Microstructure battery pole piece coating die head and coating method

Abstract

The invention provides a microstructure battery pole piece coating die head and a coating method.The microstructure battery pole piece coating die head comprises an upper die head body (1), a limiting gasket (2) and a lower die head body (3) which are sequentially stacked and fixed, and a limiting notch (4) is formed in the side, close to a lip, of the limiting gasket; a feeding channel (5) is formed in the space among the upper die head, the limiting notch and the lower die head, the lower die head is provided with a slurry buffering groove (6), the feeding channel is connected with the slurry buffering groove in a penetrating mode, and a microstructure runner (7) is arranged on the edge of the side, close to the lip opening, of the upper die head and connected with the feeding channel in a penetrating mode. The micro-structure runner is arranged on the edge of the side, close to the lip, of the upper die head, compared with the mode that a gasket with a long micro-structure runner is additionally arranged in a split mode, the micro-structure runner can be achieved through the linear cutting machining technology, the difficulty is low, the machining precision is high, and the micro-structure runner formed in the lip position is short and easy to clean.

Description

Technical Field

[0001] The present invention relates to the technical field of microstructured battery electrode coating, and particularly to a microstructured battery electrode coating die head and a coating method. Background Art

[0002] The battery electrode is one of the core components of the battery. The design and characteristics of the battery electrode structure have an important impact on the performance, stability and application range of the battery. The battery electrode is one of the core components of the battery. By optimizing the structure of the battery electrode, the electrochemical reaction, energy density and cycle life of the battery can be directly affected, which is mainly reflected in the following aspects: (1) providing a larger electron and ion conduction channel, improving the charge and discharge rate and efficiency of the battery, and affecting the efficiency of the electrochemical reaction inside the battery; (2) being able to accommodate more active materials, thereby improving the energy storage capacity of the battery and affecting the energy density of the battery; (3) reducing the expansion and contraction of the electrode material, thereby reducing the loss of the electrode material and extending the service life of the battery, and affecting the cycle life of the battery; (4) providing a larger surface area and better conductivity, enabling the battery to charge and discharge faster. Thus, it can be seen that the design and optimization of the battery electrode structure are key factors that cannot be ignored in the process of battery research and development and manufacturing. A reasonable electrode structure can improve the battery performance while meeting different application requirements, and contribute to the further innovation and development of battery technology.

[0003] The microstructured battery electrode is a specially designed battery electrode with a structure of small size and specific shape, which can optimize the electron conductivity, ion diffusion performance and reaction activity of the battery, thereby improving the performance and function of the battery. The surface microstructure of the battery electrode can achieve higher electron conductivity, ion transport performance and reaction activity in the battery, thereby improving the performance, energy density and cycle life of the battery. Microstructured electrodes are usually used to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery. However, in the existing methods for manufacturing microstructured battery electrodes, it is impossible to achieve the rapid preparation of microstructured battery electrodes, the low-cost preparation of microstructured battery electrodes, and the high-quality and lossless preparation of microstructured battery electrodes.

[0004] The Chinese patent document discloses "a laser pore-forming device for battery electrodes", with the publication number CN211804451U. This utility model punches holes in the coating of lithium-ion battery electrodes. By controlling the laser power parameters, the porosity of the electrodes can be precisely adjusted, and the rate performance of lithium-ion batteries can be accurately adjusted. A vertical translation guide rail and a horizontal translation guide rail are provided, and the laser punching mechanism can be moved to punch holes in the lithium-ion battery electrodes comprehensively and evenly. However, laser pore-forming after rolling not only wastes production capacity and increases costs, but also, due to the uncertain thickness of the electrode coating during the production process, the phenomenon of laser punching through the current collector may occur, bringing safety risks to the battery cells. In addition, the efficiency of laser processing of microstructures is low. For batch processing of products, it takes a long time, and the laser is a high-cost consumable that needs to be regularly maintained and replaced, resulting in cost waste.

