A coating system for conductive paste

Abstract

The present invention discloses a coating system for conductive slurry, including a coating machine and a feeding device, wherein the coating machine includes a frame, a belt roller, a lower pressure roller, a transmission roller and a slurry pool, wherein the belt roller, the lower pressure roller and the transmission roller are connected to the frame, the slurry pool is arranged below the belt roller, the lower pressure roller is arranged above the belt roller, and the belt roller is provided with a recessed area and a non-recessed area; the feeding device includes a storage tank, a power device and an iron remover, wherein the storage tank is used to store conductive slurry, the power device is connected between the storage tank and the iron remover, and the conductive slurry in the storage tank is transported to the iron remover, and the iron remover transports the conductive slurry after iron removal to the slurry pool through a pipeline. The coating system of the present invention effectively removes iron and impurities in the conductive slurry, and can form a conductive coating with a thickness of less than 120nm on a metal foil.

Description

Technical Field

[0001] The invention relates to the technical field of secondary batteries, and in particular to a coating system for conductive slurry. Background Art

[0002] Secondary batteries are represented by lithium-ion batteries. Due to their excellent comprehensive performance, they have always occupied an important position in the 3C consumer field, new energy power batteries, and large-scale energy storage batteries.

[0003] The current collector of a secondary battery such as a lithium-ion battery refers to a structure or part that collects current. In lithium-ion batteries, it mainly refers to metal foil, such as copper foil and aluminum foil. It can also generally include the tabs. Its main function is to collect the current generated by the active material of the battery in order to form a larger current output. Therefore, the current collector should be in full contact with the active material, and the internal resistance should be as small as possible.

[0004] In the existing technology, using functional coating to treat the surface of the battery conductive substrate is a breakthrough technological innovation. Carbon-coated aluminum foil / copper foil is to evenly and delicately coat the dispersed nano-conductive graphite, carbon-coated particles, carbon nanotubes and other conductive materials on the aluminum foil / copper foil. It can provide excellent static conductivity and collect the micro-current of active substances, thereby greatly reducing the contact resistance between the positive / negative electrode materials and the current collector, and can improve the fixation ability between the two, which can reduce the use of binders, thereby significantly improving the overall performance of the battery.

[0005] Existing carbon-coated foils are made by mixing conductive materials such as graphite, carbon black, multi-layer carbon nanotubes, and dispersants and binders in different proportions to form a conductive paste that is evenly dispersed and coated on metal foils such as aluminum foil or copper foil. Existing conductive pastes are directly transported from storage tanks to coating machines for coating. Since the conductive pastes contain impurities such as iron, they will affect the thickness and performance of the coating, and are also prone to clogging the nozzles of the coating machines, thereby affecting the performance of the current collectors.

[0006] In addition, in the existing coating machine for coating the conductive paste on the metal foil, the belt roller cannot control the amount of the conductive paste coated on the metal foil, so the thickness of the conductive coating formed on the metal foil is generally greater than 120nm, and a thin conductive coating cannot be formed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a coating system for conductive paste, which can effectively remove iron and impurities in the conductive paste and form a conductive coating with a thickness of less than 120nm on a metal foil.

[0008] In order to solve the above technical problems, the present invention provides a coating system for conductive slurry, including a coating machine and a feeding device, wherein the coating machine includes a frame, a belt roller, a lower pressure roller, a transmission roller and a slurry pool, wherein the belt roller, the lower pressure roller and the transmission roller are connected to the frame, the slurry pool is arranged below the belt roller, the lower pressure roller is arranged above the belt roller, the belt roller is provided with a recessed area and a non-recessed area, the recessed area is recessed inwardly to a preset depth along the surface of the belt roller, the recessed area is coated with a ceramic coating, and the ceramic coating is provided with a plurality of recessed holes;

[0009] The feeding device comprises a storage tank, a power device and an iron remover, wherein the storage tank is used to store the conductive slurry, the power device is connected between the storage tank and the iron remover, and the conductive slurry in the storage tank is transported to the iron remover, and the iron remover transports the conductive slurry after iron removal to the slurry pool through a pipeline;

[0010] Among them, the iron remover includes a shell, an upper cover, and a magnetic rod connected to the upper cover. The shell is provided with a accommodating cavity. The upper cover is closed on the shell, and the magnetic rod is inserted into the accommodating cavity. The side wall of the magnetic rod is provided with a plurality of magnetic strips extending outwardly, and the angle between the magnetic strips and the magnetic rod is 12 to 3 degrees.

