Positive electrode sheet, method for producing electrode sheet, and battery

Abstract

The application provides a positive electrode sheet, an electrode sheet production method and a battery. The positive electrode sheet comprises an insulating coating, a base layer and an active layer. The insulating coating comprises a lower insulating coating and an upper insulating coating. The base layer is provided with a pre-coating area. The lower insulating coating is coated on the pre-coating area. The upper insulating coating is coated on the lower insulating coating. Each insulating coating comprises a binder. The weight proportion of the binder in the upper insulating coating is less than that in the lower insulating coating relative to the base layer. The active layer is coated on the base layer. The position of the active layer opposite to the insulating coating is provided with a containing groove formed by the insulating coating. The containing groove is used for corresponding to a negative electrode tab. The positive electrode sheet structure is beneficial to forming protection for the base layer when the containing groove is arranged, and ensures the performance of the positive electrode sheet. The application further provides an electrode sheet production method and a battery. The electrode sheet production method is used for producing the positive electrode sheet. The battery comprises the positive electrode sheet, and is beneficial to improving the capacity density of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a positive electrode, an electrode manufacturing method, and a battery. Background Technology

[0002] In battery manufacturing technology, the foil layer of the electrode is pre-coated with ceramic, and grooves are formed by cleaning the pre-coated ceramic areas. The pre-coated ceramic protects the foil material during cleaning, and the grooves accommodate the tab protective adhesive to increase the battery's capacity density. However, the degree of cleaning when creating these grooves on the electrode is difficult to control. Incomplete cleaning leaves residual active material and / or a thick ceramic coating on the electrode surface, which is not conducive to accommodating the tab protective adhesive. Over-cleaning can lead to foil leakage or puncture, affecting the electrode's performance. Summary of the Invention

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes a positive electrode sheet that is easy to clean to form a receiving groove, which is beneficial to ensuring the performance of the electrode sheet.

[0004] This application also proposes a method for producing electrode sheets;

[0005] This application also proposes a battery having the aforementioned electrodes.

[0006] According to a first aspect embodiment of this application, the positive electrode sheet includes an insulating coating, a base layer, and an active layer. The insulating coating includes a lower insulating coating and an upper insulating coating. The base layer has a pre-coating area. The lower insulating coating is coated on the pre-coating area, and the upper insulating coating is coated on the lower insulating coating. The material of each insulating coating includes an adhesive, and the weight percentage of the adhesive in the upper insulating coating is less than the weight percentage of the adhesive in the lower insulating coating relative to the base layer. The active layer is coated on the base layer, and a receiving groove is formed on the active layer opposite to the insulating coating. The receiving groove is used to correspond to the negative electrode tab.

[0007] The positive electrode sheet according to the first aspect of this application has at least the following beneficial effects: the weight ratio of the binder in the upper insulating coating is less than that in the lower insulating coating, thus the upper insulating coating has poorer adhesion and is easier to remove. This improves the problem of residual active material and / or a thick insulating coating after the positive electrode sheet has been provided with a receiving groove, ensuring the depth of the receiving groove and facilitating the accommodating groove to accommodate the protective adhesive. Compared with the upper insulating coating, the lower insulating coating is more difficult to remove, which can prevent excessive cleaning from causing electrode foil leakage or electrode breakdown, thus protecting the base layer of the positive electrode sheet and ensuring its normal use.

[0008] According to the positive electrode sheet of this application embodiment, the active layer is coated on the base layer, and the receiving groove is formed on the active layer opposite to the upper insulating coating layer.

[0009] According to the positive electrode sheet of this application embodiment, the active layer is coated on the base layer, and the receiving groove is formed on the active layer opposite to the lower insulating coating layer.

[0010] According to the embodiments of this application, the thickness 'a' of the lower insulating coating of the positive electrode sheet ranges from 6μm ≤ a ≤ 12μm.

[0011] According to the embodiments of this application, the thickness b of the upper insulating coating of the positive electrode sheet is in the range of 0 μm < b ≤ 10 μm.

[0012] According to the electrode production method of the present application embodiment, the steps include: setting an insulating coating: selecting a pre-coated area on a substrate and coating at least two layers of insulating coating on the pre-coated area, wherein the material of each insulating coating includes an adhesive, and the weight percentage of the adhesive in the outermost insulating coating is less than the weight percentage of the adhesive in the other insulating coatings relative to the substrate.

