Method and apparatus for fuel cell systems

• US 7,419,734 B2
• Filed: 05/16/2003
• Issued: 09/02/2008
• Est. Priority Date: 05/16/2003
• Status: Expired due to Fees

• Current Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Original Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Inventors: Pearson, Martin T.
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): Lewis; Ben
• Application Number:
  US10/440,451
• Publication Number:
  US 20040229095A1
• Time in Patent Office: 1,936 Days
• Field of Search: 429/21, 429/13, 429/22
• US Class Current: 429/431
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04679 of fuel cell stacks
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04917 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/249 comprising two or more groupings of fuel cells, e.g. modular assemblies
• CPC Class Codes: H02J 1/001 Hot plugging or unplugging of load or power modules to or from power distribution networks
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Claims

1. A power supply system, comprising:

a first set of fuel cell systems electrically coupled in series to one another and operable to produce a first voltage there across; and

a second set of fuel cell systems electrically coupled in series to one another and operable to produce a voltage there across, where each of the fuel cell systems in the second set of fuel cell systems is electrically coupled in parallel to a respective one of the fuel cell systems in the first set of fuel cell systems,

wherein each of the fuel cell systems comprises;

a fuel cell stack,

an ultracapacitor electrically coupled in parallel with the fuel cell stack,

a charging current limiter electrically coupled to limit a charging current from the fuel cell stack to the ultracapacitor, and

a charging current limiter bypass device electrically coupled to provide a discharge path from the ultracapacitor bypassing the charging current limiter.

2. The power supply system of claim 1, further comprising:

a third set of fuel cell systems electrically coupled in series to one another and operable to produce a voltage there across, where each of the fuel cell systems in the third set of fuel cell systems is electrically coupled in parallel to a respective one of the fuel cell systems in the second set of fuel cell systems.

3. The power supply system of claim 2 wherein the number of fuel cell systems in the first set of fuel cell systems is equal to the number of fuel cell systems in the second set of fuel cell systems and wherein the number of fuel cell systems in the third set of fuel cell systems is less than the number of fuel cell systems in the second set of fuel cell systems.

4. The power supply system of claim 2, further comprising:

a first tap electrically coupled to a first end of the first and the second sets of fuel cell systems to provide a first potential;

a second tap electrically coupled to a second end of the first and the second set of fuel cell systems to provide a second potential; and

a third tap electrically coupled to a first end of the third set of fuel cell systems to provide a third potential, different from the first and the second potentials, where the first tap and second tap form a first voltage bus and the first tap and the third tap form a second voltage bus.

5. The power supply system of claim 2, further comprising:

a fourth set of fuel cell systems electrically coupled in series to one another and operable to produce a voltage there across, where each of the fuel cell systems in the fourth set of fuel cell systems is electrically coupled in parallel to a respective one of the fuel cell systems in the third set of fuel cell systems.

6. The power supply system of claim 5 wherein the number of fuel cell systems in the fourth set is one.

7. The power supply system of claim 5 wherein the number of fuel cell systems in the first set of fuel cell systems is equal to the number of fuel cell systems in the second set of fuel cell systems and wherein the number of fuel cell systems in the third set of fuel cell systems is less than the number of fuel cell systems in the second set of fuel cell systems and the number of fuel cell systems in the fourth set of fuel cell systems is less than the number of fuel cell systems in the third set of fuel cell systems.

8. The power supply system of claim 5, further comprising:

a first tap electrically coupled to a first end of the first and the second sets of fuel cell systems to provide a first potential;

a second tap electrically coupled to a second end of the first and the second set of fuel cell systems to provide a second potential;

a third tap electrically coupled to a first end of the third set of fuel cell systems to provide a third potential, different from the first and the second potentials; and

a fourth tap electrically coupled to a first end of the fourth set of fuel cell systems to provide a fourth potential, where the first tap and second tap form a first voltage bus, the first tap and the third tap form a second voltage bus, and the first tap and the fourth tap forms a third voltage bus.

