Method for removing one electrode layer from a double-sided electrode

Abstract

The present invention provides a method for removing one side of an electrode layer of a double-sided electrode, which comprises interposing a double-sided electrode between an upper plate having an opening communicating with the top and bottom and a lower plate having a recessed portion that is open on one side and closed on the other side, placing the plate assembly, in which the upper plate and the lower plate are joined together with the double-sided electrode interposed, in an NMP (N-methyl-2-pyrrolidone) water bath and applying ultrasonic waves to the plate assembly.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167845, filed December 5, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for removing an electrode layer on one side from a double-sided electrode. [Background technology]

[0003] The rapid increase in fossil fuel use has led to an increasing demand for alternative and clean energy, and one of the most actively researched areas as part of this is the field of electrochemical power generation and storage.

[0004] Currently, a typical example of an electrochemical element that utilizes such electrochemical energy is a secondary battery, and the range of its use is expanding more and more.

[0005] Recently, with technological development and increasing demand for portable devices such as portable computers, mobile phones, and cameras, the demand for secondary batteries as energy sources has increased dramatically. Among such secondary batteries, various researches have been conducted on lithium secondary batteries, which exhibit high charge / discharge characteristics and life characteristics and are environmentally friendly, and they have been commercialized and widely used.

[0006] Meanwhile, such lithium secondary batteries are disassembled for various reasons before, during, or after use, to remove the electrode layers from the electrodes, and then recycled.

[0007] FIG. 1 shows, as an example, a schematic diagram of a conventional method for removing an electrode layer 12 from an electrode 10.

[0008] Referring to Figure 1, ultrasonic waves, which cause little damage, have been used in the past to peel off only the electrode layer 12 from the electrode current collector 11. Specifically, an ultrasonic wave generating device such as an ultrasonic horn 20 is used to apply ultrasonic waves to the surface of the electrode layer 12, creating small bubbles that destroy the coating, and no solvent is used.

[0009] However, in this method, the double-sided electrode layer 12 is completely destroyed, making it difficult to use as a single-sided electrode.

[0010] However, for example, in a typical full cell, it is difficult to analyze the potential of the positive and negative electrodes. Therefore, when an LTO electrode is inserted between the three-electrode cell and the potential of the positive and negative electrodes is analyzed, one positive electrode and one negative electrode are used on one side of the three-electrode cell to reduce the risk of resistance reduction and capacity loss.

[0011] In response to this, a need has arisen for a method to remove one electrode layer from a double-sided electrode. However, when removing one electrode layer from a double-sided electrode to manufacture a single-sided electrode, workers typically do so manually using a solvent and wafer towels. This can lead to problems such as damage to the foil by the worker and the solvent penetrating into the electrode surface.

[0012] Therefore, there is an urgent need to develop a technology that can solve these problems and produce single-sided electrodes by recycling double-sided electrodes without damaging the surface that is being used. Summary of the Invention [Problem to be solved by the invention]

[0013] The problem to be solved by the present invention is to provide a method for removing an electrode layer on one side from a double-sided electrode without damaging the electrode layer on the other side while eliminating deviations caused by the operator. [Means for solving the problem]

[0014] To achieve the above object, a method for removing one side of an electrode layer according to one embodiment of the present invention is a method for removing one side of an electrode layer of a double-sided electrode, and is characterized by interposing a double-sided electrode between an upper plate having a structure in which an opening communicating vertically is formed and a lower plate having a structure in which a recess having an open portion on one side and a closed portion on the other side is formed, and placing the plate assembly in which the upper plate and the lower plate are bonded together with the double-sided electrode interposed in an NMP (N-methyl-2-pyrrolidone) water bath and applying ultrasonic waves to the plate assembly.

[0015] In this case, when the double-sided electrode is interposed between the upper plate and the lower plate, the opening of the upper plate and the recessed portion of the lower plate are entirely covered, and the area of ​​the opening and the recessed portion may be smaller than the area of ​​the double-sided electrode excluding the tabs, and more specifically, may be 90% to 98% of the area of ​​the double-sided electrode excluding the tabs.

