Coating system

Abstract

The utility model relates to the technical field of lithium battery production, in particular to a coating system, which is characterized in that an a-surface initial section and a b-surface initial section are arranged on the upper circumferential surface of a carrier roller group, an active substance is arranged upwards and is uniformly supported by the carrier roller group; the active substance of the pole piece is uniformly deposited along with the dried active substance when the active substance is in a slurry state and has relatively high fluidity after being coated, and the active substance is kept stable in the process of converting the dried active substance from the slurry state with relatively high fluidity into a relatively dense semi-slurry state which is not easy to deform; according to the drying device, the surface-a drying section and the surface-b drying section are arranged in the drying cavity, so that the active material slurry is prevented from deforming, uneven in thickness and even slipping off from the surface of the electrode when being dried by hot air, and the electrode plate is provided with a drying path for returning movement in the drying cavity through the returning arrangement of the surface-a drying section and the surface-b drying section; the pole piece has a longer drying path in the drying oven of unit length, so that the length of the drying oven can be reduced, and the occupied area of the drying oven is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery production technical field, specifically, relate to a coating system. BACKGROUND

[0002] The coating process in the existing battery production process is a crucial process, in the coating process, first of all, the coating machine is coated on the surface of the pole piece, then the wet pole piece is heated by the oven, the coating material on the pole piece is dried, and the dry pole piece is formed. Limited by the strength of the pole piece, the running speed of the pole piece cannot be too fast in the drying process, and enough drying time is required to ensure the drying effect of the coating material, therefore, the oven usually has a long length in the direction of the pole piece running to meet the drying time requirement of the pole piece, the oven has a large floor area, resulting in low utilization rate of the factory building.

[0003] In order to solve the problem of large floor area of the oven in the prior art, a kind of oven is provided in the related art, two groups of parallelly arranged air nozzles are arranged in the oven, the pole piece enters the oven first and is dried by the first group of air nozzles, and after reversing, it passes through the second group of air nozzles, the oven has two parallel drying paths, under the condition that the running speed of the pole piece is the same, the length of the oven can be reduced by half compared with the oven in the prior art, however, this arrangement makes the pole piece move in a U-shaped manner, and there is a situation that the pole piece is upside down in one of the drying paths, when the pole piece is upside down during drying, the slurry of active material is prone to unstable deposition due to gravity, and when it is blown by hot air during drying, the slurry is unevenly distributed, and even the active material slips from the electrode surface, thereby affecting the performance and cycle life of the battery.

[0004] Therefore, there is an urgent need to invent a coating system. UTILITY MODEL CONTENT

[0005] The utility model aims at: in view of the deficiencies of prior art, provide a kind of coating system, while reducing the length of oven, guarantee the stability of pole piece during drying, reduce the influence of hot air blowing on pole piece during drying.

[0006] To solve the above technical problems, the following technical scheme is adopted in the present application:

[0007] A coating system is provided, which includes an oven, the oven includes two drying cavities arranged along the height direction of the oven, the two drying cavities are respectively arranged as a-face drying area and b-face drying area, the pole piece is conveyed to the a-face drying area for hot air drying after coating a-face, and is conveyed to the b-face drying area for hot air drying after coating b-face, at least one reversing roller and at least one set of idler rollers are arranged in the a-face drying area and the b-face drying area;

[0008] In the a-plane drying area, the plurality of supporting rollers and the reversing roller are arranged along an a-plane drying path, the a-plane drying path is divided into an a-plane initial section and an a-plane drying section, the a-plane initial section starts from the entering of the pole piece into the a-plane drying area, is arranged along the upper circumferential surface of the plurality of supporting rollers until the reversing roller, and ends at the reversing roller, and the a-plane drying section starts from the reversing roller, is arranged along the lower circumferential surface of the plurality of supporting rollers after being folded back by the reversing roller, and ends at the leaving of the pole piece from the a-plane drying area.

