Coating device

Abstract

According to the coating device, the backflow opening is formed in the coating die head and connected with the backflow valve of the backflow assembly, and part of coating slurry can flow back through the backflow valve to relieve the pressure of the containing cavity of the coating die head at the moment that the slurry flows into the containing cavity from the feeding opening and is sprayed from the discharging opening for coating. And the backflow amount and the backflow speed can be adjusted through the arrangement of the backflow valve structure and the driving cooperation of the driving part, so that the coating head thickness is actively adjusted, and the adjusting accuracy is improved. Besides, the valve element of the return valve reciprocates, resistance to slurry return is different when the valve element moves back and forth, pressure fluctuation on the coating die head is large, the driving piece drives the valve element to move in one direction, and then a return channel can be connected or disconnected, namely opening and closing of the whole return valve can be completed through one-way and one-way movement of the valve element; and unstable slurry flowing and unstable pressure of the coating die head containing cavity caused by reciprocating motion of the valve element are avoided, and the coating stability and accuracy are improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing equipment, and more specifically, to a coating device. Background Art

[0002] At the moment of starting to coat the battery electrode plate by the coating device, the pressure in the cavity of the coating die head suddenly increases, and the slurry is ejected from the discharge port of the coating die head under the influence of the pressure, which usually causes the head position of the electrode plate to be too thick, also known as "thick head", thus affecting the quality of the battery electrode plate. In the related art, passive pressure relief devices such as pressure regulating pistons are used to relieve the influence of the pressure in the coating die head on the "thick head" of the coating. The passive pressure relief device cannot actively adjust the "thick head" of the coating, is not conducive to controlling the stability of the coating, and has a low accuracy. Summary of the Utility Model

[0003] The purpose of the embodiment of the present application is to provide a coating device, which can improve the coating stability and accuracy and solve the technical problem of the thick head at the head of the battery electrode plate.

[0004] The embodiment of the present application provides a coating device for coating a battery electrode plate, including:

[0005] A coating die head, which has a receiving cavity inside, and the coating die head is provided with an independent return port, a feeding port and a discharge port, and the return port, the feeding port and the discharge port are all communicated with the receiving cavity; and

[0006] A return assembly, the return assembly includes a return valve and a driving member, the return valve includes a valve body and a valve core, the valve body is connected to the coating die head, the valve body has a return channel communicated with the return port, the valve core is located in the return channel, the driving member is connected to the valve core, and the driving member is used to drive the valve core to move unidirectionally so that the return channel is communicated or disconnected.

[0007] In one embodiment, the valve body includes:

[0008] A valve body proper, the return channel is located in the valve body proper; and

[0009] A first baffle and a second baffle, which are arranged at intervals in the return channel and are respectively connected to the inner wall of the valve body proper, the extending direction of the first baffle and the extending direction of the second baffle both intersect with the extending direction of the return channel, the valve core is located between the first baffle and the second baffle, and openings are provided on both the first baffle and the second baffle;

[0010] The driving member drives the valve core to move unidirectionally so that the return valve is opened or closed;

[0011] In the open state, the valve core is spaced from both the first baffle and the second baffle, and the return channel is communicated;

[0012] In the closed state, the valve core abuts against one of the first baffle and the second baffle and is clamped in the corresponding opening, the valve core is spaced from the other of the first baffle and the second baffle, and the return channel is disconnected.

[0013] In one embodiment, the valve core includes a first sub - part and a second sub - part. Both the first sub - part and the second sub - part are connected to the driving member. The first sub - part is located between the first baffle and the second baffle, and the second sub - part is located on the side of the first sub - part away from the first baffle;

[0014] In the open state, the first sub - part is spaced from the first baffle, the second sub - part is spaced from the second baffle, and the return channel is communicated;

[0015] In the closed state, the first sub - part abuts against the first baffle and the second sub - part is spaced from the second baffle, or the first sub - part is spaced from the first baffle and the second sub - part abuts against the second baffle.

