Power supply system

• US 20050019621A1
• Filed: 07/23/2004
• Published: 01/27/2005
• Est. Priority Date: 07/23/2003
• Status: Active Grant

• Current Assignee: Japan Research Institute Limited (Sumitomo Mitsui Financial Group Incorporated)
• Original Assignee: Japan Research Institute Limited (Sumitomo Mitsui Financial Group Incorporated)
• Inventors: Inoue, Makoto, Ikuma, Hitoshi
• Granted Patent: US 6,981,379 B2
• Time in Patent Office: Days
• US Class Current: 60/706
• CPC Class Codes: H01M 8/04246 Short circuiting means for defective fuel cells detection of defective fuel cells H01M8/04664, methods for shunting fuel cells H01M8/04955
• CPC Class Codes: H01M 8/04604 Power, energy, capacity or load
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04671 of the individual fuel cell
• CPC Class Codes: H01M 8/04686 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04925 Power, energy, capacity or load
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

To provide a power supply system that allows the current maximum power generation capability to be easily recognized, this power supply system includes a plurality of fuel cells for generating power and supplying the power to loads; a performance storage section for storing a maximum power value indicating a maximum value of a power generation ability of each fuel cell; a test device for sequentially performing maximum power generation testing on at least one of the fuel cells at a predetermined time interval; an update section for updating the maximum power value of each fuel cell, the maximum power value being stored on the performance storage section, according to a result of the performance test; a power-generation-amount detection section for detecting the total of amounts of power generated and supplied by the fuel cells to the loads; and a surplus-power determination section for determining surplus power, which can be excessively generated by the power supply system, at the predetermined time interval based on a difference between the total of the maximum power values stored on the performance storage section and the total of amounts of the power generated.

Claims

1. A power supply system that supplies power to loads, comprising:

a plurality of fuel cells for generating electric power and supplying the electric power to the loads;

a performance storage section for storing a maximum power value indicating a maximum value of a power generation ability of each of said fuel cells;

a test device for sequentially performing maximum power generation testing on at least one of said fuel cells at a predetermined time interval;

an update section for updating the maximum power value of each of said fuel cells according to a result of the performance test, wherein the maximum power value is stored on said performance storage section;

a power-generation-amount detection section for detecting a total of amounts of power generated and supplied by said fuel cells to the loads; and

a surplus-power determination section for determining surplus power, which can be excessively generated by the power supply system, at the predetermined time interval based on a difference between a total of the maximum power values stored on said performance storage section and the total of amounts of the generated power.

2. The power supply system as claimed in claim 1, further comprising

a selection section for selecting one or more fuel cells including said fuel cell to be tested by said test device from said plurality of fuel cells, so that the total of the maximum power values of said selected fuel cells is greater than the demand of the loads and the number of selected fuel cells may be a minimum, to cause said selected fuel cell to generate power;

and

a selection change section for sequentially changing said fuel cell selected by said selection section at the predetermined time interval to cause said test device to test all said fuel cells.

3. The power supply system as claimed in claim 2, wherein said selection section preferentially selects said fuel cell having large maximum power value as well as said fuel cell to be tested.

4. The power supply system as claimed in claim 2, wherein said selection section does not select said fuel cell when the maximum power value of said fuel cell becomes less than a predetermined value.

5. The power supply system as claimed in claim 4, further comprising a request receiving section for receiving a request for power from outside in a case of emergency, wherein,

said selection section causes said fuel cell, of which the maximum power value became less than the predetermined value, to generate power and supplies the generated power to outside only in the case of emergency.

6. The power supply system as claimed in claim 1, further comprising a control section, wherein, when a request requesting a power less than the surplus power is received from outside, said control section causes said fuel cells to generate power according to the request from the outside and to supply the power to outside.

7. The power supply system as claimed in claim 1, wherein said surplus-power determination section calculates a probability of shortage of the power to be supplied to the loads based on the surplus power, and an alarm indicating the power shortage is issued to outside when the probability of power shortage to be supplied to the loads exceeds a predetermined value.

8. The power supply system as claimed in claim 7, wherein said surplus-power determination section calculates the probability of shortage of the power to be supplied to the loads based on power transition data, which is an estimate of transition of demand of the loads.

9. The power supply system as claimed in claim 7, wherein said performance storage section further stores a failure probability of each fuel cell, and

said surplus-power determination section calculates the probability of shortage of the power to be supplied to the loads based on the failure probability.

10. The power supply system as claimed in claim 7, further comprising a load control section, wherein, when power is supplied to said plurality of loads and the probability of power shortage is greater than or equal to a predetermined value, said load control section acts so as not to supply the power to predetermined non-significant loads among the plurality of loads.

11. The power supply system as claimed in claim 8, further comprising a load control section, wherein, when power is supplied to said plurality of loads and the probability of power shortage is greater than or equal to a predetermined value, said load control section acts so as not to supply the power to predetermined non-significant loads among the plurality of loads.

