Coating die head and device

Abstract

The utility model provides a coating die head and device, the coating die head comprises a die head body and a spraying module, and the die head body is used for coating a current collector to form an active slurry layer; and the spraying module is arranged on the die head body and is used for spraying the current collector to form a functional layer positioned above or below the active slurry layer. According to the coating die head, the spraying module and the die head body are integrated, the die head body can coat the surface of the current collector to form an active slurry layer through one coating die head, the spraying module sprays the current collector to form a functional layer, the coating sequence of the spraying module and the die head body is controlled, and therefore the purpose that in the coating process, the active slurry layer is formed is achieved. And the functional layer and the active slurry layer are synchronously compounded at different positions. And an additional coating process is avoided, so that the efficiency of the coating process is greatly improved, and the production efficiency of the battery monomer is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular, to a coating die head and a device. Background Art

[0002] With the development of new energy technologies, batteries are increasingly widely used, such as in mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools.

[0003] The battery electrode is the main functional component of the battery. In the manufacturing process of existing battery electrodes, multiple coating processes are required. Coating devices are widely used in the precision coating industry, especially in the coating of battery electrodes. The coating device coats a specific functional glue, coating, ink, etc. on the surface of a rolled substrate through a coating die head, and after drying, it is cut into pieces or wound up, etc.

[0004] The coating die head usually consists of an upper die head, a lower die head, and a gasket sandwiched between them. A notch for the slurry to flow out is provided at the front end of the gasket. The upper die head and the lower die head, together with the gasket, enclose a coating slit. The slurry is extruded through the coating slit from the coating lip to the substrate on the coating roller to form an active slurry layer on the substrate.

[0005] In the processing of battery electrodes, different functional material layers need to be coated on the surface of the substrate of the electrode according to different functional requirements of the electrode, so as to prepare a composite electrode. Usually, after the active slurry layer is coated by the coating die head on one device, the functional material layer is continuously coated on the electrode coated with the active slurry layer by the coating die head of another device. This coating process increases the manufacturing process and results in low production efficiency. Summary of the Utility Model

[0006] The embodiments of the present application provide a coating die head and a device. The coating die head of the present application integrates a spraying module with the die head body. Through one coating die head, an active slurry layer can be formed on the surface of the current collector by the die head body, and a functional layer can be formed by spraying the current collector by the spraying module. By controlling the coating sequence of the spraying module and the die head body, during the coating process, the functional layer and the active slurry layer are synchronously compounded at different positions.

[0007] In a first aspect, the embodiments of the present application provide a coating die head, including: a die head body for coating an active slurry layer on a current collector; a spraying module disposed on the die head body for spraying a functional layer on or under the active slurry layer on the current collector.

[0008] In the above technical solution, the coating die integrates the spraying module and the die body. Through one coating die, an active slurry layer can be formed on the surface of the current collector by the die body, and a functional layer can be sprayed on the current collector by the spraying module. By controlling the coating sequence of the spraying module and the die body, the synchronous composite of the functional layer and the active slurry layer at different positions can be realized during the coating process. This avoids adding extra coating processes, greatly improves the efficiency of the coating process, and further improves the production efficiency of battery monomers.

[0009] In some embodiments, the spraying module is an electrospinning module. By combining the high-voltage electrospinning technology with the coating process in the battery field, through integrating the electrospinning module and the die body, an active slurry layer is coated on the surface of the current collector by the die body, and a functional medium with different functions is sprayed on the surface of the current collector by the spraying module. Utilizing the breakdown effect of the high-voltage electrostatic field on the functional medium, the functional medium is stretched after passing through the electrostatic field, and finally a non-woven functional layer is formed by spraying on the surface of the current collector. It can realize the combination of the active slurry layer coating process and the functional layer coating process with one coating die, and further realize the synchronous composite of the functional layer and the active slurry layer at different positions on the surface of the current collector during the coating process, reducing the extra coating process and improving the coating efficiency.

[0010] The spraying module adopts an electrospinning module. Since the functional medium is stretched longer under the action of the electrostatic field, the formed functional medium has a slender shape, so that a more stable non-woven state can be formed, the functional medium is less likely to break, and finally the thickness of the functional layer coated on the surface of the current collector is more uniform, which can further improve the coating quality.

[0011] In some embodiments, the spraying module includes a channel and a nozzle; the die body is provided with an installation groove, the channel is arranged in the installation groove, and the nozzle is arranged on the side of the channel close to the current collector. By setting an installation groove for installing the spraying module in the die body, the spraying module is embedded and installed in the installation groove of the die body. The embedded installation method saves more space and further improves the installation and integration stability of the spraying module in the die body.

[0012] In some embodiments, multiple spraying modules are provided, and the multiple spraying modules are arranged at intervals. Since multiple spraying modules are provided, each spraying module can split the functional medium to improve the uniformity of the functional medium and improve the consistency of the coating thickness of the functional medium on the surface of the current collector.

[0013] In some embodiments, the spraying module is a centrifugal electrospinning module. By rotating the centrifugal electrospinning module to generate centrifugal force, the functional medium is thrown out and forms a more stable and continuous fibrous shape under the action of the electrostatic field, so that the thickness of the functional layer coated on the surface of the current collector is more uniform.

[0014] In some embodiments, the die body includes: a first die, a second die, and a gasket disposed between the first die and the second die; the first die and / or the second die is provided with a jet module. By providing two dies, the jet module can be integrally installed with any one of the dies or both dies, enabling the lamination of a single-layer functional medium, a double-layer functional medium, and an active slurry layer, thereby achieving the coating of the composite electrode sheet.

[0015] In some embodiments, the die body includes: a first die, a second die, a third die, a first gasket disposed between the first die and the second die, and a second gasket disposed between the second die and the third die; at least one of the first die, the second die, and the third die is provided with a jet module. The die body composed of the first die, the second die, and the third die can not only achieve the coating of a three-layer functional medium, but also the coating of a single-layer functional medium and a double-layer functional medium, thereby realizing the lamination of a multi-layer functional medium and an active slurry layer, with a wider range of coating scenarios and more types of composite electrode sheets prepared.

[0016] In some embodiments, the die body is provided with a mounting member, and the jet module is disposed on the die body through the mounting member. The mounting member is independent of the exterior of the die body, and the integration of the die body and the jet module is achieved through the mounting member, reducing the installation difficulty and facilitating the disassembly and replacement of the jet module.

[0017] In a second aspect, an embodiment of the present application provides a coating device, including the coating die provided in any one of the embodiments of the first aspect, and a back roller for conveying the current collector; the back roller is disposed on one side of the coating die. During the process of the back roller rotating to drive the current collector to run, the coating die can continuously coat the active slurry and jet the functional medium onto the current collector to achieve the coating process of the composite electrode sheet, improving the continuity of the coating process of the coating device.

[0018] In some embodiments, the coating device further includes: a drying unit for drying the current collector wound around the back roller. By providing the drying unit, not only can the volatile substances generated when the coating die coats the active slurry layer and jets the functional layer be dried in a timely manner, but also the volatile substances generated by the active slurry layer and the functional layer formed on the surface of the current collector can be dried in a timely manner, keeping the coating process in a relatively dry environment all the time.