[0016] In one embodiment, the valve body includes a valve body, a first baffle and a second baffle. The return channel is located inside the valve body. The first baffle and the second baffle are spaced and arranged inside the return channel and are respectively connected to the inner wall of the valve body. The extending directions of both the first baffle and the second baffle intersect with the extending direction of the return channel. Openings are provided on both the first baffle and the second baffle;

[0017] The valve core includes a first sub - part and a second sub - part. Both the first sub - part and the second sub - part are connected to the driving member. The first sub - part is located between the first baffle and the second sub - part, and the second sub - part is located between the first sub - part and the second baffle;

[0018] The driving member drives the valve core to move unidirectionally to open or close the return valve;

[0019] In the open state, the first sub - part is spaced from the first baffle, the second sub - part is spaced from the second baffle, and the return channel is communicated;

[0020] In the closed state, the first sub - part abuts against the first baffle and is clamped in the corresponding opening, the second sub - part is spaced from the second baffle, or the first sub - part is spaced from the first baffle, the second sub - part abuts against the second baffle and is clamped in the corresponding opening.

[0021] In one embodiment, along the direction in which the first baffle and the first sub - part are arranged, the width of the first sub - part gradually increases;

[0022] Along the direction in which the second baffle and the second sub - part are arranged, the width of the second sub - part gradually increases.

[0023] In one embodiment, the first baffle and the second baffle are arranged in parallel, and the distance between the first baffle and the second baffle is 20 mm to 30 mm.

[0024] In one embodiment, a buffer sub - cavity is formed between the first baffle, the second baffle and the valve body.

[0025] In one embodiment, the volume of the buffer sub - cavity is 8 cm 3 ~11 cm 3 .

[0026] In one embodiment, the area of the opening of the first baffle is 80 square millimeters to 110 square millimeters, and the area of the opening of the second baffle is 80 square millimeters to 110 square millimeters.

[0027] In one embodiment, the coating device further includes a storage tank, and the storage tank has a storage cavity;

[0028] The reflux assembly further includes a first pipeline and a second pipeline. The first pipeline is connected between the reflux port and the inlet of the reflux channel, and the second pipeline is connected between the storage cavity and the outlet of the reflux channel.

[0029] The beneficial effect of the coating device provided by the embodiment of the present application is as follows: By providing a reflux port on the coating die head in the present application, the reflux port is connected to the reflux valve of the reflux assembly. When the slurry flows into the accommodation cavity from the feed port and sprays and starts coating from the discharge port, part of the coating slurry can flow back through the reflux valve to relieve the pressure in the accommodation cavity of the coating die head. The setting of the reflux valve structure and the driving cooperation of the driving member can realize the adjustment of the reflux amount and the reflux speed, thereby actively adjusting the "head thickness" of coating and improving the accuracy of adjustment. In addition, the valve core of the reflux valve makes a reciprocating motion, and the resistance to the reflux motion of the slurry is different when moving forward and backward, and the pressure fluctuation of the coating die head is relatively large. The driving member drives the valve core to move unidirectionally to realize the connection or disconnection of the reflux channel, that is, the valve core moves unidirectionally in one way to complete the opening and closing of the entire reflux valve, avoiding the instability of the slurry flow caused by the reciprocating motion of the valve core and the instability of the pressure in the accommodation cavity of the coating die head, and improving the coating stability and accuracy. Description of the Drawings

[0030] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0031] Figure 1 Structural schematic diagram of a coating device provided by an embodiment of the present application;

[0032] Figure 2 Structural schematic diagram of a coating device provided by another embodiment of the present application;

[0033] Figure 3 Structural schematic diagram of a coating device provided by yet another embodiment of the present application;

[0034] Figure 4 Structural schematic diagram of a coating device provided by still another embodiment of the present application;

[0035] Figure 5 Structural schematic diagram of a coating device provided by yet another embodiment of the present application;

[0036] Among them, the reference numerals in the figures:

[0037] Coating device 100; coating die head 110; reflux assembly 120; storage tank 130; circulation valve 140; control valve 150;

[0038] Reflux valve 121; driving member 122; first pipeline 123; second pipeline 124;

[0039] Valve body A; valve core B; valve body A1; first baffle A2; second baffle A3; first sub - part B1; second sub - part B2; extension direction X of the reflux channel; distance d between the first baffle and the second baffle;

[0040] Accommodation cavity U1; storage cavity U2; reflux port K1; feeding port K2; discharging port K3; opening K4; reflux channel I; buffer sub - cavity II. Detailed implementation manners

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the following further details the present application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0043] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It 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.

