Patent Description:
This application relates to the technical field of coating, and in particular, to a coating system.

In an electrode plate coating process of a lithium battery, a single-layer and single-cavity coating head is used for coating, and a slurry is continuously sprayed on a current collector through a lip of the coating head, so as to achieve uniformity and consistency of areal density of a film. However, when a coating thickness is constant, a cavity pressure of the single-layer coating head is high, and is prone to abrade the lip and result in weight fluctuation during coating. Therefore, in the prior art, the slurry is applied on the current collector in a plurality of layers for several times to form a coating thickness on the current collector. In this way, the pressure in the cavity of the coating head is relatively low each time of coating, and the lip abrasion is reduced. However, because different layers of coating are formed at intervals, the layers are bonded inferiorly and prone to peel off from each other.

<CIT> relates to a continuous coating method in which a positive electrode coating material or a negative electrode coating material is discharged from a slit of a die head onto the surface of a substrate held and transported by a coating roll and a coating film is formed on almost the entire surface, or by continuous opening or closing of the valve intermittently. <CIT> relates to a vacuum chamber system of a coating apparatus and a coating method using the same that prevents the attraction phenomenon of a coating solution in intermittent coating, so that the failure rate of coating is reduced, thereby improving the quality of products. <CIT> relates to a slot die coater adjustment device and a slot die coater adjustment system including the same, more specifically, by moving the upper die of the slot die coater in the front-rear direction to increase the distance between the upper and lower discharge ports of the slot die coater. <CIT> relates to an active material layer forming apparatus such as a lithium ion secondary battery in which a solid electrolyte layer is interposed between active material layers, an active material layer forming method, and a battery manufacturing method. <CIT> relates to fabricating apparatus of cell electrode and fabricating method of cell electrode. <CIT> relates to a coating apparatus for applying a coating liquid to a long web.

Embodiments of this application provide a coating system to improve performance of bonding between layers of multi-layer coating.

An embodiment of this application provides a coating system according to the claim <NUM> of the present application.

In the foregoing technical solution, the coating head is equipped with a plurality of dispensing cavities that each include a coating opening. Each dispensing cavity can perform a layer of coating correspondingly. Therefore, the same coating head can implement multi-layer coating, and can spread the slurry on the substrate in a plurality of layers for several times to form a given coating thickness on the substrate. In this way, the pressure in each dispensing cavity of the coating head each time of coating is lower than the pressure generated when the slurry is concentrated in one dispensing cavity, thereby reducing lip abrasion. In addition, the same coating head implements all layers of coating, so that different layers of coating are formed at relatively short intervals. In this way, all layers of coating can be implemented simultaneously, and the slurry flowing out of each coating opening can be bonded and attached at the lip of the coating head first, and then spread onto the substrate, so that different layers are bonded to each other more effectively and not prone to peel off from each other. In addition, the valve disposed between at least one dispensing cavity and the feeding apparatus enables the coating system to implement local thin-coating.

In the foregoing technical solution, the coating head includes a lower die, a middle die, and an upper die. After being combined, the middle die and the upper die form a dispensing cavity, and the middle die and the lower die form another dispensing cavity. In this way, it is convenient to disassemble the coating head for cleaning the interior of the dispensing cavity and replacing parts in the dispensing cavity.

In some embodiments of this application, the coating system further includes a back roller. The back roller is configured to drive the substrate. An out-feed direction of each coating opening coincides with an extension direction of a diameter of the back roller.

In the foregoing technical solution, the out-feed direction of the coating opening is along a diameter direction of the back roller, thereby preventing the lip of the coating head from scraping the slurry.

In some embodiments of this application, an out-feed direction of the coating opening of one of the at least two dispensing cavities is arranged horizontally.

In the foregoing technical solution, the out-feed direction of one of the coating openings of the coating head is arranged horizontally, thereby preventing the lip of the coating head from scraping the slurry. The coating head vibrates up and down during a coating operation. The horizontally arranged coating opening vibrates up and down along with the coating head. In this way, the horizontally arranged coating opening changes positions merely in the vertical direction, but a horizontal distance between the coating opening and a center of the back roller remains unchanged, thereby avoiding an impact on the coating thickness of the slurry out of the coating opening, and helping to ensure coating quality.

In some embodiments of this application, the coating system further includes an adsorption apparatus. The adsorption apparatus is configured to keep an air pressure stable at the coating opening.

In the foregoing technical solution, the adsorption apparatus can keep the air pressure stable at the coating opening, so as to prevent the slurry at the coating opening from being affected by air flow fluctuations, increase affinity between the slurry and the substrate, increase coating uniformity, and in turn, improve the coating quality.

In some embodiments of this application, the coating system further includes a marking apparatus. The marking apparatus is located downstream of the coating head, and the marking apparatus is configured to mark an uncoated region of the substrate to identify a thin-coated position or an uncoated position.

In the foregoing technical solution, the disposed marking apparatus can mark the uncoated region of the substrate, so as to identify the thin-coated position or uncoated position and provide accurate positioning for subsequent die-cutting.

In some embodiments of this application, the coating head further includes two spacers. The two spacers are disposed between the upper die and the middle die, and between the middle die and the lower die, respectively. The coating opening is disposed at the spacer.

In the foregoing technical solution, the thickness of the spacer can affect the coating thickness at the coating opening, and in turn, affect the coating weight. The coating weight can be adjusted by disposing spacers of different thicknesses between the upper die and the middle die, and between the middle die and the lower die, respectively.

In some embodiments of this application, the upper die is pivotally connected to the middle die, and the middle die is pivotally connected to the lower die. The coating head further includes a first die-clamping piece and a second die-clamping piece. The first die-clamping piece is configured to fix the upper die and the middle die when clamping the upper die to the middle die. The second die-clamping piece is configured to fix the middle die and the lower die when clamping the middle die to the lower die.