[0009] In the b-plane drying area, the plurality of supporting rollers and the reversing roller are arranged along a b-plane drying path, the b-plane drying path is divided into a b-plane initial section and a b-plane drying section, the b-plane initial section starts from the entering of the pole piece into the b-plane drying area, is arranged along the upper circumferential surface of the plurality of supporting rollers until the reversing roller, and ends at the reversing roller, and the a-plane drying section starts from the reversing roller, is arranged along the lower circumferential surface of the plurality of supporting rollers after being folded back by the reversing roller, and ends at the leaving of the pole piece from the b-plane drying area.

[0010] A first air nozzle assembly and a second air nozzle assembly are arranged along the a-plane initial section and the a-plane initial section respectively, and the first air nozzle assembly and the second air nozzle assembly are arranged above the plurality of supporting rollers and are respectively arranged towards the a-plane and the b-plane of the pole piece.

[0011] Specifically, a first reversing roller and a second reversing roller are arranged at the two ends of the length direction of the oven respectively, and the pole piece enters the b-plane drying area after sequentially passing through the first reversing roller and the second reversing roller after leaving the a-plane drying area, and the a-plane and the b-plane of the pole piece are opposite before and after passing through the first reversing roller and the second reversing roller.

[0012] Specifically, a third air nozzle assembly and a fourth air nozzle assembly are arranged along the a-plane drying section and the b-plane drying section respectively, and the third air nozzle assembly and the fourth air nozzle assembly are arranged below the plurality of supporting rollers and are respectively arranged towards the a-plane and the b-plane of the pole piece, and the planes where the first air nozzle assembly, the second air nozzle assembly, the third air nozzle assembly, the fourth air nozzle assembly and the plurality of supporting rollers are arranged are all parallel to each other.

[0013] Specifically, one of the plurality of supporting rollers is arranged in the a-plane drying area, and the a-plane initial section and the a-plane drying section are arranged on the upper circumferential surface and the lower circumferential surface of the plurality of supporting rollers respectively, and one of the plurality of supporting rollers is arranged in the b-plane drying area, and the b-plane initial section and the b-plane drying section are arranged on the upper circumferential surface and the lower circumferential surface of the plurality of supporting rollers respectively.

[0014] Specifically, the plurality of supporting rollers in the a-plane drying area are arranged between the first air nozzle assembly and the third air nozzle assembly, and the plurality of supporting rollers in the b-plane drying area are arranged between the second air nozzle assembly and the fourth air nozzle assembly.

[0015] Specifically, the oven is respectively provided with an a-surface coating die head and a b-surface coating die head at two ends, and a coating roller is arranged close to the a-surface coating die head and the b-surface coating die head.

[0016] Specifically, the device further comprises a guide roller arranged between the coating roller and the group of supporting rollers, for guiding the flow of the pole piece from the coating roller to the group of supporting rollers, wherein the guide roller abuts against a surface away from the coated surface of the pole piece.

[0017] Specifically, a fifth group of supporting rollers is arranged between the first reversing roller and the second reversing roller.

[0018] Specifically, the oven is respectively provided with a winding device and an unwinding device at two ends in the length direction.

[0019] Specifically, the winding device and the unwinding device are arranged on the ground.

[0020] The device has the advantages that: the a-surface initial section and the b-surface initial section are arranged on the upper circumferential surface of the group of supporting rollers, the active substance is arranged upward and supported by the group of supporting rollers, the active substance of the pole piece has high flowability when it is in the slurry state after being coated, and the active substance is uniformly deposited after being dried, the active substance remains stable during the process of being dried from the slurry state with high flowability to the semi-slurry state with high density and low deformation, the active substance slurry does not deform, is not uniform in thickness, and does not slide off the electrode surface when being dried by hot air, the a-surface drying section and the b-surface drying section are arranged in a folded-back manner, the pole piece has a folded-back drying path in the drying cavity, the pole piece has a longer drying path in the oven per unit length, the length of the oven can be reduced, and the floor area occupied by the oven can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the present application and constitute a part of this application, illustrate embodiments of the present application and together with the general description of the application given above and the detailed description of the application given below, serve to explain the present application. In the drawings:

