Bipolar plate for a fuel cell and method for manufacturing a bipolar plate
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- CELLCENTRIC GMBH & CO KG
- Filing Date
- 2013-07-09
- Publication Date
- 2026-07-23
AI Technical Summary
Existing bipolar plates for fuel cells are unstable and prone to shape cracks, making it difficult to attach seals reliably and leak-free.
A bipolar plate with an elastically deformable spring region and a stiffening structure, such as rivet connections or dome-shaped cavities, allows for injection-molding a seal onto the plate, ensuring precise alignment and leak-free attachment.
The solution provides a reliable, cost-effective, and leak-free method for attaching seals to bipolar plates, enhancing stability and preventing gas mixing within the fuel cell.
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Abstract
Description
[0001] The invention relates to a bipolar plate for a fuel cell and a method for producing a bipolar plate of the type specified in the preambles of the independent patent claims.
[0002] A generic bipolar plate for a fuel cell is disclosed in WO 2011 / 157377 A2. The bipolar plate shown there for a fuel cell for a motor vehicle includes a seal molded onto the bipolar plate.
[0003] Such bipolar plates are usually made from very thin-walled structures, such as sheet metal, and usually have relatively complex shapes. For this reason, such bipolar plates are usually relatively unstable and often also have shape cracks in the areas to which the seals are to be attached. A direct application of the seal by spraying the sealing material onto the bipolar plate is therefore relatively difficult.
[0004] It is the object of the present invention to provide a bipolar plate and a method for producing a bipolar plate of the type mentioned at the outset, by means of which a reliable attachment of a seal to a bipolar plate is made possible.
[0005] This object is achieved by a bipolar plate for a fuel cell and by a method for producing such a bipolar plate having the features of the independent patent claims. Advantageous configurations with expedient and non-trivial developments of the invention are specified in the dependent claims.
[0006] In order to improve the attachment of a seal to a bipolar plate, the bipolar plate according to the invention provides for the seal to be molded onto a spring region of the bipolar plate that is elastically deformable essentially in the vertical direction of the bipolar plate and is provided with a stiffening structure. It is therefore provided according to the invention to provide a stiffening structure on the elastically deformable spring area of the bipolar plate, which is usually also referred to as a sealing bridge. This stiffening of the molded part in the area of the sealing bridge enables a particularly simple and cost-effective stiffening of the bipolar plate, so that the seal can be injection-molded onto the bipolar plate in a process-reliable and, in particular, leak-free manner.
[0007] In an advantageous embodiment of the invention, it is provided that the bipolar plate has a cathode plate and an anode plate, which are arranged adjacent to one another in areas and are fastened to one another by means of the stiffening structure. As a result, the cathode plate and the anode plate can be positioned exactly in relation to one another and immediately joined together, with the stiffening structure thus fulfilling a dual function.
[0008] According to a further advantageous embodiment of the invention, it is provided that the stiffening structure comprises a plurality of dome-shaped cavities which are distributed in the longitudinal direction of the bipolar plate and have an opening, which are filled with the seal on the inside and provided with the seal on the outside. During the manufacturing process of the bipolar plate or during the injection molding of the seal, the sealing material is introduced into the cavities, whereby the bipolar plate is stiffened in this area, so that the subsequent external injection molding of the seal can take place without leaks and defects.
[0009] A further advantageous embodiment of the invention provides that the dome-shaped cavities are formed between the cathode plate and the anode plate and are delimited by means of a weld seam. This avoids leakage between the anode plate and the cathode plate, so that no sealing material can escape during the injection molding of the seal.
[0010] A further alternative embodiment of the invention provides that the stiffening structure comprises a plurality of rivet connections distributed in the longitudinal direction of the bipolar plate. In addition to stiffening the bipolar plate, the cathode plate and the anode plate can be fastened to one another in a particularly simple and cost-effective manner.
[0011] In the method according to the invention for producing a bipolar plate for a fuel cell, in particular a motor vehicle, a seal is injection molded onto the bipolar plate, with the method according to the invention being characterized in that the seal is injection molded onto a spring region of the bipolar plate which is essentially elastically deformable in the vertical direction of the bipolar plate , which is previously provided with a stiffening structure. Advantageous embodiments of the bipolar plate according to the invention are also to be regarded as advantageous embodiments of the method according to the invention.
[0012] Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention.
[0013] The drawing shows in:
[0014] figure 1 shows a partially sectioned perspective view of a bipolar plate for a fuel cell of a motor vehicle, wherein a spring area which serves as a sealing bridge and is essentially elastically deformable in the vertical direction of the bipolar plate is provided with a stiffening structure comprising a plurality of rivet connections;
[0015] figure 2 is a partially sectioned perspective view of FIG figure 1 along the bipolar plate shown in figure 1 marked sectional plane;
[0016] figure 3 shows a schematic representation of process steps for producing the rivet connections;
[0017] figure 4 shows a schematic representation of alternative method steps for producing the rivet connections;
[0018] figure 5 shows a perspective view of a section of the bipolar plate, an alternative stiffening structure being shown in the form of a dome-shaped cavity;
[0019] figure 6 is a partially sectioned perspective view of FIG figure 5 illustrated stiffening structure; and in
[0020] figure 7 is a sectional view of the stiffening structure formed as a dome-shaped cavity, the cavity being filled with a sealing material on the inside and provided with the same sealing material on the outside.
[0021] Elements that are the same or have the same function are provided with the same reference symbols in the figures.
