Fuel cell system

• US 8,574,777 B2
• Filed: 12/05/2006
• Issued: 11/05/2013
• 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
• Primary Examiner(s): Ruddock, Ula C
• Assistant Examiner(s): Chmielecki, Scott J
• Application Number:
  US12/084,826
• Publication Number:
  US 20090148735A1
• Time in Patent Office: 2,527 Days
• Field of Search: 429/423, 429/429, 429/428, 429/430, 429/432, 429443-444
• US Class Current: 429/430
• 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, the first voltage conversion device being a booster converter;

an adjustment device which adjusts an amount of a reactant gas to be fed to the fuel cell; and

a controller programmed to;

operate 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 a warm-up operation of the fuel cell is required or an operation of recovering a catalyst activity of the fuel cell is required;

control 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 to raise a terminal voltage of the fuel cell to at least the driving voltage of the load; and

control the fuel cell voltage and fuel cell current to realize the shift of the operation point from the usual operation point to the low-efficiency operation point, while maintaining fuel cell power output constant, by lowering the fuel cell voltage with the booster converter and adjusting the amount of reactant gas fed to the fuel cell in order to control the fuel cell current.

2. 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.

3. The fuel cell system according to claim 2, 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.

4. 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.

5. The fuel cell system according to claim 4, 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.

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,

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.

7. A fuel cell system comprising:

a fuel cell;

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

a voltage and current sensor that measures the actual current and voltage of the fuel cell for comparison with initial cell characteristic data to determine an operation point 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, the first voltage conversion device being a booster converter;

an adjustment device which adjusts an amount of a reactant gas to be fed to the fuel cell; and

a controller programmed to;

operate 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 a warm-up operation of the fuel cell is required or an operation of recovering a catalyst activity of the fuel cell is required in a case where a voltage in the initial cell characteristic data equals the actual voltage and the actual current is less than a current in the initial cell characteristic data and a predetermined value combined;

control 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 to raise a terminal voltage of the fuel cell to at least the driving voltage of the load; and

control the fuel cell voltage and fuel cell current to realize the shift of the operation point from the usual operation point to the low-efficiency operation point, while maintaining fuel cell power output constant, by lowering the fuel cell voltage with the booster converter and adjusting the amount of reactant gas fed to the fuel cell in order to control the fuel cell current.