Cascaded fuel cell stack and fuel cell system

Patent metadata

Field	Value
Publication number	US-2021288343-A1
Application number	US-201816490437-A
Country	US
Kind code	A1
Filing date	Dec 6, 2018
Priority date	Jan 17, 2018
Publication date	Sep 16, 2021
Grant date	—

Abstract

A fuel cell stack is provided comprising a plurality of fuel cells comprising a membrane electrode assembly and at least one gas diffusion layer, which fuel cells are divided into at least one first fuel cell segment having a portion of the plurality of fuel cells and a second fuel cell segment having a different portion of the plurality of fuel cells, wherein the first fuel cell segment and the second fuel cell segment are arranged in a common fuel cell cascade, wherein the first fuel cell segment comprises a first collector inlet line for an operating medium and a first collector outlet lined which is formed integrally with a second collector inlet line of the second fuel cell segment and wherein the second fuel cell segment comprises a second collector outlet line. The membrane electrode assemblies and/or the gas diffusion layers inside the second fuel cell segment are designed in such a way that they are more water-repellent than those of the first fuel cell segment. A fuel cell system comprising such a fuel cell stack is also provided.

First claim

1 . A fuel cell stack, comprising:
a first fuel cell segment including a first plurality of fuel cells, wherein each of the fuel cells of the first plurality of fuel cells includes a membrane electrode assembly and at least one gas diffusion layer; and a second fuel cell segment including a second plurality of fuel cells, wherein each of the fuel cells of the second plurality of fuel cells includes a membrane electrode assembly and at least one gas diffusion layer, wherein the first fuel cell segment and the second fuel cell segment are arranged in a common fuel cell cascade, wherein the first fuel cell segment includes a first collector inlet line for an operating medium and a first collector outlet line which is formed integrally with a second collector inlet line of the second fuel cell segment, wherein the second fuel cell segment includes a second collector outlet line, and wherein the membrane electrode assemblies and/or the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment are more water-repellent than the membrane electrode assemblies and/or the gas diffusion layers of the fuel cells of the first plurality of fuel cells of the first fuel cell segment.

2 . The fuel cell stack according to claim 1 , wherein an equivalent weight of membranes of the membrane electrode assemblies of the first plurality of fuel cells of the first fuel cell segment is less than an equivalent weight of membranes of the membrane electrode assemblies of the second plurality of fuel cells of the second fuel cell segment.

3 . The fuel cell stack according to claim 1 , wherein a thickness of membranes of the membrane electrode assemblies of the first plurality of fuel cells of the first fuel cell segment is less than the thickness of membranes of the membrane electrode assemblies of the second plurality of fuel cells of the, second fuel cell segment.

4 . The fuel cell stack according to claim 3 , wherein the thickness of the membranes of the membrane electrode assemblies of the first plurality of fuel cells of the first fuel cell segment is between 4 and 12 micrometers, and the thickness of the membranes of the membrane electrode assemblies of the second plurality of fuel cells of the second fuel cell segment is between 14 and 35 micrometers.

5 . The fuel cell stack according to claim 1 , wherein the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment have a greater porosity than the gas diffusion layers of the fuel cells of the first plurality of fuel cells of the first fuel cell segment.

6 . The fuel cell stack according to claim 1 , wherein the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment have a hydrophobic coating.

7 . The fuel cell stack according to claim 1 , wherein the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment comprise a microporous layer and a macroporous layer, and the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment have a hydrophobic coating on the microporous layer and/or the macroporous layer.

8 . The fuel cell stack according to claim 1 , wherein the gas diffusion layers of the fuel cells of the first plurality of fuel cells of the first fuel cell segment comprise a microporous layer and a macroporous layer, and the gas diffusion layers of the fuel cells of the first plurality of fuel cells of the first fuel cell segment have a hydrophilic coating on the microporous layer and/or on the macroporous layer.

9 . The fuel cell stack according to claim 1 , wherein the membrane electrode assemblies and/or the gas diffusion layers have a hydrophobicity gradient running between the first collector inlet line and the second collector outlet line.

10 . A fuel cell system for a motor vehicle, comprising:
a fuel cell stack including:
a first fuel cell segment including a first plurality of fuel cells wherein each of the fuel cells of the first plurality of fuel cells includes a membrane electrode assembly and at least one gas diffusion layer; and
a second fuel cell segment including a second plurality of fuel cells, wherein each of the fuel cells of the second plurality of fuel cells includes a membrane electrode assembly and at least one gas diffusion layer,
wherein the first fuel cell segment and the second fuel cell segment are arranged in a common fuel cell cascade, wherein the first fuel cell segment includes a first collector inlet line for an operating medium and a first collector outlet line which is formed integrally with a second collector inlet line of the second fuel cell segment, wherein the second fuel cell segment includes a second collector outlet line, and wherein the membrane electrode assemblies and/or the gas diffusion layers of the fuel cells of the second plurality of fuel cells of the second fuel cell segment are more water-repellent than the membrane electrode assemblies and/or the gas diffusion layers of the fuel cells of the first plurality of fuel cells of the first fuel cell segment.

Assignees

• Audi Ag
• Volkswagen Ag

Inventors

• Ermatschenko Natalja
• Lucas Christian
• Hübner Gerold

Classifications

• H01M8/0228

  in the form of layered or coated products · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/249 Primary

  comprising two or more groupings of fuel cells, e.g. modular assemblies · CPC title

• H01M8/04291 Primary

  Arrangements for managing water in solid electrolyte fuel cell systems (H01M8/04119 takes precedence) · CPC title