CA-3202576-C - METHOD OF ATTACHING A GASKET ON A BIPOLAR PLATE

Abstract

The invention relates to a method for securing a gasket (4) on a bipolar plate (12). The method comprises the steps of applying and aligning a first gasket film (4a) to and on a second gasket film (4b) having connection recesses (8), of connecting the first gasket film (4a) to the second gasket film (4b) such that the gasket (4) is formed, of placing the gasket (4) onto the bipolar plate (12) such that the second gasket film (4b) lies with the connection recesses (8) on the bipolar plate (12), and of carrying out an embossing step, in which an embossing force is applied in the region of the connection recesses (8) by an embossing tool (20) such that an embossed adhesive point (24) is formed and the first gasket film (4a) is connected to the bipolar plate (12) via an adhesive (16) arranged in the connection recess (8) on the first gasket film (4a).

Inventors

• Christoph Haluschka
• Mattias HOLMBERG
• Stefan MUNTHE
• Stefan Andersch
• Holger Dziallas
• Jens-Peter Suchsland
• Eberhard Maier
• Ali Riza Yildirim
• Martin Gerlach
• Anton Ringel
• Andreas Ringk
• Florian Alexander Knorr
• Aude Muller
• Jenny Andersson

Assignees

• ROBERT BOSCH GMBH
• POWERCELL SWEDEN AB
• GREENERITY GMBH

Dates

Publication Date

20260505

Application Date

20211217

Priority Date

20201217

Claims (10)

1. Claims 1. A method of securing a gasket (4) with a bipolar plate (12) comprising the 5 steps of: - Application and alignment of a first gasket foil (4a) on a second gasket foil (4b) having connection recesses (8), - Bonding the first gasket foil (4a) to the second gasket foil (4b) so that the gasket (4) is formed, 10 - Placing the gasket (4) on the bipolar plate (12) so that the second gasket foil (4b) rests against the bipolar plate (12) with the connection recesses (8), - Performing an embossing step in which an embossing force is applied with an embossing tool (20) in a region of the connection recesses (8) so 15 that an embossed adhesive dot (24) is formed and the first gasket foil (4a) is bonded to the bipolar plate (12) via an adhesive (16) disposed in the connection recess (8) on the first gasket foil (4a).
2. 2. The method of claim 1, wherein the adhesive (16) is applied to at least the 20 first gasket foil (4a) prior to joining the first gasket foil (4a) to the second gasket foil (4b).
3. 3. Method according to claim 1 or 2, wherein the adhesive (16) is a UV adhesive, so that the UV adhesive is cured by means of a UV source.
4. 4. The method according to claim 2, wherein the adhesive (16) is a hot glue, so that the gasket films (4a, 4b) are joined together by means of a laminating process. 30
5. 5. The method according to any one claims 1 to 4, wherein the embossing force is applied to the first gasket foil (4a).
6. 6. The method according to claim 4, wherein with the embossing step, the embossing tool (20) is heated so that the hot glue disposed in the connection 35 recess (8) bonds to the bipolar plate (12).
7. 7. Fuel cell (1) for a fuel cell stack, the fuel cell (1) having at least one bipolar plate (12) and a gasket (4), in which the gasket (4) comprises a first and a second gasket foil (4a, 4b), the second gasket foil (4b) having connection recesses (8) and bearing against the bipolar plate (12) and the gasket (4) is bonded to the bipolar plate (12) via embossed adhesive dots (24) formed in the region of the connection recesses (8) by means of adhesive (16) disposed in the connection recesses (8).
8. 8. Fuel cell (1) according to claim 7, wherein the adhesive dots (24) have a geometric shape in which an adhesive dot side (q) of the geometric shape runs parallel to a transverse center axis (32) of the bipolar plate (12) and is aligned with this transverse center axis (32).
9. 9. Fuel cell (1) according to claim 8, wherein the adhesive dots (24) additionally have an adhesive dot side (l) that runs parallel to a longitudinal center axis (40) and is aligned with this longitudinal center axis (40).
10. 10. A fuel cell stack comprising a plurality of fuel cells 15 (1) according to any one of claims 7 to 9.