[0022] Figure 1 The accompanying drawings, which are included to provide a further understanding of the present application and constitute a part of this application, illustrate embodiments of the present application and together with the general description of the application given above and the detailed description of the application given below, serve to explain the present application. In the drawings:

[0023] Wherein: 1-oven; 11-oven cavity; 12-a surface drying area; 121-a group of godets; 122-a reversing roller; 123-a first air nozzle assembly; 124-a second air nozzle assembly; 125-a third air nozzle assembly; 126-a fourth air nozzle assembly; 13-b surface drying area; 14-a surface drying path; 141-a initial section of a surface; 142-a drying section of a surface; 15-b surface drying path; 151-b initial section of a surface; 152-b drying section of a surface; 16-first direction changing roller; 17-second direction changing roller; 18-fifth group of godets; 2-a surface coating die head; 3-b surface coating die head; 4-coating roller; 5-winding device; 6-unwinding device; 7-guide roller. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. Unless otherwise defined, all the technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application.

[0025] In the description of the present application, unless otherwise explicitly defined and limited, the terms "mounting", "connecting", "connecting", "fixing" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0026] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the claims, and any person skilled in the art can make several possible changes and modifications without departing from the concept of the present application, therefore the protection scope of the present application should be limited by the scope defined by the claims of the present application.

[0027] The drying process of the active material slurry is that solvent evaporation promotes the redistribution of the active material, and as the solvent evaporates, the slurry stage becomes a semi-slurry stage, and then further removes the solvent to form the condensed layer of the coating, and finally forms a compact solid thin film coating. In the slurry stage, the active material with high fluidity of solid particles uniformly suspended in the liquid medium is easy to deform, and in the semi-slurry stage, as the solvent evaporates, the liquid medium is insufficient to suspend the solid particles, but there is still a lot of liquid medium in the gap between the solid particles without drying. In this stage, the fluidity of the active material decreases and the active material is not easy to deform.

[0028] In the prior art, the pole piece is moved in the oven to fold back, so that the pole piece has a longer moving drying path in the oven of the same size, thereby reducing the volume of the oven, and due to the reduced volume of the oven, less heat is lost, thereby reducing energy loss. However, the setting of the folding back part causes the pole piece to have a part that needs to be dried with the active material facing down, and the slurry of the active material is easy to cause unstable deposition due to the influence of gravity. When affected by the hot air blowing, the slurry of the active material is easy to deform, resulting in uneven thickness of the active material, and the active material is easy to fall off from the pole piece.

[0029] The present application changes the drying process of the active material slurry from the slurry stage to the semi-slurry stage of the pole piece to a stable state by setting the initial section with the active material facing up, so as to ensure that the active material will not deform greatly during the process of solvent evaporation promoting the redistribution of the active material. And because the active material slurry changes from the slurry stage to the semi-slurry stage, the pole piece passing through the initial section has good stability and is not easy to deform, so as to ensure that the pole piece is not easy to deform due to the influence of gravity in the subsequent drying path.