[0013] Apply an active layer: Coat the active layer on the base layer, covering the base layer and the insulating coating;

[0014] To create a receiving groove: remove the active layer covering the outside of the insulating coating to expose the insulating coating and form a receiving groove on the active layer; or, remove the active layer covering the outside of the insulating coating and part of the insulating coating to form a receiving groove.

[0015] The electrode production method according to the embodiments of this application has at least the following beneficial effects: the method can be used to produce the positive electrode in any of the above embodiments. During the production process, by setting at least two insulating coatings containing different weights of adhesive, the base layer can be protected when setting the receiving groove, thus ensuring the integrity of the positive electrode.

[0016] According to the electrode manufacturing method of this application embodiment, the method for setting the insulating coating includes:

[0017] Apply a lower insulating coating to the pre-coated area, so that the lower insulating coating adheres to the pre-coated area;

[0018] An upper insulating coating is applied over a lower insulating coating to bond the upper insulating coating to the lower insulating coating. Both the lower and upper insulating coatings contain adhesives, and the weight percentage of the adhesive in the lower insulating coating is greater than that in the upper insulating coating.

[0019] According to the electrode production method of the present application embodiment, the materials of the lower insulating coating and the upper insulating coating also include ceramic particles. The weight percentage of the binder in the lower insulating coating is 1% to 75%, and the weight percentage of the binder in the upper insulating coating is 1% to 55%.

[0020] According to the electrode production method of this application embodiment, the method of setting the receiving groove includes: removing the active layer covering the upper insulating coating to expose the upper insulating coating;

[0021] Remove part or all of the upper insulating coating that covers the lower insulating coating to form a receiving groove on the active layer.

[0022] The battery according to an embodiment of this application includes a first electrode and a second electrode. The first electrode is the positive electrode as described in any of the above embodiments, and the second electrode is connected to a tab. A receiving groove on the first electrode is provided corresponding to the tab of the second electrode.

[0023] The battery according to the embodiments of this application has at least the following beneficial effects: the second electrode is connected to the tab, the tab is covered with tab protective adhesive, the receiving groove can accommodate the tab protective adhesive, and the insulating coating can isolate the tab protective adhesive from contact with the base layer of the first electrode, further preventing the tab from being connected to the first electrode and the second electrode at the same time and causing a short circuit, which is beneficial to improving the safety of the battery.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0025] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic flowchart of the electrode production method according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the structure of the electrode sheet before the receiving groove is provided in the embodiment of this application;

[0028] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle;

[0029] Figure 4 This is a schematic diagram of the structure of the electrode sheet after the receiving groove is provided in the embodiment of this application;

[0030] Figure 5 for Figure 4 A magnified view of a portion of point B in the middle;

[0031] Figure 6 Another structural schematic diagram of the electrode sheet after the receiving groove is provided in the embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the structure of the electrode sheet comprising three insulating coating layers according to an embodiment of this application;

[0033] Figure 8This is a schematic diagram of the structure of the electrode sheet comprising four insulating coating layers according to an embodiment of this application;

[0034] Figure 9 This is a schematic diagram of the structure of adjacent electrodes in the battery of an embodiment of this application;

[0035] Figure 10 for Figure 9 A magnified view of a portion of point C.

[0036] Attached diagram labels: Base layer 100, Pre-coated area 110;

[0037] Insulating coating 200, lower insulating coating 210, upper insulating coating 220, third insulating coating 230, fourth insulating coating 240;

[0038] Active layer 300, receiving tank 310;

[0039] Electrode 400, first electrode 410, second electrode 420, tab 430, tab protective adhesive 440. Detailed Implementation

[0040] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0041] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0043] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0044] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] The embodiments of this application are described below with reference to the accompanying drawings:

[0046] refer to Figure 4 and Figure 5 An electrode sheet according to a first aspect of this application includes an insulating coating 200, a base layer 100, and an active layer 300. The insulating coating 200 includes a lower insulating coating 210 and an upper insulating coating 220. A pre-coating area 110 is provided on the base layer 100. The lower insulating coating 210 is coated and bonded to the pre-coating area 110, and the upper insulating coating 220 is coated and covers the lower insulating coating 210. The material of each insulating coating 200 includes an adhesive, and the weight ratio of the adhesive in the upper insulating coating 220 is less than that in the lower insulating coating 210 relative to the base layer 100. The upper insulating coating 220 is located on the outermost side of the base layer 100. The active layer 300 is coated on the base layer 100. A receiving groove 310 is formed on the active layer 300 opposite to the insulating coating 200. The receiving groove 310 is correspondingly provided with the negative electrode tab and is used to receive the tab protective adhesive. It should be noted that the thickness of the active layer 300 should be greater than the combined thickness of the lower insulating coating 210 and the upper insulating coating 220, so that the active layer 300 and the insulating coating 200 form a receiving groove 310, which is used to accommodate the tab protective adhesive. Therefore, when the receiving groove 310 is provided, the electrode sheet can provide better protection for the base layer 100, which is beneficial to improving the safety of the electrode sheet during use and extending the battery's lifespan.