In the foregoing technical solution, the upper die is pivotally connected to the middle die, and the middle die is pivotally connected to the lower die, so that all components of the coating head are always connected together, and it is ensured that the relative position between the lower die, the middle die, and the upper die is fixed. In clamping the lower die to the middle die or clamping the middle die to the upper die, the two dies can be clamped together accurately without a need to recalibrate the positions of the dies. The first die-clamping piece and the second die-clamping piece can implement firm connection between the upper die and the middle die, and between the middle die and the lower die, respectively, so as to ensure stability of pressure and flow speed of the slurry in the two dispensing cavities, and in turn, improve the coating quality.

In some embodiments of this application, the number of the feeding apparatuses is at least two, and the feeding apparatuses are in one-to-one correspondence with the dispensing cavities. Each feeding apparatus includes a tank and a feeding pump. The feeding pump is configured to pump the slurry in the tank to the dispensing cavity.

In the foregoing technical solution, the feeding apparatuses are in one-to-one correspondence with the dispensing cavities, making it convenient to independently control the feeding speed and pressure of each dispensing cavity.

In some embodiments of this application, the valve includes a valve body, a first valve core, a second valve core, a first drive component, and a second drive component. The valve body includes an in-feed port, a back-feed port, and an out-feed port. The out-feed port communicates with the dispensing cavity, the in-feed port communicates with an outlet of the feeding pump, and the back-feed port communicates with the tank. The first drive component is configured to drive the first valve core to move in the valve body, so as to implement communication or disconnection between the in-feed port and the out-feed port. The second drive component is configured to drive the second valve core to move in the valve body, so as to implement communication or disconnection between the out-feed port and the back-feed port.

In the foregoing technical solution, the movement of the first valve core can implement communication or disconnection between the in-feed port and the out-feed port. The communication between the in-feed port and the out-feed port enables coating. The movement of the second valve core can implement communication or disconnection between the out-feed port and the back-feed port. At positions intended to be thin-coated or uncoated, through the second valve core and the communication between the out-feed port and the back-feed port, the slurry inside corresponding dispensing cavity can flow back to the tank to prevent the remaining slurry in the dispensing cavity from affecting uncoating or thin coating. In other words, the valve can feed the slurry to the coating head, and can also implement backflow of the slurry. When no coating is required, the slurry can flow back in time to prevent the slurry in the dispensing cavity from affecting effects of clearance coating or local thin coating.

To describe technical solutions in embodiments of this application more clearly, the following outlines the drawings to be used in the embodiments. Understandably, the following drawings show merely some embodiments of this application, and therefore, are not intended to limit the scope. A person of ordinary skill in the art may derive other related drawings from the drawings without making any creative efforts.

Reference numerals: <NUM>-coating system; <NUM>-coating head; <NUM>-dispensing cavity; 11a-first dispensing cavity; 11b-second dispensing cavity; <NUM>-upper die; <NUM>-first groove; <NUM>-first in-feed port; <NUM>-first exhaust port; <NUM>-auxiliary exhaust port; <NUM>-middle die; <NUM>-second groove; <NUM>-second exhaust port; <NUM>-lower die; <NUM>-second in-feed port; <NUM>-third groove; <NUM>-fourth groove; <NUM>-spacer; <NUM>-pressure plate; <NUM>-first hinge; <NUM>-second hinge; <NUM>-first die-clamping piece; <NUM>-second die-clamping piece; <NUM>-fixing back plate; <NUM>-flip lever; <NUM>-tuning mechanism; <NUM>-fixing plate; <NUM>-fastening screw; <NUM>-tuning push-pull rod; <NUM>-adhesive dispensing valve; <NUM>-feeding apparatus; <NUM>-tank; <NUM>-feeding pump; <NUM>-valve; <NUM>-valve body; <NUM>-in-feed port; <NUM>-out-feed port; <NUM>-back-feed port; <NUM>-first valve core; <NUM>-second valve core; <NUM> -first drive component; <NUM>-second drive component; <NUM>-first sealing structure; <NUM>-second sealing structure; <NUM>-marking apparatus; <NUM>-damper; <NUM>-first filter; <NUM>-second filter; <NUM>-delivery system; <NUM>-back roller; <NUM>-adsorption apparatus; <NUM>-flowmeter; <NUM>-pressure sensor; <NUM>-substrate; <NUM>-coating measurement system; C-horizontal direction; D-coating width direction of coating opening.

To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following gives a clear and complete description of the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Apparently, the described embodiments are merely a part of but not all of the embodiments of this application. The components described and illustrated in the drawings according to the embodiments of this application generally may be arranged and designed in a variety of different configurations.

Therefore, the following detailed description of the embodiments of this application provided with reference to the drawings is not intended to limit the scope of this invention as claimed, but merely represents selected embodiments of this application. All other embodiments derived by a person of ordinary skill in the art based on the embodiments of this application without making any creative efforts fall within the protection scope of this invention, which is defined by the appended claims.

It is hereby noted that to the extent that no conflict occurs, the embodiments of this application and the features in the embodiments may be combined with each other.

It is hereby noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, the item does not need to be further defined or construed in subsequent drawings.

In the description of the embodiments of this application, it is hereby noted that an indicated direction or positional relationship is a direction or positional relationship based on illustration in the drawings, or a direction or positional relationship by which a product in use according to this application is usually placed, or a direction or positional relationship commonly understood by a person skilled in the art, and is merely intended for ease or brevity of describing this application, but does not indicate or imply that the indicated apparatus or component is necessarily located in the specified direction or constructed or operated in the specified direction. Therefore, the indicated direction or positional relationship is never to be understood as a limitation on this application. In addition, the terms "first", "second", and "third" are merely intended for distinct description, but not intended to indicate or imply order of precedence.

With the application and popularization of lithium-ion batteries in the fields such as communications, portable electronic products, electric vehicles, aerospace, watercraft, especially in the field of electric vehicles, requirements for a high cruising range and high safety performance are more intense, and higher requirements have been put forward on an electrode plate coating process of lithium-ion power batteries.

The coating technology of an extrusion coater is becoming mature, and has become a mainstream technique in the coating production process of lithium batteries.

