Method and apparatus for monitoring equivalent series resistance and for shunting a fuel cell

• US 6,805,987 B2
• Filed: 05/06/2003
• Issued: 10/19/2004
• Est. Priority Date: 01/23/2002
• Status: Expired due to Term

• Current Assignee: Emergent Power Inc. (Plug Power Inc.)
• Original Assignee: Relion Incorporated (Plug Power Inc.)
• Inventors: Martin, Vanell L., Lott, David R., Bai, Lijun
• Primary Examiner(s): Maples, John S.
• Application Number:
  US10/430,928
• Publication Number:
  US 20030203249A1
• Time in Patent Office: 532 Days
• Field of Search: 429/13, 429/22, 429/23
• US Class Current: 429/431
• CPC Class Codes: H01G 11/08 Structural combinations, e.g. assembly or connection, of hybrid or EDL capacitors with other electric components, at least one hybrid or EDL capacitor being the main component
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell power system comprising a fuel cell having a cathode and an anode adapted to be coupled to a fuel supply, and which is configured to produce electrical power having a current and voltage output; a controller electrically coupled with the fuel cell, and configured to selectively short the anode to the cathode of the fuel cell; and circuitry configured to measure resistance of the fuel cell in timed relation to the shorting.

Claims

1. A fuel cell power method comprising:

providing a pair of output terminals;

providing a plurality of fuel cells respectively having an anode adapted to be coupled to a fuel supply, and a cathode, which fuel cells are selectively coupled to the output terminals, and which, in operation, convert chemical energy into electrical power having a current and voltage output, wherein one or more of the fuel cells are selectively decoupled from the output terminals while other fuel cells continue to provide power to the output terminals; and

measuring equivalent series resistance of one of the fuel cells, in situ, while the other fuel cells continue to produce electrical power.

2. A fuel cell power method in accordance with claim 1, wherein measuring equivalent series resistance comprises measuring equivalent series resistance using circuitry other than high frequency AC measurement circuitry.

3. A fuel cell power method in accordance with claim 1, wherein measuring equivalent series resistance of the fuel cell comprises providing a voltage sensor and a current sensor disposed in sensing relation relative to the anode and cathode of the fuel cell for which equivalent series resistance is being measured, and wherein equivalent series resistance is determined by shorting the anode and cathode of one of the fuel cells, measuring fuel cell voltage and current changes between before and immediately after a short is applied, and dividing the voltage change by the current change.

4. A fuel cell power method in accordance with claim 1, wherein measuring resistance of the fuel cell during shunting comprises providing a voltage sensor and a current sensor in sensing relation relative to the anode and cathode of the fuel cell to measure current generated by and voltage across the fuel cell, and wherein equivalent series resistance is determined by shorting the anode and cathode of one of the fuel cells, measuring fuel cell voltage and current changes between during shorting and immediately after a short is removed, and dividing the voltage change by the current change.