Method for simultaneously coating at least two polymeric functional materials onto a substrate

Abstract

This invention relates to a method for simultaneously coating at least two polymeric materials (12, 14) onto a substrate (10) held in a stationary position (16) or moving in a feed direction (66). The method involves the following steps: coating a first polymeric functional material (12) onto at least a first coating surface (28, 30) of the substrate using at least one coating element (22, 26, 60, 62). Subsequently, a second polymeric functional material (14) is coated onto a third coating surface (32) surrounded by or adjacent to the at least two coating surfaces (28, 30) using at least one coating element (24, 60, 62). The invention also relates to the application of a method for coating at least two polymeric functional materials (12, 14) onto a monopolar or bipolar plate by screen printing or stencil printing.

Description

Technical Field

[0001] This invention relates to a method for simultaneously coating at least two polymeric functional materials onto a substrate, wherein the substrate is held in a stationary position or moves along a feed direction. Furthermore, this invention relates to applications of methods for coating at least two polymeric functional materials onto a monopolar or bipolar plate by screen printing or stencil printing, and to applications of applying at least two polymeric functional materials onto a monopolar or bipolar plate using a coating roller. Background Technology

[0002] To achieve sufficient electrical efficiency in fuel cells, which are increasingly important in the framework of electric mobility, individual fuel cells are stacked on top of each other. The resulting stack is also known as a fuel cell stack. Following common manufacturing methods, for the stack construction, adhesive seals are printed onto bipolar plates using screen printing. A coating material is applied to the flow field on the active side of the bipolar plates, for example, by a rolling process. The disadvantage of this process is that coating two polymer functional materials onto the substrate using two methods, namely screen printing and rolling, requires at least two process steps. Additional process steps are needed if the curing process of both materials needs to be considered. Coating two polymer functional materials onto the substrate according to the above method requires a long cycle time, making it generally not possible to manufacture stacks or fuel cell stacks quickly. This results in high production costs because two additional methods must be used.

[0003] Furthermore, screen printing or stencil printing for standard applications presents the following drawbacks: the print quality of materials printed using screen printing or stencil printing depends on numerous influencing factors, such as printing speed (round-trip speed), separation speed, the rheological properties of the material to be coated, the characteristics of the filler material in terms of particle size and particle size distribution, squeegee material, squeegee angle, stencil material, stencil mesh structure, to name just a few. A change in any of these exemplary parameters can drastically affect print quality. This, in turn, leads to significant fluctuations in manufacturing quality. In short, it is a process classified as unstable.

[0004] Furthermore, it should be emphasized that standard screen printing and / or stencil printing typically only allows one material to be printed onto the substrate. There is no possibility of applying two materials to the substrate simultaneously. Summary of the Invention

[0005] Following the solution according to the invention, a method is proposed for simultaneously coating at least two polymer functional materials onto a substrate, the substrate being held in a stationary position or moving along a feed direction, wherein at least the following method steps are performed: a) Applying a first polymeric functional material to at least a first coating surface of the substrate using at least one coating element. b) Apply the second polymeric functional material to an intermediate coating surface that is surrounded by or adjacent to the at least first coating surface using at least one additional coating element.

[0006] Therefore, the solution proposed according to the present invention allows for the simultaneous coating of two polymer functional materials, which significantly reduces the required cycle time.

[0007] In an advantageous extension of the method proposed according to the invention, a sealing adhesive is applied as a first polymer functional material according to step a).

[0008] In another advantageous extension of the method proposed according to the invention, a conductive adhesive is applied as a second polymer functional material according to step b).

[0009] Finally, in another advantageous embodiment of the method proposed according to the invention, according to method step a), the first coating surface is moved by the first and third coating elements in the first or second feed direction.

[0010] Furthermore, following the method proposed according to the present invention, according to method step b), the third coating surface is moved past by the second coating element.

[0011] In the method proposed according to the invention, all coating elements move above a screen or template. According to a second aspect of the method proposed according to the invention, steps a) and b) are performed by a first coating roller on the first active side of the substrate.

[0012] Further following the method proposed according to the invention, method steps a) and b) are performed by first and second coating rollers on the first and second sides of the substrate.

[0013] In an advantageous extension of the method proposed according to the invention, the first and second polymeric functional materials are removed from a material container, in which they are separated from each other by a spatial separator. This allows distinct regions of the roll shells of the first and second coating rollers to be wetted by only one of the first and second polymeric functional materials.

