Processing method of double-sided coated pole piece
By cutting and folding the active substances in the edge area of the pole sheet and covering the conductive parts on the back, the problems of low testing accuracy and assembly difficulty caused by the double-sided coated pole sheet treatment method are solved, and a more efficient electrochemical testing and assembly process is achieved.
Patent Information
- Application Number
- CN202411743327.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-04-04
AI Technical Summary
The treatment method of double-sided coated pole sheet in the prior art results in low testing accuracy and increases the difficulty of subsequent simulated battery assembly.
By cutting the electrode sheet of the electric core, folding and removing the active material in the edge area, the test electrode sheet is formed, and the conductive member is covered on the back to form the test electrode sheet.
It improves the accuracy of electrochemical testing, ensures the integrity and structural stability of the pole sheet body, and reduces the test preparation time and subsequent assembly difficulty.
Smart Images
Figure CN119764308A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for processing a double-sided coated pole piece. Background Art
[0002] With the rapid development of the new energy industry, the demand for lithium-ion batteries has grown rapidly, and the performance requirements for lithium-ion batteries are also constantly increasing. In the design and development process of lithium batteries, in order to solve the problem of battery cell performance failure and optimize battery cell performance, failure analysis is a necessary link in the battery design and development process. The failure analysis process often involves disassembling the battery cell pole pieces and reassembling them into simulated batteries (such as button cells, single-chip soft-pack batteries, etc.) for electrochemical testing (such as cycling, impedance, etc.). Since the pole pieces in lithium battery cells are mostly double-sided coated, when assembling simulated batteries for testing, the active materials on the back side of the pole pieces will also partially participate in the reaction, affecting the accuracy of the test results.
[0003] In the prior art, methods for removing active materials on the back side of double-sided coated electrodes include scraping and rubbing. The scraping method is to use a scraper to scrape off the entire back side of the coated active material. This method often scratches the pole piece and affects the test accuracy; the rubbing method is to select a solvent that can dissolve the active material binder, dissolve the active material on the entire back side of the pole piece, and then wipe it off. This method is less damaging to the pole piece than the scraping method, but the processing time is long and the efficiency is low. In addition, the above two methods of removing the active material on the back side may cause the pole piece to break and affect the accuracy of subsequent tests. Due to the different tensions on both sides, the pole piece will curl spontaneously, causing macroscopic and microscopic damage to the pole piece, reducing the test accuracy and increasing the difficulty of subsequent simulated battery assembly. Summary of the invention
[0004] The main purpose of the present invention is to provide a processing method for double-sided coated pole pieces to solve the problem that the processing method for double-sided coated pole pieces in the prior art leads to low test accuracy and increases the difficulty of subsequent simulated battery assembly.
[0005] In order to achieve the above-mentioned purpose, the present invention provides a processing method for a double-sided coated electrode, comprising: step S20: cutting the battery cell electrode to obtain a to-be-processed electrode, the to-be-processed electrode comprising a electrode body and an electrode ear connected to the electrode body, so that the area of the to-be-processed electrode is A1, wherein, along the thickness direction of the to-be-processed electrode, the to-be-processed electrode has a back side and a front side that are relatively arranged; step S30: folding the edge area of the electrode body to the back side, and exposing the current collector of the edge area on the back side; step S50: covering the back side with a conductive member, and electrically connecting the current collector to the conductive member to form a test electrode.
[0006] Further, step S30 includes: step S31: removing active materials on the back and front sides of the edge region; step S32: folding the edge region from which the active materials are removed to the back side to expose the current collector in the edge region on the back side.
[0007] Furthermore, after step S32, step S30 further includes: step S33 of flattening the edge area of the pole piece body so that the edge area is pressed tightly against the back side.
[0008] Furthermore, before step S50, the method for processing the double-sided coated electrode piece also includes: step S41: cutting the conductor to form a base tape layer; step S42: coating a conductive adhesive on one side of the base tape layer to form a conductive part; step S43: using the conductive adhesive to adhere the base tape layer to the electrode piece to be processed; or, before step S50, the method for processing the double-sided coated electrode piece also includes: cutting the conductive tape to form a conductive part.
[0009] Furthermore, the conductor of the conductive member is copper foil or aluminum foil.
[0010] Furthermore, before step S20, the processing method of the double-sided coated electrode sheet also includes: step S11: determining the area A0 of the test electrode sheet required for the simulated battery, wherein area A1-area A0=area of the edge area; step S12: disassembling the battery cell module to obtain the battery cell electrode sheet.
