Fuel cell system

• US 8,221,924 B2
• Filed: 09/12/2007
• Issued: 07/17/2012
• Est. Priority Date: 10/18/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kajiwara, Shigeto
• Primary Examiner(s): Ruddock, Ula C
• Assistant Examiner(s): Marks, Jacob
• Application Number:
  US12/295,130
• Publication Number:
  US 20090162710A1
• Time in Patent Office: 1,770 Days
• Field of Search: 429/429
• US Class Current: 429/429
• CPC Class Codes: H01M 8/04119 with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
• CPC Class Codes: H01M 8/04365 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/0441 of cathode exhausts
• CPC Class Codes: H01M 8/04507 of cathode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04552 of the individual fuel cell
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04656 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04723 of the coolant
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell system includes: a fuel cell stack for generating electric power by receiving supply of a reaction gas; an air compressor for scavenging water remaining in the fuel cell stack when power generation is stopped; a rechargeable battery for supplying electric power to the air compressor for operation thereof; and a controller for estimating an amount of water remaining in the fuel cell stack based on an alternating-current impedance of the fuel cell stack, estimating a target SOC for charging the rechargeable battery with electric power required for scavenging the amount of water, and controlling charge and discharge so that an SOC of the rechargeable battery agrees with the target SOC.

Claims

1. A fuel cell system comprising:

a fuel cell stack for generating electric power by receiving supply of a reaction gas;

a scavenging device for scavenging water remaining in the fuel cell stack when power generation is stopped;

an electric storage device for supplying electric power to the scavenging device for operation thereof;

a control system programmed to;

estimate an amount of water remaining in the fuel cell stack based on an alternating-current impedance of the fuel cell stack;

estimate a target SOC for charging the electric storage device with electric power required for scavenging the amount of water; and

control charge and discharge of the electric storage device before the fuel cell system is required to stop power generation so that an SOC of the electric storage device agrees with the target SOC.

2. A fuel cell system comprising:

a fuel cell stack for generating electric power by receiving supply of a reaction gas;

a scavenging device for scavenging water remaining in the fuel cell stack when power generation is stopped;

an electric storage device for supplying electric power to the scavenging device for operation thereof;

a control system programmed to;

estimate an amount of water remaining in the fuel cell stack based on a water balance calculation of the fuel cell stack;

estimate a target SOC for charging the electric storage device with electric power required for scavenging the amount of water; and

control charge and discharge of the electric storage device before the fuel cell system is required to stop power generation so that an SOC of the electric storage device agrees with the target SOC.