Positive electrode plate, electrode plate production method and battery

Abstract

Provided in the present application are a positive electrode plate, an electrode plate production method and a battery. The positive electrode plate comprises insulating coatings, a base layer and an active layer, wherein the insulating coatings comprise a lower insulating coating and an upper insulating coating; a pre-coating region is provided on the base layer; the lower insulating coating is coated on the pre-coating region; the upper insulating coating is coated on the lower insulating coating; each insulating coating contains a binder, and relative to the base layer, the weight proportion of the binder in the upper insulating coating is less than that of the binder in the lower insulating coating; the active layer is coated on the base layer; and an accommodating recess is formed by the part of the active layer directly facing the insulating coating and the insulating coating, and the accommodating recess is configured to correspond to a negative tab. The positive electrode plate structure is beneficial to protecting the base layer when the accommodating recess is formed, thereby ensuring the performance of the positive electrode plate. Further provided in the present application are an electrode plate production method and a battery. The electrode plate production method is used for producing the positive electrode plate; and the battery contains the positive electrode plate, and an increase in the capacity density of the battery is benefited.

Description

Positive electrode sheet, electrode sheet production method and battery Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a positive electrode sheet, a method for producing the electrode sheet, and a battery. Background Art

[0002] In battery production, the electrode foil is pre-coated with ceramic. Cleaning the pre-coated ceramic creates grooves that protect the electrode foil during cleaning. The grooves accommodate tab protection glue, increasing the battery's capacity density. However, cleaning the grooves in the electrode is difficult to control. Incomplete cleaning can leave residual active material and / or a thick ceramic coating on the electrode surface, hindering the ability to accommodate the tab protection glue. Excessive cleaning can lead to foil leakage or breakdown, impacting electrode performance.

[0003] Summary of the Invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a positive electrode sheet that is easy to clean and forms a receiving groove, which is beneficial to ensuring the performance of the electrode sheet.

[0005] This application also proposes a method for producing a pole piece;

[0006] The present application also proposes a battery having the above-mentioned electrode.

[0007] According to the first aspect of the present 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 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. The material of each insulating coating includes a binder, and relative to the base layer, the weight proportion of the binder in the upper insulating coating is less than the weight proportion of the binder in the lower insulating coating. The active layer is coated on the base layer, and a receiving groove is formed on the active layer at a position opposite to the insulating coating and the insulating coating. The receiving groove is used to correspond to the negative electrode tab.

[0008] The positive electrode sheet according to the embodiment of the first aspect of the present application has at least the following beneficial effects: the weight proportion of the binder in the upper insulating coating layer is less than the weight proportion of the binder in the lower insulating coating layer, thereby making the upper insulating coating layer less adhesive and easier to remove. This can improve the problem of residual active material and / or thick insulating coating after the positive electrode sheet is provided with a receiving groove, ensure the depth of the receiving groove, and facilitate the receiving groove to accommodate the protective glue. Compared with the upper insulating coating layer, the lower insulating coating layer is more difficult to remove, which can prevent adverse conditions such as electrode sheet foil leakage or electrode sheet breakdown caused by excessive cleaning, and is beneficial to protecting the base layer of the positive electrode sheet, ensuring the normal use of the positive electrode sheet.

[0009] According to the positive electrode sheet of the embodiment of the present application, the active layer is coated on the base layer, and the accommodating groove is formed on the active layer at a position facing the upper insulating coating layer and the upper insulating coating layer.

[0010] According to the positive electrode sheet of the embodiment of the present application, the active layer is coated on the base layer, and the receiving groove is formed on the active layer at a position facing the lower insulating coating layer and the lower insulating coating layer.

[0011] According to the positive electrode sheet of the embodiment of the present application, the thickness a of the lower insulating coating layer is in the range of 6 μm≤a≤12 μm.

[0012] According to the positive electrode sheet of the embodiment of the present application, the thickness b of the upper insulating coating layer is in the range of 0 μm<b≤10 μm.

