Electrode plate coating device

Abstract

The utility model provides an electrode plate coating device which comprises a coating die head and at least two feeding flow paths, a first discharge port and a second discharge port are formed in the coating die head and used for spraying slurry towards a current collector respectively, the first discharge port is communicated with one feeding flow path, and the second discharge port is communicated with the other feeding flow path. The second material outlet is communicated with the other material supply flow path; the electrode plate coating device further comprises a material storage assembly, a fine filtration assembly and a material collection assembly. The material storage assemblies are arranged on the two material supply flow paths correspondingly and used for storing demagnetized slurry. The fine filtration assemblies are separately arranged on the two feeding flow paths, are located between the material storage assembly and the coating die head and are used for performing fine filtration treatment on the demagnetized slurry; the material collecting assemblies are separately arranged on the two material supply flow paths, are positioned between the fine filtration assembly and the coating die head, and are used for collecting slurry subjected to fine filtration treatment; therefore, the impurity content can be reduced, so that the problem of poor appearance caused by particle scratches on the coating of the electrode plate in the layered thin coating process is solved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery manufacturing technology, specifically to an electrode sheet coating device. Background Technology

[0002] In the production process of lithium batteries, the manufacturing of electrode sheets plays a crucial role. Statistics show that approximately 70% of lithium battery quality problems are 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 residual adhesive and make the electrode sheets prone to detachment, a layered coating method is often used. However, in commonly used coating equipment, the electrode sheet coating may exhibit particle scratches and other aesthetic defects during the thin-layer coating process. Utility Model Content

[0003] The present invention provides an electrode coating apparatus that can improve the technical problem of poor appearance of electrode coating with particle scratches during the layered thin coating process of commonly used coating apparatuses.

[0004] In a first aspect, an embodiment of the present invention provides an electrode sheet coating device, including a coating die head and at least two material supply channels. The coating die head has a first outlet and a second outlet for spraying slurry toward a current collector, respectively. The first outlet is connected to one of the material supply channels, and the second outlet is connected to the other material supply channel.

[0005] The electrode coating apparatus further includes:

[0006] The storage components are located on the two feed paths and are used to store the demagnetized slurry.

[0007] A fine filtration assembly, disposed on both of the aforementioned feed paths and located between the storage assembly and the coating die, is used to perform fine filtration on the demagnetized slurry; and,

[0008] The material collection assembly is disposed on both of the material supply paths and is located between the fine filtration assembly and the coating die head, and is used to collect the slurry after fine filtration.

[0009] In one embodiment, the fine filtration assembly includes two fine filtration sections, which are respectively disposed on two feed flow paths. Each fine filtration section includes:

[0010] The first-stage filter is located between the material storage assembly and the coating die head, and is used to perform coarse filtration on the slurry after demagnetization.

[0011] A second-stage filter, positioned between the first-stage filter and the coating die, is used for intermediate filtration of the slurry after coarse filtration; and...

[0012] The third-stage filter is located between the second-stage filter and the coating die head, and is used to perform fine filtration on the slurry after the intermediate filtration.

[0013] In one embodiment, the storage assembly includes two storage tanks, which are respectively disposed on two feeding paths. The storage tanks are used to store the demagnetized slurry on the corresponding feeding path.

[0014] The material collection assembly includes two material collection tanks, which are respectively located on two material supply paths. The material collection tanks are used to collect the finely filtered slurry on the corresponding material supply path.

[0015] The capacity of the collection tank is smaller than the capacity of the storage tank.

[0016] In one embodiment, the capacity of the storage tank is set to 30-50L;

[0017] The capacity of the collection tank is set to 5-15L.

[0018] In one embodiment, the electrode coating apparatus further includes:

[0019] The batching components are located on the two feed paths and are used to prepare two slurries with different proportions.

[0020] The demagnetizing components are separately located on the two feed flow paths and between the batching component and the storage component, and are used to demagnetize the slurry respectively.

[0021] In one embodiment, the dispensing assembly includes two dispensing sections disposed on two feed paths, each dispensing section comprising:

[0022] Ingredient tanks; and,

[0023] A stirring section is provided inside the mixing tank to stir the ingredients in the mixing tank evenly to form a slurry.

[0024] In one embodiment, the demagnetizing assembly includes two demagnetizing sections disposed on two feed paths, each demagnetizing section comprising:

[0025] The first-stage demagnetization is located between the batching component and the storage component, and is used to perform the first demagnetization treatment on the prepared slurry.

[0026] A second-stage demagnetization process, positioned between the first-stage demagnetization and the storage assembly, is used to perform a second demagnetization treatment on the slurry after the first demagnetization process; and...

[0027] The third-stage demagnetization is located between the second-stage demagnetization and the storage assembly, and is used to perform a third demagnetization on the slurry after the second demagnetization treatment.

[0028] In one embodiment, the electrode coating apparatus further includes a coarse filtration assembly, which includes two coarse filtration sections disposed on the two feed flow paths. The coarse filtration sections are located between the demagnetizing assembly and the storage assembly, and are used to perform coarse filtration on the slurry after demagnetization.

[0029] In one embodiment, the coating die head has an independent first flow channel and a second flow channel. The coating die head also has a first feed port and a second feed port. The first feed port is connected to the material supply flow path, and the second feed port is connected to the material supply flow path. The first feed port and the first discharge port are connected to the first flow channel, and the second feed port and the second discharge port are connected to the second flow channel.

[0030] In one embodiment, the electrode coating apparatus further includes a feeding assembly, which includes two feeding pipes. One feeding pipe is at least disposed between the first outlet, the storage assembly, the fine filtration assembly, and the collection assembly to form one of the feeding paths. The other feeding pipe is at least disposed between the second outlet, the storage assembly, the fine filtration assembly, and the collection assembly to form another feeding path.

