Coating die head and coating equipment

Abstract

The utility model belongs to the technical field of coating equipment, and particularly relates to a coating die head and coating equipment. The die head comprises an upper die head, a lower die head and a slurry backflow runner inlet, and is characterized in that a slit outlet is formed by a slit between the front end of the upper die head and the front end of the lower die head, and a containing cavity formed between the upper die head and the lower die head can contain coating slurry. And the slurry backflow runner inlet is positioned on one side or two sides of the slit outlet, is close to the slit outlet and is connected with the accommodating cavity. The inlet of the slurry backflow runner is added to be close to the outlet of the slit, so that the slurry is always kept in a state of consistent surface density before being coated. The slurry meeting the coating size is extruded and coated on the base material at the moment that the slurry is coated on the base material, and the slurry not meeting the size requirement flows away through the inlet of the slurry backflow runner, so that the risk that large particles in the slurry block a die head is reduced, and the density consistency of the slurry coated on a pole piece is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of coating equipment, and in particular relates to a coating die head and coating equipment. Background Art

[0002] The manufacturing process of lithium battery cells includes slurry preparation, coating, rolling, slitting, assembly, welding, packaging, liquid injection and formation, among which the coating process is the process of uniformly coating the suspension on the pole piece, wetting, leveling and drying. In the production process of lithium batteries, slit extrusion coating is the most widely used, which has the advantages of quantitative, high speed and stability. The main device of extrusion coating consists of a slurry storage tank, a die head and a gasket. During the coating process, the positive and negative electrode slurry of the lithium battery flows from the storage tank through the inner cavity of the die head, and flows out of the gap formed by the die head and the gasket, and is applied to the moving positive and negative electrode aluminum foil / copper foil to form positive and negative electrode coatings. The design of the gasket mainly includes thickness, length and width, and chamfer of the gasket at the slurry outlet. The stability and operability of the coating process and the consistency of the surface density will affect the yield of subsequent processes and the performance of the final product. Its main impacts are the following two points: 1. Determine whether subsequent products can be effectively divided and grouped - poor surface density consistency will inevitably screen out many batteries with excessive surface density during the division and grouping process, which will lead to low material utilization and increase production costs; 2. Determine the long-cycle capacity retention rate of the battery cell series-parallel module - in a single battery cell, poor surface density consistency will lead to the positive and negative electrode capacities not being effectively utilized, resulting in low final capacity or lithium precipitation, and severe safety problems. After series and parallel connection, poor surface density consistency will gradually cause overcharge and over-discharge of low-capacity batteries, which is not only not conducive to the utilization of capacity, but also causes safety failures of single batteries. Utility Model Content

[0003] The utility model provides a coating die head, reduces the risk of large particles in the slurry blocking the die head, and improves the density consistency of the slurry after coating on the pole piece.

[0004] To achieve this purpose, the utility model adopts the following technical solutions:

[0005] The utility model discloses a coating die head, comprising an upper die head, a lower die head and a slurry return flow channel inlet, and is characterized in that a slit outlet is formed by a gap between the front ends of the upper die head and the lower die head, a containing cavity formed between the upper die head and the lower die head can contain coating slurry, and the slurry return flow channel inlet is located on one side or both sides of the slit outlet and is close to the slit outlet and is connected to the containing cavity.

[0006] Optionally, the slurry reflux channel inlet is arranged on the upper die head and / or the lower die head.

[0007] Optionally, the number of the slurry return channel inlets is one or more.

[0008] Furthermore, the die head also includes a slurry reflux channel and a slurry reflux channel outlet, and two ends of the slurry reflux channel are respectively connected to the slurry reflux channel inlet and the slurry reflux channel outlet.

[0009] Furthermore, the slurry reflux channel is arranged in the inner wall of the lower die head.

[0010] Furthermore, the inlet of the slurry return channel is arranged on the inner wall of the lower die head.

[0011] Optionally, the inlet of the slurry return flow channel is a U-shaped groove.

[0012] Optionally, the outer edge of the slit outlet is provided with a chamfer, and the chamfer is used to improve the slurry flow to eliminate the flow dead zone and the pole piece bulging phenomenon.

[0013] Optionally, the upper die head is connected to the lower die head via threads.

[0014] By using a coating die head of the utility model, at the moment when the slurry is coated on the substrate, the slurry that meets the coating size is extruded and coated on the substrate, and the slurry that does not meet the size requirements flows away through the inlet of the slurry return flow channel, thereby reducing the risk of large particles in the slurry clogging the die head and improving the density consistency of the slurry after coating on the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following drawings of the embodiments of the present invention are used as a part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principle of the present invention.

[0016] Figure 1 This is a schematic diagram of the upper die head

[0017] Figure 2 This is the schematic diagram of the lower die head

[0018] Figure 3 This is a schematic diagram of the die head

[0019] In the figure: 1. upper die head; 2. lower die head; 21. slurry return flow channel inlet; 22. slurry return flow channel; 23. slurry return flow channel outlet; 3. chamfer. DETAILED DESCRIPTION

[0020] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the utility model. However, it is obvious to those skilled in the art that the embodiments of the utility model can be implemented without one or more of these details. In other examples, in order to avoid confusion with the embodiments of the utility model, some technical features known in the art are not described. The utility model is further described in detail below in conjunction with the accompanying drawings and examples. It is understood that the specific embodiments described herein are only used to explain the utility model, rather than to limit the utility model. It should also be noted that, for ease of description, only parts related to the utility model are shown in the accompanying drawings, not all structures. In the description of the utility model, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense.

