Battery aluminum foil coating apparatus and coating method

Abstract

The present application discloses a battery aluminum foil coating apparatus and a coating method. The battery aluminum foil coating apparatus comprises an unwinding mechanism, a first surface coating assembly, a second surface coating assembly, and a winding mechanism. An aluminum foil sequentially passes through the unwinding mechanism, the first surface coating assembly, the second surface coating assembly, and the winding mechanism to complete double-surface coating, so that an aluminum foil carbon layer coating process and an electrode slurry coating process are combined, greatly reducing the production cost, and shortening the production period.

Description

Battery aluminum foil coating device and coating method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 28, 2023, with application number 202311277097.6. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery aluminum foil coating device and coating method. Background Art

[0003] At present, the use of functional coatings to treat the surface of battery conductive substrates is a breakthrough technological innovation. Carbon-coated aluminum foil or copper foil is to evenly and finely coat the dispersed nano-conductive graphite and carbon-coated particles on the aluminum foil or copper foil. It can provide excellent static conductivity, collect the microcurrent of active substances, improve the processing performance of the positive and negative electrodes of the battery, and enhance battery performance.

[0004] In the relevant design, the carbon layer coating of aluminum foil and the electrode slurry coating are two discontinuous processes. It is necessary to first complete the carbon layer coating and drying on the front and back of the aluminum foil respectively, and then coat the electrode slurry on the front and back of the aluminum foil and dry them. At the same time, the aluminum foil carbon coating process and the electrode slurry coating process require two winding and unwinding processes. The operation is cumbersome, the product realization cycle is long, and it consumes labor costs. SUMMARY OF THE INVENTION

[0005] The embodiments of the present application provide a battery aluminum foil coating device and a coating method to solve or at least partially solve the deficiencies of the above-mentioned background technology.

[0006] The embodiment of the present application provides a battery aluminum foil coating device, comprising:

[0007] Unwinding mechanism, used to unwind the coated aluminum foil;

[0008] A first-side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the first side of the aluminum foil, and to dry the coated first side of the aluminum foil;

[0009] The second side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the second side of the aluminum foil, and to dry the coated second side of the aluminum foil;

[0010] Rewinding mechanism, used for rewinding aluminum foil;

[0011] The aluminum foil passes through the unwinding mechanism, the first-side coating assembly, the second-side coating assembly and the winding mechanism in sequence to complete double-sided coating.

[0012] The present application also provides a coating method for battery aluminum foil, which comprises at least the following steps:

[0013] After the aluminum foil is unwound by the unwinding mechanism, it is introduced into the first-side coating assembly through the guide roller;

[0014] The aluminum foil enters the first-side coating assembly, and the carbon coating slurry and the electrode slurry are sequentially coated on the first side of the aluminum foil by the first-side coating assembly, and the coated first side of the aluminum foil is dried. The aluminum foil is then guided to the second-side coating assembly by a guide roller.

[0015] The aluminum foil enters the second-side coating assembly, which sequentially coats the second side of the aluminum foil with a carbon coating slurry and an electrode slurry. The coated second side of the aluminum foil is dried, and then the coated aluminum foil is guided to a winding mechanism via a guide roller.

[0016] The aluminum foil is rolled up by the rolling mechanism to complete the coating of the aluminum foil.

[0017] The beneficial effects of the present application are as follows: an embodiment of the present application provides a battery aluminum foil coating device and a coating method, the battery aluminum foil coating device includes a unwinding mechanism, a first-side coating component, a second-side coating component and a winding mechanism, wherein the unwinding mechanism is used to unwind aluminum foil, the first-side coating component is used to sequentially coat a carbon coating layer slurry and an electrode slurry on the first side of the aluminum foil, and dry the first side of the coated aluminum foil, the second-side coating component is used to sequentially coat a carbon coating layer slurry and an electrode slurry on the second side of the aluminum foil, and dry the second side of the coated aluminum foil, and the winding mechanism is used to wind up the aluminum foil; double-sided coating is completed by passing the aluminum foil through the unwinding mechanism, the first-side coating component, the second-side coating component and the winding mechanism in sequence, thereby combining the aluminum foil carbon layer coating process and the electrode slurry coating process, greatly reducing production costs, shortening production cycles and reducing resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic structural diagram of a battery aluminum foil carbon layer coating device in the related art;

[0019] FIG2 is a schematic structural diagram of a battery aluminum foil electrode slurry coating device in the related art;

[0020] FIG3 is a schematic structural diagram of a battery aluminum foil coating device provided in an embodiment of the present application;

[0021] FIG4 is a flow chart of a coating method for battery aluminum foil provided in an embodiment of the present application.

[0022] FIG5 is a schematic diagram of the structure of the first side of the aluminum foil after the electrode slurry coating process on both sides is completed in the related art;

[0023] FIG6 is a schematic structural diagram of the first side of the battery aluminum foil provided in an embodiment of the present application after the double-sided coating process is completed;

[0024] FIG7 is a graph showing the cycle capacity retention rate of the electrode cell produced by the battery aluminum foil coating process provided in Comparative Example 1 and the cycle capacity retention rate of the electrode cell produced by the battery aluminum foil coating process provided in this embodiment.