9. The power supply system of claim 5, further comprising:

a first tap electrically coupled between a first and a second end of the first and the second sets of fuel cell systems to provide a reference potential;

a second tap electrically coupled to the first end of the first and the second sets of fuel cell systems to provide a first potential, the first potential above the reference potential;

a third tap electrically coupled to the second end of the first and the second sets of fuel cell systems to provide a second potential, the second potential below the reference potential;

a fourth tap electrically coupled to a first end of the third set of fuel cell systems to provide a third potential, the third potential above the reference potential and below the first potential;

a fifth tap electrically coupled to a first end of the fourth set of fuel cell systems to provide a fourth potential, the fourth potential above the reference potential and below the third potential; and

a sixth tap electrically coupled to a second end of the fourth set of fuel cell systems to provide a fifth potential, the fifth potential below the reference potential and above the second potential.

10. The power supply system of claim 9 wherein the third tap is further electrically coupled to the second end of the third set of fuel cell systems.

11. The power supply system of claim 9 wherein the first tap and second tap form a first voltage bus, the first tap and the third tap form a second voltage bus, and the first tap and the fourth tap forms a third voltage bus, the first tap and the fifth tap form a fourth voltage bus, and the first tap and the sixth tap form a fifth voltage bus.

12. The power supply system of claim 9 wherein the first potential is approximately 120 volts above the reference potential, the second potential is approximately 48 volts below the reference potential, the third potential is approximately 48 volts above the reference potential, the fourth potential is approximately 24 volts above the reference potential and the fifth potential is approximately 24 volts below the reference potential.

13. The power supply system of claim 1 wherein a number of fuel cell stacks and a number of ultracapacitors in the first set of fuel cell systems are equal.

14. A power supply system, comprising:

a first voltage bus;

a first column of fuel cell systems electrically coupled in series to one another across the first voltage bus and operable to produce a voltage across the first voltage bus equal to a first voltage, where the number of fuel cell systems in the first column is equal to a number i and the number i is greater than 1;

a second column of fuel cell systems electrically coupled in series to one another across the first voltage bus in parallel with the first number of fuel cell systems, the second number of fuel cell systems operable to produce current at a first voltage across the first voltage bus, where the number of fuel cell systems in the second column is equal to the number i; and

a number of links electrically coupling each of the fuel cell systems in the second column in parallel with a respective one of the fuel cell systems in the first column,

wherein each fuel cell system comprises;

a fuel cell stack,

an electrical power storage device electrically coupled in parallel with the fuel cell stack,

limiting means for controlling a flow of current from the fuel cell stack to the electrical power storage device and the first voltage bus; and

bypass means for bypassing the limiting means electrically coupled in parallel with at least a portion of the limiting means.

15. The power supply system of claim 14, further comprising:

a third column of fuel cell systems electrically coupled in series to one another across the first voltage bus and operable to produce additional current at a voltage across the first voltage bus approximately equal to the first voltage, where the number of fuel cell systems in the third column is equal to the number i; and

a number of links electrically coupling each of the fuel cell systems in the third column to a respective one of the fuel cell systems in the second column.

16. The power supply system of claim 14, further comprising:

a second voltage bus;

a third column of fuel cell systems electrically coupled in series to one another across the second voltage bus and operable to produce current at a second voltage across the second voltage bus different from the first voltage, where the number of fuel cell systems in the third column is equal to a number j and the number j is less than the number i; and

a number of links electrically coupling each of the fuel cell systems in the third column to a respective one of the fuel cell systems in the second column.

17. The power supply system of claim 14, further comprising:

a second voltage bus;

a third column of fuel cell systems electrically coupled in series to one another across the second voltage bus and operable to produce current at a second voltage across the second voltage bus different from the first voltage, where the number of fuel cell systems in the third column is equal to a number j and the number j is less than the number i; and

a number of links electrically coupling each of the fuel cell systems in the third column to a respective one of the fuel cell systems in the second column;

a fourth column of fuel cell systems electrically coupled in series to one another across the second voltage bus and operable to produce additional current at approximately the second voltage across the second voltage bus different from the first voltage, where the number of fuel cell systems in the fourth column is equal to the number j; and

a number of links electrically coupling each of the fuel cell systems in the fourth column to a respective one of the fuel cell systems in the third column.

