Electrode sheet, electrode sheet coating apparatus and coating method therefor, and battery

Abstract

The present application provides an electrode sheet, an electrode sheet coating apparatus and a coating method therefor, and a battery. The electrode sheet comprises a current collector, a first electrode coating layer, and a second electrode coating layer, wherein the first electrode coating layer is at least arranged on a first surface of one side of the current collector, the second electrode coating layer is stacked on a first surface of the side of the first electrode coating layer facing away from the current collector, a second peripheral side edge of the second electrode coating layer exceeds a first peripheral side edge of the first electrode coating layer to form a filling portion, and the thickness of the filling portion is greater than the thickness of the first electrode coating layer.

Description

Electrode sheets, electrode sheet coating apparatus and coating method, and batteries

[0001] This application claims priority to Chinese patent applications filed on March 21, 2025, with application numbers 202510344375.8 and 202520503405.0, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of lithium battery manufacturing technology, specifically to electrode sheets, electrode sheet coating apparatus and coating method, and batteries. Background Technology

[0003] In the production process of lithium batteries, the manufacturing of electrode sheets plays a crucial role. Statistics show that approximately 70% of the quality of a lithium battery is related to the quality of the electrode sheets. The manufacturing process of lithium battery electrode sheets includes slurry preparation, coating, drying, and rolling. During the coating process, to prevent the adhesive from evaporating too quickly near the substrate during drying, which would reduce the amount of residual adhesive and make the electrode sheets prone to detachment, a layered coating method is used in related technologies. The most common layered coating method involves applying two layers of slurry, with the lower slurry layer being wider and the upper slurry layer being narrower. Invention Overview

[0004] However, while this layered coating method can solve the problem of electrode sheet detachment, it is prone to causing heavy separation marks between the upper and lower layers and excessive thickness difference in the thinned area, resulting in poor appearance and reducing battery production yield.

[0005] In a first aspect, embodiments of this application provide an electrode sheet, comprising:

[0006] current collector;

[0007] A first electrode coating is disposed on at least one surface of the current collector; and,

[0008] The second electrode coating is stacked on the first surface of the first electrode coating on the side away from the current collector. The second peripheral edge of the second electrode coating extends beyond the first peripheral edge of the first electrode coating, and the extended portion is arranged around the outer peripheral side of the first electrode coating, forming a filling portion on the outer peripheral side of the first electrode coating. In the stacking direction of the first electrode coating and the second electrode coating, the thickness of the filling portion is greater than the thickness of the first electrode coating.

[0009] Secondly, embodiments of this application provide an electrode sheet coating apparatus, comprising:

[0010] The coating die and the at least two supply flow paths, the coating die is formed with a first discharge port and a second discharge port, and is configured to respectively spray slurry towards the current collector, the first discharge port is in communication with one of the supply flow paths, and the second discharge port is in communication with the other supply flow path;

[0011] The electrode sheet coating device further comprises:

[0012] The storage assembly is respectively arranged on the two supply flow paths, and is configured to store the slurry after the magnetic treatment;

[0013] The fine filtration assembly is respectively arranged on the two supply flow paths, and is located between the storage assembly and the coating die, and is configured to perform fine filtration treatment on the slurry after the magnetic treatment; and

[0014] The material collecting assembly is respectively arranged on the two supply flow paths, and is located between the fine filtration assembly and the coating die, and is configured to collect the slurry after the fine filtration treatment.

[0015] In a third aspect, an embodiment of the present application provides an electrode sheet coating method, the electrode sheet coating method comprising:

[0016] providing a current collector;

[0017] providing a first slurry and a second slurry;

[0018] coating the first slurry on at least one first surface of the current collector;

[0019] drying the current collector coated with the first slurry in a vacuum environment to form a first electrode coating on the current collector;

[0020] coating the second slurry on a second surface of the first electrode coating, wherein the coating amount of the second slurry is greater than the coating amount of the first slurry, so that part of the second slurry flows to a first circumferential edge position of the first electrode coating and forms a filling part on the circumferential side of the first electrode coating;

[0021] drying the current collector coated with the second slurry in a vacuum environment to form a second electrode coating on the first electrode coating;

[0022] rolling the current collector with the first electrode coating and the second electrode coating stacked thereon to form an electrode sheet with a double-layer structure.

[0023] In a fourth aspect, an embodiment of the present application provides a battery, the battery comprising a battery sheet. Advantages

[0024] In the embodiments of the present application, the electrode sheet comprises a current collector, a first electrode coating layer and a second electrode coating layer which are stacked; the first electrode coating layer is arranged on at least a first surface of one side of the current collector; the second electrode coating layer is stacked on a first surface of a side of the first electrode coating layer away from the current collector; the width of the second electrode coating layer is greater than that of the first electrode coating layer, so that the second peripheral side edge of the second electrode coating layer is arranged beyond the first peripheral side edge of the first electrode coating layer; since the slurry for forming the second electrode coating layer is a fluid, the peripheral side of the second electrode coating layer will flow to the outer peripheral side of the first electrode coating layer during the coating process, so that after the slurry is dried, the part of the second electrode coating layer beyond the first electrode coating layer will be arranged around the outer peripheral side of the first electrode coating layer, thereby forming a filling part; the filling part can fill the gap between the first electrode coating layer and the current collector, thereby reducing the separation marks at the edges of the first electrode coating layer and the second electrode coating layer; and the thickness of the filling part is greater than that of the first electrode coating layer, so that the thickness difference of the thinning area of the outer peripheral side of the first electrode coating layer is also reduced, so that the appearance defect of the electrode sheet can be improved, and the production yield of the battery can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a structural schematic diagram of an electrode sheet in the related art;

[0026] FIG. 2 is a structural schematic diagram of an electrode sheet provided by a possible implementation manner of the present application;

[0027] FIG. 3 is a structural diagram of an electrode sheet coating device provided by a possible implementation manner of the present application;

[0028] FIG. 4 is a structural schematic diagram of an electrode sheet coating die provided by a possible implementation manner of the present application;

[0029] FIG. 5 is an enlarged schematic diagram of a partial A in FIG. 4;

[0030] FIG. 6 is a flowchart of an electrode sheet coating method provided by a possible implementation manner of the present application.