[0025] Description of Reference Numerals

[0026] 10-battery aluminum foil carbon layer coating device; 20-battery aluminum foil electrode slurry coating device; 30-battery aluminum foil coating device;

[0027] 11-first aluminum foil unwinding mechanism; 12-aluminum foil corona mechanism; 13-aluminum foil first side carbon layer coating mechanism; 14-first aluminum foil drying oven; 15-aluminum foil second side carbon layer coating mechanism; 16-second aluminum foil drying oven; 17-first aluminum foil winding mechanism;

[0028] 21-second aluminum foil unwinding mechanism; 22-aluminum foil first side electrode slurry coating mechanism; 23-third aluminum foil drying oven; 24-aluminum foil second side electrode slurry coating mechanism; 25-fourth aluminum foil drying oven; 26-second aluminum foil winding mechanism;

[0029] 30A - carbon coating slurry; 30B - electrode slurry; 31 - unwinding mechanism; 32 - corona mechanism; 33 - first side coating assembly; 34 - second side coating assembly; 35 - winding mechanism;

[0030] 331 - first carbon layer coating mechanism; 332 - first electrode slurry coating mechanism; 333 - first oven;

[0031] 341 - second carbon layer coating mechanism; 342 - second electrode slurry coating mechanism; 343 - second oven. Modes for Carrying Out the Invention

[0032] In the description of this application, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed or detachable connections, mechanical or electrical connections, direct or indirect connections through an intermediate medium, and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0033] In the description of this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] This embodiment provides a battery aluminum foil coating device and coating method. Detailed descriptions are provided below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments.

[0035] Please refer to Figures 3 to 4. This embodiment provides a battery aluminum foil coating device and a coating method. The battery aluminum foil coating device 30 includes a unwinding mechanism 31, a first-side coating component 33, a second-side coating component 34, and a winding mechanism 35. The unwinding mechanism 31 is used to unwind the aluminum foil. The first-side coating component 33 is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the first side of the aluminum foil, and dry the first side of the coated aluminum foil. The second-side coating component 34 is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the second side of the aluminum foil, and dry the second side of the coated aluminum foil. The winding mechanism 35 is used to wind up the coated aluminum foil; wherein, the aluminum foil passes through the unwinding mechanism 31, the first-side coating component 33, the second-side coating component 34, and the winding mechanism 35 in sequence to complete double-sided coating.

[0036] It should be noted that carbon-coated aluminum foil or copper foil is to evenly and finely coat the dispersed nano-conductive graphite and carbon-coated particles on the aluminum foil or copper foil. It can provide excellent static conductivity, collect the microcurrent of the active substance, improve the processing performance of the positive and negative electrodes of the battery, and enhance the battery performance. At present, most lithium battery companies directly purchase carbon-coated aluminum foil for coating, which is costly. In order to reduce the cost of incoming materials, some companies purchase lower-priced double-sided plain aluminum foil, and then perform carbon layer coating and electrode slurry processes on the surface of the aluminum foil in turn to prepare the electrode plates to be cut.

[0037] Specifically, please refer to Figure 1 which is a structural schematic diagram of a battery aluminum foil carbon layer coating device in the related art. In the related art, the battery aluminum foil carbon layer coating device 10 includes a first aluminum foil unwinding mechanism 11, an aluminum foil corona mechanism 12, an aluminum foil first side carbon layer coating mechanism 13, a first aluminum foil oven 14, an aluminum foil second side carbon layer coating mechanism 15, a second aluminum foil oven 16 and a first aluminum foil winding mechanism 17, wherein the aluminum foil is sequentially fed into the first aluminum foil unwinding mechanism 11, the aluminum foil corona mechanism 12, the aluminum foil first side carbon layer coating mechanism 13, the first aluminum foil oven 14, the aluminum foil second side carbon layer coating mechanism 15, the second aluminum foil oven 16 and the first aluminum foil winding mechanism 17, thereby completing the carbon layer coating process on both sides of the aluminum foil.

[0038] Please refer to FIG2 for a structural diagram of a battery aluminum foil electrode slurry coating device in the related art. In the related art, the battery aluminum foil electrode slurry coating device 20 includes a second aluminum foil unwinding mechanism 21, an aluminum foil first side electrode slurry coating mechanism 22, a third aluminum foil drying oven 23, an aluminum foil second side electrode slurry coating mechanism 24, a fourth aluminum foil drying oven 25, and a second aluminum foil winding mechanism 26; wherein, the aluminum foil that has completed the double-sided carbon layer coating process is sequentially fed into the second aluminum foil unwinding mechanism 21, the aluminum foil first side electrode slurry coating mechanism 22, the third aluminum foil drying oven 23, the aluminum foil second side electrode slurry coating mechanism 24, the fourth aluminum foil drying oven 25, and the second aluminum foil winding mechanism 26. The first-side electrode slurry coating mechanism 22, the third aluminum foil oven 23, the second-side aluminum foil electrode slurry coating mechanism 24, the fourth aluminum foil oven 25 and the second aluminum foil winding mechanism 26 complete the electrode slurry coating process on both sides of the aluminum foil; it can be understood that in the relevant technology, the aluminum foil carbon layer coating and the electrode slurry coating are two discontinuous processes, and the aluminum foil carbon coating process and the electrode slurry coating process need to go through two winding and unwinding processes, the operation is cumbersome, the product realization cycle is long and it consumes labor costs.

[0039] It can be understood that the embodiment of the present application is to set up the battery aluminum foil coating device including an unwinding mechanism, a first-side coating component, a second-side coating component and a winding mechanism. The unwinding mechanism is used to unwind the aluminum foil, the first-side coating component is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the first side of the aluminum foil, and dry the first side of the coated aluminum foil, the second-side coating component is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the second side of the aluminum foil, and dry the second side of the coated aluminum foil, and the winding mechanism is used to wind up the coated aluminum foil; wherein, the aluminum foil passes through the unwinding mechanism, the first-side coating component, the second-side coating component and the winding mechanism in sequence to complete double-sided coating, thereby combining the aluminum foil carbon layer coating process and the electrode slurry coating process, greatly reducing production costs, shortening production cycles and reducing resource waste.