[0022] A bipolar plate 10 for a fuel cell of a motor vehicle, not shown here, is a partially sectioned perspective view in FIG figure 1 shown. The bipolar plate 10 includes a cathode plate 12 and an anode plate 14 . Both the cathode plate 12 as well as the anode plate 14 have a substantially in the vertical direction z of the bipolar plate 10 elastically deformable spring area 16 , 18 on which with a stiffening structure 20 is provided.
[0023] The stiffening structure 20 comprises a plurality of in the longitudinal direction x of the bipolar plate 10 distributed riveted joints 22 . The bipolar plate 10 included in their pen area 16 a not shown here, molded seal 24 , which serves a plurality of bipolar plates 10 to be sealed against one another within the fuel cell, in such a way that reaction gases cannot mix with one another or with the reaction liquid.
[0024] In figure 2 is a partially sectioned perspective view of the bipolar plate 10 along the in figure 1 marked cutting plane A-A shown. As can be seen in the present case, the riveted joints 22 formed in that part of the cathode plate 12 each through a corresponding through-opening 26 inside the anode plate 14is slipped through. On the one hand, through the riveted connection 22 a reinforcement in the area of the spring areas 16 , 18 allows and on the other hand, the cathode plate 12 and the anode plate 14 positioned exactly to each other and fastened to each other.
[0025] In figure 3 are a schematic representation of four successive process steps for producing the riveted joints 22 shown. In a first method step, the passage opening 26 inside the anode plate 14 , for example by punching or the like, and a corresponding area of the cathode plate 12 reshaped accordingly.
[0026] In a subsequent process step, in the cathode plate 12 also a through hole 28 , For example, by punching made. After that, the one with the through hole 28 provided area of the cathode plate 12 through the through hole 26 everted through and finally the everted end region 30 to the underside of the anode plate 14 pressed to ensure a permanently stable and solid rivet connection 22 to train.
[0027] In figure 4 is an alternative sequence of process steps for making the riveted joints 22 shown. In the case shown here, it is a so-called cup riveting. In a first method step, the through-opening is again made 26 inside the anode plate 14 formed and the corresponding area of the cathode plate 12 reshaped accordingly. Then the formed area of the cathode plate 12 through the through hole 26 with its end area 30 slipped through and finally again to the underside of the anode plate 14 pressed and flattened.
[0028] In figure 5 is a section of the bipolar plate 10 shown with an alternative embodiment of the stiffening structure 20 is shown. The one in the figure 5 unspecified stiffening structure 20 comprises in the embodiment shown here a plurality of in the longitudinal direction x of the bipolar plate 10 distributed arranged, dome-shaped, a slit-shaped opening 32 having cavities 34 .
[0029] In figure 6 is a partially sectioned perspective view of FIG figure 5 shown bipolar plate 10 shown. As can be seen, the dome-shaped cavity shown here 34 between the cathode plate 12 and the anode plate 14 formed and by means of a weld 36 limited.
[0030] In figure 7 is a sectional view of the bipolar plate 10 shown, with the dome shaped opening 32 having cavity 34 you can see which one is on the inside with the seal 24 filled and on the outside with the seal 24 is provided. During injection of the sealing material onto the bipolar plate 10 penetrates into the cavity 34 in and solidifies there, forming the seal 24 on the bipolar plate 10 is firmly anchored. To prevent leakage of the sealing material from between the anode plate 12 and the cathode plate 14 trained cavity 34 to avoid is the in the figure 5 and figure 6 shown weld 36 intended. QUOTES INCLUDED IN DESCRIPTION
[0031] This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited
[0032] WO 2011 / 157377 A2
[0002]
Claims
[1] Bipolar plate for a fuel cell, in particular of a motor vehicle, with a connection to the bipolar plate ( 10 ) injection-molded seal ( 24 ), characterized by that the seal ( 24 ) to one essentially in the upward direction of the bipolar plate ( 10 ) elastically deformable spring area of the bipolar plate ( 10 ) is injected, which has a stiffening structure ( 24 ) is provided. [2] Bipolar plate ( 10 ) according to claim 1, characterized by that the bipolar plate ( 10 ) a cathode plate ( 12 ) and an anode plate ( 14 ) exhibits, which are arranged adjacent to each other in certain areas and are connected by means of the stiffening structure ( 20 ) are attached to each other. [3] Bipolar plate ( 10 ) according to claim 1 or 2, characterized by that the stiffening structure ( 20 ) a plurality of in the longitudinal direction (x) of the bipolar plate ( 10) distributed, dome-shaped, one opening ( 32 ) cavities ( 34 ) which includes the seal on the inside ( 24 ) filled and sealed on the outside ( 24 are provided. [4] Bipolar plate ( 10 ) according to claim 3, characterized by that the dome-shaped cavities ( 34 ) between the cathode plate ( 12 ) and the anode plate ( 14 ) formed and by means of a weld ( 36 are limited. [5] Bipolar plate ( 10 ) according to claim 1 or 2, characterized by that the stiffening structure ( 20 ) a plurality of in the longitudinal direction (x) of the bipolar plate ( 10 ) distributed rivet connections ( 22 ) includes. [6] Method for manufacturing a bipolar plate ( 10 ) for a fuel cell, in particular of a motor vehicle, in which a seal ( 24 ) to the bipolar plate ( 10) is sprayed, characterized by that the seal ( 24 ) to one essentially in the vertical direction (z) of the bipolar plate ( 10 ) elastically deformable spring area ( 16 , 18 ) the bipolar plate ( 10 ) is injected, which is previously coated with a stiffening structure ( 20 ) is provided.