[0047] refer to Figure 4 and Figure 5 In some embodiments, a receiving groove 310 is formed on the active layer 300 opposite to the upper insulating coating 220. This structure allows a portion of the upper insulating coating 220 to be retained, reducing production difficulty. Retaining a portion of the upper insulating coating 220 can provide better protection for the base layer 100, preventing damage to the base layer 100 during production, and is beneficial to fully ensuring the performance of the positive electrode sheet.

[0048] refer to Figure 6In other embodiments, a receiving groove 310 is formed on the active layer 300 opposite to the lower insulating coating 210. This structure completely removes the upper insulating coating 220 on the positive electrode sheet, increasing the receiving space of the receiving groove 310 to better accommodate the tab protective adhesive, which helps to increase the capacity density of the battery.

[0049] refer to Figure 2 , Figure 3 and Figure 6 Specifically, the positive electrode includes a base layer 100, an insulating coating 200, and an active layer 300. The base layer 100 has a pre-coating area 110, the insulating coating 200 is coated on the pre-coating area 110, and the active layer 300 is coated on the base layer 100. A receiving groove 310 is formed on the active layer 300 opposite to the insulating coating 200, and the receiving groove 310 is used to receive the tab protective adhesive. It should be understood that the electrode in this embodiment is an electrode with the receiving groove 310 provided. Its insulating coating 200 may only include the lower insulating coating 210. Other insulating coatings 200 are removed during the electrode production process. Retaining the lower insulating coating 210 maximizes the receiving space of the receiving groove 310, which is beneficial for the receiving groove 310 to accommodate the tab protective adhesive. At the same time, the lower insulating coating 210 also protects the base layer 100, preventing damage to the base layer 100 during electrode production and ensuring the production quality of the electrode.

[0050] It should be noted that the lower insulating coating 210 in this embodiment is allowed to wear partially, but the thickness 'a' of the lower insulating coating 210 should be within the range of 6μm≤a≤12μm. Limiting the minimum thickness of the lower insulating coating 210 is beneficial to ensuring the protection of the base layer 100, and limiting the maximum thickness of the lower insulating coating 210 is beneficial to providing sufficient space for the receiving groove 310 to accommodate the tab protective adhesive.

[0051] refer to Figures 3 to 5 In some embodiments, the lower insulating coating 210 has a certain thickness 'a', where 'a' ranges from 6μm to 12μm. The thickness of the upper insulating coating 220 can be adjusted according to actual needs. The thickness of the lower insulating coating 210 should not be too large or too small. If the thickness of the lower insulating coating 210 is too large, it will occupy more space in the receiving groove 310, which is not conducive to the receiving groove 310's containment of the tab protective adhesive. If the thickness of the lower insulating coating 210 is too small, the lower insulating coating 210 may not provide sufficient protection for the base layer 100 of the electrode when the upper insulating coating 220 is removed. Setting the thickness 'a' of the lower insulating coating 210 between 6μm and 12μm can provide good protection for the base layer 100 without occupying too much space in the receiving groove 310. This is beneficial for the adhesion of adjacent electrodes in the battery, thereby improving the battery's capacity density.

[0052] refer to Figures 3 to 5 In some embodiments, the upper insulating coating 220 is located on the outermost side of the base layer 100, and the thickness b of the upper insulating coating 220 is in the range of 0 μm < b ≤ 10 μm. It should be understood that when the receiving groove 310 is set, the upper insulating coating 220 is gradually removed, and its thickness b continuously decreases. Before and after the removal of the upper insulating coating 220, its thickness b is always within the above-mentioned range. The upper insulating coating 220 provides sufficient removal space for the receiving groove 310. After removal, the upper insulating coating 220 is allowed to remain partially. Compared with setting a single coating, a lower insulating coating 210 is provided between the base layer 100 and the upper insulating coating 220. The upper insulating coating 220 can provide sufficient removal thickness, and the lower insulating coating 210 can protect the base layer 100 of the electrode sheet during removal and prevent the electrode sheet from being damaged. It should be understood that the sum of the thickness of the lower insulating coating 210 and the upper insulating coating 220 should be less than the thickness of the active layer 300 located outside the pre-coated area 110. If the thickness b of the upper insulating coating 220 is too large, the thickness a of the lower insulating coating 200 will be correspondingly smaller, resulting in insufficient protection of the base layer 100 of the electrode sheet and damage to the foil of the base layer 100. Therefore, limiting the thickness b of the upper insulating coating 220 is beneficial to protect the base layer 100 and prevent damage to the foil of the base layer 100.