[0040] The technical solution of this application is now described in conjunction with specific embodiments.

[0041] Please refer to FIG3 , which is a schematic structural diagram of a battery aluminum foil coating device provided in an embodiment of the present application.

[0042] The present embodiment provides a battery aluminum foil coating device 30, which includes an unwinding mechanism 31, a first-side coating component 33, a second-side coating component 34 and a winding mechanism 35. The unwinding mechanism 31 is used to unwind the aluminum foil, the first-side coating component 33 is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the first side of the aluminum foil, and dry the first side of the coated aluminum foil, the second-side coating component 34 is used to sequentially coat the carbon coating layer slurry and the electrode slurry on the second side of the aluminum foil, and dry the second side of the coated aluminum foil, and the winding mechanism 35 is used to wind up the coated aluminum foil.

[0043] Among them, the unwinding mechanism 31, the first surface coating component 33, the second surface coating component 34 and the winding mechanism 35 can be connected through tape walking. This embodiment does not impose specific restrictions on the connection method between the above mechanisms and / or components.

[0044] Furthermore, in this embodiment, the first-side coating assembly 33 is located between the unwinding mechanism 31 and the second-side coating assembly 34, and the first-side coating assembly 33 includes a first carbon layer coating mechanism 331, a first electrode slurry coating mechanism 332 and a first oven 333 connected in sequence; wherein, the first carbon layer coating mechanism 331 is used to coat the carbon layer slurry on the first side of the aluminum foil, the first electrode slurry coating mechanism 332 is used to coat the electrode slurry on the first side of the aluminum foil after coating the carbon layer slurry, and the first oven 333 is used to dry the first side of the aluminum foil after coating.

[0045] Among them, the first carbon layer coating mechanism 331 can be located at any position of the front end, rear end, above or below the first electrode slurry coating mechanism 332, as long as the aluminum foil can be fed into the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332 and the first oven 333 in sequence. That is, this embodiment does not impose any specific restrictions on the positions of the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332 and the first oven 333.

[0046] Furthermore, in this embodiment, the second-side coating assembly 34 includes a second carbon layer coating mechanism 341, a second electrode slurry coating mechanism 342 and a second oven 343 connected in sequence; wherein, the second carbon layer coating mechanism 341 is used to coat the carbon layer slurry on the second side of the aluminum foil, the second electrode slurry coating mechanism 342 is used to coat the electrode slurry on the second side of the aluminum foil after coating the carbon layer slurry, and the second oven 343 is used to dry the second side of the aluminum foil after coating.

[0047] Among them, the second carbon layer coating mechanism 341 can be located at any position of the front end, rear end, top or bottom of the second electrode slurry coating mechanism 342, as long as the aluminum foil can be fed into the second carbon layer coating mechanism 341, the second electrode slurry coating mechanism 342 and the second oven 343 in sequence. That is, this embodiment does not impose any specific restrictions on the positions of the second carbon layer coating mechanism 341, the second electrode slurry coating mechanism 342 and the second oven 343.

[0048] Specifically, in this embodiment, the aluminum foil passes through the unwinding mechanism 31, the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332, the first oven 333, the second carbon layer coating mechanism 341, the second electrode slurry coating mechanism 342, the second oven 343 and the winding mechanism 35 in sequence to complete double-sided coating; it can be understood that compared with the disadvantage of higher costs caused by directly purchasing carbon-coated aluminum foil for electrode slurry coating, this embodiment combines the aluminum foil carbon layer coating process and the electrode slurry coating process through the battery aluminum foil coating device 30, thereby achieving double-sided coating of the aluminum foil and reducing production costs.

[0049] It should be noted that, in combination with Figures 1 and 2, in the relevant technology, the carbon layer coating of aluminum foil and the electrode slurry coating are two discontinuous processes. In order to reduce the cost of incoming materials, some companies purchase lower-priced double-sided smooth aluminum foil, which requires additional factories to carry out the carbon coating process on the surface of the aluminum foil. At the same time, the carbon-coated aluminum foil needs to be dried in an oven. After carbon coating, the aluminum foil is sent to the electrode coating workshop for electrode slurry coating, which requires a lot of money and time.

[0050] It can be understood that, in this embodiment, by setting the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332 and the first oven 333, after the carbon layer slurry is coated on the first side of the aluminum foil, there is no need to perform a drying process, and the electrode slurry is directly coated on the first side of the aluminum foil coated with the carbon layer slurry, and then the first side of the aluminum foil coated with the carbon layer slurry is dried by the first oven 333, thereby sequentially coating the carbon layer slurry and the electrode slurry on the first side of the aluminum foil; by setting the second carbon layer coating mechanism 341 and the second electrode slurry coating mechanism 342 and the second oven 343, after coating the carbon coating slurry on the second side of the aluminum foil, there is no need to perform a drying process, and the electrode slurry is directly coated on the second side of the aluminum foil coated with the carbon coating slurry, and then the first side of the coated aluminum foil is dried by the second oven 343, thereby completing the double-sided coating of the aluminum foil. Compared with the related art in which the aluminum foil carbon layer coating and the electrode slurry coating are two discontinuous processes, the battery aluminum foil coating device 30 provided in this embodiment effectively reduces the tediousness of the operation, saves oven space, reduces the manufacturing cost and saves land space.

[0051] Moreover, compared with the related art, in which the aluminum foil coating process requires two coatings and two rewindings, in the battery aluminum foil coating device provided in this embodiment, the aluminum foil only needs one unwinding and one rewinding to achieve double-sided coating of the aluminum foil, effectively reducing the complexity of the operation, while avoiding manual handling of the aluminum foil material and saving manpower.

