Fuel cell control unit for limiting power output

• US 8,349,508 B2
• Filed: 01/24/2008
• Issued: 01/08/2013
• Est. Priority Date: 01/29/2007
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Saeki, Hibiki, Shirasaka, Takuya
• Primary Examiner(s): WALKER, KEITH D
• Application Number:
  US12/019,267
• Publication Number:
  US 20080182144A1
• Time in Patent Office: 1,811 Days
• Field of Search: None
• US Class Current: 429/430
• 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 control unit the supply of the reactant gases and power generation output of said fuel cell, said output control device comprising;

means for calculating a target output base value of said fuel cell, wherein the calculation is performed in correspondence with deceleration or acceleration by operation of an accelerator pedal for driving a motor;

means for determining whether the target output base value is increased or decreased; and

means for limiting a decreasing speed of the power generation output, wherein the limitation is performed by putting a limit on a rate of the decreasing speed of the power generation output when the target output base value is decreased, such that the power generation decrease occurs linearly or with a first order lag, with respect to time; and

further comprising an energy storage provided in parallel with said motor, said energy storage being charged by an excessive output when the power generation output is decreased, the excessive output being a difference between the target output base value and the power generation output, and

said output control device further comprising means for relaxing or releasing the limit of the decreasing speed of the power generation output, wherein the relaxation or release of the limit is performed when the excessive output exceeds an allowable limit of electric power for continuously charging said energy storage.

2. 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 control unit the supply of the reactant gases and power generation output of said fuel cell, said output control device comprising;

means for calculating a target output base value of said fuel cell, wherein the calculation is performed in correspondence with deceleration or acceleration by operation of an accelerator pedal for driving a motor;

means for determining whether the target output base value is increased or decreased; and

means for limiting a decreasing speed of the power generation output, wherein the limitation is performed by putting a limit on a rate of the decreasing speed of the power generation output when the target output base value is decreased, such that the power generation decrease occurs linearly or with a first order lag, with respect to time;

wherein said output control device further comprises means for adjusting the limit,

wherein charging said energy storage when a decrease in the power generation output is caused by deceleration, the limit adjusting means gives preference to regenerative electric power by said motor over the excessive output charging said energy storage, and

wherein the limit adjusting means relaxes or releases the limit of the decreasing speed of the power generation output before limiting the regenerative electric power, when the total of the excessive output and the regenerative electric power exceeds the allowable limit of electric power for continuously charging said energy storage.