[0031] The beneficial effects of the embodiments of this utility model are as follows:

[0032] In an embodiment of this invention, the electrode coating apparatus includes a coating die and at least two feeding paths. A first outlet and a second outlet on the coating die are used to spray slurry into the current collector, respectively. The first outlet and the second outlet are connected to the two feeding paths. In each feeding path, the demagnetized slurry is stored in a storage component. Before being delivered to the corresponding outlet on the coating die, the slurry undergoes fine filtration through a fine filtration component to remove micron- or even submicron-sized particles, significantly reducing impurity content and improving the appearance defects of particle scratches on the electrode coating during the thin-layer coating process. Simultaneously, the slurry discharges slowly after fine filtration. A collecting component is installed between the fine filtration component and the coating die to collect the finely filtered slurry, ensuring the slurry feed rate and feed speed, thereby ensuring uniform slurry coating and further improving the appearance defects of the electrode coating. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a simplified structural diagram of the electrode sheet coating device provided in an embodiment of this utility model;

[0035] Figure 2 This is a schematic diagram of the structure of the electrode coating die provided in an embodiment of the present invention;

[0036] Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the image;

[0037] Figure 4 This is a flowchart of the electrode sheet coating method provided in an embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of the electrode sheet coating provided in an embodiment of this utility model.

[0039] The names of the components corresponding to the corresponding reference numerals in the figure are:

[0040] 100 electrode coating apparatus;

[0041] 1 Coating die head; 11 First discharge port; 12 Second discharge port; 13 First flow channel; 14 Second flow channel; 15 First feed port; 16 Second feed port;

[0042] 2. Material feeding path;

[0043] 3. Material storage components; 31. Material storage tanks;

[0044] 4. Fine filtration assembly; 41. Fine filtration section; 411. First-stage filtration; 412. Second-stage filtration; 413. Third-stage filtration;

[0045] 5. Aggregator assembly; 51. Aggregator hopper;

[0046] 6. Batching assembly; 61. Batching section; 611. Batching tank; 612. Mixing section;

[0047] 7. Demagnetizing assembly; 71. Demagnetizing section; 711. First-stage demagnetization; 712. Second-stage demagnetization; 713. Third-stage demagnetization;

[0048] 8. Coarse filtration assembly; 81. Coarse filtration section;

[0049] 9. Feeding assembly; 91. Feeding pipeline;

[0050] 200 Electrode sheet; 201 Current collector; 2011 Surface; 202 First electrode coating; 2021 Surface; 2022 Peripheral edge; 203 Second electrode coating; 2031 Peripheral edge; 2032 Filler portion. Detailed Implementation

[0051] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0052] In a first aspect, this utility model provides an electrode coating apparatus 100. (See also...) Figures 1 to 3 The electrode coating apparatus 100 includes a coating die 1 and at least two feed paths 2. The coating die 1 has a first outlet 11 and a second outlet 12 for spraying slurry into the current collector 201, respectively. The first outlet 11 is connected to one of the feed paths 2, and the second outlet 12 is connected to the other feed path 2. The electrode coating apparatus 100 also includes a storage component 3, a fine filtration component 4, and a collection component 5. The storage component 3 is disposed on the two feed paths 2 and is used to store the slurry after demagnetization treatment. The fine filtration component 4 is disposed on the two feed paths 2 and is located between the storage component 3 and the coating die 1, and is used to perform fine filtration treatment on the slurry after demagnetization treatment. The collection component 5 is disposed on the two feed paths 2 and is located between the fine filtration component 4 and the coating die 1, and is used to collect the slurry after fine filtration treatment.

[0053] In an embodiment of this utility model, the electrode sheet coating device 100 includes a coating die head 1 and two feeding channels 2. The first outlet 11 and the second outlet 12 on the coating die head 1 are used to spray slurry into the current collector 201, respectively. The first outlet 11 and the second outlet 12 are respectively connected to the two feeding channels 2. On each feeding channel 2, the demagnetized slurry is stored in the storage component 3. Before the slurry is conveyed to the corresponding outlet on the coating die head 1, it will be filtered by the fine filter component 4 to remove micron or even submicron particles in the slurry, which can significantly reduce the impurity content and improve the appearance problem of particle scratches on the coating of the electrode sheet 200 during the layered thin coating process. At the same time, the slurry is discharged slowly after fine filtration. A collecting component 5 is set between the fine filter component 4 and the coating die head 1 to collect the finely filtered slurry, thereby ensuring the amount and speed of slurry entering the die, and thus ensuring uniform slurry coating, further improving the appearance problem of the coating of the electrode sheet 200.

[0054] In one embodiment, please refer to Figure 1 The fine filtration assembly 4 includes two fine filtration sections 41, which are respectively disposed on the two feed paths 2. Each fine filtration section 41 includes a first-stage filter 411, a second-stage filter 412, and a third-stage filter 413. The first-stage filter 411 is disposed between the material storage assembly 3 and the coating die head 1 and is used to perform coarse filtration on the demagnetized slurry. The second-stage filter 412 is disposed between the first-stage filter 411 and the coating die head 1 and is used to perform medium filtration on the coarsely filtered slurry. The third-stage filter 413 is disposed between the second-stage filter 412 and the coating die head 1 and is used to perform fine filtration on the medium-filtered slurry.

[0055] It is understood that three-stage fine filtration refers to the process of gradually removing impurities from liquids or gases through three filtration stages with different levels of precision. This multi-stage filtration method can effectively improve filtration efficiency and ensure the high purity and quality of the final product. When the slurry passes through the first-stage filter 411, the demagnetized slurry undergoes coarse filtration. Typically, the first-stage filter 411 uses coarser filter materials (such as filter screens, filter cloths, or large-pore filter cartridges) to remove larger particles and suspended solids, protecting subsequent filtration equipment and preventing clogging.

