Method for printing a substrate with sealing and / or adhesive, electrochemical cell having a printed seal
By introducing local protrusions on the substrate and forming gaps, the problem of bubble formation during stencil printing is solved, and the printing effect at a higher layer height is achieved, avoiding defects in the printing structure.
Patent Information
- Application Number
- CN202380063803.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-05
- Filing Date
- 2023-09-04
- Publication Date
- 2025-04-11
AI Technical Summary
During the stencil printing process, as the thickness of the stencil increases, bubbles are easily mixed when filling the notches of the seal and/or adhesive, resulting in defects in the printing structure.
By introducing local protrusions on the substrate and placing the template on the protrusions, a gap is formed to vent the air, thereby reducing the formation of air bubbles when filling the seal and/or adhesive.
The risk of bubble formation is significantly reduced, defects in the printing structure are avoided, and higher layer heights, such as 1500μm, can be achieved to meet the needs of electrochemical cell seals.
Smart Images
Figure CN119816963A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for printing a substrate with a seal and / or adhesive. The substrate can be, in particular, a layer or layer of an electrochemical cell, for example a monopolar plate, a bipolar plate, a separator plate and / or a membrane electrode assembly. Printing a substrate with a seal and / or adhesive is particularly useful for producing a seal. The invention also relates to an electrochemical cell with a printed seal. Background Art
[0002] Electrochemical cells, such as fuel cells, electrolytic cells or accumulators, have a multi-layer or multi-part structure. This structure requires a seal located in the middle in order to separate the supplied media from one another during the operation of the cell. To form the seal, a seal and / or adhesive is applied to the layers or strata of the cell. In particular, dispensing or printing methods are used here.
[0003] The large-scale production of electrochemical cells requires high introduction speeds, i.e. short cycle times, as well as high process stability. Stencil printing meets these requirements in particular. The printing process during stencil printing is basically divided into the following three sub-processes:
[0004] 1. Applying the seal and / or adhesive to the template that has been previously placed on the substrate to be printed,
[0005] 2. Filling one or more template slots with sealant and / or adhesive during the coating process,
[0006] 3. The seal and / or adhesive is released from the template notches by separating the template from the substrate.
[0007] The template thickness determines the layer height of the applied structure, with the layer height usually being in the range of 300 μm to 500 μm. However, for seals of electrochemical cells, layer heights of up to 1500 μm are required in order to compensate for tolerances and to be as free as possible in the design of the structure to be applied. This is because, depending on the respective sealing concept, the structure to be applied can be large and / or complex.
[0008] Therefore, in order to achieve the required layer height for the seals for electrochemical cells during stencil printing, thicker stencils must be used. However, this increases the risk of bubbles being introduced during the doctor blade process in order to fill the stencil slots with the applied seal and / or adhesive, which subsequently lead to defects. This is because as the thickness of the stencil increases, the volume of the stencil slots to be filled with the seal and / or adhesive also increases.
[0009] The problem is based on the following Figure 1a )and Figure 1b), which shows a template 3 with a slot 4 placed on a substrate 1, which needs to be filled with a sealant and / or adhesive 2. For this purpose, a scraper 12 is scraped on the upper side 3.1 of the template 3. The end of the scraper direction 8 towards the slot 4 cannot squeeze out all the air from the slot 4, so that bubbles 13 are formed in the slot 4, which prevent the slot 4 from being completely filled. In this case, the printed pattern has gaps or defects. The risk of containing bubbles 13 increases with the thickness d of the template 3. Summary of the invention
[0010] The object of the present invention is to reduce the risk of bubbles and thus defects when printing substrates with sealants and / or adhesives.
[0011] To achieve this object, a method is proposed having the features of claim 1 and an electrochemical cell having the features of claim 8. Advantageous developments of the invention can be gathered from the dependent claims.
[0012] A method for printing a substrate with a seal and / or adhesive using a template having an upper side, a lower side and at least one notch extending from the upper side to the lower side is proposed. The method comprises the following steps:
[0013] - providing a substrate having a side to be printed, the side to be printed having at least one local protrusion;
[0014] - placing the template onto at least one partial projection so that a gap remains between the underside of the template and the surface to be printed;
[0015] - applying a seal and / or adhesive to the upper side of the formwork;
[0016] Filling at least one slot of the template with a sealant and / or adhesive by means of a scraper which scrapes along a predetermined scraping direction on the top side of the template, wherein air present in the slot is forced out of the slot through the gap.
