Slurry coating backflow system

Abstract

The utility model discloses a slurry coating backflow system which comprises a buffer tank, a driving device, a coating device, a pressure regulating valve and a control device, the buffer tank is communicated with the coating device or the pressure regulating valve through the driving device, the other end of the pressure regulating valve is communicated with the buffer tank, and the control device is electrically connected with the pressure regulating valve; the control device is used for obtaining the coating pressure of the coating device in the coating state and controlling the pressure adjusting valve to adjust the backflow pressure to be equal to the coating pressure after coating is stopped. And during coating shutdown or intermittent coating, the pressure regulating valve can be controlled by the control device to regulate the backflow pressure to be equal to the coating pressure. Thus, when coating is started again, the temporary storage tank is cut off to supply the slurry to the pressure regulating valve and supply of the slurry to the coating device is recovered, the coating pressure of the coating starting section can be ensured to be normal, so that the surface density in the whole pole piece coating process is equal, the consistency of pole piece coating is ensured, and the coating efficiency is improved. And the yield of the pole piece and the performance of the lithium ion battery can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery production equipment, and particularly relates to a slurry coating and backflow system. BACKGROUND

[0002] Lithium ion batteries have been widely applied in mobile communication devices, portable mobile power storage devices, mine power sources and new energy vehicles due to their high energy density, high working voltage, long cycle life and high safety performance. With the support of the state for the new energy industry, new energy vehicles have become the main trend of future development, and the demand for lithium ion batteries is increasing. Therefore, improving production efficiency has become the primary goal of each enterprise. This is generally achieved by improving process methods and production equipment.

[0003] The coating process of lithium ion batteries is a crucial process in the production of lithium ion batteries. The coating effect directly affects the capacity, internal resistance, cycle life and safety of lithium ion batteries. During the coating process, the equipment is often shut down or the gap is coated. The coating device needs to be withdrawn from the coating roller, and the slurry supply to the coating device is cut off. When the coating is started again, the coating device is aligned with the coating roller, and the slurry is supplied to the coating device for coating. However, when the coating is started again, the slurry supply pressure of the coating section slowly rises and needs a certain time to recover to the normal coating pressure, resulting in a high or low coating area density of the coating section, thereby affecting the yield of the electrode sheet and the performance of the lithium ion battery. CONTENT OF THE INVENTION

[0004] To solve the above-mentioned defects in the prior art, the purpose of the present application is to provide a slurry coating and backflow system. By controlling the backflow pressure to be equal to the coating pressure when the machine is stopped or the coating gap is coated, the coating pressure of the coating section is normal when the coating is started again, thereby ensuring the consistency of the electrode sheet coating and improving the yield of the electrode sheet and the performance of the lithium ion battery.

[0005] The present application provides a slurry coating and backflow system, which comprises a buffer tank, a driving device, a coating device, a pressure regulating valve and a control device. The buffer tank is connected to the coating device or the pressure regulating valve through the driving device. The other end of the pressure regulating valve is connected to the buffer tank. The control device is electrically connected to the pressure regulating valve.

[0006] The control device is used to obtain the coating pressure of the coating device in the coating state, and to control the pressure regulating valve to adjust the backflow pressure to be equal to the coating pressure after the coating is stopped.

[0007] As a preferred embodiment, in the present application, the coating device is provided with a coating pressure sensor for detecting the coating pressure. The coating pressure sensor is electrically connected to the control device.

[0008] As a preferred embodiment, in the present application, the pressure regulating valve is arranged on the return pipeline, the coating device is arranged at the end of the coating pipeline, and the driving device is arranged on the main pipeline, the head end of the main pipeline is communicated with the buffer tank, and the tail end of the main pipeline is communicated with the return pipeline or the coating pipeline.

[0009] As a preferred embodiment, in the present application, a return pressure sensor for detecting the return pressure is arranged on the return pipeline, and the return pressure sensor is electrically connected with the control device.

[0010] As a preferred embodiment, in the present application, a three-way valve is arranged at the tail end of the main pipeline to connect the return pipeline and the coating pipeline respectively, and the three-way valve is electrically connected with the control device.