[0016] In one specific example, the inner surface of the upper plate facing the lower plate may include a groove having a shape corresponding to the frame shape of the upper plate, and a rubber ring may be fitted in the groove.

[0017] Here, the rubber ring may be configured to apply pressure to the entire edge of the double-sided electrodes when the double-sided electrodes are coupled.

[0018] In one specific example, the upper plate and the lower plate may be mechanically connectable and disassembleable, and more specifically, the upper plate and the lower plate may be connected by fastening bolts inserted into fastening holes.

[0019] Meanwhile, when the plate assembly is placed in an N-methylpyrrolidone (NMP) water bath, the NMP solvent may not be present between the double-sided electrode and the lower plate.

[0020] In one specific example, the temperature of the NMP solvent in the NMP water tank may be 25 to 60 degrees Celsius, and the NMP water tank may be provided with two or more ultrasonic horns.

[0021] In one specific example, ultrasonic waves are applied to the plate assembly while it is completely immersed in the NMP solvent, and the ultrasonic waves may be applied for 5 minutes to 30 minutes at a frequency of 10 kHz to 500 kHz.

[0022] Furthermore, the method for removing the one-side electrode layer may include a step of drying the one-side electrode from which the one-side electrode layer has been removed after applying the ultrasonic waves. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram illustrating an example of a conventional method for removing an electrode layer from a double-sided electrode. [Figure 2] 1 is an exploded perspective view of a plate used in a method for removing a one-side electrode layer according to an embodiment of the present invention; [Figure 3] FIG. 2 is a top view of a plate assembly according to one embodiment of the present invention. [Figure 4] FIG. 4 is a one-side view of the plate assembly cut along line L in FIG. 3. [Figure 5] FIG. 2 is a schematic view of the inner surface of an upper plate according to an embodiment of the present invention. [Figure 6] 1 is a schematic diagram illustrating a method for removing a one-side electrode layer according to an embodiment of the present invention; [Figure 7] 1 is a schematic diagram illustrating a mechanism by which a one-side electrode layer is removed from a double-sided electrode. DETAILED DESCRIPTION OF THE INVENTION

[0024] The terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed in a meaning and concept that is consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to best explain his / her invention.

[0025] The terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise.

[0026] Furthermore, throughout this specification, when a part "comprises" a certain component, it does not mean that it excludes other components, but that it may further include other components, unless otherwise specified.

[0027] According to one embodiment of the present invention, there is provided a method for removing a one-sided electrode layer, which includes interposing a double-sided electrode between an upper plate having a structure in which an opening communicating vertically is formed and a lower plate having a structure in which a recess that is open on one side and closed on the other side is formed, and placing the plate assembly in a N-methyl-2-pyrrolidone (NMP) bath and applying ultrasonic waves to the plate assembly.

[0028] Hereinafter, a method for removing a one-side electrode layer according to an embodiment of the present invention will be described in more detail with reference to the accompanying drawings. However, the following description of the drawings is by way of an embodiment and is not intended to limit the scope of the present invention.

[0029] First, FIGS. 2 to 4 schematically show a plate assembly used in the present invention.

[0030] Specifically, the drawings show an exploded perspective view of a plate used in a method for removing a single-sided electrode layer according to one embodiment of the present invention, FIG. 3 shows a top view of a plate assembly in which double-sided electrodes are bonded to the plate, and FIG. 4 shows a single-sided view of the plate assembly.

[0031] 2 to 4, the plate assembly 100 has a structure in which a double-sided electrode 130 is interposed between an upper plate 110 and a lower plate 120. As shown in FIG.