[0052] Furthermore, in this embodiment, a carbon coating slurry and an electrode slurry are sequentially coated on the first surface of the aluminum foil. The carbon coating slurry can improve the current collector conductivity of the aluminum foil and increase the adhesion of the positive electrode material on the electrode sheet; wherein, the viscosity of the carbon coating slurry is in the range of greater than or equal to 30 mPa·s and less than or equal to 500 mPa·s; the viscosity of the electrode slurry is in the range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s; the solid content of the electrode slurry is greater than or equal to 67% and less than or equal to 69%; wherein, the solid content of the electrode slurry is greater than the solid content of the carbon coating slurry.

[0053] It can be understood that, compared with the related art, in which the carbon coating slurry and the electrode slurry are mixed and then coated on the aluminum foil, the present application sequentially coats the carbon coating slurry and the electrode slurry on the first side of the aluminum foil, so that the carbon coating slurry and the electrode slurry are in contact with each other and mutually dissolved at the contact interface between the two, thereby greatly increasing the contact area between the two materials and improving the conductivity; at the same time, by setting the solid content of the electrode slurry to be greater than the solid content of the carbon coating slurry, the electrode slurry and the carbon coating slurry are prevented from being completely mutually dissolved as a whole; and, by setting the viscosity of the carbon coating slurry to a range of greater than or equal to 30 mPa·s and less than or equal to 500 mPa·s, the viscosity of the electrode slurry is in a range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s, so that the adhesion between the carbon coating slurry and the electrode slurry is better, thereby improving the peeling force when the aluminum foil is subsequently used as a battery electrode, and optimizing and improving the battery performance.

[0054] Specifically, the solvent system of the carbon coating layer slurry is the same as the solvent system of the electrode slurry; wherein, this embodiment takes the electrode slurry as the positive electrode slurry as an example to illustrate the technical solution of the present application.

[0055] In this embodiment, the solvent of the carbon coating slurry and the electrode slurry are both oily systems. The electrode slurry includes an active substance, a binder, a dispersant, a conductive agent and an organic solvent, wherein the active substance can be lithium iron phosphate, the binder can be polyvinylidene fluoride, the dispersant can be YTF003 dispersant, the conductive agent can be carbon nanotubes, and the organic solvent can be N-methylpyrrolidone (NMP). The carbon coating slurry includes carbon material powder, a film-forming agent, an organic solvent and an additive, wherein the carbon material powder can be selected from carbon black (SP) or graphene (GR), and the organic solvent can be N-methylpyrrolidone (NMP).

[0056] It can be understood that in this embodiment, the solvent system of the carbon coating layer slurry is set to be the same as the solvent system of the electrode slurry. Since the two belong to the same system, the carbon coating layer slurry and the electrode slurry can be mutually soluble in each other at their junction, and can be dried together in the subsequent drying process.

[0057] Furthermore, in this embodiment, the battery aluminum foil coating device 30 also includes a corona mechanism 32 and a correction mechanism, the corona mechanism 32 is used to remove oil stains on the surface of the aluminum foil before aluminum foil coating; the correction mechanism is arranged between the first carbon layer coating mechanism and the first electrode slurry coating mechanism; and / or, the correction mechanism is arranged between the first oven and the second oven; and / or, the correction mechanism is arranged between the second carbon layer coating mechanism and the second electrode slurry coating mechanism; and / or, the correction mechanism is arranged between the second oven and the winding mechanism; the correction mechanism is used to adjust the aluminum foil running deviation and coating misalignment.

[0058] Specifically, the correcting mechanism includes a first correcting structure, a second correcting structure, a third correcting structure and a fourth correcting structure; the first correcting structure is used to detect whether the carbon coating slurry and the electrode slurry coated on the first side of the aluminum foil are misaligned, and to adjust the coating misalignment of the carbon coating slurry and the electrode slurry on the first side of the aluminum foil; the second correcting structure is used to detect whether the aluminum foil is misaligned when it is conveyed on the conveyor between the first oven 333 and the second carbon layer coating mechanism 341, and to adjust the deviation of the aluminum foil conveyor; the third correcting structure is used to detect whether the carbon coating slurry and the electrode slurry coated on the second side of the aluminum foil are misaligned, and to adjust the coating misalignment of the carbon coating slurry and the electrode slurry on the second side of the aluminum foil; the second correcting structure is used to detect whether the aluminum foil is misaligned when it is conveyed on the conveyor between the second oven 343 and the winding mechanism 35, and to adjust the deviation of the aluminum foil conveyor.

[0059] It can be understood that, in this embodiment, by providing the first, second, third, and fourth correcting structures, the deviation of the aluminum foil and the coating misalignment are monitored and adjusted, thereby improving the coating accuracy of the aluminum foil and stabilizing the travel of the aluminum foil.

[0060] Please refer to Figures 3 and 4; Figure 4 is a flow chart of the battery aluminum foil coating method provided in an embodiment of the present application.

[0061] This embodiment also provides a method for coating battery aluminum foil. It should be noted that one embodiment of the battery electrode sheet coating method is to use the above-mentioned battery aluminum foil coating device 30 to coat the aluminum foil, thereby forming the electrode sheet to be cut.

[0062] The battery pole piece coating method comprises the following steps:

[0063] Step S10: After the aluminum foil is unwound by the unwinding mechanism 31 , it is introduced into the first-side coating assembly 33 through the guide roller.

[0064] Specifically, the step S10 includes the following steps:

[0065] Step S11: After the aluminum foil is unwound by the unwinding mechanism 31, it is sent to the corona mechanism 32 through the belt conveyor. The corona mechanism 32 is used to remove oil stains on the surface of the aluminum foil.