[0017] During filling with a sealant and / or adhesive, the slots of the template can be vented through the gap, so that the risk of bubble formation is significantly reduced. Venting through the gap thus helps to avoid defects in the printed structure, which is particularly meaningful when the method is used to produce seals, for example, on layers or layers of electrochemical cells.
[0018] In order to completely vent the notch, it is not necessary for the gap between the underside of the template and the surface to be printed to be designed in a circumferential manner and for the template to be raised over its entire surface relative to the surface to be printed. The template can also be placed regionally on the surface to be printed, in which case the position of the gap is predetermined by the scraper direction, since the gap is ideally located behind the notch in the scraper direction. This means that the notch is filled with sealing and / or adhesive in the region of the gap. If the gap is designed in a circumferential manner, the scraper direction can be selected arbitrarily.
[0019] Since the risk of bubble formation is significantly reduced in the proposed method, the template thickness can be increased, so that layer heights significantly exceeding 300 μm, for example 1500 μm, as required for seals of electrochemical cells, can also be achieved. Without a surrounding air gap, the layer height can vary slightly because the template is slightly tilted relative to the surface to be printed.
[0020] The at least one local projection for forming the gap is preferably introduced or applied in a preceding method step.
[0021] For example, before providing the substrate, at least one local protrusion may be formed in a forming process, such as an embossing process. If the substrate is a layer or a layer of an electrochemical cell, in particular a monopolar plate, a bipolar plate or a separator plate made of sheet metal, the at least one local projection can be introduced simultaneously with the production of these plates.
[0022] Alternatively, at least one local protrusion can be applied, especially welded or pasted to the substrate by applying a sheet before providing the substrate. Applying the sheet for forming at least one local protrusion can be carried out directly before the actual printing process. The sheet does not have to be made of the same material as the template. In particular, metal, especially aluminum or plastic is suitable as the material. The shape of the sheet is largely arbitrary. For example, the sheet can have an angular or rounded shape in a top view. In addition, more than one sheet can be applied to the surface to be printed on the substrate. Preferably, each applied sheet forms an independent local protrusion. If multiple sheets are applied, they are preferably arranged at a distance from each other.
[0023] The height of the at least one partial protrusion simultaneously defines the height of the gap in the region of the protrusion. If the template is placed regionally on the surface to be printed, the height of the gap changes. The maximum gap height is reached only in the region of the at least one partial protrusion. Outside of this region, the gap height decreases continuously until the region where the template is placed on the surface to be printed.
[0024] Preferably, by placing the template onto at least one partial protrusion, a gap is formed between the bottom side of the template and the surface to be printed, which gap has a height of 10-200 μm at least in the region of the partial protrusion. That is, at least one partial protrusion to be introduced or applied beforehand also has a height of 10-200 μm. The gap height is therefore relatively small, in particular compared to the height of the structure to be printed (if the structure is a seal of an electrochemical cell). The small gap height prevents penetration of the seal and / or adhesive, so that no smearing occurs on the surface to be printed. At the same time, the gap height is large enough to ensure the required venting of the notch when filling with the seal and / or adhesive.
[0025] Furthermore, the template can be in contact with the surface to be printed in certain areas when it is placed on the at least one partial projection. In this case, the template only projects in certain areas relative to the surface to be printed. The raised areas should then be positioned relative to the scraper direction so that the raised areas or gaps are located as close to the ends of the notches as possible in the scraper direction.
[0026] It is also proposed that when the template is placed on the at least one partial protrusion, a distance is maintained between the at least one notch and the at least one partial protrusion. This distance ensures reliable venting of the notch, since the partial protrusion is more easily circumvented by air when the template is placed. This distance is preferably 1-10 mm.
[0027] If at least one partial projection is formed by an applied sheet, this partial projection can be removed again after printing the substrate. Thus, the function of the printed substrate is not impaired by the at least one partial projection. In some cases, the sheet can even be reused.
[0028] The sheet can be adhered to the side to be printed of the substrate, for example, in accordance with a label. A labeling machine can then be used for applying the sheet.
[0029] Furthermore, the proposed electrochemical cell has at least one layer or layer which is printed with a seal and / or adhesive to form a seal. At least one sheet is applied, in particular welded or glued, at a distance from the seal to form the local protrusion. The distance between the sheet and the seal is preferably 1-10 mm.
[0030] In order to produce the proposed electrochemical cell, in particular the method according to the invention described above can be used. In this case, the seal can be considered to be free of defects, since the risk of bubble formation is minimized in the proposed method.