[0021] In the description of this embodiment, the terms "both sides", "upper", "lower", and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model.

[0022] In order to improve the density consistency of the slurry after coating on the pole piece, this embodiment provides a coating die head.

[0023] See also Figure 1-3 As shown, the coating die head includes an upper die head 1, a lower die head 2, and a slurry return flow channel inlet 21. A slit outlet is formed by a gap between the front ends of the upper die head 1 and the lower die head 2. The slit outlet is suitable for slurry circulation and is a slurry outflow channel during coating. The accommodating cavity formed between the upper die head 1 and the lower die head 2 can accommodate the coating slurry. The slurry return flow channel inlet 21 is located on one side or both sides of the slit outlet and is close to the slit outlet and connected to the accommodating cavity. The one side or both sides are located perpendicular to the direction of slurry outflow from the slit outlet.

[0024] Optionally, the slurry reflux channel inlet 21 is disposed on the upper die head 1 or the lower die head 2 , or is disposed on both the upper die head 1 and the lower die head 2 .

[0025] Optionally, the number of the slurry return channel inlet 21 is one or more.

[0026] Furthermore, the die head further comprises a slurry return flow channel 22 and a slurry return flow channel outlet 23 , and two ends of the slurry return flow channel 22 are respectively connected to the slurry return flow channel inlet 21 and the slurry return flow channel outlet 23 .

[0027] In this embodiment, the slurry reflux channel 22 is disposed in the inner wall of the lower die head 2 .

[0028] In this embodiment, the slurry return flow channel inlet 21 is arranged on the inner wall of the lower die head 2, and two slurry return flow channel inlets 21 are arranged, which are arranged on both sides of the slit outlet and are connected to the slurry return flow channel 22. During the coating operation, the slurry flows out from the slit outlet to coat the pole piece, and at the same time, the slurry on both sides of the slit outlet flows away through the slurry return flow channel outlet 23, and then flows to the recovery device through the slurry return flow channel 22 and the slurry return flow channel outlet 23, so that the slurry flowing out of the slit outlet can flow out evenly, reducing the risk of large particles in the slurry clogging the die head, and improving the density consistency of the slurry after coating on the pole piece.

[0029] In this embodiment, the slurry return channel inlet 21 is a U-shaped groove.

[0030] Optionally, the outer edge of the slit outlet is provided with a chamfer 3, and the chamfer 3 is used to improve the flow of the slurry to eliminate the flow dead zone and the bulging edge of the electrode. The coated slurry flows out after the chamfer, and the chamfer is closer to the slurry. An active material layer with a thinning area with uniform thinning thickness can be formed during the slurry coating process. The thinning area enables the electrolyte to quickly penetrate and infiltrate the entire electrode, thereby reducing the infiltration time, ensuring that there is sufficient electrolyte in the middle of the battery cell, reducing the temperature of the middle section, and improving the consistency of the electrode attenuation, thereby reducing the polarization phenomenon of the battery during the charging and discharging process, reducing the internal resistance of the battery, thereby increasing the battery discharge rate, and improving the battery cycle performance.

[0031] Optionally, the upper die head 1 and the lower die head 2 are connected via threads.

[0032] In summary, the utility model provides a coating die head and coating equipment that can improve battery performance.

[0033] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A coating die head, comprising an upper die head, a lower die head, and a slurry return flow channel inlet, characterized in that: The gap between the front ends of the upper die head and the lower die head forms a slit outlet, and the accommodating cavity formed between the upper die head and the lower die head can accommodate the coating slurry. The inlet of the slurry return channel is located on one side or both sides of the slit outlet and is close to the slit outlet and connected to the accommodating cavity.

2. The die head according to claim 1, characterized in that: The slurry reflux channel inlet is arranged on the upper die head and / or the lower die head.

3. The die head according to claim 2, characterized in that: The number of the slurry return flow channel inlets is one or more.

4. The die head according to claim 2, characterized in that The die head also includes a slurry reflux channel and a slurry reflux channel outlet. Both ends of the slurry reflux channel are respectively connected to the slurry reflux channel inlet and the slurry reflux channel outlet.

5. The die head according to claim 4, characterized in that: The slurry reflux channel is arranged in the inner wall of the lower die head.

6. The die head according to claim 5, characterized in that The inlet of the slurry return flow channel is arranged on the inner wall of the lower die head.

7. The die head according to claim 6, characterized in that The inlet of the slurry return flow channel is a U-shaped groove.

8. The die head according to claim 1, characterized in that The outer edge of the slit outlet is provided with a chamfer, and the chamfer is used to improve the slurry flow to eliminate the flow dead zone and the pole piece bulging phenomenon.

9. The die head according to claim 1, characterized in that: The upper die head is connected to the lower die head via threads.

10. A coating device, characterized in that: include: The coating die according to any one of claims 1 to 9.

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