[0014] In the method proposed according to the present invention, a first polymeric functional material and a second polymeric functional material are further removed from a material container, wherein the first polymeric functional material and the second polymeric functional material are separated from each other by a spacer.

[0015] In another advantageous embodiment of the method according to the invention, the first polymer functional material and the second polymer functional material are respectively fed onto the first coating roller and / or the second coating roller via an intermediate roller. Thus, a uniform coating thickness can be achieved due to the splitting process in the roll gap between the intermediate roller and the respective first and second coating rollers.

[0016] Advantageously, a first adhesive profile or a second adhesive profile can be applied on a first side of the substrate (especially in the case of a coating used to manufacture a multi-pole plate) by means of the method proposed according to the invention.

[0017] Furthermore, instead of the previous process, in the method proposed according to the present invention, when manufacturing a bipolar plate, a first adhesive profile and / or a second adhesive profile may be applied on the first active side and the second active side of the substrate.

[0018] In the case of manufacturing a monopolar plate, the first bonding profile or the second bonding profile can be formed on the first active side of the substrate, wherein, in this case, a cooling side is formed on the back side of the active side of the substrate.

[0019] Furthermore, the present invention relates to the application of the above-described method for manufacturing monopolar or bipolar plates by screen printing or stencil printing at least two polymeric functional materials. Additionally, the method proposed according to the present invention can be used to manufacture monopolar or bipolar plates, wherein at least two polymeric functional materials are coated onto a substrate via a coating roller.

[0020] Advantages of the invention According to the method proposed in this invention, and according to a first aspect of the invention, two polymer functional materials can be simultaneously coated onto different locations on a substrate using screen printing and stencil printing with at least two squeegee-shaped coating elements. This significantly reduces the cycle time for manufacturing or coating the substrate. In particular, different layer thicknesses of the two polymer functional materials to be coated can be achieved by adjusting the stencil thickness using screen printing and stencil printing.

[0021] Using screen printing and stencil printing, adhesive sealant can be applied to the edges of, for example, a monopolar plate to seal the monopolar plate, and by applying conductive adhesive to the web of the flow field, the gas diffusion layer can be fixed, bonded, or electrically contacted on the MEA.

[0022] According to a second aspect of the solution proposed according to the invention, by means of a roll forming method, using the first and second coating rollers and intervening with an intermediate roller, rapid coating of a relatively large application area on the substrate (whether on the first active side or the second active side) can be achieved. It is possible to very quickly and simultaneously coat two different materials (in the present case, a first polymer functional material and the polymer functional material) onto different regions of the substrate on both sides. Therefore, for example, in the manufacture of monopole and bipole plates for fuel cell stacks, a significant reduction in cycle time for constructing the stack or pile can be achieved. Using only one method and one process step instead of multiple methods and multiple process steps results in an overall reduction in production costs and an increase in cycle time.

[0023] Compared to screen printing and stencil printing, the use of coating rollers is characterized by the fact that coating via a rotating roller shell depends on relatively few process parameters, thus enabling a stable coating process.

[0024] The method proposed according to the present invention enables continuous fuel cell stack manufacturing without interruption of manufacturing steps, thereby achieving high-volume production. Furthermore, the method proposed according to the present invention can significantly reduce manufacturing costs, as only one device is needed for both processes. In addition, very high product quality and reproducibility can be achieved, with a substantial reduction in scrap rates. Attached Figure Description

[0025] Embodiments of the invention will be further explained with the aid of the accompanying drawings and the following description.

[0026] It shows: Figure 1 In screen printing and stencil printing, two polymer functional materials are simultaneously coated onto various locations on a substrate (especially a bipolar plate) using two squeegee-like coating elements. Figure 2 Using screen printing and stencil printing, two polymer functional materials are simultaneously coated onto different locations on a substrate using three doctor blade-shaped coating elements. Figure 3.1 , 3.2 Various implementations and variations of the coating roller structure, Figure 4 : A side view of a coating unit with coating rollers, used to apply polymer functional materials to the active and cooled sides of a substrate. Figure 5 A variant of the coating unit with a coating roller for applying polymeric functional materials to both active sides. Figure 6 :according to Figure 5 A side view of the coating unit. Figure 7.1 , 7.2 For example, the adhesive profile applied to monopolar and bipolar plates, and Figure 8.1 , 8.2 : A top view of a material container in which first and second polymer functional materials are stored spatially separate from each other. Detailed Implementation

[0027] In the following description of embodiments of the invention, the same or similar elements are indicated by the same reference numerals, wherein repeated descriptions of these elements are omitted in individual cases. The accompanying drawings are for illustrative purposes only, showing the subject matter of the invention.