[0032] Specifically, the upper plate 110 has a structure in which an opening 111 that is connected vertically is formed, and the lower plate 120 has a structure in which one side is open and the other side is formed with a closed recess 121. Here, the opening 111 of the upper plate 110 and the recess 121 of the lower plate 120 have the same area, and when they are combined with the double-sided electrode 130, the opening 111 and the recess 121 are combined so that they are positioned at the same position.

[0033] Here, the upper plate 110 and the lower plate 120 can be mechanically coupled and disassembled, so that the double-sided electrode 130 can be interposed between the upper plate 110 and the lower plate 120 or removed.

[0034] At this time, the method of mechanically connecting and disconnecting is not limited as long as it is a form that can be repeatedly performed, and for example, the plates 110 and 120 can be connected by fastening bolts 140 inserted into fastening holes 113 and 123. In this structure, the plates 110 and 120 can be used repeatedly.

[0035] Specifically, the upper plate 110 and the lower plate 120 may include fastening holes 113, 123, and the plate assembly 100 can be manufactured by inserting the fastening bolts 140 into the fastening holes 113, 123 with the double-sided electrode 130 interposed therebetween so that the electrode layer 133 is exposed in the opening 111 and the recess 121.

[0036] After removing the one-side electrode layer 133, the fastening bolts 140 are again removed from the fastening holes 113 and 123 to separate the upper plate 110 and the lower plate 120, and the one-side electrode from which the one-side electrode layer 133 has been removed can be separated and removed from the plate assembly 100.

[0037] Here, the fastening holes 113 and 123 may be formed at positions that communicate with each other so that they can be fastened by one fastening bolt 140 at a time.

[0038] On the other hand, since the double-sided electrode 130 must be interposed and fixed between the upper plate 110 and the lower plate 120, when the double-sided electrode 130 is interposed between the upper plate 110 and the lower plate 120, the area (S1) of the opening 111 and the recessed portion 121 is smaller than the area (S2) of the double-sided electrode 130 excluding the tabs 131 and 132 so that the opening 111 of the upper plate 110 and the recessed portion 121 of the lower plate 120 are completely covered.

[0039] In detail, the area (S1) of the opening 111 and the recess 121 may be 90% to 98% of the area (S2) of the double-sided electrode 130 excluding the tabs 131 and 132, more specifically, 92% to 98%, and even more specifically, 92% to 95%.

[0040] If the size of the opening 111 and the depression 121 is too small beyond the above range, it is likely that the electrode layer 133 will not be removed, and if the size of the opening 111 and the depression 121 is too large, the double-sided electrode 130 may be sandwiched between the upper plate 110 and the lower plate 120 and not fixed, which is not preferable.

[0041] Furthermore, in order to more firmly fix the double-sided electrode 130 so that it does not move between the upper plate 110 and the lower plate 120, a groove is formed on the inner surface of the upper plate 110 facing the lower plate 120 in a shape corresponding to the frame shape of the upper plate 110, and a rubber ring may be attached to the groove.

[0042] To explain this, the inner surface of the upper plate 110 is shown schematically in FIG.

[0043] Referring to FIG. 5, the upper plate 110s has an opening 111 formed so as to be connected vertically and has a frame shape, and a rubber ring 112 is attached to a groove (not shown) of a shape corresponding to the frame shape.

[0044] The rubber ring 112 can then apply pressure to the entire edge of the double-sided electrode 130 when the double-sided electrode 130 is interposed between the rubber ring 112 and the lower plate 120. This can more firmly hold the edge of the double-sided electrode 130, preventing movement of the double-sided electrode 130, and subsequently preventing the NMP solvent from burning and transferring to the electrode layer, effectively preventing damage to the other electrode layer during the removal of the one-sided electrode layer 133.

[0045] Therefore, a method for removing the one-side electrode layer 133 using such a plate assembly 100 will be described below.

[0046] FIG. 6 is a schematic diagram showing a method for removing one surface electrode layer according to an embodiment of the present invention, and FIG. 7 is a schematic diagram showing the mechanism by which the one surface electrode layer is removed.