[0019] In some embodiments, the coating device further includes: an exhaust unit for collecting and processing the volatile gases generated during the coating process of the coating device. By providing the exhaust unit, not only can the volatile gases mixed in the volatile substances generated when the coating die coats the active slurry and sprays the functional medium be processed in a timely manner, but also the volatile gases mixed in the volatile substances generated by the active slurry layer and the functional layer formed on the surface of the current collector wound around the back roller can be collected and processed in a timely manner, so as to reduce the harm caused by the volatile gases to the human body and the pollution to the air. When the exhaust unit and the drying unit are provided simultaneously, not only can the effective and timely drying treatment of the volatile substances be achieved, but also the timely removal of the volatile gases can be realized, creating a suitable temperature and relatively dry environment for the coating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 Structural schematic diagram of a coating die provided by some embodiments of the present application;

[0022] Figure 2 Structural schematic diagram of a die body provided by some embodiments of the present application;

[0023] Figure 3 Structural schematic diagram of a die body provided by some other embodiments of the present application;

[0024] Figure 4 Top view of a spray module provided by some embodiments of the present application;

[0025] Figure 5 Top view of a spray module provided by some other embodiments of the present application;

[0026] Figure 6 Schematic diagram of coating a coating die and a current collector provided by some embodiments of the present application;

[0027] Figure 7 Structural schematic diagram of a coating device provided by some embodiments of the present application.

[0028] Reference numerals:

[0029] 100 - Coating device; 1 - Coating die head; 11 - Die head body; 111 - First die head; 112 - Second die head; 113 - Gasket; 114 - Discharge port; 1141 - First discharge port; 1142 - Second discharge port; 115 - Confluence chamber; 116 - Third die head; 117 - First gasket; 118 - Second gasket; 12 - Injection module; 121 - Channel; 122 - Nozzle; 2 - Current collector; 3 - Back roller; 4 - Drying unit; 5 - Exhaust unit; 6 - Feeding device; 7 - Conveying drive device; 71 - Unwinding mechanism; 72 - Rewinding mechanism. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments, and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above accompanying drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above accompanying drawings are used to distinguish different objects, rather than to describe a specific order or primary-secondary relationship.

[0032] Referring to "embodiments" in this application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0033] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", and "attached to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] The term "and / or" in this application merely describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this application, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0035] In the embodiments of this application, the same reference numerals represent the same components. For the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, and other dimensions of various components shown in the drawings in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0036] The term "a plurality of" as used in this application refers to two or more (including two).

[0037] In the embodiments of this application, coating is to cover a thin layer of coating slurry in liquid or powder form on the surface of objects such as substrates and electrode sheets. Coating is an indispensable step in the manufacturing process of battery cells.

[0038] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium-metal batteries, sodium-metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0039] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive and negative electrodes and at the same time allow active ions to pass through.

[0040] In some embodiments, the positive electrode can be a positive electrode sheet, and the positive electrode sheet can include a positive electrode current collector and a positive electrode coating slurry disposed on at least one surface of the positive electrode current collector.

[0041] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode coating slurry is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0042] As an example, the positive electrode current collector can be made of a metal foil or plate. For example, as the metal foil or plate, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used.

[0043] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector and a negative electrode coating slurry disposed on at least one surface of the negative electrode current collector.

[0044] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode coating slurry is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0045] As an example, the negative electrode current collector can be made of porous metal. For example, the porous metal can be porous nickel, porous copper, porous aluminum, porous alloy, etc.

[0046] The coating slurry includes an active slurry and a functional medium. The active slurry can be a non-Newtonian fluid with good stability, viscosity, fluidity, and shear thinning phenomenon.

[0047] In some embodiments, the various ingredients used to form the active slurry can be mixed in a certain proportion to obtain a mixed slurry, and the temperature of the mixed slurry is made to conform to a preset temperature range to form the active slurry. The active slurry can be a positive electrode active slurry commonly used in the art, or a negative electrode active slurry commonly used in the art.

[0048] As an example, the positive electrode active slurry can include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the battery positive electrode active slurry can also be used. These positive electrode active slurries can be used alone or in combination of two or more. Among them, examples of the lithium-containing phosphates can include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, etc. Examples of the lithium transition metal oxides can include, but are not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (It can also be abbreviated as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (It can also be abbreviated as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (It can also be abbreviated as NCM 811 )、lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and at least one of its modified compounds, etc.

[0049] As an example, the negative electrode active paste may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active paste of the battery can also be used. These negative electrode active pastes can be used alone or in combination of two or more.

[0050] The functional medium refers to a liquid medium that can coat functional layers including but not limited to insulating isolation layers, mechanical strength increasing layers, lithium supplementing layers, etc. on any one or both of the two opposite surfaces of the positive electrode current collector or the negative electrode current collector. As an example, the functional medium includes but is not limited to polyethylene (Polyethylene, which can also be abbreviated as PE), polypropylene (Polypropylene, which can also be abbreviated as PP), carbon fiber (Carbon Fiber, which can also be abbreviated as CF), lithium supplementing agent (such as Li 2 NiO 2 (LNO), Li 5 FeO 4 (LFO), Li 2 O), plasticizer (Plasticizer), binder, etc.

[0051] During the processing of battery components, it is necessary to coat at least one of the active slurry and the functional medium on at least one surface of the current collector according to different functional requirements of the battery. To form a composite electrode, usually one coating die is used to coat the active slurry on at least one surface of the current collector, and then another coating die is used to continue coating the functional medium on the surface of the current collector coated with the active slurry to form a functional layer. This coating process increases the manufacturing process of the battery components and affects the production efficiency of the battery cells.

[0052] To solve the problem of low production efficiency of battery cells caused by the cumbersome coating process, in the coating process of battery cells, in this application, the spraying module is integrated with the die body. The die body is used to coat the active slurry, and the spraying module is used to spray the functional medium, so that the active slurry layer and the functional layer can be coated synchronously, reducing the steps of the coating process during the production of battery cells, improving the efficiency of the coating process, and improving the production efficiency of battery cells.

[0053] The coating die 1 provided by the embodiments of this application can be applied not only in the production process of battery electrodes, but also in the production processes of electronic materials such as printed circuit boards and electronic chips.

[0054] Please refer to Figure 1 , the embodiments of this application provide a coating die 1, including: a die body 11 and a spraying module 12. The die body 11 is used to coat the current collector to form an active slurry layer; the spraying module 12 is arranged on the die body 11, and the spraying module 12 is used to spray the current collector to form a functional layer above or below the active slurry layer.

[0055] The structure of the coating die 1 in this embodiment integrates the spraying module 12 with the die body 11. Through one coating die 1, it can be realized that the die body 11 coats the current collector surface to form an active slurry layer, and the spraying module 12 sprays the current collector to form a functional layer, so as to realize the synchronous compounding of the functional layer and the active slurry layer on the current collector during the coating process, reducing the coating process steps of the composite electrode, greatly improving the efficiency of the coating process, and improving the production efficiency of battery cells. It should be noted that the order of coating the active slurry layer and the functional layer on the current collector can be selected according to the coating process requirements and the production requirements of battery components.