[0011] Further, after step S32, step S30 also includes: step S34: weighing the mass of the electrode to be processed, and recording the weighed mass as m; step S35: weighing the mass of the electrode foil with an area of A1, and recording the weighed mass as m0; step S36: calculating the mass of the active material of the test electrode as m1, where m1=(m-m0) / 2.
[0012] Furthermore, the processing method of the double-sided coated electrode also includes: step S60: assembling the test electrode into a simulated battery and performing an electrochemical test on the simulated battery; step S70: analyzing the test electrode according to the mass m1 of the active material calculated in step S36 and the electrochemical test results in step S60.
[0013] Furthermore, the battery cell electrode is any one of a fresh electrode that has not been cycled, an electrode after full battery formation, an electrode after constant capacity, and an electrode obtained by disassembling at different charge states after cycling.
[0014] Furthermore, in step S31: the active material on the edge area is removed by using either a scraping method or an wiping method.
[0015] By applying the technical solution of the present invention, the active material on the entire back side needs to be removed only from the edge area by folding the edge area instead of directly removing the active material on the entire back side of the electrode to be processed. On the one hand, physical damage to the entire back side of the electrode to be processed by the scraping and rubbing methods can be avoided, thereby ensuring the integrity and structural stability of the electrode body, thereby improving the accuracy of the electrochemical test and further enabling accurate cell failure analysis. On the other hand, by folding the edge area and completely covering the back side with a conductive part, the active material on the back side of the electrode to be processed can be effectively prevented from participating in the electrochemical reaction, eliminating its influence on the test results, making the test results closer to the real single-sided coated electrode, thereby improving the accuracy of the electrochemical test. On the one hand, the test results are very accurate, and accurate cell failure analysis can be achieved; on the other hand, active materials are only removed from the edge area, and there is no need to process the active materials on the entire back side of the electrode to be processed, and a conductive member is connected to the back side of the electrode to be processed to cover the active materials on the back side of the electrode to be processed, which can improve the processing efficiency and shorten the test preparation time; on the other hand, the folding of the edge area, the exposure of the current collector and the combination of the conductive member can balance the stress on both sides of the electrode to be processed, and effectively prevent the problem of curling after the active materials in the edge area of the electrode to be processed are removed, thereby avoiding macroscopic and microscopic damage to the electrode to be processed, so as to improve the test accuracy, and thus accurate cell failure analysis can be achieved, and the difficulty of subsequent simulated battery assembly can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0017] Figure 1 A process flow chart of an embodiment of a double-sided coated pole piece of the present invention is shown;
[0018] Figure 2 A flow chart of an embodiment of a method for processing a double-sided coated pole piece of the present invention is shown.
[0019] The above drawings include the following reference numerals:
[0020] 1. Pole body; 2. Pole ear; 3. Edge area; 4. Conductive part; 5. Test pole; 6. Current collector; 7. Pole to be processed. DETAILED DESCRIPTION
[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0022] It should be noted that the processing method of the double-sided coated electrode sheet of the embodiment of the present invention is used for lithium batteries.
[0023] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for processing a double-sided coated electrode. The method for processing a double-sided coated electrode comprises: step S20: cutting the electrode of the battery cell to obtain a to-be-processed electrode 7, the to-be-processed electrode 7 comprising a electrode body 1 and an electrode ear 2 connected to the electrode body, so that the area of the to-be-processed electrode 7 is A1, wherein, along the thickness direction of the to-be-processed electrode 7, the to-be-processed electrode 7 has a back side and a front side that are relatively arranged; step S30: folding the edge area 3 of the electrode body 1 to the back side, and exposing the current collector 6 of the edge area 3 on the back side; step S50: covering the conductive member 4 on the back side, and the current collector 6 is electrically connected to the conductive member 4 to form a test electrode 5.