Initially, power battery manufacturers use a single-layer and single-cavity coating head to coat a lithium-ion electrode plate in a coating process, and a slurry is continuously sprayed on a substrate through a lip of the coating head, so as to achieve uniformity and consistency of areal density of a film. The pressure in a cavity of the single-layer and single-cavity coating head is high, and is prone to cause lip abrasion. In addition, the process of abrading the lip leads to weight fluctuations during the coating, and the coating slurry is excessively thinned at the lip. The excessively thin slurry induces a safety hazard of lithium plating during charge-and-discharge cycles of a lithium-ion battery.

Therefore, another practice is put forward in which the same weight of coating slurry is spread onto the substrate in a plurality of layers through a plurality of coating heads. This practice not only ensures an appropriate coating weight but also reduces the slurry pressure in the cavity of each coating head, thereby reducing lip abrasion. However, this leads to a time difference between the coating heads, and the layers are bonded to each other inferiorly and prone to peel off from each other.

In view of this, an embodiment of this application provides a coating system <NUM>, configured to coat a substrate <NUM> to form an electrode plate. A plurality of dispensing cavities <NUM> that each include a coating opening are disposed on the coating head <NUM>. A valve <NUM> is disposed between at least one dispensing cavity <NUM> and a feeding apparatus <NUM>, so that the coating system <NUM> can not only implement multi-layer coating to reduce abrasion of the lip of the coating head <NUM>, but also implement clearance coating and thin coating.

It is hereby noted that the substrate <NUM> is a current collector of the electrode plate.

Referring to <FIG> is a schematic diagram of a coating system <NUM> according to an embodiment of this application, and <FIG> is a simplified block diagram of the coating system <NUM> shown in <FIG>. The coating system <NUM> includes a coating head <NUM>, a feeding apparatus <NUM>, and a valve <NUM>. The coating head <NUM> is equipped with at least two dispensing cavities <NUM> independent of each other. Each dispensing cavity <NUM> includes a coating opening. The feeding apparatus <NUM> is connected to the dispensing cavity <NUM>. The feeding apparatus <NUM> is configured to feed a slurry to the dispensing cavity <NUM>. The valve <NUM> is disposed between at least one dispensing cavity <NUM> and the feeding apparatus <NUM>, and the valve <NUM> is configured to implement communication or disconnection between a corresponding dispensing cavity <NUM> and the feeding apparatus <NUM>.

The coating head <NUM> is equipped with a plurality of dispensing cavities <NUM> that each include a coating opening. Each dispensing cavity <NUM> can perform a layer of coating correspondingly. Therefore, the same coating head <NUM> can implement multi-layer coating, and can spread the slurry on the substrate <NUM> in a plurality of layers for several times to form a given coating thickness on the substrate <NUM>. In this way, the pressure in each dispensing cavity <NUM> of the coating head <NUM> each time of coating is lower than the pressure generated when the slurry is concentrated in one dispensing cavity <NUM>, thereby reducing lip abrasion. If the size of the coating opening is designed to be relatively large, the coating weight can be increased, and the capacity of the lithium battery can be increased.

In addition, the same coating head <NUM> implements all layers of coating, so that different layers of coating are formed at relatively short intervals. In this way, all layers of coating can be implemented simultaneously, and the slurry flowing out of each coating opening can be bonded and attached at the lip of the coating head <NUM> first, and then spread onto the substrate <NUM>, so that different layers are bonded to each other more effectively and not prone to peel off from each other.

In addition, the valve <NUM> disposed between at least one dispensing cavity <NUM> and the feeding apparatus <NUM> enables the coating system <NUM> to implement local thin-coating.

In some embodiments, as shown in <FIG>, the valve <NUM> is disposed between each dispensing cavity <NUM> and the feeding apparatus <NUM>. If each valve <NUM> keeps communication between the corresponding dispensing cavity <NUM> and the feeding apparatus <NUM>, the coating can be implemented at each coating opening. If some of the valves <NUM> intermittently disconnect the corresponding dispensing cavity <NUM> from the feeding apparatus <NUM> and the remaining valves <NUM> always keep communication between the corresponding dispensing cavity <NUM> and the feeding apparatus <NUM>, the coating head <NUM> can implement local thin-coating. If all the valves <NUM> intermittently disconnect the corresponding dispensing cavity <NUM> from the feeding apparatus <NUM>, the substrate <NUM> can be partly uncoated, that is, locally intermittent coating.

In some embodiments, as shown in <FIG>, the valve <NUM> is disposed between just one dispensing cavity <NUM> and the feeding apparatus <NUM>, and the valve <NUM> is not disposed between other dispensing cavities <NUM> and the feeding apparatus <NUM>. In this case, the valve <NUM> can intermittently disconnect the corresponding dispensing cavity <NUM> from the feeding apparatus <NUM> to thinly coat the substrate <NUM> locally. If the valve <NUM> always disconnects the corresponding dispensing cavity <NUM> from the feeding apparatus <NUM>, the substrate <NUM> can be entirely thin-coated.

In some embodiments, the number of the feeding apparatuses <NUM> is at least two, and the feeding apparatuses <NUM> are in one-to-one correspondence with the dispensing cavities <NUM>. Each feeding apparatus <NUM> includes a tank <NUM> and a feeding pump <NUM>. The feeding pump <NUM> is configured to pump the slurry in the tank <NUM> to the dispensing cavity <NUM>. The feeding apparatuses <NUM> are in one-to-one correspondence with the dispensing cavities <NUM>, making it convenient to independently control the feeding speed and pressure of each dispensing cavity <NUM>. The feeding pump <NUM> is a screw pump.

In some embodiments, depending on the number of dispensing cavities <NUM>, the number of feeding apparatuses <NUM> is adjusted, so that the feeding apparatuses <NUM> are in one-to-one correspondence with the dispensing cavities <NUM>. For example, if the number of dispensing cavities <NUM> is three, the number of feeding apparatuses <NUM> is set to three correspondingly.

In some embodiments, the number of feeding apparatus <NUM> may be one, and each dispensing cavity <NUM> is fed with the slurry by the same feeding apparatus <NUM>.