[0044] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0045] Please refer to Figures 1 to 5 together, and now the coating device 100 provided by the embodiment of the present application will be described.

[0046] The coating device 100 of the present application is used for coating battery electrodes. As Figure 1 shown, the coating device 100 includes a storage tank 130, a coating valve group, a coating die head 110, and a reflux assembly 120.

[0047] The storage tank 130 has a storage cavity U2 for storing coating slurry. The coating slurry is connected to the coating die head 110 through the coating valve group and is sprayed and coated by the coating die head 110 to form a battery electrode. Specifically, the coating valve group includes a conveying pipeline and a circulation valve 140 and a control valve 150 provided on the conveying pipeline. The circulation valve 140 and the control valve 150 are respectively driven by driving members. The inlet of the circulation valve 140 is connected to the conveying pipeline, and the outlet is connected to the storage tank 130 through a circulation pipeline to return the coating slurry to the storage tank 130. The inlet of the control valve 150 is connected to the conveying pipeline, and the outlet is connected to the coating die head 110 through a connection pipeline. The control valve 150 controls the conveyance and disconnection of the coating slurry to the coating die head 110.

[0048] The coating die head 110 has an accommodation cavity U1 inside. The coating die head 110 is provided with independent reflux ports K1, a feed port K2 and a discharge port K3. The reflux port K1, the feed port K2 and the discharge port K3 are all communicated with the accommodation cavity U1. The outlet of the control valve 150 is connected to the feed port K2 of the coating die head 110 through a connecting pipe. The slurry enters the accommodation cavity U1 through the feed port K2 and is spray-coated through the discharge port K3 to form a pole piece.

[0049] The reflux assembly 120 is connected to the coating die head 110. Specifically, the reflux assembly 120 includes a reflux valve 121, a driving member 122, a first pipe 123 and a second pipe 124. The reflux valve 121 includes a valve body A and a valve core B. The valve body A is connected to the coating die head 110. The valve body A has a reflux channel I, and the inlet of the reflux channel I is communicated with the reflux port K1 of the coating die head 110 through the first pipe 123. The outlet of the reflux channel I is communicated with the storage cavity U2 of the storage tank 130 through the second pipe 124. The valve core B is located in the reflux channel I. The driving member 122 is connected to the valve core B, and the driving member 122 is used to drive the valve core B to move unidirectionally so as to connect or disconnect the reflux channel I.

[0050] During stable coating, the circulation valve 140 is in a closed state, the control valve 150 is in an open state, and the reflux valve 121 is in a closed state. The coating slurry flows through the control valve 150 through the conveying pipe, flows out of the control valve 150 and enters the coating die head 110, and is sprayed from the discharge port K3 of the coating die head 110 to form a pole piece. During stable coating, the flow state of the slurry is relatively stable and the coating quality is high.

[0051] When the coating device 100 performs intermittent coating, the intermittent coating includes a coating stage and an intermittent stage. The intermittent coating repeats the coating stage and the intermittent stage. Therefore, at the moment when coating is started, the pressure in the accommodation cavity U1 of the coating die head 110 suddenly increases. Opening the reflux valve 121 can relieve the pressure at the moment of starting coating.