[0013] According to an embodiment of the present application, the method for producing a pole piece includes the following steps: providing an insulating coating: selecting a pre-coating area on a base layer, and applying at least two layers of insulating coating on the pre-coating area, wherein the material of each insulating coating layer includes a binder, and relative to the base layer, the weight proportion of the binder in the outermost insulating coating layer is less than the weight proportion of the binder in the remaining insulating coating layers;

[0014] Providing an active layer: coating the active layer on the base layer, wherein the active layer covers the base layer and the insulating coating;

[0015] Setting the accommodating groove: removing the active layer covering the outer side of the insulating coating, exposing the insulating coating, and forming the accommodating groove on the active layer; or removing the active layer covering the outer side of the insulating coating and part of the insulating coating to form the accommodating groove.

[0016] The electrode production method according to the embodiment of the present 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 providing at least two layers of insulating coatings containing different weights of binder, the base layer can be protected when the receiving groove is provided, thereby ensuring the integrity of the positive electrode.

[0017] According to the electrode production method of the embodiment of the present application, the method of providing the insulating coating includes:

[0018] Applying a lower insulating coating on the pre-coating area so that the lower insulating coating adheres to the pre-coating area;

[0019] An upper insulating coating is applied on the lower insulating coating so that the upper insulating coating is bonded to the lower insulating coating. The materials of the lower insulating coating and the upper insulating coating both include an adhesive, and the weight proportion of the adhesive in the lower insulating coating is greater than the weight proportion of the adhesive in the upper insulating coating.

[0020] According to the pole piece production method of the embodiment of the present application, the materials of the lower insulating coating and the upper insulating coating also include ceramic particles, the weight proportion of the binder in the lower insulating coating is 1% to 75%, and the weight proportion of the binder in the upper insulating coating is 1% to 55%.

[0021] According to the electrode production method of the embodiment of the present application, the method of providing the receiving groove includes: removing the active layer covering the upper insulating coating layer to expose the upper insulating coating layer;

[0022] The upper insulating coating layer covering the lower insulating coating layer is partially or completely removed to form a receiving groove on the active layer.

[0023] According to an embodiment of the present application, the battery includes a first pole piece and a second pole piece. The first pole piece is the positive pole piece in any of the above embodiments. The second pole piece is connected to a pole lug, and the accommodating groove on the first pole piece is arranged corresponding to the pole lug of the second pole piece.

[0024] The battery according to the embodiment of the present application has at least the following beneficial effects: the second pole piece is connected to the pole tab, the pole tab is covered with pole tab protective glue, the receiving groove can accommodate the pole tab protective glue, and the insulating coating can isolate the pole tab protective glue from contact with the base layer of the first pole piece, further preventing the pole tab from being connected to the first pole piece and the second pole piece at the same time to cause a short circuit, which is beneficial to improving the safety of the battery.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0027] FIG1 is a schematic diagram of a process for producing a pole piece according to an embodiment of the present application;

[0028] FIG2 is a schematic structural diagram of the electrode before the receiving groove is provided in the embodiment of the present application;

[0029] FIG3 is a partial enlarged schematic diagram of point A in FIG2 ;

[0030] FIG4 is a schematic structural diagram of a pole piece provided with a receiving groove according to an embodiment of the present application;

[0031] FIG5 is a partial enlarged schematic diagram of point B in FIG4 ;

[0032] FIG6 is another structural schematic diagram of a pole piece provided with a receiving groove according to an embodiment of the present application;

[0033] FIG7 is a schematic structural diagram of a pole piece including three layers of insulating coating according to an embodiment of the present application;

[0034] FIG8 is a schematic structural diagram of a pole piece including four layers of insulating coating according to an embodiment of the present application;

[0035] FIG9 is a schematic structural diagram of adjacent electrode sheets in a battery according to an embodiment of the present application;

[0036] FIG10 is a partial enlarged schematic diagram of point C in FIG9 .