[0005] The Chinese patent document discloses "a preparation process for lithium-ion battery electrodes and a gravure printing device", with the publication number CN114039025A. In the preparation process for lithium-ion battery electrodes of this invention, after coating and drying, a negative electrode paste layer is printed or sprayed on the thinned area of the negative electrode. The thickness of the negative electrode paste layer is less than 15 μm. The gravure printing device includes an engraved plate roller, on the circumferential surface of a partial shaft section of which a plurality of grooves are evenly distributed in the circumferential direction to form an engraved area; and an impression roller, which is axially parallel and axially corresponding to the engraved plate roller, and the impression roller is adapted to be connected to the engraved plate roller to complete printing. However, this technology requires the transfer of the coating through the counterpressure of the gravure roller and the rubber roller. The counterpressure method will cause other electrode defects, such as wrinkling and deformation on the surface of the electrode. In addition, if electrodes with other structural dimensions need to be coated, the gravure roller needs to be replaced, resulting in an increase in the cost of changing the model. Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a coating die head and a coating method for microstructured battery electrodes, which are used to solve the problems of low efficiency, high cost, and large loss existing in the existing preparation process of microstructured battery electrodes.

[0007] To achieve the above object and other related objects, the present invention provides a coating die head for microstructured battery electrodes, which includes an upper die head, a limiting gasket, and a lower die head that are sequentially stacked and fixed. A limiting notch is provided on one side of the limiting gasket close to the lip. A feeding channel is formed in the space between the upper die head, the limiting notch, and the lower die head. A slurry buffer tank is provided on the lower die head, and the feeding channel is connected to the slurry buffer tank in a through manner. A microstructured flow channel is provided on the edge of one side of the upper die head close to the lip, and the microstructured flow channel is connected to the feeding channel in a through manner.

[0008] In this application, by providing a microstructured flow channel on the edge of the upper die head close to the lip, compared with the method of separately setting a gasket with a longer microstructured flow channel, it can be achieved through wire cutting processing technology, with low difficulty and high processing accuracy. The length of the microstructured flow channel formed at the lip position is short, which is easy to clean. Moreover, during the coating process, it has a lower coating flow resistance, which is beneficial to improving the coating uniformity and reducing the risk of coating defects. The slurry buffer tank can provide a certain buffering effect on the large amount of slurry provided by an external feeding device, which is beneficial to improving the coating uniformity of the microstructured battery electrode sheet.

[0009] Preferably, the lower die head is further provided with a slurry inlet and a slurry outlet, and the slurry inlet and the slurry outlet are connected to the slurry buffer tank in a through manner. The above design facilitates connection with an external feeding device to achieve automatic feeding.

[0010] Preferably, the cross-section of the microstructured flow channel is a tooth-like structure, and the tooth-like structure forms a plurality of microstructured flow channel units arranged at intervals. The cross-sectional shape of the microstructured flow channel unit determines the surface morphology of the microstructured battery electrode sheet. The cross-sectional shape can be rectangular, semi-circular, trapezoidal, etc., and can be an array-type or non-array-type micro-structure, which can be set according to performance requirements.

[0011] Preferably, the slurry buffer tank is arranged along the edge of the lower die head close to the lip. The slurry buffer tank is strip-shaped, and the cross-section of the slurry buffer tank is circular. The above design is beneficial to the uniform feeding of the slurry along the lip of the coating die head of the microstructured battery electrode sheet, improving the coating uniformity.

[0012] Preferably, the limiting notch is adapted to the slurry buffer tank.

[0013] More preferably, the limiting notch forms a constricted structure towards the lip direction, which can form a buffering effect during feeding and improve the coating uniformity.

[0014] The present invention also provides a method for coating a microstructured battery electrode sheet. The current collector is brought into contact with the lip of the microstructured battery electrode sheet coating die head as described above. An external feeding device is used to supply coating slurry to the slurry buffer tank. The extrusion coating method is adopted to make the coating slurry flow from the slurry buffer tank to the feeding channel and then flow out through the microstructured flow channel, and the current collector is microstructurally coated to obtain a microstructured battery electrode sheet. The microstructured battery electrode sheet sequentially includes a current collector, a slurry base layer, and a microstructured coating layer.

[0015] Compared with the prior art in which the slurry is first coated and then a microstructured coating is formed on the slurry by laser etching or templating, the technical solution of the present invention greatly simplifies the process steps, realizes the synchronous coating of the microstructures in a one-step method directly in the coating process, and has a simple equipment structure and is easy to implement. Compared with the traditional microstructured electrode manufacturing process, the microstructured battery electrode coating method of the present invention can be directly installed on a conventional electrode coating production line based on the microstructured battery electrode coating die head for coating production, which can greatly reduce the production cost. At the same time, since the microstructured battery electrode coating die head of the present invention still uses the extrusion coating method, it has the same coating efficiency as a conventional coating line. Thus, it can be seen that the process can realize the rapid preparation of microstructured electrodes.