[0052] Before the intermittent coating is started, the circulation valve 140 is in the open state and the control valve 150 is in the closed state. The coating slurry flows in the conveying pipeline and returns to the storage tank 130 through the circulation valve 140, and no slurry enters the coating die head 110, so no coating is performed. At the moment when the intermittent coating is started for coating, that is, when entering the coating stage, the circulation valve 140 is closed, the control valve 150 is opened, and at the same time the reflux valve 121 is opened. The coating slurry flows in the conveying pipeline, flows into the cavity of the control valve 150, and flows into the coating die head 110 from the outlet of the control valve 150. The slurry flows into the accommodation cavity U1 from the feed inlet K2. Since the reflux valve 121 is opened, part of the slurry refluxes to the slurry pipe through the reflux valve 121, and the rest of the slurry flows out of the coating from the discharge outlet K3, reducing the discharge amount of the discharge outlet K3 of the coating die head 110 and reducing the "head thickness". After the reflux valve 121 adjusts the "head thickness", it is closed, so that the coating enters the stable coating stage, and all the slurry flowing into the accommodation cavity U1 flows out of the discharge outlet K3 for coating. The adjustment of the "head thickness" can be adjusted by the opening speed of the reflux valve 121.

[0053] Optionally, the opening speed of the reflux valve 121 is 40 mm / s to 120 mm / s. Specifically, the opening speed of the reflux valve 121 is 40 mm / s, 50 mm / s, 60 mm / s, 70 mm / s, 80 mm / s, 90 mm / s, 100 mm / s, 110 mm / s or 120 mm / s, etc. In Figure 1 the embodiment, the opening speed of the reflux valve 121 is 100 mm / s, and at this time the initial coating thickness is the smallest.

[0054] After the coating stage is completed, it enters the intermittent stage. In the intermittent stage, the circulation valve 140 is opened, and the control valve 150 and the reflux valve 121 are both closed. No slurry enters the coating die head 110. Subsequently, the coating stage and the intermittent stage are repeated to complete the intermittent coating process.

[0055] In this application, a reflux port K1 is provided on the coating die head 110, and the reflux port K1 is connected to the reflux valve 121 of the reflux assembly 120. When the slurry flows into the accommodation cavity U1 from the feed inlet K2 and starts to coat from the discharge outlet K3, part of the coating slurry can reflux through the reflux valve 121 to relieve the pressure in the accommodation cavity U1 of the coating die head 110. The setting of the structure of the reflux valve 121 and the driving cooperation of the driving member 122 can realize the adjustment of the reflux amount and the reflux speed, so as to actively adjust the coating "head thickness" and improve the accuracy of the adjustment.

[0056] As described in the foregoing coating process, the opening and closing of the reflux valve 121 have a great influence on the coating of the slurry by the coating die head 110, that is, it has a great influence on the quality of the head position of the electrode sheet. If the valve core B of the reflux valve 121 makes a reciprocating motion, the resistance to the reflux motion of the slurry is different when moving forward and backward, and the pressure fluctuation of the coating die head 110 is relatively large. The driving member 122 drives the valve core B to move in one direction, so as to realize the connection or disconnection of the reflux channel I, that is, the valve core B moves in one way and in one direction to complete the opening and closing of the entire reflux valve 121, avoiding the unstable flow of the slurry caused by the reciprocating motion of the valve core B and the unstable pressure of the accommodating cavity U1 of the coating die head 110, and improving the coating stability and accuracy.

[0057] Specifically, as Figure 1 shown, the valve body A includes a valve body A1, a first baffle A2 and a second baffle A3. The reflux channel I is located inside the valve body A1. The first baffle A2 and the second baffle A3 are arranged in parallel at intervals inside the reflux channel I and are respectively connected to the inner wall of the valve body A1. The extending direction of the first baffle A2 and the extending direction of the second baffle A3 both intersect with the extending direction X of the reflux channel I. The first baffle A2 and the second baffle A3 divide the reflux channel I into three regions, and the middle region enclosed by the first baffle A2, the second baffle A3 and the valve body A1 is the buffer sub-cavity II. The valve core B is located between the first baffle A2 and the second baffle A3, and openings K4 are provided on both the first baffle A2 and the second baffle A3. When the reflux valve 121 is opened, the slurry enters the reflux channel I and enters the buffer sub-cavity II from the opening K4 of the first baffle A2, flows out of the buffer sub-cavity II from the opening K4 of the second baffle A3, and then flows out of the reflux valve 121.