[0024] In the above technical scheme, by folding the edge area 3 instead of directly removing the entire back active material, only the edge area 3 needs to be removed, and there is no need to process the active material on the entire back side of the electrode 7 to be processed. On the one hand, physical damage to the entire back side of the electrode 7 to be processed by the scraping method and the rubbing method can be avoided, thereby ensuring the integrity and structural stability of the electrode body 1, thereby improving the accuracy of the electrochemical test, and further enabling accurate battery cell failure analysis; on the other hand, by folding the edge area 3 and completely covering the back side with the conductive member 4, the active material on the back side of the electrode 7 to be processed can be effectively prevented from participating in the electrochemical reaction, eliminating its influence on the test results, making the test results closer to the real single-sided coated electrode, thereby improving the accuracy of the electrochemical test. , thereby enabling accurate cell failure analysis; on the other hand, only the active material in the edge region 3 is removed, and there is no need to process the active material on the entire back side of the electrode piece 7 to be processed, and the conductive member 4 is connected to the back side of the electrode piece 7 to be processed to cover the active material on the back side of the electrode piece 7 to be processed, which can improve the processing efficiency and shorten the test preparation time; on the other hand, the folding of the edge region 3, the exposure of the current collector 6 and the combination of the conductive member 4 can balance the stress on both sides of the electrode piece 7 to be processed, and effectively prevent the problem of curling caused by the removal of the active material in the edge region 3 of the electrode piece 7 to be processed, thereby avoiding macroscopic and microscopic damage to the electrode piece 7 to be processed, so as to improve the test accuracy, thereby enabling accurate cell failure analysis, and can also reduce the difficulty of subsequent simulated battery assembly.
[0025] Furthermore, since the conductivity of the active material on the back is not as good as that of the current collector, if conductive glue is directly applied to the surface of the active material on the back, the internal resistance of the test electrode 5 will increase, resulting in large errors in the subsequent simulated battery test results. Therefore, in this embodiment, the current collector 6 folded to the edge area 3 on the back is exposed, so that the current collector of the electrode 7 to be processed can directly contact the conductive part 4, thereby increasing the conductivity and reducing the internal resistance of the test electrode 5, thereby improving the accuracy of the simulated battery test results.
[0026] Preferably, in an embodiment of the present invention, the conductive member 4 completely covers the active material on the back side of the pole piece body 1 , and the active material on the front side of the pole piece body 1 is retained.
[0027] It should be noted that, in the embodiment of the present invention, the shape of the conductive member 4 is the same as the shape of the folded pole piece body 1 , and the area of the conductive member 4 is the same as the area of the folded pole piece body 1 .
[0028] It should be noted that, in the embodiment of the present invention, the edge region 3 of the pole piece body 1 refers to Figure 1 The three edges of the pole piece body 1 not connected to the pole ear 2 extend 1 mm to 5 mm toward the center of the pole piece body 1, that is, Figure 1 The edge region 3 of the pole piece body 1 includes a left edge region, a right edge region and a lower edge region, and the width range of the left edge region, the right edge region and the lower edge region is 1mm to 5mm, preferably 2.5mm.
[0029] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, step S30 includes: step S31: removing active materials on the back and front sides of the edge region 3; step S32: folding the edge region 3 from which the active materials are removed to the back side to expose the current collector 6 of the edge region 3 on the back side.
[0030] In the above technical solution, the folding of the edge area 3 effectively balances the stress difference on both sides of the electrode piece 7 to be processed, reduces the spontaneous curling of the electrode piece caused by stress imbalance, thereby reducing the risk of damage to the test electrode piece 5 in the subsequent assembly process, and improving the yield and efficiency of assembly; and the folding of the edge area 3 reinforces the edge of the electrode piece 7 to be processed, increases the overall mechanical strength of the electrode piece 7 to be processed, makes the test electrode piece 5 more stable in the subsequent testing and assembly process, and reduces the possibility of deformation and breakage.
[0031] Furthermore, on the one hand, by removing the active material in the edge area 3, folding the edge area 3 to the back, and then covering the conductive member 4 on the back, it can be ensured that in the electrochemical test, only the active material on one side participates in the reaction, and the interference of the active material on the back side on the test results can be avoided, so as to improve the accuracy and reliability of the test; on the other hand, the current collector 6 exposed on the back side can directly contact the conductive member 4, which can increase the conductivity.
[0032] It should be noted that in an embodiment of the present invention, after the active material in the edge area 3 is completely removed, the edge area 3 needs to be folded to the back along the edge of the electrode body 1, and the current collector 6 in the edge area 3 can be flatly attached to the active material layer on the back to form a closed edge structure to avoid the active material from interfering with the electrochemical reaction from the back edge.
[0033] like Figure 1 and Figure 2 As shown, in the embodiment of the present invention, after step S32, step S30 further includes: step S33 of flattening the edge area 3 of the pole piece body 1 so that the edge area 3 is pressed tightly against the back side.