[0053] refer to Figures 1 to 4 According to the electrode manufacturing method of this application embodiment, the manufacturing steps include:

[0054] Setting up an insulating coating 200: Select a pre-coated area 110 on the base layer 100, and apply at least two layers of insulating coating 200 on the pre-coated area 110. The material of each insulating coating 200 includes an adhesive, and the weight percentage of the adhesive in the outermost insulating coating 200 relative to the base layer 100 is less than the weight percentage of the adhesive in the other insulating coatings 200.

[0055] Setting active layer 300: Active layer 300 is coated on base layer 100, and active layer 300 covers base layer 100 and insulating coating 200;

[0056] The receiving groove 310 is formed by removing the active layer 300 covering the outside of the insulating coating 200, exposing the insulating coating 200, and forming the receiving groove 310 on the active layer 300; or by removing the active layer 300 covering the outside of the insulating coating 200 and part of the insulating coating 200 to form the receiving groove 310.

[0057] It should be noted that the insulating coating 200 includes an adhesive. Compared to the insulating coatings 200 in other locations, the outermost insulating coating 200 on the base layer 100 has the smallest weight percentage of adhesive. The weight percentage of adhesive in all other insulating coatings 200 is greater than that in the outermost insulating coating 200 on the base layer 100. Except for the outermost insulating coating 200 on the base layer 100, the weight percentage of adhesive in the other insulating coatings 200 can be the same or different. The outermost insulating coating 200 of the base layer 100 has a certain thickness. When removing it, since the adhesive weight ratio of the outermost insulating coating 200 of the base layer 100 is the smallest, its adhesion is worse than that of the other insulating coatings 200, making it easier to remove. This makes it easier to form a receiving groove 310 on the active layer 300. Furthermore, by changing the coating thickness of the outermost insulating coating 200 of the base layer 100, the depth of the receiving groove 310 can be changed without changing the removal force. The receiving groove 310 is beneficial for accommodating the tab protective adhesive and improving the capacity density of the battery.

[0058] In addition, except for the outermost insulating coating 200 located on the base layer 100, the adhesive weight of the insulating coating 200 in other locations is relatively large, and its adhesion is good. Under the condition of not changing the removal force, the insulating coating 200 with good adhesion is not easy to remove, which can prevent excessive removal from causing electrode foil leakage or breakdown and other adverse conditions, which is beneficial to ensuring the performance of the electrode.

[0059] For example, refer to Figures 2 to 5 First, a pre-coating area 110 is selected on the base layer 100 according to the size of the tab protective adhesive. The base layer 100 is a current collector and can be made of copper foil or aluminum foil. A lower insulating coating 210 and an upper insulating coating 220 are sequentially coated on the selected pre-coating area 110. The lower insulating coating 210 is coated on the pre-coating area 110 of the base layer 100, and the upper insulating coating 220 is coated and covers the lower insulating coating 210. Both the lower insulating coating 210 and the upper insulating coating 220 contain adhesive. The upper insulating coating 220 is located on the outermost side of the base layer 100 relative to the base layer 100. The weight ratio of the adhesive in the upper insulating coating 220 is less than that in the lower insulating coating 210. After coating the upper insulating coating 220, an active layer 300 is coated on the base layer 100. The active layer 300 covers the base layer 100 and the upper insulating coating 220.

[0060] When setting the receiving groove 310, the pre-coated area 110 can be cleaned and removed using laser cleaning equipment or other means. First, the active layer 300 covering the upper insulating coating 220 is removed, exposing the upper insulating coating 220. The active layer 300 and the upper insulating coating 220 together form the receiving groove 310. This receiving groove 310 is used to accommodate the tab protective adhesive. In addition, at least partially or completely removing the upper insulating coating 220 makes the receiving groove 310 deeper. Compared with the adhesive weight ratio in the lower insulating coating 210, the adhesive weight ratio in the upper insulating coating 220 is smaller, making it easier to remove and reducing the thickness of the insulating coating to better accommodate the tab protective adhesive. At the same time, the lower insulating coating 210 is more difficult to remove, which helps protect the base layer 100 of the electrode and ensures the performance of the electrode.