[0058] The reflux valve 121 is provided with a buffer sub-cavity II. The slurry flowing back under the pressure of the accommodating cavity U1 of the coating die head 110 enters the buffer sub-cavity II, is blocked by the first baffle A2, and then flows back through the second pipeline 124, which can effectively realize the slurry reflux and reduce the coating instability caused by the slurry flowing back into the accommodating cavity U1 of the coating die head 110. Optionally, the volume of the buffer sub-cavity II is 8 cm 3 ~11 cm 3 , for example, 8 cm 3 , 8.5 cm 3 , 9 cm 3 , 9.5 cm 3 , 10 cm 3 or 11 cm 3 etc. In Figure 1 the embodiment, the volume of the buffer sub-cavity II is 9.5 cm 3 . Setting the volume of the buffer sub-cavity II can adjust the flow rate and velocity of the slurry buffer.

[0059] The driving member 122 drives the valve core B to move in one direction to open or close the reflux valve 121.

[0060] In the open state, the valve core B is spaced from both the first baffle A2 and the second baffle A3, and the reflux channel I is in communication;

[0061] In the closed state, the valve core B abuts against one of the first baffle A2 and the second baffle A3 and is clamped in the corresponding opening K4, that is, the valve core B blocks the opening K4 on one of the first baffle A2 and the second baffle A3, so that the reflux channel I is disconnected, and the valve core B is spaced from the other of the first baffle A2 and the second baffle A3.

[0062] At the beginning of the first coating stage, the driving member 122 drives the valve core B to move in the first direction, the first direction being the direction X in which the reflux channel I extends. The valve core B moves from the opening K4 of the first baffle A2 to the opening K4 of the second baffle A3. During the movement, the reflux channel I is in communication. When the valve core B blocks the opening K4 of the second baffle A3, the reflux channel I is disconnected, and partial reflux of the slurry in the coating die head 110 is completed at the moment of the first start of coating. At the beginning of the next coating stage, the driving member 122 moves in the opposite direction of the first direction, and partial reflux of the slurry in the coating die head 110 is completed at the moment of the next start of coating. The adjustment of the one-way movement of the valve core B further reduces the influence of the reflux valve 121 on the pressure in the coating die head 110.

[0063] Further, the valve core B includes a first sub - part B1 and a second sub - part B2. In Figure 1 the embodiment, the first sub - part B1 and the second sub - part B2 are spaced apart and are both connected to the driving member 122. The first sub - part B1 is located between the second sub - part B2 and the first baffle A2, and the second sub - part B2 is located between the first sub - part B1 and the second baffle A3.

[0064] In the open state, the first sub - part B1 is spaced from the first baffle A2, and the second sub - part B2 is spaced from the second baffle A3, and the reflux channel I is in communication; in the closed state, the first sub - part B1 abuts against the first baffle A2 and the second sub - part B2 is spaced from the second baffle A3, or, the first sub - part B1 is spaced from the first baffle A2 and the second sub - part B2 abuts against the second baffle A3.

[0065] When the distance d between the first baffle A2 and the second baffle A3 is relatively large, the valve core B is provided with the first sub - part B1 and the second sub - part B2, which can reduce the overall volume of the valve core B, thereby reducing the volume occupied by the valve core B in the reflux channel I, further reducing the obstruction to the flow of the reflux slurry, and also facilitating the adjustment of the distance that the reflux valve 121 needs to move to open and close the valve core B.

[0066] Optionally, the distance d between the first baffle A2 and the second baffle A3 is 20 mm to 30 mm, such as 20 mm, 22 mm, 25 mm, 28 mm or 30 mm, etc. It can be understood that setting the distance d between the first baffle A2 and the second baffle A3 can limit the movement of the valve core B between the first baffle A2 and the second baffle A3. If the distance d between the first baffle A2 and the second baffle A3 is too small, it is easy to cause insufficient backflow of the slurry in the coating die head 110, resulting in an overly thick head of the electrode sheet. If the distance is too large, there will be insufficient slurry in the coating die head 110, causing defects or even breaks in the electrode sheet. For example, Figure 1 In an embodiment, the distance d between the first baffle A2 and the second baffle A3 is 25 mm, and the distance between the first sub - part B1 and the second sub - part B2 is 5 mm.