[0066] Among them, after the surface oil stains of the aluminum foil are removed, the thickness / surface density of the aluminum foil and copper foil can be detected by a foil detection device. If the thickness / surface density of the aluminum foil and copper foil meets the preset thickness / surface density, step S12 is performed; if the thickness / surface density of the aluminum foil and copper foil does not meet the preset thickness / surface density, the thickness / surface density of the aluminum foil and copper foil is adjusted; it should be noted that this embodiment does not specifically limit the foil detection equipment, the preset thickness / surface density, and the method for adjusting the thickness / surface density of the aluminum foil and copper foil.

[0067] Step S12: After the aluminum foil enters the corona mechanism 32, it is guided into the first-side coating assembly 33 through the guide roller.

[0068] Step S20: The aluminum foil enters the first-side coating assembly 33, and the carbon coating slurry and the electrode slurry are sequentially coated on the first side of the aluminum foil using the first-side coating assembly 33, and the coated first side of the aluminum foil is dried, and then the aluminum foil is introduced into the second-side coating assembly 34 through the guide roller.

[0069] Specifically, the step S20 includes the following steps:

[0070] Step S21 : the aluminum foil enters the first carbon layer coating mechanism 331 , and the first carbon layer coating mechanism 331 is used to coat the carbon layer slurry on the first surface of the aluminum foil, and then the aluminum foil is sent to the first electrode slurry coating mechanism 332 .

[0071] Specifically, the coating method of the carbon coating layer slurry includes but is not limited to gravure transfer coating. The first electrode slurry coating mechanism 332 includes a first gravure coating roller, which drives the aluminum foil to move to coat the first surface of the carbon coating layer slurry.

[0072] Step S22 : the aluminum foil enters the first electrode slurry coating mechanism 332 , and the electrode slurry is coated on the first surface of the aluminum foil coated with the carbon coating slurry by the first electrode slurry coating mechanism 332 , and then the aluminum foil is sent into the first oven 333 .

[0073] The drying temperature of the first oven is in the range of greater than or equal to 85 degrees Celsius and less than or equal to 105 degrees Celsius, and the drying time of the aluminum foil in the first oven is in the range of greater than or equal to 2 minutes and less than or equal to 4 minutes.

[0074] Specifically, the orthographic projection of the electrode slurry on the first side of the aluminum foil overlaps with the orthographic projection of the carbon coating slurry on the first side of the aluminum foil, and the coating method of the electrode slurry includes but is not limited to one of transfer coating, extrusion coating or wet coating.

[0075] Furthermore, the viscosity of the carbon coating slurry is in the range of greater than or equal to 30 mPa·s and less than or equal to 500 mPa·s; the solid content of the carbon coating slurry is greater than or equal to 9% and less than or equal to 10%; the viscosity of the electrode slurry is in the range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s; the viscosity of the electrode slurry is in the range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s; the solid content of the electrode slurry is greater than or equal to 67% and less than or equal to 69%.

[0076] It should be noted that in this embodiment, the solvent system of the carbon coating slurry is the same as the solvent system of the electrode slurry. Since the two belong to the same system, the carbon coating slurry and the electrode slurry can be mutually soluble in each other at their junction, and can be dried together in the subsequent drying process.

[0077] Step S23: the aluminum foil enters the first drying oven 333 , and the first side of the coated aluminum foil is dried in the first drying oven 333 , and then the aluminum foil is guided into the second side coating assembly 34 via a guide roller.

[0078] Specifically, there is a flowing high-temperature airflow in the first oven 333, and the solvent of the carbon coating layer slurry and the solvent of the electrode slurry are carried away by the flowing high-temperature airflow, thereby drying the first side of the aluminum foil; it should be noted that the first side of the dried aluminum foil can ensure the stability of the aluminum carbon coating layer slurry and the electrode slurry through the airflow cooling system, the tensioning system, the dry film detection system and the correction structure.

[0079] Step S30: The aluminum foil enters the second-side coating assembly 34, and the carbon coating slurry and the electrode slurry are sequentially coated on the second side of the aluminum foil using the second-side coating assembly 34, and the second side of the coated aluminum foil is dried, and then the coated aluminum foil is introduced into the winding mechanism 35 through the guide roller.

[0080] Specifically, the step S30 includes the following steps:

[0081] Step S31 : the aluminum foil enters the second carbon layer coating mechanism 341 , and the second carbon layer coating mechanism 341 is used to coat the carbon layer slurry on the second surface of the aluminum foil, and then the aluminum foil is sent to the second electrode slurry coating mechanism 342 .

[0082] Specifically, the second electrode slurry coating mechanism 342 includes a second gravure coating roller, and the second gravure coating roller drives the aluminum foil to move to coat the second surface with the carbon coating slurry.

[0083] Step S32: The aluminum foil enters the second electrode slurry coating mechanism 342, and the electrode slurry is coated on the second side of the aluminum foil after being coated with the carbon coating slurry by the second electrode slurry coating mechanism 342, and then the aluminum foil is sent to the second oven 343; wherein, the orthographic projection of the electrode slurry on the second side of the aluminum foil overlaps with the orthographic projection of the carbon coating slurry on the second side of the aluminum foil.

[0084] Step S33: the aluminum foil enters the second drying oven 343 , and the second surface of the coated aluminum foil is dried in the second drying oven 343 , and then the coated aluminum foil is introduced into the winding mechanism 35 through the guide roller.