[0031] BRIEF DESCRIPTION OF DRAWINGS:

[0032] 100, electrode sheet; 1, current collector; 11, first surface; 2, first electrode coating; 21, second surface; 22, first peripheral edge; 3, second electrode coating; 31, second peripheral edge; 32, filling part; 200, electrode sheet coating device; 201, coating die; 2011, first discharge port; 2012, second discharge port; 2013, first flow channel; 2014, second flow channel; 2015, first feeding port; 2016, second feeding port; 202, feeding flow path; 203, storage assembly; 2031, storage tank; 204, fine filtration assembly; 2041, fine filtration part; 20411, first-stage filtration; 20412, second-stage filtration; 20413, third-stage filtration; 205, collection assembly; 2051, collection tank; 206, batching assembly; 2061, batching part; 20611, batching tank; 20612, stirring part; 207, demagnetization assembly; 2071, demagnetization part; 20711, first-stage demagnetization; 20712, second-stage demagnetization; 20713, third-stage demagnetization; 208, coarse filtration assembly; 2081, coarse filtration part; 209, feeding assembly; 2091, feeding pipeline. Embodiments of the present application

[0033] In a first aspect, an embodiment of the present application provides an electrode sheet 100, as shown in FIG. 2, which comprises a current collector 1, a first electrode coating 2, and a second electrode coating 3; the first electrode coating 2 is arranged on at least one first surface 11 of one side of the current collector 1; the second electrode coating 3 is arranged on the first surface 11 of the side of the first electrode coating 2 away from the current collector 1, and the second peripheral edge 31 of the second electrode coating 3 is arranged beyond the first peripheral edge 22 of the first electrode coating 2, and the overhanging part is arranged around the outer peripheral side of the first electrode coating 2 to form a filling part 32 on the outer peripheral side of the first electrode coating 2; in the stacking direction of the first electrode coating 2 and the second electrode coating 3, the thickness of the filling part 32 is greater than the thickness of the first electrode coating 2.

[0034] It can be understood that the manufacturing process of the lithium battery electrode sheet 100 includes slurry mixing, coating, drying, and rolling. The conventional electrode sheet 100 coating process usually adopts single-layer coating. When the coating is completed and the slurry is dried, the adhesive (such as SBR) in the slurry volatilizes faster at the position close to the current collector 1, so that the adhesive content of the electrode coating on the side close to the current collector 1 is reduced, thereby reducing the peeling force between the dried electrode coating and the current collector 1. In the process of battery assembly and charging and discharging, the electrode sheet 100 coating is prone to fall off, thereby affecting the battery performance, and even triggering the safety hazard of the battery due to short circuit.

[0035] In order to increase the peeling force between the electrode coating and the current collector 1, the related art proposes to form the coating of the electrode sheet 100' by using a layered coating method. That is, referring to FIG. 1, the first electrode coating 2' and the second electrode coating 3' are coated on the current collector 1' in sequence, compared with a single-layered thicker electrode coating, the phenomenon of binder migration to the surface during the drying process can be effectively alleviated, the uniformity of binder distribution is improved, which is beneficial to improve the peeling strength and cycle stability of the battery; and generally, the first electrode coating 2' close to the current collector 1' is wider, and the second electrode coating 3' away from the current collector 1' is narrower; although the layered coating can solve the hidden danger of the coating of the electrode sheet 100' falling off, due to the different widths of the first electrode coating 2' and the second electrode coating 3', the division marks at the edge positions of the two electrode coatings are obvious.

[0036] And at the edge position of the first electrode coating 2', there is no second electrode coating 3', that is, there is only one layer of electrode coating at this position, thereby forming a thinned area; at the middle position of the current collector 1', the total thickness of the electrode coating is set as the sum of the thickness T1' of the first electrode coating 2' and the thickness T2' of the second electrode coating 3', the thickness of the electrode coating at the thinned area position is equivalent to the thickness T1' of the first electrode coating 2', the thickness difference of the electrode coating at the thinned area position is equivalent to the thickness T2' of the second electrode coating 3', and the thickness difference of the electrode coating at the thinned area position is large; in this way, the layered coating method provided by the related art is easy to cause the appearance defect of heavy upper and lower layer division marks and too large thickness difference of the thinned area, thereby reducing the production yield of the battery.

[0037] In the embodiment of the present application, referring to FIG. 2, the electrode sheet 100 includes the current collector 1, the first electrode coating 2 and the second electrode coating 3 which are stacked; the first electrode coating 2 is arranged on the first surface 11 of one side of the current collector 1; the second electrode coating 3 is stacked on the first surface 11 of the side of the first electrode coating 2 away from the current collector 1; by setting the width of the second electrode coating 3 to be greater than the width of the first electrode coating 2, the second peripheral edge 31 of the second electrode coating 3 is arranged beyond the first peripheral edge 22 of the first electrode coating 2; since the slurry for forming the second electrode coating 3 is a fluid, during the coating process, the excess part of the peripheral side of the second electrode coating 3 will flow to the outer peripheral side of the first electrode coating 2, so that after the slurry is dried, the part of the second electrode coating 3 beyond the first electrode coating 2 will be annularly arranged on the outer peripheral side of the first electrode coating 2, thereby forming a filling part 32; the filling part 32 can fill the step between the first electrode coating 2 and the current collector 1, thereby reducing the division marks at the edges of the first electrode coating 2 and the second electrode coating 3.

[0038] And, in the coating process, the excess part of the second electrode coating layer 3 on the periphery side will flow to the outer periphery side of the first electrode coating layer 2, so that after the slurry is dried, the part of the second electrode coating layer 3 exceeding the first electrode coating layer 2 will be annularly arranged on the outer periphery side of the first electrode coating layer 2, thereby forming a filling part 32; on the outer periphery side of the first electrode coating layer 2, there is only one layer of electrode coating, that is, the filling part 32, so that a thinning area is formed on the outer periphery side of the first electrode coating layer 2; at the middle position of the current collector 1, the total thickness of the electrode coating layer is set to be the sum of the thickness T1 of the first electrode coating layer 2 and the thickness T2 of the second electrode coating layer 3, and the thickness of the electrode coating layer at the thinning area position is set to be the thickness T3 of the filling part 32, so the thickness difference of the electrode coating layer at the thinning area position is ΔT=(T1+T2)-T3, by setting the thickness T3 of the filling part 32 to be greater than the thickness T1 of the first electrode coating layer 2, so the thickness difference ΔT is less than the thickness T2 of the second electrode coating layer 3; compared with the related art, the thickness difference at the thinning area position in the present application is small, thereby improving the situation that the thickness difference of the electrode coating layer at the thinning area is large in the related art.

[0039] In this way, by setting the width of the second electrode coating layer 3 to be greater than the width of the first electrode coating layer 2, the second periphery edge 31 of the second electrode coating layer 3 is arranged to exceed the first periphery edge 22 of the first electrode coating layer 2, and the excess part thereof is annularly arranged on the outer periphery side of the first electrode coating layer 2 and forms a filling part 32 on the outer periphery side of the first electrode coating layer 2, and in the stacking direction of the first electrode coating layer 2 and the second electrode coating layer 3, the thickness of the filling part 32 is greater than the thickness of the first electrode coating layer 2; the appearance defect that the split marks at the edges of the first electrode coating layer 2 and the second electrode coating layer 3 are obvious and the thickness difference of the electrode coating layer at the thinning area position is too large can be improved, thereby improving the production yield of the battery.