[0067] Optionally, in some embodiments, the first sub - part B1 and the second sub - part B2 can be integrally arranged, making the preparation of the backflow valve 121 simpler, as Figure 2 shown in the embodiment.

[0068] Optionally, the first sub - part B1 and the second sub - part B2 are arranged at intervals, and the opening K4 of the first baffle A2, the opening K4 of the second baffle A3, and the positions of the first sub - part B1 and the second sub - part B2 can be adjusted according to specific circumstances. In Figure 1 the embodiment, the center lines of the opening K4 of the first baffle A2 and the opening K4 of the second baffle A3 overlap, and the center line of the first sub - part B1 overlaps with the center line of the second sub - part B2. Optionally, in Figure 3 the embodiment, the opening K4 of the first baffle A2 and the opening K4 of the second baffle A3 are staggered in the extension direction X of the backflow channel I, and correspondingly, the first sub - part B1 and the second sub - part B2 are staggered in the extension direction X of the backflow channel I.

[0069] Optionally, the area of the opening K4 of the first baffle A2 is 80 square millimeters to 110 square millimeters, such as 80 square millimeters, 85 square millimeters, 90 square millimeters, 95 square millimeters, 100 square millimeters, 105 square millimeters or 110 square millimeters, etc. The area of the opening K4 of the second baffle A3 is 80 square millimeters to 110 square millimeters, such as 80 square millimeters, 85 square millimeters, 90 square millimeters, 95 square millimeters, 100 square millimeters, 105 square millimeters or 110 square millimeters, etc. In Figure 1 the embodiment, the area of the opening K4 of the first baffle A2 is 95 square millimeters, and the area of the opening K4 of the second baffle A3 is 95 square millimeters.

[0070] By setting the area of the opening K4 of the first baffle A2 and the area of the opening K4 of the second baffle A3, the return flow rate and the return flow speed of the slurry can be controlled. When the areas of the opening K4 of the first baffle A2 and the opening K4 of the second baffle A3 are relatively large, the return flow rate of the slurry is large, the pressure relief is rapid, and at the same time, the return flow speed is relatively small, which has little influence on the flow of the slurry in the coating die head 110, further facilitating stable and accurate coating.

[0071] Optionally, in some embodiments, as Figure 4 shown, the area of the opening K4 of the second baffle A3 is larger than the area of the opening K4 of the first baffle A2. The area of the opening K4 of the second baffle A3 is 110 square millimeters, and the area of the opening K4 of the first baffle A2 is 95 square millimeters, so as to increase the return flow rate of the slurry, rapidly relieve the pressure, and reduce the return flow speed.

[0072] Please refer to Figure 5 , optionally, in one embodiment, the first sub - part B1 of the valve core B is located on the side of the first baffle A2 away from the second baffle A3, and the second sub - part B2 is located on the side of the second baffle A3 where the first baffle A2 is located.

[0073] The driving member 122 drives the valve core B to move unidirectionally to open or close the return valve 121.

[0074] In the open state, the first sub - part B1 is spaced from the first baffle A2, the second sub - part B2 is spaced from the second baffle A3, and the return channel I is communicated.

[0075] In the closed state, the first sub - part B1 abuts against the first baffle A2 and is clamped in the corresponding opening K4, the second sub - part B2 is spaced from the second baffle A3, or, the first sub - part B1 is spaced from the first baffle A2, and the second sub - part B2 abuts against the second baffle A3 and is clamped in the corresponding opening K4.