[0056] In some embodiments, the coating die 1 can be coated by one of the slit extrusion coating technology, blade coating technology, comma roll blade coating technology, etc. The working principle of the slit extrusion coating technology is that the active slurry is extruded and ejected along the slit of the coating die under a certain pressure and flow rate and then transferred to the current collector. The working principle of the blade coating technology is that when the current collector passes between the coating roll and the blade, the blade scrapes off the excess slurry and returns it, and a uniform coating is formed on the surface of the current collector. The working principle of the comma roll blade coating technology is that the amount of slurry transfer is adjusted through the gap of the comma blade, and the slurry is transferred to the current collector by the rotation of the back roll and the coating roll. The slit extrusion coating technology has the advantages of fast coating speed, high precision, and uniform wet thickness.

[0057] As an example, in this embodiment, the coating die 1 is described using the slit extrusion coating technology.

[0058] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of the die body 11 provided in some embodiments of the present application. The die body 11 includes: a first die 111, a second die 112, and a gasket 113 disposed between the first die 111 and the second die 112. Among them, the gasket 113 is used to separate the first die 111 and the second die 112 to form a slit therebetween, and this slit serves as the discharge port 114 for the active slurry.

[0059] In some embodiments, the first die 111 is an upper die, the second die 112 is a lower die, and the first die 111 is disposed opposite above the second die 112. A cavity is formed in the second die 112, and the active slurry enters the cavity from the feed port of the feeding device. The feed port can be connected to the second die 112. The gasket 113 is disposed at the front end close to the current collector. The first die 111 and the second die 112 and the gasket 113 enclose a coating slit, and the active slurry is extruded to the surface of the current collector through the coating slit by the lips provided on the first die 111 and the second die 112, and an active slurry layer is formed by coating on the surface of the current collector. The second die 112 may be provided with a confluence cavity 115, and the confluence cavity 115 is recessed from the surface of the second die 112 facing the first die 111, and the confluence cavity 115 is communicated with the discharge port 114 from which the active slurry flows out.

[0060] In some other embodiments, the first die head 111 is a lower die head, the second die head 112 is an upper die head, and the second die head 112 is disposed opposite above the first die head 111. A cavity is formed in the first die head 111, and the active slurry enters the cavity from the feed port of the feeding device. The feed port can be connected to the first die head 111. The gasket 113 is disposed near the front end of the current collector. The first die head 111 and the second die head 112 and the gasket 113 enclose a coating slit, and the active slurry is extruded onto the surface of the current collector through the coating slit by the lips provided on the first die head 111 and the second die head 112, and an active slurry layer is formed by coating on the surface of the current collector. The first die head 111 may be provided with a confluence cavity 115. The confluence cavity 115 is recessed from the surface of the first die head 111 facing the second die head 112, and the confluence cavity 115 is used to communicate with the discharge port 114 from which the active slurry flows out.

[0061] In the above embodiments of the present application, the setting of the confluence cavity 115 can play a role in buffering and pressure equalization, so that the active slurry flows out of the discharge port 114 uniformly, and the consistency of the coating thickness of the active slurry on the surface of the current collector can be improved. The first die head 111 and the second die head 112 can be connected by means of fastening, snap connection or welding.

[0062] The first die head 111 and / or the second die head 112 is provided with a spraying module 12. In some embodiments, only the first die head 111 is provided with the spraying module 12; in some other embodiments, only the second die head 112 is provided with the spraying module 12; in some other embodiments, the first die head 111 and the second die head 112 can be provided with the spraying module 12 at the same time.

[0063] By providing two die heads, the spraying module 12 can be integrally installed with any one of the die heads or both die heads, and the composite of a single-layer functional medium, a double-layer functional medium and the active slurry layer can be realized, so as to realize the coating of the composite electrode sheet.

[0064] As an example, when only one functional layer needs to be coated on the surface of the current collector, the spraying module 12 can be provided on the first die head 111, or the spraying module 12 can be provided on the second die head 112.

[0065] As another example, when two functional layers need to be coated on the surface of the current collector, one way is to perform the injection operation of the functional medium twice through an injection module 12. Another way is to set two injection modules 12 on the die head body 11 to respectively perform the injection operation of the functional medium. At this time, the injection modules 12 can be respectively set on the first die head 111 and the second die head 112. By respectively setting the injection modules 12 on the first die head 111 and the second die head 112, each injection module 12 is used to inject different functional media, so as to coat two different functional media on the surface of the current collector, and it is not easy to cause the problem that the functional media are mixed in the injection module 12, resulting in poor final coating quality.

[0066] Therefore, according to the requirements of the coating process, the specific setting position of the injection module 12 on the die head body 11 can be correspondingly selected. Then, by controlling the injection module 12 to inject the functional medium onto the surface of the current collector and controlling the die head body 11 to coat the active slurry onto the surface of the current collector, a composite material layer composed of an active slurry layer and a functional layer is constructed on the surface of the current collector, realizing the coating of the composite electrode.

[0067] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of the die head body 11 provided in some other embodiments of the present application. The die head body 11 includes: a first die head 111, a second die head 112, a third die head 116, a first gasket 117 disposed between the first die head 111 and the second die head 112, and a second gasket 118 disposed between the second die head 112 and the third die head 116.

[0068] Among them, the first gasket 117 is used to separate the first die head 111 and the second die head 112 to form a slit therebetween, and this slit serves as the first discharge port 1141. The second gasket 118 is used to separate the second die head 112 and the third die head 116 and form a slit therebetween, and this slit serves as the second discharge port 1142.

[0069] In some embodiments, the first die head 111 is an upper die head, the second die head 112 is a middle die head, and the third die head 116 is a lower die head. Among them, cavities are formed on both the second die head 112 and the third die head 116. The active slurry enters the cavity of the second die head 112 through the feed port on the second die head 112 and is extruded to the first discharge port 1141 through the lips provided on the first die head 111 and the second die head 112. At the same time, the active slurry enters the cavity of the third die head 116 through the feed port on the third die head 116 and is extruded to the second discharge port 1142 through the lips provided on the second die head 112 and the third die head 116. The active slurry flowing out through the first discharge port 1141 and the second discharge port 1142 is coated on the surface of the current collector.

[0070] A manifold cavity 115 may be provided on both the second die head 112 and the third die head 116. Among them, the manifold cavity 115 on the second die head 112 is recessed from the surface of the second die head 112 facing the first die head 111. The manifold cavity 115 on the third die head 116 is recessed from the surface of the third die head 116 facing the second die head 112.

[0071] In the above embodiments of the present application, the setting of the manifold cavity 115 can play a role in buffering and pressure equalization, enabling the active slurry to flow out evenly from the first discharge port 1141 and the second discharge port 1142, and improving the consistency of the coating thickness. The first die head 111 and the second die head 112, and the second die head 112 and the third die head 116 can be connected by means such as fastening connection, snap connection or welding.

[0072] At least one of the first die head 111, the second die head 112, and the third die head 116 is provided with a spraying module 12. In some embodiments, only the first die head 111 is provided with the spraying module 12; or, only the second die head 112 is provided with the spraying module 12, or only the third die head 116 is provided with the spraying module 12.

[0073] In some other embodiments, the spraying module 12 is provided on the first die head 111 and the second die head 112 at the same time, and the third die head 116 is not provided with the spraying module 12, or the spraying module 12 is provided on the first die head 111 and the third die head 116 at the same time, and the second die head 112 is not provided with the spraying module 12, or the spraying module 12 is provided on the second die head 112 and the third die head 116 at the same time, and the first die head 111 is not provided with the spraying module 12.