18. The power supply system of claim 14, further comprising:

a second voltage bus;

a third column of fuel cell systems electrically coupled in series to one another across the second voltage bus and operable to produce current at a second voltage across the second voltage bus different from the first voltage, where the number of fuel cell systems in the third column is equal to a number j and the number j is less than the number i; and

a number of links electrically coupling each of the fuel cell systems in the third column to a respective one of the fuel cell systems in the second column; and

a third voltage bus;

a fourth column of fuel cell systems electrically coupled in series to one another across the third voltage bus and operable to produce current at a third voltage across the third voltage bus different from the first and the second voltages, where the number of fuel cell systems in the fourth column is equal to a number k and the number k is less than the number j; and

a number of links electrically coupling each of the fuel cell systems in the fourth column to a respective one of the fuel cell systems in the third column.

19. The power supply system of claim 18 wherein the voltage across the first voltage bus is approximately 120 volts, the voltage across the second voltage bus is approximately 48 volts and the voltage across the third voltage bus is approximately 24 volts.

20. The power supply system of claim 18 wherein the number k is equal to one.

21. A power supply system, comprising:

a first set of fuel cell systems electrically coupled in series to one another and operable to produce a first voltage there across; and

a second set of fuel cell systems electrically coupled in series to one another and operable to produce a voltage there across, where each of the fuel cell systems in the second set of fuel cell systems is electrically coupled in parallel to a respective one of the fuel cell systems in the first set of fuel cell systems,

wherein each of the fuel cell systems comprises;

a fuel cell stack;

at least one ultracapacitor;

a charging current limiter electrically coupled in series with the at least one ultracapacitor to limit a charging current from the fuel cell stack to the ultracapacitor; and

a charging current limiter bypass device electrically coupled in parallel with the charging current limiter to provide a discharge path from the ultracapacitor bypassing the charging current limiter,

wherein the combination of the at least one ultracapacitor, the charging current limiter, and the charging current limiter bypass device is electrically coupled in parallel with the fuel cell stack.

22. The power supply system of claim 21 wherein each of the fuel cell systems further comprises:

a reverse charging diode electrically coupled in parallel with the least one ultracapacitor serially coupled to the parallel coupled charging current limiter and charging current limiter bypass device.

23. A power supply system, comprising:

a first voltage bus;

a first column of fuel cell systems electrically coupled in series to one another across the first voltage bus and operable to produce a voltage across the first voltage bus equal to a first voltage, where the number of fuel cell systems in the first column is equal to a number i and the number i is greater than 1;

a second column of fuel cell systems electrically coupled in series to one another across the first voltage bus in parallel with the first number of fuel cell systems, the second number of fuel cell systems operable to produce current at a first voltage across the first voltage bus, where the number of fuel cell systems in the second column is equal to the number i; and

a number of links electrically coupling each of the fuel cell systems in the second column in parallel with a respective one of the fuel cell systems in the first column,

wherein each fuel cell system comprises;

a fuel cell stack;

an electrical power storage device;

a means for controlling a flow of current from the fuel cell stack to the electrical power storage device and the first voltage bus, wherein the electrical power storage device is electrically coupled in series with the means for controlling the flow of current from the fuel cell stack; and

a charging current limiter bypass device electrically coupled in parallel with the means for controlling the flow of current from the fuel cell stack, wherein the charging current limiter bypass device is operable to provide a discharge path from the electrical power storage device bypassing the means for controlling the flow of current from the fuel cell stack, and

wherein the combination of the means for controlling the flow of current from the fuel cell stack, the charging current limiter bypass device, and the electrical power storage device is electrically coupled in parallel with the fuel cell stack.

24. The power supply system of claim 23 wherein each of the fuel cell systems further comprises:

a reverse charging diode electrically coupled in parallel with the least one ultracapacitor serially coupled to the parallel coupled charging current limiter and charging current limiter bypass device.