Electrochemical device and method for producing an electrochemical unit for an electrochemical device

Patent metadata

Field	Value
Publication number	US-10833337-B2
Application number	US-201715837146-A
Country	US
Kind code	B2
Filing date	Dec 11, 2017
Priority date	Jun 12, 2015
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

An electrochemical device is provided that includes a stack of a plurality of electrochemical units that succeed one another in a stacking direction and each include an electrochemically active membrane electrode assembly, at least one gas diffusion layer and a bipolar plate having at least one flow field, in which at least one flow field is sealed off simply and reliably and the occurrence of parasitic flows is prevented, wherein at least one bipolar plate has at least one edge web, which borders a flow field of the bipolar plate and is in contact with a gas diffusion layer adjacent to the bipolar plate, and wherein the electrochemical device further includes at least one flow field seal element that seals off the flow field bordered by the edge web and is in contact with the edge web and in contact with the gas diffusion layer.

First claim

The invention claimed is:

1. An electrochemical device, including
a stack of a plurality of electrochemical units that succeed one another in a stacking direction and each include an electrochemically active membrane electrode assembly, at least one gas diffusion layer and a bipolar plate having at least one flow field for at least one fluid medium,
wherein
at least one bipolar plate has at least one edge web, which borders a flow field of the bipolar plate at least in certain areas and is in contact with a gas diffusion layer adjacent to the bipolar plate, wherein the electrochemical device further includes at least one flow field seal element that seals off the flow field bordered by the edge web and is in contact with the edge web and in contact with the gas diffusion layer; and
wherein two bipolar plate that succeed one another in the stacking direction are provided on mutually facing sides with a respective edge web that is in contact with a respective flow field seal element, wherein the flow field seal elements with which the edge webs of the bipolar plates are in contact abut against one another in sealing manner.

2. The electrochemical device according to claim 1 , wherein the flow field seal element is connected to the edge web in a substance-to-substance bond.

3. The electrochemical device according to claim 1 , wherein the flow field seal element is connected to the gas diffusion layer in a substance-to-substance bond.

4. The electrochemical device according to claim 1 , wherein the flow field seal element is an injection molded part that is formed onto the edge web and/or onto the gas diffusion layer.

5. The electrochemical device according to claim 1 , wherein the flow field seal element is produced on the edge web and/or the gas diffusion layer by a pattern printing method.

6. The electrochemical device according to claim 1 , wherein the bipolar plate has on its anode side an anode-side edge web and on its cathode side a cathode-side edge web, wherein the anode-side edge web and the cathode-side edge web are offset from one another at least in certain areas, in an offset direction running perpendicular to the stacking direction.

7. The electrochemical device according to claim 6 , wherein the bipolar plate has, in an intermediate region between the anode-side edge web and the cathode-side edge web, at least one aperture for a fluid medium to pass through the bipolar plate or into an interior of the bipolar plate.

8. The electrochemical device according to claim 7 , wherein the at least one aperture is in fluidic connection with a medium channel that extends through the bipolar plate in the stacking direction.

9. The electrochemical device according to claim 1 , wherein at least one membrane electrode assembly is provided with an edge reinforcing arrangement against which the flow field seal element abuts in sealing manner.

10. The electrochemical device according to claim 1 , wherein the two bipolar plates that succeed one another in the stacking direction take a substantially identical form but are arranged rotated by an angle of 180° to one another about an axis of rotation that is parallel to the stacking direction.

11. The electrochemical device according to claim 1 , wherein at least one bipolar plate having an edge web that is in contact with a flow field seal element includes two bipolar plate layers that are joined to one another along join lines.

12. The electrochemical device according to claim 11 , wherein the bipolar plate layers are joined to one another along join lines by welding and/or by adhesion.

13. The electrochemical device according to claim 11 , wherein the flow field seal element that is arranged on the bipolar plate does not overlap the join lines as seen in the stacking direction.

14. The electrochemical device according to claim 1 , wherein at least one bipolar plate includes two bipolar plate layers that are sealed off from the surroundings at at least one of the bipolar plate layers by producing a seal.

15. The electrochemical device according to claim 1 , wherein the flow field seal element that is in contact with the edge web of a first bipolar plate and in contact with a first gas diffusion layer extends as far as a second bipolar plate opposite the first bipolar plate.

16. The electrochemical device according to claim 1 , wherein the flow field seal element that is in contact with the edge web of a first bipolar plate and in contact with a first gas diffusion layer abuts in sealing manner against a further flow field seal element that is in contact with a second gas diffusion layer and abuts in sealing manner against a second bipolar plate opposite the first bipolar plate.

17. A method for producing an electrochemical unit for an electrochemical device in which a plurality of electrochemical units succeed one another in a stacking direction,
wherein the electrochemical unit includes an electrochemically active membrane electrode assembly, at least one gas diffusion layer and a bipolar plate having at least one flow field for at least one fluid medium and at least one edge web, which borders a flow field of the bipolar plate at least in certain areas and is in contact with a gas diffusion layer adjacent to the bipolar plate, and
wherein the method includes the following:
arranging the gas diffusion layer on the bipolar plate or on a bipolar plate layer of the bipolar plate;
producing a flow field seal element on the bipolar plate or the bipolar plate layer and on the gas diffusion layer such that the flow field seal element is in contact both with the bipolar plate or the bipolar plate layer and also with the gas diffusion layer;
providing two bipolar plates that succeed one another in the stacking direction on mutually facing sides with a respective edge web that is in contact with a respective flow field seal element, wherein the flow field seal elements with which the edge webs of the bipolar plates are in contact abut against one another in sealing manner.

18. The method according to claim 17 , wherein the bipolar plate has at least one edge web, which borders a flow field of the bipolar plate at least in certain areas,
wherein during production of the flow field seal element the gas diffusion layer is in contact with the edge web.

19. The electrochemical device according to claim 14 , wherein the seal is made from an elastomer material.

Assignees

• Elringklinger Ag

Inventors

• Stahl Peter
• Kraft Juergen
• Goetz Michael

Classifications

• C25B9/19

  with diaphragms · CPC title

• C25B9/77

  having diaphragms · CPC title

• C25B9/73

  of the filter-press type · CPC title

• H01M8/2483

  characterised by internal manifolds · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title