[0016] Preferably, the coating thickness of the slurry base layer of the microstructured battery electrode is controlled by adjusting the thickness of the limit gasket.

[0017] Preferably, the coating width of the slurry base layer of the microstructured battery electrode is controlled by adjusting the length of the limit notch of the limit gasket.

[0018] Preferably, the morphology of the microstructured coating of the microstructured battery electrode is adjusted by adjusting the shape of the microstructures.

[0019] Preferably, the cross-section of the microstructured flow channel is a toothed structure, and the toothed structure forms a plurality of spaced microstructured flow channel units, and the coating thickness of the microstructured coating is controlled by adjusting the height of the microstructured flow channel units.

[0020] The present invention also provides a microstructured battery electrode obtained by the above microstructured battery electrode coating method. The coating layer of this microstructured battery electrode is uniform, has good performance, and is expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery.

[0021] Preferably, the microstructured battery electrode sequentially includes a current collector, a slurry base layer, and a microstructured coating.

[0022] As described above, the microstructured battery electrode coating die head and coating method of the present invention have the following beneficial effects: (1) By setting a microstructured flow channel on the edge of the upper die head close to the lip, compared with the way of separately setting a gasket with a relatively long microstructured flow channel, it can be realized by wire cutting processing technology, with low difficulty and high processing accuracy. The length of the microstructured flow channel formed at the lip position is short, easy to clean, and during the coating process, it has a low coating flow resistance, which is beneficial to improving the coating uniformity and reducing the risk of coating defects; (2) Compared with the prior art in which the slurry is coated first and then the microstructured coating is formed on the slurry by laser etching or templating methods, the process steps are greatly simplified, and the coating of the microstructures can be synchronously completed in one step directly in the coating process. The extrusion coating method is adopted, and the coating efficiency is the same as that of a conventional coating line, enabling the rapid preparation of microstructured electrode sheets. (3) The coating layer of the microstructured battery electrode sheet prepared in this application has good uniformity, which is expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery. Description of the Drawings

[0023] Figure 1 Schematic structural diagram of the coating die head of the microstructured battery electrode sheet shown in Example 1.

[0024] Figure 2 Shown as Figure 1 exploded structural diagram.

[0025] Figure 3 Shown as Figure 1 top view.

[0026] Figure 4 Shown as Figure 3 enlarged view at A in

[0027] Figure 5 Shown as Figure 3 cross-sectional view in the M-M direction in

[0028] Figure 6 Shown as Figure 5 enlarged view at B in

[0029] Figure 7 Schematic structural diagram of the upper die head shown.

[0030] Figure 8 Shown as Figure 7 top view.

[0031] Figure 9 Shown as Figure 8 enlarged view at C in

[0032] Figure 10 Schematic structural diagram of the limit gasket shown.

[0033] Figure 11 Schematic structural diagram of the lower die head shown.

[0034] Figure 12 Top view of the microstructured battery electrode sheet shown.

[0035] Figure 13 Shown as Figure 12 front view.

[0036] Figure 14 Shown as Figure 13 The enlarged view at D in

[0037] Figure 15 Shown as the physical picture of the microstructured battery electrode sheet prepared in Example 1.

[0038] Figure 16 Shown as the schematic structural diagram of the upper die head in the coating die head of the microstructured battery electrode sheet in Example 2.

[0039] Figure 17 Shown as Figure 16 The enlarged view at E in

[0040] Figure 18 Shown as the schematic structural diagram of the upper die head in the coating die head of the microstructured battery electrode sheet in Example 3.