[0028] Figure 1 The invention illustrates how, according to a first aspect, two polymeric functional materials are simultaneously coated onto various locations on a substrate (particularly a bipolar plate) using two doctor blade-like coating elements in screen printing and stencil printing.

[0029] Figure 1 As shown, a substrate 10 (e.g., the base material for a bipolar plate or monopolar plate to be manufactured) is covered on its first side 18 by a screen or template 44. The screen or template 44 includes different coating areas. Figure 1 The illustration shows substrate 10 in a rest position 16. A first side 18 of substrate 10 is covered by the screen or template 44. It comprises at least two parts, wherein a first part is located above the flow field 42 (especially as a monopole or bipole of substrate 10), while another part extends around the flow field and defines an edge region extending laterally and longitudinally.

[0030] according to Figure 1 As illustrated, the first polymer functional material 12 is applied by a first scraper-shaped coating element 22, for example, in the first feed direction 36. This can be done in a similar manner on the opposing edges of the screen or template 44.

[0031] The first coating surface 28 extends in the transverse direction relative to the screen 44 or template 44, and the second coating surface 30 extends in the longitudinal direction relative to the third coating surface 32 which is pre-defined by the flow field 42 and extends substantially centrally.

[0032] from Figure 1 and 2 The results show that by simultaneously coating two polymer functional materials 12 and 14 onto different coating surfaces 28, 30, and 32, it is possible to achieve the desired effect based on the following: Figure 1 The coating is applied above the flow field 42 using a first scraper-shaped coating element 22 and a second scraper-shaped coating element 24, or it can be based on... Figure 2Two polymer functional materials 12 and 14 were simultaneously coated onto different coating surfaces 28, 30, and 32 using three scraper-shaped coating elements 22, 24, and 26. Figure 1 and 2 In the implementation scenario of the method proposed according to the present invention, the different layer thicknesses of the two polymer functional materials 12, 14 used can be set by adjusting the corresponding areas on the screen 44 or template 44.

[0033] according to Figure 1 In one implementation variant, the two scraper-shaped coating elements 22, 24 can move simultaneously and undisturbed along their designed paths via corresponding controllers. This also applies to the second scraper-shaped coating element 24.

[0034] According to Figure 1 and 2 Of the two polymer functional materials 12 and 14 coated by the doctor blade-shaped coating elements 22, 24, and 26, the first polymer functional material 12 can be an adhesive sealant, and the second polymer functional material 14 can be a conductive adhesive. In particular, it is applied over the flow field 42 of the substrate 10 (e.g., a bipolar plate) by means of the second coating element 24.

[0035] according to Figure 3.1 and 3.2 The second aspect of the solution proposed according to the present invention will be explained in more detail.

[0036] from Figure 3.1 and 3.2 The illustration shows the differently structured roller shell 58 of the coating rollers 60, 62, which are not shown in detail here (see illustrations). Figure 4 (Illustration). According to in Figure 3.1 The variant shown extends the described third coating surface 32 on the roll structure shown here on the envelope surface 58. This third coating surface is defined by two coating surfaces 30 on the edge side.

[0037] Figure 3.2 It shows according to Figure 3.1 A modification of the roller structure, in which the coating surface 32, which extends substantially centrally, is bounded at both edges by a second coating surface 30, is implemented in this variant of the roller structure of roller shell 58. Figure 3.2 In the embodiment shown, the centrally extending third coating surface 32 is interrupted at the first coating surface 28, which extends in the transverse direction on the roller shell 58.

[0038] According to Figure 3.1 Implementation variants, utilizing in Figure 3.1 and 3.2The roller shell 58 configured in the middle is capable of coating a first polymer functional material 12 (preferably a sealing adhesive) on both sides (i.e., the two coating surfaces 30 in the longitudinal direction) and coating a second polymer functional material 14 (conductive adhesive) on a third coating surface 32 that extends continuously in the center.

[0039] According to Figure 3.2 In one embodiment, the third coating surface 32 may be coated with a first polymeric functional material 12 (especially a sealing adhesive) around its edges, and a second polymeric functional material 14 in the form of a conductive adhesive may be coated within the centrally extending third coating surface 32, but according to... Figure 3.1 In different implementation variants, the second polymer functional material is not continuously extended.

