Fuel cell stack monitoring and system control

• US 6,692,851 B2
• Filed: 12/06/2001
• Issued: 02/17/2004
• Est. Priority Date: 07/06/1999
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Clingerman, Bruce J., Keskula, Donald H., Doan, Tien M.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): Alejandro, R
• Application Number:
  US10/011,097
• Publication Number:
  US 20020051899A1
• Time in Patent Office: 803 Days
• Field of Search: 429/13, 429/22, 429/23, 429/24, 429/25, 429/17
• US Class Current: 429/431
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 58/34 by heating
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04223 during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
• CPC Class Codes: H01M 8/04225 during start-up
• CPC Class Codes: H01M 8/04228 during shut-down
• CPC Class Codes: H01M 8/04302 applied during start-up
• CPC Class Codes: H01M 8/04303 applied during shut-down
• CPC Class Codes: H01M 8/04365 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04567 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04597 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04679 of fuel cell stacks
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.

Claims

1. A method for operating a fuel cell system with a fuel cell stack that supplies electrical power to an external load, comprising:

monitoring actual stack operating voltage that is produced by said fuel cell stack;

monitoring actual stack operating current that is produced by said fuel cell stack;

looking up an expected stack voltage and a high voltage variation limit in a lookup table using said actual operating current of said fuel cell stack as a first lookup table reference;

dividing said actual voltage by said expected voltage to generate an actual voltage variation signal;

comparing said actual voltage variation signal to said high voltage variation limit; and

generating a first signal if said actual voltage variation signal exceeds said high voltage variation limit.

2. The method of claim 1 further comprising:

looking up a low voltage variation limit in said lookup table;

comparing said actual voltage variation signal to said low voltage variation limit; and

generating a second signal if said actual voltage variation signal exceeds said low voltage variation limit.

3. The method of claim 2 further comprising employing fuel cell stack temperature as a second lookup table reference.

4. The method of claim 2 further comprising employing fuel cell stack pressure as a second lookup table reference.