In some embodiments, as shown in <FIG>, the feeding apparatus <NUM> may include a tank <NUM> and a plurality of feeding pumps <NUM>. The feeding pumps <NUM> are in one-to-one correspondence with the dispensing cavities <NUM>. Each feeding pump <NUM> is configured to pump the slurry in the tank <NUM> into the corresponding dispensing cavity <NUM>.

In some embodiments, the coating system <NUM> further includes a marking apparatus <NUM>. The marking apparatus <NUM> is located downstream of the coating head, and the marking apparatus <NUM> is configured to mark an uncoated region of the substrate <NUM> to identify a thin-coated position or an uncoated position. To be specific, the marking apparatus <NUM> marks the uncoated region of the coated substrate <NUM> to identify a thin-coated position or uncoated position, so as to provide precise positioning for subsequent die-cutting. Definitely, the marking apparatus <NUM> may work together with the valve <NUM> to implement closed-loop control through a programmable logic controller (PLC), and mark a specified clearance position (uncoated position) or thin-coated position to enable precise detection and identification of a die-cutting position of a tab to be cut subsequently, so that a clearance position or thin-coated position is a preset position of a wound electrode plate. The marking apparatus <NUM> includes, but is not limited to, an ink jet apparatus. It is hereby noted that "downstream" means a later step of a processing process, and "a marking step performed downstream of the coating head <NUM>" means a marking step performed after the coating step.

In some embodiments, the coating system <NUM> further includes a damper <NUM>. The damper <NUM> is configured to balance pressure fluctuations during the flow of the slurry, and make the slurry flow steadily. The damper <NUM> may be a pulsation damper <NUM>. The pulsation damper <NUM> is an apparatus specially designed to smoothly pulsate to accumulate pressurized liquid. The pulsation damper <NUM> may be a gasbag-type pulsation damper or a straight-through pulsation damper. The gasbag-type pulsation damper can achieve the purpose of storing and releasing energy by using compressibility of gas.

In some embodiments, the damper <NUM> is disposed between the tank <NUM> and the feeding pump <NUM>. The damper <NUM> can eliminate the fluctuation of the feeding pressure caused by the change of the liquid level of the slurry in a bucket, and make the slurry in the feeding pump <NUM> flow steadily.

In some embodiments, the damper <NUM> is disposed between the feeding pump <NUM> and the valve <NUM>. The damper <NUM> can eliminate the feeding pressure fluctuations induced by the feeding pump <NUM> and a movement impact induced by the opening and closing of the valve <NUM>.

In some embodiments, the damper <NUM> may be disposed between the tank <NUM> and the feeding pump <NUM>, and between the feeding pump <NUM> and the valve <NUM> concurrently.

In some embodiments, the damper <NUM> is disposed between the valve <NUM> and the coating head <NUM>. The damper <NUM> can eliminate the feeding pressure fluctuations occurring before the slurry enters the coating head <NUM>. In addition, a flowmeter <NUM> may be used to monitor a pump flow in real time, and work together with a coating measurement system <NUM> to implement closed-loop control and adjust a pump speed of the feeding pump <NUM> according to the coating situation.

In some embodiments, the damper <NUM> may be disposed between the tank <NUM> and the feeding pump <NUM>, between the feeding pump <NUM> and the valve <NUM>, and between the valve <NUM> and the coating head <NUM> concurrently. Alternatively, the damper <NUM> may be disposed between the feeding pump <NUM> and the valve <NUM>, and between the valve <NUM> and the coating head <NUM>.

In some embodiments, the coating system <NUM> further includes a first filter <NUM>. The first filter <NUM> is disposed between the feeding pump <NUM> and the valve <NUM>, or the first filter <NUM> is disposed between the valve <NUM> and the coating head <NUM>, or the first filter <NUM> is disposed between the pump and the valve <NUM>, and between the valve <NUM> and the coating head <NUM> concurrently, so that the slurry pumped out of the tank <NUM> enters the dispensing cavity <NUM> of the coating head <NUM> after being filtered by the first filter <NUM>. The first filter <NUM> disposed improves the filtering effect of the slurry. The improved filtering effect of slurry particles improves the coating quality significantly.

When the damper <NUM> is disposed between the tank <NUM> and the feeding pump <NUM>, the first filter <NUM> is disposed upstream of the damper <NUM>. It is hereby noted that "upstream" indicates a step performed earlier in a processing process. To be specific, the first filter <NUM> is disposed between the tank <NUM> and the damper <NUM>, and the slurry passes through the damper <NUM> after being filtered by the first filter <NUM>. When the damper <NUM> is disposed between the valve <NUM> and the coating head <NUM>, the first filter <NUM> is disposed upstream of the damper <NUM>. To be specific, the first filter <NUM> is disposed between the valve <NUM> and the damper <NUM>, and the slurry passes through the damper <NUM> after being filtered by the first filter <NUM>. This ensures that the slurry pressure fluctuations caused by the slurry passing through the first filter <NUM> can be balanced by the damper <NUM>.

In some embodiments, the coating system <NUM> further includes a second filter <NUM> and a delivery system <NUM>. The delivery system <NUM> is configured to feed the slurry to the tank <NUM>. The second filter <NUM> is disposed between the delivery system <NUM> and the tank <NUM>, and configured to perform filtering between the delivery system <NUM> and the tank <NUM>. The second filter <NUM> filters larger particles than the first filter <NUM>. The first filter <NUM> is a three-element filter, and the second filter <NUM> is a rotary filter. Definitely, depending on actual needs, the first filter <NUM> and the second filter <NUM> may be of the same type. For example, both the first filter <NUM> and the second filter <NUM> are three-element filters, or both the first filter <NUM> and the second filter <NUM> are rotary filters.