[0041] Figure 19 Shown as Figure 18 The enlarged view at F in

[0042] Explanation of the reference numerals in the drawings 1 Upper die head 2 Limit gasket 3 Lower die head 4 Limit notch 5 Feeding channel 6 Slurry buffer tank 7 Microstructured flow channel 8 Slurry inlet 9 Slurry outlet 10 Microstructured flow channel unit 11 Current collector 12 Slurry base layer 13 Microstructured coating 14 Locking bolt 15 Die head assembly hole 16 Gasket assembly hole Detailed implementation manners

[0043] In order to make the invention objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0044] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0045] Unless otherwise clearly defined and limited, the terms "connected", "fixed", "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and can be the connection inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0046] Embodiment 1 As Figure 1 and Figure 2 shown, the embodiment of the present application provides a microstructured battery electrode coating die head, which includes an upper die head 1, a limiting gasket 2 and a lower die head 3 that are sequentially stacked and fixed. A limiting notch 4 is provided on one side of the limiting gasket close to the lip. Combining Figure 3 , Figure 5 and Figure 6 , a feeding channel 5 is formed in the space between the upper die head, the limiting notch and the lower die head. The lower die head is provided with a slurry inlet 8, a slurry outlet 9 and a slurry buffer tank 6. The slurry inlet and the slurry outlet are connected to the slurry buffer tank in a through manner. The feeding channel is connected to the slurry buffer tank in a through manner. On one side edge of the upper die head close to the lip, there is a microstructured flow channel 7. Combining Figure 3 , Figure 4 , Figure 7 , Figure 8 and Figure 9 , the cross-section of the microstructured flow channel is a tooth-shaped structure. The tooth-shaped structure forms a number of microstructured flow channel units 10 arranged at intervals. The cross-section of the microstructured flow channel unit is a rectangular structure; the microstructured flow channel is connected to the feeding channel in a through manner. Combining Figure 3 , Figure 5 , Figure 6 and Figure 11 , the slurry buffer tank is arranged along one side edge of the lower die head close to the lip. The slurry buffer tank is strip-shaped. The cross-section of the slurry buffer tank is circular. The limiting notch is adapted to the slurry buffer tank. As Figure 10As shown, the limiting notch forms a necking structure towards the lip direction. The upper die head 1 and the lower die head 3 are correspondingly provided with 8 die head assembly holes 15. The limiting gasket 2 is provided with gasket assembly holes corresponding to the die head assembly holes. The upper die head 1, the limiting gasket 2 and the lower die head 3 are superposed and fixed by successively passing locking bolts through the die head assembly holes 15 and the gasket assembly holes 16. The upper die head and the lower die head are provided with inclined surface structures near the lip.

[0047] This embodiment also provides a microstructured battery electrode coating method based on the above microstructured battery electrode coating die head, including the following steps: An external feeding device is used to supply coating slurry to the slurry buffer tank. The coating slurry is made to flow from the slurry buffer tank to the feeding channel by means of extrusion coating, and then flows out through the microstructured channel to perform microstructured coating on the current collector. The coating thickness of the slurry base layer of the microstructured battery electrode is controlled by adjusting the thickness of the limiting gasket; the coating width of the slurry base layer of the microstructured battery electrode is controlled by adjusting the length of the limiting notch of the limiting gasket; the morphology of the microstructured coating of the microstructured battery electrode is adjusted by adjusting the shape of the microstructures; the coating thickness of the microstructured coating is controlled by adjusting the height of the microstructured channel unit. After coating is completed, it is dried to obtain a microstructured battery electrode.

[0048] Combined with Figure 12 , Figure 13 and Figure 14 , the microstructured battery electrode prepared in this embodiment successively includes a current collector 11, a slurry base layer 12 and a microstructured coating 13. The physical diagram of the microstructured battery electrode prepared in this embodiment is as shown in Figure 15 As shown, it can be seen from the figure that the surface coating of the microstructured battery electrode obtained by using the microstructured battery electrode coating die head and coating method of this embodiment has good uniformity, the microstructures are clearly visible, and it is expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery.

[0049] Embodiment 2 As shown in Figure 16 and Figure 17 , the difference between Embodiment 2 and Embodiment 1 is that the structure of the microstructured battery electrode coating die head is different. Specifically, the cross-sectional shape of the microstructured channel unit is different. In this embodiment, an isosceles trapezoid is adopted, and the other components and connection relationships are exactly the same.

[0050] The surface coating of the microstructured battery electrode prepared in this embodiment has good uniformity, and the microstructures are raised structures with an isosceles trapezoid cross-section. It is expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery.

[0051] Embodiment 3 As shown in Figure 18 andFigure 19 As shown in the figure, the difference between Example 3 and Example 1 lies in the different structures of the coating die head for the microstructured battery electrode sheet. Specifically, the cross-sectional shape of the microstructured flow channel unit is different. In this example, a semicircle is adopted, and the other components and their connection relationships are exactly the same.