[0076] Driven by the driving member 122, both the first sub - part B1 and the second sub - part B2 move in the first direction or the opposite direction of the first direction. At the beginning of a coating stage, the driving member 122 drives the valve core B to move in the first direction. The distance between the first sub - part B1 and the first baffle A2 gradually decreases until it is clamped at the opening K4 of the first baffle A2, and the second sub - part B2 moves away from the second baffle A3 from the opening K4 of the second baffle A3. During the movement, the return channel I is in communication. When the first sub - part B1 blocks the opening K4 of the first baffle A2, the return channel I is disconnected, completing partial return of the slurry in the coating die head 110 at the moment of starting coating once. At the beginning of the next coating stage, the driving member 122 moves in the opposite direction of the first direction. The distance between the second sub - part B2 and the second baffle A3 gradually decreases until it is clamped at the opening K4 of the second baffle A3, and the first sub - part B1 moves away from the first baffle A2 from the opening K4 of the first baffle A2, completing partial return of the slurry in the coating die head 110 at the moment of starting coating another time.

[0077] Optionally, along the direction in which the first baffle A2 and the first sub - part B1 are arranged, the width of the first sub - part B1 gradually increases. Along the direction in which the second baffle A3 and the second sub - part B2 are arranged, the width of the second sub - part B2 gradually increases. As Figures 1 to 5 shown, both the first sub - part B1 and the second sub - part B2 are frustum - shaped. In Figure 1 the embodiment, the diameter of the upper surface of the first sub - part B1 is larger than the diameter of the lower surface of the first sub - part B1, and the diameter of the upper surface of the second sub - part B2 is smaller than the diameter of the lower surface of the second sub - part B2. The frustum - shaped first sub - part B1 and second sub - part B2, on the one hand, facilitate the insertion of the first sub - part B1 and its being stuck in the opening K4 of the first baffle A2, and facilitate the insertion of the second sub - part B2 and its being stuck in the opening K4 of the second baffle A3; on the other hand, the side surface of the frustum can guide the flow of the slurry, guiding the slurry to flow into the buffer sub - cavity II or flow out of the opening K4 of the second baffle A3 from the buffer sub - cavity II. In Figure 1 the embodiment, the volume of both the first sub - part B1 and the second sub - part B2 is 840 square millimeters. In Figure 5 the embodiment, the diameter of the upper surface of the first sub - part B1 is smaller than the diameter of the lower surface of the first sub - part B1, and the diameter of the upper surface of the second sub - part B2 is larger than the diameter of the lower surface of the second sub - part B2.

[0078] Figure 5 The remaining structure of the coating device 100 provided by the embodiment is similar to that of Figure 1 the embodiment and will not be described in detail here.

[0079] The above is the description of the coating device 100 provided by the embodiments of the present application.

[0080] For the coating device provided by the embodiments of the present application, by providing a reflux port on the coating die head, the reflux port is connected to the reflux valve of the reflux assembly. When the slurry flows into the accommodation cavity from the feed port and sprays for coating from the discharge port, part of the coating slurry can flow back through the reflux valve to relieve the pressure in the accommodation cavity of the coating die head. The setting of the reflux valve structure and the driving - part driving cooperation can realize the adjustment of the reflux amount and the reflux speed, so as to actively adjust the "head thickness" of the coating and improve the accuracy of the adjustment. In addition, the valve core of the reflux valve makes a reciprocating motion, and the resistance to the reflux motion of the slurry is different when moving forward and backward, and the pressure fluctuation of the coating die head is relatively large. The driving part drives the valve core to move unidirectionally to realize the connection or disconnection of the reflux channel, that is, the valve core moves unidirectionally in one way to complete the opening and closing of the entire reflux valve, avoiding the instability of the slurry flow and the instability of the pressure in the accommodation cavity of the coating die head caused by the reciprocating motion of the valve core, and improving the coating stability and accuracy.

[0081] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A coating device for coating battery electrode sheets, characterized in that, The coating device includes: A coating die head, which has a receiving cavity inside. The coating die head is provided with an independent return port, a feeding port, and a discharging port, and the return port, the feeding port, and the discharging port are all communicated with the receiving cavity; and A return assembly, which includes a return valve and a driving member. The return valve includes a valve body and a valve core. The valve body is connected to the coating die head. A return channel communicated with the return port is provided inside the valve body. The valve core is located in the return channel, and the driving member is connected to the valve core. The driving member is used to drive the valve core to move unidirectionally so that the return channel is communicated or disconnected.