In some embodiments, the coating system <NUM> is further equipped with a flowmeter <NUM> and a pressure sensor <NUM>. The flowmeter <NUM> and the pressure sensor <NUM> can detect the slurry flow and the cavity pressure of the die in real time during the coating, and feed back a detection result to make an adjustment. The flowmeter <NUM> is disposed between the feeding pump <NUM> and the valve <NUM>. The flowmeter <NUM> may be integrated with the coating measurement system <NUM> such as a β/X-ray system to implement a closed-loop control system, thereby making the coating weight more uniform and improving the consistency of the coating weight. The pressure sensor <NUM> is disposed between the tank <NUM> and a back-feed port <NUM> (to be described later) of the valve <NUM>.

As shown in <FIG>, <FIG> is a schematic diagram of the coating head <NUM> from a first viewing angle; <FIG> is a schematic diagram of the coating head <NUM> from a second viewing angle; and <FIG> is a sectional view of the coating head <NUM>.

The number of dispensing cavities <NUM> is two. The coating head <NUM> includes a lower die <NUM>, a middle die <NUM>, and an upper die <NUM>. One dispensing cavity <NUM> is formed between a lower surface of the upper die <NUM> and an upper surface of the middle die <NUM>, and defined as a first dispensing cavity 11a; and another dispensing cavity <NUM> is formed between a lower surface of the middle die <NUM> and an upper surface of the lower die <NUM>, and defined as a second dispensing cavity 11b. The coating head <NUM> includes a lower die <NUM>, a middle die <NUM>, and an upper die <NUM>. After being combined, the middle die <NUM> and the upper die <NUM> form a dispensing cavity, and the middle die <NUM> and the lower die <NUM> form another dispensing cavity <NUM>. In this way, it is convenient to disassemble the coating head <NUM> for cleaning the interior of the dispensing cavity <NUM> and replacing parts in the dispensing cavity <NUM>.

A first in-feed port <NUM> that communicates with the first dispensing cavity 11a is disposed on the upper die <NUM>. The feeding apparatus <NUM> feeds the slurry to the first dispensing cavity 11a from the first in-feed port <NUM>. A second in-feed port <NUM> that communicates with the second dispensing cavity 11b is disposed on the lower die <NUM>. The feeding apparatus <NUM> feeds the slurry to the second dispensing cavity 11b from the second in-feed port <NUM>.

The dispensing cavity <NUM> between the upper die <NUM> and the middle die <NUM> is formed between the lower surface of the upper die <NUM> and the upper surface of the middle die <NUM>. The dispensing cavity <NUM> between the middle die <NUM> and the lower die <NUM> is formed between the lower surface of the middle die <NUM> and the upper surface of the lower die <NUM>.

The first dispensing cavity 11a includes a first groove <NUM> and a second groove <NUM>. The second groove <NUM> is closer to the coating opening than the first groove <NUM>. The first groove <NUM> and the second groove <NUM> are spaced out in a first direction. A first slow flow region (not shown in the drawing) is formed between the first groove <NUM> and the second groove <NUM>. The width of the first groove <NUM> is greater than the width of the second groove <NUM>. The first in-feed port <NUM> is in direct communication with the first groove <NUM>. The slurry fed from the first in-feed port <NUM> passes through the first groove <NUM>, the first slow flow region, and the second groove <NUM> in sequence, and is finally extruded through the coating opening. From the first in-feed port <NUM> to the coating opening, the flow speed of the slurry declines gradually. The second groove <NUM> serves to reduce the flow speed of the incoming slurry, and avoid pressure distribution nonuniformity of the slurry fed from the first in-feed port <NUM>, where the nonuniformity is caused by loss of the flow pressure of the slurry in the first dispensing cavity 11a. In this way, the uniformity of the slurry flow is improved.

The first groove <NUM> is disposed on the lower surface of the upper die <NUM>, and the second groove <NUM> is disposed on the upper surface of the middle die <NUM>, thereby not only ensuring the structural strength of the middle die <NUM>, but also compensating for slurry pressure fluctuations and inferior flow steadiness caused by the weight of the slurry itself in a flowing process. Both the first groove <NUM> and the second groove <NUM> are arc grooves. When the slurry enters the first groove <NUM> and the second groove <NUM>, the slurry can be prevented from acting vertically on walls of the first groove <NUM> and the second groove <NUM>, thereby reducing the impact caused by the walls of the first groove <NUM> and the second groove <NUM> onto the slurry, and in turn, reducing the flow speed and pressure fluctuations of the slurry in the first groove <NUM> and the second groove <NUM>. In some embodiments, the first groove <NUM> and the second groove <NUM> may be grooves of other shapes.

In some embodiments, the first groove <NUM> and the second groove <NUM> may be both disposed on the upper surface of the middle die <NUM> or both disposed on the lower surface of the upper die <NUM>.

In some embodiments, the first dispensing cavity 11a may include just the first groove <NUM> or include just the second groove <NUM>.

In some embodiments, the first groove <NUM> is disposed on the lower surface of the upper die <NUM>, and the second groove <NUM> is disposed on the upper surface of the middle die <NUM>. The width of the first groove <NUM> is the same as the width of the second groove <NUM>. The first groove <NUM> and the second groove <NUM> are disposed opposite to each other to form an annular first dispensing cavity 11a.

The second dispensing cavity 11b includes a third groove <NUM> and a fourth groove <NUM>. The fourth groove <NUM> is closer to the coating opening than the third groove <NUM>. The third groove <NUM> and the fourth groove <NUM> are spaced out in the first direction. A second slow flow region (not shown in the drawing) is formed between the third groove <NUM> and the fourth groove <NUM>. The width of the third groove <NUM> is greater than the width of the fourth groove <NUM>. The second in-feed port <NUM> is in direct communication with the third groove <NUM>. The slurry fed from the second in-feed port <NUM> passes through the third groove <NUM>, the second slow flow region, and the third groove <NUM> in sequence, and is finally extruded through the coating opening. From the second in-feed port <NUM> to the coating opening, the flow speed of the slurry declines gradually. The fourth groove <NUM> serves to reduce the flow speed of the incoming slurry, and avoid pressure distribution nonuniformity of the slurry fed from the second in-feed port <NUM>, where the nonuniformity is caused by loss of the flow pressure of the slurry in the second dispensing cavity 11b. In this way, the uniformity of the slurry flow is improved. Both the third groove <NUM> and the fourth groove <NUM> are arc grooves. When the slurry enters the third groove <NUM> and the fourth groove <NUM>, the slurry can be prevented from acting vertically on walls of the third groove <NUM> and the fourth groove <NUM>, thereby reducing the impact caused by the walls of the third groove <NUM> and the fourth groove <NUM> onto the slurry, and in turn, reducing the flow speed and pressure fluctuations of the slurry in the third groove <NUM> and the fourth groove <NUM>. In some embodiments, the third groove <NUM> and the fourth groove <NUM> may be grooves of other shapes.