[0030] As Figure 1As shown, the present application provides a coating system, which comprises an oven 1, the oven 1 comprises two oven cavities 11 arranged along the height direction of the oven 1, the two oven cavities 11 are respectively arranged as an a-surface drying area 12 and a b-surface drying area 13, the pole piece is conveyed into the a-surface drying area 12 for hot air drying after coating the a-surface, and is conveyed into the b-surface drying area 13 for hot air drying after coating the b-surface, at least one reversing roller 122 and at least one supporting roller group 121 are arranged in the a-surface drying area 12 and the b-surface drying area 13; in the a-surface drying area 12, the supporting roller group 121 and the reversing roller 122 are arranged along an a-surface drying path 14, the a-surface drying path 14 is divided into an a-surface initial section 141 and an a-surface drying section 142, the a-surface initial section 141 starts from the entrance of the pole piece into the a-surface drying area 12, is arranged along the upper circumferential surface of the supporting roller group 121 until the reversing roller 122, the upper circumferential surface is the upper half of the curved surface formed by the supporting roller in the circumferential direction, and the a-surface drying section 142 is arranged along the lower circumferential surface of the supporting roller group 121 after the reversing roller 122 and is folded back, until the exit of the a-surface drying area 12, the lower circumferential surface is the lower half of the curved surface formed by the supporting roller in the circumferential direction; in the b-surface drying area 13, the supporting roller group 121 and the reversing roller 122 are arranged along a b-surface drying path 15, the b-surface drying path 15 is divided into a b-surface initial section 151 and a b-surface drying section 152, the b-surface initial section 151 starts from the entrance of the pole piece into the b-surface drying area 13, is arranged along the upper circumferential surface of the supporting roller group 121 until the reversing roller 122, and the b-surface drying section 152 is arranged along the lower circumferential surface of the supporting roller group 121 after the reversing roller 122 and is folded back, until the exit of the b-surface drying area 13; a first air nozzle assembly 123 and a second air nozzle assembly 124 are arranged along the a-surface initial section 141 and the b-surface initial section 151 respectively, the first air nozzle assembly 123 and the second air nozzle assembly 124 are arranged above the supporting roller group 121 and are distributed towards the a-surface of the pole piece and the b-surface of the pole piece.

[0031] For example, when the pole piece enters the a-plane drying area 12, it first moves along the a-plane initial section 141. When the pole piece is in the a-plane initial section 141, the active material on the a-plane is arranged upward and faces the first air nozzle assembly 123. The hot air blown by the first air nozzle assembly 123 dries the pole piece. Because the active material on the a-plane is arranged upward when the pole piece is in the a-plane initial section 141, the pole piece is uniformly supported by the supporting roller group 121, and the gravity helps the active material to be uniformly deposited. As the pole piece continuously moves in the a-plane initial section 141, it is continuously dried. As the solvent evaporates, the active material changes from the slurry stage to the semi-slurry stage. After passing through the a-plane initial section 141, the flowability of the pole piece decreases, and the pole piece is not easy to deform and has good stability. When the pole piece passes through the a-plane drying section 142, it first flows to the reversing roller 122. Under the guidance of the reversing roller 122, the pole piece turns and flows to the lower circumferential surface of the supporting roller group 121 to realize the turning back. The pole piece is continuously dried until it leaves the a-plane drying area 12. The drying process of the b-plane of the pole piece is the same as that of the a-plane, and details are not described here.

[0032] The coating system of the present application keeps the existing technology to reduce the volume of the oven 1 by setting the drying path to turn back, saves space, ensures the stability of the pole piece during drying by setting the a-plane initial section 141 and the b-plane initial section 151, and reduces the influence of the hot air blowing on the pole piece during drying.

[0033] Preferably, the first reversing roller 16 and the second reversing roller 17 are respectively arranged at the two ends of the length direction of the oven 1. After the pole piece leaves the a-plane drying area 12, it passes through the first reversing roller 16 and the second reversing roller 17 in sequence and enters the b-plane drying area 13. When the pole piece is dried in the a-plane drying area 12, the orientation of the pole piece changes. In order to keep the active material on the b-plane of the pole piece arranged upward when the pole piece flows into the b-plane drying area 13, the pole piece needs to be turned back twice by the first reversing roller 16 and the second reversing roller 17. The orientations of the a-plane and the b-plane of the pole piece are opposite before and after the pole piece passes through the first reversing roller 16 and the second reversing roller 17.

[0034] In some embodiments, the fifth supporting roller group 18121 is arranged between the first reversing roller 16 and the second reversing roller 17, which is helpful to keep the flatness and stability of the pole piece. The supporting roller helps to support and guide the pole piece.