2. The coating device according to claim 1, wherein, The valve body includes: A valve body proper, and the return channel is located inside the valve body proper; and A first baffle and a second baffle, which are arranged at intervals in the return channel and are respectively connected to the inner wall of the valve body proper. The extending directions of the first baffle and the second baffle both intersect with the extending direction of the return channel. The valve core is located between the first baffle and the second baffle, and openings are provided on both the first baffle and the second baffle; The driving member drives the valve core to move unidirectionally so that the return valve is opened or closed; In the open state, the valve core is spaced from both the first baffle and the second baffle, and the return channel is communicated; In the closed state, the valve core abuts against one of the first baffle and the second baffle and is clamped in the corresponding opening, and the valve core is spaced from the other of the first baffle and the second baffle, and the return channel is disconnected.

3. The coating device according to claim 2, characterized in that, The valve core includes a first sub - part and a second sub - part. Both the first sub - part and the second sub - part are connected to the driving member. The first sub - part is located between the first baffle and the second sub - part, and the second sub - part is located between the first sub - part and the second baffle; In the open state, the first sub - part is spaced from the first baffle, and the second sub - part is spaced from the second baffle, and the return channel is communicated; In the closed state, the first sub - part abuts against the first baffle and the second sub - part is spaced from the second baffle, or the first sub - part is spaced from the first baffle and the second sub - part abuts against the second baffle.

4. The coating device according to claim 1, wherein The valve body includes a valve body proper, a first baffle and a second baffle. The return channel is located inside the valve body proper. The first baffle and the second baffle are arranged at intervals in the return channel and are respectively connected to the inner wall of the valve body proper. The extending directions of the first baffle and the second baffle both intersect with the extending direction of the return channel, and openings are provided on both the first baffle and the second baffle; The valve core includes a first sub - part and a second sub - part. Both the first sub - part and the second sub - part are connected to the driving member. The first sub - part is located on the side of the first baffle away from the second baffle, and the second sub - part is located on the side of the second baffle where the first baffle is located; The driving member drives the valve core to move unidirectionally so that the return valve is opened or closed; In the open state, the first sub - part is spaced from the first baffle, the second sub - part is spaced from the second baffle, and the reflux channel is in communication; In the closed state, the first sub - part abuts against the first baffle and is clamped in the corresponding opening, the second sub - part is spaced from the second baffle, or the first sub - part is spaced from the first baffle, and the second sub - part abuts against the second baffle and is clamped in the corresponding opening.

5. The coating device according to claim 3 or 4, characterized in that, Along the direction of arrangement of the first baffle and the first sub - part, the width of the first sub - part gradually increases; Along the direction of arrangement of the second baffle and the second sub - part, the width of the second sub - part gradually increases.

6. The coating device according to any one of claims 2 to 4, characterized in that, The first baffle and the second baffle are arranged in parallel, and the distance between the first baffle and the second baffle is 20 mm to 30 mm.

7. The coating device according to any one of claims 2 to 4, characterized in that A buffer sub - cavity is formed between the first baffle, the second baffle and the valve body.

8. The coating device according to claim 7, wherein The volume of the buffer sub-chamber is 8 cm 3 ~11 cm 3 .

9. The coating device according to any one of claims 2 to 4, characterized in that The area of the opening of the first baffle is 80 square millimeters to 110 square millimeters, and the area of the opening of the second baffle is 80 square millimeters to 110 square millimeters.

10. The coating device according to any one of claims 1 to 4, characterized in that, The coating device further includes a storage tank, and the storage tank has a storage cavity; The reflux assembly further includes a first pipe and a second pipe. The first pipe is connected between the reflux port and the inlet of the reflux channel, and the second pipe is connected between the storage cavity and the outlet of the reflux channel.

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