[0074] In some other other embodiments, when it is necessary to coat three functional layers on the surface of the current collector, the spraying module 12 can be provided on the first die head 111, the second die head 112, and the third die head 116. By controlling the spraying module 12 corresponding to each die head to perform the spraying operation of the functional medium.

[0075] It can be understood that the use of Figure 3 the die body 11 composed of the first die head 111, the second die head 112, and the third die head 116 shown can not only achieve the coating of three-layer functional media, but also can achieve the coating of single-layer functional media and double-layer functional media, so as to realize the composite of multi-layer functional media and the active slurry layer. Its application coating scenarios are more extensive, and the types of composite electrodes prepared are more. Specifically, by controlling the spraying module 12 on the corresponding die head to perform the spraying operation of the functional medium.

[0076] Similarly, Figure 3 in each of the embodiments shown, according to the needs of the coating process, the specific setting position of the spraying module 12 on the die body 11 can be correspondingly selected. Then, by controlling the spraying module 12 to spray the functional medium onto the surface of the current collector, and by controlling the die body 11 to coat the active slurry onto the surface of the current collector, a composite material layer composed of an active slurry layer and a functional layer is constructed on the surface of the current collector, realizing the coating of the composite electrode.

[0077] As an example, in all the embodiments described above Figure 2 、 Figure 3 the spraying module 12 is an electrospinning module. The electrospinning module utilizes the high-voltage electrospinning technology. Its basic principle is to apply an electrostatic field between the spraying device and the receiving device, form a jet from the cone end of the spinning solution, and be stretched in the electric field, and finally form a non-woven functional layer on the receiving device.

[0078] It can be understood that the spraying device described here can be the spraying module 12 integrated on the die body 11, and the receiving device can be the current collector to be coated or the back roller for winding the current collector. The electrospinning solution is the aforementioned functional medium, including but not limited to the liquid media of functional layers such as the insulating isolation layer, the mechanical strength increasing layer, and the lithium supplement layer.

[0079] This application combines the high-voltage electrospinning technology with the coating process in the battery field. By integrating the electrospinning module with the die body 11, coating the active slurry layer onto the surface of the current collector through the die body 11, spraying the functional medium with different functions onto the surface of the current collector through the spraying module 12, and utilizing the breakdown effect of the high-voltage electrostatic field on the functional medium, the functional medium is stretched after being acted on by the electrostatic field, and finally a non-woven functional layer is sprayed and formed on the surface of the current collector. It realizes the combination of the active slurry layer coating process and the functional layer coating process with one coating die head 1, thus realizing the synchronous composite of the functional layer and the active slurry layer at different positions on the surface of the current collector during the coating process, reducing the additional coating process, and improving the coating efficiency.

[0080] Furthermore, the spraying module adopts an electrospinning module. Since the functional medium is stretched to a greater extent under the action of an electrostatic field, the formed functional medium has a slender shape, so that a more stable non-woven state can be formed, and the functional medium is less likely to break. Eventually, the thickness of the functional layer coated on the surface of the current collector is more uniform, which can further improve the coating quality.

[0081] In addition, the number of die head bodies 11 can be designed according to the needs of the coating process. Therefore, the electrospinning module can be integrated with a single-layer die head body 11 or a multi-layer die head body 11. When the electrospinning module is integrated with the multi-layer die head body 11, two or more active slurry layers can be coated through the multi-layer die head body 11, and one or more functional layers can be coated through the electrospinning module. Finally, the synchronous composite of the multi-layer functional layer and the multi-layer active slurry layer can be used to prepare the composite electrode sheet.

[0082] As some other examples, the spraying module 12 can also be a centrifugal electrospinning module. The centrifugal electrospinning module uses centrifugal spinning technology. Its basic principle is to use the centrifugal force generated by high-speed rotation to eject the functional medium solution from the spinneret holes, and then stretch it into fibers under the action of centrifugal force. Under the action of the high-voltage electrostatic field force, it assists the centrifugal force to overcome the surface tension of the functional medium, and further enables the functional medium molecules to self-organize into slender and continuous fiber filaments.

[0083] Specifically, the centrifugal electrospinning module can be integrated in the die head body 11, and a separate driving component is used to drive the centrifugal electrospinning module to rotate in the die head body 11 to generate centrifugal force, and the functional medium is ejected by the centrifugal force and forms continuous fibers under the action of the electrostatic field to be coated on the surface of the current collector.

[0084] Furthermore, please refer to Figure 4 , the spraying module 12 includes: a channel 121 and a nozzle 122; the die head body 11 is provided with a mounting groove (not shown), the channel 121 is arranged in the mounting groove, and the nozzle 122 is arranged on the side of the channel 121 close to the current collector.

[0085] In this embodiment, one mounting groove can be provided, and one spraying module 12 is correspondingly provided. The mounting groove is a structure of a hole or a groove dug inside the die head body 11. By embedding and installing the channel 121 into the mounting groove in the die head body 11, the nozzle 122 is installed outside the channel 121 and close to the current collector, which is convenient for the nozzle 122 to spray the functional medium onto the surface of the current collector.

[0086] In some embodiments, the nozzle 122 can be integrally formed with the channel 121, or the nozzle 122 can be welded to one end of the channel 121.

[0087] In some embodiments, an electronic valve may be provided on the nozzle 122, and the opening and closing of the nozzle 122 are achieved by controlling the opening and closing of the electronic valve, so as to control the injection module 12 to inject the functional medium onto the current collector to form a functional layer.

[0088] In some embodiments, taking Figure 2 as an example, one injection module 12 is installed in the first die head 111, and one injection module 12 is installed in the second die head 112. The specific installation method is as follows: an installation groove is provided in the first die head 111, and a corresponding channel 121 is embedded and installed into the installation groove in the first die head 111, and the nozzle 122 is installed on the side of the channel 121 close to the current collector. Similarly, an installation groove is provided in the second die head 112, and a corresponding channel 121 is embedded and installed into the installation groove in the second die head 112, and the nozzle 122 is installed on the side of the channel 121 close to the current collector.

[0089] In other embodiments, taking Figure 3 as an example, one injection module 12 is installed in the first die head 111, one injection module 12 is installed in the second die head 112, and one injection module 12 is installed in the third die head 116. The specific installation method is as follows: an installation groove is provided in the first die head 111, and a corresponding channel 121 is embedded and installed into the installation groove in the first die head 111, and the nozzle 122 is installed on the side of the channel 121 close to the current collector. An installation groove is provided in the second die head 112, and a corresponding channel 121 is embedded and installed into the installation groove in the second die head 112, and the nozzle 122 is installed on the side of the channel 121 close to the current collector. An installation groove is provided in the third die head 116, and a corresponding channel 121 is embedded and installed into the installation groove in the third die head 116, and the nozzle 122 is installed on the side of the channel 121 close to the current collector.

[0090] In the above embodiments of the present application, the embedding installation method is adopted, so that one injection module 12 is correspondingly provided in each die head of the die head body 11. The embedding installation method saves more space, and the installation of the injection module 12 is also more firm.

[0091] In some embodiments, please refer to Figure 5 , a plurality of injection modules 12 are provided, and the plurality of injection modules 12 are arranged at intervals. In this embodiment, the installation groove is a structure of a plurality of holes or grooves arranged at intervals dug in the die head body 11. Correspondingly, one injection module 12 is installed in each installation groove. Since a plurality of injection modules 12 are provided, each injection module 12 can divide the flow of the functional medium to improve the uniformity of the functional medium and improve the consistency of the coating thickness of the functional medium on the surface of the current collector.