[0035] Preferably, the third air nozzle assembly 125 and the fourth air nozzle assembly 126 are respectively arranged along the a-plane drying section 142 and the b-plane drying section 152. The third air nozzle assembly 125 and the fourth air nozzle assembly 126 are both arranged below the supporting roller group 121 and are respectively arranged towards the a-plane of the pole piece and the b-plane of the pole piece. The planes where the first air nozzle assembly 123, the second air nozzle assembly 124, the third air nozzle assembly 125, the fourth air nozzle assembly 126, and the supporting roller group 121 are arranged are all parallel to each other. The parallel arrangement is helpful to save the space in the oven 1 and reduce the space occupied by the oven 1.

[0036] Preferably, a face drying area 12 is provided with a group of supporting rollers 121, and the a face initial section 141 and the a face drying section 142 are arranged on the upper and lower circumferential surfaces of the group of supporting rollers 121 respectively, the b face drying area 13 is provided with a group of supporting rollers 121, and the b face initial section 151 and the b face drying section 152 are arranged on the upper and lower circumferential surfaces of the group of supporting rollers 121 respectively, the group of supporting rollers 121 of the a face drying area 12 is arranged between the first air nozzle assembly 123 and the third air nozzle assembly 125, the group of supporting rollers 121 of the b face drying area 13 is arranged between the second air nozzle assembly 124 and the fourth air nozzle assembly 126, and the a face drying area 12 is arranged above the b face drying area 13, the first air nozzle assembly 123 dries the pole piece when the pole piece passes through the upper circumferential surface of the group of supporting rollers 121, and the third air nozzle assembly 125 dries the pole piece after the pole piece moves to the lower circumferential surface of the group of supporting rollers 121 after passing through the reversing roller 122, and this arrangement of the group of supporting rollers 121 is conducive to saving space.

[0037] Specifically, the oven 1 is provided with an a face coating die head 2 and a b face coating die head 3 at two ends respectively, and a coating roller 4 is arranged close to the a face coating die head 2 and the b face coating die head 3, and the arrangement of the coating device at the two ends of the oven 1 is conducive to the arrangement of the device.

[0038] Preferably, a guide roller 7 is arranged between the coating roller 4 and the group of supporting rollers 121, and is used to guide the pole piece to flow from the coating roller 4 to the group of supporting rollers 121, wherein the guide roller 7 is in abutment with one side away from the coating surface of the pole piece, so that the guide roller 7 provides support for the pole piece below the pole piece, and the active substance coated at the coating roller 4 does not contact the guide roller 7 to prevent the structure of the active substance from being damaged.

[0039] Preferably, the oven 1 is provided with a winding device 5 and an unwinding device 6 at the two ends in the length direction respectively, and the unwinding device 6 and the winding device 5 are arranged at the two ends in the length direction of the oven 1, which is conducive to the layout of the workshop.

[0040] Specifically, the winding device 5 and the unwinding device 6 are arranged on the ground, and the arrangement of the device on the ground can provide a more stable foundation, reduce the transmission of vibration, and avoid the problem of active substance surface density fluctuation caused by steel structure vibration.

[0041] The above description shows and describes several preferred embodiments of the present application, but as before, it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the present application concept, by the above teaching or related technical or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the appended claims of the present application.

