Fuel cell system and its control method

Patent metadata

Field	Value
Publication number	US-9577271-B2
Application number	US-201414480971-A
Country	US
Kind code	B2
Filing date	Sep 9, 2014
Priority date	Jul 30, 2007
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

A fuel cell system includes; a fuel cell which generates electricity by using a fuel gas and an oxidant gas as reaction gases; current control means which controls current of a fuel cell; voltage control means which controls voltage of the fuel cell; and heat value control means which calculates a heat value required by the fuel cell system and decides a target current value of the current control means and a target voltage value of the voltage control means so as to generate the calculated necessary heat amount, thereby controlling the heat value. Thus, it is possible to supply a heat required for the fuel cell system without increasing the size of the fuel cell system.

First claim

The invention claimed is:

1. A fuel cell system comprising:
a fuel cell that generates electric power using a fuel gas and an oxidizing gas as reaction gases; and
a control unit configured to:
control a current of the fuel cell so that the current becomes a target current value;
control a voltage of the fuel cell so that the voltage becomes a target voltage value; and
control a heat generation quantity, by:
calculating a necessary heat quantity that is necessary for the fuel cell system at that point and a required output power of at least one of a motor or auxiliary machine of the fuel cell system at that point, and
determining the target current value and a target voltage so as to generate heat in the necessary required heat quantity and output power in the required output power.

2. The fuel cell system as set forth in claim 1 , further comprising:
a heating apparatus using the heat generated by the fuel cell as a heat source; and wherein
the necessary heat quantity includes a heating heat quantity necessary for the heating apparatus that is operating.

3. The fuel cell system as set forth in claim 1 , wherein the necessary heat quantity includes a warm-up heat quantity necessary for warming up the fuel cell.

4. The fuel cell system as set forth in claim 1 , wherein the necessary heat quantity includes a temperature-maintaining heat quantity necessary for maintaining the temperature of the fuel cell system at a predetermined temperature.

5. The fuel cell system as set forth in claim 1 , wherein the control unit performs control with low-efficiency power generation in which power generation efficiency is lower than that in high-efficiency power generation of the fuel cell.

6. The fuel cell system as set forth in claim 1 , wherein the control unit includes a voltage controlling section including DC/DC converter and a current controlling section including a reaction gas supplying section.

7. The fuel cell system as set forth in claim 1 , wherein
the control unit determines that the target current value=(Q+P)/Vmax, and the target voltage value=(Vmax*P)/(Q+P), where P is required output power for the fuel cell, Q is the necessary heat quantity, and Vmax is an electromotive force as a theoretical output voltage of the fuel cell.

Assignees

• Toyota Motor Co Ltd

Inventors

• Manabe Kota
• Imanishi Hiroyuki
• Ogawa Tomoya

Classifications

• H01M8/0488

  of fuel cell stacks · CPC title

• H01M8/04649

  of fuel cell stacks · CPC title

• H01M16/006

  of fuel cells with rechargeable batteries · CPC title

• H01M8/04902

  of the individual fuel cell · CPC title

• H01M8/04388

  of anode reactants at the inlet or inside the fuel cell · CPC title