12. The power supply system as claimed in claim 9, further comprising a load control section, wherein, when power is supplied to said plurality of loads and the probability of power shortage is greater than or equal to a predetermined value, said load control section acts so as not to supply the power to predetermined non-significant loads among the plurality of loads.

13. The power supply system as claimed in one of claim 7, further comprising a cell switch section for splitting said plurality of fuel cells into a high-reliability cell group of which maximum power value is greater than or equal to a predetermined value and a low-reliability cell group of which maximum power value is less than the predetermined value, to supply power to-the plurality of loads;

and

a load control section for connecting predetermined significant loads among the plurality of loads to the high-reliability cell group and connecting non-significant loads other than the significant loads to the low-reliability cell group.

14. The power supply system as claimed in one of claim 7, further comprising a cell switch section for splitting said plurality of fuel cells into a high-reliability cell group of which maximum power value is greater than or equal to a predetermined value and a low-reliability cell group of which maximum power value is less than the predetermined value, to supply power to the plurality of loads;

and

a load control section for connecting predetermined significant loads among the plurality of loads to the high-reliability cell group and connecting non-significant loads other than the significant loads to the low-reliability cell group.

15. The power supply system as claimed in one of claim 7, further comprising a cell switch section for splitting said plurality of fuel cells into a high-reliability cell group of which maximum power value is greater than or equal to a predetermined value and a low-reliability cell group of which maximum power value is less than the predetermined value, to supply power to the plurality of loads;

and

a load control section for connecting predetermined significant loads among the plurality of loads to the high-reliability cell group and connecting non-significant loads other than the significant loads to the low-reliability cell group.

16. The power supply system as claimed in claim 13, wherein, when the probability of power shortage exceeds a predetermined value, said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group;

and

when said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group, said load control section connects predetermined significant loads among the plurality of loads to the high-reliability cell group and connects non-significant loads other than the significant loads to the low-reliability cell group.

17. The power supply system as claimed in claim 13, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, the cell switch section causes said fuel cell, which has the greatest maximum power generation capacity among said fuel cells belonging to the low-reliability cell group, to belong to the high-reliability cell group.

18. The power supply system as claimed in claim 13, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, said load control section connects the predetermined load, which has a lowest significance among the significant loads, to the low-reliability cell group as the non-significant loads.

19. The power supply system as claimed in claim 13, further comprising:

a high-reliability power network, to which the high-reliability cell group and the significant loads are connected, for supplying power generated by the high-reliability cell group to the significant loads; and

a low-reliability power network, to which the low-reliability cell group and the non-significant loads are connected, for supplying power generated by the low-reliability cell group to the non-significant loads.

20. The power supply system as claimed in claim 14, wherein, when the probability of power shortage exceeds a predetermined value, said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group;

and

when said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group, said load control section connects predetermined significant loads among the plurality of loads to the high-reliability cell group and connects non-significant loads other than the significant loads to the low-reliability cell group.

21. The power supply system as claimed in claim 14, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, the cell switch section causes said fuel cell, which has the greatest maximum power generation capacity among said fuel cells belonging to the low-reliability cell group, to belong to the high-reliability cell group.

22. The power supply system as claimed in claim 14, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, said load control section connects the predetermined load, which has a lowest significance among the significant loads, to the low-reliability cell group as the non-significant loads.

23. The power supply system as claimed in claim 14, further comprising:

a high-reliability power network, to which the high-reliability cell group and the significant loads are connected, for supplying power generated by the high-reliability cell group to the significant loads; and

a low-reliability power network, to which the low-reliability cell group and the non-significant loads are connected, for supplying power generated by the low-reliability cell group to the non-significant loads.

24. The power supply system as claimed in claim 15, wherein, when the probability of power shortage exceeds a predetermined value, said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group;

and

when said cell switch section splits said plurality of fuel cells into the high-reliability cell group and the low-reliability cell group, said load control section connects predetermined significant loads among the plurality of loads to the high-reliability cell group and connects non-significant loads other than the significant loads to the low-reliability cell group.

25. The power supply system as claimed in claim 15, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, the cell switch section causes said fuel cell, which has the greatest maximum power generation capacity among said fuel cells belonging to the low-reliability cell group, to belong to the high-reliability cell group.

26. The power supply system as claimed in claim 15, wherein, when a total demand of the significant loads is greater than a total power generation capacity of the high-reliability cell group, said load control section connects the predetermined load, which has a lowest significance among the significant loads, to the low-reliability cell group as the non-significant loads.

27. The power supply system as claimed in claim 15, further comprising:

a high-reliability power network, to which the high-reliability cell group and the significant loads are connected, for supplying power generated by the high-reliability cell group to the significant loads; and

a low-reliability power network, to which the low-reliability cell group and the non-significant loads are connected, for supplying power generated by the low-reliability cell group to the non-significant loads.