Coating device

Abstract

A coating device, comprising a corona unit and a coating unit which are sequentially arranged in a foil conveying direction. The corona unit has a discharge portion arranged towards the surface of the foil, and the discharge portion is used for carrying out corona treatment on the surface of the foil; the coating unit has a coating die, and the coating die is used for coating the surface of the foil having experienced corona treatment with a slurry. According to the coating device, the corona unit arranged upstream of the coating unit can perform corona treatment on the surface of the foil, and then coating is carried out, so that oil stains on the surface of the foil can be removed and the dyne value of the surface of the foil is improved; moreover, electrode sheets having excellent performance can be prepared, so that the electrode sheets have excellent active material adhesion, thereby prolonging the cycle life of batteries.

Description

Coating device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number CN202322360587.4, entitled “Coating Device,” filed with the Patent Office of China on August 31, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of lithium battery manufacturing, and in particular to a coating device. Background Art

[0004] The quality of lithium-ion batteries is crucial to the quality and safety of new energy vehicles. In the production of solid-state lithium-ion batteries, pole piece coating is an essential step, and extrusion coating is currently one of the most commonly used methods for pole piece coating. With the increasing demand for battery cell performance and the need to reduce costs, the development of composite multi-layer coating in solid-state battery preparation has become a new coating trend. Currently, composite coating is mainly achieved through carbon coating of the current collector foil, combined with a double-layer extrusion coating die head to achieve simultaneous coating of the upper and lower slurry layers.

[0005] In the current lithium battery production process, in order to improve the adhesion and electrochemical performance of the electrode, a bottom carbon-coated current collector foil material is usually used as the raw material, and then coated. However, the purchase of carbon-coated foil leads to high raw material production costs and unstable supply cycles. In addition, in terms of production equipment, the existing multi-layer coating of the current collector primer and main slurry is completed through two processes: gravure coating and extrusion coating. The commonly used extrusion coating method does not have the function of extrusion-type integrated coating after primer coating. In addition, gravure coating and extrusion coating are produced in two processes, which have disadvantages in terms of equipment investment cost, plant planning area and production efficiency.

[0006] Application Contents

[0007] In view of this, the present application proposes a coating device to remove oil stains on the surface of the foil, improve the dyne value of the foil surface, and also facilitate the preparation of electrodes with excellent performance.

[0008] In the first aspect, the present application provides a coating device, comprising a corona unit and a coating unit arranged in sequence along the foil conveying direction; the corona unit has a discharge part arranged toward the surface of the foil, and the discharge part is used to perform corona treatment on the surface of the foil; the coating unit has a coating die head, and the coating die head is used to coat the slurry on the surface of the foil after corona treatment.

[0009] Beneficial Effects: The corona treatment unit, located upstream of the coating unit, allows the foil surface to be corona treated before coating. This removes oil stains from the foil surface and increases its dyne value, or tension coefficient. This also allows for the production of high-performance electrodes with excellent active material adhesion, thereby extending the battery's cycle life. This also reduces procurement costs by eliminating the need for carbon-coated foils, resulting in excellent performance.

[0010] In an optional embodiment, the corona unit includes a box body having a foil inlet and a foil outlet; the discharge part is arranged in the box body, and the discharge part includes a first discharge part for corona treatment of the A surface of the foil, and a second discharge part for corona treatment of the B surface of the foil.

[0011] Beneficial effect: The first discharge part and the second discharge part can respectively perform corona treatment on the A side and the B side of the foil, which is beneficial to subsequently improve the coating quality of the A side and the B side of the foil.

[0012] In an optional embodiment, a plurality of conveying rollers for the foil to be wound around are provided in the box; the first discharge portion and the second discharge portion are respectively arranged corresponding to the foil on different conveying rollers, and the first discharge portion and the second discharge portion both have an arc surface profile that matches the outer peripheral surface of the corresponding conveying roller.

[0013] Beneficial effects: Both the first discharge portion and the second discharge portion have arcuate profiles, which can better match the foil wound around the outer circumference of the conveying roller, facilitate corona treatment of the foil, and also facilitate the arrangement of the first discharge portion and the second discharge portion.

[0014] In an optional embodiment, the distance h between each of the arc surface contours and the corresponding outer peripheral surface of the conveying roller satisfies: 5mm≤h≤10mm.

[0015] Beneficial effect: Setting the distance between each arc surface profile and the corresponding outer peripheral surface of the conveying roller is beneficial to ensuring the corona treatment effect of the foil.

[0016] In an optional embodiment, the box body is provided with an air filling port for filling inert gas, and an exhaust port for discharging impurities generated during the corona treatment process, and the exhaust port is connected to a negative pressure fan.