[0056] After passing through the first stage filtration 411, the slurry enters the second stage filtration 412. When passing through the second stage filtration 412, the slurry after coarse filtration undergoes medium filtration. Typically, the second stage filtration 412 uses a filter element or membrane material with a medium pore size. In this way, medium-sized particles and microparticles can be removed, further reducing the impurity content and preparing for subsequent filtration stages.

[0057] After passing through the second-stage filtration 412, the slurry enters the third-stage filtration 413. When passing through the third-stage filtration 413, the slurry after the medium filtration treatment undergoes fine filtration. Typically, the third-stage filtration 413 uses a high-precision filter element or membrane material (such as an ultrafiltration membrane or nanofiltration membrane). In this way, extremely fine particles, colloids, or other impurities can be removed, thereby achieving the final high purity requirement.

[0058] By employing a three-stage fine filtration system to filter the slurry, particles of different sizes can be effectively removed through step-by-step filtration, avoiding the shortcomings that may exist in single-stage filtration. At the same time, the precision of each stage of filtration can be adjusted to meet different application requirements. Furthermore, after passing through the first stage filter 411, the second stage filter 412 and the third stage filter 413 can be protected, reducing the risk of clogging and damage. Moreover, compared to directly using high-precision filtration, three-stage fine filtration can reduce overall operating costs.

[0059] It is known that the demagnetized slurry stored in the storage component 3 will have a very slow discharge speed after passing through the first-stage filter 411, the second-stage filter 412, and the third-stage filter 413. If the finely filtered slurry is directly fed into the mold, it will affect the amount and speed of the slurry fed into the mold, thereby affecting the amount and uniformity of the slurry discharged from the mold, and thus causing uneven slurry coating.

[0060] By setting the material collection component 5 between the fine filtration component 4 and the coating die head 1, the slurry after fine filtration is collected, thereby ensuring the amount and speed of slurry entering the die, thus ensuring uniform slurry coating and further improving the appearance defects of the electrode sheet 200 coating.

[0061] In one embodiment, please refer to Figure 1 The storage component 3 includes two storage tanks 31, which are respectively disposed on the two feeding paths 2. The storage tanks 31 are used to store the slurry after demagnetization treatment on the corresponding feeding path 2. The collection component 5 includes two collection tanks 51, which are respectively disposed on the two feeding paths 2. The collection tanks 51 are used to collect the slurry after filtration treatment on the corresponding feeding path 2. The capacity of the collection tanks 51 is smaller than the capacity of the storage tanks 31.

[0062] In other words, the slurry after demagnetization is stored in two large-capacity storage tanks 31. After being finely filtered by the corresponding fine filtration section 41, the slurry in the storage tanks 31 is collected in the small-capacity collection tank 51 for slurry preparation. The slurry in the collection tank 51 is then transported to the coating die head 1 and discharged from the corresponding outlet. In this way, the uniformity of slurry discharge can be controlled, thereby ensuring uniform slurry coating and further improving the appearance defects of the electrode sheet 200 coating.

[0063] In an exemplary embodiment, the capacity of the storage tank 31 is set to 30-50L. It is understood that the storage tank 31 is used to store the slurry after demagnetization treatment. When the capacity of the storage tank 31 is less than 30L, the capacity is too small to meet production needs; when the capacity of the storage tank 31 is greater than 50L, the capacity is too large, resulting in resource waste. Setting the capacity of the storage tank 31 to 30-50L ensures production needs are met without causing waste.

[0064] This application does not impose a specific limitation on the capacity of the storage tank 31. The capacity of the storage tank 31 can be 30L, 35L, 40L, 45L, 50L, or any combination thereof.

[0065] In an exemplary embodiment, the capacity of the collection tank 51 is set to 5-15L. It is understood that the collection tank 51 is used to collect the slurry after fine filtration. After fine filtration, the slurry discharge rate slows down, so the capacity requirement of the collection tank 51 is relatively low. When the capacity of the collection tank 51 is greater than 15L, the capacity of the collection tank 51 is too large, which will cause waste of resources. When the capacity of the collection tank 51 is less than 5L, the capacity of the collection tank 51 is too small and cannot meet the production needs.

[0066] This application does not impose a specific limitation on the capacity of the collection tank 51. The capacity of the collection tank 51 can be a range of 5L, 8L, 10L, 12L, 15L, or any combination thereof.

[0067] In one embodiment, please refer to Figure 1 The electrode coating device 100 further includes a dispensing component 6 and a demagnetizing component 7; the dispensing component 6 is disposed on two of the feeding flow paths 2 and is used to prepare two slurries with different proportions; the demagnetizing component 7 is disposed on two of the feeding flow paths 2 and is located between the dispensing component 6 and the storage component 3, and is used to demagnetize the slurries respectively.

[0068] In other words, two slurries with different ratios are prepared using the mixing component 6, and the two slurries are respectively transported to the demagnetizing component 7 for demagnetization treatment. The two slurries after demagnetization treatment are respectively transported to the two storage tanks 31. The slurries in the two storage tanks 31 are respectively subjected to fine filtration treatment through the fine filtration section 41 on the corresponding feed flow path 2. The finely filtered slurries are collected in the corresponding collection tank 51 and are evenly transported to the coating die head 1.

[0069] Specifically, the ingredient preparation assembly 6 includes two ingredient preparation sections 61, which are respectively disposed on the two material supply paths 2. Each ingredient preparation section 61 includes an ingredient tank 611 and a stirring section 612. The stirring section 612 is disposed inside the ingredient tank 611 and is used to stir the ingredients in the ingredient tank 611 evenly to form a slurry. That is, ingredients with different proportions are placed in the two ingredient preparation sections 61 respectively, and the stirring section 612 is used to stir the ingredients in the ingredient preparation section 61 evenly to form a slurry.