[0040] In some embodiments, the total amount of slurry of the second electrode coating layer 3 is greater than the total amount of slurry of the first electrode coating layer 2; that is, in the convex coating process of the first electrode coating layer 2 and the second electrode coating layer 3, by setting the total amount of slurry of the second electrode coating layer 3 to be greater than the total amount of slurry of the first electrode coating layer 2, it is ensured that when the second electrode coating layer 3 is coated, there is enough slurry to flow to the outer periphery side of the first electrode coating layer 2, and when the filling part 32 is formed on the outer periphery side of the first electrode coating layer 2, the thickness T3 of the filling part 32 can be greater than the thickness T1 of the first electrode coating layer 2.

[0041] And, in some embodiments, in the stacking direction of the first electrode coating layer 2 and the second electrode coating layer 2, the thickness T3 of the filling part 32 is equal to the sum of the thickness T1 of the first electrode coating layer 2 and the thickness T3 of the second electrode coating layer 3.

[0042] In some embodiments, the slurry of the first electrode coating layer 2 comprises an active material, a conductive agent and a binder; the slurry of the second electrode coating layer 3 comprises an active material, a conductive agent and a binder; the active material, the conductive agent and the binder in the slurry of the first electrode coating layer 2 are proportioned in a first preset ratio; the active material, the conductive agent and the binder in the slurry of the second electrode coating layer 3 are proportioned in a second preset ratio.

[0043] It can be understood that, in order to improve the peeling force between the electrode coating layer and the current collector and ensure the cycle performance of the battery, the content of the binder generally needs to be set. The content of the binder is generally expressed in mass percentage (wt%), i.e., the mass percentage of the binder in the total mass of the electrode slurry. In some embodiments, the mass percentage of the binder in the first electrode coating layer 2 is set to X, and the mass percentage of the binder in the second electrode coating layer 3 is set to Y; wherein, .

[0044] In the present embodiment, the first electrode coating layer 2 is arranged close to the current collector 1, and the second electrode coating layer 3 is arranged away from the current collector 1; by increasing the content of the binder in the first electrode coating layer 2, the mass percentage of the binder in the first electrode coating layer 2 is set to be relatively large, which can improve the peeling force between the first electrode coating layer 2 and the current collector 1, thereby reducing the resistance of the electrode sheet 100; and the mass percentage of the binder in the second electrode coating layer 3 is set to be relatively small, so that the second electrode coating layer 3 can fill more active material and conductive agent, thereby improving the cycle performance of the battery.

[0045] Further, after increasing the mass percentage of the binder in the first electrode coating layer 2, the ratio of the mass percentage of the binder in the second electrode coating layer 3 to the mass percentage of the binder in the first electrode coating layer 2 is set to be in the range of 0.2-0.8; when the ratio of the mass percentage of the binder in the second electrode coating layer 3 to the mass percentage of the binder in the first electrode coating layer 2 is greater than 0.8, the mass percentage of the binder in the first electrode coating layer 2 is approximately the same as the mass percentage of the binder in the second electrode coating layer 3, the content of the binder in the first electrode coating layer 2 increases slightly, and the peeling force between the first electrode coating layer 2 and the current collector 1 does not improve significantly; when the ratio of the mass percentage of the binder in the second electrode coating layer 3 is greater than 0.2, the content of the binder in the first electrode coating layer 2 is too large, although the peeling force between the first electrode coating layer 2 and the current collector 1 can be greatly improved, the content of the active material and the conductive agent in the first electrode coating layer 2 is too small, thereby affecting the cycle performance of the battery.

[0046] The application does not make specific restrictions on the ratio of the mass percentage of the binder in the second electrode coating 3 to the mass percentage of the binder in the first electrode coating 2. The ratio of the mass percentage of the binder in the second electrode coating 3 to the mass percentage of the binder in the first electrode coating 2 can be set to 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or a range composed of any two of them.

[0047] The application does not make specific restrictions on the thickness of the first electrode coating 2 and the second electrode coating 3. Referring to FIG. 2, the thickness T1 of the first electrode coating 2 can be 0.5 μm to 5 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or a range composed of any two of them. Controlling the thickness T1 of the first electrode coating 2 within a suitable range is conducive to the close connection between the first electrode coating 2 and the current collector 1, ensures the safety performance of the battery, does not affect the energy density of the battery, and is also conducive to cost control.

[0048] Similarly, the thickness T2 of the second electrode coating 3 can be 1.5 μm to 8 μm, for example, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or a range composed of any two of them. Controlling the thickness T2 of the second electrode coating 3 within a suitable range is conducive to the close connection between the second electrode coating 3 and the current collector 1, ensures the safety performance of the battery, does not affect the energy density of the battery, and is also conducive to cost control.

[0049] Furthermore, the thickness of the first electrode coating 2 and the second electrode coating 3 can be the same or different. In some embodiments, the thickness of the first electrode coating 2 and the second electrode coating 3 is different. When the thickness T1 of the first electrode coating 2 and the thickness T2 of the second electrode coating 3 are different, the thickness T2 of the second electrode coating 3 can be greater than the thickness T1 of the first electrode coating 2, or less than the thickness T1 of the first electrode coating 2.

[0050] In another embodiment, the thickness T1 of the first electrode coating 2 and the thickness T2 of the second coating 3 are the same. It can be known that when the first electrode coating 2 and the second electrode coating 3 are dried and then rolled, the second electrode coating 3 is subjected to a greater rolling force than the first electrode coating 2. To ensure that the thickness T1 of the first electrode coating 2 and the thickness T2 of the second electrocoating 3 are the same, the total amount of slurry of the second electrode coating 3 must be greater than that of the first electrode coating 2, the content of the binder in the second electrode coating 3 is lower, and the content of the active material and the conductive agent is higher. Therefore, after rolling under a larger rolling force, the active material in the slurry of the second electrode coating 3 is more uniformly distributed and has a greater density, thereby making the energy density of the second electrode coating 3 greater and improving the cycle performance of the battery.

[0051] In some embodiments, the width of the filling part 32 is set as W in the direction away from the first peripheral edge 22 of the first electrode coating 2, where 0.1mm≤W≤0.5mm. The filling part 32 is set to reduce the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3. When the width W of the filling part 32 is less than 0.1mm, the filling part 32 on the outer periphery of the first electrode coating 2 is too small to reduce the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3. When the width W of the filling part 32 is greater than 0.5mm, the filling part 32 on the outer periphery of the first electrode coating 2 is too large, that is, too much slurry is accumulated on the outer periphery of the first electrode coating 2, which is prone to waste of slurry. The width W of the filling part 32 is set to 0.1mm-0.5mm, which can save slurry while ensuring the effect of reducing the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3.