[0052] The surface coating of the microstructured battery electrode sheet prepared in this example has good uniformity. The microstructures are convex structures with a semicircular cross-section, which are expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery.

[0053] In summary, by setting the microstructured flow channel on the edge of the upper die head close to the lip, compared with the method of separately setting a gasket with a longer microstructured flow channel, the present invention can be realized through wire cutting processing technology, with low difficulty and high processing accuracy. The length of the microstructured flow channel formed at the lip position is short, which is easy to clean. During the coating process, it has a low coating flow resistance, which is beneficial to improving the coating uniformity and reducing the risk of coating defects. Compared with the prior art in which the slurry is first coated and then a microstructured coating is formed on the slurry by laser etching or template method, the process steps are greatly simplified, and the microstructured coating can be directly completed in one step during the coating process by extrusion coating. It has the same coating efficiency as a conventional coating line and can realize the rapid preparation of the microstructured electrode sheet. The coating layer of the obtained microstructured battery electrode sheet has good uniformity, is expected to improve the charge and discharge rate of the battery, enhance the electrolyte permeability, and increase the effective surface area of the battery. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0054] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A coating die for a microstructured battery electrode sheet, characterized in that, It includes an upper die head (1), a limit spacer (2) and a lower die head (3) which are successively laminated and fixed. A limit notch (4) is provided on one side of the limit spacer close to the lip. A feeding channel (5) is formed in the space between the upper die head, the limit notch and the lower die head. The lower die head is provided with a slurry buffer tank (6). The feeding channel is connected to the slurry buffer tank in a through manner. A microstructured flow channel (7) is provided on one side edge of the upper die head close to the lip. The microstructured flow channel is connected to the feeding channel in a through manner.

2. The coating die for a microstructured battery electrode sheet according to claim 1, characterized in that: The lower die head is further provided with a slurry inlet (8) and a slurry outlet (9). The slurry inlet and the slurry outlet are connected to the slurry buffer tank in a through manner.

3. The coating die for a microstructured battery electrode sheet according to claim 1, characterized in that: The cross-section of the microstructured flow channel is a toothed structure, and the toothed structure forms a number of microstructured flow channel units (10) arranged at intervals.

4. The coating die for a microstructured battery electrode sheet according to claim 1, characterized in that: The slurry buffer tank is arranged along one side edge of the lower die head close to the lip. The slurry buffer tank is strip-shaped, and the cross-section of the slurry buffer tank is circular.

5. The coating die for a microstructured battery electrode sheet according to claim 4, characterized in that: The limit notch is adapted to the slurry buffer tank, and the limit notch forms a constricted structure towards the lip direction.

6. A method for coating a microstructured battery electrode sheet, characterized in that: The current collector is brought into contact with the lip of the microstructured battery electrode coating die head as described in any one of claims 1 to 5. An external feeding device is used to supply coating slurry to the slurry buffer tank. The extrusion coating method is adopted to make the coating slurry flow from the slurry buffer tank to the feeding channel, and then flow out from the microstructured flow channel to perform microstructured coating on the current collector, obtaining a microstructured battery electrode. The microstructured battery electrode successively includes a current collector, a slurry base layer and a microstructured coating.

7. The method for coating a microstructured battery electrode sheet according to claim 6, characterized in that: The coating thickness of the slurry base layer of the microstructured battery electrode is controlled by adjusting the thickness of the limit spacer; the coating width of the slurry base layer of the microstructured battery electrode is controlled by adjusting the length of the limit notch of the limit spacer.

8. The method for coating a microstructured battery electrode sheet according to claim 6, characterized in that: The morphology of the microstructured coating of the microstructured battery electrode is adjusted by adjusting the shape of the microstructures.

9. The method for coating a microstructured battery electrode sheet according to claim 6, characterized in that: The cross-section of the microstructured flow channel is a toothed structure, and the toothed structure forms a number of microstructured flow channel units arranged at intervals. The coating thickness of the microstructured coating is controlled by adjusting the height of the microstructured flow channel units.

10. A microstructured battery electrode sheet obtained by the method for coating a microstructured battery electrode sheet according to any one of claims 6 to 9.

11. The microstructured battery electrode sheet according to claim 10, characterized in that: The microstructured battery electrode successively includes a current collector (11), a slurry base layer (12) and a microstructured coating (13).

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