[0037] Reference numerals: base layer 100, pre-coating area 110;

[0038] Insulation coating 200, lower insulation coating 210, upper insulation coating 220, third insulation coating 230, fourth insulation coating 240;

[0039] Active layer 300, receiving groove 310;

[0040] Pole piece 400 , first pole piece 410 , second pole piece 420 , pole tab 430 , and pole tab protective glue 440 . DETAILED DESCRIPTION

[0041] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0042] In the description of this application, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships 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, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0043] In the description of this application, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0044] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0045] In the description of this application, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0046] The following describes the embodiments of the present application in conjunction with the accompanying drawings:

[0047] 4 and 5 , a pole piece according to an embodiment of the first aspect of the present application includes an insulating coating 200, a base layer 100 and an active layer 300, wherein 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 covered on the lower insulating coating 210, the material of each insulating coating 200 includes a binder, and relative to the base layer 100, the weight proportion of the binder in the upper insulating coating 220 is less than the weight proportion of the binder in the lower insulating coating 210, the upper insulating coating 220 is located at the outermost side of the base layer 100, the active layer 300 is coated on the base layer 100, and a receiving groove 310 is formed on the active layer 300 at a position opposite to the insulating coating 200 and the insulating coating 200, the receiving groove 310 is arranged corresponding to the negative electrode tab, and the receiving groove 310 is used to accommodate the tab protective glue. 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. Thus, the active layer 300 and the insulating coating 200 form a receiving groove 310 for receiving the tab protective glue. Thus, 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 service life of the battery.

[0048] 4 and 5 , in some embodiments, a receiving groove 310 is formed on the active layer 300 at a position opposite to the upper insulating coating 220 and the upper insulating coating 220. This structure allows a portion of the upper insulating coating 220 to be retained, thereby reducing production difficulty. Retaining a portion of the upper insulating coating 220 can provide better protection for the base layer 100, preventing the base layer 100 from being damaged during the production process, which is beneficial to fully ensuring the performance of the positive electrode sheet.

[0049] 6 , in other embodiments, a receiving groove 310 is formed on the active layer 300 at a position opposite to the lower insulating coating 210 and the lower insulating coating 210. This structure completely removes the upper insulating coating 220 on the positive electrode sheet, thereby increasing the receiving space of the receiving groove 310 to better accommodate the tab protective glue, thereby helping to increase the capacity density of the battery.

[0050] Referring to Figures 2, 3, and 6, specifically, the positive electrode sheet includes a base layer 100, an insulating coating layer 200, and an active layer 300. The base layer 100 is provided with a pre-coating area 110, the insulating coating layer 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 at a position opposite the insulating coating layer 200 and the insulating coating layer 200. The receiving groove 310 is used to receive the tab protective glue. It should be understood that the electrode sheet in this embodiment is a electrode sheet after the receiving groove 310 is provided. Its insulating coating layer 200 may only include the lower insulating coating layer 210. The other insulating coating layers 200 are removed during the production process of the electrode sheet. Retaining the lower insulating coating layer 210 can maximize the receiving space of the receiving groove 310, which is beneficial to the receiving groove 310 for receiving the tab protective glue. At the same time, the lower insulating coating layer 210 can also protect the base layer 100, preventing the base layer 100 from being damaged during the production process of the electrode sheet, thereby ensuring the production quality of the electrode sheet.

[0051] It should be noted that the lower insulating coating 210 in this embodiment allows partial wear, but the thickness a of the lower insulating coating 210 should be in 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 accommodation space for the accommodating groove 310 to accommodate the tab protection glue.

[0052] Referring to Figures 3 to 5, in some embodiments, the lower insulating coating 210 has a certain thickness a, and the value range of a is 6μm≤a≤12μm. The thickness of the upper insulating coating 220 can be adjusted according to actual needs, wherein 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 to accommodate the ear protection glue; if the thickness of the lower insulating coating 210 is too small, then when the upper insulating coating 220 is removed, the lower insulating coating 210 is likely to provide insufficient protection for the base layer 100 of the electrode. The thickness a of the lower insulating coating 210 is set between 6μm and 12μm, which can provide better protection for the base layer 100 without occupying too much space in the receiving groove 310. It is beneficial to the fitting of adjacent electrode sheets in the battery, thereby improving the capacity density of the battery.