[0092] To maximize the effect of the electrostatic field on the ejection module 12 while minimizing the influence of external interference factors, in some embodiments, a grating isolation cover can be installed outside the electrostatic field. The electrostatic field is placed in an isolated environment through the grating isolation cover, enabling the ejection module 12 to be under an electrostatic field with relatively fewer interference factors, which is more conducive to the electrostatic field exerting its effect. When the ejection module 12 ejects the functional medium, it can produce a functional layer in a better non-woven state, thereby making the coating thickness of the functional medium on the surface of the current collector more uniform.

[0093] Further, please refer to Figure 6 , Figure 6 for the schematic diagram of the coating die head 1 and the current collector 2 for coating. As an example, Figure 6 the structure of the die head body 11 of the coating die head 1 shown in Figure 2 can adopt the structure of two die heads including the first die head 111 and the second die head 112 shown in Figure 5 . The ejection module 12 can adopt the structure shown in

[0094] . Multiple ejection modules 12 are arranged at intervals. When the coating die head 1 coats the current collector 2, it is necessary to control the distance between the nozzle 122 on the coating die head 1 and the current collector 2 within an appropriate range. If the distance between the nozzle 122 and the current collector 2 is too far, the functional medium will be stretched more after being affected by the electrostatic field, and the shape of the formed functional medium will be longer and thinner, resulting in the fracture or unstable shape of the functional medium and making it difficult to spread on the surface of the current collector 2 to form a uniform functional layer. If the distance between the nozzle 122 and the current collector 2 is too small, the functional medium will easily form droplets of the functional medium on the surface of the current collector 2 after being affected by the electrostatic field, affecting the uniformity of the coating thickness on the surface of the current collector 2. In other words, the distance between the nozzle 122 and the current collector 2 determines the stretching degree and shape of the functional medium.

[0095] Therefore, in some embodiments, the solidification diameter of the functional layer formed by the nozzle 122 ejecting onto the current collector 2 is D, and the distance between the ejection end of the nozzle 122 and the current collector 2 is Q, where 0 ≤ Q ≤ 20 × 10 4 D, with the unit of mm.

[0096] In some embodiments, when the current collector 2 is conveyed by a belt conveyor mechanism and passes through the ejection module 12, and the current collector 2 and the nozzle 122 of the ejection module 12 are in a perpendicular state, at this time, the distance Q between the ejection end of the nozzle 122 and the current collector 2 can be expressed as the perpendicular straight-line distance from the ejection end of the nozzle 122 to the surface of the current collector 2.

[0097] In some other embodiments, when the current collector 2 is conveyed past the spraying module 12 by a rotation structure that is axisymmetric about the center of the cylinder, the current collector 2 is bent into a ring shape and wound around the rotation structure that is axisymmetric about the center of the cylinder. At this time, the distance Q between the spraying end of the nozzle 122 and the current collector 2 can be expressed as the shortest straight-line distance from the spraying end of the nozzle 122 to the surface of the current collector 2.

[0098] The spraying module 12 sprays a functional medium onto the current collector 2. After the functional medium is stretched under the action of an electrostatic field and solidifies from a liquid state on the surface of the current collector 2, a functional layer region is formed. This functional layer region has a circular structure. The diameter of the circular functional layer region is called the functional layer curing diameter D, and its unit is mm. Since the spraying end of the nozzle 122 is usually designed to be circular and the size is designed to be very small, the sprayed functional medium can be stretched under the action of the electrostatic field to form a non-woven filamentous circular spraying region.

[0099] The distance between the spraying end of the nozzle 122 and the surface of the current collector 2 is denoted as Q, where 0 ≤ Q ≤ 20×10 4 D. Based on the functional layer curing diameter D, the distance Q between the spraying end of the nozzle 122 and the surface of the current collector 2 can be calculated. As an example, Q can generally be taken between 0 and 10 mm.

[0100] In this embodiment, by controlling the functional layer curing diameter of the functional layer formed by the nozzle 122 spraying onto the current collector 2 and the distance between the spraying end of the nozzle 122 and the current collector 2 within a reasonable range, the functional medium can form a more stable non-woven state under the action of the electrostatic field, so that the thickness of the functional layer coated on the surface of the current collector 2 is more uniform.

[0101] In some embodiments, the functional layer curing diameter of the functional layer formed by the nozzle 122 spraying onto the current collector 2 is D, and the diameter of the spraying end of the nozzle 122 is M, where 100D ≤ M ≤ 2, and the unit is mm. As mentioned above, the size of the spraying end of the nozzle 122 is designed to be very small and should not be set too large, because if the diameter of the spraying end of the nozzle 122 is too large, after the functional medium is sprayed by the nozzle 122, it is not easy to form a non-woven state functional layer under the action of the electrostatic field.

[0102] Based on the functional layer curing diameter D, the range of the diameter M of the spraying end of the nozzle 122 can be selected. As an example, the diameter M of the nozzle 122 can be taken between 0 and 2 mm.

[0103] In this embodiment, by controlling the functional layer curing diameter of the functional layer formed by the nozzle 122 spraying onto the current collector 2 and the diameter of the spraying end of the nozzle 122 within a reasonable range, the functional medium sprayed from the spraying end of the nozzle 122 can form a more stable non-woven state under the action of the electrostatic field, so that the thickness of the functional layer coated on the surface of the current collector 2 is more uniform.

[0104] In order to control the curing diameter D of the functional layer formed by the nozzle 122 spraying onto the current collector 2 within a reasonable range, the voltage of the electrostatic field is also an important influencing factor for the curing diameter D of the functional layer. The voltage of the electrostatic field determines the diameter and shape of the functional medium. Generally speaking, the higher the voltage, the thinner the diameter of the functional medium and the longer its shape. However, when the voltage is too high, it will cause the functional medium to break or the shape to be unstable.

[0105] In order to further improve the thickness uniformity of the functional layer formed by the spraying module 12 spraying onto the surface of the current collector 2, the voltage of the electrostatic field also needs to be controlled within a suitable range. In some embodiments, the voltage of the electrostatic field can be 5 - 30 kV.

[0106] In the above embodiments, the spraying module 12 can be installed into the die head body 11 not only by the Figures 2 - 5 embedded manner shown, but also can be installed on the surface of the die head body 11 through a connection structure.

[0107] In some embodiments, the die head body 11 is provided with a mounting member, and the spraying module 12 is arranged on the die head body 11 through the mounting member.

[0108] In some embodiments, the mounting member can be a bracket. One end of the bracket is connected to the die head body 11 by welding or bolt fixing, and the other end of the bracket can be connected to the spraying module 12 by bolts. This connection method is convenient for the disassembly of the spraying module 12. In some other embodiments, the mounting member can be a magnetic attraction structure, that is, the die head body 11 is made of steel material, including carbon steel, alloy steel, stainless steel, etc., and the spraying module 12 is made of a magnetic material. The spraying module 12 and the die head body 11 are connected by magnetic attraction. This connection method is simpler. In some other embodiments, the die head body 11 and the spraying module 12 are fixed by glue pasting. This method is more cost-saving.