In this embodiment, the third groove <NUM> and the fourth groove <NUM> are disposed on the upper surface of the lower die <NUM>, thereby ensuring the structural strength of the middle die <NUM>.

In some embodiments, the third groove <NUM> and the fourth groove <NUM> may be both disposed on the lower surface of the middle die <NUM>, or the third groove <NUM> and the fourth groove <NUM> may be disposed on the upper surface of the lower die <NUM> and the lower surface of the middle die <NUM> respectively.

The second groove <NUM> is disposed on the upper surface of the middle die <NUM>, thereby not only ensuring the structural strength of the middle die <NUM>, but also compensating for slurry pressure fluctuations and inferior flow steadiness caused by the weight of the slurry itself in a flowing process.

In some embodiments, the second dispensing cavity 11b may include just the third groove <NUM> or include just the fourth groove <NUM>.

In some embodiments, the third groove <NUM> is disposed on the upper surface of the lower die <NUM>, and the fourth groove <NUM> is disposed on the lower surface of the middle die <NUM>. The width of the third groove <NUM> is the same as the width of the fourth groove <NUM>. The third groove <NUM> and the fourth groove <NUM> are disposed opposite to each other to form an annular second dispensing cavity 11b.

To expel the air in the two dispensing cavities <NUM>, a first exhaust port <NUM> and a second exhaust port <NUM> are disposed on the coating head <NUM>. The first exhaust port <NUM> is disposed on the upper die <NUM>, and communicates with the first dispensing cavity 11a. The second exhaust port <NUM> is disposed on the middle die <NUM>, and communicates with the second dispensing cavity 11b. In some embodiments, an auxiliary exhaust port <NUM> is further disposed on the upper die <NUM>. To increase the quality and efficiency of exhausting, two first exhaust ports <NUM> are disposed. The two first exhaust ports <NUM> are spaced out on the upper die <NUM> in a coating width direction D of the coating opening. Two second exhaust ports <NUM> are disposed. The two second exhaust ports <NUM> are spaced out on the lower die <NUM> in the coating width direction D of the coating opening.

In some embodiments, the coating head <NUM> further includes two spacers <NUM>. The two spacers <NUM> are disposed between the upper die <NUM> and the middle die <NUM>, and between the middle die <NUM> and the lower die <NUM>, respectively. The coating opening is disposed at the spacer <NUM>. The two spacers <NUM> are mounted on the lower die <NUM> and the middle die <NUM> respectively through a pressure plate <NUM>. The pressure plate <NUM> is configured to support the spacer <NUM> and prevent leakage of the slurry at the spacer <NUM>. The thickness of the spacer <NUM> can affect the coating thickness at the coating opening, and in turn, affect the coating weight. The coating weight can be adjusted by disposing spacers <NUM> of different thicknesses between the upper die <NUM> and the middle die <NUM>, and between the middle die <NUM> and the lower die <NUM>, respectively.

In some embodiments, the two spacers <NUM> may be mounted on the upper die <NUM> and the middle die <NUM> respectively.

In some embodiments, the coating head <NUM> is an integral structure. Therefore, the coating head <NUM> may be disposed without the spacer <NUM>, and the size of the coating opening is formed by machining.

In some embodiments, the upper die <NUM> is pivotally connected to the middle die <NUM>, and the middle die <NUM> is pivotally connected to the lower die <NUM>, so that all components of the coating head <NUM> are always connected together, and it is ensured that the relative position between the lower die <NUM>, the middle die <NUM>, and the upper die <NUM> is fixed. In clamping the lower die <NUM> to the middle die <NUM> or clamping the middle die <NUM> to the upper die <NUM>, the two dies can be clamped together accurately without a need to recalibrate the positions of the dies. The upper die <NUM> is pivotally connected to the middle die <NUM> by a first hinge <NUM>, and the middle die <NUM> is pivotally connected to the lower die <NUM> by a second hinge <NUM>.

The coating head <NUM> further includes a first die-clamping piece <NUM> and a second die-clamping piece <NUM>. The first die-clamping piece <NUM> is configured to fix the upper die <NUM> and the middle die <NUM> when clamping the upper die <NUM> to the middle die <NUM>. The second die-clamping piece <NUM> is configured to fix the middle die <NUM> and the lower die <NUM> when clamping the middle die <NUM> to the lower die <NUM>. When the upper die <NUM> and the middle die <NUM> are clamped together, the first die-clamping piece <NUM> is connected to the upper die <NUM> and the middle die <NUM> concurrently to keep firm connection between the upper die <NUM> and the middle die <NUM>. When the lower die <NUM> and the middle die <NUM> are clamped together, the second die-clamping piece <NUM> is connected to the lower die <NUM> and the middle die <NUM> concurrently to keep firm connection between the lower die <NUM> and the middle die <NUM>. The first die-clamping piece <NUM> and the second die-clamping piece <NUM> can implement firm connection between the upper die <NUM> and the middle die <NUM>, and between the middle die <NUM> and the lower die <NUM>, respectively, so as to ensure stability of pressure and flow speed of the slurry in the two dispensing cavities <NUM>, and in turn, improve the coating quality. The first die-clamping piece <NUM> and the second die-clamping piece <NUM> may be connecting pieces such as screws and bolts.

To further keep firm connection between the upper die <NUM>, the middle die <NUM>, and the lower die <NUM> in a die-clamping state, the coating head <NUM> further includes a fixing back plate <NUM>. One end of the fixing back plate <NUM> is detachably connected to the middle die <NUM>, and the other end of the fixing back plate <NUM> is detachably connected to the lower die <NUM>.