Description

Method of attaching a gasket with a bipolar plate The present invention relates to a method of attaching a gasket to a bipolar plate and to a fuel cell manufactured according to such method. Prior art Fuel cells are electrochemical energy converters in which, for example, hydrogen and oxygen are converted into water, electrical energy and heat. Fuel cells or fuel cell stacks are made up of multi-part cells which have membrane electrode units and bipolar plates arranged alternately on top of each other. The bipolar plates are used to supply the electrodes with reactants and to 20 cool the fuel cell stack. For this purpose, the bipolar plates have a distributor structure that guides reactant-containing fluids along the electrodes. In addition, the distributor structures serve to guide a cooling fluid along the further distributor structures. These distributor structures are designed as channels through which the different 25 fluids can be conducted. DE 10 2005 058 370 A1 describes a fuel cell which has two bipolar plates, a membrane electrode unit being arranged between the bipolar plates and a gas diffusion layer being arranged between the membrane electrode unit and the 30 bipolar plates. The membrane electrode unit is arranged on a support frame. An ultrasonic welded joint is formed between the membrane electrode unit and the support frame, via which the membrane electrode unit is connected to the support frame. 35 It is also known from the prior art that the carrier frame is directly connected to the bipolar plate via an ultrasonic welded joint. Likewise, a welded joint produced by means of a laser can be used instead of the ultrasonic welded joint. Although these methods have the advantage that no additional material is required, a rough surface is nevertheless necessary. The object of the present invention is to provide a method of attaching a gasket to a bipolar plate in which the gasket can be attached to 5 the bipolar plate in a simple and economical manner with little additional material. 10 Disclosure of the invention A method is proposed for attaching a gasket to a bipolar plate, comprising the steps of applying and aligning a first gasket foil to a second gasket foil having connection recesses, connecting the first gasket foil to the second gasket foil so 15 that the gasket is formed, placing the gasket on the bipolar plate so that the second gasket foil with the connection recesses abuts the bipolar plate. In a further process step, an embossing step is carried out in which an embossing force is applied with an embossing tool in the region of the connection recesses so that an embossed adhesive point is formed and the first gasket foil is 20 connected to the bipolar plate via an adhesive agent arranged in the connection recess on the first gasket foil. A connection recess within the meaning of the present invention is understood to be an opening through the second gasket foil which enables a bonding. A 25 bonding point is understood to be the area where the first gasket foil is bonded to the bipolar plate. Through the embossing step, the gasket is connected to the bipolar plate only in the area of the connection recesses. This connection is achieved by means of a simple embossing step. In addition, an adhesive only has to be provided in the area of the connection recesses. As a result, little 30 adhesive is thus required to secure the gasket to the bipolar plate. Accordingly, only little additional material is required. Moreover, such a process can thus be carried out simply and economically. In a preferred embodiment of the invention, an adhesive is applied to at least the first gasket film prior to bonding the first gasket film to the second gasket film. The first and second gasket films are thus joined together 5 via an adhesive bond. Adhesive means is further arranged in this region through the connection recess. The gasket is bonded to the bipolar plate via this adhesive. Thus, no additional step is required to apply the adhesive. Since this adhesive agent is applied to join the first and second gasket films, no additional material is required to join the 10 gasket to the bipolar plate. Thus, such a process can be carried out easily and economically. In a further preferred embodiment of the invention, the adhesive is a UV adhesive, so that the UV adhesive is cured by means of a UV source. Preferably, 15 at least the first gasket film is transparent to UV light so that the adhesive can be cured using a UV source. This process step allows the gasket to be bonded to the bipolar plate at a specific point in time, so that position correction is still possible. In addition, curing via UV light enables simple and controlled attachment. Preferably, the adhesive is a hot melt adhesive, so that the gasket films are bonded together by means of a laminating process. A hot melt adhesive is an adhesive that changes to an adhesive state when exposed to heat. By means of such a process step, it is possible