Coating die head, coating machine and coating preparation method

Abstract

The invention discloses a coating die head, a coating machine and a coating preparation method, the coating die head comprises a first die head and a second die head which are oppositely arranged in a spaced mode, and at least two medium flow channels are formed in the two wall faces, facing each other, of the first die head and the second die head; the composite gasket is arranged between the first die head and the second die head and comprises a window gasket and a flow guide gasket; the window gasket is arranged on the side provided with the medium flow channels, and medium windows corresponding to the medium flow channels in a one-to-one mode are formed in the window gasket in a hollowed-out mode; the flow guide gasket is provided with flow guide areas which are the same as the medium windows in number and are independently arranged. In the single group of flow guide areas and medium windows, the flow guide areas cover the medium windows, and the lip sides, facing the coating die head, of the flow guide areas are of opening structures. According to the coating die head, at least two medium runners are arranged, and each medium runner is independently communicated with different flow guide areas through the composite gasket, so that the lip side of the coating die head can be synchronously coated with coatings made of different materials, and the complex partition coating requirement in single-time coating is met.

Description

Technical Field

[0001] The present application relates to the field of coating processing, and particularly relates to a coating die head, a coating machine, and a coating preparation method. Background Art

[0002] Coating manufacturing is a technology for generating a protective or functional material layer on the surface of a target substrate through methods such as ultrasonic spraying, pulse spraying, spin coating, and slot coating. Among them, slot coating is an efficient technology suitable for large-scale roll-to-roll batch coating, and is widely used in the fields of fuel cells and lithium-ion batteries due to its good film formation consistency and few coating defects. However, with the gradual increase in coating requirements, the current slot coating method is difficult to meet the requirements of coating lamination, coating zoning, etc. in a single coating process, and needs to be realized through multiple coating processes based on a conventional coating die head, and each coating operation requires precise repositioning, resulting in high operation difficulty and low production efficiency.

[0003] Therefore, how to meet the preparation requirements of complex zoned coatings in a single coating process by means of slot coating is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a coating die head, a coating machine, and a coating preparation method to meet the preparation requirements of complex zoned coatings in a single coating process by means of slot coating.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] A coating die head includes:

[0007] A first die head and a second die head that are opposite and spaced apart, and at least two medium flow channels are jointly opened on two opposite wall surfaces of the first die head and the second die head;

[0008] A composite gasket, which is clamped between the first die head and the second die head, and the composite gasket includes at least one window gasket and at least one flow guiding gasket;

[0009] The window gasket is arranged on one side of the first die head and the second die head where the medium flow channels are opened, and a medium window corresponding to the medium flow channels is hollowed out on the window gasket, and the medium window only covers a partial area of the medium flow channel in the length direction of the medium flow channel; a flow guiding area is opened on the flow guiding gasket, the number of the flow guiding areas is the same as that of the medium windows, and a plurality of the flow guiding areas are independently arranged; in a single group of the flow guiding area and the medium window, the flow guiding area covers the medium window, and the flow guiding area is an open structure towards the lip side of the coating die head.

[0010] Preferably, in the above-mentioned coating die head, independent first and second medium flow channels are spaced apart on the first die head, and the second die head has a flat plate structure;

[0011] The composite gasket includes a first window gasket and a first flow guiding gasket stacked together. The first window gasket is attached to the first die head, and a first medium window and a second medium window are formed on the first window gasket. The width of the first medium window is not less than the width of the first medium flow channel and coincides with a partial length region of the first medium flow channel; the width of the second medium window is not less than the width of the second medium flow channel and coincides with a partial length region of the second medium flow channel; a first flow guiding region and a second flow guiding region are provided on the first flow guiding gasket. The projection of the first medium window in the first flow guiding region is located within the first flow guiding region, and the projection of the second medium window in the second flow guiding region is located within the second flow guiding region.

[0012] Preferably, in the above-mentioned coating die head, the opening distance of the first flow guiding region towards the lip side of the coating die head is a first preset distance, and the opening distance of the second flow guiding region towards the lip side of the coating die head is a second preset distance. The first preset distance and the second preset distance are equal or unequal; and the interval between the opening regions of the first flow guiding region and the second flow guiding region is 0.5 mm - 5.0 mm.

[0013] Preferably, in the above-mentioned coating die head, a third medium window is further formed on the first window gasket. The third medium window and the first medium window are oppositely arranged on both sides in the length direction of the second medium window, and the third medium window and the first medium window respectively coincide with a partial length region of the first medium flow channel; a third flow guiding region corresponding to the third medium window is formed on the first flow guiding gasket.

[0014] Preferably, in the above-mentioned coating die head, the first medium flow channel and the second medium flow channel are flow channels in a semi-cylindrical structure arranged in parallel.

[0015] Preferably, in the above-mentioned coating die head, a third medium flow channel is formed on the first die head, and a fourth medium flow channel is formed on the second die head; the composite gasket includes a second flow guiding gasket, and a second window gasket and a third window gasket are respectively arranged on both sides in the thickness direction of the second flow guiding gasket;

[0016] The second flow guiding gasket is provided with a fourth flow guiding area and a fifth flow guiding area at intervals. A fourth medium window is formed in the second window gasket, and the fourth medium window communicates with the third medium flow channel and the fourth flow guiding area in the thickness direction of the second window gasket. A fifth medium window is formed in the third window gasket, and the fifth medium window communicates with the fourth medium flow channel and the fifth flow guiding area in the thickness direction of the third window gasket.