[0052] The width of the filling part 32 is not specifically limited in the present application, which can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or a range formed by any two of them.

[0053] In some embodiments, the thickness of the first electrode coating 2 is set as T1, the thickness of the second electrode coating 3 is set as T2, and the thickness of the filling part 32 is set as T3 in the stacking direction of the first electrode coating 2 and the second electrode coating 3, where 0≤(T1+T2)-T3≤9μm. The filling part 32 is set to reduce the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3. When the thickness difference of the electrode coating at the thinning area is less than 0μm, the surface of the filling part 32 exceeds the surface of the second electrode coating 3, that is, too much slurry is accumulated on the outer periphery of the first electrode coating 2, which is prone to waste of slurry. When the thickness difference of the electrode coating at the thinning area is greater than 9μm, the thickness of the filling part 32 is too small to reduce the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3. The thickness difference of the electrode coating at the thinning area is set to 0-9μm, which can save slurry while ensuring the effect of reducing the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3.

[0054] The thickness difference of the electrode coating at the thinning area is not specifically limited in the present application. The thickness difference of the electrode coating at the thinning area can be set to 0μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm or a range formed by any two of them.

[0055] The type of the electrode sheet 100 is not specifically limited in the present application. The electrode sheet 100 can be a positive electrode sheet or a negative electrode sheet. When the electrode sheet 100 is set as a positive electrode sheet, the electrode sheet 100 comprises a positive current collector, a first positive electrode coating layer and a second positive electrode coating layer which are sequentially stacked, and the positive current collector is set as an aluminum foil; when the electrode sheet 100 is set as a negative electrode sheet, the electrode sheet 100 comprises a negative current collector, a first negative electrode coating layer and a second negative electrode coating layer which are sequentially stacked, and the negative current collector is set as a copper foil.

[0056] In a second aspect, based on the electrode sheet 100, the present application further provides an electrode sheet coating device 200. Referring to FIGS. 4-6, the electrode sheet coating device 200 comprises a coating die head 201 and two feeding flow paths 202, the coating die head 201 is provided with a first discharge port 2011 and a second discharge port 2012 which are set to respectively spray slurry towards the current collector 1, the first discharge port 2011 is in communication with one of the two feeding flow paths 202, and the second discharge port 2012 is in communication with the other feeding flow path 202; the electrode sheet coating device 200 further comprises a storage assembly 203, a fine filtration assembly 204 and a collection assembly 205; the storage assembly 203 is separately arranged on the two feeding flow paths 202 and is set to store the slurry after magnetic treatment; the fine filtration assembly 204 is separately arranged on the two feeding flow paths 202 and is located between the storage assembly 203 and the coating die head 201, and is set to perform fine filtration treatment on the slurry after magnetic treatment; the collection assembly 205 is separately arranged on the two feeding flow paths 202 and is located between the fine filtration assembly 204 and the coating die head 201, and is set to collect the slurry after fine filtration treatment.

[0057] In the embodiments of the present application, the electrode sheet coating device 200 comprises a coating die head 201 and two feeding flow paths 202, the first discharge port 2011 and the second discharge port 2012 on the coating die head 201 are set to respectively spray slurry towards the current collector 1 to form a first electrode coating layer 2 and a second electrode coating layer 3 on the current collector 1 respectively; the first discharge port 2011 and the second discharge port 2012 are in communication with the two feeding flow paths 202 respectively; on each feeding flow path 202, the slurry after magnetic treatment is stored in the storage assembly 203, and before being conveyed to the corresponding discharge port on the coating die head 201, the slurry will pass through the fine filtration assembly 204 for fine filtration treatment, thereby removing micrometer or even sub-micrometer particles in the slurry, which can significantly reduce the impurity content, thereby improving the appearance defect of particle scratches on the coating layer of the electrode sheet 100 in the layered thin coating process; at the same time, the slurry is discharged slowly after fine filtration, and the collection assembly 205 is arranged between the fine filtration assembly 204 and the coating die head 201 to collect the slurry after fine filtration treatment, thereby ensuring the slurry feeding amount and feeding speed, and further ensuring the uniformity of slurry coating and improving the appearance defect of the coating layer of the electrode sheet 100.

[0058] In some embodiments, referring to FIG. 4, the fine filtration assembly 204 includes two fine filtration units 2041, which are respectively arranged on the two supply flow paths 202. The fine filtration unit 2041 includes a first-stage filtration 20411, a second-stage filtration 20412, and a third-stage filtration 20413. The first-stage filtration 20411 is arranged between the storage assembly 203 and the coating die 201, and is configured to perform coarse filtration on the slurry after the magnetic removal treatment. The second-stage filtration 20412 is arranged between the first-stage filtration 20411 and the coating die 201, and is configured to perform medium filtration on the slurry after the coarse filtration. The third-stage filtration 20413 is arranged between the second-stage filtration 20412 and the coating die 201, and is configured to perform fine filtration on the slurry after the medium filtration.

[0059] It can be understood that the three-stage fine filtration refers to gradually removing impurities in the liquid or gas through three different filtration stages in the filtration process. This multi-stage filtration method can effectively improve the filtration efficiency and ensure the high purity and high quality of the final product. When the slurry passes through the first-stage filtration 20411, coarse filtration is performed on the slurry after the magnetic removal treatment. Generally, the first-stage filtration 20411 uses relatively coarse filter materials (such as filter screens, filter cloths, or large-pore filter cartridges), so that larger particles and suspended solids can be removed, protecting the subsequent filtration equipment and preventing clogging.

[0060] After the slurry passes through the first-stage filtration 20411, it comes to the second-stage filtration 20412. When the slurry passes through the second-stage filtration 20412, medium filtration is performed on the slurry after the coarse filtration. Generally, the second-stage filtration 20412 uses filter cartridges or membrane materials with medium pore sizes, so that medium-sized particles and fine particles can be removed, reducing the impurity content and preparing for the subsequent filtration stage.

[0061] After the slurry passes through the second-stage filtration 20412, it comes to the third-stage filtration 20413. When the slurry passes through the third-stage filtration 20413, fine filtration is performed on the slurry after the medium filtration. Generally, the third-stage filtration 20413 uses high-precision filter cartridges or membrane materials (such as ultrafiltration membranes or nanofiltration membranes), so that extremely fine particles, colloids, or other impurities can be removed, thereby meeting the final high-purity requirement.

