Method for Determining the Sealing Tightness of a Fuel Cell Stack

Patent metadata

Field	Value
Publication number	US-2019334186-A1
Application number	US-201916506721-A
Country	US
Kind code	A1
Filing date	Jul 9, 2019
Priority date	Jan 10, 2017
Publication date	Oct 31, 2019
Grant date	—

Abstract

A method for determining a sealing tightness of a fuel cell stack includes providing of fuel into a cathode space, sealed off gas-tight against further components of a cathode subsystem, formed at least partly by the fuel cell stack, and detecting of a value which is indicative of a pressure change in the cathode space, where a cathode test pressure in the cathode space is higher than a pressure outside the fuel cell stack.

First claim

What is claimed is:

1 . A method for determining a sealing tightness of a fuel cell stack, comprising the acts of:
providing of fuel into a cathode space, sealed off gas-tight against further components of a cathode subsystem, formed at least partly by the fuel cell stack; and detecting of a value which is indicative of a pressure change in the cathode space, wherein a cathode test pressure in the cathode space is higher than a pressure outside the fuel cell stack.

2 . The method according to claim 1 , wherein the fuel is not provided, but rather, the fuel arrives from a fuel cell of the fuel cell stack from an anode side through an ion-selective separator of the fuel cell at a cathode side of the fuel cell.

3 . The method according to claim 1 , wherein, at least at a beginning of the detecting, a pressure in an anode space corresponds substantially to a pressure in the cathode space.

4 . The method according to claim 1 , wherein an anode subsystem is connected across at least one fuel line to the cathode space such that a pressure equalization occurs between an anode space and the cathode space.

5 . The method according to claim 4 , wherein the anode subsystem during the detecting is connected across the at least one fuel line to the cathode space such that fuel is flowable into the cathode space and a constant pressure equalization occurs between the anode space and the cathode space.

6 . The method according to claim 4 further comprising the acts of closing anode-side stack shutoff valves after the pressure equalization occurs and detecting a value which is indicative of a pressure change in the anode space, wherein an anode test pressure in the anode space is higher than the pressure outside the fuel cell stack.

7 . The method according to claim 1 further comprising the acts of closing an anode purge valve and cathode-side stack shutoff valves, subjecting an anode space to a greater pressure than the cathode space, and detecting a value which is indicative of a pressure change in the anode space.

8 . The method according to claim 1 , wherein at least as much fuel is provided in the cathode space such that an entire oxidizing agent present in the cathode space is converted.

9 . The method according to claim 1 , wherein cathode-side stack shutoff valves of the cathode subsystem are closed at least during the detecting and/or during the providing.

10 . The method according to claim 1 , wherein the fuel cell stack is used in a motor vehicle and wherein the sealing tightness is checked during a phase when the motor vehicle is not in use.

11 . The method according to claim 1 , wherein the fuel cell stack is used in a motor vehicle and wherein the sealing tightness is checked before a predicted use of the motor vehicle.

12 . The method according to claim 1 , wherein the fuel cell stack is used in a motor vehicle and wherein the sealing tightness is checked 10 minutes or 20 minutes or 30 minutes or 1 hour before a predicted use of the motor vehicle.

13 . The method according to claim 1 , wherein the detecting is done by making a nominal vs. an actual comparison:
between the cathode test pressure and a pressure actually detected in the cathode space after a definite time has elapsed; and/or between an anode test pressure and a pressure actually detected in an anode space after the definite time has elapsed.

14 . A method for starting a fuel cell system, comprising the acts of:
determining the sealing tightness according to claim 1 , wherein the fuel cell system is only started if the pressure change is less than a pressure change limit value.

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Formanski Volker
• Frisch Norbert
• Thomas Martin

Classifications

• H01M8/0438

  Pressure; Ambient pressure; Flow · CPC title

• H01M8/04302

  applied during start-up · CPC title

• H01M8/04082 Primary

  Arrangements for control of reactant parameters, e.g. pressure or concentration · CPC title

• H01M8/04225

  during start-up · CPC title

• H01M8/04432 Primary

  Pressure differences, e.g. between anode and cathode · CPC title