[0017] Preferably, in the above coating die head, a fifth medium flow channel spaced from the third medium flow channel is further formed in the first die head. A sixth flow guiding area is formed in the second flow guiding gasket, and a sixth medium window is formed in the second window gasket. The sixth medium window communicates with the fifth medium flow channel and the sixth flow guiding area in the thickness direction of the second window gasket.

[0018] Preferably, in the above coating die head, in the length direction of the third medium flow channel, the fourth medium window and the sixth medium window are located on both sides of the fifth medium window, or the fourth medium window and the sixth medium window are adjacent and located on the same side of the fifth medium window.

[0019] Preferably, in the above coating die head, the thickness of the window gasket is 25μm - 200μm, and the thickness of the flow guiding gasket is 25μm - 200μm.

[0020] A coating machine includes the coating die head according to any one of the above embodiments.

[0021] A method for preparing a coating uses the coating machine according to the above embodiments to prepare a coating on the surface of a substrate. The preparation method at least includes the following steps:

[0022] Inspect and assemble the first die head and the second die head of the coating die head, and clamp a composite gasket between the first die head and the second die head.

[0023] Connect slurry storage tanks with two different proportioned slurries to two independent medium flow channels respectively to form two circulation loops.

[0024] Start the slurry storage tanks, so that the two slurries pass through different medium windows from two positions of the medium flow channels and reach different flow guiding areas, and form two coatings with different materials on the surface of the substrate through the lip side of the coating die head. Control the liquid discharge amounts of the two slurries respectively to make the wet film thicknesses of the two coatings on both sides the same.

[0025] Dry the coatings on both sides to form a uniform coating with two different materials and a combination or splicing of widths of the coatings together.

[0026] As can be seen from the above technical solutions, the coating die head provided by the present disclosure is specifically a structure in which a composite gasket is sandwiched between a first die head and a second die head. At the same time, at least two medium flow channels are opened on the sides of the first die head and the second die head facing each other to be able to inject slurries with different ratios into the coating die head; the composite gasket includes a window gasket and a flow guiding gasket. A medium window is opened on the window gasket, and the medium windows correspond to the medium flow channels one by one, so that each medium flow channel has a connected medium window, and the slurry flowing in the medium flow channel can reach the connected medium window. On this basis, the flow guiding area on the flow guiding gasket can receive the slurry in the medium window, and the structure of the flow guiding area is a single-sided opening structure, so that the slurry can flow out from the lip side of the coating die head and the coating can be prepared; in the above structure, the medium window is a hollow structure on the window gasket and only covers a part of the medium flow channel in the length direction of the medium flow channel, and the other areas of the medium flow channel are closed by the window gasket. The slurry can only flow out from the position of the medium window, which realizes the correspondence between different medium flow channels and medium windows, and enables different slurries to flow out at the preset medium window positions; the flow guiding areas on the flow guiding gasket are independently arranged, and each flow guiding area covers the medium window, so that the slurry flowing out at the preset medium window position flows out independently from the lip side of the coating die head through the flow guiding area without mixing, and at least two kinds of coatings of different materials are formed on the surface of the substrate during a single coating process. Moreover, the spacing between at least two kinds of coatings of different materials can be adjusted through the spacing of the flow guiding areas, and they can be spaced or connected, so as to meet the preparation requirements of complex partition coatings during a single coating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 Exploded view of the coating die head provided in an embodiment of the present disclosure;

[0029] Figure 2 For Figure 1 the flipping structure schematic diagram;

[0030] Figure 3 Schematic diagram of the structure with three medium flow channels provided on the first die head;

[0031] Figure 4 For Figure 3 the flipping structure schematic diagram;

[0032] Figure 5Explosion schematic diagram of a coating die provided by another embodiment of the present disclosure;

[0033] Figure 6 is Figure 5 Schematic diagram of the flipping structure;

[0034] Figure 7 Explosion schematic diagram of a coating die with two medium channels provided on the first die head and one medium channel provided on the second die head;

[0035] Figure 8 is Figure 7 Schematic diagram of the flipping structure.

[0036] Wherein:

[0037] 10 - First die head; 20 - Second die head;

[0038] 310 - First medium channel; 320 - Second medium channel;

[0039] 40 - First window gasket; 410 - First medium window; 420 - Second medium window;

[0040] 50 - First diversion gasket; 510 - First diversion area; 520 - Second diversion area;

[0041] 610 - Third medium channel; 620 - Fourth medium channel; 630 - Fifth medium channel;

[0042] 70 - Second diversion gasket; 710 - Fourth diversion area; 720 - Fifth diversion area; 730 - Sixth diversion area;

[0043] 80 - Second window gasket; 810 - Fourth medium window; 820 - Sixth medium window;

[0044] 90 - Third window gasket; 910 - Fifth medium window. Detailed implementation manners

[0045] The core of this application is to disclose a coating die, a coating machine, and a coating preparation method, so as to meet the preparation requirements of complex partition coatings in a single coating process through slit coating.

[0046] In order to enable those skilled in the art to better understand the solution of this application, the embodiments of this application will be described below with reference to the accompanying drawings. In addition, the embodiments shown below do not impose any limitation on the inventive content recited in the claims. Furthermore, all the contents of the configurations shown in the following embodiments are not limited to those necessary for the solution of the invention recited in the claims.