[0031] Preferably, the height H1 of the seal is greater than the height H2 of at least one sheet. Because when performing the above-described method according to the invention, the height H1 of the printed seal is composed of the height H2 of the sheet and the thickness of the template. The height H2 of the sheet is preferably 10-200 μm. The seal can have a height H1 of 1500 μm, for example.
[0032] The layers or strata of the electrochemical cell printed with seals and / or adhesives are preferably monopolar plates or bipolar plates, separator plates and / or membrane electrode assemblies. Because different media are guided between these layers or strata, the necessary media separation can be achieved with the help of printed seals. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. These drawings show:
[0034] Figure 1a) and 1b) respectively show a longitudinal section of a conventional device for printing a substrate during scraping with a doctor blade,
[0035] Figure 2 : A longitudinal section of a device for printing a substrate with a seal and / or adhesive according to the invention;
[0036] Figure 3 : A top view of a printed substrate, in particular a layer or a layer of an electrochemical cell with a printed seal;
[0037] Figure 4 : Figure 3 A longitudinal section of the base;
[0038] Figure 5 : Figure 4 An enlarged detail in a locally raised area of a substrate;
[0039] Figure 6 : Figure 3 An enlarged detail in a locally raised area of a substrate;
[0040] Figures 7 to 11 In each case a plan view of a printed substrate, in particular a layer or a layer of an electrochemical cell with a printed seal, is shown. DETAILED DESCRIPTION
[0041] At the beginning of the manual, Figure 1a )and Figure 1b ) describes the problem of bubble formation during stencil printing, so Figure 1a )and Figure 1b ) Refer to the beginning of the manual.
[0042] According to the following Figures 2 to 11 The invention and its advantages are described in more detail.
[0043] Figure 2A substrate 1 is shown, which is a layer or sublayer 10 of an electrochemical cell, for example a bipolar plate. The substrate 1 has a surface 1.1 to be printed, which is to be printed with a seal and / or adhesive 2 for forming a seal. The method according to the invention is used here.
[0044] In the method according to the invention, a sheet 9 is first applied, for example glued, to the surface 1.1 to be printed of the substrate 1, so that the sheet 9 forms a local protrusion 6. Alternatively, the local protrusion 6 can also be already formed into the substrate 1, so that the application of the sheet 9 is omitted. Subsequently, a template 3 having a notch 4 extending from the upper side 3.1 to the lower side 3.2 of the template 3 is placed onto the local protrusion 6, so that the template 3 is placed regionally on the local protrusion 6 and regionally on the surface 1.1 to be printed. As a result, in the region of the local protrusion 6, a gap 5 is formed between the lower side 3.2 of the template 3 and the surface 1.1 to be printed. Figure 2 In the embodiment, the gap 5 is arranged to the left of the slot 4 of the template 3. The position of the gap 5 relative to the slot 4 predetermines the scraper direction 8. The scraper direction 8 is the direction in which the scraper 7 is scraped on the upper side 3.1 of the template 3 in order to fill the slot 4 with the sealant and / or adhesive 2 that has been previously applied to the upper side 3.1 of the template 3. Figure 2 In the drawing, the scraper direction 8 is indicated by an arrow. That is, the scraper 7 scrapes past the slot 4 in the direction of the gap 5. The gap 5 thus enables complete venting of the slot 4, so that the slot 4 can be completely filled with the seal and / or adhesive 2. Due to the venting caused by the gap 5, there is no longer a risk of bubble formation.
[0045] When scraping off the seal and / or adhesive 2, pressure is applied to the template 3 by the scraper 7, which pressure may cause the template 3 to deform. Even in the case of deformation of the template 3, the local protrusions 6 ensure the formation of gaps 5, so that the notches 4 can be vented through the gaps. In order to support the template 3, as in Figure 2 As shown in FIG. 1 , a supporting element 12 can be provided which forms an additional support for the region of the template 3 that projects beyond the substrate 1 .
[0046] exist Figures 3 to 6 The embodiment shown in the figure shows a printed substrate 1. The substrate 1 is again a layer or layer 10 of an electrochemical cell, for example a bipolar plate. The substrate 1 has three openings at its two ends, which form ports 14 and are used for medium supply and medium discharge. The required medium separation is achieved by means of a seal 11, which is printed onto the substrate 1 according to the method of the invention.
[0047] This can be seen in a patch 9 which is arranged on the printed side 1 . 1 of the substrate 1 for forming the local elevations 6 .