[0070] Specifically, the demagnetizing assembly 7 includes two demagnetizing sections 71, which are respectively disposed on the two feeding paths 2. Each demagnetizing section 71 includes a first-stage demagnetization 711, a second-stage demagnetization 712, and a third-stage demagnetization 713. The first-stage demagnetization 711 is disposed between the batching assembly 6 and the storage assembly 3, and is used to perform a first demagnetization treatment on the prepared slurry. The second-stage demagnetization 712 is disposed between the first-stage demagnetization 711 and the storage assembly 3, and is used to perform a second demagnetization treatment on the slurry after the first demagnetization treatment. The third-stage demagnetization 713 is disposed between the second-stage demagnetization 712 and the storage assembly 3, and is used to perform a third demagnetization treatment on the slurry after the second demagnetization treatment.

[0071] It is understood that three-stage demagnetization refers to the gradual removal of magnetic particles or impurities from liquids, gases, or solids through three different stages of demagnetization processes. Three-stage demagnetization typically employs a graded design of magnetic fields from low to high intensity, removing magnetic particles of different sizes and magnetic strengths step by step. The slurry undergoes its first demagnetization treatment (711), usually using a lower magnetic field strength demagnetizing device (such as a permanent magnet rod or magnetic grid) to remove larger, strongly magnetic particles, protecting subsequent equipment and preventing blockage or damage.

[0072] The slurry that has undergone the first demagnetization treatment goes through the second stage demagnetization 712 for a second demagnetization treatment. Usually, a demagnetizer with a higher magnetic field strength (such as a Gaussian magnetic rod or magnetic filter) is used to remove medium-sized particles with medium magnetic properties, further reducing the content of magnetic particles and preparing for fine demagnetization.

[0073] The slurry that has undergone the second demagnetization process is then subjected to a third demagnetization process using the third-stage demagnetization 713. This process typically employs a precision demagnetization device with ultra-high magnetic field strength (such as an electromagnetic filter or a superconducting magnetic separator) to remove small-diameter and weakly magnetic particles, thereby achieving the final high-purity requirement.

[0074] A three-stage demagnetization process is used to demagnetize the prepared slurry. Through step-by-step demagnetization, magnetic particles of different sizes and magnetic strengths can be effectively removed. Furthermore, the parameters of each stage of the demagnetization equipment can be adjusted according to the material characteristics and requirements to meet production requirements, demonstrating strong adaptability. At the same time, compared with directly using high magnetic field strength equipment, three-stage demagnetization can reduce overall operating costs. Moreover, the first-stage demagnetization 711 can protect the second-stage demagnetization 712 and the third-stage demagnetization 713, reducing the risk of wear and blockage.

[0075] Specifically, the electrode coating device 100 further includes a coarse filtration assembly 8, which includes two coarse filtration sections 81. The two coarse filtration sections 81 are respectively disposed on the two feed flow paths 2. The coarse filtration sections 81 are located between the demagnetizing assembly 7 and the storage assembly 3, and are used to perform coarse filtration on the slurry after demagnetization.

[0076] In other words, the mixing component 6 is used to prepare two slurries with different proportions, and the two slurries are respectively fed into the two demagnetizing sections 71 for demagnetization treatment. After demagnetization, the two slurries are respectively subjected to coarse filtration treatment in the two coarse filtration sections 81 to remove larger particles and suspended solids. After coarse filtration, the two slurries are respectively fed into the two storage tanks 31, and the slurries in the two storage tanks 31 are respectively subjected to fine filtration treatment in the corresponding fine filtration sections 41 on the corresponding feed flow path 2. The finely filtered slurries are collected in the corresponding collection tanks 51 and then evenly fed to the coating die head 1. The fact that the demagnetized slurry is first subjected to coarse filtration treatment in the coarse filtration section 81 and then to fine filtration treatment in the fine filtration section 41 on the feed flow path 2 not only improves the filtration effect, but also protects the subsequent fine filtration section 41.

[0077] In one embodiment, please refer to Figure 2 and Figure 3 The coating die head 1 has an independent first flow channel 13 and a second flow channel 14. The coating die head 1 also has a first feed port 15 and a second feed port 16. The first feed port 15 is connected to the material supply flow path 2, and the second feed port 16 is connected to the material supply flow path 2. The first feed port 15 and the first discharge port 11 are connected to the first flow channel 13, and the second feed port 16 and the second discharge port 12 are connected to the second flow channel 14.

[0078] In other words, the mixing component 6 is used to prepare two slurries with different proportions, and the two slurries are respectively transported to the two demagnetizing sections 71 for demagnetization treatment; after demagnetization treatment, the two slurries are respectively subjected to coarse filtration treatment by the two coarse filtration sections 81 to remove larger particles and suspended solids; after coarse filtration treatment, the two slurries are respectively transported to the two storage tanks 31, and the slurries in the two storage tanks 31 are respectively subjected to fine filtration treatment by the fine filtration sections 41 on the corresponding feed flow path 2; the slurries after fine filtration treatment are collected. The corresponding material is collected in the collection tank 51 and uniformly conveyed to the coating die head 1; one type of slurry is conveyed from the first inlet 15, through the first flow channel 13, to the first outlet 11, and coated on the current collector 201 to form a first electrode coating 202; another type of slurry is conveyed from the second inlet 16, through the second flow channel 14, to the second outlet 12, and coated on the current collector 201 to form a second electrode coating 203; thus, the layered coating of the electrode sheet 200 is achieved.