[0053] 3 to 5 , in some embodiments, the upper insulating coating 220 is located at 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 accommodating groove 310 is set, the upper insulating coating 220 is gradually removed, and its thickness b continues to decrease. Before and after the upper insulating coating 220 is removed, its thickness b is always within the above-mentioned value range. The upper insulating coating 220 provides sufficient removal space for setting the accommodating groove 310, and after removal, part of the upper insulating coating 220 is allowed to remain. Compared with setting a single layer of 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. The lower insulating coating 210 can protect the base layer 100 of the pole piece during removal to prevent the pole piece from being damaged. It should be understood that the sum of the thickness of the lower insulating coating 210 and the thickness of the upper insulating coating 220 should be less than the thickness of the active layer 300 located outside the pre-coating 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 become correspondingly smaller, resulting in insufficient protection of the base layer 100 of the electrode, causing damage to the foil of the base layer 100. Therefore, limiting the thickness b of the upper insulating coating 220 is beneficial to protecting the base layer 100 and preventing the foil of the base layer 100 from being damaged.

[0054] 1 to 4 , the electrode production method according to an embodiment of the present application includes the following steps:

[0055] Providing an insulating coating 200: selecting a pre-coating area 110 on the base layer 100, and applying at least two layers of insulating coating 200 on the pre-coating area 110, wherein the material of each insulating coating 200 includes a binder, and the weight proportion of the binder in the outermost insulating coating 200 relative to the base layer 100 is less than the weight proportion of the binder in the remaining insulating coatings 200;

[0056] Providing an active layer 300: coating the active layer 300 on the base layer 100, wherein the active layer 300 covers the base layer 100 and the insulating coating layer 200;

[0057] Setting the accommodating groove 310: removing the active layer 300 covering the outside of the insulating coating 200 to expose the insulating coating 200 and forming the accommodating groove 310 on the active layer 300; or removing the active layer 300 and part of the insulating coating 200 covering the outside of the insulating coating 200 to form the accommodating groove 310.

[0058] It should be noted that the insulating coating 200 includes a binder. Compared to the insulating coatings 200 located at other locations, the insulating coating 200 located on the outermost side of the base layer 100 has the smallest binder weight ratio. The binder weight ratios of the remaining insulating coatings 200 are all greater than the binder weight ratio of the insulating coating 200 located on the outermost side of the base layer 100. Except for the insulating coating 200 located on the outermost side of the base layer 100, the binder weight ratios of the remaining insulating coatings 200 can be the same or different. The insulating coating 200 located on the outermost side of the base layer 100 has a certain thickness. When removing, since the weight of the adhesive in the insulating coating 200 located on the outermost side of the base layer 100 accounts for the smallest proportion, its adhesion is poorer than that of the other insulating coatings 200 and is easier to remove, so that the receiving groove 310 can be easily formed on the active layer 300. By changing the coating thickness of the insulating coating 200 located on the outermost side 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 glue and improving the capacity density of the battery.

[0059] In addition, except for the insulating coating 200 located on the outermost side of the base layer 100, the adhesive weight in the insulating coating 200 at other positions accounts for a relatively large proportion, and its adhesion is better. Without changing the removal force, the insulating coating 200 with better adhesion is not easy to remove, which can prevent excessive removal from causing adverse conditions such as electrode foil leakage or breakdown, and is beneficial to ensuring the performance of the electrode.

[0060] For example, referring 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 glue, wherein the base layer 100 is a current collector, and the material can be copper foil or aluminum foil, and the lower insulating coating 210 and the upper insulating coating 220 are coated in sequence on the selected pre-coating area 110, wherein 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, and both the lower insulating coating 210 and the upper insulating coating 220 include a binder, and relative to the base layer 100, the upper insulating coating 220 is located at the outermost side of the base layer 100, and the weight proportion of the binder in the upper insulating coating 220 is less than the weight proportion of the binder in the lower insulating coating 210; after coating the upper insulating coating 220, the active layer 300 is coated on the base layer 100, and the active layer 300 covers the base layer 100 and the upper insulating coating 220.