[0047] As Figure 1 and Figure 2As shown, the present disclosure provides a coating die head, which includes a first die head 10 and a second die head 20 that are opposite and spaced apart, and a composite gasket is clamped between the first die head 10 and the second die head 20 to form the main structure of the coating die head.

[0048] To meet the injection of media such as slurry, in the above structure, one or both of the first die head 10 and the second die head 20 are provided with media flow channels, and the media flow channels are arranged on the side where the first die head 10 and the second die head 20 face each other, so that the slurry medium forms a flow channel from the area between the two die heads; at the same time, at least two media flow channels are provided in the coating die head to meet the independent input of slurries with different ratios. By providing multiple media flow channels, the coating die head can process multiple media simultaneously to meet the requirements of complex processes, such as simultaneously coating conductive materials and insulating materials in the manufacture of electronic devices, or simultaneously coating matrix materials and reinforcing materials in the production of composite materials.

[0049] On this basis, the composite gasket includes at least one window gasket and at least one flow guiding gasket. It should be noted that the window gasket is used to cooperate with the media flow channel, and the number of window gaskets provided depends on the area where the first die head 10 and the second die head 20 are provided with media flow channels. For example, if only one side of the first die head 10 or only the second die head 20 is provided with a media flow channel, the window gasket is only provided on the side with the media flow channel and a single one is provided; if both the first die head 10 and the second die head 20 are provided with media flow channels, two window gaskets are provided and are respectively attached to the sides of the first die head 10 and the second die head 20 where the media flow channels are provided.

[0050] Based on the above structure, a media window corresponding to the media flow channel is provided in a hollowed-out manner on the window gasket. It should be noted that the correspondence here specifically means that each media flow channel has at least one media window, and at the same time, the media window only covers a part of the media flow channel in the length direction of the media flow channel. Here, covering means that the media window communicates with the media flow channel in the thickness direction of the window gasket. Since the media window is provided in a hollowed-out manner on the window gasket, the window gasket will block the media flow channel in the non-window area, so that in the length direction of the media flow channel, media such as slurry can only flow out from the media window area on the window gasket, and flow through the coating die head in other non-window areas and perform external circulation. At the same time, the media window only covers a part of the media flow channel in the length direction of the media flow channel, which can effectively control the flow rate and distribution of the media, make the coating process more accurate, and by adjusting the size and position of the media window, the outflow rate and outflow position of each medium can be accurately controlled, so as to meet the position distribution requirements of the coating.

[0051] Furthermore, the window gasket enables the slurry to flow into the media window at a preset position in the length direction of the coating die during the flow of the slurry in the media flow channel. On this basis, a diversion area is provided on the diversion gasket, and the diversion area is used to receive and divert the media flowing out of the media window area. Therefore, the number of diversion areas is the same as and corresponds one-to-one with the number of media windows, and several diversion areas are independently arranged to prevent different media from mixing in the diversion area and affecting the coating. Specifically, in a single set of diversion areas and media windows, the diversion area covers the media window, that is, in the thickness direction of the diversion gasket, the media window is located inside the diversion area, so that all the media flowing out of the media window can reach the inside of the diversion area. At the same time, the diversion area has a three-sided closed structure and is only open on the lip side facing the coating die. After receiving the media flowing out of the media window, the diversion area can divert the media to its open side, that is, to the lip side of the coating die to meet the coating requirements on the substrate surface.

[0052] It should be noted that for different diversion areas, they can be arranged on a single diversion gasket and partitioned through a grid structure to simultaneously form coatings on the substrate surface during the coating process; at the same time, different diversion areas can also be arranged on different diversion gaskets to generate a certain offset in the thickness direction of the diversion gasket, so that different media can form coatings on the substrate surface successively during the operation of the coating die.

[0053] The above structure can simultaneously generate coatings of at least two media during a single coating process. The generation positions of the two coatings depend on the opening positions at the bottom of the diversion area. Therefore, by adjusting the setting positions of the media window and the diversion area, the coating production positions of at least two media can also be adjusted. The coatings of different media can be arranged at preset distance intervals or spliced and combined to form a continuous wide-width coating structure to meet different production requirements. At the same time, for a single set of coating die settings, composite gaskets with different combined structures can be set, so that the coating die only needs to replace the composite gasket between the first die 10 and the second die 20 to achieve different coating preparation requirements and improve the versatility of the coating die.

[0054] Further, in some embodiments of the present disclosure, independent first and second medium channels 310 and 320 are spaced apart on the first die head 10, and the two medium channels independently convey different media. The second die head 20 has a flat plate structure to cooperate with the first die head 10 to clamp the composite gasket. Correspondingly, the composite gasket includes a first window gasket 40 and a first diversion gasket 50 arranged in a stacked manner. Among them, the first window gasket 40 is arranged on the side of the first die head 10 where the channels are opened, and the first diversion gasket 50 is arranged on the flat plate structure of the second die head 20. Correspondingly, a first medium window 410 and a second medium window 420 are opened on the first window gasket 40. Among them, the width of the first medium window 410 is not less than the width of the first medium channel 310 and coincides with a partial length area of the first medium channel 310. The medium flowing in the first medium channel 310 can flow into the first medium window 410 when passing through the first medium window 410, and is enclosed by the first window gasket 40 in other areas to achieve smooth circulation. The width of the second medium window 420 is also not less than the width of the second medium channel 320 and coincides with a partial length area of the second medium channel 320. Based on the structure of the first window gasket 40, the first medium channel 310 and the second medium channel 320 can flow into the first medium window 410 and the second medium window 420 respectively while maintaining circulation.