[0079] In one embodiment, please refer to Figure 1 The electrode coating apparatus 100 further includes a feeding assembly 9, which includes two feeding pipes 91. One feeding pipe 91 is at least disposed between the first outlet 11, the storage assembly 3, the fine filtration assembly 4, and the collection assembly 5 to form one of the feeding flow paths 2. The other feeding pipe 91 is at least disposed between the second outlet 12, the storage assembly 3, the fine filtration assembly 4, and the collection assembly 5 to form another feeding flow path 2.

[0080] Based on the electrode coating apparatus 100 described above, this application also provides an electrode coating method. Please refer to... Figure 4 , Figure 4 This is a flowchart of an electrode sheet coating method provided in an embodiment of the present invention. The coating method for the electrode sheet 200 includes:

[0081] S10: Provides a current collector 201;

[0082] S20: Provides the first and second slurries;

[0083] S30: The first slurry is coated on at least one side surface 2011 of the current collector 201;

[0084] S40: The current collector 201 coated with the first slurry is placed in a vacuum environment for drying to form a first electrode coating 202 on the current collector 201.

[0085] S50: The second slurry is coated on the surface 2021 of the first electrode coating 202, 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 peripheral edge 2022 of the first electrode coating 202 and forms a filling portion 2032 on the peripheral side of the first electrode coating 202.

[0086] S60: The current collector 201 coated with the second slurry is placed in a vacuum environment for drying to form a second electrode coating 203 on the first electrode coating 202;

[0087] S70: The current collector 201, which is provided with the first electrode coating 202 and the second electrode coating 203, is rolled to form an electrode sheet 200 with a double-layer structure.

[0088] In this application, the first slurry and the second slurry are sequentially coated on the current collector 201; by setting the coating amount of the second slurry to be greater than that of the first slurry, a portion of the second slurry flows to the peripheral edge 2022 of the first electrode coating 202, forming a filling portion 2032 on the periphery of the first electrode coating 202; the first slurry and the second slurry are dried respectively to form the first electrode coating 202 and the second electrode coating 203; finally, the first electrode coating 202 and the second electrode coating 203 are rolled to form a double-layer structure. The electrode sheet 200; the leveling portion 2032 can fill the step difference between the first electrode coating 202 and the current collector 201, thereby reducing the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203; and, the thickness T3 of the leveling portion 2032 is set to be greater than the thickness T1 of the first electrode coating 202, so the thickness difference ΔT of the electrode coating in the thinning area is less than the thickness T2 of the second electrode coating 203; compared with the related technology, the thickness difference at the thinning area is smaller in the present invention, thereby improving the problem of large thickness difference of the electrode coating in the thinning area in the related technology.

[0089] In one embodiment, step S20 of providing the first slurry and the second slurry includes:

[0090] S201: The active material, conductive agent and binder are mixed in a first preset ratio to form the first slurry;

[0091] S202: The active material, conductive agent and binder are mixed in a second preset ratio to form the second slurry;

[0092] In the first preset ratio, the mass percentage of the adhesive is set as X; in the second preset ratio, the mass percentage of the adhesive is set as Y.

[0093] In this embodiment, the first slurry and the second slurry are respectively prepared using two mixing units 61. The first slurry includes an active substance, a conductive agent, and a binder; the second slurry includes an active substance, a conductive agent, and a binder; the active substance, conductive agent, and binder in the first slurry are mixed in a first preset ratio; the active substance, conductive agent, and binder in the second slurry are mixed in a second preset ratio.

[0094] Meanwhile, the first electrode coating 202 is disposed close to the current collector 201, and the second electrode coating 203 is disposed away from the current collector 201. By increasing the binder content in the first electrode coating 202 and setting the mass percentage of binder in the first electrode coating 202 to be larger, the peel force between the first electrode coating 202 and the current collector 201 can be improved, thereby reducing the resistance of the electrode sheet 200. Furthermore, by setting the mass percentage of binder in the second electrode coating 203 to be smaller, the second electrode coating 203 can be filled with more active material and conductive agent, thereby improving the cycle performance of the battery.

[0095] Furthermore, after increasing the mass percentage of the binder in the first electrode coating 202, the ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202 is set to a range of 0.2 to 0.8. When the ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202 is greater than 0.8, the mass percentage of the binder in the first electrode coating 202 is approximately the same as the mass percentage of the binder in the second electrode coating 203. The increase in binder content in the first electrode coating 202 is small, and the peel force between the first electrode coating 202 and the current collector 201 is not significantly improved. When the ratio of the mass percentage of binder in the second electrode coating 203 to the mass percentage of binder in the first electrode coating 202 is greater than 0.2, the binder content in the first electrode coating 202 is too large. Although it can significantly improve the peel force between the first electrode coating 202 and the current collector 201, the content of active material and conductive agent in the first electrode coating 202 is too small, which will affect the cycle performance of the battery.

[0096] Based on the above-described electrode coating method, this application also provides an electrode sheet 200. Please refer to... Figure 5 , Figure 5This is a schematic diagram of the structure of the electrode sheet 200 coating provided in an embodiment of the present invention.

[0097] The electrode sheet 200 includes a current collector 201, a first electrode coating 202, and a second electrode coating 203. The first electrode coating 202 is disposed on at least one side surface 2011 of the current collector 201. The second electrode coating 203 is stacked on the side surface 2011 of the first electrode coating 202 facing away from the current collector 201. The peripheral edge 2031 of the second electrode coating 203 extends beyond the peripheral edge 2022 of the first electrode coating 202, and the extended portion surrounds the outer periphery of the first electrode coating 202, forming a filling portion 2032 on the outer periphery of the first electrode coating 202. In the stacking direction of the first electrode coating 202 and the second electrode coating 203, the thickness of the filling portion 2032 is greater than the thickness of the first electrode coating 202.

