Disconnecting Procedure For Fuel Cell Systems

• US 20110097636A1
• Filed: 06/28/2005
• Published: 04/28/2011
• Est. Priority Date: 07/15/2004
• Status: Abandoned Application

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Weigele, Klaus, Post, Gerald, Schempp, Volker, Lederbogen, Mathias, Kurrle, Michael
• Application Number:
  US11/632,680
• Publication Number:
  US 20110097636A1
• Time in Patent Office: Days
• US Class Current: 429/429
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 8/04097 with recycling of the reactants H01M8/04119, H01M8/04104 take precedence
• CPC Class Codes: H01M 8/04126 Humidifying
• CPC Class Codes: H01M 8/04228 during shut-down
• CPC Class Codes: H01M 8/04238 Depolarisation
• CPC Class Codes: H01M 8/04303 applied during shut-down
• CPC Class Codes: H01M 8/04611 of the individual fuel cell
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04783 Pressure differences, e.g. between anode and cathode
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2457 with both reactants being gaseous or vaporised
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A method for shutting down a fuel cell system having at least one fuel cell, especially a fuel cell provided with a proton exchanging membrane, anode and cathode inlets, anode and cathode outlets, an anode recirculation circuit, a device which is operated according to the Venturi principle and is used to convey the gas in the anode recirculation circuit, and a hydrogen and air supply is disclosed. A method characterized by low emission values and high efficiency is provided. The hydrogen supply to the anode is interrupted during shutdown of the fuel cell system and the current generated from the residual hydrogen is supplied to an electric consumer.

Claims

1-9. -9. (canceled)

10. A method for shutting down a fuel cell system, the fuel cell system having at least one fuel cell having an anode and a cathode, anode and cathode inlets, anode and cathode outlets, an anode recycle loop, a device for delivering gas in the anode recycle loop, and a hydrogen and air supply, the hydrogen supply to the anode being interrupted during shutdown and a current generated from residual hydrogen being supplied to an electrical consumer, the method comprising:

regulating pressure in the cathode so that the pressure in the cathode deviates from pressure in the anode maximally by a pressure Δ

p_max of 0.2 bar.

11. The method as recited in claim 10 wherein the fuel cell system is first brought to a defined state.

12. The method as recited in claim 11 wherein the defined state is a no-load state.

13. The method as recited in claim 11 wherein the defined state is characterized by an absolute pressure in the anode of 1.6 bar.

14. The method as recited in claim 10 wherein an electrical connection between the anode and cathode is interrupted when a hydrogen pressure of the hydrogen supply drops below a minimum hydrogen pressure or a voltage drops below a minimum voltage on a fuel cell or below a minimum voltage on a fuel cell stack.

15. The method as recited in claim 10 wherein a duration of an electrical connection between the anode and cathode is controlled by the current supplied to the electrical consumer.

16. The method as recited in claim 10 wherein the gas from the anode recycle loop is supplied to the cathode outlet in a metered manner through at least one controllable media line.

17. The method as recited in claim 10 wherein circulation of the gas in the anode recycle loop is supported by a delivery device operated by electricity.

18. The method as recited in claim 10 wherein the electrical consumer is an electrical consumer of the fuel cell system and/or an electrical storage device.

19. The method as recited in claim 18 wherein the electrical storage device is a battery.

20. The method as recited in claim 10 wherein the at least one fuel cell is a fuel cell having a proton exchange membrane.

21. The method as recited in claim 10 wherein the device for delivering gas in the anode recycle loop is operated according to the Venturi principle.