[0061] In other embodiments, reference is made to Figure 5 and Figure 7 The insulating coating 200 includes a lower insulating coating 210, an upper insulating coating 220, and a third insulating coating 230. The lower insulating coating 210 is applied to the pre-coated area 110 of the base layer 100. The upper insulating coating 220 is applied to and covers the lower insulating coating 210. The third insulating coating 230 is applied to and covers the upper insulating coating 220. After the third insulating coating 230 is applied, an active layer 300 is applied to the base layer 100. The active layer 300 covers the base layer 100 and the third insulating coating 230. The third insulating coating 230 is located on the outermost side of the base layer 100. Compared with the lower insulating coating 210 and the upper insulating coating 220, the third insulating coating 230 has a smaller weight ratio of adhesive, poorer adhesion, and is easier to remove. This helps to reduce the thickness of the insulating coating 200 and better contain the tab protective adhesive. Meanwhile, compared to the lower insulating coating 210, the upper insulating coating 220 has a smaller weight ratio of binder. Therefore, the binder weight ratio of the third insulating coating 230, the upper insulating coating 220, and the lower insulating coating 210 increases sequentially, making removal increasingly difficult. When setting the receiving groove 310, at least a portion of the third insulating coating 230 must be removed to form the receiving groove 310. This facilitates control of the removal equipment's force, improving the problem of insufficient space in the receiving groove 310 due to insufficient removal of the insulating coating 200, or damage to the electrode due to over-removal, thus improving the quality of the electrode.

[0062] It should be noted that the weight ratio of the binder in the lower insulating coating 210 and the upper insulating coating 220 can also be the same. The lower insulating coating 210 and the upper insulating coating 220 can be made of different materials. For example, the lower insulating coating 210 can contain alumina, and the upper insulating coating 220 can contain silicon dioxide. Alumina has good chemical stability, while silicon dioxide has high hardness and good wear resistance. Thus, the lower insulating coating 210 and the upper insulating coating 220 can provide different protective layers for the base layer 100, which is beneficial to improving the production quality of the electrode sheet.

[0063] refer to Figure 5 and Figure 8 In some embodiments, the insulating coating 200 includes a lower insulating coating 210, an upper insulating coating 220, a third insulating coating 230, and a fourth insulating coating 240. The lower insulating coating 210 is applied to the pre-coated area 110 of the base layer 100. The upper insulating coating 220 is applied to and covers the lower insulating coating 210. The third insulating coating 230 is applied to and covers the upper insulating coating 220. The fourth insulating coating 240 is applied to and covers the third insulating coating 230. The fourth insulating coating 240 is located on the outermost side of the base layer 100. Compared to the other three insulating coatings, the weight of the adhesive in the fourth insulating coating 240 accounts for a larger proportion. The adhesive layer is relatively small and easy to remove. After removing the active layer 300 covering the fourth insulating coating 240, the removal equipment can continue to remove the fourth insulating coating 240. The adhesive weight ratio of the fourth insulating coating 240, the third insulating coating 230, the upper insulating coating 220, and the lower insulating coating 210 increases sequentially, and the removal difficulty increases sequentially. The removal equipment can gradually increase the force to remove the fourth insulating coating 240, the third insulating coating 230, the upper insulating coating 220, and the lower insulating coating 210 in sequence. When setting the receiving groove 310, at least part of the fourth insulating coating 240 is removed, thereby forming the receiving groove 310. Therefore, it is easier to control the removal force of the removal equipment, better set the receiving groove 310, and is beneficial to the protection of the electrode sheet.

[0064] It should be noted that the weight percentage of the binder in the lower insulating coating 210, upper insulating coating 220, and third insulating coating 230 can also be the same. The lower insulating coating 210, upper insulating coating 220, and third insulating coating 230 can contain different materials. For example, the lower insulating coating 210 can contain alumina, the upper insulating coating 220 can contain silicon dioxide, and the third insulating coating 230 can contain magnesium oxide. Alumina has good chemical stability, silicon dioxide has high hardness and good wear resistance, and magnesium oxide has high fire resistance. Thus, the lower insulating coating 210, upper insulating coating 220, and third insulating coating 230 can provide different protective layers for the base layer 100, preventing damage to the base layer 100 of the electrode and improving the safety of the electrode.