[0040] Figure 4 A side view of the coating unit is shown as a schematic illustration.

[0041] Unlike the first aspect of the invention, in which the substrate 10 is held in the rest position 16, the substrate 10 is conveyed in the feed direction 66. Figure 4 In some variations, a monopolar plate having a first active side 52 and a cooling side 56 is fabricated from substrate 10. The cooling side 56 and the first active side 52 of substrate 10 are coated continuously or discontinuously via a first coating roller 60 or a second coating roller 62. The roller shells 58 of the first coating roller 60 and the second coating roller 62 may have, according to... Figure 3.1 and 3.2 The roller structure. Each of the two coating rollers 60, 62 is in line contact with an intermediate roller 64. This intermediate roller 64 is immersed, for example, in a material container 72 configured as a trough 76, on the immersion side or conveying side 78. In the material container 72 configured as a trough 76, a first polymeric functional material 12 and a second polymeric functional material 14 are separated from each other by a spacer 74. The first polymeric functional material 12 is preferably a sealing adhesive, and the second polymeric functional material 14 is preferably a conductive adhesive. Due to the spacer 74 within the material container 72, the polymeric functional materials 12, 14 do not mix with each other, but instead remain separated.

[0042] The first polymer functional material 12 and the second polymer functional material 14 are transferred in membrane form to the material container 72 via an intermediate roller 64 immersed in the material container 72 on the immersion side 78. Figure 3.1 and 3.2 On the structured roller shell 58. Through them, due to the regional wetting of the roller shell 58, the polymer functional materials 12, 14 can be transferred to the first active side 52 of the substrate 10 conveyed in the feed direction 66.

[0043] In the case where the monopolar plate is fabricated from the substrate 10, the cooling side 56 remains uncoated, while the first active side 52 corresponds to the coating according to... Figure 3.1 and 3.2 The roller structure is coated with either the first polymer functional material 12 or the second polymer functional material 14.

[0044] from Figure 5 As can be seen, in the case of manufacturing a bipolar plate from a substrate 10 conveyed along the feed direction 66, both the first active side 52 and the second active side 54 are coated via the first coating roller 60 and the second coating roller 62. In this case, on the front and back sides of the substrate 10 conveyed along the feed direction 66, as shown in... Figure 3.1 and 3.2 As shown, corresponding to the roller structure of the roller shell 58, the first polymer functional material 12 and the second polymer functional material 14 are coated onto the first active side 52 and the second active side 54 of the substrate 10. Similar to... Figure 4 As shown in the diagram, the first polymer functional material 12 and the second polymer functional material 14 are separated from each other in the material container 72 by a space separator 74, so that the mixing of polymer functional materials 12 and 14 does not occur.

[0045] Similar to according to Figure 4 As illustrated, the intermediate roller 64, which is immersed in the material container 72 on the immersion side or conveying side 78, can rotate in a first rotation direction 68 corresponding to the clockwise direction, or it can rotate in a second rotation direction 70 corresponding to the counterclockwise direction. The same applies to the first and second coating rollers 60, 62, which can rotate in both the first rotation direction 68 (clockwise) and the second rotation direction 70 (counterclockwise).

[0046] from Figure 6 It can be seen in Figure 4 and 5 The side view of the coating unit is shown schematically.

[0047] according to Figure 6 As shown in the illustration, substrate 10 is coated with the first polymer functional material 12 in its edge region and with the second polymer functional material 14 in its central region. This is due to the space separator 74 within the material container 72 and the intermediate roller 64 (e.g., according to...). Figure 6 The correspondingly structured roller shell 58 of the second coating roller 62 generates the coating pattern on the substrate 10 conveyed along the feed direction 66.

[0048] from Figure 7.1 and 7.2 Different adhesive contours 80 and 82 can be seen in the images.

[0049] When in Figure 7.1 When the first adhesive contour 80 shown is coated with a first polymeric functional material 12 (preferably a sealing adhesive) opposite each other in the edge region, a second polymeric functional material 14 (conductive adhesive) is provided in a strip in the central region of the first adhesive contour 80 located between them.