[0011] As an improvement of the above solution, the recessed area has a depth of 1 to 10 mm.

[0012] As an improvement of the above solution, the thickness of the ceramic coating is 3 to 15 mm.

[0013] As an improvement of the above solution, at least two recessed areas are provided, wherein the recessed areas and non-recessed areas are alternately arranged.

[0014] As an improvement of the above solution, the belt roller, the lower pressure roller and the transmission roller are rotatably connected to the frame via a rotating shaft.

[0015] As an improvement of the above solution, the material of the belt roller is stainless steel.

[0016] As an improvement of the above scheme, the magnetic strip is spirally arranged around the magnetic rod from top to bottom, and the shell is provided with a feed port and a discharge port. The feed port is arranged above the shell, and the discharge port is arranged below the shell on the opposite side of the feed port.

[0017] As an improvement of the above solution, the distance between the magnetic strips is 5% to 16% of the height of the accommodating cavity.

[0018] As an improvement of the above solution, the upper cover is provided with a hanging ring, and the magnetic rod is slidably connected with the hanging ring via a slider.

[0019] As an improvement of the above solution, a plurality of concave holes are provided on the magnetic strip, and the depth of the concave holes is 1 to 5 mm.

[0020] The implementation of the present invention has the following beneficial effects:

[0021] The coating system of the present invention effectively removes iron and impurities in the conductive slurry through the cooperation between the feeding device and the coating machine, so as to form a conductive coating with a thickness of less than 120nm on the metal foil. Among them, the iron remover in the feeding device is provided with a magnetic strip on the side wall of the magnetic rod to increase the contact area between the magnetic rod and the conductive slurry, and effectively removes iron and impurities in the conductive slurry, so that a conductive coating with a thinner thickness can be formed; in addition, the coating machine is provided with a recessed area on the belt roller, and a ceramic coating is formed on the recessed area, so that the conductive slurry after iron removal is coated on the metal foil through the ceramic coating, thereby forming a conductive coating. Among them, the present invention is provided with a plurality of recessed holes on the ceramic coating to reduce the amount of conductive slurry adhered to the ceramic coating, thereby forming a conductive coating with an ultra-thin thickness.

[0022] The present invention further reduces the amount of conductive paste adhered to the ceramic coating by designing the recessed depth of the recessed area and the thickness of the ceramic coating, so as to form a conductive coating with a thickness of 140 to 150 nm on a single side of the metal foil.

[0023] The magnetic strip of the present invention is spirally arranged around the magnetic rod from top to bottom, and a feed port is arranged above the shell, and a discharge port is arranged below the shell on the opposite side of the feed port. Through the cooperation of the magnetic rod, the magnetic strip, the feed port and the discharge port, the conductive slurry enters from the feed port and flows in a vortex manner in the accommodating cavity, so that the fluidity of the conductive slurry can be enhanced without rotating the magnetic rod, and the contact efficiency between the conductive slurry and the magnetic rod and the magnetic strip is enhanced, thereby improving the iron removal effect of the conductive slurry and further enhancing the mixing uniformity of the individual substances in the conductive slurry.

[0024] The present invention arranges a plurality of concave holes on the magnetic strip to increase the contact area between the magnetic strip and the conductive slurry, and at the same time hides iron or other impurities therein, thereby preventing the conductive slurry from washing the iron or other impurities back when flowing, and further improving the iron removal effect of the conductive slurry.

[0025] The present invention arranges a plurality of through holes and concave holes on the magnetic strip, and arranges the through holes and the concave holes alternately. The present invention further reduces the friction between the magnetic strip and the conductive slurry through the through holes, and increases the contact area between the magnetic strip and the conductive slurry, thereby further improving the iron removal effect of the conductive slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the new coating system of the present utility model;

[0027] Figure 2It is a schematic structural diagram of the belt roller of the coating machine of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the iron remover of the present invention;