[0017] Beneficial effects: The inlet for inert gas is provided to isolate oxygen from the foil surface during the corona treatment process. The outlet is provided to facilitate the discharge of impurities during the corona treatment process.

[0018] In an optional embodiment, a foil unwinding unit is provided upstream of the corona unit, and the unwinding unit is used to unwind the foil to be coated.

[0019] Beneficial effect: The foil can be unwound through the provided unwinding unit.

[0020] In an optional embodiment, a heating unit and a winding unit are sequentially provided downstream of the coating unit, the heating unit is used to heat the foil coated with the slurry, and the winding unit is used to wind the heated foil.

[0021] Beneficial Effects: The heating unit is used to heat the foil coated with slurry, and the winding unit is used to wind the heated foil. The arrangement of the unwinding unit, heating unit, and winding unit is beneficial to the coating efficiency of the foil.

[0022] In an optional embodiment, the coating die includes an A-side coating die for coating the A-side of the foil with slurry, and a B-side coating die for coating the B-side of the foil with slurry.

[0023] Beneficial effects: The A-side coating die head and the B-side coating die head can coat the slurry on the A-side and B-side of the foil respectively.

[0024] In an optional embodiment, the A-side coating die and / or the B-side coating die has a plurality of coating lips.

[0025] Beneficial effect: The multiple coating lips provided on the A-side coating die head and the B-side coating die head can perform multi-layer coating on the foil surface.

[0026] In an optional embodiment, the A-side coating die head and / or the B-side coating die head are multiple and arranged at intervals.

[0027] Beneficial effect: The coating die heads arranged at intervals can increase the coating coverage area, thereby improving the coating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] FIG1 is a schematic structural diagram of a coating device according to an embodiment of the present application;

[0030] FIG2 is a schematic structural diagram of a corona unit and a coating unit according to an embodiment of the present application;

[0031] FIG3 is an enlarged structural diagram of the corona unit according to an embodiment of the present application;

[0032] FIG4 is a schematic structural diagram of a coating unit according to an embodiment of the present application.

[0033] Description of reference numerals:

[0034] 1. Unwinding unit; 2. Corona and coating unit; 3. Heating unit; 4. Rewinding unit; 21. Box; 22. First discharge section; 23. Second discharge section; 24. B-side coating die; 25. A-side coating die; 211. Inflating port; 212. Discharge port; 220. Discharge electrode; 222. Insulating bracket; 24a. First coating die; 24b. Second coating die; 10. Foil; 20. Negative pressure blower; 30. Ozone processor. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0036] This embodiment relates to a coating device, which can remove oil stains on the surface of the foil 10, improve the dyne value of the surface of the foil 10, and is also conducive to the preparation of electrodes with excellent performance.

[0037] In terms of overall structure, as shown in Figures 1 and 2 , the coating device of this embodiment primarily comprises a corona unit and a coating unit, arranged sequentially along the conveying direction of the foil 10. The corona unit comprises a discharge portion, facing the surface of the foil 10, for performing a corona treatment on the surface of the foil 10. The coating unit comprises a coating die head, which is used to apply a slurry to the surface of the foil 10 after the corona treatment.

[0038] In the above structure, a corona treatment unit located upstream of the coating unit is used to treat the surface of the foil 10 before coating. This removes oil stains from the surface of the foil 10 and increases the dyne value of the surface of the foil 10, thereby increasing the surface tension coefficient of the foil 10. Furthermore, this coating device can produce high-performance electrode sheets with excellent active material adhesion, thereby increasing the cycle life of the battery. It also saves procurement costs by eliminating the need to purchase foil 10 with a carbon-coated bottom layer.

[0039] It should be noted that the corona unit provided in this embodiment can perform corona treatment on only one side of the foil 10, that is, perform corona treatment on side A of the foil 10 or side B of the foil 10, and then apply slurry to the side through the coating die head in the coating unit. Of course, it is also possible to perform corona treatment on both sides of the foil 10, and after the corona treatment, the coating die head in the coating unit is used to coat both sides of the foil 10.

[0040] The following specifically describes in detail a coating device for performing corona treatment on both sides of the foil 10 .

[0041] Continuing to refer to FIG. 1 and FIG. 2 , in the coating device of this embodiment, the corona and coating unit 2 as shown in FIG. 1 includes a corona unit and a coating unit. The corona unit is arranged upstream of the coating unit, and the corona unit includes a box 21 having an inlet for the foil 10 and an outlet for the foil 10, and a cavity is formed inside the box 21. The above-mentioned discharge section is specifically arranged in the box 21, and the discharge section includes a first discharge section 22 for performing corona treatment on the A surface of the foil 10, and a second discharge section 23 for performing corona treatment on the B surface of the foil 10. The arrangement of the first discharge section 22 and the second discharge section 23 can perform corona treatment on the A surface and the B surface of the foil 10 respectively, which is beneficial to subsequently improving the coating quality of the A surface and the B surface of the foil 10.

