Fuel cell manager

• US 6,339,313 B1
• Filed: 11/07/2000
• Issued: 01/15/2002
• Est. Priority Date: 07/05/1996
• Status: Expired due to Term

• Current Assignee: Estco Battery Management Incorporated
• Original Assignee: Estco Battery Management Incorporated
• Inventors: Adams, William A., Gardner, Christopher L.
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/706,858
• Time in Patent Office: 434 Days
• Field of Search: 320/121, 320/119, 320/162, 429/17
• US Class Current: 320/121
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A controller controls a switch bank which can shunt a voltage source in parallel with each fuel cell in a stack. By controlling the voltage of the voltage source, the current through the fuel cell is directly controlled. By increasing the anode potential of the fuel cell through control of the voltage source, poisons deposited on the electrocatalyst are removed, thereby rejuvenating the fuel cell. Each fuel cell in a stack can be treated in turn, causing a reduction of the effects of electrocatalyst poison on stack performance.

Claims

1. A device for reducing catalyst poisons in an individual fuel cull in a stack while said stack is in use, said stack having plurality of fuel cells coupled to each other in series, said device comprising:

a switch bank coupled to each fuel cell in the stack;

a controller controlling said switch bank;

measuring means to measure a voltage, said measuring means being coupled to said switch bank and to the controller; and

a variable voltage source coupled to the switch bank and to the controller,

wherein

said switch bank can couple the variable voltage source in parallel with any one of the plurality of fuel cells in said stack;

said switch bank can couple said measuring means to a fuel cell in the stack such that said measuring means can measure a voltage across said fuel cell; and

said controller controls a voltage setting of said variable voltage source and which fuel cell in said stack is coupled in parallel with said variable voltage source.

2. A method of reducing catalyst poisons in a fuel cell in a stack of fuel cells while said stack is in use, said method comprising:

a) choosing a fuel cell for which catalyst poisons are to be reduced;

b) determining a voltage across said fuel cell;

c) setting a voltage setting for a variable voltage source, said voltage setting being greater than said voltage across said fuel cell; and

d) momentarily coupling said variable voltage source to be in parallel with said cell.

3. A method as in claim 2 further including the steps of:

e) repeating steps b) to d) until said voltage across said fuel cell meets a threshold value.

4. A device for a stack having multiple fuel cells in the invent that a fuel cell in said stack is unable to produce its required power output, said device comprising:

a switch bank coupled to each fuel cell in the stack;

a controller controlling said switch bank;

measuring means to measure a voltage, said measuring means being coupled to said switch bank and to the controller; and

a variable voltage source coupled to the switch bank and to the controller,

wherein

said switch bank can couple the variable voltage source in parallel with any one of the plurality of fuel cells in said stack;

said switch bank can couple said measuring means to a fuel cell in the stack such that said measuring means can measure a voltage across said fuel cell;

said controller controls a voltage setting of said variable voltage source and which fuel cell in said stack is coupled in parallel with said variable voltage source.