[0029] Figure 4 It is a top view of the magnetic rod and magnetic strip of the iron remover of the present invention. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] See also Figure 1 and Figure 2 The present invention provides a conductive paste coating system, comprising a coating machine 1 and a feeding device 2, wherein the coating machine 1 comprises a frame 11, a belt roller 12, a lower pressure roller 13, a transmission roller 14 and a slurry pool 15, wherein the belt roller 12, the lower pressure roller 13 and the transmission roller 14 are connected to the frame 11, the slurry pool 15 is arranged below the belt roller 12, the lower pressure roller 13 is arranged above the belt roller 12, the belt roller 12 is provided with a recessed area 121 and a non-recessed area 122, and the recessed area 121 is arranged along the belt roller The surface of 12 is recessed inward to a preset depth, the recessed area 121 is coated with a ceramic coating 123, and the ceramic coating 123 is provided with a plurality of recessed holes 1231; the feeding device 2 comprises a storage tank 21, a power device 22 and an iron remover 23, the storage tank 21 is used to store conductive slurry, the power device 22 is connected between the storage tank 21 and the iron remover 22, and the conductive slurry in the storage tank 21 is transported to the iron remover 23, and the iron remover 23 transports the conductive slurry after iron removal to the slurry pool 15 through a pipeline.

[0032] Specifically, the power device 22 is connected to the storage tank 21 and the iron remover 23 through a pipeline, and is used to control the conveying speed and flow rate of the conductive slurry. Preferably, the power device 22 is a peristaltic pump, but is not limited thereto.

[0033] The slurry pool 15 is used to hold the conductive slurry, and the metal foil 3 to be coated is arranged between the lower pressure roller 13 and the belt roller 12 through the driving roller 14. When the lower pressure roller 13 is pressed downward toward the belt roller 12, the recessed area 121 of the belt roller 12 coats the conductive slurry in the slurry pool 15 on the metal foil 3 to form a conductive coating on the metal foil 3. The belt roller 12, the lower pressure roller 13, and the driving roller 14 are rotatably connected to the frame 11 through the rotating shaft 16, and the rotating shaft 16 is driven by a driving device such as a motor 17 to achieve rotation.

[0034] Specifically, during the rotation of the belt roller 12, the conductive slurry in the slurry pool 15 adheres to the ceramic coating 123 in the recessed area 121, and the conductive slurry in the recessed area 121 is coated on the corresponding position of the metal foil 3 to form a conductive coating. Since the ceramic coating 123 of the present invention is provided with a plurality of recessed holes 1231, the amount of conductive slurry on the ceramic coating 123 can be reduced to form an ultra-thin conductive coating.

[0035] The belt roller 12 of the present invention is made of stainless steel, so the non-depressed area 122 of the belt roller 12 will not be adhered to by the conductive slurry after passing through the slurry pool 15, and only the ceramic coating 123 on the non-depressed area 121 will be adhered to by the conductive slurry.

[0036] The recessed depth of the recessed area 121 is h, as Figure 2 As shown, the depression depth of the depression area 121 has an important influence on the thickness of the conductive coating; if the depression depth of the depression area 121 is too shallow, the conductive paste adhered to the depression area 121 is too little, affecting the thickness uniformity of the conductive coating coated on the metal foil 3; if the depression depth of the depression area 121 is too deep, the conductive paste cannot be effectively coated on the metal foil. Preferably, the depression depth of the depression area 121 is 1 to 10 mm. More preferably, the depression depth of the depression area 121 is 3 to 7 mm, which can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, etc.

[0037] In addition, the thickness of the ceramic coating 123 also has an important influence on the thickness of the conductive coating; if the thickness of the ceramic coating 123 is too thin, the depth of the concave holes on the ceramic coating is too shallow, and the conductive slurry adhering to the ceramic coating 123 is too little, affecting the thickness uniformity of the conductive coating coated on the metal foil 3; if the thickness of the ceramic coating 123 is too thick, the ceramic coating 123 is prone to adhere to too much conductive slurry, and the thickness of the conductive coating formed is too thick. Preferably, the thickness of the ceramic coating 123 is 3 to 15 mm. More preferably, the thickness of the ceramic coating 123 is 5 to 10 mm, which can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.

[0038] In order to improve production efficiency, at least two recessed areas 121 are provided, wherein the recessed areas 121 and the non-recessed areas 122 are alternately arranged.

[0039] In order to ensure that the belt roller 12 can form the recessed area 121 and the recessed hole 1231 and to ensure that the belt roller 12 can adhere the conductive paste to the metal foil 3 , the material of the belt roller 12 is stainless steel.