[0042] As a preferred embodiment, in this embodiment, as shown in Figure 2 , a plurality of conveyor rollers are provided within a housing 21 for winding the foil 10. The first and second discharge sections 22, 23 are positioned corresponding to the foil 10 on different conveyor rollers, and each has a curved profile that matches the outer circumference of the corresponding conveyor roller. This curved profile allows the discharge section to better match the foil 10 wound around the outer circumference of the conveyor roller, facilitating corona treatment of the foil 10 and facilitating the arrangement of the first and second discharge sections 22, 23.

[0043] It can be understood here that, in addition to adopting the above-mentioned structural form and winding around multiple conveying rollers in sequence, the foil 10 also sets the foil 10 inlet and the foil 10 outlet in the same line. At this time, conveying rollers are set at the foil 10 inlet and the foil 10 outlet, and conveying rollers may or may not be set in the box 21. The first discharge section 22 and the second discharge section 23 are respectively set on the opposite sides of the foil 10 to perform corona treatment on the two surfaces of the foil 10. Such an arrangement is also feasible.

[0044] As a preferred embodiment, as shown in FIG3 , the distance h between the arcuate profile of the first discharge portion 22 and the outer circumference of the corresponding conveyor roller is set to 5 mm ≤ h ≤ 10 mm. This arrangement helps ensure the corona treatment effect on the foil 10. In practice, the distance h can be set to 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, for example.

[0045] The principle of corona is to use high frequency and high voltage to perform corona discharge on the surface of the processed material, that is, the foil 10. During the discharge, low-temperature plasma is generated, which causes free radical reactions on the surface of the material to cause the polymer to cross-link. The surface becomes rough and its wettability to polar solvents is increased. These ions enter the surface of the printed material through electric shock and penetration, destroying its molecular structure, and then oxidizing and polarizing the surface molecules to be processed. The ion electric shock erodes the surface, thereby increasing the adhesion ability of the material surface.

[0046] During the corona treatment process, the surface of the foil 10 must be protected from oxidation. Furthermore, the corona treatment process also generates ozone and other impurities. To facilitate the smooth corona treatment of the foil 10, in this embodiment, the housing 21 is provided with an inlet 211 for introducing inert gas and an outlet 212 for discharging impurities generated during the corona treatment. The outlet 212 is connected to a negative pressure blower 20. Furthermore, the end of the negative pressure blower 20, remote from the outlet 212, is connected to an ozone treatment device 30. The ozone treatment device 30 can treat the generated ozone using activated carbon or catalytic reduction methods.

[0047] At this time, during the corona treatment process, the inert gas injected can effectively isolate oxygen from contacting the surface of the foil 10. The negative pressure blower 20 provided at the discharge port 212 can facilitate the timely discharge of impurities during the corona treatment process, thereby improving the corona treatment effect of the foil 10.

[0048] In this embodiment, both the first and second discharge sections 22, 23 utilize a plurality of elongated discharge electrodes 220 arranged in a curved configuration. Furthermore, the first and second discharge sections 22, 23 are also secured to an insulating bracket 222. It should be noted that the circuit connections of the first and second discharge sections 22, 23, as well as any structures not described in the corona unit, can be referenced to the structure of existing corona treaters.

[0049] In this embodiment, an unwinding unit 1 for the foil 10 is provided upstream of the corona unit, and the unwinding unit 1 is used to unwind the foil 10 to be coated. A heating unit 3 and a winding unit 4 are also provided downstream of the coating unit in sequence, wherein the heating unit 3 is used to heat the foil 10 coated with the slurry, and the winding unit 4 is used to wind the heated foil 10.

[0050] It should be noted that the specific structures of the unwinding unit 1 and the rewinding unit 4 of this embodiment can refer to the structures in the prior art. In order to ensure smooth unwinding and rewinding of the foil 10, the unwinding unit 1 and the rewinding unit 4 can also be equipped with a deviation correction mechanism, a static elimination mechanism, and a tension control mechanism in the prior art. In addition, it should be noted that the specific structure of the heating unit 3 of this embodiment also refers to the structure in the prior art.

[0051] In this embodiment, the coating die includes an A-side coating die 25 for coating the slurry on the A side of the foil 10, and a B-side coating die 24 for coating the slurry on the B side of the foil 10. The A-side coating die 25 and the B-side coating die 24 can respectively coat the A side and the B side of the foil 10 with the slurry.

[0052] As shown in FIG2 , in this embodiment, both the A-side coating die 25 and the B-side coating die 24 have multiple coating lips. This allows for multi-layer coating on both surfaces of the foil 10. It should be understood that, in addition to the above arrangement, only the A-side coating die 25 or only the B-side coating die 24 may also have multiple coating lips.

