20 to 30 mm from the boundary between the coated portion and the uncoated portion toward the coated portion, and the thickness of the electrode mixture layer except the sliding area is almost constant.

[0062] Therefore, process (c) may be a process of measuring the thickness of the electrode mixture layer at a point 5 to 15 mm, 15 to 20 mm, 10 to 30 mm, or 20 to 30 mm from the boundary between the coated portion and the uncoated portion.

[0063] The process (d) will be described below. The process (d) is a process of calculating the ratio of the thickness of the electrode mixture layer of the positive electrode and the negative electrode measured in the process (b) to the thickness of the central portion of the positive electrode and the negative electrode measured in the process (c). The thickness T of the positive electrode mixture layer measured at the set position can be used. (P-n) With respect to the thickness T at the center portion of the positive electrode mixture layer measured by the above process (c) (P-center) The ratio (T (P-n) / T (P-center) ), and the thickness T of the positive electrode mixture layer measured at the set position (N-n) With respect to the thickness T of the central portion of the negative electrode mixture layer measured by process (c) (N-center) The ratio (T (N-center) / T (N-n) ) to manage the NP ratio at the local location.

[0064] Figure 3 is a flow chart of a method for managing a sliding area of ​​an electrode according to another embodiment of the present invention. Figure 3 The method for managing the sliding area of ​​the electrode of the present invention further includes a process (e) of calculating the ratio of the unit area capacity of the negative electrode to the unit area capacity of the positive electrode at the measurement position where the positive electrode faces the negative electrode (NP ratio). Process (e) includes using big data to calculate the NP ratio using the factor of the filling amount for the positive electrode and the negative electrode as the management object, and calculating the ratio of the thickness at the measurement position calculated by the above processes (a) to (d).

[0065] In a specific example, process (e) includes: process (e-1) for accumulating correlation data of each filling amount of the positive electrode and the negative electrode, the ratio of each thickness of the positive electrode and the negative electrode, and the NP ratio by repeating the above processes (a) to (d) while changing the measurement positions of the positive and negative electrodes of the sample; process (e-2) for deriving a correlation equation by analyzing the accumulated data; and process (e-3) for calculating the NP ratio by substituting the filling amount measured in process (b) and the ratio of the thickness calculated in process (d) into the correlation equation of the positive and negative electrodes to be managed.

[0066] First, in process (e-1), positive and negative electrodes having the same size as the positive and negative electrodes as the management object are prepared as samples, and processes (a) to (d) are repeated for these samples, and the filling amount and thickness ratio of each measurement position of each of the positive and negative electrodes are calculated and stored. In addition, data on the NP ratio is accumulated, which is calculated for each measurement position based on information on the ratio of the filling amount to the thickness obtained according to a known method. The NP ratio can be calculated according to the following 4 schemes: 1) positive electrode charge amount and negative electrode discharge amount; 2) positive electrode charge amount and negative electrode charge amount; 3) positive electrode discharge amount and negative electrode discharge amount; and 4) positive electrode discharge amount and negative electrode charge amount.

[0067] In addition, the process (e-2) includes deriving a correlation function between the ratio of each loading amount of the positive electrode and the negative electrode to each thickness of the positive electrode and the negative electrode and the NP ratio. At this time, the data can be analyzed using the r method, but the present invention is not limited to this example.

[0068] The process (e-3) includes calculating the NP ratio by substituting the ratio of the filling amount and thickness of each of the positive electrode and the negative electrode as the management object into the correlation equation derived in the process (e-2). Therefore, according to the present invention, since the NP ratio can be calculated by measuring the filling amount and thickness ratio of each position of the positive electrode and the negative electrode as the management object, it is possible to easily identify whether there is a reversal phenomenon of the NP ratio in the area including the sliding area that is difficult to manage.

[0069] In addition, by substituting the reference value of the designed SP ratio into the correlation function, which is a correlation function of the NP ratio derived by the process (e-2), the loading amount of each of the positive electrode and the negative electrode, and the ratio of the thickness of each of the positive electrode and the negative electrode, the maximum thickness of the positive electrode in the sliding region and the minimum thickness of the negative electrode in the sliding region can be derived. In addition, the reversal of the NP ratio can be prevented by allowing the thickness of the positive electrode mixture layer to be equal to or less than the maximum thickness and the thickness of the negative electrode mixture layer to be equal to or greater than the minimum thickness in the sliding region.