The coating head <NUM> further includes a flip lever <NUM>. There may be one flip lever <NUM> mounted on the middle die <NUM>. Alternatively, there may be a plurality of flip levers <NUM>. For example, there are two flip levers <NUM>. The two flip levers <NUM> are mounted on the upper die <NUM> and the middle die <NUM> respectively, or the two flip levers <NUM> are mounted on the middle die <NUM> and the lower die <NUM> respectively, or the two flip levers <NUM> are mounted on the upper die <NUM> and the lower die <NUM> respectively. For another example, there are three flip levers <NUM>. The three flip levers <NUM> are mounted on the upper die <NUM>, the middle die <NUM>, and the lower die <NUM> respectively.

When cleaning the first dispensing cavity 11a or replacing the spacer <NUM> between the upper die <NUM> and the middle die <NUM>, the operator detaches the first die-clamping piece <NUM>, and holds the flip lever <NUM> in hand to open the upper die <NUM> around a rotation axis of the first hinge <NUM>, so as to clean the first dispensing cavity 11a or replace the spacer <NUM>. When cleaning the second dispensing cavity 11b or replacing the spacer <NUM> between the lower die <NUM> and the middle die <NUM>, the operator detaches the second die-clamping piece <NUM> and the fixing back plate <NUM>, and holds the flip lever <NUM> in hand to open the middle die <NUM> around a rotation axis of the second hinge <NUM>, so as to clean the second dispensing cavity 11b or replace the spacer <NUM>.

In some embodiments, the coating head <NUM> further includes a tuning mechanism <NUM>. The tuning mechanism <NUM> is configured to adjust the coating flow at the coating opening. The tuning mechanism <NUM> is a micrometer tuning mechanism <NUM>. The micrometer tuning mechanism <NUM> is a tuning mechanism <NUM> with a tuning precision as high as the precision of a micrometer, so as to improve the tuning precision. The tuning mechanism <NUM> is mounted on the upper die <NUM> through a fixing plate <NUM> and a fastening screw <NUM>. There are a plurality of tuning mechanisms <NUM>. The plurality of tuning mechanisms <NUM> are spaced out along a coating width direction D of the coating opening, so as to adjust the coating flow in a part or all of the region in the width direction.

The coating head <NUM> further includes a tuning push-pull rod <NUM> to adjust the weight of the lower die <NUM>. The push-pull rod is threadedly connected to a U-shaped groove (not shown in the drawing) that is of the lower die <NUM> and that is close to the back side of the lip. A push-pull torque is applied to adjust the opening size of the lip. In practice, the tuning mechanism <NUM> and the tuning push-pull rod <NUM> adjust the opening size of the lip by adjusting an area of the coating opening of the dispensing cavity <NUM>, where the area is blocked by the tuning mechanism <NUM> and the tuning push-pull rod <NUM>. When the coating opening area blocked by the tuning mechanism <NUM> and the tuning push-pull rod <NUM> is larger, the opening size of the lip is smaller, and the coating weight is smaller. When the coating opening area blocked by the tuning mechanism <NUM> and the tuning push-pull rod <NUM> is smaller, the opening size of the lip is larger, and the coating weight is greater.

In some embodiments, the coating head <NUM> may be an integral structure instead. The dispensing cavity <NUM> and the coating opening are formed by machining the coating head <NUM>.

In some embodiments, the coating system <NUM> further includes a back roller <NUM>. The substrate <NUM> is wound around the back roller <NUM>. The back roller <NUM> is configured to drive the substrate <NUM>. When the back roller <NUM> rotates, friction between the back roller <NUM> and the substrate <NUM> can drive the substrate <NUM> to move along an extension direction of the substrate <NUM>.

An out-feed direction of each coating opening coincides with an extension direction of a diameter of the back roller <NUM>. The out-feed direction of the coating opening is along a diameter direction of the back roller <NUM>, thereby preventing the lip of the coating head <NUM> from scraping the slurry.

In some embodiments, an out-feed direction of the coating opening of one dispensing cavity <NUM> among all the dispensing cavities <NUM> is arranged horizontally. The horizontal direction C is perpendicular to the vertical direction. The out-feed direction of one of the coating openings of the coating head <NUM> is arranged horizontally, thereby preventing the lip of the coating head <NUM> from scraping the slurry. In addition, the coating head <NUM> vibrates up and down during a coating operation. When the coating head <NUM> vibrates up and down, the horizontally arranged coating opening changes positions merely in the vertical direction, but a horizontal distance between the coating opening and a center of the back roller <NUM> changes scarcely. The impact thereby caused on the coating thickness of the slurry out of the coating opening is small, thereby helping to ensure coating quality.

When the back roller <NUM> drives the substrate <NUM> to move at a high speed, air is brought to the coating opening to cause instability of the airflow at the coating opening. The slurry extruded from an nozzle of the coating opening is very thin. If an unstable airflow keeps perturbing the coating opening, affinity between the slurry and the substrate <NUM> will decline, bubbles and foil scraps will occur in the slurry applied on the substrate <NUM>, and the coating effect will be inferior. In addition, the uniformity of the coating will be impaired by the non-uniform air retained at the coating opening. This phenomenon is severer especially when the slurry viscosity and the solid content are relatively low.

In view of this, in some embodiments, the coating system <NUM> further includes an adsorption apparatus <NUM> (referring to <FIG>). The adsorption apparatus <NUM> is configured to keep the air pressure stable at the coating opening. The adsorption device <NUM> is a vacuum apparatus. The adsorption apparatus <NUM> includes a vacuum pump. A suction port of the vacuum pump is located upstream of the coating head <NUM>. The suction port of the adsorption apparatus <NUM> takes in air upstream of the coating head, and can keep the air pressure stable at the coating opening from upstream of the coating head <NUM>, so as to prevent the slurry at the coating opening from being affected by air flow fluctuations, increase affinity between the slurry and the substrate <NUM>, increase coating uniformity, and in turn, improve the coating quality. It is hereby noted that "upstream" means an earlier step of a processing process, and "a step performed upstream of the coating head <NUM>" means a step performed before the coating step.

