Fuel Cell System

• US 20090148735A1
• Filed: 12/05/2006
• Published: 06/11/2009
• Est. Priority Date: 12/07/2005
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Manabe, Kota, Horio, Kimihide
• Granted Patent: US 8,574,777 B2
• Time in Patent Office: Days
• US Class Current: 429/412
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0053 relating to fuel cells
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 58/31 for starting of fuel cells
• CPC Class Codes: B60L 58/33 by cooling
• CPC Class Codes: B60L 58/34 by heating
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 4/86 Inert electrodes with catalytic activity, e.g. for fuel cells
• CPC Class Codes: H01M 8/04 Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
• 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 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04888 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2457 with both reactants being gaseous or vaporised
• 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

There is disclosed a fuel cell system capable of stably operating auxiliary devices driven at a high voltage and the like, even in a case where a poisoned electrode catalyst is recovered or a fuel cell is warmed up. On detecting that the electrode catalyst is poisoned, a controller derives a target operation point which is sufficient for recovering an activity of the poisoned electrode catalyst. Then, shift of the operation point from a usual operation point to a low-efficiency operation point is realized so that an output power is held to be constant.

Claims

1. A fuel cell system comprising:

a fuel cell;

a load which operates owing to a power of the fuel cell;

a first voltage conversion device which is provided between the fuel cell and the load and which converts an output of the fuel cell into a voltage to supply the voltage to the load;

an operation control device for operating the fuel cell at a low-efficiency operation point having a power loss larger than that of a usual operation point in a case where predetermined conditions are satisfied; and

a voltage conversion control device for controlling a voltage converting operation of the first voltage conversion device based on the operation point of the fuel cell and a driving voltage of the load.

2. The fuel cell system according to claim 1, wherein the first voltage conversion device is a booster converter to raise a terminal voltage of the fuel cell, and

the voltage conversion control device allows the booster converter to raise the terminal voltage of the fuel cell corresponding to the operation point to at least the driving voltage of the load.

3. The fuel cell system according to claim 1, wherein when a warm-up operation of the fuel cell is required or an operation of recovering a catalyst activity of the fuel cell is required, the fuel cell is operated at the low-efficiency operation point.

4. The fuel cell system according to claim 1, further comprising:

a bypass device for bypassing the booster converter to supply an output current of the fuel cell to the load, while the fuel cell operates at the usual operation point.

5. The fuel cell system according to claim 4, wherein the bypass device is a diode in which an anode is connected to an input side of the booster converter and in which a cathode is connected to an output side of the booster converter.

6. The fuel cell system according to claim 1, further comprising:

a chargeable/dischargeable power accumulation device; and

a second voltage conversion device which converts the voltage between the power accumulation device and the load.

7. The fuel cell system according to claim 6, wherein the second voltage conversion device is a booster converter which raises a discharge voltage of the power accumulation device, or a converter which raises or lowers the discharge voltage.

11. The fuel cell system according to claim 1, wherein the operation control device shifts the operation point in a state in which an output power is held to be constant.

12. The fuel cell system according to claim 1, further comprising:

a chargeable/dischargeable power accumulation device; and

a second voltage conversion device which converts the voltage between the power accumulation device and the load,

wherein the voltage conversion control device controls a voltage converting operation of the first voltage conversion device and a voltage converting operation of the second voltage conversion device in accordance with the driving voltage of the load.

13. The fuel cell system according to claim 12, wherein the voltage conversion control means controls a voltage converting operation of the first voltage conversion device in accordance with the driving voltage of the load, and controls a voltage converting operation of the second voltage conversion device in accordance with the converted voltage obtained by the voltage converting operation.

8. A fuel cell system comprising:

a fuel cell which generates a power by use of a fuel gas and an oxidizing gas;

a load connected to the fuel cell;

a chargeable/dischargeable power accumulation device interposed between the fuel cell and the load;

a voltage conversion device which controls a terminal voltage of the fuel cell to determine operation points of the fuel cell and the power accumulation device;

an operation control device for operating the fuel cell at a low-efficiency operation point having a power loss larger than that of a usual operation point in a case where predetermined conditions are satisfied; and

a change device for allowing the voltage conversion device to adjust the terminal voltage of the fuel cell, and controlling an amount of the oxidizing gas to be supplied to the fuel cell to adjust an output current of the fuel cell, thereby changing the operation point of the fuel cell.

9. A fuel cell system comprising:

a fuel cell which generates a power by use of a fuel gas and an oxidizing gas;

an inhibition device for inhibiting supply of the oxidizing gas in a case where predetermined conditions are satisfied;

a first determination device for determining a target power of the fuel cell at a time when the supply of the oxidizing gas is inhibited;

a second determination device for determining a target current based on the target power and an actually measured voltage of the fuel cell; and

a third determination device for feeding back a deviation between the target current and an actually measured current of the fuel cell to a change amount of the actually measured voltage of the fuel cell to determine a target voltage value.

10. The fuel cell system according to claim 9, wherein the inhibition device stops the supply of the oxidizing gas in a case where an output voltage of the fuel cell is lowered from the vicinity of an opened circuit voltage to a voltage at a low-efficiency operation point, and

the first determination device determines the target power of the fuel cell at a time when the supply of the oxidizing gas is stopped.