[0085] Among them, the drying temperature range of the second oven is greater than or equal to 90 degrees Celsius and less than or equal to 115 degrees Celsius, and the drying time of the aluminum foil in the second oven is greater than or equal to 2 minutes and less than or equal to 4 minutes; it can be understood that this embodiment avoids the phenomenon that the solvent of the carbon coating layer slurry and the solvent of the electrode slurry remain on the first side of the aluminum foil after the double-sided coating of the aluminum foil is completed by setting the drying temperature of the second oven to be greater than the drying temperature of the first oven.

[0086] Specifically, there is a flowing high-temperature airflow in the second oven 343, and the solvent of the carbon coating layer slurry and the solvent of the electrode slurry are carried away by the flowing high-temperature airflow, thereby drying the second side of the aluminum foil; it should be noted that the second side of the dried aluminum foil can ensure the stability of the aluminum carbon coating layer slurry and the electrode slurry through the airflow cooling system, tensioning system, dry film detection system and correction structure.

[0087] Step S40: The aluminum foil is rolled up by the rolling mechanism 35 to complete the coating of the aluminum foil.

[0088] It can be understood that the embodiment of the present application combines the aluminum foil carbon layer coating process and the electrode slurry coating process. The aluminum foil passes through the unwinding mechanism, the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332, the first oven 333, the second carbon layer coating mechanism 341, the second electrode slurry coating mechanism 342, the second oven 343 and the winding mechanism 35 in sequence to complete double-sided coating, which greatly reduces production costs, shortens production cycles, reduces resource waste, and saves land space.

[0089] Further, please refer to the following comparative example 1, which is a coating method of battery aluminum foil in the related art.

[0090] Comparative Example 1:

[0091] The coating method of the battery aluminum foil of this comparative example 1 comprises the following steps:

[0092] D10: The aluminum foil is sequentially fed into the aluminum foil unwinding mechanism, the aluminum foil corona mechanism, the aluminum foil first side carbon layer coating mechanism, the first aluminum foil drying oven, the aluminum foil second side carbon layer coating mechanism, the second aluminum foil drying oven and the first aluminum foil winding mechanism, thereby completing the double-sided carbon layer coating process of the aluminum foil.

[0093] Specifically, in the relevant technology, the carbon layer coating speed ranges from 180 m / min to 200 m / min, the temperature range of the first aluminum foil oven is 85 degrees Celsius to 105 degrees Celsius, and the drying time of the first side of the aluminum foil in the first aluminum foil oven is 0.1 minute; the coating speed of the second side of the aluminum foil is consistent with the coating speed of the second side of the aluminum foil. When the carbon layer is coated on 10,000 meters of aluminum foil, it takes at least 50 minutes; among them, the winding and transportation time is time-consuming, and many factories need to separate the factory that completes the carbon layer coating from the factory that completes the electrode slurry coating. The time consumed by the aluminum foil during transportation takes at least 30 minutes.

[0094] D20: The aluminum foil that has completed the double-sided carbon layer coating process is sequentially sent to the second aluminum foil unwinding mechanism, the aluminum foil first side electrode slurry coating mechanism, the third aluminum foil oven, the aluminum foil second side electrode slurry coating mechanism, the fourth aluminum foil oven and the second aluminum foil winding mechanism, thereby completing the double-sided electrode slurry coating process of the aluminum foil.

[0095] Specifically, in the related art, the electrode slurry coating speed is 40 m / min, the drying time of the first side of the aluminum foil in the first aluminum foil oven is in the range of 2 minutes to 4 minutes, and the drying time of the second side of the aluminum foil in the second aluminum foil oven is in the range of 2 minutes to 4 minutes.

[0096] From the above, it can be seen that in Comparative Example 1, the carbon layer coating process and the electrode slurry coating process are completed separately; wherein, the time for completing the carbon layer coating process on both sides of the aluminum foil includes:

[0097] The time for carbon coating the first side of the aluminum foil, the time for drying the slurry of the carbon layer coated on the first side of the aluminum foil, the time for carbon coating the second side of the aluminum foil, the time for drying the slurry of the carbon layer coated on the second side of the aluminum foil, the time for transporting the aluminum foil with double-sided carbon coating from the carbon layer coating factory to the electrode slurry coating factory, the time for coating the first side of the aluminum foil with electrode slurry, the time for drying the electrode slurry on the first side of the aluminum foil, the time for coating the second side of the aluminum foil with electrode slurry, and the time for drying the slurry of the electrode slurry layer on the second side of the aluminum foil; specifically, in the related art, it takes at least 330 minutes for the aluminum foil to complete the double-sided carbon layer coating process and the double-sided electrode slurry coating process.

[0098] By comparison, it can be seen that in the coating method of battery aluminum foil provided in the embodiment, the aluminum foil passes through the unwinding mechanism, the first carbon layer coating mechanism 331, the first electrode slurry coating mechanism 332, the first oven 333, the second carbon layer coating mechanism 341, the second electrode slurry coating mechanism 342, the second oven 343 and so on in sequence, thereby saving the time for completing the carbon layer coating of the aluminum foil alone in the related art; and, by combining the aluminum foil carbon layer coating process and the electrode slurry coating process, while saving the time for transporting the aluminum foil with double-sided carbon layer coating from the carbon layer coating factory to the electrode slurry coating factory, the production cost is greatly reduced, the production cycle is shortened, the waste of resources is reduced, and land space is saved.

[0099] Further, please refer to Figures 5 and 6; Figure 5 is a structural schematic diagram of the first side of the aluminum foil after the double-sided electrode slurry coating process is completed in the related art; Figure 6 is a structural schematic diagram of the first side of the battery aluminum foil provided in an embodiment of the present application after the double-sided coating process is completed.