[0098] It is known that the manufacturing process of lithium battery electrode sheet 200 includes slurry preparation, coating, drying, and rolling. The traditional electrode sheet 200 coating process usually adopts single-layer coating. When the coating is completed and the slurry is dried, the binder (such as SBR) in the slurry evaporates faster near the current collector 201. Therefore, the binder content of the electrode coating on the side near the current collector 201 is reduced, which reduces the peel force between the dried electrode coating and the current collector 201. During battery assembly and charging and discharging, the electrode sheet 200 coating is very easy to fall off, which affects battery performance and may even trigger battery safety issues due to short circuits.

[0099] To increase the peel strength between the electrode coating and the current collector 201, related technologies propose using a layered coating method to form the electrode sheet coating. That is, a first electrode coating and a second electrode coating are sequentially coated on the current collector. Compared to a single-layer, thicker electrode coating, this effectively mitigates the migration of binder to the surface during drying, improving the uniformity of binder distribution and thus enhancing the battery's peel strength and cycle stability. Furthermore, the first electrode coating, typically wider than the one closer to the current collector, is usually designed to be wider than the second electrode coating, which is narrower than the one further away. While layered coating can solve the problem of electrode sheet coating detachment, the difference in width between the first and second electrode coatings results in noticeable separation marks at the edges of the two layers.

[0100] Furthermore, there is no second electrode coating at the edge of the first electrode coating, meaning there is only one electrode coating at that location, thus forming a thinning zone. In the middle of the current collector, the total thickness of the electrode coating is set to the sum of the thickness of the first electrode coating and the thickness of the second electrode coating. The thickness of the electrode coating at the thinning zone is equivalent to the thickness of the first electrode coating, and the thickness difference of the electrode coating at the thinning zone is equivalent to the thickness of the second electrode coating. The thickness difference of the electrode coating at the thinning zone is relatively large. Thus, the layered coating method provided by the related technology is prone to causing appearance defects such as heavy separation marks between the upper and lower layers and excessive thickness difference in the thinning zone, thereby reducing the battery production yield.

[0101] In the embodiments of this utility model, please refer to Figure 5 The electrode sheet 200 includes a current collector 201, a first electrode coating 202, and a second electrode coating 203 stacked together. The first electrode coating 202 is disposed on one side surface 2011 of the current collector 201. The second electrode coating 203 is stacked on the side surface 2011 of the first electrode coating 202 facing away from the current collector 201. By setting the width of the second electrode coating 203 to be greater than the width of the first electrode coating 202, the peripheral edge 2031 of the second electrode coating 203 extends beyond the peripheral edge 2022 of the first electrode coating 202. Due to the shape... The slurry forming the second electrode coating 203 is a fluid. Therefore, during the coating process, the portion of the second electrode coating 203 that extends beyond the periphery will flow to the outer periphery of the first electrode coating 202. As a result, after the slurry dries, the portion of the second electrode coating 203 that extends beyond the first electrode coating 202 will surround the outer periphery of the first electrode coating 202, thereby forming a leveling portion 2032. The leveling portion 2032 can fill the step difference between the first electrode coating 202 and the current collector 201, thereby reducing the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203.

[0102] Furthermore, during the coating process, the portion of the second electrode coating 203 extending beyond the periphery flows to the outer periphery of the first electrode coating 202. This results in the second electrode coating 203, after drying, extending beyond the first electrode coating 202 and surrounding the outer periphery of the first electrode coating 202, forming a leveling portion 2032. Only one layer of electrode coating, the leveling portion 2032, exists on the outer periphery of the first electrode coating 202, thus creating a thinning zone. At the center of the current collector 201, the total thickness of the electrode coating is set to that of the first electrode coating. The thickness T1 of the first electrode coating 202 and the thickness T2 of the second electrode coating 203 are summed. The thickness of the electrode coating at the thinning area is set to the thickness T3 of the filling portion 2032. Therefore, the thickness difference of the electrode coating at the thinning area is set to ΔT = (T1 + T2) - T3. By setting the thickness T3 of the filling portion 2032 to be greater than the thickness T1 of the first electrode coating 202, the thickness difference ΔT is less than the thickness T2 of the second electrode coating 203. Compared with related technologies, the thickness difference at the thinning area in this invention is smaller, thereby improving the problem of a large thickness difference of the electrode coating in the thinning area in related technologies.

[0103] Thus, by setting the width of the second electrode coating 203 to be greater than the width of the first electrode coating 202, the peripheral edge 2031 of the second electrode coating 203 extends beyond the peripheral edge 2022 of the first electrode coating 202, and the extended portion surrounds the outer periphery of the first electrode coating 202, forming a filling portion 2032 on the outer periphery of the first electrode coating 202. In the stacking direction of the first electrode coating 202 and the second electrode coating 203, the thickness of the filling portion 2032 is greater than the thickness of the first electrode coating 202. This can improve the appearance defects of obvious dividing marks at the edges of the first electrode coating 202 and the second electrode coating 203, as well as the excessive thickness difference of the electrode coating at the thinning area, thereby improving the production yield of the battery.

[0104] In one embodiment, the total amount of slurry in the second electrode coating 203 is greater than the total amount of slurry in the first electrode coating 202. That is, during the convex coating process of the first electrode coating 202 and the second electrode coating 203, by setting the total amount of slurry in the second electrode coating 203 to be greater than the total amount of slurry in the first electrode coating 202, when coating the second electrode coating 203, while ensuring that the thickness of the second electrode coating 203 meets the requirements, there can still be enough slurry to flow to the outer periphery of the first electrode coating 202, and when the filling portion 2032 is formed on the outer periphery of the first electrode coating 202, the thickness of the filling portion 2032 can be greater than the thickness of the first electrode coating 202.