[0040] See also Figure 3The iron remover 23 includes a shell 231, an upper cover 232, and a magnetic rod 233 connected to the upper cover 232. The shell 231 is provided with a accommodating cavity 2311. The upper cover 232 is covered on the shell 231, and the magnetic rod 233 is inserted into the accommodating cavity 2311. The magnetic rod 233 absorbs magnets, impurities, etc. in the conductive slurry in the accommodating cavity 2311 by magnetic methods.

[0041] Specifically, the side wall of the magnetic rod 233 is provided with a plurality of magnetic strips 2331 extending outwardly at an angle, and the angle between the magnetic strips 2331 and the magnetic rod 233 is 20 to 60 degrees. The present invention arranges the magnetic strips 2331 on the side wall of the magnetic rod 233, which can increase the contact area between the magnetic rod 233 and the conductive slurry and improve the iron removal effect of the conductive slurry.

[0042] Preferably, the magnetic stripe 2331 is spirally arranged around the magnetic rod 233 from top to bottom, and the shell 231 is provided with a feed port 2312 and a discharge port 2313. The feed port 2312 is arranged above the shell 231, and the discharge port 2313 is arranged below the shell 231 on the opposite side of the feed port 2312. With the cooperation of the magnetic rod 233, the magnetic stripe 2331, the feed port 2312 and the discharge port 2313, the conductive slurry enters from the feed port 2312 and flows in a vortex manner in the accommodating cavity 2311. In this way, without rotating the magnetic rod 233, the fluidity of the conductive slurry can be enhanced, and the contact efficiency between the conductive slurry and the magnetic rod 233 and the magnetic stripe 2331 can be enhanced, thereby improving the iron removal effect of the conductive slurry and further enhancing the mixing uniformity of the individual substances in the conductive slurry.

[0043] If the conductive slurry flows too fast in the receiving chamber 2311, the friction between the conductive slurry and the shell 231, the magnetic rod 233 and the magnetic strip 2331 will increase, which will affect the iron removal effect and performance of the conductive slurry. In addition to controlling the flow rate of the conductive slurry by a power device, the present invention can also control the flow rate of the conductive slurry in the receiving chamber 2311 by the distribution of the magnetic strips 2331. Specifically, the distance between the magnetic strips 2331 is 5% to 16% of the height of the receiving chamber 2311. Preferably, the distance between the magnetic strips 2331 is 7% to 13% of the height of the receiving chamber 2311.

[0044] The upper cover 232 is provided with a hanging ring 2321, and the magnetic rod 233 is slidably connected with the hanging ring 2321 through a slider 234. Specifically, the slider 234 passes through the hanging ring 2321. Since the hanging ring 21 has a certain curvature, the slider 234 can drive the magnetic rod 233 to swing left and right along the hanging ring 2321. In this way, the conductive slurry can be further stirred, and the contact efficiency between the conductive slurry and the magnetic rod 233 and the magnetic strip 2331 can be enhanced, thereby improving the iron removal effect of the conductive slurry, and further enhancing the mixing uniformity of the individual substances in the conductive slurry.

[0045] See also Figure 4 The magnetic strip 2331 is provided with a plurality of recessed holes 2332, which can not only increase the contact area between the magnetic strip 2331 and the conductive slurry, but also hide iron or other impurities therein, thereby preventing the conductive slurry from washing the iron or other impurities back when flowing, and further improving the iron removal effect of the conductive slurry.

[0046] Preferably, the depth of the concave hole 2332 is 1 to 5 mm. More preferably, the depth of the concave hole 2332 is 2 to 4 mm.

[0047] Preferably, the magnetic strip 2331 is further provided with a plurality of through holes 2333, the through holes 2333 penetrate the magnetic strip 2331, and are alternately arranged with the concave holes 2332. The through holes 2333 further reduce the friction between the magnetic strip 2331 and the conductive slurry, and increase the contact area between the magnetic strip 2331 and the conductive slurry, thereby further improving the iron removal effect of the conductive slurry.

[0048] The magnetic rod 233 and the magnetic strip 2331 are an integrally formed structure.

[0049] The coating system of the present invention effectively removes iron and impurities in the conductive slurry through the cooperation between the feeding device and the coating machine, so as to form a conductive coating with a thickness of less than 120nm on the metal foil. Among them, the iron remover in the feeding device is provided with a magnetic strip on the side wall of the magnetic rod to increase the contact area between the magnetic rod and the conductive slurry, and effectively removes iron and impurities in the conductive slurry, so that a conductive coating with a thinner thickness can be formed; in addition, the coating machine is provided with a recessed area on the belt roller, and a ceramic coating is formed on the recessed area, so that the conductive slurry after iron removal is coated on the metal foil through the ceramic coating, thereby forming a conductive coating. Among them, the present invention is provided with a plurality of recessed holes on the ceramic coating to reduce the amount of conductive slurry adhered to the ceramic coating, thereby forming a conductive coating with an ultra-thin thickness.