[0062] By using three-stage fine filtration to filter the slurry, different-sized particles can be effectively removed through step-by-step filtration, avoiding the possible shortcomings of single-stage filtration. At the same time, the precision of each filtration stage can be adjusted to meet different application requirements. After the first-stage filtration 20411, the second-stage filtration 20412 and the third-stage filtration 20413 can be protected, reducing the risk of clogging and damage. Furthermore, compared with directly using high-precision filtration, three-stage fine filtration can reduce the overall operating cost.

[0063] It can be known that the slurry stored by the storage assembly 203 after the magnetic removal treatment is sequentially filtered by the first-stage filter 20411, the second-stage filter 20412, and the third-stage filter 20413, and the discharge speed is very slow. If the filtered slurry directly enters the die, the slurry entering amount and the slurry entering speed will be affected, the slurry discharging amount and the slurry discharging uniformity will be affected, and the slurry coating uniformity will be affected.

[0064] The material collecting assembly 205 is arranged between the filtering assembly 204 and the coating die 201, and is used to collect the filtered slurry, so as to ensure the slurry entering amount and the slurry entering speed, and to ensure the slurry coating uniformity and to improve the appearance of the electrode sheet 100.

[0065] In some embodiments, referring to FIG. 4, the storage assembly 203 includes two storage tanks 2031, and the two storage tanks 2031 are arranged on the two supply flow paths 202. The storage tank 2031 is arranged to store the slurry after the magnetic removal treatment corresponding to the supply flow path 202. The material collecting assembly 205 includes two material collecting tanks 2051, and the two material collecting tanks 2051 are arranged on the two supply flow paths 202. The material collecting tank 2051 is arranged to collect the filtered slurry corresponding to the supply flow path 202. The capacity of the material collecting tank 2051 is less than the capacity of the storage tank 2031.

[0066] That is, the slurry after the magnetic removal treatment is respectively stored in the two large-capacity storage tanks 2031. The slurry in the storage tank 2031 is filtered by the corresponding filtering part 2041, and is collected in the small-capacity material collecting tank 2051. The slurry in the material collecting tank 2051 is used for material preparation, and is then transported to the coating die 201 and discharged from the corresponding discharge port. In this way, the slurry discharging uniformity can be controlled, so as to ensure the slurry coating uniformity, and to improve the appearance of the electrode sheet 100.

[0067] In an exemplary embodiment, the capacity of the storage tank 2031 is set to 30-50L. It can be known that the storage tank 2031 is used to store the slurry after the magnetic removal treatment. When the capacity of the storage tank 2031 is less than 30L, the capacity of the storage tank 2031 is too small to meet the production demand. When the capacity of the storage tank 2031 is greater than 50L, the capacity of the storage tank 2031 is too large to cause resource waste. The capacity of the storage tank 2031 is set to 30-50L, which can meet the production demand and avoid waste.

[0068] The capacity of the storage tank 2031 is not limited in the present application. The capacity of the storage tank 2031 can be 30L, 35L, 40L, 45L, 50L, or a range formed by any two of them.

[0069] In an exemplary embodiment, the capacity of the collecting tank 2051 is set to 5-15 L; it can be understood that the collecting tank 2051 is set to collect the slurry after the fine filtration treatment, and after the fine filtration, the slurry discharging speed is slow, so the capacity requirement of the collecting tank 2051 is low; when the capacity of the collecting tank 2051 is greater than 15 L, the capacity of the collecting tank 2051 is too large, which will cause resource waste; when the capacity of the collecting tank 2051 is less than 5 L, the capacity of the collecting tank 2051 is too small, which cannot meet the production demand.

[0070] The application does not specifically limit the capacity of the collecting tank 2051. The capacity of the collecting tank 2051 can be 5 L, 8 L, 10 L, 12 L, 15 L or a range formed by any two of them.

[0071] In some embodiments, referring to FIG. 4, the electrode sheet coating device 200 further comprises a dosing assembly 206 and a demagnetization assembly 207; the dosing assembly 206 is separately arranged on the two supply flow paths 202 and is set to configure two kinds of slurry with different proportions; the demagnetization assembly 207 is separately arranged on the two supply flow paths 202 and is between the dosing assembly 206 and the storage assembly 203, and is set to respectively perform demagnetization treatment on the slurry.

[0072] That is, two kinds of slurry with different proportions are configured by the dosing assembly 206, and the two kinds of slurry are respectively transported into the demagnetization assembly 207 for demagnetization treatment, and the two kinds of slurry after the demagnetization treatment are respectively transported into the two storage tanks 2031, and the slurry in the two storage tanks 2031 respectively undergoes fine filtration treatment by the fine filtration part 2041 on the corresponding supply flow path 202, and the slurry after the fine filtration treatment is collected into the corresponding collecting tank 2051 and is uniformly transported to the coating die 201.

[0073] Exemplarily, the dosing assembly 206 comprises two dosing parts 2061, the two dosing parts 2061 are separately arranged on the two supply flow paths 202, and the dosing part 2061 comprises a dosing tank 20611 and a stirring part 20612; the stirring part 20612 is arranged in the dosing tank 20611 and is set to uniformly stir the ingredients in the dosing tank 20611 to form slurry. That is, different proportions of ingredients are respectively placed in the two dosing parts 2061, and the ingredients in the dosing part 2061 are uniformly stirred by the stirring part 20612 to form slurry.

[0074] Exemplarily, the demagnetization assembly 207 includes two demagnetization parts 2071, which are respectively arranged on the two feeding flow paths 202, and the demagnetization part 2071 includes a first-stage demagnetization 20711, a second-stage demagnetization 20712, and a third-stage demagnetization 20713. The first-stage demagnetization 20711 is arranged between the dosing assembly 206 and the storage assembly 203, and is configured to perform first-stage demagnetization on the prepared slurry. The second-stage demagnetization 20712 is arranged between the first-stage demagnetization 20711 and the storage assembly 203, and is configured to perform second-stage demagnetization on the slurry after the first-stage demagnetization. The third-stage demagnetization 20713 is arranged between the second-stage demagnetization 20712 and the storage assembly 203, and is configured to perform third-stage demagnetization on the slurry after the second-stage demagnetization.

[0075] It can be understood that the three-stage demagnetization refers to removing magnetic particles or impurities in liquid, gas or solid through three different stages of demagnetization process. The three-stage demagnetization usually adopts a grading design from low intensity to high intensity of magnetic field, and gradually removes magnetic particles of different particle sizes and different magnetic strengths. The slurry is subjected to first-stage demagnetization by the first-stage demagnetization 20711, and a demagnetization device with a relatively low magnetic field strength (such as a permanent magnet rod or a magnetic grid) is usually used to remove magnetic particles with a relatively large particle size and a strong magnetism, thereby protecting subsequent equipment and preventing clogging or damage.