[0109] In the above embodiments, the mounting member is a component independent of the die head body 11, with low installation difficulty and convenient for the disassembly and replacement of the spraying module 12.

[0110] Please refer to Figure 7 , this application embodiment also provides a coating device 100, and the coating device 100 includes: a coating die head 1, and a back roll 3 for conveying the current collector 2; the back roll 3 is arranged on one side of the coating die head 1.

[0111] The coating die head 1 is used to coat the slurry on the surface of the current collector 2. The back roll 3 can be a rotatable rotating member in the coating device 100. The current collector 2 is wound around the back roll 3, and the back roll 3 is used to make the current collector 2 run smoothly in the coating device 100. The back roll 3 can be a structure symmetric about the axis of the cylinder, and the material of the back roll 3 can be cast steel, cast iron, rubber, etc., which is not limited herein.

[0112] During the process of the back roller 3 rotating to drive the current collector 2 to run the tape, the coating die head 1 can continuously coat the active slurry and spray the functional medium onto the current collector 2 to realize the coating process of the composite electrode sheet and improve the continuity of the coating process of the coating device 100.

[0113] Since the active slurry and the functional medium are usually chemical reagents, volatile substances are likely to be generated when the spraying module 12 sprays the functional medium onto the surface of the current collector 2 and when the die head body 11 coats the active slurry onto the surface of the current collector 2. Therefore, it is necessary to dry the volatile substances generated in the surrounding areas of the coating die head 1 and the back roller 3 so that the coating process always maintains a relatively dry environment.

[0114] In some embodiments, the coating device 100 further includes: a drying unit 4, and the drying unit 4 is used to dry the current collector 2 wound around the back roller 2.

[0115] In some embodiments, the drying unit 4 can be connected by a bracket and fixed around the coating die head 1, or the drying unit 4 is connected by a bracket and fixed around the back roller 3. In other embodiments, the drying unit 4 can be connected by a bracket and fixed in the area between the coating die head 1 and the back roller 3. In the above several embodiments, the drying unit 4 can include a plurality of hot gas supply pipes and diffusion pipes. The hot gas supply pipes are fixedly installed on the diffusion pipes, and the hot gas supply pipes are internally communicated with the diffusion pipes. The external heat source enters the diffusion pipes along the hot gas supply pipes, and the diffusion pipes uniformly diffuse the hot gas. The bottom of the diffusion pipe is provided with a blowing port facing the current collector 2, and the uniformly diffused hot gas is discharged along the blowing port, so that the coating passing under the blowing port can be dried to the desired temperature.

[0116] In other embodiments, the drying unit 4 can also use infrared lamp irradiation, microwave heating drying, and long-wave or short-wave irradiation, etc.

[0117] By setting the drying unit 4, it is possible to timely dry the volatile substances generated by the active slurry layer and the functional layer formed on the surface of the current collector 2 wound around the back roller 3, so that the coating process always maintains a relatively dry environment.

[0118] As mentioned above, when the coating die head 1 coats the active slurry and sprays the functional medium, the generated volatile substances usually also contain some volatile gases. If these volatile gases are inhaled by the human body, it will cause certain harm to the human body. Therefore, in order to timely collect and discharge these volatile gases, in some embodiments, the coating device 100 further includes: an exhaust unit 5, and the exhaust unit 5 is used to collect and process the volatile gases generated during the coating of the coating device 100.

[0119] In some embodiments, the exhaust unit 5 may include a vacuum pump and a motor, and is disposed around the coating die head 1. By starting the motor to drive the vacuum pump to pump air, the volatile gases generated by the active slurry coated by the coating die head 1 and the functional medium sprayed are sucked away, so as to keep the area of the coating die head 1 dry. In some other embodiments, the exhaust unit 5 includes a vacuum pump and a motor, and is disposed around the back roller 3. By starting the motor to drive the vacuum pump to pump air, the volatile gases generated by the active slurry layer and the functional layer formed on the surface of the current collector 2 are sucked away, so as to keep the area of the back roller 3 dry. In other embodiments, the exhaust unit 5 includes a vacuum pump and a motor, and is disposed in the area between the coating die head 1 and the back roller 3. By starting the motor to drive the vacuum pump to pump air, the volatile gases generated by the active slurry coated by the coating die head 1 and the functional medium sprayed, and the volatile gases generated by the active slurry layer and the functional layer formed on the surface of the current collector 2 wound around the back roller 3 are all sucked away, so as to keep the areas around the coating die head 1 and the back roller 3 dry.

[0120] In some other embodiments, the exhaust unit 5 may also be an exhaust structure fixedly installed in the area between the coating die head 1 and the back roller 3 through a bracket. The exhaust structure includes: an exhaust duct and a fan. The fan is disposed in the exhaust duct. By controlling the rotation of the fan to generate negative pressure, the volatile gases generated during the coating of the coating device 100 are extracted and discharged from the exhaust duct.

[0121] By providing the exhaust unit 5, not only can the volatile gases mixed in the volatile substances generated when the injection module 12 coats the active slurry and sprays the functional medium be processed in a timely manner, but also the volatile gases of the volatile substances generated by the active slurry layer and the functional layer formed on the surface of the current collector 2 wound around the back roller 3 can be collected and processed in a timely manner, so as to realize the timely collection and processing of the volatile gases generated during the coating of the coating device 100, reduce the harm caused by the volatile gases to the human body, and reduce the pollution to the air.

[0122] The drying unit 4 and the exhaust unit 5 in the above embodiments can be separately and independently provided and operate independently. In some other embodiments, the drying unit 4 and the exhaust unit 5 can operate simultaneously. As an example, the exhaust unit 5 is connected to the drying unit 4. The exhaust unit 5 and the drying unit 4 are integrally provided. Specifically, the drying unit 4 can be fixed on the exhaust unit 5 by means of bolt connection. The surrounding areas of the coating die head 1 and the back roller 3 are dried by the drying unit 4, and the volatile gases generated during the coating of the coating device 100 are sucked away by the exhaust unit 5, so as to keep the environmental temperature during the coating of the coating device 100 at a suitable temperature and make the coating device 100 in a dry environment free from the influence of gases.

[0123] In some embodiments, the coating device 100 further includes: a feeding device 6 and a conveying driving device 7; the feeding device 6 is connected to the coating die head 1, and the feeding device 6 is used to provide coating slurry for the coating die head 1. The coating slurry includes active slurry and functional medium. The conveying driving device 7 is connected to the back roller 3, and the conveying driving device 7 is used to drive the back roller 3 to rotate to drive the current collector 2 to rotate.

[0124] The feeding device 6 has a feeding port, and a cavity is formed on the die head body 11. The feeding port of the feeding device 6 is respectively communicated with the cavity of the die head body 11 and the spraying module 12. According to the types of the coating slurry, the feeding device 6 can be set to at least two, which are respectively used to contain the active slurry and the functional medium. Among them, the active slurry enters the cavity of the die head body 11 through the feeding port of the feeding device 6 containing the active slurry, and is sprayed out of the coating die head 1 through the discharge port 114 at the slit. The functional medium enters the spraying module 12 through the feeding port of the feeding device 6 containing the functional medium, and the functional medium passes through the channel 121 of the spraying module 12 and is sprayed out of the coating die head 1 after passing through the nozzle 122.