Claims

1. A coating system characterized by: The oven (1) comprises two baking cavities (11) arranged along the height direction of the oven (1), the two baking cavities (11) are respectively arranged as an a-surface drying area (12) and a b-surface drying area (13), the pole piece is conveyed into the a-surface drying area (12) for hot air drying after coating the a-surface, and is conveyed into the b-surface drying area (13) for hot air drying after coating the b-surface, at least one reversing roller (122) and at least one supporting roller group (121) are arranged in the a-surface drying area (12) and the b-surface drying area (13). In the a-surface drying area (12), the supporting roller group (121) and the reversing roller (122) are arranged along an a-surface drying path (14), the a-surface drying path (14) is divided into an a-surface initial section (141) and an a-surface drying section (142), the a-surface initial section (141) starts from the pole piece entering the a-surface drying area (12), is arranged along the upper circumferential surface of the supporting roller group (121) and ends at the reversing roller (122), and the a-surface drying section (142) starts from the reversing roller (122), is arranged along the lower circumferential surface of the supporting roller group (121) after being folded back by the reversing roller (122) and ends when leaving the a-surface drying area (12). In the b-surface drying area (13), the supporting roller group (121) and the reversing roller (122) are arranged along a b-surface drying path (15), the b-surface drying path (15) is divided into a b-surface initial section (151) and a b-surface drying section (152), the b-surface initial section (151) starts from the pole piece entering the b-surface drying area (13), is arranged along the upper circumferential surface of the supporting roller group (121) and ends at the reversing roller (122), and the a-surface drying section (142) starts from the reversing roller (122), is arranged along the lower circumferential surface of the supporting roller group (121) after being folded back by the reversing roller (122) and ends when leaving the b-surface drying area (13). A first air nozzle assembly (123) and a second air nozzle assembly (124) are arranged along the a-surface initial section (141) and the b-surface initial section (151) respectively, the first air nozzle assembly (123) and the second air nozzle assembly (124) are arranged above the supporting roller group (121) and are distributed towards the a-surface of the pole piece and the b-surface of the pole piece.

2. The coating system of claim 1, wherein: A first reversing roller (16) and a second reversing roller (17) are arranged at the two ends of the length direction of the oven (1) respectively, the pole piece enters the b-surface drying area (13) after passing through the first reversing roller (16) and the second reversing roller (17) in sequence after leaving the a-surface drying area (12), and the a-surface and the b-surface of the pole piece are opposite before and after passing through the first reversing roller (16) and the second reversing roller (17).

3. The coating system of claim 1, wherein: A third air nozzle assembly (125) and a fourth air nozzle assembly (126) are arranged along the a-side drying section (142) and the b-side drying section (152) respectively, and the third air nozzle assembly (125) and the fourth air nozzle assembly (126) are arranged below the roller group (121) and face the a-side and the b-side respectively, and the planes of the first air nozzle assembly (123), the second air nozzle assembly (124), the third air nozzle assembly (125), the fourth air nozzle assembly (126) and the roller group (121) are parallel to each other.

4. The coating system of claim 3, wherein: The a-side drying area (12) is provided with a roller group (121), and the a-side initial section (141) and the a-side drying section (142) are arranged on the upper and lower circumferential surfaces of the roller group (121) respectively, and the b-side drying area (13) is provided with a roller group (121), and the b-side initial section (151) and the b-side drying section (152) are arranged on the upper and lower circumferential surfaces of the roller group (121) respectively.

5. The coating system of claim 4, wherein: The roller group (121) of the a-side drying area (12) is arranged between the first air nozzle assembly (123) and the third air nozzle assembly (125), and the roller group (121) of the b-side drying area (13) is arranged between the second air nozzle assembly (124) and the fourth air nozzle assembly (126).

6. The coating system of claim 1, wherein: The oven (1) is provided with an a-side coating die (2) and a b-side coating die (3) at both ends respectively, and a coating roller (4) is arranged close to the a-side coating die (2) and the b-side coating die (3).

7. The coating system of claim 6, wherein: A guide roller (7) is further arranged between the coating roller (4) and the roller group (121) to guide the movement of the pole piece from the coating roller (4) to the roller group (121), and the guide roller (7) abuts against a side away from the coating surface of the pole piece.

8. The coating system of claim 2, wherein: A fifth roller group (18) is arranged between the first deflection roller (16) and the second deflection roller (17).

9. The coating system of claim 1, wherein: The oven (1) is provided with a winding device (5) and an unwinding device (6) at both ends in the length direction respectively.

10. The coating system of claim 9, wherein: The winding device (5) and the unwinding device (6) are arranged on the ground.

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