Pole piece coating device

Abstract

The utility model relates to the technical field of pole piece coating, and provides a pole piece coating device which comprises a coating mold and a thinning gasket, a slurry area communicated to the lower end of the coating mold is formed on the coating mold, and the slurry area is used for allowing slurry to flow out; the thinning gasket is arranged in the slurry area and located in the middle of the slurry area. By arranging the thinning gasket in the middle of the slurry area, when the positive plate is coated, the middle thinning groove can be used for thinning the coating area in the middle of the positive plate, and as the upper groove wall of the middle thinning groove is V-shaped, when the positive plate is coated, the coating slurry in the middle of the positive plate can be inclined in a V-shaped manner; therefore, the thickness of the middle area of the formed positive plate is obviously reduced, the middle thinned area of the positive plate can correspond to the side thinned area of the negative tab, the abnormal condition of lithium precipitation during use is prevented, and the positive plate is convenient to use.

Description

Technical Field

[0001] This utility model relates to the field of electrode coating technology, and in particular to an electrode coating device. Background Technology

[0002] Electrode coating refers to the process of uniformly coating active materials onto an electrode substrate (such as aluminum foil or copper foil) during battery manufacturing. For cylindrical lithium-ion batteries, the positive and negative electrode tabs are located at both ends of the battery. This can easily lead to a situation where the thinned area on the negative electrode tab side corresponds to the normal material area on the positive electrode non-tab side. Because the positive electrode capacity exceeds the negative electrode's tolerance limit, an abnormal "lithium plating" phenomenon occurs in the thinned area on the negative electrode tab side after charging and discharging. This phenomenon is often avoided by reducing the thinned area on the negative electrode during electrode coating.

[0003] The invention disclosed in CN118106188B proposes a battery electrode coating apparatus, comprising: a first conveying roller and a second conveying roller for conveying electrode strips; a coating die head disposed adjacent to the first conveying roller for applying a single layer of coating to the electrode strip at the first conveying roller; and an oven disposed between the first and second conveying rollers for baking the coated electrode strip. However, the coating die used in the above-mentioned battery electrode coating apparatus is a conventional coating die. Conventional coating dies only have raised chamfers designed at the edges of the die, so when the slurry flows out, only a thinning area is formed at the edges, and it is impossible to form a thinning area in the middle of the positive electrode when coating the positive electrode. This leads to the abnormal situation of "lithium plating" still occurring in actual use. Therefore, this solution proposes an electrode coating apparatus to solve the above problems. Utility Model Content

[0004] In view of this, the present invention proposes an electrode coating device to solve the problem of "lithium plating" abnormality in the thinning area on the negative electrode tab side after charging and discharging.

[0005] The technical solution of this utility model is achieved as follows: This utility model provides an electrode coating device, including a coating mold and a thinning pad, wherein,

[0006] A slurry zone is formed on the coating mold and extends to the lower end of the coating mold. The slurry zone is used for slurry outflow.

[0007] A thinning pad is disposed within the slurry zone and located in the middle of the slurry zone. The lower end of the thinning pad is flush with the lower end of the coating mold. A central thinning groove is formed on the front side of the thinning pad. The central thinning groove connects to the lower end of the thinning pad and connects to the opposite sides of the thinning pad in the width direction of the coating mold. The upper wall of the central thinning groove is a V-shaped groove wall.

[0008] Based on the above technical solutions, preferably, the height of the upper end of the intermediate thinning groove from the lower end of the thinning pad is a, and the height of the middle part of the upper groove wall from the lower end of the thinning pad is b, and 3mm≤a≤5mm, 1mm≤b≤3mm.

[0009] Based on the above technical solutions, preferably, the width of the thinned gasket is c, and 3mm≤c≤5mm.

[0010] Based on the above technical solutions, preferably, the thickness of the thinned gasket is d, and the depth of the intermediate thinning groove is e, where d = 0.8 mm, d / 2 ≤ e ≤ 5d / 8.

[0011] Based on the above technical solutions, the preferred values ​​are d = 0.8 mm and 0.4 mm ≤ e ≤ 0.5 mm.

[0012] Based on the above technical solutions, preferably, the slurry flowing out of the slurry zone includes a positive electrode material, a conductive agent, and a binder, and the mass ratio of the positive electrode material, the conductive agent, and the binder is 95:3:2.

[0013] Based on the above technical solutions, preferably, the coating mold includes a slurry outlet wall, and the slurry outlet of the slurry area is formed between the two slurry outlet walls. A side-shaving groove is provided on the opposite side of the two slurry outlet walls. The side-shaving groove has a triangular cross-section and connects to the bottom of the slurry outlet wall.