[0125] The feeding device 6 can timely and continuously provide coating slurry for the coating die head 1, and the conveying driving device 7 drives the back roller 3 to rotate, which is convenient for the back roller 3 to drive the current collector 2 to continuously run the tape.

[0126] To facilitate the conveying and storage of the current collector 2, in some embodiments, the conveying driving device 7 further includes: an unwinding mechanism 71 and a winding mechanism 72; the unwinding mechanism 71 is used to convey the current collector 2 to the back roller 3, and the winding mechanism 72 is used to store the coated current collector 2.

[0127] In some embodiments, along the moving direction of the current collector 2 to be coated, the unwinding mechanism 71 can be arranged on the side away from the coating die head 1, and the unwinding mechanism 71 is used to convey the current collector 2 to the back roller 3. Along the moving direction of the current collector 2 to be coated, the winding mechanism 72 is arranged on the side away from the coating die head 1, and the winding mechanism 72 is used to store the current collector 2 that has been conveyed from the back roller 3 and has been coated. The arrangement positions of the unwinding mechanism 71 and the winding mechanism 72 can be flexibly designed, and can be specifically set according to the coating process requirements of the coating device 100. Here, the setting positions of the unwinding mechanism 71 and the winding mechanism 72 are not specifically limited.

[0128] Specifically, the current collector 2 is accommodated in the unwinding mechanism 71 and is configured to be wound around the unwinding mechanism 71. The current collector 2 released from the unwinding mechanism 71 bypasses the back roller 3 and is connected to the winding mechanism 72 under the traction of the back roller 3. The current collector 2 is accommodated in the winding mechanism 72 and is configured to be in a state that can be accommodated by the winding mechanism 72. In some embodiments, the unwinding mechanism 71 and the winding mechanism 72 can be respectively located at both ends of the moving direction of the current collector 2, or both located on the side away from the coating die head 1.

[0129] Through the mutual cooperation of the unwinding mechanism 71 and the winding mechanism 72, the conveying and storage efficiency of the current collector 2 can be improved, and further the coating efficiency of the coating device 100 is improved.

[0130] In order to improve the tension and traction force when the unwinding mechanism 71 and the winding mechanism 72 traction the current collector 2, in some embodiments, at least one traction roller can be provided between the unwinding mechanism 71 and the back roller 3, and at least one traction roller can be provided between the winding mechanism 72 and the back roller 3. By providing a plurality of traction rollers, the tension and traction force when the current collector 2 runs the tape are improved, and the running of the current collector 2 is smoother.

[0131] The coating device 100 in each embodiment can be coated according to the following coating process. Taking Figure 2 and Figure 5 the structure of the coating die head 1 shown as an example to illustrate the coating process, as follows:

[0132] First, control the unwinding mechanism 71, the winding mechanism 72, and the back roller 3 to start moving simultaneously. The unwinding mechanism 71 conveys the current collector 2 towards the back roller 3, so that the current collector 2 is wound around the back roller 3, and the rotation of the back roller 3 drives the current collector 2 to move towards the winding mechanism 72. While starting the unwinding mechanism 71 and the winding mechanism 72, control the feeding device 6 to start feeding. The raw materials provided by the feeding device 6 include: active slurry and functional medium.

[0133] According to the functions required to be achieved by the current collector 2 to be coated, the corresponding functional medium can be selected and conveyed into the feeding device 6. As an example, when the current collector 2 to be coated needs to improve the battery capacity, the active lithium material can be coated on the surface of the current collector 2. Specifically, the active lithium functional medium and the active slurry are respectively added into the two feeding devices 6. Among them, the active slurry is coated out of the coating die head 1 from the discharge port of the slit formed between the first die head 111, the second die head 112, and the gasket 113, and is coated towards the surface direction of the current collector 2; the active lithium functional medium is sprayed out of the coating die head 1 through the spraying module 12 located in the first die head 111 or the spraying module 12 located in the second die head 112, and is coated towards the surface direction of the current collector 2.

[0134] During the coating process of the coating die head 1, by controlling the spraying module 12 in the first die head 111, the spraying module 12 in the second die head 112, and the sequential coating order of the active slurry, the coating position or coating layer of the active slurry layer and the functional layer formed on the surface of the current collector 2 is controlled to realize the preparation of the composite electrode sheet.

[0135] As a first embodiment, after the conveying drive device 7 starts cyclic rotation, the current collector 2 wound around the back roller 3 rotates clockwise to the position where the second die head 112 is located. By controlling the solenoid valve of the nozzle 122 in the injection module 12 in the second die head 112 to open first, the active lithium functional medium is injected. At the same time, the injection module 12 in the first die head 111 is controlled to close. Under the action of the electrostatic field, the active lithium functional medium ejected from the injection module 12 in the second die head 112 is stretched under the action of the electrostatic field and forms the first lithium compensation layer functional layer on the surface of the current collector 2.

[0136] When the back roller 3 drives the current collector 2 coated with the first lithium compensation layer functional layer to rotate to the discharge port 114 between the first die head 111 and the second die head 112, the active slurry is ejected from the discharge port 114 and is coated on the outer surface of the first lithium compensation layer functional layer of the current collector 2. At this time, two coating material layers have been formed on the surface of the current collector 2: from the surface of the current collector 2 from the inside to the outside, they include the first lithium compensation layer functional layer and the active slurry layer in sequence. It can be understood that the first lithium compensation layer functional layer is located below the active slurry layer.

[0137] When the back roller 3 continues to drive the current collector 2 to rotate to the position where the first die head 111 is located, the injection module 12 in the first die head 111 is controlled to open. Under the action of the electrostatic field, the active lithium functional medium ejected from the injection module 12 in the first die head 111 is stretched under the action of the electrostatic field and continues to coat the second lithium compensation layer functional layer on the outer surface of the current collector 2 coated with the active slurry layer. At this time, three coating material layers have been formed on the surface of the current collector 2: from the surface of the current collector 2 from the inside to the outside, they include: the first lithium compensation layer functional layer, the active slurry layer, and the second lithium compensation layer functional layer in sequence. It can be understood that the first lithium compensation layer functional layer is located below the active slurry layer, and the second lithium compensation layer functional layer is located above the active slurry layer.

[0138] It should be noted that after the injection module 12 in the first die head 111 is opened for injection, the injection module 12 in the second die head 112 always remains open, and the discharge port 114 continues to eject the active slurry until the unwinding mechanism 71 unwinds all the current collectors 2 and the winding mechanism 72 completely receives the current collectors 2, and the coating device 100 completes the coating process of the current collector 2. The current collector 2 formed after the coating device 100 is coated is a composite pole piece composite with three coating material layers.

[0139] As a second embodiment, when the current collector 2 wound around the back roller 3 rotates clockwise to the position of the discharge port 114 between the first die head 111 and the second die head 112, the active slurry is first ejected from the discharge port 114, and the active slurry is coated on the outer surface of the current collector 2. When the back roller 3 continues to drive the current collector 2 to rotate to the position of the first die head 111, at this time, the injection module 12 in the first die head 111 is controlled to be turned on. Under the action of the electrostatic field, the active lithium functional medium ejected from the injection module 12 in the first die head 111 is stretched under the action of the electrostatic field, and the lithium supplement layer functional layer is continuously coated on the outer surface of the current collector 2 where the active slurry layer has been coated. At this time, two coated material layers have been formed on the surface of the current collector 2: from the inner to the outer surface of the current collector 2, they successively include: the active slurry layer and the lithium supplement layer functional layer. It can be understood that the lithium supplement layer functional layer is located above the active slurry layer.