[0055] Correspondingly, a first diversion area 510 and a second diversion area 520 are provided on the first diversion gasket 50. Among them, the projection of the first medium window 410 in the first diversion area 510 is located within the first diversion area 510, and the projection of the second medium window 420 in the second diversion area 520 is located within the second diversion area 520. The medium in the first medium channel 310 flows into the first diversion area 510 through the first medium window 410 and is coated on the surface of the substrate through the bottom opening of the first diversion area 510. The medium in the second medium channel 320 flows into the second diversion area 520 through the second medium window 420 and is coated on the surface of the substrate through the bottom opening of the second diversion area 520. By adjusting the positions of the bottom openings of the first diversion area 510 and the second diversion area 520, the relative positions of the two different material coatings on the substrate surface can be achieved; and by adjusting the sizes of the bottom openings of the first diversion area 510 and the second diversion area 520, the different coating widths of the two different material coatings on the substrate surface can be achieved.

[0056] In a specific embodiment of the present disclosure, the opening lengths of the first diversion area 510 and the second diversion area 520 facing the lip side of the coating die are equal, so as to synchronously form two coating structures with different materials but the same width during a single operation of the coating die. In addition, it should be noted that the opening distances of the first diversion area 510 and the second diversion area 520 facing the lip side of the coating die can be independently and arbitrarily set to have a higher degree of freedom in structural setting, that is, the opening distance of the first diversion area 510 facing the lip side of the coating die is the first preset distance, and the opening distance of the second diversion area 520 facing the lip side of the coating die is the second preset distance. At the same time, the first preset distance and the second preset distance can be set to equal values, or independently set to unequal distances to meet the requirements of actual production conditions. At the same time, it should be noted that in other embodiments of the present disclosure, the opening distances of different diversion areas facing the lip side of the coating die can all be independently set to meet personalized production requirements. At the same time, it should be noted that the interval between the opening areas of the first diversion area 510 and the second diversion area 520 is 0.5 mm - 5.0 mm. Operators can, according to needs, reduce the interval between the opening areas of the first diversion area 510 and the second diversion area 520 so that the edges of the two coatings are fitted to form two connected coating structures, or can also, according to needs, increase the interval between the opening areas of the first diversion area 510 and the second diversion area 520 to form two separated coating structures on the substrate surface.

[0057] On the basis of the above embodiments, taking a specific embodiment of the present disclosure as an example for illustration:

[0058] In this embodiment, the die head length of the coating die head is 350 mm. Two semi-cylindrical flow channels, namely a first medium flow channel 310 and a second medium flow channel 320, are provided on the first die head 10, and the second die head 20 is of a flat plate structure. The first medium flow channel 310 and the second medium flow channel 320 are arranged in parallel with a parallel spacing of 5 mm, and the semi-circular diameters of both the first medium flow channel 310 and the second medium flow channel 320 are 10 mm. After the first die head 10 and the second die head 20 are clamped together, the first window gasket 40 in the composite gasket fits against the first die head 10, and the first guide gasket 50 fits against the second die head 20. At the same time, the width of the first medium window 410 provided on the first window gasket 40 is 10 mm and is aligned with the width of the first medium flow channel 310. The length of the first medium window 410 is 119 mm, and the lower edge of the first medium window 410 is 30 mm away from the outer edge of the coating side gasket; the width of the second medium window 420 provided on the first window gasket 40 is 10 mm and is aligned with the width of the second medium flow channel 320. The length of the second medium window 420 is also 119 mm, and the lower edge of the second medium window 420 is 30 mm away from the outer edge of the coating side gasket. The width of the spacer between the first medium window 410 and the second medium window 420 is 1 mm, and the thickness of the first window gasket 40 is 0.1 mm.

[0059] For the first flow guiding gasket 50, the widths of the first flow guiding area 510 and the second flow guiding area 520 it forms are 119 mm, the length from the outer edge of the gasket on the coating side is 30 mm, and the width of the spacer between the first flow guiding area 510 and the second flow guiding area 520 is 1 mm. On the basis of the above structure, the first medium flow channel 310 and the second medium flow channel 320 are respectively connected to two external pipelines to communicate with the slurry storage tank, forming two circulation paths. The two conveying systems respectively convey two different slurries. Among them, for the slurry flowing through the first medium flow channel 310, the catalyst used is 50% Pt / C (carbon-supported platinum catalyst with a platinum (Pt) loading of 50% (mass fraction)), the IEC (ion exchange capacity) value of the resin is 1.1, and the I / C ratio (the ratio of resin to catalyst in the catalyst slurry) is 0.95; the solid content of the slurry is 8.0%, and the viscosity range of the slurry is 100 cP; for the slurry flowing through the second medium flow channel 320, the catalyst used is 50% Pt / C, the IEC value of the resin is 1.1, and the I / C ratio is 0.75; the solid content of the slurry is 8.0%, and the viscosity range of the slurry is 80 cP. During the production of the coating die head, the two slurries are respectively introduced into the first medium flow channel 310 and the second medium flow channel 320 through pipelines. Through the selective action of the first medium window 410 and the second medium window 420 on the first window gasket 40, they respectively enter the first flow guiding area 510 and the second flow guiding area 520 on the first flow guiding gasket 50, respectively controlling the liquid discharge amounts of the two slurries to achieve the same wet film thickness on both sides of the coating. The two slurries are simultaneously coated on a proton exchange membrane type substrate. After drying, a uniform coating formed by splicing two 120-mm-wide coatings together can be obtained, completing the preparation of the CCM (catalyst coated membrane) part with a partitioned structure for fuel cell components. It should be noted that according to the formulation characteristics of the two slurries, the setting positions of the first flow guiding area 510 and the second flow guiding area 520 are adjusted so that the coating with a high I / C ratio is used on the cathode non-humidifying or low-humidifying inlet side to maintain proton fluidity under low humidity conditions; while the coating with a low I / C ratio is used on the cathode outlet side to quickly discharge the product water.