[0011] As a preferred embodiment, in the present application, the coating device comprises a coating die head, the coating die head comprises an upper die head and a lower die head, the upper die head and the lower die head are oppositely arranged to form an extrusion gap therebetween, one end of the extrusion gap is communicated with the end of the coating pipeline, and the other end of the extrusion gap is a coating port.

[0012] As a preferred embodiment, in the present application, a die cavity is formed in the lower die head towards the upper die head, and the die cavity is connected with the end of the coating pipeline and the coating port through the extrusion gap.

[0013] As a preferred embodiment, in the present application, the die cavity is communicated with the buffer tank through a coating loop, a valve is arranged on the coating loop, and the valve is electrically connected with the control device.

[0014] As a preferred embodiment, in the present application, a magnetic removal device and / or a filtering device are arranged on the main pipeline.

[0015] As a preferred embodiment, in the present application, the buffer tank is provided with a stirring paddle, and the stirring paddle extends from the upper part of the buffer tank into the buffer tank.

[0016] The slurry coating return system provided by the present application has the following technical effects:

[0017] The slurry coating return system is provided with an electrically connected pressure regulating valve and a control device, which can control the coating device to retreat and cut off the supply of slurry to the coating device, and can also control the supply of slurry to the pressure regulating valve to return to the buffer tank, and adjust the return pressure of the pressure regulating valve to be equal to the coating pressure through the control device. In this way, when the coating is started again, the supply of slurry from the buffer tank to the pressure regulating valve is cut off and the supply of slurry to the coating device is restored, which can ensure the normal coating pressure of the starting coating section, so that the area density in the entire coating process of the pole piece is equal, thereby ensuring the consistency of the pole piece coating and improving the yield of the pole piece and the performance of the lithium ion battery. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Structure diagram of slurry coating and reflux system.

[0019] Reference signs:

[0020] 1, buffer tank; 2, driving device; 3, coating device; 31, upper die head; 32, lower die head; 33, extrusion gap; 34, die cavity; 4, pressure regulating valve; 5, coating pressure sensor; 6, reflux pipeline; 7, coating pipeline; 8, main pipeline; 9, reflux pressure sensor; 10, three-way valve; 11, coating loop; 12, valve; 13, demagnetizing device; 14, filtering device; 15, stirring paddle; 16, coating roller. DETAILED DESCRIPTION

[0021] In order to better understand and implement, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application.

[0022] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill 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.

[0024] Referring to Figure 1 The present embodiment provides a slurry coating and reflux system, comprising: a buffer tank 1, a driving device 2, a coating device 3, a pressure regulating valve 4 and a control device, the buffer tank 1 is communicated with the coating device 3 or the pressure regulating valve 4 through the driving device 2, the other end of the pressure regulating valve 4 is communicated with the buffer tank 1, and the control device is electrically connected with the pressure regulating valve 4. The control device is used to obtain the coating pressure of the coating device 3 in the coating state, and control the pressure regulating valve 4 to adjust the reflux pressure to be equal to the coating pressure after the coating is stopped.

[0025] The buffer tank 1 is used to contain the slurry for coating, which can be positive electrode slurry or negative electrode slurry, and the parameters such as solid content and viscosity of the slurry are determined according to the production requirements of the battery electrode sheet. Of course, the coating and reflux system of the present embodiment is only used as an example for the coating of the battery electrode sheet slurry, and as long as the uniform and consistent coating requirement is met, the present device can be used, and only adaptive adjustment is required.