[0061] When setting the receiving groove 310, the pre-coating area 110 can be cleaned and removed by other means such as laser cleaning equipment. First, the active layer 300 covering the upper insulating coating 220 is removed to expose the upper insulating coating 220. The active layer 300 and the upper insulating coating 220 together form the receiving groove 310. The receiving groove 310 is used to accommodate the tab protective glue. In addition, the upper insulating coating 220 is at least partially or completely removed to make the receiving groove 310 deeper. Compared with the weight proportion of the binder in the lower insulating coating 210, the weight proportion of the binder in the upper insulating coating 220 is smaller and easier to remove, which is beneficial to reducing the thickness of the insulating coating so as to better accommodate the tab protective glue. At the same time, the lower insulating coating 210 is more difficult to remove, which is beneficial to protecting the base layer 100 of the pole piece and ensuring the performance of the pole piece.

[0062] In other embodiments, referring to Figures 5 and 7, the insulating coating 200 includes a lower insulating coating 210, an upper insulating coating 220 and a third insulating coating 230, wherein the lower insulating coating 210 is coated on the pre-coating area 110 of the base layer 100, the upper insulating coating 220 is coated and covered on the lower insulating coating 210, and the third insulating coating 230 is coated and covered on the upper insulating coating 220. After coating the third insulating coating 230, the active layer 300 is coated on the base layer 100, and the active layer 300 covers the base layer 100 and the third insulating coating 230, wherein the third insulating coating 230 is located at the outermost side of the base layer 100. Compared with the lower insulating coating 210 and the upper insulating coating 220, the weight proportion of the adhesive in the third insulating coating 230 is smaller, its adhesion is poor, and it is easier to remove, which is beneficial to reducing the thickness of the insulating coating 200 to better accommodate the tab protective glue. At the same time, the upper insulating coating 220 has a smaller weight ratio of the binder than the lower insulating coating 210. Therefore, the weight ratios of the binder in the third insulating coating 230, the upper insulating coating 220, and the lower insulating coating 210 increase in sequence, and the difficulty of removal increases in sequence. When setting the receiving groove 310, at least a portion of the third insulating coating 230 is removed to form the receiving groove 310. This makes it easier to control the force of the removal equipment, improves 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 excessive removal, and improves the quality of the electrode.

[0063] It should be noted that the weight proportion of the binder contained in the lower insulating coating 210 and the upper insulating coating 220 can also be the same, and different materials can be used for the lower insulating coating 210 and the upper insulating coating 220. For example, the lower insulating coating 210 can contain aluminum oxide, and the upper insulating coating 220 can contain silicon dioxide. Aluminum oxide has good chemical stability, and silicon dioxide has high hardness and good wear resistance. Therefore, 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.

[0064] 5 and 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, wherein the lower insulating coating 210 is coated on the pre-coating area 110 of the base layer 100, the upper insulating coating 220 is coated and covered on the lower insulating coating 210, the third insulating coating 230 is coated and covered on the upper insulating coating 220, and the fourth insulating coating 240 is coated and covered on the third insulating coating 230. The fourth insulating coating 240 is located on the outermost side of the base layer 100. Compared with the other three insulating coatings, the binder in the fourth insulating coating 240 is thicker than that in the other three insulating coatings. The weight proportion is small, and the removal difficulty is relatively easy. After the removal equipment removes the active layer 300 covering the fourth insulating coating 240, it can continue to remove the fourth insulating coating 240. The weight proportion of the binder of the fourth insulating coating 240, the third insulating coating 230, the upper insulating coating 220 and the lower insulating coating 210 increases successively, and the removal difficulty increases successively. The removal equipment can gradually increase the force and 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. As a result, it is convenient to control the removal force of the removal equipment, better set the receiving groove 310, and benefit the protection of the pole piece.