[0060] It should be further noted that, in some other embodiments of the present disclosure, it is necessary to set a coating in the form of A-B-A on the surface of the substrate. Based on the above structure, the present disclosure can also open a third medium window on the first window gasket 40, and the third medium window and the first medium window 410 are oppositely arranged on both sides of the second medium window 420 in its length direction. Based on the structure in which the first medium window 410 and the second medium window 420 respectively correspond to the first medium flow channel 310 and the second medium flow channel 320, the third medium window and the first medium window 410 respectively overlap with partial length regions of the first medium flow channel 310, so that during the process of the medium flowing in the first medium flow channel 310, it will flow into the alternately arranged first medium window 410 and third medium window. Correspondingly, a third diversion area corresponding to the third medium window is opened on the first diversion gasket 50. The medium flowing into the third medium window will enter the third diversion area and flow out from the bottom of the third diversion area. Thus, in this embodiment, during a single coating process, the second medium window 420 located in the middle position will pass through the second diversion area 520, so that the first medium forms a coating on the surface of the substrate, while the first medium window 410 and the third medium window on both sides of the second medium window 420 will pass through the first diversion area 510 and the third diversion area, so that the second medium forms two coatings on the surface of the substrate. Combining with the first medium, the effect of forming a coating in the form of A-B-A on the surface of the substrate is achieved, meeting the production requirements.

[0061] In addition, as Figure 3 and Figure 4 shown, more medium flow channels can also be opened on the first die head 10 to cooperate with the medium windows of the first window gasket 40 and the diversion areas of the first diversion gasket 50, so as to meet the coating requirements of more material media on the surface of the substrate.

[0062] Furthermore, in some other embodiments of the present disclosure, different from the form in which the second die head 20 is a flat structure in the foregoing embodiments, as Figure 5 and Figure 6 shown, medium flow channels are opened on both the first die head 10 and the second die head 20. Specifically, a third medium flow channel 610 is opened on the first die head 10, and a fourth medium flow channel 620 is opened on the second die head 20. The third medium flow channel 610 and the fourth medium flow channel 620 are located in different thickness regions on the coating die head and are oppositely arranged, providing paths for two different proportioned media. Correspondingly, the composite gasket includes a second diversion gasket 70 and two window gaskets, that is, a second window gasket 80 and a third window gasket 90 respectively arranged on both sides in the thickness direction of the second diversion gasket 70. Correspondingly, fourth diversion areas 710 and fifth diversion areas 720 are arranged at intervals on the second diversion gasket 70.

[0063] To meet the separation and diversion requirements for two media, a fourth medium window 810 is provided on the second window gasket 80. At the same time, in the thickness direction of the second window gasket 80, the fourth medium window 810 communicates with the third medium flow channel 610 and the fourth diversion area 710. The medium passing through the third medium flow channel 610 will pass through the fourth medium window 810 on the second window gasket 80 and reach the fourth diversion area 710 to flow out from the bottom of the fourth diversion area 710 to form a coating. And a fifth medium window 910 is provided on the third window gasket 90. Similarly, the fifth medium window 910 communicates with the fourth medium flow channel 620 and the fifth diversion area 720 in the thickness direction of the third window gasket 90, so that the medium passing through the fourth medium flow channel 620 can reach the fifth diversion area 720 through the fifth medium window 910 and flow out from the bottom of the fifth diversion area 720 to form a coating. Different from the foregoing embodiments, in this embodiment, medium flow channels are respectively provided on the first die head 10 and the second die head 20, and then diversion is realized through the window gaskets on both sides, and the medium passage is transmitted to the second diversion gasket 70 in the middle area, and then coatings of different materials and areas are formed on the substrate surface through the fourth diversion area 710 and the fifth diversion area 720.