[0026] The slurry in the buffer tank 1 is driven by the driving device 2 to supply to the coating device 3 or the pressure regulating valve 4. Specifically, the slurry is normally coated with a suitable pressure, which is named as "normal coating pressure" in the embodiment, and the normal coating pressure required for different slurries can be different, which can be adjusted by corresponding preset parameters. The normal coating pressure of the same slurry under the same coating requirement is the same. During normal coating, the slurry in the buffer tank 1 is driven by the driving device 2 to supply to the coating device 3, which is arranged close to and aligned with the coating roller 16 to extrude the slurry at the normal coating pressure and coat on the current collector of the coating roller 16, and the control device can obtain the specific value of the normal coating pressure. When stop or gap coating, the coating needs to be stopped and the coating device 3 is away from the coating roller 16, at this time the buffer tank 1 stops supplying the slurry to the coating device 3, but supplies the slurry to the pressure regulating valve 4 through the driving device 2, and returns to the buffer tank 1 through the pressure regulating valve 4. During the supply of the slurry to the pressure regulating valve 4, the control device controls the pressure regulating valve 4 to adjust the return pressure to be equal to the normal coating pressure, so that when the coating is resumed, the buffer tank 1 stops supplying the slurry to the pressure regulating valve 4, and supplies the slurry to the coating device 3 through the driving device 2, and the coating pressure of the coating device 3 during the start-up section of the coating when it is close to and aligned with the coating roller 16 is the normal coating pressure, so as to ensure that the coating device 3 can always coat at the normal coating pressure regardless of the presence of stop or gap coating conditions, thereby ensuring that the area density is equal during the entire process of coating the pole piece.

[0027] It should be noted that the coating device 3 is away from the coating roller 16 to stop coating, which is divided into two cases, the first case is gap coating, that is, the coating device 3 is away from the coating roller 16 at the coating gap, and the entire coating return system does not stop, but supplies the slurry to the pressure regulating valve 4, at this time the control device controls the return pressure of the pressure regulating valve 4 to be equal to the normal coating pressure, so as to ensure that the coating pressure of the coating device 3 during the start-up section of the coating when it is close to and aligned with the coating roller 16 is the normal coating pressure when the coating is resumed across the gap. The second case is stop, that is, the coating device 3 needs to be cleaned, the equipment fails or other reasons, and the entire coating return system needs to be stopped during coating, at this time the buffer tank 1 neither supplies the slurry to the coating device 3 nor supplies the slurry to the pressure regulating valve 4. The control device has a memory function, which can record the normal coating pressure of the coating device 3 during coating, so as to supply the slurry in the buffer tank 1 to the pressure regulating valve 4 for return circulation flow through the driving device 2 when restarting, and control the pressure regulating valve 4 to adjust the return pressure to be equal to the normal coating pressure through the control device, and then replace the slurry to supply to the coating device 3, so as to realize the coating of the coating device 3 at the normal coating pressure.

[0028] Of course, the above two cases are in the coating process, coating conditions also exist another case that the initial coating, also need to ensure the normal coating pressure of the start-up. Specifically, before the coating starts, the control device is set to the normal coating pressure value, coating backflow system starts, first the buffer tank 1 slurry through the drive device 2 is supplied to the pressure regulating valve 4 for backflow circulation flow, and through the control device control pressure regulating valve 4 adjustment backflow pressure equal to the set normal coating pressure, after the pressure adjustment, can replace the slurry to the coating device 3 supply, so as to realize the coating device 3 with normal coating pressure start coating.

[0029] Wherein, the start-up refers to the start of each coating device 3 close to the coating roller 16 coating phase, including the initial coating, gap after the resumption of coating, after the resumption of coating and so on. The pressure adjustment throughout the coating process by the control device to deploy, the control device can control the entire system, including pressure adjustment, shutdown, start, drive device 2 drive and so on. Drive device 2 for the entire system slurry drive flow, it can be screw pump, gear pump, vane pump and so on.

[0030] Based on this, the slurry coating backflow system is provided with an electrically connected pressure regulating valve 4 and control device, in the coating stop or gap coating, both can control the coating device 3 away from the coating roller 16 and cut off the supply of slurry to the coating device 3, and can control the slurry to the pressure regulating valve 4 supply to backflow to the buffer tank 1, and through the control device control pressure regulating valve 4 adjustment backflow pressure equal to the normal coating pressure. So, when starting the coating again, cut off the buffer tank 1 to the pressure regulating valve 4 supply slurry and restore the supply of slurry to the coating device 3, can ensure the normal coating pressure of the start-up, so that the surface density of the pole piece in the whole process of coating is equal, thereby ensuring the consistency of the pole piece coating, is conducive to improve the yield of the pole piece and the performance of the lithium ion battery.