[0076] The slurry after the first-stage demagnetization is subjected to second-stage demagnetization by the second-stage demagnetization 20712, and a demagnetizer with a relatively high magnetic field strength (such as a gauss magnet rod or a magnetic filter) is usually used to remove magnetic particles with a medium particle size and a medium magnetism, thereby reducing the content of magnetic particles and preparing for fine demagnetization.

[0077] The slurry after the second-stage demagnetization is subjected to third-stage demagnetization by the third-stage demagnetization 20713, and a fine demagnetization device with an ultrahigh magnetic field strength (such as an electromagnetic filter or a superconducting magnetic separator) is usually used to remove magnetic particles with a small particle size and a weak magnetism, thereby achieving the final high-purity requirement.

[0078] The three-stage demagnetization is adopted to perform demagnetization on the prepared slurry, and different particle sizes and different magnetic strengths of magnetic particles can be effectively removed through the three-stage demagnetization. In addition, the parameters of each stage of demagnetization equipment can be adjusted according to the characteristics and requirements of the material, thereby meeting the production requirements and having strong adaptability. Meanwhile, compared with directly using a high magnetic field strength device, the three-stage demagnetization can reduce the overall operation cost. Moreover, the first-stage demagnetization 20711 can protect the second-stage demagnetization 20712 and the third-stage demagnetization 20713, thereby reducing the risk of wear and clogging.

[0079] Exemplarily, the electrode sheet coating device 200 further comprises a coarse filtration assembly 208, the coarse filtration assembly 208 comprises two coarse filtration parts 2081, the two coarse filtration parts 2081 are respectively arranged on the two supply flow paths 202, and the coarse filtration parts 2081 are arranged between the magnetic removal assembly 207 and the storage assembly 203, and are configured to perform coarse filtration on the slurries after the magnetic removal treatment.

[0080] That is, the batching assembly 206 is configured to prepare two slurries with different proportions, and the two slurries are respectively delivered to the two magnetic removal parts 2071 for magnetic removal treatment; the two slurries after the magnetic removal treatment are respectively subjected to coarse filtration treatment by the two coarse filtration parts 2081 to remove larger particles and suspended solids; the two slurries after the coarse filtration treatment are respectively delivered to the two storage tanks 2031, and the slurries in the two storage tanks 2031 are respectively subjected to fine filtration treatment by the fine filtration parts 2041 on the corresponding supply flow paths 202, the slurries after the fine filtration treatment are collected in the corresponding collection tanks 2051, and are uniformly delivered to the coating die 201. The slurry after the magnetic removal treatment is first subjected to coarse filtration treatment by the coarse filtration parts 2081, and then subjected to fine filtration treatment by the fine filtration parts 2041 on the supply flow paths 202, which not only improves the filtration effect, but also protects the subsequent fine filtration parts 2041.

[0081] In some embodiments, referring to FIGS. 5 and 6, the coating die 201 is formed with independent first flow channels 2013 and second flow channels 2014, and the coating die 201 is further formed with a first feeding port 2015 and a second feeding port 2016, the first feeding port 2015 is communicated to the supply flow path 202, the second feeding port 2016 is communicated to the supply flow path 202, the first feeding port 2015 and the first discharging port 2011 are communicated to the first flow channels 2013, and the second feeding port 2016 and the second discharging port 2012 are communicated to the second flow channels 2014.

[0082] That is, two different proportions of slurry are configured by using the ingredient assembly 206, and the two slurries are respectively transported into two demagnetization parts 2071 for demagnetization treatment; the two slurries after demagnetization treatment are respectively subjected to rough filtration treatment through two rough filtration parts 2081 to remove larger particles and suspended solids; the two slurries after rough filtration treatment are respectively transported into two storage tanks 2031, and the slurries in the two storage tanks 2031 are respectively subjected to fine filtration treatment through the fine filtration parts 2041 on the corresponding feed flow paths 202, the slurries after fine filtration treatment are collected into the corresponding material collecting tanks 2051, and are uniformly transported to the coating die 201; one of the slurries is transported from the first feed port 2015 to the first discharge port 2011 through the first flow channel 2013, and is coated on the current collector 1 to form the first electrode coating layer 2; the other of the slurries is transported from the second feed port 2016 to the second discharge port 2012 through the second flow channel 2014, and is coated on the current collector 1 to form the second electrode coating layer 3; thus, the layered coating of the electrode sheet 100 is realized.

[0083] In some embodiments, referring to FIG. 4, the electrode sheet coating device 200 further comprises a feeding assembly 209, and the feeding assembly 209 comprises two feeding pipelines 2091, one of which is arranged at least between the first discharge port 2011, the storage assembly 203, the fine filtration assembly 204 and the material collecting assembly 205 to form one of the feed flow paths 202, and the other of which is arranged at least between the second discharge port 2012, the storage assembly 203, the fine filtration assembly 204 and the material collecting assembly 205 to form the other feed flow path 202.

[0084] That is, the first slurry and the second slurry are respectively configured by using the two ingredient assemblies 2061; the first slurry and the second slurry are transported to the first discharge port 2011 and the second discharge port 2012 after being subjected to demagnetization, rough filtration, fine filtration and collection in sequence through the two feed flow paths 202; the first slurry is sprayed from the first discharge port 2011 to form the first electrode coating layer 2 on the current collector 1, and the second slurry is sprayed from the second discharge port 2012 to form the second electrode coating layer 3 on the current collector 1; at the same time, the single discharge amount of the second discharge port 2012 is controlled to be greater than that of the first discharge port 2011, so that the amount of slurry of the second electrode coating layer 3 is greater than that of the first electrode coating layer 2, and thus the slurry of the second electrode coating layer 3 can form a filling part 32 around the first electrode coating layer 2.

[0085] In a third aspect, based on the electrode sheet 100, the embodiments of the present application further provide an electrode sheet coating method. Referring to FIG. 3, FIG. 3 is a flow chart of the electrode sheet coating method provided by the embodiments of the present application. The electrode sheet coating method comprises:

[0086] S10: providing a current collector 1;

[0087] S20: providing a first slurry and a second slurry;

[0088] S30: coating the first slurry on the first surface 11 of at least one side of the current collector 1;

[0089] S40: drying the current collector 1 coated with the first slurry in a vacuum environment to form a first electrode coating 2 on the current collector 1;

[0090] S50: coating the second slurry on the second surface 21 of the first electrode coating 2, wherein the coating amount of the second slurry is greater than that of the first slurry, so that part of the second slurry flows to the position of the first peripheral side edge 22 of the first electrode coating 2 and forms a filling part 32 on the peripheral side of the first electrode coating 2;

[0091] S60: drying the current collector 1 coated with the second slurry in a vacuum environment to form a second electrode coating 3 on the first electrode coating 2;

[0092] S70: rolling the current collector 1 provided with the first electrode coating 2 and the second electrode coating 3 to form an electrode sheet 100 with a double-layer structure.