[0064] Based on the structure of the above embodiments, a specific embodiment of the present disclosure will be described for illustration. Specifically, in this embodiment: the die head length of the coating die head is 400 mm, and a third medium flow channel 610 with a semi-cylindrical cavity structure is provided on the first die head 10, while a fourth medium flow channel 620 with a semi-cylindrical cavity structure is provided on the second die head 20. After the coating die head is assembled by clamping, the third medium flow channel 610 and the fourth medium flow channel 620 are arranged in parallel, and the parallel spacing is 5 mm. The composite gasket disposed between the first die head 10 and the second die head 20 includes a second flow guiding gasket 70 disposed in the middle, and a second window gasket 80 and a third window gasket 90 disposed on both sides of the second flow guiding gasket 70 in the thickness direction of the second flow guiding gasket 70. At the same time, the diameter of the semi-cylindrical structure of the third medium flow channel 610 disposed on the first die head 10 is 10 mm, and the fourth medium window 810 opened on the corresponding second window gasket 80 has the same width of 10 mm and is aligned with the third medium flow channel 610 in the width direction. It should be noted that the length of the fourth medium window 810 is 159 mm. The diameter of the semi-cylindrical structure of the fourth medium flow channel 620 disposed on the second die head 20 is 10 mm, and the fifth medium window 910 opened on the corresponding third window gasket 90 has the same width of 10 mm and is aligned with the fourth medium flow channel 620 in the width direction. The length of the fifth medium window 910 is 139 mm. For the second flow guiding gasket 70 disposed in the middle position, a fourth flow guiding area 710 and a fifth flow guiding area 720 are provided. Among them, the fourth flow guiding area 710 corresponds to the fourth medium window 810, and the opening length of the fourth flow guiding area 710 is 159 mm, and the length from the outer edge of the coating side gasket is 30 mm; while the fifth flow guiding area 720 corresponds to the fifth medium window 910, and the opening length of the fifth flow guiding area 720 is 139 mm, and the length from the outer edge of the coating side gasket is 40 mm. In addition, the interval between the fourth flow guiding area 710 and the fifth flow guiding area 720 disposed on the second flow guiding gasket 70 is 1 mm.

[0065] Based on this structure, the third medium flow channel 610 and the fourth medium flow channel 620 are respectively connected to two external pipelines to form two circulation paths with the slurry storage tank. The two conveying systems respectively convey two different slurries. Among them, the slurry passing through the third medium flow channel 610 has a composition of 10% carbon powder, 14% Triton (copolyester material), 4% PTFE (polytetrafluoroethylene) resin, and 0.2% CMC (sodium carboxymethyl cellulose). The solid content of the slurry is 28.2%, and the viscosity range of the slurry is 400 cP. The slurry passing through the fourth medium flow channel 620 has a composition of 10% carbon powder, 13% Triton, 8% PTFE resin, and 0.2% CMC (sodium carboxymethyl cellulose). The solid content of the slurry is 28.2%, and the viscosity range of the slurry is 400 cP. During the production of the coating die head, the two slurries are respectively introduced into the third medium flow channel 610 and the fourth medium flow channel 620 through pipelines. Through the selection function of the window gasket, they respectively enter the fourth diversion area 710 and the fifth diversion area 720 on the second diversion gasket 70, and respectively control the liquid output of the two slurries to achieve the same wet film thickness on both sides of the coating. The two slurries are simultaneously coated on a carbon paper type substrate. After drying, a uniform coating formed by splicing two coatings of 160 mm and 140 mm can be formed. Then, through high-temperature heat treatment in a muffle furnace at 350 °C for 1 h, the preparation of the gas diffusion layer with a partitioned structure for fuel cell components is completed. At the same time, according to the characteristics of the MPL (microporous layer) slurry, it is divided into two coatings with different PTFE contents. The coating with a low PTFE content is used on the non-humidifying or low-humidifying inlet side of the cathode to maintain the CCM water content under low humidity conditions and improve the conductivity of the GDL (gas diffusion layer). The coating with a high PTFE content is used on the cathode outlet side to quickly discharge the product water.

[0066] It should be noted that for the third medium flow channel 610 opened on the first die head 10 and the fourth medium flow channel 620 opened on the second die head 20, two spaced-apart medium windows can also be opened on the window gasket for the medium flow channel, and two diversion areas can be correspondingly opened on the diversion gasket, so that a single medium can form two spaced-apart coatings on the substrate surface. Combining with another medium, an A - B - A form coating structure is formed. The method of forming the A - B - A form coating is the same as that in the previous embodiment, and will not be elaborated here.

[0067] To further optimize the above technical solution and achieve the coating setting of three different media on the same substrate surface, in some embodiments of the present disclosure, based on the above structure, such as Figure 7 and Figure 8As shown, a fifth medium flow channel 630 is also provided on the first die head 10. The fifth medium flow channel 630 is arranged at an interval from the third medium flow channel 610 to provide a flow channel for another group of media. Correspondingly, a sixth diversion area 730 is provided on the second diversion gasket 70, and a sixth medium window 820 is provided on the second window gasket 80. The sixth medium window 820 communicates the fifth medium flow channel 630 and the sixth diversion area 730 in the thickness direction of the second window gasket 80. After the coating die head is closed, three independent flow channels are formed inside it, and it can be externally connected to a slurry storage tank to form three circulation paths, so that three different material coating structures can be produced on the surface of the substrate during a single production process.

[0068] It should be noted that the above embodiment is only described by taking the example of arranging two medium flow channels on the first die head 10. In some other embodiments of the present disclosure, two or more medium flow channels can also be provided on the second die head 20 to realize the flow of different amounts of media, so as to form coatings of various materials. The setting structure is similar to that of the foregoing embodiment and will not be elaborated here.