[0031] The coating device 3 is provided with a coating pressure sensor 5 for detecting the coating pressure, and the coating pressure sensor 5 is electrically connected with the control device. The coating pressure sensor 5 is used for detecting the normal coating pressure of the coating device 3, and feeding the normal coating pressure value to the control device, so that the control device can control the pressure regulating valve 4 to adjust the backflow pressure according to the normal coating pressure feedback by the coating pressure sensor 5, so that the backflow pressure is equal to the normal coating pressure, thereby ensuring the consistency of the pole piece slurry coating.

[0032] The pressure regulating valve 4 is arranged on the return pipeline 6, the coating device 3 is arranged at the end of the coating pipeline 7, and the driving device 2 is arranged on the main pipeline 8, the head end of the main pipeline 8 is communicated with the buffer tank 1, and the tail end of the main pipeline 8 is communicated with the return pipeline 6 or the coating pipeline 7. The slurry in the buffer tank 1 is driven by the driving device 2 to flow to the main pipeline 8, and is selectively flowed to the coating pipeline 7 or the return pipeline 6 according to the coating working condition, so as to be flowed to the coating device 3 for coating or returned to the buffer tank 1 after the return pressure is adjusted by the pressure regulating valve 4.

[0033] The tail end of the main pipeline 8 is provided with a three-way valve 10 to be connected with the return pipeline 6 and the coating pipeline 7 respectively, and the three-way valve 10 is electrically connected with the control device. The three-way valve 10 is provided with an inlet, a first outlet and a second outlet, the inlet is connected with the tail end of the main pipeline 8, the first outlet is connected with the coating pipeline 7, and the second outlet is connected with the return pipeline 6. In normal coating, the control device controls the inlet to be communicated with the first outlet, so that the slurry in the buffer tank 1 is driven by the driving device 2 to flow to the coating device 3 through the main pipeline 8 and the coating pipeline 7 in sequence for coating. In shutdown or gap coating, the control device controls the inlet to be communicated with the second outlet, so that the slurry in the buffer tank 1 is driven by the driving device 2 to flow to the buffer tank 1 through the main pipeline 8 and the return pipeline 6 in sequence, and in the process, the return pressure is adjusted by the control device to be equal to the normal coating pressure by controlling the pressure regulating valve 4.

[0034] The return pipeline 6 is provided with a return pressure sensor 9 for detecting the return pressure, and the return pressure sensor 9 is electrically connected with the control device. The return pressure sensor 9 is used for detecting the return pressure of the return pipeline 6 in the return working condition and feeding back to the control device, and the control device can control the pressure regulating valve 4 to adjust the return pressure according to the value fed back by the return pressure sensor 9, so that the return pressure is equal to the normal coating pressure.

[0035] The coating device 3 comprises a coating die head, the coating die head comprises an upper die head 31 and a lower die head 32, the upper die head 31 and the lower die head 32 are oppositely arranged to form an extrusion gap 33 between them, one end of the extrusion gap 33 is communicated with the end of the coating pipeline 7, and the other end of the extrusion gap 33 is a coating port 34. The slurry in the buffer tank 1 is driven by the driving device 2 to flow to the extrusion gap 33 through the main pipeline 8 and the coating pipeline 7 in sequence, and then extruded through the coating port 34 to be coated on the current collector of the coating roller 16.

[0036] The lower die head 32 is provided with a die cavity 35 facing the upper die head 31, and the die cavity 35 is connected with the end of the coating pipeline 7 and the coating port 34 through the extrusion gap 33. The die cavity 35 can store a small amount of slurry and uniformly spread the slurry in the width direction, so that the slurry can be uniformly coated in the width direction when extruded through the coating port 34, further improving the consistency of the pole piece slurry coating.

[0037] The die cavity 35 is communicated with the buffer tank 1 through the coating circuit 11, and the coating circuit 11 is provided with a valve 12, which is electrically connected with the control device. When it is needed to stop and clean the coating device 3, the control device controls the buffer tank 1 to supply the slurry to the return pipeline 6, and controls the valve 12 to be opened so that the slurry in the die cavity 35 returns to the buffer tank 1, thereby cleaning the coating device 3. In the normal coating, the valve 12 is closed.