[0048] The method according to the invention is used here, which can be seen in the local projections 6 in the form of applied tabs 9. The tabs 9 are at a distance a from the seal 11 in the region of the outer corners (see Figure 5 ) Arrangement (see Figure 6 ). The distance a ensures that the desired ventilation is not impaired by the blade 9. Positioning in the outer corner region enables ventilation in areas that are usually difficult to vent.
[0049] The web 9 has a height H2 which is significantly smaller than the desired height H1 of the seal 11. Since the height H2 of the web 9 is added to the height H1 of the seal 11 in the region of the partial projection 6, the height H1 of the seal 11 changes only slightly.
[0050] Instead of one sheet 9 arranged in the outer corner region of the seal 11, a plurality of sheets 9 can also be provided. Figure 7 As shown in FIG, further sheets 9 can also be provided in the region of another outer corner and of an inner corner, which is also usually difficult to vent. The position of the sheet 9 to the left of the seal 11 indicates that the scraper direction 8 is taken into account when positioning the sheet 9. This does not exclude the provision of further sheets 9 for forming the local protrusions 6, which extend beyond the corners (see FIG. Figure 8 ).
[0051] exist Fig. 9 In the embodiment of the present invention, only one sheet 9 is provided, specifically in the outer corner region of the seal 11. Figure 3 In contrast to the embodiment of FIG. 5 , the disc 9 has a circular shape in plan view.
[0052] Similar to Figure 7 and Figure 8 , it is also possible to provide a plurality of circular-shaped sheets 9 (see Fig.10 ).
[0053] Regardless of the shape, the sheets 9 can also be arranged at regular intervals around the seal 11, so that when the substrate 1 is printed to form the seal 11, the template 3 is completely convex relative to the surface 1.1 to be printed. In this case, the scraper direction 8 is irrelevant because the gap 5 is also designed to be circumferential.
Claims
1. A method for printing a substrate (1) with a seal and / or adhesive (2) using a template (3), the template having an upper side (3.1), a lower side (3.2) and at least one notch (4) extending from the upper side (3.1) to the lower side (3.2), the method comprising the following steps: - providing a substrate (1) having a side (1.1) to be printed, said side having at least one local protrusion (6); - placing the template (3) onto the at least one partial projection (6) such that a gap (5) remains between the underside (3.2) of the template (3) and the surface (1.1) to be printed; - applying the seal and / or adhesive (2) to the upper side (3.1) of the formwork (3); - filling the at least one groove (4) of the template (3) with the sealant and / or adhesive (2) with the aid of a scraper (7), which scrapes along a predetermined scraper direction (8) on the upper side (3.1) of the template (3), wherein the air present in the groove (4) is squeezed out of the groove (4) through the gap (5).
2. The method according to claim 1, It is characterized in that The at least one local projection (6) is introduced into the substrate (1) in a shaping process, for example an embossing process, before the substrate (1) is provided.
3. The method according to claim 1 or 2, It is characterized in that Before the substrate (1) is provided, the at least one partial projection (6) is applied, in particular welded or glued, to the substrate (1) by means of an application sheet (9).
4. The method according to any one of the preceding claims, It is characterized in that By placing the template (3) onto the at least one local protrusion, a gap (5) is formed between the lower side (3.2) of the template (3) and the surface (1.1) to be printed, the gap having a height (h) of 10 μm to 200 μm at least in the region of the local protrusion (6).
5. The method according to any one of the preceding claims, It is characterized in that When the template (3) is placed on the at least one partial elevation (6), it comes into contact with the surface (1.1) to be printed in certain areas.
6. The method according to any one of the preceding claims, It is characterized in that When the template (3) is placed on the at least one partial protrusion (6), the distance (a) between the at least one notch (4) and the at least one partial protrusion (6) is maintained, wherein the distance (a) is preferably 1 mm-10 mm.
7. The method according to any one of the preceding claims, It is characterized in that After printing the substrate (1), the at least one local projection (6) is removed again.
8. An electrochemical cell having at least one layer or stratum (10) printed with a sealing and / or adhesive (2) for forming a seal (11), wherein: At least one sheet (9) for forming the local projection (6) is applied, in particular welded or glued, at a distance (a) from the seal (11), the distance preferably being 1 mm to 10 mm.
9. The electrochemical cell according to claim 8, It is characterized in that The height (H1) of the seal is greater than the height (H2) of the at least one sheet (9), wherein the height (H2) is preferably 10 μm-200 μm.
10. The electrochemical cell according to claim 8 or 9, It is characterized in that The layer or strata (10) are monopolar or bipolar plates, separator plates and / or membrane electrode assemblies.