[0065] It should be understood that the insulating coating 200 can be divided into at least two layers as needed. The outermost insulating coating 200 of the base layer 100 has the smallest weight of adhesive, and its adhesion is worse than that of the insulating coating 200 in other locations. It is easier to remove, which makes it easier to control the degree of removal of the insulating coating 200. While setting the receiving groove 310 on the electrode, it can protect the base layer 100 of the electrode and ensure the use of the electrode.

[0066] refer to Figures 2 to 4 In some embodiments, when setting the insulating coating 200, a pre-coating area 110 is first selected according to the size of the tab protective adhesive, and a lower insulating coating 210 is applied to the pre-coating area 110 to bond the lower insulating coating 210 to the pre-coating area 110. Then, an upper insulating coating 220 is applied over the lower insulating coating 210, covering and bonding the upper insulating coating 220 to the lower insulating coating 210. Both the lower insulating coating 210 and the upper insulating coating 220 are made of adhesive. The weight ratio of the adhesive in layer 10 is greater than that of the adhesive in the upper insulating coating 220. As a result, the adhesion of the upper insulating coating 220 is less than that of the lower insulating coating 210. The upper insulating coating 220 is easier to remove than the lower insulating coating 210. Under the condition of constant removal force, the active layer 300 covering the upper insulating coating 220 can be removed first, and then the upper insulating coating 220 can be gradually removed, thereby forming a receiving groove 310 between the active layer 300 and the upper insulating coating 220.

[0067] Specifically, because the weight proportion of binder in the lower insulating coating 210 and the upper insulating coating 220 is different, the removal force required for the lower insulating coating 210 and the upper insulating coating 220 is different. Compared with the lower insulating coating 210, the weight proportion of binder in the upper insulating coating 220 is lower, and the removal force required for the upper insulating coating 220 is different. Therefore, under the condition that the removal force required to remove the upper insulating coating 220 is met, but the removal force required to remove the lower insulating coating 210 is not met, the lower insulating coating 210 cannot be removed no matter how the position of the removal equipment is adjusted. Compared with setting a single insulating coating 200, this solution can control the removal degree by setting the removal force, such as adjusting the power of the laser cleaning equipment, without having to adjust the position of the removal equipment to remove the insulating coating 200. This makes it easier to control the removal degree of the insulating coating 200 in the pre-coated area 110, avoids the electrode being broken down during removal, and helps to increase the quality of the electrode.

[0068] It should be noted that the adhesive can be one or more of the following: polyvinylidene fluoride, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoroethylene, or styrene-butadiene rubber.

[0069] refer to Figures 2 to 5 In some embodiments, the materials of the lower insulating coating 210 and the upper insulating coating 220 include ceramic particles, which may be one or more combinations of alumina, silicon dioxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium dioxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, or barium sulfate.

[0070] Furthermore, the binder in the lower insulating coating 210 comprises 1% to 75% by weight, while the binder in the upper insulating coating 220 comprises 1% to 55% by weight. It should be noted that the upper insulating coating 220 is located on the outermost side of the base layer 100, and the binder weight percentage in the upper insulating coating 220 is less than that in the lower insulating coating 210. Therefore, the adhesive strength of the upper insulating coating 220 is less than that of the lower insulating coating 210, making the upper insulating coating 220 easier to remove than the lower insulating coating 210. The lower insulating coating 210 is used to protect the electrode base layer 100, while the upper insulating coating 220 is used for removal, thereby forming the receiving groove 310. During the removal process to form the receiving groove 310, partial residue of the upper insulating coating 220 is permissible, while partial removal of the lower insulating coating 210 is permissible. Therefore, when setting the receiving groove 310, it can ensure that the receiving groove 310 has good capacity to accommodate the tab protective adhesive, and can also protect the base layer 100 of the electrode sheet, avoiding damage to the base layer 100 when the insulating coating is removed.

[0071] refer to Figures 2 to 5 In some embodiments, a lower insulating coating 210 is coated and bonded to a pre-coated area 110, an upper insulating coating 220 is coated on the lower insulating coating 210, and an active layer 300 is coated on the upper insulating coating 220. When the receiving groove 310 is set, the active layer 300 covering the upper insulating coating 220 is removed to expose the upper insulating coating 220. Then, the upper insulating coating 220 covering the lower insulating coating 210 is removed. The upper insulating coating 220 can be partially or completely removed. It should be understood that the greater the degree of removal, the greater the depth of the receiving groove 310, and correspondingly, the less protection the base layer 100 provides. Therefore, when removing the upper insulating coating 220, the removal thickness of the upper insulating coating 220 by the removal equipment can be adjusted according to the actual situation.