[0065] It should be noted that the weight proportion of the binder contained in the lower insulating coating 210, the upper insulating coating 220 and the third insulating coating 230 can also be the same. The lower insulating coating 210, the upper insulating coating 220 and the third insulating coating 230 can contain different materials. For example, the lower insulating coating 210 can contain aluminum oxide, the upper insulating coating 220 can contain silicon dioxide, and the third insulating coating 230 can contain magnesium oxide. Aluminum oxide has good chemical stability, silicon dioxide has high hardness and good wear resistance, and magnesium oxide has high fire resistance. Therefore, the lower insulating coating 210, the upper insulating coating 220 and the third insulating coating 230 can provide different protective layers for the base layer 100 to prevent the base layer 100 of the pole piece from being damaged, which is beneficial to improving the safety of the pole piece.

[0066] It should be understood that the insulating coating 200 can be divided into at least two layers as needed, among which the weight proportion of the adhesive in the insulating coating 200 located on the outermost side of the base layer 100 is the smallest, and its adhesion is poorer than that of the insulating coating 200 at other positions, and it is easier to remove. Therefore, it is convenient to control the degree of removal of the insulating coating 200. While providing the accommodating groove 310 on the pole piece, it can protect the base layer 100 of the pole piece and ensure the use of the pole piece.

[0067] 2 to 4, in some embodiments, when providing the insulating coating 200, first, a pre-coating area 110 is selected according to the size of the tab protective glue, and a lower insulating coating 210 is coated on the pre-coating area 110, so that the lower insulating coating 210 is bonded to the pre-coating area 110, and then an upper insulating coating 220 is coated on the lower insulating coating 210, and the upper insulating coating 220 covers and bonds to the lower insulating coating 210. The materials of the lower insulating coating 210 and the upper insulating coating 220 both include an adhesive, and the lower insulating coating 210 is preferably a plurality of layers. The weight proportion of the adhesive in the insulating coating 210 is greater than the weight proportion of the adhesive in the upper insulating coating 220, so that 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 that the removal force remains unchanged, 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.

[0068] Specifically, since the weight proportion of the 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 the 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 for removing the upper insulating coating 220 is met but the removal force for removing the lower insulating coating 210 is not met, no matter how the position of the removal device is adjusted, the lower insulating coating 210 cannot be removed. Compared with setting a single-layer insulating coating 200, this solution can control the removal degree by setting the removal force, such as adjusting the power of the laser cleaning device to control the removal force, without having to adjust the position of the removal device to achieve the removal of the insulating coating 200, thereby facilitating the control of the removal degree of the insulating coating 200 in the pre-coating area 110, avoiding the electrode being punctured during removal, and benefiting to increasing the quality of the electrode.

[0069] It should be noted that the binder can be one or more combinations of polyvinylidene fluoride, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoroethylene or styrene-butadiene rubber.

[0070] 2 to 5 , in some embodiments, the material of the lower insulating coating 210 and the upper insulating coating 220 includes ceramic particles, which may be one or more combinations of aluminum oxide, 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.

[0071] In addition, the weight proportion of the binder contained in the lower insulating coating 210 is 1% to 75%, and the weight proportion of the binder contained in the upper insulating coating 220 is 1% to 55%. It should be noted that the upper insulating coating 220 is located on the outermost side of the base layer 100, and the weight proportion of the binder in the upper insulating coating 220 is less than the weight proportion of the binder contained in the lower insulating coating 210. Therefore, 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. The lower insulating coating 210 is used to protect the electrode base layer 100, and the upper insulating coating 220 is used to be removed to form the receiving groove 310. When the receiving groove 310 is formed during removal, the upper insulating coating 220 is allowed to partially remain, and the lower insulating coating 210 is allowed to be partially removed. Therefore, when the receiving groove 310 is provided, it can ensure that the receiving groove 310 has good accommodation for the tab protection glue, and can also protect the base layer 100 of the electrode to avoid damage to the base layer 100 when removing the insulating coating.