[0140] After the injection module 12 in the first die head 111 is turned on for injection, the discharge port 114 continues to coat the active slurry until the unwinding mechanism 71 has unwound all the current collectors 2, and the winding mechanism 72 has completely wound up the current collectors 2, and the coating device 100 has completed the coating process of the current collectors 2. The current collector 2 formed after the coating device 100 is coated is a composite electrode sheet composite with two coated material layers.

[0141] As a third embodiment, the injection module 12 in the second die head 112 in the first embodiment can be used to inject a plasticizer. When the transmission driving device 7 starts to rotate in a cycle, the current collector 2 wound around the back roller 3 rotates clockwise to the position of the second die head 112. By controlling the electronic valve of the nozzle 122 in the injection module 12 in the second die head 112 to be turned on first, the plasticizer is injected. At the same time, the injection module 12 in the first die head 111 is controlled to be turned off. Under the action of the electrostatic field, the plasticizer functional medium ejected from the injection module 12 in the second die head 112 is stretched under the action of the electrostatic field and a plasticizer functional layer is formed on the surface of the current collector 2.

[0142] When the back roller drives the current collector 2 coated with the plasticizer functional layer to rotate to the discharge port 114 between the first die head 111 and the second die head 112, the discharge port 114 ejects the active slurry, and the active slurry is coated on the outer surface of the plasticizer functional layer of the current collector 2. At this time, two coated material layers have been formed on the surface of the current collector 2: from the inner to the outer surface of the current collector 2, they successively include the plasticizer functional layer and the active slurry layer. It can be understood that the plasticizer functional layer is located below the active slurry layer.

[0143] When the back roller 3 continues to rotate and drives the current collector 2 to rotate to the position where the first die head 111 is located, control the injection module 12 in the first die head 111 to open. Under the action of the electrostatic field, the active lithium functional medium ejected by the injection module 12 in the first die head 111 is stretched under the action of the electrostatic field, and the lithium replenishing layer functional layer is continuously coated on the outer surface of the current collector 2 where the active slurry layer has been coated. At this time, three coated material layers have been formed on the surface of the current collector 2: from the inner to the outer surface of the current collector 2, they include: the plasticizer functional layer, the active slurry layer, and the lithium replenishing layer functional layer. It can be understood that the plasticizer functional layer is located under the active slurry layer, and the lithium replenishing layer functional layer is located above the active slurry layer.

[0144] After the injection module 12 in the first die head 111 is opened for injection, the injection module 12 in the second die head 112 always remains open, and the discharge port 114 continues to apply the active slurry until the unwinding mechanism 71 unwinds all the current collectors 2, and the winding mechanism 72 completely receives the current collectors 2, and the coating device 100 completes the coating process of the current collectors 2. The current collector 2 formed after the coating device 100 is coated is a composite pole piece composite with three coated material layers.

[0145] In the above three embodiments, by controlling the injection module 12 in the first die head 111, the injection module 12 in the second die head 112, and the sequential coating order of the active slurry, the coating position or coating layer of the active slurry layer and the functional layer formed on the surface of the current collector 2 is controlled, so as to realize the required functional layer on the surface of the current collector 2 according to the coating process requirements, so as to realize the synchronous composite of the functional layer and the active slurry layer. It should be noted that in the above three embodiments, the drying unit 4 and the exhaust unit 5 can be simultaneously turned on and operated to provide a suitable temperature environment for the coating process of the coating device 100.

[0146] Take Figure 3 and Figure 5 The structure of the coating die head 1 shown is used to illustrate the coating process as follows: First, control the unwinding mechanism 71, the winding mechanism 72, and the back roller 3 to start moving simultaneously. The unwinding mechanism 71 conveys the current collector 2 towards the back roller 3, so that the current collector 2 is wound around the back roller 3. While the unwinding mechanism 71 and the winding mechanism 72 are turned on, control the feeding device 6 to start feeding.

[0147] According to the functions to be achieved by the current collector 2 to be coated, the corresponding functional medium can be selected and conveyed into the feeding device 6. Figure 3The shown die head body 11 includes a first die head 111, a second die head 112, and a third die head 116, and the injection modules 12 in each die head can be controlled to inject the same or different functional media. At the same time, the coating sequence of the injection modules 12 and the die head body 11 in each die head can be controlled to control the coating position or coating layer position of the active slurry layer and the functional layer formed on the surface of the current collector 2. For the specific coating process and principle, reference can be made to the descriptions in the foregoing first embodiment, second embodiment, and third embodiment, and details will not be repeated here.

[0148] Through Figure 3 The shown coating die head 1 can not only realize the preparation of composite electrodes with single-layer, two-layer, and three-layer coating material layers, but can even realize the preparation of composite electrodes with more coating material layers, and has a wider application scenario.

[0149] In summary, by integrating the injection module 12 with the die head body 11, the coating die head 1 of the present application can be used to form an active slurry layer on the surface of the current collector by the die head body 11 and form a functional layer by injecting the injection module 12 onto the current collector, so as to construct the required functional layer on the surface of the current collector 2.

[0150] By controlling the coating sequence of the injection module 12 and the die head body 11 on the die head body 11, the compounding of the injected functional layer at different positions of the active slurry layer is realized, so as to realize the one-step formation of the composite electrode, reduce the processes of the coating process, and improve the efficiency of the coating process.

[0151] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, 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 die head, characterized in that: include: A die body, wherein the die body is used to coat the current collector to form an active slurry layer; The injection module is arranged on the die body, and is used for spraying toward the collector to form a functional layer located above or below the active slurry layer.

2. The coating die head according to claim 1, characterized in that: The injection module is an electrostatic spinning module.

3. The coating die head according to claim 1 or 2, characterized in that: The injection module comprises: a channel and a nozzle; The die body is provided with a mounting groove, the channel is arranged in the mounting groove, and the nozzle is arranged on a side of the channel close to the current collector.

4. The coating die head according to claim 3, characterized in that: The injection modules are provided in plurality, and the plurality of injection modules are arranged at intervals.

5. The coating die head according to claim 1, characterized in that: The injection module is a centrifugal electrospinning module.

6. The coating die head according to claim 1, characterized in that: The die body comprises: a first die, a second die, and a gasket arranged between the first die and the second die; the first die and / or the second die is provided with the injection module.

7. The coating die head according to claim 1, characterized in that: The die body comprises: a first die, a second die, a third die, a first gasket disposed between the first die and the second die, and a second gasket disposed between the second die and the third die; At least one of the first die, the second die, and the third die is provided with the injection module.

8. The coating die head according to claim 1, characterized in that: The die body is provided with a mounting piece, and the injection module is arranged on the die body through the mounting piece.

9. A coating device, characterized in that: It comprises a coating die head as described in any one of claims 1 to 8, and a back roller for conveying the current collector; the back roller is arranged on one side of the coating die head.

10. The coating device according to claim 9, characterized in that: The coating device further includes: a drying unit, which is used to dry the current collector passing around the backing roller.

11. The coating device according to claim 10, characterized in that: The coating device further comprises: an exhaust unit, which is used to collect and process volatile gases generated when the coating device is coating.

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