[0034] In the above technical solution, by flattening the edge area 3, it can be ensured that it fits tightly to the back side, thereby enhancing the overall structural stability of the test electrode 5, and reducing edge delamination, warping and other problems that may occur during subsequent testing or assembly. Flattening the edge area 3 helps to form a flat and closed surface on the back side, which can effectively prevent the electrolyte from penetrating into the non-test area (i.e., the active material on the back side), and avoid the interference of the electrolyte with the test results, thereby ensuring the accuracy and repeatability of the test.
[0035] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, before step S50, the processing method of the double-sided coated electrode piece also includes: step S41: cutting the conductor to form a base tape layer; step S42: coating a conductive adhesive on one side of the base tape layer to form a conductive member 4; step S43: using the conductive adhesive to adhere the base tape layer to the electrode piece 7 to be processed.
[0036] In the above technical scheme, coating the conductive adhesive on the base tape layer (step S42) not only provides a physical connection, but also significantly enhances the electrical conductivity, which helps to reduce the internal resistance on the back of the test electrode 5, thereby improving the electrochemical performance of the simulated battery, for example, improving the charging and discharging efficiency and reducing the internal resistance of the battery; and using the conductive adhesive to stick the base tape layer to the back of the electrode 7 to be processed (step S43) can achieve a more stable sticking effect. Even during the assembly and testing of the simulated battery, the conductive part 4 is not easy to fall off, thereby improving the stability and reliability of the simulated battery.
[0037] It should be noted that, in the embodiment of the present invention, the shape and size of the cut conductor are the same as the shape and size of the electrode body 1 after folding.
[0038] In one embodiment, before step S50, the method for processing the double-sided coated electrode piece further includes: cutting the conductive tape to form the conductive member 4. In this way, the existing conductive tape can be cut, thereby improving the processing efficiency.
[0039] Preferably, in an embodiment of the present invention, the conductor of the conductive member 4 is copper foil or aluminum foil, wherein the positive electrode plate is made of aluminum foil, and the negative electrode plate is made of copper foil.
[0040] like Figure 1 As shown, in an embodiment of the present invention, before step S20, the processing method of the double-sided coated electrode sheet also includes: step S11: determining the area A0 of the test electrode sheet 5 required for the simulated battery, wherein area A1-area A0=area of the edge region 3; step S12: disassembling the battery cell module to obtain the battery cell electrode sheet.
[0041] In the above technical solution, through the pre-operation of steps S11 and S12, the area of the edge region 3 can be accurately planned to ensure that the active material of the electrode body 1 is fully suitable for subsequent simulated battery testing, while avoiding the waste of active material.
[0042] Specifically, in an embodiment of the present invention, when cutting the battery cell electrode to obtain the electrode 7 to be processed, the area A1 is slightly larger than A0, which can ensure the existence of the edge region 3. The retention and subsequent processing of the edge region 3 (such as removal and folding of active materials) can fully utilize the active materials of the electrode, reduce material waste, and improve resource utilization.
[0043] It should be noted that in the embodiment of the present invention, in the process of determining the area of the test electrode 5 required for the simulated battery, its shape and size also need to be determined. When the battery cell is disassembled to obtain the battery cell electrode, the area cut out is slightly larger than the required test electrode 5 to reserve the edge area 3.
[0044] Specifically, in an embodiment of the present invention, after step S32, step S30 also includes: step S34: weighing the mass of the electrode 7 to be processed, and recording the weighed mass as m; step S35: weighing the mass of the electrode foil with an area of A1, and recording the weighed mass as m0; step S36: calculating the mass of the active substance of the test electrode 5 as m1, wherein m1=(m-m0) / 2.
[0045] Through the above-mentioned settings, the mass of the active material on a single side of the test electrode 5 can be calculated, that is, the active material participating in the subsequent electrochemical test can be calculated. The accurate mass data of the active material provides a basis for the subsequent electrochemical test, making the data analysis of the test results more efficient and able to quickly identify the key factors affecting battery performance; and by directly performing mass measurement and active material calculation during the electrode processing process, the tedious calibration and material pretreatment steps before the subsequent test can be avoided, simplifying the entire test preparation process and improving efficiency.
[0046] It should be noted that, in the embodiment of the present invention, the pole sheet foil in the mass of the pole sheet foil with an area of A1 may be an unused pole sheet foil with no active material coated on the surface.