[0072] 2 to 5 , in some embodiments, a lower insulating coating 210 is coated and bonded to the pre-coating 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 , and then the upper insulating coating 220 covering the lower insulating coating 210 is removed. The upper insulating coating 220 can be partially removed or completely removed. It should be understood that the greater the degree of removal, the greater the depth of the receiving groove 310 , and accordingly, the less protection the base layer 100 has. 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 actual conditions.

[0073] 2 to 5 , in some embodiments, a lower insulating coating 210 is coated and bonded to a pre-coating 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 a receiving groove 310 , the active layer 300 covering the upper insulating coating 220 is removed to expose the upper insulating coating 220 , and the upper insulating coating 220 is partially removed. During removal, the power and 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 substrate 100 of the electrode and ensuring the normal use of the electrode after the receiving groove 310 is set.

[0074] 2 , 3 and 6 , in some embodiments, a lower insulating coating 210 is coated and bonded to the pre-coating 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 accommodating 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 completely removed to expose the lower insulating coating 210 . It should be understood that while completely removing the upper insulating coating 220 , 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 accommodating groove 310 to better accommodate the tab protective glue, thereby reducing the distance between adjacent pole pieces in the battery and improving the capacity density of the battery.

[0075] 9 to 10, a battery according to an embodiment of the present application includes a first electrode piece 410 and a second electrode piece 420, wherein the first electrode piece 410 is the electrode piece 400 in any of the above embodiments, and the second electrode piece 420 is connected to a pole ear 430, and the receiving groove 310 on the first electrode piece 410 is provided corresponding to the location of the pole ear 430 of the second electrode piece 420, wherein the first electrode piece 410 and the second electrode piece 420 can be provided adjacent to each other, and the second electrode piece 420 includes a base layer 100 and an active layer 300, and a portion of the active layer 300 is removed. The base layer 100 and the active layer 300 jointly form a groove, the tab 430 is placed in the groove and connected to the base layer 100, and the first pole piece 410 is provided with a receiving groove 310, which is used to accommodate the tab protective glue 440. It should be noted that the tab 430 is covered with the tab protective glue 440, and the tab protective glue 440 is located outside the above-mentioned groove. The receiving groove 310 accommodates the tab protective glue 440, which is beneficial to better fit the first pole piece 410 and the second pole piece 420, thereby increasing the capacity density of the battery.

[0076] In some embodiments, the first electrode sheet 410 is a positive electrode sheet, the second electrode sheet 420 is a negative electrode sheet, the second electrode sheet 420 includes a base layer 100 and an active layer 300, and a portion of the active layer 300 is removed. The base layer 100 and the active layer 300 together form a groove, and the tab 430 is placed in the groove and connected to the base layer 100. The positive electrode sheet is bonded to the negative electrode sheet, and the positive electrode sheet is provided with a receiving groove 310 at the connection between the corresponding negative electrode sheet and the tab 430. The receiving groove 310 is used to accommodate the tab protection glue 440. It should be understood that at this time, the positive electrode sheet includes an insulating coating 200, and the insulating coating 200 isolates the tab protection glue 440 from the base layer 100 of the positive electrode sheet, further preventing the tab 430 connected to the negative electrode sheet from contacting the base layer 100 of the positive electrode sheet at the same time, thereby preventing internal short circuit of the battery and improving the safety of the battery.

[0077] Alternatively, in other embodiments, the first electrode sheet 410 is a negative electrode sheet, the second electrode sheet 420 is a positive electrode sheet, a receiving groove 310 is provided on the negative electrode sheet, and the above-mentioned groove is provided on the positive electrode sheet. The above-mentioned groove is used to connect the base layer 100 of the positive electrode sheet with the pole ear 430, and the receiving groove 310 on the negative electrode sheet is used to accommodate the pole ear protection glue 440 attached to the pole ear 430, so that the adjacent positive and negative electrode sheets can fit better and avoid gaps, which is beneficial to fully utilize the internal space of the battery and improve the capacity density of the battery.