[0047] 6 and 7 together with FIG. 3 and FIG. 4, in the plate assembly 100, the electrode layer 133 on one side of the double-sided electrode 130 is exposed to the outside through the opening 111 in the upper plate 110, and the electrode layer 134 on the other side is sealed by the lower plate 120.

[0048] Unlike FIG. 4, the plate assembly 100 shown in FIG. 6 is a side view rather than a cross-sectional view, and does not show the shape in which the electrode layer 133 is exposed. When viewed from above, the plate assembly 100 is inserted into the NMP tank 150 with one side of the electrode layer 133 exposed, as shown in FIG. 3.

[0049] Therefore, when the plate assembly 100 is inserted into the NMP water tank 150 and comes into contact with the NMP solvent 151, only the electrode layer 133 on one side of the double-sided electrode 130 exposed through the opening 111 of the upper plate 110 comes into contact with the NMP solvent 151, while the electrode layer 134 on the other side facing the lower plate 120 is sealed by the lower plate 120 and does not come into contact with the NMP solvent 151. In other words, there is no NMP solvent 151 between the double-sided electrode 130 and the lower plate 120.

[0050] At this time, the temperature of the NMP solvent 151 in the NMP water tank 150 may be 25 to 60 degrees Celsius, specifically 30 to 60 degrees Celsius, and more specifically 45 to 50 degrees Celsius.

[0051] If the temperature is too high beyond this range, the heat may be transferred to the other side of the double-sided electrode 130, which may cause oxidation of the current collector, which is undesirable.

[0052] Thereafter, the plate assembly 100 is placed in an NMP water bath 150, and ultrasonic waves are applied to remove the electrode layer 133 on one side. At this time, since the electrode layer 133 on one side must be in complete contact with the NMP solvent 151, ultrasonic waves can be applied to the plate assembly 100 while it is completely immersed in the NMP solvent 151.

[0053] Therefore, two or more ultrasonic horns 152 may be formed in the NMP water tank 150, and ultrasonic waves may be applied to the NMP solvent 151 by the ultrasonic horns 152.

[0054] Here, ultrasonic waves can be applied at a frequency of 10 kHz to 500 kHz for 5 to 30 minutes, and more specifically, ultrasonic waves can be applied at a frequency of 20 kHz to 50 kHz for 10 to 20 minutes.

[0055] If the voltage is applied for a very short time or at a frequency that is too low, the electrode layer 133 may not be completely removed, and if the voltage is applied for a very long time or at a frequency that is too high, the surface of the current collector 135 may also be affected, which is undesirable.

[0056] When ultrasonic waves are applied in this manner, as shown in FIG. 7, minute cavitations are formed in the NMP solvent 151, similar to the principle of ultrasonic cleaning. These cavitations explode, creating gaps between the electrode layers 133, and the cavitations then penetrate the gaps again and explode, removing the electrode layers 133.

[0057] At this time, in the plate assembly 100 according to the present invention, only the electrode layer 133 formed on one side of the current collector 133 of the double-sided electrode 130 comes into contact with the NMP solvent, while the electrode layer 134 formed on the other side does not come into contact with the NMP solvent, so only the electrode layer 133 on one side is removed, while the electrode layer 134 on the other side remains untouched. This makes it easier to manufacture a single-sided electrode.

[0058] Furthermore, since the worker does not manually remove the electrode layer 133 on one side, there is no deviation due to the worker, and it is possible to remove only the electrode layer 133 on one side.

[0059] Furthermore, since the process uses NMP solvent 151 and ultrasound, there is no surface damage to the current collector 135 of the electrode layer 133 being removed, and the NMP solvent 151 also has the effect of removing impurities, which is advantageous for obtaining a single-sided electrode of excellent quality.

[0060] Meanwhile, although not shown in the drawings, the method for removing one side electrode layer according to one embodiment of the present invention may include a process of drying the one-sided electrode from which the one side electrode layer has been removed after applying the ultrasonic waves, since an NMP solvent is used.