[0069] It should be further noted that since the fourth medium window 810 and the sixth medium window 820 are provided on the second window gasket 80, they need to divert two different medium flow channels on the first die head 10, namely the third medium flow channel 610 and the fifth medium flow channel 630. In the length direction of the third medium flow channel 610, the fourth medium window 810 and the sixth medium window 820 can be arranged on both sides of the fifth medium window 910, so that the fourth medium window 810 and the sixth medium window 820 have a large interval on the second window gasket 80. Similarly, in the length direction of the third medium flow channel 610, the fourth medium window 810 and the sixth medium window 820 can also be arranged adjacent to each other to have a small interval, and both are located on the same side of the fifth medium window 910.

[0070] Based on the structure of the above embodiments, taking a specific embodiment of the present disclosure as an example for illustration. In this embodiment, coatings of three different media need to be formed on the surface of the substrate. Specifically, in this embodiment, the length of the coating die head is 400 mm. A third medium flow channel 610 and a fifth medium flow channel 630 with a semi-cylindrical structure are provided on the first die head 10. The two flow channels are arranged in parallel with a spacing of 5 mm. And a fourth medium flow channel 620 with a semi-cylindrical structure is provided on the second die head 20. After the first die head 10 and the second die head 20 are closed, the medium flow channels on the two die heads are in an interleaved form. At the same time, the semi-circular diameters of the third medium flow channel 610 and the fifth medium flow channel 630 on the first die head 10 are both 10 mm. On the second window gasket 80 corresponding to the first die head 10, the widths of the fourth medium window 810 and the sixth medium window 820 opened are both 10 mm, and they are aligned with the corresponding medium flow channels in the width direction. At the same time, the lengths of the fourth medium window 810 and the sixth medium window 820 are both 99 mm. On the third window gasket 90 corresponding to the second die head 20, a fifth medium window 910 is opened to communicate with the fourth medium flow channel 620, and the length of the fifth medium window 910 is 99 mm. Based on the number of medium flow channels on the first die head 10 and the second die head 20, a fourth diversion area 710, a fifth diversion area 720, and a sixth diversion area 730 are provided on the second diversion gasket 70 to correspond to the three medium windows one by one. The opening length of the fourth diversion area 710 is 99 mm, and the distance from the outer edge of the coating side gasket is 30 mm; the opening length of the fifth diversion area 720 is 99 mm, and the distance from the outer edge of the coating side gasket is 30 mm; the opening length of the sixth diversion area 730 is 100 mm, and the distance from the outer edge of the coating side gasket is 40 mm; the interval widths of the three diversion areas are all 1 mm.

[0071] On this basis, the third medium flow channel 610, the fourth medium flow channel 620, and the fifth medium flow channel 630 are respectively connected to three external pipelines to form three circulation paths with a slurry storage tank. The three conveying systems respectively convey three different slurries. Among them, the slurry conveyed in the third medium flow channel 610 has a composition of 10% carbon powder, 14% Triton, 4% PTFE resin, and 0.2% CMC. The solid content of the slurry is 28.2%, and the viscosity range of the slurry is 400 cP; while the slurry conveyed in the fourth medium flow channel 620 has a composition of 10% carbon powder, 13% Triton, 8% PTFE resin, and 0.2% CMC. The solid content of the slurry is 31.2%, and the viscosity range of the slurry is 450 cP; while the slurry conveyed in the fifth medium flow channel 630 has a composition of 7% carbon powder, 4% Triton, 3% PTFE resin, 0.3% CMC, and 3.5% ammonium oxalate. The solid content of the slurry is 30%, and the viscosity range is 500 cP. The three slurries with different ratios are respectively introduced into the third medium flow channel, the fourth medium flow channel 620, and the fifth medium flow channel 630 of the two die heads of the coating head through pipelines. After reaching the fourth diversion area 710, the fifth diversion area 720, and the sixth diversion area 730 on the second diversion gasket 70, they are simultaneously coated on a carbon paper type substrate. After drying, a uniform coating with widths of 100 mm, 100 mm, and 100 mm spliced together is formed. Then, through high-temperature heat treatment in a muffle furnace at 350 degrees for 1 hour, the preparation of the gas diffusion layer with a partitioned structure for fuel cell components is completed.

[0072] In addition, it should be noted that in the coating die head provided in the embodiment of the present disclosure, the thickness of the window gasket is 25 μm - 200 μm, and the thickness of the diversion gasket is also 25 μm - 200 μm to provide a uniform flow channel for the medium.

[0073] Furthermore, the embodiment of the present disclosure also provides a coating machine, which includes the coating die head provided in any one of the above embodiments. It should be noted that since the coating die head has the technical effects provided in any one of the above embodiments, this coating machine also has the technical effects provided in any one of the above embodiments, which will not be elaborated herein again.

[0074] Furthermore, the embodiment of the present disclosure also provides a coating preparation method for using the above coating machine to prepare a coating on the surface of a substrate. Specifically, the preparation method at least includes the following steps:

[0075] S01: Inspect and assemble the first die head 10 and the second die head 20 of the coating die head, and clamp a composite gasket between the first die head 10 and the second die head 20;

[0076] S02: Connect the slurry storage tanks with two different slurry ratios to two independent medium flow channels respectively to form two circulation loops.

[0077] S03: Start the slurry storage tanks, so that the two slurries pass through different medium windows from the positions of the two medium flow channels and reach different diversion areas, and form two coatings with different materials on the surface of the substrate through the lip side of the coating die. Control the liquid discharge amounts of the two slurries respectively to make the wet film thicknesses of the two side coatings the same.

