FUEL CELL SYSTEM

• US 20080182144A1
• Filed: 01/24/2008
• Published: 07/31/2008
• Est. Priority Date: 01/29/2007
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: SAEKI, Hibiki, Shirasaka, Takuya
• Granted Patent: US 8,349,508 B2
• Time in Patent Office: Days
• US Class Current: 429/23
• 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 8/04228 during shut-down
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04567 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04597 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• 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

When the output of a fuel cell starts to decrease, in consideration of the increase in the power generation efficiency, an instruction for the output of the fuel cell undergoes a smoothing process to gradually decrease the output, and excessive electric power generated during a period in which the power generation efficiency is high is used for charging a battery. While the output of the fuel cell is increasing, the power generation efficiency of the fuel cell is low. Thus, assisting electrical energy from the battery is increased. In this manner, the power generation output when the power generation efficiency of the fuel cell is low is reduced from a high power generation output to a low power generation output to achieve improvement in the average power generation efficiency.

Claims

1. A fuel cell system comprising:

a fuel cell operated for power generation by reaction of reactant gases supplied to said fuel cell; and

an output control device for controlling the supply of the reactant gases and electrical current collected from said fuel cell;

said output control device comprising;

means for calculating a target output of said fuel cell in correspondence with an output required for a load;

means for determining whether the required output is increased or decreased; and

means for limiting an output decreasing speed by gradually decreasing the target output when said determining means determines that the required output is decreased.

2. A fuel cell system according to claim 1, further comprising an energy storage provided in parallel with said load, said energy storage being charged by an excessive output when the target output is decreased gradually, and

said output control device further comprising means for relaxing or releasing a limit of the output decreasing speed when there is a possibility that the excessive output may exceed an allowable limit of electric power for continuously charging said energy storage.

3. A fuel cell system according to claim 2, wherein said load is an electric motor, and said output control device further comprises means for preferentially charging said energy storage using regenerative electric power by said electric motor when decrease in the required output is caused by deceleration, and adopting the limit of the output decreasing speed by the output decreasing speed limit relaxing means in preference to a limit of the regenerative electric power, when there is a possibility that the total of the excessive output and the regenerative electric power may exceed the allowable limit of electric power for continuously charging said energy storage.