[0047] Specifically, in an embodiment of the present invention, after step S50, the processing method of the double-sided coated electrode plate also includes: step S60: assembling the test electrode plate 5 into a simulated battery and performing an electrochemical test on the simulated battery; step S70: analyzing the test electrode plate 5 according to the mass m1 of the active substance calculated in step S36 and the electrochemical test results in step S60.
[0048] In the above technical scheme, based on the data correlation analysis between the mass m1 of the active material and the electrochemical test results, a quantitative analysis of the causes of cell failure can be achieved, such as evaluating the specific contribution of active material loss to battery capacity decay, or analyzing the impact of uneven distribution of active materials on the increase in battery internal resistance.
[0049] Specifically, in an embodiment of the present invention, the simulated battery can be one of a button battery and a soft-pack battery, and the required electrode shape and size are determined according to the simulated battery structure, and the shape is circular or rectangular.
[0050] Specifically, in an embodiment of the present invention, the battery cell electrode is any one of a fresh electrode that has not been cycled, a electrode after full battery formation, a electrode after constant capacity, and an electrode obtained by disassembling at different states of charge (SOC) after cycling.
[0051] In the above technical scheme, by processing and testing battery cell electrodes in different states, including fresh electrodes, formed electrodes, fixed-capacity electrodes, and cycled electrodes under different states of charge (SOC), the performance changes of the electrodes at various stages of the battery life cycle can be comprehensively evaluated, including capacity attenuation, internal resistance changes, chemical stability of active substances, etc., providing more comprehensive data support for battery performance evaluation.
[0052] Furthermore, by processing and testing the electrodes at different SOC states after cycling, we can conduct in-depth research on the failure mechanism of the battery at different charge states, such as the distribution and structural changes of active substances, the formation and evolution of SEI film (solid electrolyte interface film), the volume expansion and contraction of electrode materials, etc. This will help us understand the reasons for the degradation of battery performance and provide a theoretical basis for extending the battery life.
[0053] Furthermore, testing fresh pole pieces can verify the original performance of the pole piece material, including the conductivity and chemical activity of the active material, the stability of the current collector, etc.; testing pole pieces after cycling can evaluate the stability and degradation of the material under actual use conditions, providing actual performance data for material selection and improvement.
[0054] Preferably, in an embodiment of the present invention, the test electrode 5 includes a positive electrode and a negative electrode.
[0055] Specifically, in the embodiment of the present invention, in step S31: the active material on the edge region 3 is removed by using either a scraping method or an wiping method.
[0056] In the above technical solution, the operation of removing the active material in the edge area 3 is limited to the edge of the electrode, avoiding damage to the active material in the core area of the electrode, thereby maintaining the electrochemical properties of the electrode body 1, which ensures the accuracy of the subsequent assembly into a simulated battery for electrochemical testing and reduces the deviation of the test results; and by removing the active material in the edge area, the influence of edge effects (such as uneven distribution of active materials at the edge or poor contact with the current collector) on the test results can be eliminated, thereby improving the reliability and repeatability of the electrochemical test.
[0057] Furthermore, the removal of active materials in the edge area can simplify the preparation process of the test samples. There is no need to process the active material layer of the entire electrode, which reduces the use of materials and solvents, reduces costs, and also reduces the impact on the environment. Compared with removing the active materials of the entire electrode, removing only the active materials in the edge area 3 can significantly reduce the damage to the electrode, especially avoiding the damage to the current collector and the destruction of the active material layer structure that may be caused by large-area scraping or solvent wiping, thereby improving the integrity and stability of the electrode.
[0058] It should be noted that in the embodiments of the present invention, the method for processing the electrode piece can be applied to processing the electrode pieces of battery cells under different working conditions, and is applicable to assembling button simulation batteries and soft-pack simulation batteries.