[0050] The present invention further reduces the amount of conductive paste adhered to the ceramic coating by designing the recessed depth of the recessed area and the thickness of the ceramic coating, so as to form a conductive coating with a thickness of 140 to 150 nm on a single side of the metal foil.

[0051] The magnetic strip of the present invention is spirally arranged around the magnetic rod from top to bottom, and a feed port is arranged above the shell, and a discharge port is arranged below the shell on the opposite side of the feed port. Through the cooperation of the magnetic rod, the magnetic strip, the feed port and the discharge port, the conductive slurry enters from the feed port and flows in a vortex manner in the accommodating cavity, so that the fluidity of the conductive slurry can be enhanced without rotating the magnetic rod, and the contact efficiency between the conductive slurry and the magnetic rod and the magnetic strip is enhanced, thereby improving the iron removal effect of the conductive slurry and further enhancing the mixing uniformity of the individual substances in the conductive slurry.

[0052] The present invention arranges a plurality of concave holes on the magnetic strip to increase the contact area between the magnetic strip and the conductive slurry, and at the same time hides iron or other impurities therein, thereby preventing the conductive slurry from washing the iron or other impurities back when flowing, and further improving the iron removal effect of the conductive slurry.

[0053] The present invention arranges a plurality of through holes and concave holes on the magnetic strip, and arranges the through holes and the concave holes alternately. The present invention further reduces the friction between the magnetic strip and the conductive slurry through the through holes, and increases the contact area between the magnetic strip and the conductive slurry, thereby further improving the iron removal effect of the conductive slurry.

[0054] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A conductive paste coating system, characterized in that: The coating machine comprises a coating machine and a feeding device, wherein the coating machine comprises a frame, a belt roller, a lower pressure roller, a driving roller and a slurry pool, wherein the belt roller, the lower pressure roller and the driving roller are connected to the frame, the slurry pool is arranged below the belt roller, the lower pressure roller is arranged above the belt roller, the belt roller is provided with a recessed area and a non-recessed area, the recessed area is recessed inwardly to a preset depth along the surface of the belt roller, the recessed area is coated with a ceramic coating, and the ceramic coating is provided with a plurality of recessed holes; The feeding device comprises a storage tank, a power device and an iron remover, wherein the storage tank is used to store the conductive slurry, the power device is connected between the storage tank and the iron remover, and the conductive slurry in the storage tank is transported to the iron remover, and the iron remover transports the conductive slurry after iron removal to the slurry pool through a pipeline; The iron remover comprises a shell, an upper cover, and a magnetic rod connected to the upper cover. The shell is provided with a receiving cavity. The upper cover is closed on the shell, and the magnetic rod is inserted into the receiving cavity. The side wall of the magnetic rod is provided with a plurality of magnetic strips extending outwardly, and the angle between the magnetic strips and the magnetic rod is 20 to 60 degrees. The depression depth of the depression area is 1 to 10 mm; The magnetic strip is spirally arranged around the magnetic rod from top to bottom, and the shell is provided with a feed inlet and a discharge outlet, the feed inlet is arranged above the shell, and the discharge outlet is arranged below the shell on the opposite side of the feed inlet; The distance between the magnetic strips is 5% to 16% of the height of the accommodating cavity; The upper cover is provided with a hanging ring, and the magnetic rod is slidably connected with the hanging ring through a slider; The magnetic strip is provided with a plurality of concave holes, and the depth of the concave holes is 1-5 mm.

2. The conductive paste coating system according to claim 1, characterized in that: The thickness of the ceramic coating is 3-15 mm.

3. The conductive paste coating system according to claim 1, characterized in that: There are at least two recessed areas, wherein the recessed areas and non-recessed areas are alternately arranged.

4. The conductive paste coating system according to claim 1, characterized in that: The belt roller, the lower pressure roller and the transmission roller are rotatably connected to the frame through rotating shafts.

5. The conductive paste coating system according to claim 1, characterized in that: The material of the belt roller is stainless steel.

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