Method for evaluating the ease of electrode detachment

Abstract

The method for evaluating the ease of electrode detachment according to the present invention comprises the steps of: attaching an electrode to a base material; cutting the electrode on the base material into a grid shape; attaching an adhesive tape to the electrode; peeling off the adhesive tape to peel the electrode from the base material; and evaluating the ease of detachment of the electrode according to the area of ​​the peeled electrode region. According to the present invention, the ease of detachment can be accurately evaluated without causing compression due to peeling in the active material layer of the electrode.

Description

Technology Field

[0001] The present invention relates to a method for evaluating the ease of detachment of an electrode.

[0002] More specifically, the present invention relates to a method for evaluating the ease of electrode detachment, which can more objectively measure the ease of active material crack growth that causes detachment by applying a cross-cut test to evaluate the ease of electrode detachment. Background Technology

[0004] With the increasing technological development and demand in the fields of mobile devices, automobiles, and energy storage devices, the demand for batteries as energy sources is rapidly rising. Among these secondary batteries, extensive research has been conducted on lithium-ion batteries, which feature high energy density and discharge voltage, and they have also been commercialized and are widely used.

[0005] A secondary battery consists of electrodes, a separator, and an electrolyte, and the electrodes are classified into positive and negative electrodes. The electrodes consist of a current collector (metal foil) and an active material layer coated on one or both sides of the current collector. The active material layer has constituent materials such as an active material, a conductive material, and a binder distributed three-dimensionally, and a number of pores exist in the gaps between them.

[0006] During the manufacturing and handling processes of secondary batteries, a phenomenon occurs in which a portion of the active material layer detaches from the electrode; this is referred to as "electrode detachment." If electrode detachment occurs, not only does the capacity of the battery cell decrease, but the detached clumps of active material can also cause a short circuit between the anode and cathode, thereby reducing the cell production yield. Therefore, the ease of electrode detachment is an important physical property that affects battery quality and production yield.

[0007] Conventionally, to evaluate the ease of detachment of such electrodes, a 90-degree peel test, which is used to measure the adhesion strength of electrodes, has been performed.

[0008] Figure 1 is a schematic diagram showing the 90-degree peel test process of an electrode.

[0009] Specifically, a sample is prepared by cutting the electrode to a predetermined size, and the adhesive strength or ease of detachment of the electrode is evaluated by measuring the force (gf / mm) applied until the tape detaches from the sample while pulling one end of the sample electrode with a gripper such as a universal material tester (UTM) at a constant speed and a peeling angle of 90 degrees. The electrode (1) in FIG. 1 represents a double-sided electrode in which active material layers (1a, 1c) are formed respectively on the upper and lower parts of a current collector foil (1b).

[0010] Figure 2 shows an example of a force-tension graph measured by such a peel test. In the graph shown, points where the magnitude of the force measured over time becomes flat are identified, and the average value of these points is calculated to evaluate the ease of detachment.

[0011] However, the above peel test has the following problems.

[0012] First, when one end of the electrode is pulled, the upper region of the pulled electrode is compressed, creating a compression zone. Since a significant portion of the force measured by the universal testing machine is consumed in compressing the electrode, the force measured by the machine may not accurately reflect the detachment tendency.

[0013] Second, as described above, since the occurrence of a compression region on the upper part of the electrode affects the force measured by the tester, the magnitude of the measured force may be more sensitive to the thickness or porosity of the electrode active material layer or the strength of the active material rather than the 'ease of crack growth'.

[0014] Due to the aforementioned issues, it is difficult to accurately predict the tendency of electrode detachment using peel tests. In fact, when the ease of detachment was evaluated by peel tests using two electrodes with different degrees of detachment, no significant difference was found.

[0016] Therefore, it is desirable to develop an electrode detachment ease evaluation technology that can reflect the electrode's detachment tendency or ease of crack growth. Prior art literature

[0018] Korean Patent Publication No. 10-2020-0027693 The problem to be solved

[0019] The present invention was devised to solve the above-mentioned problem and aims to provide a method for evaluating the ease of electrode detachment that can measure the ease of crack growth of the electrode active material without causing a compression region in a part of the upper part of the electrode during electrode peeling. means of solving the problem

[0021] The method for evaluating the ease of electrode detachment according to the present invention for solving the above problem comprises: a step of attaching an electrode to a base material; a step of cutting the electrode on the base material into a grid shape; a step of attaching an adhesive tape to the electrode; a step of peeling off the adhesive tape to peel off the electrode from the base material; and a step of evaluating the ease of detachment of the electrode according to the area of ​​the peeled electrode region.