[0059] Example 1
[0060] This embodiment provides a method for processing a double-sided coated electrode of a lithium battery. Figure 1 As shown, the following steps are included:
[0061] (1) Determine a square single-piece soft-pack simulated battery with a side length of 4 cm for assembling the active material layer (pole piece body 1), and cut out a square pole piece with a side length of 4.5 cm for the active material layer (pole piece body 1) from the negative pole piece disassembled from the battery cell;
[0062] (2) Using a scraper to remove the active materials on both sides of the front and back sides of the edge area of the electrode obtained by cutting in step (1), and folding the edge area of the electrode after removing the active materials to the back side, flattening the electrode, and weighing the mass of the electrode to be 669 mg;
[0063] (3) Cut a conductive tape with a copper foil substrate into a square with a side length of 4 cm, which is the same shape and size as the electrode required for the simulated battery in step (1);
[0064] (4) Paste the conductive tape obtained in step (3) on the back of the electrode sheet treated in step (2) to completely cover the active material on the back, that is, the double-sided coated electrode sheet with a side length of 4.5 cm square has been processed into a single-sided coated electrode sheet with a side length of 4 cm square;
[0065] (5) The weight of a square copper foil with a side length of 4.5 cm was weighed to be 105 mg, and the weight of the active material in the treated single-sided coated electrode was calculated to be 282 mg;
[0066] (6) Assemble the electrode pieces processed in step (4) into a 4 cm square single-piece soft-pack simulated battery as described in step (1) for subsequent testing.
[0067] (7) The single-piece soft-pack battery assembled in step (6) was subjected to a charge and discharge test at a rate of 0.05C.
[0068] Comparative Example 1
[0069] This comparative example 1 provides a method for processing a double-sided coated electrode sheet of a lithium battery, and the processing steps are: select the same battery cell as in Example 1 to disassemble the negative electrode sheet, wipe the active material on the back of the electrode sheet with a dust-free cloth soaked in deionized water, dry the electrode sheet, cut a square electrode sheet with a side length of 4 cm, and assemble it into a single-chip soft-pack simulated battery. The assembled single-chip soft-pack battery is charged and discharged at a rate of 0.05C.
[0070] Comparative Example 2
[0071] This comparative example 2 provides a method for processing a double-sided coated electrode sheet of a lithium battery, and the processing steps are: select the same battery cell as in Example 1, disassemble the negative electrode sheet, cut a square electrode sheet with a side length of 4 cm, paste a square copper foil conductive adhesive with a side length of 4 cm on the back of the electrode sheet to completely cover the back, and assemble the processed electrode sheets into a single-piece soft-pack simulated battery. The assembled single-piece soft-pack battery is charged and discharged at a rate of 0.05C.
[0072] The discharge capacity of the electrode sheet treated in Example 1 at a rate of 0.05C was compared with the electrode sheets of Comparative Examples 1 and 2.
[0073] Table 1
[0074] First discharge capacity (mAh) Example 1 5.69 Comparative Example 1 5.74 Comparative Example 2 2.12
[0075] As shown in Table 1, the error between the capacity measurement of the double-sided coated electrode after the treatment method of Example 1 and the capacity measurement of the electrode after the conventional erasing method of Comparative Example 1 is small, indicating that the present invention can avoid the influence of the active material on the back of the electrode on the capacity test without removing the active material on the back of the electrode. The electrode capacity result of Comparative Example 2 deviates greatly from the results of Example 1 and Comparative Example 1, indicating that the electrode after the electrode edge is not processed by the scraping and folding step will increase the electrode resistance, resulting in large polarization and inability to charge and discharge normally, and large test errors.
[0076] In summary, the method for processing a double-sided coated electrode according to an embodiment of the present invention has the following beneficial effects:
[0077] The electrode processing method of the present invention can achieve the same test results as single-sided coating, with small errors;
[0078] The electrode processing method of the present invention has simple steps and is highly efficient;
[0079] The electrode processing method of the present invention will not cause damage to the electrode surface during the electrode processing process;
[0080] The pole piece processing method of the present invention can process pole pieces under different working conditions and can be used to analyze the pole piece performance under different working conditions;
[0081] The pole piece processing method of the present invention can be applied to the pole piece processing required by simulated batteries with different structures, such as button batteries and soft-pack batteries.