[0014] Based on the above technical solutions, preferably, the cross-section of the side thinning groove is a right-angled triangle, and the lengths of the three sides of the cross-section of the side thinning groove are 2mm, 3mm and 5mm respectively, and the groove depth of the side thinning groove is adapted to the groove depth of the middle thinning groove.

[0015] The electrode coating device of this invention has the following advantages over the prior art:

[0016] By setting a thinning pad in the middle of the slurry area, when coating the positive electrode sheet, the thinning groove in the middle can form a V-shaped inclined groove in the middle of the coating slurry of the positive electrode sheet. By cutting the positive electrode sheet from the V-shaped groove of the coating slurry in the middle of the positive electrode sheet to form two positive electrode sheets, the V-shaped groove of the coating slurry after cutting is in a thinned state. In this way, after connecting the positive electrode sheet and the negative electrode sheet, the cut part of the positive electrode sheet can correspond to the thinned area of ​​the tab of the negative electrode sheet, thereby preventing the abnormal situation of "lithium plating" during use and facilitating use. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view of the electrode coating device of this utility model;

[0019] Figure 2 The electrode coating device of this utility model Figure 1 An enlarged view of point A is shown below;

[0020] Figure 3 This is a perspective view of the electrode coating device of this utility model;

[0021] Figure 4 The electrode coating device of this utility model Figure 3 An enlarged view of point B is shown below;

[0022] Figure 5 This is a schematic diagram of an electrode structure formed by the electrode coating device of this utility model.

[0023] In the diagram: 1. Coating mold; 11. Slurry zone; 12. Slurry outlet wall; 121. Side thinning groove; 2. Thinning pad; 21. Middle thinning groove. Detailed Implementation

[0024] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0025] like Figures 1-5 As shown, the electrode coating apparatus of this utility model includes a coating mold 1 and a thinning pad 2. The coating mold 1 has a slurry area 11 connected to the lower end of the coating mold 1, which is used for slurry outflow. The thinning pad 2 is disposed in the slurry area 11 and located in the middle of the slurry area 11. The lower end of the thinning pad 2 is flush with the lower end of the coating mold 1. A middle thinning groove 21 is provided on the front side of the thinning pad 2. The middle thinning groove 21 is connected to the lower end of the thinning pad 2 and is connected to the opposite sides of the thinning pad 2 in the width direction of the coating mold 1. The upper groove wall of the middle thinning groove 21 is a V-shaped groove wall.

[0026] Figure 1 The X direction is the width direction of the coating mold 1.

[0027] In practice, the positive electrode sheet to be coated is located below the coating mold 1. The slurry in the slurry area 11 flows out from the slurry outlet, thus completing the coating process of the positive electrode sheet. Since a thinning pad 2 is provided in the middle of the slurry area 11, when coating the positive electrode sheet, the middle thinning groove 21 can form a V-shaped inclined groove in the middle of the coating slurry of the positive electrode sheet. By cutting the positive electrode sheet from the V-shaped groove of the coating slurry in the middle of the positive electrode sheet to form two positive electrode sheets, the V-shaped groove of the coating slurry after cutting is in a thinned state. In this way, after connecting the positive electrode sheet and the negative electrode sheet, the cut part of the positive electrode sheet can correspond to the thinned area of ​​the tab of the negative electrode sheet, thereby preventing the abnormal situation of "lithium plating" during use and facilitating use.

[0028] In a preferred embodiment, the height of the upper end of the intermediate thinning groove 21 from the lower end of the thinning pad 2 is a, and the height of the middle part of the upper wall of the intermediate thinning groove 21 from the lower end of the thinning pad 2 is b, and 3mm≤a≤5mm, 1mm≤b≤3mm.

[0029] This design keeps the thickness of the upper wall of the thinning groove 21 at around 2mm, resulting in a V-shaped area of ​​slurry in the center of the produced positive electrode sheet with a height of 2mm. This conforms to the conventional setting of a positive electrode sheet slurry height of around 3mm, while also ensuring that the lower part of the positive electrode sheet slurry can be integrated, guaranteeing coating strength and stability.

[0030] In a preferred embodiment, the width of the thinned gasket 2 is c, and 3mm≤c≤5mm.

[0031] This design ensures that the opening size of the V-shaped area of ​​the coating slurry in the middle of the produced positive electrode sheet is between 3-5mm. This allows the coating slurry of the formed positive electrode sheet to maintain its performance while also ensuring that the V-shaped area of ​​the coating slurry in the middle of the formed positive electrode sheet can correspond to the side thinning area of ​​the negative electrode tab after connection.

[0032] In a preferred embodiment, the thickness of the thinned pad 2 is d, and the depth of the intermediate thinning groove 21 is e, where d = 0.8 mm, d / 2 ≤ e ≤ 5d / 8.