[0022] As an example, the electrode can be attached to a base material by means of double-sided tape to form a base material-double-sided tape-electrode composite.

[0023] As an example, the method may further include the step of applying pressure to the base material-double-sided tape-electrode composite at a predetermined pressure.

[0024] As a preferred example, when the base material-double-sided tape-electrode composite is pressurized with a predetermined pressure, heat can be simultaneously applied to heat and pressurize the composite.

[0025] As an example, the above-mentioned base material-double-sided tape-electrode composite can be placed between two release films to press the release films and the composite.

[0026] After pressing the release film and the composite, the release film is removed, and the electrode of the pressurized base material-double-sided tape-electrode composite can be cut into a grid shape.

[0027] As a specific example, the above-mentioned predetermined pressure can be selected in the range of 0.05 to 10 MPa.

[0028] As another specific example, the heating temperature of the above base material-double-sided tape-electrode composite can be selected in the range of 40 to 130°C.

[0029] As an example, the electrode is a single-sided electrode in which an active material layer is coated on one side of a current collector foil, and the side of the single-sided electrode coated with the active material layer can be attached to a base material by the double-sided tape.

[0030] As another example, the electrode is a double-sided electrode in which an active material layer is coated on both sides of a current collector foil, and the side of the active material layer coated on one side of the double-sided electrode can be attached to the base material by the double-sided tape. Effects of the invention

[0032] According to the present invention, the ease of detachment can be accurately evaluated without causing compression due to peeling in the active material layer of the electrode. Brief explanation of the drawing

[0034] Figure 1 is a schematic diagram showing the 90-degree peel test process of an electrode. Figure 2 shows an example of a force-tensile graph measured by a peel test. FIG. 3 is a flowchart illustrating the method for evaluating the ease of electrode detachment according to the present invention. Figure 4 is a photograph showing the step of forming a base material-double-sided tape-electrode composite by the evaluation method of the present invention. Figure 5 is a photograph showing the process of cutting a base material-double-sided tape-electrode composite into a grid shape and attaching and peeling off the adhesive tape. FIG. 6 is a schematic diagram illustrating the method for evaluating the ease of electrode detachment according to the present invention. FIG. 7 is a flowchart illustrating a method for evaluating electrode detachment ease according to an embodiment of the present invention. Figure 8 is a view of the base material-double-sided tape-electrode composite from the base material side, showing photographs before heating and pressurizing (Figure 8(a)) and after heating and pressurizing (Figure 8(b)). Figure 9 is a photograph showing the ease of detachment of the electrode of Example 1. Figure 10 is a drawing of the base material-double-sided tape-electrode composite of Example 2 viewed from the base material side and a photograph showing the ease of detachment of the electrode. Figure 11 is a drawing of the base material-double-sided tape-electrode composite of Comparative Example 2 viewed from the base material side and a photograph showing the ease of detachment of the electrode. Specific details for implementing the invention

[0035] The present invention will be described in detail below. Prior to this, terms or words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor may appropriately define the concepts of terms to best describe their invention, they must be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0036] In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "immediately above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "immediately below" the other part, but also cases where there is another part in between. Additionally, in this application, being placed "on" may include cases where it is placed on the lower part as well as on the upper part.

[0038] FIG. 3 is a flowchart illustrating the method for evaluating the ease of electrode detachment according to the present invention.

[0039] The method for evaluating the ease of electrode detachment according to the present invention comprises: (a) attaching an electrode to a base material; (b) cutting the electrode on the base material into a grid shape; (c) attaching an adhesive tape to the electrode; (d) peeling off the adhesive tape to peel the electrode from the base material; and (e) evaluating the ease of detachment of the electrode according to the area of ​​the peeled electrode region.

[0040] First, to evaluate the ease of electrode detachment, an electrode is attached to the base material (Step (a)). In this case, it is preferable for the electrode to be attached to the base material using double-sided tape. To attach the electrode directly to the base material, adhesive must be applied to the electrode or the base material; however, since the adhesive may not be applied uniformly depending on the surface condition of the electrode or the base material, and direct adhesion may be difficult depending on the type of base material, it is necessary to attach the electrode to the base material using double-sided tape. By selecting a double-sided tape that adheres well to both the base material and the electrode, the electrode can be easily attached to the base material without the need to apply adhesive to the electrode or the base material individually.