[0061] This allows the NMP solvent to evaporate, ultimately resulting in a reusable single-sided electrode.

[0062] Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content.

[0063] As described above, according to the present invention, when manufacturing a single-sided electrode from a double-sided electrode, deviations due to operators that occur when the process is performed manually in the past can be eliminated, and at the same time, an electrode layer on one side can be removed without damaging the electrode layer on the other side.

[0064] Therefore, the single-sided electrode manufactured in this manner has almost no damage to the surface when used, and therefore, when the single-sided electrode manufactured in this manner is used subsequently, accurate capacitance can be expressed and deviation can be reduced. [Explanation of symbols]

[0065] 10 electrodes 11 Electrode current collector 12 Electrode layer 20 Ultrasonic Horn 100 Plate Assembly 110 Upper Plate 111 Opening 112 Rubber ring 113 Concluding Hole 120 Lower plate 121 Depression 123 Concluding Hole 130 Double-sided electrode Tabs 131 and 132 133, 134 Electrode layer 135 Current collector 140 Fastening bolt 150 aquarium 151 NMP solvent 152 Ultrasonic Horn

Claims

1. A method for removing one electrode layer of a double-sided electrode, comprising: A method for removing a one-sided electrode layer includes interposing a double-sided electrode between an upper plate having an opening communicating with the top and bottom and a lower plate having a recessed portion that is open on one side and closed on the other side, and placing the plate assembly, in which the upper plate and the lower plate are joined together with the double-sided electrode interposed, in an NMP (N-methyl-2-pyrrolidone) water bath and applying ultrasonic waves to the plate assembly.

2. 2. The method of claim 1, wherein the double-sided electrode is disposed between the upper plate and the lower plate, and the opening and the recess are smaller than the area of ​​the double-sided electrode excluding the tabs, so that the opening and the recess completely cover the opening and the recess of the upper plate when the double-sided electrode is disposed between the upper plate and the lower plate.

3. 3. The method for removing one-side electrode layer according to claim 2, wherein the opening and the recessed portion have an area that is 90% to 98% of an area of ​​the double-sided electrode excluding the tab.

4. 2. The method for removing an electrode layer on one side according to claim 1, wherein the inner surface of the upper plate facing the lower plate includes a groove having a shape corresponding to the frame shape of the upper plate, and a rubber ring is attached to the groove.

5. 5. The method of claim 4, wherein the rubber ring presses the entire edge of the double-sided electrode when the double-sided electrode is joined.

6. 2. The method for removing an electrode layer on one surface according to claim 1, wherein the upper plate and the lower plate can be mechanically coupled and disassembled.

7. The method of claim 6 , wherein the upper plate and the lower plate are coupled together by fastening bolts inserted into fastening holes.

8. 2. The method of claim 1, wherein when the plate assembly is placed in an N-methylpyrrolidone (NMP) water bath, no NMP solvent is present between the double-sided electrode and the lower plate.

9. 2. The method for removing a one-side electrode layer according to claim 1, wherein the temperature of the NMP solvent in the NMP water tank is 25 to 60 degrees Celsius.

10. 2. The method for removing an electrode layer on one surface according to claim 1, wherein the NMP bath is provided with two or more ultrasonic horns.

11. 2. The method for removing a one-side electrode layer according to claim 1, wherein ultrasonic waves are applied to the plate assembly while the plate assembly is completely immersed in the NMP solvent.

12. 2. The method for removing a one-side electrode layer according to claim 1, wherein the ultrasonic waves are applied for 5 to 30 minutes.

13. 2. The method for removing a one-side electrode layer according to claim 1, wherein the ultrasonic waves are applied at a frequency of 10 kHz to 500 kHz.

14. The method for removing a one-side electrode layer according to claim 1 , further comprising the step of drying the one-side electrode from which the one-side electrode layer has been removed after applying ultrasonic waves.

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