[0100] As can be seen from Figure 5, in the related art, since the carbon layer coating process and the electrode slurry coating process are completed separately, when the electrode slurry 10B is coated on the first side of the aluminum foil, the carbon coating layer slurry 10A has been dried. Therefore, on the first side of the aluminum foil, there is no contact and fusion area between the electrode slurry 10B and the carbon coating layer slurry 10A; as can be seen from Figure 6, in this embodiment, by combining the aluminum foil carbon layer coating process and the electrode slurry coating process, the solvent system of the carbon coating layer slurry is the same as the solvent system of the electrode slurry. Therefore, when the electrode slurry 30B is coated on the first side of the aluminum foil, that is, before the aluminum foil enters the first oven, there is a contact and fusion layer P between the electrode slurry 30B and the carbon coating layer slurry 30A; wherein, the thickness of the contact and fusion layer P ranges from 0.5 microns to 1 micron.

[0101] Specifically, in order to explore whether the contact fusion layer P affects the overall performance of the battery, the electrode pieces produced by the coating process of the battery aluminum foil provided in Comparative Example 1 and the electrode pieces produced by the coating process of the battery aluminum foil provided in this embodiment were taken, and the parameters of the electrode pieces produced by the two processes were tested.

[0102] Please refer to Table 1, which is a data table showing the thickness of the electrode produced by the coating process of the battery aluminum foil provided in Comparative Example 1 and the thickness of the electrode produced by the coating process of the battery aluminum foil provided in this embodiment.

[0103]

[0104] Table 1

[0105] Among them, 100m of each process was used to produce, and 10m of the electrode with stable coating surface density data was taken for cold pressing and continuous uniform testing of 45 sets of data. The average thickness of the electrode produced by the coating process of the battery aluminum foil provided in Comparative Example 1 was 181.49 microns, and the average thickness of the electrode produced by the coating process of the battery aluminum foil provided in this embodiment was 181.47 microns. Therefore, the difference in thickness of the electrode produced by the two processes can be ignored, that is, in the coating method of the battery aluminum foil provided in this embodiment, the contact fusion layer P will not affect the thickness of the electrode.

[0106] Please refer to Figure 7, which is a graph showing the cycle capacity retention rate of the electrode cell produced by the battery aluminum foil coating process provided in Comparative Example 1 and the cycle capacity retention rate of the electrode cell produced by the battery aluminum foil coating process provided in this embodiment.

[0107] By comparison, it can be seen that there is no significant difference in the capacity retention rate of the electrode cell after 156 cycles produced by the coating process of the battery aluminum foil provided in Comparative Example 1 and the capacity retention rate of the electrode cell after 156 cycles produced by the coating process of the battery aluminum foil provided in this embodiment; that is, in the coating method of the battery aluminum foil provided in this embodiment, the contact fusion layer P will not affect the cycle of the electrode cell.

Claims

1. A battery aluminum foil coating device, wherein: include: Unwinding mechanism, used for unwinding aluminum foil; A first-side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the first side of the aluminum foil, and dry the coated first side of the aluminum foil; A second side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the second side of the aluminum foil, and dry the coated second side of the aluminum foil; The winding mechanism is used to wind up the coated aluminum foil; The aluminum foil passes through the unwinding mechanism, the first-side coating assembly, the second-side coating assembly and the winding mechanism in sequence to complete double-sided coating.

2. The battery aluminum foil coating device according to claim 1, wherein: The first-side coating assembly is located between the unwinding mechanism and the second-side coating assembly; The first-side coating assembly includes a first carbon layer coating mechanism, a first electrode slurry coating mechanism and a first oven which are connected in sequence; The second-side coating assembly includes a second carbon layer coating mechanism, a second electrode slurry coating mechanism and a second oven which are connected in sequence; The aluminum foil passes through the unwinding mechanism, the first carbon layer coating mechanism, the first electrode slurry coating mechanism, the first oven, the second carbon layer coating mechanism, the second electrode slurry coating mechanism, the second oven and the winding mechanism in sequence to complete double-sided coating.

3. The battery aluminum foil coating device according to claim 2, wherein: The drying temperature of the first oven is lower than the drying temperature of the second oven.

4. The battery aluminum foil coating device according to claim 3, wherein: The drying temperature of the first oven is in the range of greater than or equal to 85 degrees Celsius and less than or equal to 105 degrees Celsius, and the drying time of the aluminum foil in the first oven is in the range of greater than or equal to 2 minutes and less than or equal to 4 minutes; The drying temperature of the second oven is in the range of greater than or equal to 90 degrees Celsius and less than or equal to 115 degrees Celsius, and the drying time of the aluminum foil in the second oven is in the range of greater than or equal to 2 minutes and less than or equal to 4 minutes.

5. The battery aluminum foil coating device according to claim 1, wherein: The battery aluminum foil coating device further includes a deviation correction mechanism, which is arranged on the first carbon layer coating mechanism and the first electrode slurry coating mechanism; And / or, the deviation-correcting mechanism is disposed between the first oven and the second oven; And / or, the deviation correction mechanism is arranged between the second carbon layer coating mechanism and the second electrode slurry coating mechanism; And / or, the deviation correcting mechanism is arranged between the second oven and the winding mechanism.

6. The battery aluminum foil coating device according to claim 1, wherein: The viscosity of the carbon coating slurry is in the range of greater than or equal to 30 mPa·s and less than or equal to 500 mPa·s; the solid content of the carbon coating slurry is greater than or equal to 9% and less than or equal to 10%; The viscosity of the electrode slurry is in the range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s; the solid content of the electrode slurry is greater than or equal to 67% and less than or equal to 69%.