[0041] Slide glass can be used as the base material. When using slide glass, it is possible to clearly observe whether bubbles are present through the back surface of the slide glass to which the electrode is attached.

[0042] FIG. 4 is a photograph showing the step of forming a base material-double-sided tape-electrode composite by the evaluation method of the present invention. As shown in FIG. 4(a), an electrode (negative electrode) (1), a double-sided tape (2), and a slide glass (3) are prepared, and the double-sided tape (2) and the electrode (1) are sequentially attached to the slide glass (3) to form a base material (slide glass)-double-sided tape-electrode composite (10) as shown in FIG. 4(b). In this specification, "composite" refers to a state in which the electrode is attached to the base material through the double-sided tape to physically form an integral unit. Since the state is formed as an integral unit by the adhesive force of the double-sided tape, it does not mean a state in which the electrode forms a chemical bond with the base material or the double-sided tape.

[0044] Next, the electrode on the base material is cut into a grid shape (step (b)).

[0045] When cutting the electrode, a grid shape must be formed at uniform intervals. To this end, a knife from a commercially available cross-cut test kit can be used. For example, if a six-line pattern at regular intervals is drawn twice with the knife, the electrode can be cut into a grid shape of 25 sections.

[0046] FIG. 5 is a photograph showing the process of cutting a base material-double-sided tape-electrode composite (10) into a grid shape and attaching and peeling off an adhesive tape. FIG. 5(a) clearly shows 25 grid-shaped cut sections (11).

[0047] Afterward, an adhesive tape (20) is attached to the electrode (1) (step (c)), and the adhesive tape (20) is peeled off from the top to peel off the electrode (1) from the base material (3) (step (d)). FIG. 5(b) shows the state in which the adhesive tape (20) is attached to the electrode (1), and FIG. 5(c) shows the state in which the electrode is peeled off after the adhesive tape (20) is peeled off.

[0048] After peeling off the electrode, the ease of detachment of the electrode is evaluated according to the area of ​​the peeled electrode region (21) (step (e)). The present invention applies the cross-cut adhesion test, which is a test of the adhesion strength of a coating film, to the evaluation of the ease of detachment of the electrode. Accordingly, the ease of detachment can be evaluated according to the evaluation class 0 to 5 of ISO 2409, an international standard for cross-cut adhesion tests. The closer the evaluation class is to 0, the more the squares of the grid after peeling are not separated, which means that the active material of the electrode is difficult to detach from the current collector. Therefore, the lower the evaluation class, the less easy it is to detach, and the higher the evaluation class, the easier it is to detach the electrode.

[0049] After the step of cutting the electrode into a grid shape, debris of the active material layer may accumulate on the cut surface, so the debris can be removed by rubbing the cut surface with a brush.

[0050] FIG. 6 is a schematic diagram illustrating the method for evaluating the ease of electrode detachment according to the present invention.

[0051] In order to avoid causing compression due to peeling in the active material layer of the electrode (1) as in the conventional method, the electrode (1) is cut into a grid shape as shown in FIG. 6. When an adhesive tape is attached to the electrode cut into a grid shape and peeled off, the electrode is peeled off by receiving an even force from above. Therefore, since a portion of the upper active material layer (1a) of the electrode is not compressed during peeling as in the conventional method, the ease of electrode detachment can be determined more accurately. In addition, since the active material layer (1c) is peeled off by a peeling force from above in a direction perpendicular to the electrode, it peels off in the same direction as the crack growth direction that actually occurs in the electrode. Therefore, the ease of crack growth or ease of detachment of the actual electrode can be evaluated more accurately.

[0052] The electrode (1) shown in FIG. 6 is a double-sided electrode in which active material layers (1a, 1c) are coated on both sides of a current collector foil (1b). During the peel test, the side of the active material layer coating on one side of the double-sided electrode is attached to the base material (3) by means of double-sided tape (2).

[0053] Meanwhile, the peel test of the present invention can also be applied to a single-sided electrode in which an active material layer is coated on one side of a current collector foil. In this case, the side of the single-sided electrode coated with the active material layer is attached to the base material using double-sided tape. As shown in FIG. 6, it can be seen that removing the active material layer on the upper side of the current collector foil results in a single-sided electrode; therefore, the ease of detachment of the electrode can also be evaluated by peeling the current collector foil from the lower active material layer using adhesive tape.