[0105] In one embodiment, the slurry of the first electrode coating 202 includes an active substance, a conductive agent, and a binder; the slurry of the second electrode coating 203 includes an active substance, a conductive agent, and a binder; the active substance, conductive agent, and binder in the slurry of the first electrode coating 202 are mixed in a first preset ratio; the active substance, conductive agent, and binder in the slurry of the second electrode coating 203 are mixed in a second preset ratio.

[0106] It is understood that in order to improve the peel strength of the electrode coating while ensuring battery cycle performance, the content of the binder usually needs to be set. The binder content is generally expressed as a mass percentage (wt%), that is, the percentage of the binder's mass to the total mass of the electrode slurry. In one embodiment, the mass percentage of the binder in the first electrode coating 202 is set as X, and the mass percentage of the binder in the second electrode coating 203 is set as Y; wherein,

[0107] In this embodiment, the first electrode coating 202 is disposed close to the current collector 201, and the second electrode coating 203 is disposed away from the current collector 201. By increasing the binder content in the first electrode coating 202 and setting a larger mass percentage of binder in the first electrode coating 202, the peel force between the first electrode coating 202 and the current collector 201 can be improved, thereby reducing the resistance of the electrode sheet 200. Furthermore, by setting a smaller mass percentage of binder in the second electrode coating 203, the second electrode coating 203 can be filled with more active material and conductive agent, thereby improving the cycle performance of the battery.

[0108] Furthermore, after increasing the mass percentage of the binder in the first electrode coating 202, the ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202 is set to a range of 0.2 to 0.8. When the ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202 is greater than 0.8, the mass percentage of the binder in the first electrode coating 202 is approximately the same as the mass percentage of the binder in the second electrode coating 203. The increase in binder content in the first electrode coating 202 is small, and the peel force between the first electrode coating 202 and the current collector 201 is not significantly improved. When the ratio of the mass percentage of binder in the second electrode coating 203 to the mass percentage of binder in the first electrode coating 202 is greater than 0.2, the binder content in the first electrode coating 202 is too large. Although it can significantly improve the peel force between the first electrode coating 202 and the current collector 201, the content of active material and conductive agent in the first electrode coating 202 is too small, which will affect the cycle performance of the battery.

[0109] This application does not impose specific limitations on the ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202. The ratio of the mass percentage of the binder in the second electrode coating 203 to the mass percentage of the binder in the first electrode coating 202 can be set to a range of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or any combination thereof.

[0110] This application does not impose specific limitations on the thickness of the first electrode coating 202 and the second electrode coating 203. Please refer to [link / reference]. Figure 5 The thickness T1 of the first electrode coating 202 can be 0.5μm to 5μm, for example, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm or any combination thereof. Controlling the thickness T1 of the first electrode coating 202 within a suitable range is beneficial to the tight connection between the first electrode coating 202 and the current collector 201, ensuring the safety performance of the battery, without affecting the energy density of the battery, and also helps to control costs.

[0111] Similarly, the thickness T2 of the second electrode coating 203 can be 1.5μm to 8μm, for example, 1.5μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm or any combination thereof. Controlling the thickness T2 of the second electrode coating 203 within a suitable range is beneficial for the tight connection between the second electrode coating 203 and the current collector 201, ensuring the safety performance of the battery, without affecting the energy density of the battery, and also helps to control costs.

[0112] Furthermore, the thicknesses of the first electrode coating 202 and the second electrode coating 203 can be the same or different. In one embodiment, the thicknesses of the first electrode coating 202 and the second electrode coating 203 are different. When the thickness T1 of the first electrode coating 202 is different from the thickness T2 of the second electrode coating 203, the thickness T2 of the second electrode coating 203 can be greater than or less than the thickness T1 of the first electrode coating 202.

[0113] In another embodiment, the thickness T1 of the first electrode coating 202 is the same as the thickness T2 of the second electrode coating 203. It is understood that when the first electrode coating 202 and the second electrode coating 203 are dried and then rolled, the rolling pressure on the second electrode coating 203 is greater than that on the first electrode coating 202. To ensure that the thickness T1 of the first electrode coating 202 is the same as the thickness T2 of the second electrode coating 203, the total amount of slurry in the second electrode coating 203 must be greater than that in the first electrode coating 202. Following this, the second electrode coating 203 has a lower binder content and a higher content of active material and conductive agent. Therefore, after rolling under greater pressure, the distribution of active material in the slurry of the second electrode coating 203 is more uniform and the density is higher, resulting in a higher energy density for the second electrode coating 203 and further improving the cycle performance of the battery.

[0114] In one embodiment, the width of the filling portion 2032 is set to W in the direction away from the peripheral edge 2022 of the first electrode coating 202, where 0.1mm ≤ W ≤ 0.5mm. The filling portion 2032 is provided to reduce the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203. When the width W of the filling portion 2032 is less than 0.1mm, the filling portion 2032 on the outer periphery of the first electrode coating 202 is too small, which is not conducive to reducing the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203; when the width W of the filling portion 2032 is greater than 0.5mm, the filling portion 2032 on the outer periphery of the first electrode coating 202 is too large, that is, too much slurry accumulates on the outer periphery of the first electrode coating 202, which easily leads to slurry waste. The width W of the filling portion 2032 is set to 0.1mm to 0.5mm. This reduces the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203 while saving slurry.

[0115] This application does not impose a specific limitation on the width of the filling part 2032, which can be a range of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any two of them.