In some embodiments, an adhesive dispensing valve <NUM> is disposed on the coating head <NUM>. The adhesive dispensing valve <NUM> is mounted on the lower die <NUM>. The adhesive dispensing valve <NUM> is configured to dispense an insulation adhesive at tabs of an electrode plate.

In some embodiments, referring to <FIG> is a schematic structural diagram of a valve <NUM>. The valve <NUM> includes a valve body <NUM>, a first valve core <NUM>, a second valve core <NUM>, a first drive component <NUM>, and a second drive component <NUM>. The valve body <NUM> includes an in-feed port <NUM>, a back-feed port <NUM>, and an out-feed port <NUM>. The out-feed port <NUM> communicates with the dispensing cavity <NUM>, the in-feed port <NUM> communicates with an outlet of the feeding pump <NUM>, and the back-feed port <NUM> communicates with the tank <NUM>. The first drive component <NUM> is configured to drive the first valve core <NUM> to move in the valve body <NUM>, so as to implement communication or disconnection between the in-feed port <NUM> and the out-feed port <NUM>. The second drive component <NUM> is configured to drive the second valve core <NUM> to move in the valve body <NUM>, so as to implement communication or disconnection between the out-feed port <NUM> and the back-feed port <NUM>.

Both the first drive component <NUM> and the second drive component <NUM> are linear driving mechanisms, such as air cylinders, and electric linear actuators. The first drive component <NUM> is fixedly mounted on the valve body <NUM>. The first valve core <NUM> is fixed onto an output end of the first drive component <NUM>. The second drive component <NUM> is fixedly mounted onto an output end of the second drive component <NUM>. To implement coating, the first drive component <NUM> drives the first valve core <NUM> to move upward, so that the in-feed port <NUM> communicates with the out-feed port <NUM>, and therefore, the feeding pump <NUM> can pump the slurry into the dispensing cavity <NUM>. The second drive component <NUM> drives the second valve core <NUM> to move downward, so that the out-feed port <NUM> is disconnected from the back-feed port <NUM>, and therefore, the slurry in the dispensing cavity <NUM> is unable to flow back to the tank <NUM>. When no coating is required, the first drive component <NUM> drives the first valve core <NUM> to move downward, so that the in-feed port <NUM> is disconnected from the out-feed port <NUM>, and therefore, the slurry is unable to enter the dispensing cavity <NUM> from the in-feed port. The second drive component <NUM> drives the second valve core <NUM> to move upward, so that the out-feed port <NUM> communicates with the back-feed port <NUM>, and therefore, the slurry in the dispensing cavity <NUM> flows back to the tank <NUM>. When the in-feed port <NUM> is in communication with the out-feed port <NUM>, before the movement of the first valve core <NUM> causes the slurry to flow into the dispensing cavity <NUM>, the first valve core <NUM> does not directly act on the slurry, and will not affect the slurry pressure. When the back-feed port <NUM> is in communication with the out-feed port <NUM>, before the movement of the second valve core <NUM> causes the slurry to flow into the tank <NUM>, the second valve core <NUM> does not directly act on the slurry, and will not affect the slurry pressure, thereby improving the coating quality.

The backflow of the slurry may be implemented by virtue of flow characteristics of the slurry itself, or may be implemented by a power apparatus similar to the feeding pump <NUM>. The valve <NUM> can feed the slurry to the coating head <NUM>, and can implement backflow of the slurry. When no coating is required, the slurry can flow back in time to prevent the slurry in the dispensing cavity <NUM> from affecting effects of clearance coating or local thin coating.

The valve <NUM> further includes a first sealing structure <NUM> and a second sealing structure <NUM>. The first sealing structure <NUM> is disposed between the valve body <NUM> and the output end of the first drive component <NUM>. The second sealing structure <NUM> is disposed between the valve body <NUM> and the output end of the second drive component <NUM>.

In some embodiments, the valve <NUM> may be an on-off valve capable of implementing communication or disconnection between the dispensing cavity <NUM> and the feeding apparatus <NUM> but not necessarily capable of backflow.

Claim 1:
A coating system (<NUM>), applied to coating a substrate to form an electrode plate, comprising:
a coating head (<NUM>), equipped with at least two dispensing cavities (<NUM>) independent of each other, wherein each dispensing cavity (<NUM>) comprises a coating opening;
a feeding apparatus (<NUM>), connected to the dispensing cavity (<NUM>), and configured to feed a slurry to the dispensing cavity (<NUM>); and
a valve (<NUM>), disposed between at least one dispensing cavity (<NUM>) and the feeding apparatus (<NUM>), and configured to implement communication or disconnection between a corresponding dispensing cavity (<NUM>) and the feeding apparatus (<NUM>);
wherein a number of the dispensing cavities (<NUM>) is two;
the coating head (<NUM>) comprises a lower die (<NUM>), a middle die (<NUM>), and an upper die (<NUM>); and
a first dispensing cavity (11a) is formed between a lower surface of the upper die (<NUM>) and an upper surface of the middle die (<NUM>), and a second dispensing cavity (11b) is formed between a lower surface of the middle die (<NUM>) and an upper surface of the lower die (<NUM>),
characterized in that the first dispensing cavity (11a) includes a first groove (<NUM>) and a second groove (<NUM>), wherein the second groove (<NUM>) is closer to the coating opening than the first groove (<NUM>), wherein the first groove (<NUM>) and the second groove (<NUM>) are spaced out in a first direction, wherein a first slow flow region is formed between the first groove (<NUM>) and the second groove (<NUM>), wherein the width of the first groove (<NUM>) is greater than the width of the second groove (<NUM>), wherein the feeding apparatus (<NUM>) feeds the slurry to the first dispensing cavity (11a) from a first in-feed port (<NUM>), and wherein the first in-feed port (<NUM>) is in direct communication with the first groove (<NUM>).