[0055] FIG. 7 is a flowchart illustrating a method for evaluating electrode detachment ease according to an embodiment of the present invention.

[0056] The present embodiment relates to an evaluation method for heating and pressurizing a composite when an electrode is attached to a base material by means of double-sided tape to form a base material-double-sided tape-electrode composite.

[0057] The thickness of the electrodes (positive and negative electrodes) of a lithium-ion battery, including the current collector, is approximately 100 to 300 μm, and the thickness of the adhesive tape applied during the peel test is similar. Therefore, when peeling off the electrodes with the adhesive tape, there is a possibility that the electrodes may become twisted and deformed. In this case, a part of the grid-shaped electrode may be distorted, making it difficult to perform the peel test accurately.

[0058] In particular, if a peel test is performed on the base material-double-sided tape-electrode composite in its original state, a significant amount of debris falls off the edges of the cut surface, making it difficult to clearly distinguish the grade of ease of detachment. Furthermore, this composite contains a large amount of air bubbles; during a cross-cut, debris from electrodes not firmly fixed to the base material is generated within these bubbles, which also hinders the evaluation of ease of detachment.

[0059] This embodiment is characterized by the fact that, taking these points into consideration, a double-sided tape and an electrode are sequentially attached to a base material to form a base material-double-sided tape-electrode composite, and the composite is then pressed to suppress the aforementioned debris and bubble generation. In addition, when the composite is pressed and the electrode is firmly fixed to the base material, the possibility of the electrode being partially twisted or deformed when the electrode is removed with the adhesive tape is significantly reduced. Therefore, this embodiment is significant in that it implements a base material-double-sided tape-electrode composite for evaluating electrode detachability in an optimal state for a cross-cut test.

[0060] The process of sequentially attaching double-sided tape and electrodes to the base material to form a base material-double-sided tape-electrode composite in step (a) of Fig. 7, and the process of cutting into a grid shape, attaching and peeling adhesive tape, and evaluating the ease of detaching the electrode in steps (b) to (e) are identical to the evaluation method of Fig. 3. The difference is that steps (a-1) to (a-3) have been added.

[0061] The predetermined pressure applied to the base material-double-sided tape-electrode composite can be set differently depending on the type of electrode (anode or cathode) or the type, thickness, porosity, etc. of the active material layer on the electrode. For example, the composite can be pressurized by selecting an appropriate pressure according to the electrode under test within the range of 0.05 to 10 MPa. As a pressure capable of eliminating bubbles, it needs to be at least 0.05 MPa. In addition, considering the upper process limit conditions during the electrode lamination process, it is preferable that the pressurizing pressure be 10 MPa or less. In particular, it is desirable to pressurize the composite at a pressure in the range of 0.2 to 2.5 MPa.

[0062] If an appropriate pressure within the above range is selected, the composite may be pressurized at room temperature. However, it is desirable to heat it to an appropriate temperature to remove bubbles more effectively and quickly. That is, heat and pressure can be applied to the composite to create an optimal condition for the cross-cut test. For example, when pressurizing the composite, it may be heated to a temperature in the range of 40 to 130°C. The above temperature can be appropriately selected considering the relationship with the pressurizing pressure. When pressurizing with relatively strong pressure, it may be heated to a temperature of 40°C. In addition, considering the upper process limit conditions during the electrode lamination process, it is desirable to heat it to 130°C or lower. A more desirable heating temperature range is 50 to 90°C.

[0063] In this embodiment, to prevent damage to the composite and to enable more uniform heating and pressing when heating and pressing the base material-double-sided tape-electrode composite, the composite is placed between two release films (step (a-1)) and the release films and the composite are heated and pressed (step (a-2)). After heating and pressing, the release films are removed so that only the composite can be cut into a grid shape (steps (a-3) and (b)).

[0064] When a composite from which bubbles have been removed by heating and pressurizing is cut and peeled off with adhesive tape, the ease of detachment of the electrode can be evaluated more accurately as described below.

[0065] FIG. 8 is a drawing of the base material side (the back side (10a) of the composite) of the base material-double-sided tape-electrode composite (10), and is a photograph of the composite before heating and pressurizing (Fig. 8(a)) and after heating and pressurizing (Fig. 8(b)).

[0066] As clearly shown in FIG. 8(a), a large amount of bubbles (P) are mixed into the composite (10) that is not heated or pressurized. On the other hand, as clearly shown in FIG. 8(b), it can be seen that almost no bubbles (P) are observed in the composite that is heated or pressurized.