[0078] In addition, the above-mentioned grooves and accommodating grooves 310 may be provided on the first pole piece 410 and / or the second pole piece 420 at the same time. The grooves on the first pole piece 410 are arranged corresponding to the accommodating grooves 310 on the second pole piece 420, and the grooves on the second pole piece 420 are arranged corresponding to the accommodating grooves 310 on the first pole piece 410. The first pole piece 410 may be provided with multiple grooves and / or accommodating grooves 310, and the second pole piece 420 may also be provided with multiple grooves and / or accommodating grooves 310. The number of grooves on the first pole piece 410 should be the same as the number of accommodating grooves 310 on the second pole piece 420, and the number of grooves on the second pole piece 420 should be the same as the number of accommodating grooves 310 on the first pole piece 410. The provision of multiple corresponding grooves and accommodating grooves 310 can lead to multiple pole ears 430, thereby improving the charging and discharging performance of the battery.

[0079] The embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A positive electrode sheet, comprising an insulating coating, a base layer and an active layer, wherein 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, and the upper insulating coating is coated on the lower insulating coating, the material of each insulating coating comprises a binder, and relative to the base layer, the weight proportion of the binder in the upper insulating coating is less than the weight proportion of the binder in the lower insulating coating, the active layer is coated on the base layer, and a receiving groove is formed on the active layer at a position opposite to the insulating coating and the insulating coating, and the receiving groove is used to correspond to the negative electrode tab.

2. The positive electrode sheet according to claim 1, wherein: The active layer is coated on the base layer, and the receiving groove is formed on the active layer at a position facing the upper insulating coating layer and the upper insulating coating layer.

3. The positive electrode sheet according to claim 1, wherein: The active layer is coated on the base layer, and the receiving groove is formed on the active layer at a position facing the lower insulating coating layer and the lower insulating coating layer.

4. The positive electrode sheet according to claim 2 or 3, wherein: The thickness a of the lower insulating coating layer is in the range of 6 μm≤a≤12 μm.

5. The positive electrode sheet according to claim 2, wherein: The thickness b of the upper insulating coating layer is in the range of 0 μm<b≤10 μm.

6. A method for producing a pole piece, comprising: Providing an insulating coating: selecting a pre-coating area on the base layer, and coating at least two layers of insulating coating on the pre-coating area, wherein the material of each insulating coating layer includes a binder, and relative to the base layer, the weight proportion of the binder in the outermost insulating coating layer is less than the weight proportion of the binder in the remaining insulating coating layers; Providing an active layer: coating the active layer on the base layer, wherein the active layer covers the base layer and the insulating coating layer; Setting a receiving groove: removing the active layer covering the outside of the insulating coating to expose the insulating coating and forming the receiving groove on the active layer; or removing the active layer covering the outside of the insulating coating and part of the insulating coating to form the receiving groove.

7. The pole piece production method according to claim 6, wherein: The method for providing the insulating coating comprises: Applying a lower insulating coating on the pre-coating area so that the lower insulating coating adheres to the pre-coating area; An upper insulating coating is coated on the lower insulating coating so that the upper insulating coating is bonded to the lower insulating coating. The materials of the lower insulating coating and the upper insulating coating both include the adhesive, and the weight proportion of the adhesive in the lower insulating coating is greater than the weight proportion of the adhesive in the upper insulating coating.

8. The pole piece production method according to claim 7, wherein: The materials of the lower insulating coating layer and the upper insulating coating layer also include ceramic particles. The weight proportion of the binder in the lower insulating coating layer is 1% to 75%, and the weight proportion of the binder in the upper insulating coating layer is 1% to 55%.

9. The pole piece production method according to claim 7, wherein: The method for providing the receiving groove includes: removing the active layer covering the upper insulating coating layer to expose the upper insulating coating layer; The upper insulating coating layer covering the lower insulating coating layer is partially or completely removed to form the receiving groove on the active layer.

10. A battery, comprising a first pole piece and a second pole piece, wherein the first pole piece is the positive pole piece according to any one of claims 1 to 5, and a pole lug is connected to the second pole piece, and the receiving groove on the first pole piece is arranged corresponding to the pole lug of the second pole piece.

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