[0116] In one embodiment, in the stacking direction of the first electrode coating 202 and the second electrode coating 203, the thickness of the first electrode coating 202 is set to T1, the thickness of the second electrode coating 203 is set to T2, and the thickness of the leveling portion 2032 is set to T3, wherein 0 ≤ (T1 + T2) - T3 ≤ 9 μm. The leveling portion 2032 is provided to reduce the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203. When the thickness difference of the electrode coatings in the thinning area is less than 0 μm, the surface of the leveling portion 2032 extends beyond the surface of the second electrode coating 203, meaning that too much slurry accumulates on the outer periphery of the first electrode coating 202, resulting in slurry waste. When the thickness difference of the electrode coatings in the thinning area is greater than 9 μm, the thickness of the leveling portion 2032 is too small, which is not conducive to reducing the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203. Setting the thickness difference of the electrode coating in the thinning area to 0-9 μm can save slurry while ensuring the reduction of the segmentation marks at the edges of the first electrode coating 202 and the second electrode coating 203.

[0117] This application does not impose specific limitations on the thickness difference of the electrode coating in the thinned area. The thickness difference of the electrode coating in the thinned area can be set to a range of 0 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or any combination thereof.

[0118] This application does not specifically limit the type of the electrode sheet 200. The electrode sheet 200 can be a positive electrode sheet or a negative electrode sheet. When the electrode sheet 200 is set as a positive electrode sheet, the electrode sheet 200 includes a positive current collector, a first positive electrode coating, and a second positive electrode coating stacked sequentially, and the positive current collector is set as aluminum foil; when the electrode sheet 200 is set as a negative electrode sheet, the electrode sheet 200 includes a negative current collector, a first negative electrode coating, and a second negative electrode coating stacked sequentially, and the negative current collector is set as copper foil.

[0119] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An electrode sheet coating apparatus characterized by comprising: It includes a coating die head and at least two material supply channels. The coating die head has a first outlet and a second outlet for spraying slurry into the collector, respectively. The first outlet is connected to one of the material supply channels, and the second outlet is connected to the other material supply channel. The electrode coating apparatus further includes: The storage components are located on the two feed paths and are used to store the demagnetized slurry. A fine filtration assembly, disposed on both of the aforementioned feed paths and located between the storage assembly and the coating die, is used to perform fine filtration on the demagnetized slurry; and, The material collection assembly is disposed on both of the material supply paths and is located between the fine filtration assembly and the coating die head, and is used to collect the slurry after fine filtration.

2. The electrode sheet coating apparatus according to claim 1, characterized by The fine filtration assembly includes two fine filtration sections, which are respectively disposed on the two feed flow paths. Each fine filtration section includes: The first-stage filter is located between the material storage assembly and the coating die head, and is used to perform coarse filtration on the slurry after demagnetization. A second-stage filter, positioned between the first-stage filter and the coating die, is used for intermediate filtration of the slurry after coarse filtration; and... The third-stage filter is located between the second-stage filter and the coating die head, and is used to perform fine filtration on the slurry after the intermediate filtration.

3. The electrode sheet coating apparatus according to claim 1, characterized by The storage assembly includes two storage tanks, which are respectively located on the two feeding paths. The storage tanks are used to store the demagnetized slurry on the corresponding feeding path. The material collection assembly includes two material collection tanks, which are respectively located on two material supply paths. The material collection tanks are used to collect the finely filtered slurry on the corresponding material supply path. The capacity of the collection tank is smaller than the capacity of the storage tank.

4. The electrode sheet coating apparatus according to claim 3, characterized by The capacity of the storage tank is set to 30-50L; The capacity of the collection tank is set to 5-15L.

5. The electrode sheet coating apparatus according to claim 1, wherein The electrode coating apparatus further includes: The batching components are located on the two feed paths and are used to prepare two slurries with different proportions. The demagnetizing components are separately located on the two feeding paths and between the dispensing component and the storage component, and are used to demagnetize the slurry respectively.

6. The electrode sheet coating apparatus according to claim 5, wherein The dispensing assembly includes two dispensing sections, which are located on the two feeding paths. Each dispensing section includes: Ingredient tanks; and, A stirring section is provided inside the mixing tank to stir the ingredients in the mixing tank evenly to form a slurry.

7. The electrode sheet coating apparatus according to claim 5, wherein The demagnetizing assembly includes two demagnetizing sections, which are disposed on the two feeding paths. Each demagnetizing section includes: The first-stage demagnetization is located between the batching component and the storage component, and is used to perform the first demagnetization treatment on the prepared slurry. A second-stage demagnetization process, positioned between the first-stage demagnetization and the storage assembly, is used to perform a second demagnetization treatment on the slurry after the first demagnetization process; and... The third-stage demagnetization is located between the second-stage demagnetization and the storage component, and is used to perform a third demagnetization on the slurry after the second demagnetization treatment.

8. The electrode tab coating apparatus according to claim 5, wherein The electrode coating device further includes a coarse filtration assembly, which includes two coarse filtration sections located on the two feed flow paths. The coarse filtration sections are situated between the demagnetizing assembly and the storage assembly, and are used to perform coarse filtration on the slurry after demagnetization.

9. The electrode tab coating apparatus according to claim 1, wherein The coating die head has an independent first flow channel and a second flow channel. The coating die head also has a first inlet and a second inlet. The first inlet is connected to the material supply flow path, and the second inlet is connected to the material supply flow path. The first inlet and the first outlet are connected to the first flow channel, and the second inlet and the second outlet are connected to the second flow channel.

10. The electrode sheet coating apparatus according to any one of claims 2 to 9, characterized by The electrode coating device further includes a feeding assembly, which includes two feeding pipelines. One of the feeding pipelines is at least located between the first outlet, the storage assembly, the fine filtration assembly, and the collection assembly to form one of the feeding paths. The other feeding pipeline is at least located between the second outlet, the storage assembly, the fine filtration assembly, and the collection assembly to form another feeding path.

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