Fuel cell system and its control method

• US 9,577,271 B2
• Filed: 09/09/2014
• Issued: 02/21/2017
• Est. Priority Date: 07/30/2007
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Manabe, Kota, Imanishi, Hiroyuki, Ogawa, Tomoya
• Primary Examiner(s): WOLLSCHLAGER, JEFFREY MICHAEL
• Application Number:
  US14/480,971
• Publication Number:
  US 20150064589A1
• Time in Patent Office: 896 Days
• US Class Current: 1/1
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 8/04037 Electrical heating
• CPC Class Codes: H01M 8/04268 Heating of fuel cells during the start-up of the fuel cells
• CPC Class Codes: H01M 8/04335 of cathode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04358 of the coolant
• CPC Class Codes: H01M 8/04365 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04388 of anode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04395 of cathode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04492 Humidity; Ambient humidity; Water content
• 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 8/04649 of fuel cell stacks
• CPC Class Codes: H01M 8/04731 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04873 of the individual fuel cell
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/04902 of the individual fuel cell
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• 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

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.

Claims

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.