[0072] refer to Figures 2 to 5In some embodiments, a lower insulating coating 210 is coated and bonded to a pre-coated area 110, an upper insulating coating 220 is coated on the lower insulating coating 210, and an active layer 300 is coated on the upper insulating coating 220. When setting the receiving groove 310, the active layer 300 covering the upper insulating coating 220 is removed to expose the upper insulating coating 220. The upper insulating coating 220 is partially removed. During removal, the power and removal thickness of the removal equipment can be adjusted to fully ensure the safety of the electrode substrate 100. The substrate 100 can be made of materials such as copper foil or aluminum foil. Retaining part of the upper insulating coating 220 is beneficial to improving the protection of the electrode substrate 100 and ensuring normal use of the electrode after the receiving groove 310 is set.

[0073] refer to Figure 2 , Figure 3 and Figure 6 In some embodiments, a lower insulating coating 210 is coated and bonded to a pre-coated area 110, an upper insulating coating 220 is coated on the lower insulating coating 210, and an active layer 300 is coated on the upper insulating coating 220. When setting the receiving groove 310, the active layer 300 covering the upper insulating coating 220 is removed to expose the upper insulating coating 220. The upper insulating coating 220 is then completely removed to expose the lower insulating coating 210. It should be understood that while the upper insulating coating 220 is being completely removed, the lower insulating coating 210 may also be partially worn away. The complete removal of the upper insulating coating 220 is beneficial to increasing the depth of the receiving groove 310 to better accommodate the tab protective adhesive, thereby reducing the distance between adjacent electrodes in the battery and improving the battery's capacity density.

[0074] refer to Figures 9 to 10 According to an embodiment of this application, the battery includes a first electrode 410 and a second electrode 420. The first electrode 410 is the electrode 400 in any of the above embodiments. A tab 430 is connected to the second electrode 420. A receiving groove 310 on the first electrode 410 is provided corresponding to the location of the tab 430 on the second electrode 420. The first electrode 410 and the second electrode 420 can be arranged adjacent to each other. The second electrode 420 includes a base layer 100 and an active layer 300. A portion of the active layer 300 is removed. The first electrode 410 and the active layer 300 together form a groove. The tab 430 is placed in the groove and connected to the base layer 100. The first electrode 410 is provided with a receiving groove 310, which is used to receive the tab protective adhesive 440. It should be noted that the tab 430 is covered with tab protective adhesive 440, which is located outside the groove. The receiving groove 310 receiving the tab protective adhesive 440 is beneficial to make the first electrode 410 and the second electrode 420 fit better, thereby increasing the capacity density of the battery.

[0075] In some embodiments, the first electrode 410 is a positive electrode, and the second electrode 420 is a negative electrode. The second electrode 420 includes a base layer 100 and an active layer 300. A portion of the active layer 300 is removed, and the base layer 100 and the active layer 300 together form a groove. The tab 430 is placed in the groove and connected to the base layer 100. The positive electrode and the negative electrode are attached. The positive electrode has a receiving groove 310 at the connection between the corresponding negative electrode and the tab 430. The receiving groove 310 is used to receive the tab protective adhesive 440. It should be understood that the positive electrode includes an insulating coating 200 at this time. The insulating coating 200 isolates the tab protective adhesive 440 from the base layer 100 of the positive electrode, further preventing the tab 430 connected to the negative electrode from contacting the base layer 100 of the positive electrode at the same time, thereby preventing internal short circuits in the battery and improving battery safety.

[0076] Alternatively, in some other embodiments, the first electrode 410 is a negative electrode and the second electrode 420 is a positive electrode. The negative electrode has a receiving groove 310, and the positive electrode has the aforementioned groove. The groove is used to connect the base layer 100 of the positive electrode with the tab 430. The receiving groove 310 on the negative electrode is used to receive the tab protective adhesive 440 applied to the tab 430, so that adjacent positive and negative electrodes can fit better, avoid gaps, and make full use of the internal space of the battery to improve the battery capacity density.