[0078] S04: Dry the two side coatings and form a uniform coating with a combination or splicing of two coatings with different materials and widths.

[0079] It should be noted that for coating machines with more medium flow channels, the coating method is the same as the above steps, and the only difference lies in the change in the number of slurry storage tanks, which will not be elaborated here.

[0080] The terms "first", "second", "left side" and "right side" in the description, claims and above-mentioned drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may include unlisted steps or units.

[0081] The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coating die head, characterized in that: include: A first die head and a second die head are arranged opposite to each other and spaced apart, and at least two medium flow channels are provided on two walls facing each other of the first die head and the second die head; A composite gasket, clamped between the first die head and the second die head, the composite gasket comprising at least one window gasket and at least one guide gasket; The window gasket is arranged on a side of the first die head and the second die head where the medium flow channel is opened, and a medium window corresponding to the medium flow channel is hollowed out on the window gasket, and the medium window only covers a partial area of ​​the medium flow channel in the length direction of the medium flow channel; a guide area is opened on the guide gasket, and the number of the guide areas is the same as that of the medium windows, and several guide areas are independently arranged; in a single group of the guide area and the medium window, the guide area covers the medium window, and the lip side of the guide area facing the coating die head is an open structure.

2. The coating die head according to claim 1, characterized in that The first die head is provided with an independent first medium flow channel and a second medium flow channel at intervals, and the second die head is a flat plate structure; The composite gasket includes a first window gasket and a first guide gasket which are stacked, the first window gasket is arranged in contact with the first die head, and a first medium window and a second medium window are provided on the first window gasket, the width of the first medium window is not less than the width of the first medium flow channel, and overlaps with a partial length area of ​​the first medium flow channel; the width of the second medium window is not less than the width of the second medium flow channel, and overlaps with a partial length area of ​​the second medium flow channel; the first guide gasket is provided with a first guide area and a second guide area, the projection of the first medium window on the first guide area is located in the first guide area, and the projection of the second medium window on the second guide area is located in the second guide area.

3. The coating die head according to claim 2, characterized in that The opening distance of the first guide area toward the lip side of the coating die is a first preset distance, and the opening distance of the second guide area toward the lip side of the coating die is a second preset distance. The first preset distance is equal to or different from the second preset distance; and the interval between the opening areas of the first guide area and the second guide area is 0.5mm-5.0mm.

4. The coating die head according to claim 2, characterized in that A third medium window is also provided on the first window gasket, and the third medium window and the first medium window are arranged on both sides of the second medium window in the length direction opposite to each other, and the third medium window and the first medium window respectively overlap with partial length areas of the first medium flow channel; a third guide area corresponding to the third medium window is provided on the first guide gasket.

5. The coating die head according to claim 2, characterized in that, The first medium flow channel and the second medium flow channel are flow channels of a semi-cylindrical structure arranged in parallel.

6. The coating die head according to claim 1, characterized in that The first die head is provided with a third medium flow channel, and the second die head is provided with a fourth medium flow channel; the composite gasket comprises a second flow guide gasket, and a second window gasket and a third window gasket respectively provided on both sides of the second flow guide gasket in a thickness direction; The second guide gasket is provided with a fourth guide area and a fifth guide area at intervals, the second window gasket is provided with a fourth medium window, and the fourth medium window connects the third medium flow channel and the fourth guide area in the thickness direction of the second window gasket; the third window gasket is provided with a fifth medium window, and the fifth medium window connects the fourth medium flow channel and the fifth guide area in the thickness direction of the third window gasket.

7. The coating die head according to claim 6, characterized in that A fifth medium flow channel spaced apart from the third medium flow channel is also provided on the first die head, a sixth flow guide area is provided on the second flow guide gasket, a sixth medium window is provided on the second window gasket, and the sixth medium window connects the fifth medium flow channel and the sixth flow guide area in the thickness direction of the second window gasket.

8. The coating die head according to claim 7, characterized in that In the length direction of the third medium flow channel, the fourth medium window and the sixth medium window are located on both sides of the fifth medium window, or the fourth medium window and the sixth medium window are arranged adjacent to each other and are located on the same side of the fifth medium window.

9. The coating die head according to claim 1, characterized in that: The thickness of the window gasket is 25 μm-200 μm, and the thickness of the guide gasket is 25 μm-200 μm.

10. A coating machine, characterized in that: The coating die comprises a coating die as described in any one of claims 1 to 9.

11. A coating preparation method, characterized in that: A coating is prepared on the surface of a substrate using the coating machine as claimed in claim 10, wherein the preparation method comprises at least the following steps: Inspect and assemble the first die head and the second die head of the coating die head, and clamp the composite gasket between the first die head and the second die head; The slurry storage tanks with two slurries of different proportions are respectively connected to two independent medium flow channels to form two circulation loops; Start the slurry storage tank, so that the two slurries pass through different medium windows from two medium flow channel positions and reach different diversion areas, and form two coatings of different materials on the surface of the substrate through the lip side of the coating die head. Control the liquid output of the two slurries respectively so that the coatings on both sides have the same wet film thickness; Dry the coating on both sides and form a uniform coating with two different materials and width coating combinations or splices.

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