7. The battery aluminum foil coating device according to claim 1, wherein: The solvent system of the carbon coating slurry is the same as the solvent system of the electrode slurry.

8. The battery aluminum foil coating device according to claim 7, wherein: The solvent of the carbon coating slurry and the electrode slurry are both oily systems.

9. A coating method for battery aluminum foil, wherein: The coating method of the battery pole piece comprises at least the following steps: After the aluminum foil is unwound by the unwinding mechanism, it is introduced into the first-side coating assembly through the guide roller; The aluminum foil enters the first-side coating assembly, and the first-side coating assembly sequentially coats the first side of the aluminum foil with the carbon coating slurry and the electrode slurry, dries the coated first side of the aluminum foil, and then guides the aluminum foil to the second-side coating assembly through a guide roller; The aluminum foil enters the second-side coating assembly, and the second-side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the second side of the aluminum foil, and the second side of the coated aluminum foil is dried, and then the coated aluminum foil is introduced into the winding mechanism through the guide roller; The aluminum foil is rolled up by a rolling mechanism to complete the coating of the aluminum foil.

10. The coating method according to claim 9, wherein: The viscosity of the carbon coating slurry is in the range of greater than or equal to 30 mPa·s and less than or equal to 500 mPa·s; the solid content of the carbon coating slurry is greater than or equal to 9% and less than or equal to 10%; The viscosity of the electrode slurry is in the range of greater than or equal to 8000 mPa·s and less than or equal to 20000 mPa·s; the solid content of the electrode slurry is greater than or equal to 67% and less than or equal to 69%.

11. The coating method according to claim 9, wherein: The aluminum foil enters the first-side coating assembly, the first-side coating assembly is used to sequentially coat the first side of the aluminum foil with a carbon coating slurry and an electrode coating slurry, and the coated first side of the aluminum foil is dried, and then the aluminum foil is guided to the second-side coating assembly through a guide roller, the steps comprising: The aluminum foil enters the first carbon layer coating mechanism, the first carbon layer coating mechanism is used to coat the carbon layer coating slurry on the first surface of the aluminum foil, and then the aluminum foil is sent to the first electrode slurry coating mechanism; The aluminum foil enters the first electrode slurry coating mechanism, and the electrode slurry is coated on the first surface of the aluminum foil coated with the carbon coating slurry by the first electrode slurry coating mechanism, and then the aluminum foil is sent into the first oven; The aluminum foil enters the first oven, and the first oven is used to dry the first side of the coated aluminum foil, and then the aluminum foil is guided into the second side coating assembly through a guide roller.

12. The coating method according to claim 11, wherein The aluminum foil enters the second-side coating assembly, the second-side coating assembly is used to sequentially coat the carbon coating slurry and the electrode slurry on the second side of the aluminum foil, the second side of the coated aluminum foil is dried, and then the coated aluminum foil is introduced into the winding mechanism through the guide roller, the steps include: The aluminum foil enters the second carbon layer coating mechanism, and the second carbon layer coating mechanism is used to coat the carbon layer slurry on the second surface of the aluminum foil, and then the aluminum foil is sent to the second electrode slurry coating mechanism; The aluminum foil enters the second electrode slurry coating mechanism, and the electrode slurry is coated on the second surface of the aluminum foil coated with the carbon coating slurry by the second electrode slurry coating mechanism, and then the aluminum foil is sent to the second oven; The aluminum foil enters the second oven, and the second side of the coated aluminum foil is dried by the second oven. Then, the coated aluminum foil is introduced into the winding mechanism through the guide roller.

13. The coating method according to claim 12, wherein: The drying temperature of the first oven is lower than the drying temperature of the second oven.

14. The coating method according to claim 13, wherein: The drying temperature of the first oven is in the range of greater than or equal to 85 degrees Celsius and less than or equal to 105 degrees Celsius, and the drying time of the aluminum foil in the first oven is in the range of greater than or equal to 2 minutes and less than or equal to 4 minutes; The drying temperature of the second oven is in the range of greater than or equal to 90 degrees Celsius and less than or equal to 115 degrees Celsius, and the drying time of the aluminum foil in the second oven is in the range of greater than or equal to 2 minutes and less than or equal to 4 minutes.

15. The coating method according to claim 9, wherein: The solvent system of the carbon coating slurry is the same as the solvent system of the electrode slurry.

16. The coating method according to claim 15, wherein: The solvent of the carbon coating slurry and the electrode slurry are both oily systems.

17. The coating method according to claim 16, wherein: The electrode slurry comprises an active material, a binder, a dispersant, a conductive agent and an organic solvent, and the carbon coating slurry comprises a carbon material powder, a film-forming agent, an organic solvent and an auxiliary agent.

18. The coating method according to claim 17, wherein: The active material is lithium iron phosphate, the binder is polyvinylidene fluoride, the dispersant is YTF003 dispersant, the conductive agent is carbon nanotubes, and the organic solvent is N-methylpyrrolidone; The carbon material powder is one of carbon black and graphene, and the organic solvent is N-methylpyrrolidone.

19. The coating method according to claim 9, wherein: The coating method of the carbon coating layer slurry is gravure transfer coating, and the coating method of the electrode slurry is one of transfer coating, extrusion coating or wet coating.

20. The coating method according to claim 9, wherein: A deviation correction mechanism is provided between the first carbon layer coating mechanism and the first electrode slurry coating mechanism; And / or, a deviation correction mechanism is provided between the first oven and the second oven; And / or, a deviation correction mechanism is arranged between the second carbon layer coating mechanism and the second electrode slurry coating mechanism; And / or, a deviation correcting mechanism is arranged between the second oven and the winding mechanism.

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