[0093] In the present application, the first slurry and the second slurry are coated on the current collector 1 in sequence; by setting the coating amount of the second slurry to be greater than that of the first slurry, part of the second slurry flows to the position of the first peripheral side edge 22 of the first electrode coating 2 and forms a filling part 32 on the peripheral side of the first electrode coating 2; the first slurry and the second slurry are dried respectively to form the first electrode coating 2 and the second electrode coating 3, and finally the first electrode coating 2 and the second electrode coating 3 are rolled to form an electrode sheet 100 with a double-layer structure; the filling part 32 can fill the gap between the first electrode coating 2 and the current collector 1, thereby reducing the segmentation marks at the edges of the first electrode coating 2 and the second electrode coating 3; and the thickness T3 of the filling part 32 is set to be greater than the thickness T1 of the first electrode coating 2, so that the thickness difference ΔT of the electrode coating at the thinning area is less than the thickness T2 of the second electrode coating 3; compared with the related art, the thickness difference at the thinning area position in the present application is smaller, thereby improving the problem of large thickness difference of the electrode coating at the thinning area in the related art.

[0094] In some embodiments, the step S20 of providing the first slurry and the second slurry includes:

[0095] S201: mixing the active material, the conductive agent, and the binder in a first preset ratio to form the first slurry;

[0096] S202: mixing the active material, the conductive agent, and the binder in a second preset ratio to form the second slurry;

[0097] wherein, in the first preset proportion, the mass percentage of the binder is set as X, and in the second preset proportion, the mass percentage of the binder is set as Y, wherein, 。

[0098] In the embodiment, the slurry of the first electrode coating layer 2 comprises an active substance, a conductive agent and a binder; the slurry of the second electrode coating layer 3 comprises an active substance, a conductive agent and a binder; the active substance, the conductive agent and the binder in the slurry of the first electrode coating layer 2 are proportioned in a first preset proportion; and the active substance, the conductive agent and the binder in the slurry of the second electrode coating layer 3 are proportioned in a second preset proportion.

[0099] Meanwhile, the first electrode coating layer 2 is arranged close to the current collector 1, and the second electrode coating layer 3 is arranged away from the current collector 1; by increasing the content of the binder in the first electrode coating layer 2, the mass percentage of the binder in the first electrode coating layer 2 is set to be relatively large, so as to improve the peeling force between the first electrode coating layer 2 and the current collector 1, thereby reducing the resistance of the electrode sheet 100; and the mass percentage of the binder in the second electrode coating layer 3 is set to be relatively small, so that the second electrode coating layer 3 can fill more active substance and conductive agent, thereby improving the cycle performance of the battery.

[0100] Further, after increasing the mass percentage of the binder in the first electrode coating layer 2, the ratio of the mass percentage of the binder in the second electrode coating layer 3 to the mass percentage of the binder in the first electrode coating layer 2 is set to be in the range of 0.2-0.8; when the ratio of the mass percentage of the binder in the second electrode coating layer 3 to the mass percentage of the binder in the first electrode coating layer 2 is greater than 0.8, the mass percentage of the binder in the first electrode coating layer 2 is approximately the same as the mass percentage of the binder in the second electrode coating layer 3, the content of the binder in the first electrode coating layer 2 increases slightly, and the peeling force between the first electrode coating layer 2 and the current collector 1 is not obviously improved; when the ratio of the mass percentage of the binder in the second electrode coating layer 3 to the mass percentage of the binder in the first electrode coating layer 1 is greater than 0.2, the content of the binder in the first electrode coating layer 2 is too large, although the peeling force between the first electrode coating layer 2 and the current collector 1 can be greatly improved, the content of the active substance and the conductive agent in the first electrode coating layer 2 is too small, thereby affecting the cycle performance of the battery.

[0101] In a third aspect, the embodiments of the present application also provide a battery. The battery comprises the electrode sheet 100, and it needs to be explained that the electrode sheet 100 is arranged as the electrode sheet 100, that is, the electrode sheet 100 has all the technical features of the electrode sheet 100, that is, the battery comprises all the embodiments of the electrode sheet 100.

Claims

1. An electrode sheet (100), comprising: current collector(1); A first electrode coating (2) is disposed on at least one side of the first surface (11) of the current collector (1); as well as, The second electrode coating (3) is stacked on the first surface (11) of the first electrode coating (2) on the side away from the current collector (1). The second peripheral edge (31) of the second electrode coating (3) extends beyond the first peripheral edge (22) of the first electrode coating (2), and the extended portion is arranged around the outer peripheral side of the first electrode coating (2). A filling portion (32) is formed on the outer peripheral side of the first electrode coating (2). In the stacking direction of the first electrode coating (2) and the second electrode coating (3), the thickness of the filling portion (32) is greater than the thickness of the first electrode coating (2).

2. The electrode sheet (100) according to claim 1, wherein, In the stacking direction of the first electrode coating (2) and the second electrode coating (3), the thickness of the filling portion (32) is equal to the sum of the thickness of the first electrode coating (2) and the thickness of the second electrode coating (3).

3. The electrode sheet (100) according to claim 1 or 2, wherein, The slurry of the first electrode coating (2) includes an active substance, a conductive agent, and a binder; The slurry of the second electrode coating (3) includes active material, conductive agent and binder; The mass percentage of the binder in the first electrode coating (2) is set as X, and the mass percentage of the binder in the second electrode coating (3) is set as Y, where .

4. The electrode sheet (100) according to any one of claims 1 to 3, wherein, In the stacking direction of the first electrode coating (2) and the second electrode coating (3), the thickness of the first electrode coating (2) and the second electrode coating (3) is the same.

5. The electrode sheet (100) according to any one of claims 1 to 4, wherein, In the direction away from the first peripheral edge (22) of the first electrode coating (2), the width of the filling portion (32) is set to W, where 0.1mm≤W≤0.5mm.

6. The electrode sheet (100) according to any one of claims 1 to 5, wherein, In the stacking direction of the first electrode coating (2) and the second electrode coating (3), the thickness of the first electrode coating (2) is set to T1, the thickness of the second electrode coating (3) is set to T2, and the thickness of the filling part (32) is set to T3, wherein 0≤(T1+T2)-T3≤9μm.

7. The electrode sheet (100) according to any one of claims 2-6, wherein, The current collector (1) is set as aluminum foil or copper foil.