[0068] Examples

[0070] Example 1

[0071] Two cathodes of the same grade with a thickness of 182 μm, Lot #1 and Lot #2 with different levels of delamination (another cathode with an active material layer coated on both sides of an 8 μm thick Cu foil as a current collector, with a mass ratio of active material:conductive material:binder of 96.5:0.5:3), were prepared and each was stamped to a size of 100 mm × 20 mm.

[0072] In addition, a double-sided tape (3M 9070 non-woven double-sided tape) with a thickness of 0.15 mm and a width of 25 mm and a slide glass with a thickness of 1 mm and an area of ​​26 mm × 76 mm were prepared as the base material.

[0073] A slide glass-double-sided tape-electrode composite was made by sequentially attaching double-sided tape and an electrode to the slide glass.

[0074] This composite was placed between two release films (thickness 0.4 mm) made of polypropylene (PP) material, and the release films and the composite were placed in a laminator (GMP EXCELAM II-355) and heated and pressurized at 70°C and 0.5 MPa.

[0075] After heating and pressurizing, the release film was removed, and the electrode on the slide glass-double-sided tape-electrode composite was cut twice with a knife (for TQC Cross Cut Adhesion Test) at 1.5 mm intervals to create a grid-shaped electrode of 25 squares.

[0076] If an adhesive tape (Post-it) is attached to this grid-shaped electrode and the adhesive tape is peeled off, the electrode is peeled off.

[0078] Figure 9 is a photograph showing the ease of detachment of the electrode of Example 1.

[0079] When evaluating the ease of detachment of the peeled area according to the ISO2409 evaluation grades after peeling, the ease of detachment can be evaluated as Grade 4 (cathode of Lot #1) and Grade 5 (cathode of Lot #2) as shown in Fig. 9, and a significant difference between the two cathodes was confirmed. That is, Grade 4 was less peeled than the other two cathodes, and from this, it can be seen that the detachment of the Grade 4 cathode is not as easy as that of the Grade 5 cathode.

[0081] Comparative Example 1

[0082] Two cathodes, a slide glass, and double-sided tape were prepared in the same manner as in Example 1. The double-sided tape and the cathode were sequentially attached to the slide glass to form a slide glass-double-sided tape-cathode composite, and this was heated and pressurized in a laminator under the same conditions as in Example 1.

[0083] One end of the cathode from this composite was gripped with a universal testing machine gripper and pulled at a speed of 100 mm / min to perform a 90-degree peel test. The average value of the flat portion was calculated from the tensile force graph measured according to the peel test time.

[0084] The tensile strength (peel strength) of the cathode measured by repeating the above test twice is as follows.

[0086] - Lot #1 Cathode: 1st test tensile strength 22.9 gf / 20mm, 2nd test tensile strength 29.7 gf / 20mm

[0087] -Lot #2 Cathode: 1st test tensile strength 25.5 gf / 20mm, 2nd test tensile strength 27.2 gf / 20mm

[0089] As described above, since the cathodes of Comparative Example 1 measured by the peel test did not show a significant difference in tensile strength between lots, the ease of detachment could not be clearly determined.

[0091] Example 2

[0092] A cathode with a thickness of 194 μm (a cathode with an active material layer coated on both sides of an 8 μm thick Cu foil as a current collector, wherein the ratio of active material:conductive material:binder is 96:1:3 by mass ratio) was prepared and each was stamped into a size of 100 mm × 25 mm.

[0093] A slide glass-double-sided tape-electrode composite was made by attaching the above cathode to the same double-sided tape and slide glass as in Example 1.

[0094] This composite was placed between two release films (thickness 0.4 mm) made of polypropylene (PP) material, and the release films and the composite were placed in a laminator (GMP EXCELAM II-355) and heated and pressurized at 70°C and 0.5 MPa.

[0095] Figure 10 is a drawing of the base material-double-sided tape-electrode composite of Example 2 viewed from the base material side and a photograph showing the ease of detachment of the electrode.

[0096] As shown in Fig. 10(a), when viewing the heated and pressurized composite of Example 2 from the slide glass side, it can be seen that almost no bubbles are generated.

[0097] After heating and pressurizing, remove the release film and use a knife (for TQC Cross Cut Adhesion Test) to draw six lines twice at 1.5 mm intervals on the electrodes on the slide glass-double-sided tape-electrode composite to create a grid-shaped electrode of 25 squares.