[0082] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: by folding the edge area instead of directly removing the entire back active material, only the edge area needs to be removed, and there is no need to process the active material on the entire back of the electrode to be processed. On the one hand, physical damage to the entire back of the electrode to be processed by the scraping and rubbing methods can be avoided, thereby ensuring the integrity and structural stability of the electrode body, thereby improving the accuracy of the electrochemical test, and further enabling accurate cell failure analysis; on the other hand, by folding the edge area and completely covering the back with a conductive member, the active material on the back of the electrode to be processed can be effectively prevented from participating in the electrochemical reaction, eliminating its influence on the test results, so that the test results are closer to the real single-sided coated electrode. Thereby improving the accuracy of electrochemical testing, and thus enabling accurate cell failure analysis; on the other hand, only the edge area is subjected to removal of active material, and there is no need to process the active material on the entire back side of the electrode to be processed, and a conductive member is connected to the back side of the electrode to be processed to cover the active material on the back side of the electrode to be processed, which can improve processing efficiency and shorten test preparation time; on the other hand, the folding of the edge area, the exposure of the current collector and the combination of the conductive member can balance the stress on both sides of the electrode to be processed, and effectively prevent the problem of curling caused by the removal of active material from the edge area of the electrode to be processed, thereby avoiding macroscopic and microscopic damage to the electrode to be processed, so as to improve test accuracy, and thus enabling accurate cell failure analysis, and can also reduce the difficulty of subsequent simulated battery assembly.
[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for processing a double-sided coated electrode, characterized in that: include: Step S20: cutting the electrode sheet of the battery cell to obtain an electrode sheet (7) to be processed, wherein the electrode sheet (7) to be processed comprises an electrode sheet body (1) and an electrode ear (2) connected to the electrode sheet body, so that the area of the electrode sheet (7) to be processed is A1, wherein along the thickness direction of the electrode sheet (7) to be processed, the electrode sheet (7) to be processed has a back side and a front side that are arranged opposite to each other; Step S30: folding the edge region (3) of the pole piece body (1) to the back side, and exposing the current collector (6) of the edge region (3) on the back side; Step S50: Covering the back side with a conductive member (4), and electrically connecting the current collector (6) to the conductive member (4) to form a test electrode (5).
2. The method for processing a double-sided coated electrode according to claim 1, characterized in that: The step S30 comprises: Step S31: removing the active material in the edge region (3) on the back side and the front side; Step S32: folding the edge region (3) from which the active material has been removed to the back side, so as to expose the current collector (6) of the edge region (3) on the back side.
3. The method for processing a double-sided coated electrode according to claim 2, characterized in that: After step S32, step S30 further includes: step S33 of flattening the edge region (3) of the pole piece body (1) so that the edge region (3) is pressed tightly against the back side.
4. The method for processing a double-sided coated electrode according to claim 1, characterized in that: Before step S50, the method for processing the double-sided coated electrode piece further includes: Step S41: cutting the conductor to form a base tape layer; Step S42: coating a conductive adhesive on one side of the base tape layer to form the conductive member (4); Step S43: using the conductive adhesive to adhere the base tape layer to the electrode to be processed (7); or, Before the step S50, the method for processing the double-sided coated electrode sheet further comprises: cutting the conductive tape to form the conductive member (4).
5. The method for processing a double-sided coated electrode according to claim 4, characterized in that: The conductor of the conductive member (4) is copper foil or aluminum foil.
6. The method for processing a double-sided coated electrode according to any one of claims 1 to 5, characterized in that: Before step S20, the method for processing the double-sided coated electrode piece further includes: Step S11: determining the area A0 of the test electrode (5) required for the simulated battery, wherein the area A1-the area A0=the area of the edge region (3); Step S12: disassemble the battery cell module to obtain the battery cell electrode piece.
7. The method for processing a double-sided coated electrode according to any one of claims 2 to 5, characterized in that: After step S32, step S30 further includes: Step S34: weighing the mass of the electrode (7) to be processed, and recording the weighed mass as m; Step S35: weighing the mass of the electrode foil with an area of A1, and recording the weighed mass as m0; Step S36: Calculate the mass of the active material of the test electrode (5) as m1, where m1 = (m-m0) / 2.
8. The method for processing a double-sided coated electrode according to claim 7, characterized in that: After step S50, the method for processing the double-sided coated electrode piece further includes: Step S60: assembling the test electrode (5) into a simulated battery, and performing an electrochemical test on the simulated battery; Step S70: Analyze the test electrode (5) according to the mass m1 of the active material calculated in step S36 and the electrochemical test result in step S60.
9. The method for processing a double-sided coated electrode according to any one of claims 1 to 5, characterized in that: The battery cell electrode is any one of a fresh electrode that has not been cycled, an electrode after full battery formation, an electrode after constant capacity, and an electrode obtained by disassembling at different charge states after cycling.
10. The method for processing a double-sided coated electrode according to any one of claims 2 to 5, characterized in that: In step S31: the active material on the edge area (3) is removed by using either a scraping method or an wiping method.