8. A coating apparatus (200) for an electrode sheet as described in any one of claims 1 to 7, comprising a coating die (201) and at least two feed paths (202), wherein the coating die (201) has a first outlet (2011) and a second outlet (2012) configured to spray slurry toward a current collector (1) respectively, the first outlet (2011) being connected to one of the feed paths (202) and the second outlet (2012) being connected to the other feed path (202); The electrode coating apparatus (200) further includes: The storage component (203) is disposed on the two feeding paths (202) and is configured to store the slurry after demagnetization treatment; The fine filtration component (204) is disposed on the two feeding flow paths (202) and located between the material storage component (203) and the coating die head (201), and is configured to perform fine filtration on the demagnetized slurry; as well as, The material collection assembly (205) is disposed on the two material supply paths (202) and located between the fine filtration assembly (204) and the coating die head (201), and is configured to collect the slurry after fine filtration.

9. The coating apparatus (200) for the electrode sheet according to claim 8, wherein, The fine filtration assembly (204) includes two fine filtration sections (2041), which are respectively disposed on the two feed paths (202). Each fine filtration section (2041) includes: The first-stage filter (20411) is located between the material storage assembly (203) and the coating die head (201) and is configured to perform coarse filtration on the demagnetized slurry. A second-stage filter (20412) is disposed between the first-stage filter (20411) and the coating die (201), and is configured to perform a medium-stage filtration treatment on the slurry after coarse filtration; and, The third-stage filter (20413) is located between the second-stage filter (20412) and the coating die (201) and is configured to perform fine filtration on the slurry after intermediate filtration.

10. The coating apparatus (200) for the electrode sheet according to claim 8 or 9, wherein, The storage component (203) includes two storage tanks (2031), which are respectively located on two feeding paths (202). The storage tanks (2031) are configured to store the demagnetized slurry on the corresponding feeding path (202). The collecting assembly (205) includes two collecting tanks (2051), which are respectively located on two feeding paths (202). The collecting tanks (2051) are configured to collect the finely filtered slurry on the corresponding feeding path (202). The capacity of the collection tank (2051) is smaller than that of the storage tank (2031).

11. The electrode coating apparatus (200) according to claim 10, wherein, The capacity of the storage tank (2031) is set to 30~50L; The capacity of the collection tank (2051) is set to 5~15L.

12. The electrode coating apparatus (200) according to any one of claims 8 to 11, wherein the electrode coating apparatus (200) further comprises: The batching components (206) are respectively disposed on the two feeding flow paths (202) and are configured to prepare two slurries with different proportions; The demagnetizing component (207) is disposed on the two feeding paths (202) and located between the dispensing component (206) and the storage component (203), and is configured to demagnetize the slurry respectively.

13. The electrode coating apparatus (200) according to claim 12, wherein, The dispensing assembly (206) includes two dispensing sections (2061), which are respectively disposed on the two feeding paths (202). Each dispensing section (2061) includes: Ingredient tank (20611); and, A stirring unit (20612) is provided inside the mixing tank (20611) and is configured to stir the ingredients in the mixing tank (20611) evenly to form a slurry.

14. The coating apparatus (200) for the electrode sheet according to claim 12 or 13, wherein, The demagnetizing assembly (207) includes two demagnetizing sections (2071), which are respectively disposed on the two feeding paths (202). Each demagnetizing section (2071) includes: The first-stage demagnetization (20711) is located between the batching component (206) and the storage component (203) and is configured to perform the first demagnetization treatment on the prepared slurry. The second-stage demagnetization (20712) is disposed between the first-stage demagnetization (20711) and the storage assembly (203), and is configured to perform a second demagnetization treatment on the slurry after the first demagnetization treatment; and, The third-stage demagnetization (20713) is located between the second-stage demagnetization (20712) and the storage component (203), and is configured to perform a third demagnetization treatment on the slurry after the second demagnetization treatment.

15. The electrode coating apparatus (200) according to any one of claims 12 to 14, wherein the electrode coating apparatus (200) further comprises a coarse filtration assembly (208), the coarse filtration assembly (208) comprising two coarse filtration sections (2081), the two coarse filtration sections (2081) being disposed on two feed paths (202), the coarse filtration sections (2081) being located between the demagnetizing assembly (207) and the storage assembly (203), and being configured to perform coarse filtration on the demagnetized slurry.

16. The coating apparatus (200) for an electrode sheet according to any one of claims 8 to 15, wherein, The coating die (201) has an independent first flow channel (2013) and a second flow channel (2014). The coating die (201) also has a first feed port (2015) and a second feed port (2016). The first feed port (2015) is connected to the material supply path (202), and the second feed port (2016) is connected to the material supply path (202). The first feed port (2015) and the first discharge port (2011) are connected to the first flow channel (2013), and the second feed port (2016) and the second discharge port (2012) are connected to the second flow channel (2014).

17. The electrode coating apparatus (200) according to any one of claims 9 to 16, the electrode coating apparatus (200) further comprising a feeding assembly (209), the feeding assembly (209) comprising two feeding pipes (2091), one of the feeding pipes (2091) being at least disposed between the first outlet (2011), the storage assembly (203), the fine filtration assembly (204) and the collecting assembly (205) to form one of the feeding flow paths (202), and the other feeding pipe (2091) being at least disposed between the second outlet (2012), the storage assembly (203), the fine filtration assembly (204) and the collecting assembly (205) to form another feeding flow path (202).

18. A coating method for an electrode sheet (100) according to any one of claims 1-7, the coating method for the electrode sheet (100) comprising: Provide a current collector (1); Provide first and second slurries; The first slurry is coated on at least one side of the first surface (11) of the current collector (1); The current collector (1) coated with the first slurry is placed in a vacuum environment for drying to form a first electrode coating (2) on the current collector (1); The second slurry is coated on the second surface (21) of the first electrode coating (2), wherein the coating amount of the second slurry is greater than the coating amount of the first slurry, so that a portion of the second slurry flows to the first peripheral edge (22) of the first electrode coating (2) and forms a filling portion (32) on the peripheral side of the first electrode coating (2). The current collector (1) coated with the second slurry is dried in a vacuum environment to form a second electrode coating (3) on the first electrode coating (2); The current collector (1), which is provided with the first electrode coating (2) and the second electrode coating (3) in layers, is rolled to form an electrode sheet (100) with a double-layer structure.

19. The coating method for the electrode sheet (100) according to claim 18, wherein, The step of providing the first slurry and the second slurry includes: The active material, conductive agent, and binder are mixed in a first preset ratio to form the first slurry; The active material, conductive agent, and binder are mixed in a second preset ratio to form the second slurry; In the first preset ratio, the mass percentage of the adhesive is set as X, and in the second preset ratio, the mass percentage of the adhesive is set as Y.

20. A battery comprising an electrode sheet (100) as described in any one of claims 1-7.

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