[0098] When an adhesive tape is attached and peeled off on this grid-shaped electrode and the peeling area is evaluated for ease of detachment according to the ISO2409 evaluation grade of FIG. 10(c), the ease of detachment of the electrode of Example 2 can be evaluated as it corresponds to grade 3 as shown in FIG. 10(b).

[0100] Comparative Example 2

[0101] A cathode, a slide glass, and double-sided tape were prepared in the same manner as in Example 2. A slide glass-double-sided tape-cathode composite was formed by sequentially attaching the double-sided tape and the cathode to the slide glass. In Comparative Example 2, the heating and pressurizing process as in Example 2 was omitted.

[0102] Figure 11 is a drawing of the base material-double-sided tape-electrode composite of Comparative Example 2 viewed from the base material side and a photograph showing the ease of detachment of the electrode.

[0103] As shown in Fig. 11(a), it can be seen that a large amount of bubbles are formed in the composite that is not heated or pressurized.

[0104] When the electrodes are cut into a grid shape from this composite in the same way as in Example 2, and the adhesive tape is attached and peeled off to evaluate the peeled area, it is as shown in Fig. 11(b).

[0105] As shown in Fig. 11(b), when the base material-double-sided tape-electrode composite is not heated or pressurized, a large amount of debris falls off the edges of the cut surface during the peel test, making it difficult to clearly distinguish whether the peelability grade is 3 or 4. In addition, it is observed that a large amount of debris is generated as the debris of the negative active material layer, which is not firmly fixed to the slide glass, deforms upon cutting.

[0107] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0109] 1a: Upper active material layer 1b: Whole house foil 1c: Lower active material layer 1: Electrode 2: Double-sided tape 3: Slide Glass 10: Slide glass-double-sided tape-base material composite 10a: Back side of the complex P: bubbles 11: Grid-shaped cut section 20: Adhesive tape (adhesive sheet) 21: Electrode peeling area

Claims

Claim 1 A method for evaluating the ease of detaching an electrode, comprising the steps of: attaching an electrode to a base material; cutting the electrode on the base material into a grid shape; attaching an adhesive tape to the electrode; peeling off the adhesive tape to peel the electrode from the base material; and evaluating the ease of detaching the electrode according to the area of ​​the peeled electrode region; attaching the electrode to the base material by means of double-sided tape to form a base material-double-sided tape-electrode composite; further comprising the step of applying pressure to the base material-double-sided tape-electrode composite to suppress the generation of bubbles within the base material-double-sided tape-electrode composite, and cutting the electrode of the pressured base material-double-sided tape-electrode composite into a grid shape. Claim 2 delete Claim 3 delete Claim 4 A method for evaluating the ease of electrode detachment according to claim 1, wherein heat is simultaneously applied to heat and pressurize the composite when the base material-double-sided tape-electrode composite is pressed with a predetermined pressure. Claim 5 A method for evaluating the ease of electrode detachment according to claim 1, wherein the base material-double-sided tape-electrode composite is placed between two release films and the release films and the composite are pressed. Claim 6 A method for evaluating electrode detachability according to claim 5, wherein after pressurizing the release film and the composite, the release film is removed, and the electrode of the pressurized base material-double-sided tape-electrode composite is cut into a grid shape. Claim 7 A method for evaluating electrode detachment ease, wherein the predetermined pressure is selected in the range of 0.05 to 10 MPa in claim 1. Claim 8 In claim 4, the heating temperature of the base material-double-sided tape-electrode composite is selected in the range of 40 to 130℃ for an evaluation method of electrode detachability. Claim 9 In claim 1, the electrode is a single-sided electrode having an active material layer coated on one side of a current collector foil, and the electrode detachability evaluation method is a method of attaching the side of the active material layer coated on the single-sided electrode to a base material by means of the double-sided tape. Claim 10 In claim 1, the electrode is a double-sided electrode having an active material layer coated on both sides of a current collector foil, and a method for evaluating the ease of electrode detachment in which the side of the active material layer coated on one side of the double-sided electrode is attached to a base material by the double-sided tape. Claim 11 A method for evaluating electrode detachability according to claim 1, further comprising the step of rubbing the cut surface with a brush after the cutting step. Claim 12 A method for evaluating the ease of electrode detachment, wherein the base material is a slide glass, in claim 1.

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