[0070] The above description is only an example of the technical concept of the present invention, and those skilled in the art to which the present invention belongs may make various modifications and changes without departing from the essential features of the present invention. Therefore, the drawings disclosed in the present invention are not intended to limit the technical concept of the present invention, but to describe the present invention, and the scope of the technical concept of the present invention is not limited by these drawings. The scope of protection of the present invention shall be interpreted by the following claims, and all technical concepts within the scope equivalent thereto shall be interpreted as included in the scope of the present invention.

Claims

1. A method for managing a sliding area of ​​an electrode, the method comprising: Process (a) of determining a specific area where a positive electrode and a negative electrode, which are management objects to be used in manufacturing an electrode assembly, face each other and setting a measurement position in the specific area; process (b), measuring the thickness and the filling amount of the electrode mixture layer of each of the positive electrode and the negative electrode at a set measurement position; process (c), measuring the thickness and the filling amount of the electrode mixture layer at the central portion of each of the positive electrode and the negative electrode; as well as Process (d) of calculating the ratio of the thickness of the electrode mixture layer of the positive electrode and the negative electrode measured in the process (b) relative to the thickness of the central portion measured in the process (c).

2. The method according to claim 1, further comprising: In process (e), the ratio of the capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode at the measurement position is calculated as the NP ratio.

3. The method according to claim 2, wherein the process (e) comprises: Process (e-1) of accumulating correlation data of the loading amount of each of the positive electrode and the negative electrode, the ratio of the thickness of each of the positive electrode and the negative electrode, and the NP ratio by repeating the process as claimed in claim 1 while changing the measurement positions of the positive electrode and the negative electrode of the sample; Process (e-2), deriving the correlation equation by analyzing the accumulated data; Process (e-3) calculating the NP ratio by substituting the ratio of the loading amount measured in the process (b) and the thickness calculated in the process (d) into the correlation equation of the positive electrode and the negative electrode as the management object.

4. The method according to claim 1, wherein the process (a) includes setting a measurement position in which a positive electrode faces a negative electrode in a sliding region.

5. The method according to claim 1, wherein the process (a) comprises setting a plurality of measuring positions (X1, X2, X3) at regular intervals along the width direction on the center line of the length direction of the electrode. 2... X n ).

6. The method according to claim 5, further comprising further measuring at the plurality of measurement positions (X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X12, X13, X14, X15, X16, X17, X18, X19, X20, X219, X22, X23, X24, X25 2... X n ) at each point, a plurality of measurement positions are set at regular intervals along the length direction of the electrode.

7. The method according to claim 1, wherein the process (a) comprises: (a-1) process, making an image of a plurality of vertical lines at regular intervals along the width direction of the electrode at a specific area; (a-2) process of making an image of a plurality of horizontal lines at regular intervals along the length direction in the set sliding area; (a-3) process of setting a plurality of rectangular areas formed by the intersection of the plurality of vertical lines and the plurality of horizontal lines as segmentation areas; as well as (a-4) process, setting a corresponding arbitrary point in the set segmented area as a measurement position.

8. The method according to claim 5, wherein a plurality of measurement positions (X1, X2) 2... X n ) are separated from each other by an interval of 0.05 to 0.2 mm. 9 . The method according to claim 1 , wherein the process (b) and the process (c) include measuring the thickness of the electrode mixture layer using a rotating caliper.

10. The method according to claim 1, wherein the process (b) comprises measuring a filling amount of the electrode mixture layer using a mesh gauge.

11. The method according to claim 1, wherein the positive electrode and the negative electrode of the process (b) are electrodes obtained by coating an electrode slurry containing an electrode active material on a current collector and then drying the electrode slurry. 12 . The method according to claim 11 , wherein the positive electrode and the negative electrode of the process (b) are electrodes before undergoing a rolling process.

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