[0038] In addition, the main pipeline 8 is provided with a demagnetizing device 13 and / or a filtering device 14. The demagnetizing device 13 can be an existing demagnetizing machine to remove metal impurities such as iron in the slurry. The filtering device 14 includes a filter element to remove impurity particles in the slurry. The demagnetizing device 13 and the filtering device 14 can be provided with only one or both to ensure the quality of the slurry and the yield of the coating. Generally, the demagnetizing device 13 is provided before the filtering device 14, and the larger metal particles are removed by the demagnetizing device 13, and then the small impurity particles are removed by the filtering device 14, thereby ensuring efficient removal of impurities and avoiding the large metal particles from blocking the filtering device 14 to affect the filtering effect. Of course, the positions of the two can be interchanged according to the actual working condition.

[0039] The buffer tank 1 is provided with a stirring paddle 15, which extends downward from the upper part of the buffer tank 1 into the buffer tank 1. The stirring paddle 15 can continuously stir the slurry to prevent the slurry in the buffer tank 1 from depositing to affect the quality such as the solid content.

[0040] The technical means disclosed in the application scheme is not limited to the technical means disclosed in the above-mentioned embodiments, but also includes the technical solutions composed of any combination of the above technical features. It should be noted that for ordinary skilled persons in the art, without departing from the principles of the application, some improvements and refinements can also be made, which are also considered within the protection scope of the application.

Claims

1. A paste coating reflow system characterized by, The application relates to a coating device comprising a buffer tank (1), a driving device (2), a coating device (3), a pressure regulating valve (4) and a control device, wherein the buffer tank (1) is connected to the coating device (3) or the pressure regulating valve (4) through the driving device (2), the other end of the pressure regulating valve (4) is connected to the buffer tank (1), and the control device is electrically connected to the pressure regulating valve (4). The control device is used to obtain the coating pressure of the coating device (3) under the coating state, and to control the pressure regulating valve (4) to adjust the backflow pressure to be equal to the coating pressure after the coating is stopped. The coating device (3) is provided with a coating pressure sensor (5) used for detecting the coating pressure, and the coating pressure sensor (5) is electrically connected to the control device.

2. The paste coating reflow system of claim 1, wherein: The pressure regulating valve (4) is arranged on a backflow pipeline (6), the coating device (3) is arranged at the end of a coating pipeline (7), the driving device (2) is arranged on a main pipeline (8), the front end of the main pipeline (8) is connected to the buffer tank (1), and the tail end of the main pipeline (8) is connected to the backflow pipeline (6) or the coating pipeline (7).

3. The paste coating reflow system of claim 1 or 2, wherein: A backflow pressure sensor (9) used for detecting the backflow pressure is arranged on the backflow pipeline (6), and the backflow pressure sensor (9) is electrically connected to the control device.

4. The paste coating reflow system of claim 3, wherein: A three-way valve (10) is arranged at the tail end of the main pipeline (8) to be connected to the backflow pipeline (6) and the coating pipeline (7) respectively, and the three-way valve (10) is electrically connected to the control device.

5. The paste coating reflow system of claim 3, wherein: The coating device (3) comprises a coating die head, the coating die head comprises an upper die head (31) and a lower die head (32), the upper die head (31) and the lower die head (32) are oppositely arranged to form an extrusion gap (33) between the two, one end of the extrusion gap (33) is connected to the end of the coating pipeline (7), and the other end of the extrusion gap (33) is a coating port (34).

6. The paste coating reflow system of claim 3, wherein: The lower die head (32) is provided with a die cavity (35) facing the upper die head (31), and the die cavity (35) is connected to the end of the coating pipeline (7) and the coating port (34) through the extrusion gap (33).

7. The paste coating reflow system of claim 6, wherein: The die cavity (35) is connected to the buffer tank (1) through a coating loop (11), a valve (12) is arranged on the coating loop (11), and the valve (12) is electrically connected to the control device.

8. The paste coating reflow system of claim 7, wherein: A demagnetization device (13) and / or a filtering device (14) are arranged on the main pipeline (8).

9. The paste coating reflow system of claim 3, wherein: The buffer tank (1) is provided with a stirring paddle (15) extending from the upper end of the buffer tank (1) to the inside of the buffer tank (1).

10. The paste coating reflow system of claim 1 or 2, wherein: ​

Images