[0033] Preferably, d = 0.8 mm, and 0.4 mm ≤ e ≤ 0.5 mm.

[0034] This design allows the coating thickness of the formed positive electrode sheet to be between 0.4-0.5 mm. Simultaneously, by setting the thickness of the thinning pad 2 to 0.8 mm, sufficient rigidity is provided to the thinning pad 2, preventing deformation caused by pressure changes during the coating process. Furthermore, the moderate thickness also helps control the uniformity of the coating.

[0035] In a preferred embodiment, the slurry flowing out of the slurry zone 11 includes a positive electrode material, a conductive agent, and a binder, and the mass ratio of the positive electrode material, the conductive agent, and the binder is 95:3:2.

[0036] In practice, the positive electrode material can be NCM811, the conductive agent can be acetylene black, and the binder can be PVDF. By setting the positive electrode material to account for as much as 95%, the energy density of the battery is ensured. The positive electrode material is usually the main component for energy storage in lithium-ion batteries, and a higher proportion helps to improve the overall energy output of the battery.

[0037] In a preferred embodiment, the coating mold 1 includes a slurry outlet wall 12, and the slurry outlet of the slurry zone 11 is formed between the two slurry outlet walls 12. A side-cutting groove 121 is provided on the opposite side of the two slurry outlet walls 12. The side-cutting groove 121 has a triangular cross section and is connected to the bottom of the slurry outlet wall 12.

[0038] The cross-section of the side-cutting groove 121 is a right-angled triangle, and the lengths of the three sides of the cross-section of the side-cutting groove 121 are 2mm, 3mm and 5mm respectively. The groove depth of the side-cutting groove 121 is matched with the groove depth of the middle-cutting groove 21.

[0039] This design allows the sides of the formed positive electrode coating slurry to be inclined, conforming to the current side forming process of positive electrode coating slurry. The inclined sides enable a smooth thinning transition between the positive electrode tab (foil area) and the positive electrode coating area. Simultaneously, by setting the three side lengths of the side-shaving groove 121 to be 2mm, 3mm, and 5mm respectively, a thinning width of 7-10mm and a thinning thickness of 30-40µm are guaranteed at the edge of the electrode after coating, meeting the production requirements of cylindrical batteries.

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A pole piece coating device characterized by: The application relates to a coating die (1) and a thinning gasket (2), wherein, The coating die (1) is provided with a slurry area (11) communicated with the lower end of the coating die (1), and the slurry area (11) is used for slurry outflow; The thinning gasket (2) is arranged in the slurry area (11) and located at the middle of the slurry area (11), the lower end of the thinning gasket (2) is flush with the lower end of the coating die (1), the front side of the thinning gasket (2) is provided with a middle thinning groove (21), the middle thinning groove (21) is communicated with the lower end of the thinning gasket (2) and communicated with the opposite sides of the thinning gasket (2) in the width direction of the coating die (1), and the upper groove wall of the middle thinning groove (21) is a V-shaped groove wall.

2. The pole piece coating apparatus of claim 1, wherein: The height of the upper groove wall end of the middle thinning groove (21) from the lower end of the thinning gasket (2) is a, the height of the middle part of the upper groove wall of the middle thinning groove (21) from the lower end of the thinning gasket (2) is b, and 3mm<=a<=5mm and 1mm<=b<=3mm.

3. The pole piece coating apparatus of claim 1, wherein: The width of the thinning gasket (2) is c, and 3mm<=c<=5mm.

4. The pole piece coating apparatus of claim 1, wherein: The thickness of the thinning gasket (2) is d, and the groove depth of the middle thinning groove (21) is e, and d=0.8mm, d / 2<=e<=5d / 8.

5. The pole piece coating apparatus of claim 4, wherein: d=0.8mm, 0.4mm<=e<=0.5mm.

6. The pole piece coating apparatus of claim 1, wherein: The slurry outflowed from the slurry area (11) comprises positive electrode material, conductive agent and binder, and the mass ratio of the positive electrode material, the conductive agent and the binder is 95:3:

2.

7. The pole piece coating apparatus of claim 4, wherein: The coating die (1) comprises slurry outlet walls (12), the slurry outlet of the slurry area (11) is formed between two slurry outlet walls (12), and the opposite side of the two slurry outlet walls (12) is provided with a side thinning groove (121), the cross section of the side thinning groove (121) is triangular, and the side thinning groove (121) is communicated with the lower part of the slurry outlet wall (12).

8. The pole piece coating apparatus of claim 7, wherein: The cross section of the side thinning groove (121) is a right-angled triangle, the lengths of the three sides of the cross section of the side thinning groove (121) are 2mm, 3mm and 5mm respectively, and the groove depth of the side thinning groove (121) is matched with the groove depth of the middle thinning groove (21).

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