[0053] As another arrangement, as shown in FIG4 , the A-side coating die 25 and the B-side coating die 24 are both arranged in a plurality at intervals, that is, they include a first coating die 24 a and a second coating die 24 b arranged at intervals along the conveying direction of the foil 10. The first coating die 24 a has one coating lip, and the second coating die 24 b has two coating lips, so that three layers of slurry can be coated on both surfaces of the foil 10.

[0054] It should be noted that it is also possible to provide only the A-side coating die heads 25 with a plurality of spaced-apart coating heads, or only the B-side coating die heads 24 with a plurality of spaced-apart coating heads. The number of coating lips on the coating die heads can be adjusted accordingly based on actual needs. Furthermore, it should be noted that the specific structures of the A-side coating die heads 25 and the B-side coating die heads 24 can refer to structures in the prior art.

[0055] In addition, during the coating process of the foil 10, in order to ensure the quality of the coating, thickness measuring mechanisms are set upstream of the corona and downstream of the coating to measure the thickness of the foil 10 before and after coating. This is conducive to ensuring the quality of the coating material and the uniformity of the surface density.

[0056] When the coating device of this embodiment is used, the unwinding unit 1 first unwinds the foil 10. The conveyed foil 10 passes through the first discharge section 22 and the second discharge section 23, and corona treatment is performed on the A side and B side of the foil 10. The foil 10 then passes through the B side coating die 24 and the A side coating die 25, and multi-layer coating is performed on the B side and A side of the foil 10. The foil 10 is then dried by the heating device and rewound after drying.

[0057] The coating device of this embodiment, through the corona unit disposed upstream of the coating unit, can form and coat a high-performance electrode sheet, which has excellent active material adhesion, thereby increasing the cycle life of the battery. It also saves procurement costs by eliminating the need to purchase a bottom carbon-coated foil 10, and also helps improve the adhesion of the bottom active material of the multi-layer coating.

[0058] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims. Industrial Applicability

[0059] The corona treatment unit, located upstream of the coating unit, can be used to treat the foil surface with a corona treatment before coating. This removes oil stains from the foil surface and increases the dyne value (or tension coefficient) of the foil surface. This allows for the formation and coating of high-performance pole pieces, which possess excellent adhesion to the active material and extend the battery's cycle life. This also saves procurement costs by eliminating the need for a carbon-coated bottom foil and helps improve the adhesion of the active material in the bottom layer of multi-layer coatings.

Claims

1. A coating device, characterized in that: It includes a corona unit and a coating unit which are sequentially arranged along the foil conveying direction; The corona unit has a discharge portion arranged toward the surface of the foil material, and the discharge portion is used to perform corona treatment on the surface of the foil material; The coating unit has a coating die head, and the coating die head is used to coat the slurry on the surface of the foil after the corona treatment.

2. The coating device according to claim 1, characterized in that: The corona unit comprises a box having a foil inlet and a foil outlet; The discharge part is arranged in the box, and includes a first discharge part for performing corona treatment on the A surface of the foil material, and a second discharge part for performing corona treatment on the B surface of the foil material.

3. The coating device according to claim 2, characterized in that: The box body is provided with a plurality of conveying rollers for the foil material to be wound around; The first discharging portion and the second discharging portion are respectively arranged corresponding to the foil materials on different conveying rollers, and the first discharging portion and the second discharging portion both have an arc surface profile matching the outer peripheral surface of the corresponding conveying roller.

4. The coating device according to claim 3, characterized in that: The distance h between each of the arc surface contours and the corresponding outer peripheral surface of the conveying roller satisfies: 5mm≤h≤10mm.

5. The coating device according to claim 2, characterized in that: The box body is provided with an air filling port for filling inert gas, and an exhaust port for exhausting impurities generated during the corona treatment process, and the exhaust port is connected to a negative pressure fan.

6. The coating device according to claim 1, characterized in that: A foil unwinding unit is disposed upstream of the corona unit, and the unwinding unit is used to unwind the foil to be coated.

7. The coating device according to claim 1, characterized in that: A heating unit and a winding unit are sequentially arranged downstream of the coating unit. The heating unit is used to heat the foil coated with the slurry, and the winding unit is used to wind up the heated foil.

8. The coating device according to any one of claims 1 to 7, characterized in that: The coating die head includes an A-side coating die head for coating the A-side of the foil with slurry, and a B-side coating die head for coating the B-side of the foil with slurry.

9. The coating device according to claim 8, characterized in that: The A-side coating die and / or the B-side coating die has a plurality of coating lips.

10. The coating device according to claim 8, characterized in that: The A-side coating die head and / or the B-side coating die head are multiple and spaced apart.

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