[0050] exist Figure 7.1 The first adhesive profile 80 shown is, for example, constructed using a roller structure (as it is from...) Figure 3.1 (as can be seen in the image) is manufactured by having a continuously extending third coating surface 32, which extends centrally and is located within... Figure 3.1 As shown, between the longitudinally extending second coating surfaces 30.

[0051] In contrast, Figure 7.2 The second adhesive profile 82 is shown, which is consistent with the one shown in the image. Figure 7.1 The first adhesive profile 80 shown is different; it has a central region surrounded by a region of a first polymeric functional material 12 in the form of a sealing adhesive, and the first polymeric functional material is obtained by means of... Figure 3.2 Manufactured using a roller structure. Based on... Figure 3.2 In this roller structure, the roller shell 58 is configured such that the central region 32 is not continuously extended, but is interrupted by the first coating surface 28 that extends laterally.

[0052] Figure 8.1 and 8.2 A top view of the material container 72, configured as a trough 76, is shown schematically. It shows a space divider 74 that keeps the first polymer functional material separate from the second polymer functional material 14 within the material container 72.

[0053] from Figure 8.2 It can also be seen that the material container 72, which is constructed in the shape of a trough 76, has a width 84, which is less than its length 86.

[0054] Furthermore, the present invention relates to the application of a method for coating at least two polymer functional materials 12, 14 by means of a screen or stencil using a screen or stencil to manufacture a monopolar or bipolar plate from a substrate 10 in a stationary position 16. Furthermore, the present invention relates to the application of a method for coating at least two polymer functional materials 12, 14 to manufacture a monopolar or bipolar plate from a substrate 10 transported along a feed direction 66.

[0055] This invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, various modifications are possible within the scope set forth in the claims, which are within the framework of the art.

Claims

1. A method for simultaneously coating at least two polymer functional materials (12, 14) onto a substrate (10), the substrate being held in a stationary position (16) or moving along a feed direction (66), the method comprising at least the following steps: a) The first polymer functional material (12) is coated onto at least a first coating surface (28, 30) of the substrate (10) using at least one coating element (22, 26, 60, 62). b) Apply the second polymer functional material (14) to a coating surface (32) that is surrounded by or adjacent to the first coating surface (28, 30) by means of at least one coating element (24, 60, 62).

2. The method according to claim 1, characterized in that, According to method step a), a sealing adhesive is applied as the first polymer functional material (12).

3. The method according to claim 1, characterized in that, According to method step b), a conductive adhesive is applied as a second polymer functional material (14).

4. The method according to claims 1 to 3, characterized in that, According to method step a), at least the first coating surface (28, 30) is moved by the first and third coating elements (22, 26) in the first or second feed direction (36, 38).

5. The method according to claims 1 to 4, characterized in that, According to method step b), the third coating surface (32) is moved past by the second coating element (24).

6. The method according to claims 1 to 5, characterized in that, The coating elements (22, 24, 26) move above the screen or template (44).

7. The method according to claims 1 to 3, characterized in that, Method steps a) and b) are performed by a first coating roller (60) on the first active side (52) of the substrate (10).

8. The method according to claims 1 to 3 and 7, characterized in that, Method steps a) and b) are performed by first and second coating rollers (60, 62) on the first and second sides (52, 54) of the substrate (10).

9. The method according to claims 1 to 3, 7 and 8, characterized in that, The first polymer functional material (12) and the second polymer functional material (14) are removed from the material container (72), in which the first polymer functional material (12) and the second polymer functional material (14) are separated from each other by a space separator (74).

10. The method according to claims 1 to 3 and 7 to 9, characterized in that, The first polymer functional material (12) and the second polymer functional material (14) are conveyed onto the first coating roller (60) and / or the second coating roller (62) by means of an intermediate roller (64).

11. The method according to claims 1 to 3 and 7 to 10, characterized in that, A first adhesive profile (80) or a second adhesive profile (82) is applied to the first active side (52) of the substrate (10) (MPP).

12. The method according to claims 1 to 3 and 7 to 10, characterized in that, A first adhesive profile (80) and / or a second adhesive profile (82) are applied to the first active side (52) and the second active side (54) of the substrate (10) (BPP).

13. An application of the method according to claims 1 to 6 for fabricating a monopolar or bipolar plate by screen printing or stencil printing of at least two polymer functional materials (12, 14).

14. An application of the method according to claims 1 to 3 and 7 to 12 for coating at least two polymer functional materials (12, 14) to manufacture a monopolar plate or a bipolar plate.

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