Reduction of cell degradation in fuel cell systems

Patent metadata

Field	Value
Publication number	US-11322758-B2
Application number	US-201916967392-A
Country	US
Kind code	B2
Filing date	Jan 23, 2019
Priority date	Feb 5, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A method for reducing cell degradation in a fuel cell system includes adding oxygen-containing gas to a fuel in the anode chamber to prevent an increase in a cell voltage above a predetermined maximum value.

First claim

The invention claimed is:

1. A method for reducing cell degradation in a fuel cell system, comprising:
preventing a cell voltage of a fuel cell in the fuel cell system established during a load mode from increasing above 0.75 V during an idling mode, a cycling mode, or during starting or restarting of the fuel cell system by adding an oxygen-containing gas to a fuel in an anode chamber of the fuel cell, wherein only enough oxygen-containing gas is added to the fuel for the cell voltage to not rise above 0.75 V.

2. The method according to claim 1 , wherein the oxygen-containing gas is added to the fuel at a stack entry.

3. The method according to claim 1 , wherein the oxygen-containing gas is added to the fuel via a connecting line between a cathode chamber and the anode chamber.

4. The method according to claim 1 , wherein the oxygen-containing gas is added to the fuel by applying a pressure differential to a membrane between the anode chamber and a cathode chamber.

5. The method according to claim 1 , wherein the fuel is hydrogen.

6. The method according to claim 1 , wherein the oxygen-containing gas is air.

7. A device for reducing cell degradation in a fuel cell system, comprising:
means for adding an oxygen-containing gas to a fuel; and
a control device configured to control the means for adding the oxygen-containing gas to the fuel,
wherein the control device is configured to prevent a cell voltage of a fuel cell in the fuel cell system established during a load mode from increasing above 0.75 V during an idling mode, a cycling mode, or during starting or restarting of the fuel cell system by adding an oxygen-containing gas to a fuel in an anode chamber of the fuel cell,
wherein the control device is configured to regulate metering of the oxygen-containing gas to the fuel and thus regulates the cell voltage, and
wherein the control device is configured to add only enough oxygen-containing gas to the fuel for the cell voltage to not rise above 0.75 V.

8. The device according to claim 7 , wherein the means for adding an oxygen-containing gas to the fuel comprises a gas supply line including a metering valve to an inlet region of the fuel into the fuel cell system.

9. The device according to claim 7 , wherein the means for adding an oxygen-containing gas to the fuel comprises a connecting line including a metering valve between a cathode chamber and the anode chamber of the fuel cell.

10. The device according to claim 7 , wherein:
the means for adding an oxygen-containing gas to the fuel includes pumps and/or a compressor with which an overpressure can be generated on a cathode side of the fuel cell with respect to an anode side of the fuel cell; and
the control device regulates the pumps and/or the compressor and thus sets a permeation rate of the oxygen-containing gas through a membrane from the cathode side of the fuel cell to the anode side of the fuel cell.

Assignees

• Audi Ag
• Volkswagen Ag

Inventors

• Stiefel Miriam
• Schmidt Lasse
• Hübner Gerold

Classifications

• H01M8/04225

  during start-up · CPC title

• H01M8/04302

  applied during start-up · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04552

  of the individual fuel cell · CPC title

• H01M8/04238

  Depolarisation · CPC title