[0077] Furthermore, the first electrode 410 and / or the second electrode 420 may simultaneously be provided with the aforementioned grooves and receiving slots 310. The grooves on the first electrode 410 are correspondingly provided with the receiving slots 310 on the second electrode 420, and the grooves on the second electrode 420 are correspondingly provided with the receiving slots 310 on the first electrode 410. The first electrode 410 may be provided with multiple grooves and / or receiving slots 310, and the second electrode 420 may also be provided with multiple grooves and / or receiving slots 310. The number of grooves on the first electrode 410 should be the same as the number of receiving slots 310 on the second electrode 420, and the number of grooves on the second electrode 420 should be the same as the number of receiving slots 310 on the first electrode 410. Providing multiple corresponding grooves and receiving slots 310 can lead out multiple tabs 430, thereby improving the charging and discharging performance of the battery.

[0078] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A positive electrode plate, characterized in that, The device includes an insulating coating, a base layer, and an active layer. The insulating coating comprises a lower insulating coating and an upper insulating coating. The base layer has a pre-coating area. The lower insulating coating is applied to the pre-coating area, and the upper insulating coating is applied to the lower insulating coating. Each insulating coating material includes an adhesive, and relative to the base layer, the weight percentage of the adhesive in the upper insulating coating is less than the weight percentage of the adhesive in the lower insulating coating. The adhesive strength of the upper insulating coating is less than that of the lower insulating coating. The active layer is applied to the base layer. The sum of the thicknesses of the lower and upper insulating coatings is less than the thickness of the active layer located outside the pre-coating area. A receiving groove is formed on the active layer opposite to the insulating coating, and the receiving groove is used to correspond to the negative electrode tab. The receiving groove is formed by removing the active layer covering the outside of the insulating coating, exposing the insulating coating to the receiving groove; or, the receiving groove is formed by removing the active layer covering the outside of the insulating coating and part or all of the upper insulating coating.

2. The positive electrode sheet according to claim 1, characterized in that, The active layer is coated on the base layer, and the active layer has a receiving groove formed with the upper insulating coating at a position opposite to the upper insulating coating.

3. The positive electrode sheet according to claim 1, characterized in that, The active layer is coated on the base layer, and the active layer has a receiving groove formed with the lower insulating coating at a position opposite to the lower insulating coating.

4. The positive electrode sheet according to claim 2 or 3, characterized in that, The thickness 'a' of the lower insulating coating ranges from 6μm to 12μm.

5. The positive electrode sheet according to claim 2, characterized in that, The thickness b of the upper insulating coating ranges from 0 μm to 10 μm.

6. A method for producing electrode sheets, characterized in that, include: Setting up an insulating coating: Select a pre-coated area on the substrate and apply at least two layers of insulating coating to the pre-coated area. The material of each insulating coating includes an adhesive, and the weight percentage of the adhesive in the outermost insulating coating is less than the weight percentage of the adhesive in the other insulating coatings relative to the substrate. An active layer is provided: the active layer is coated on the base layer, and the active layer covers the base layer and the insulating coating; To form a receiving groove: remove the active layer covering the outside of the insulating coating to expose the insulating coating and form the receiving groove on the active layer; or, remove the active layer covering the outside of the insulating coating and a portion of the insulating coating to form the receiving groove.

7. The electrode production method according to claim 6, characterized in that, The method for applying the insulating coating includes: A lower insulating coating is applied to the pre-coated area, so that the lower insulating coating adheres to the pre-coated area; An upper insulating coating is applied onto the lower insulating coating to bond the upper insulating coating to the lower insulating coating. Both the lower and upper insulating coatings are made of the adhesive, and the weight percentage of the adhesive in the lower insulating coating is greater than that in the upper insulating coating.

8. The electrode production method according to claim 7, characterized in that, The materials of the lower insulating coating and the upper insulating coating also include ceramic particles. The weight percentage of the adhesive in the lower insulating coating is 1% to 75%, and the weight percentage of the adhesive in the upper insulating coating is 1% to 55%.

9. The electrode production method according to claim 7, characterized in that, The method of setting the receiving groove includes: removing the active layer covering the upper insulating coating to expose the upper insulating coating; Remove part or all of the upper insulating coating that covers the lower insulating coating to form the receiving groove on the active layer.

10. A battery, characterized in that, It includes a first electrode and a second electrode, wherein the first electrode is a positive electrode as described in any one of claims 1 to 5, and the second electrode is connected to a tab, and the receiving groove on the first electrode is provided corresponding to the tab of the second electrode.

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