Fuel cell system

Patent metadata

Field	Value
Publication number	US-11508976-B2
Application number	US-201916516617-A
Country	US
Kind code	B2
Filing date	Jul 19, 2019
Priority date	Jul 26, 2018
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

A fuel cell system includes a fuel cell, an anode gas supply system, an anode gas circulatory system, a cathode gas supply-discharge system, a gas-liquid discharge passage, a gas-liquid discharge valve configured to open and close the gas-liquid discharge passage, a flow-rate acquisition portion, and a controlling portion. After the controlling portion instructs the gas-liquid discharge valve to be opened, the controlling portion executes a normal-abnormality determination such that, when a discharge-gas flow rate of anode gas is a predetermined normal reference value or more, the controlling portion determines that the gas-liquid discharge valve is opened normally, and when the discharge-gas flow rate is lower than the normal reference value, the controlling portion determines that the gas-liquid discharge valve is not opened normally.

First claim

What is claimed is:

1. A fuel cell system comprising:
a fuel cell;
an anode gas supply system configured to supply anode gas to the fuel cell, the anode gas supply system including an anode gas supply passage through which the anode gas flows toward the fuel cell;
an anode gas circulatory system configured to circulate anode offgas discharged from the fuel cell to the anode gas supply passage, the anode gas circulatory system including
an anode gas circulation passage through which the anode offgas flows toward the anode gas supply passage, and
a gas-liquid separator provided in the anode gas circulation passage and configured to separate liquid water from the anode offgas;
a cathode gas supply-discharge system including
a cathode gas supply passage configured to supply cathode gas to the fuel cell, and
a cathode gas discharge passage through which cathode offgas discharged from the fuel cell is discharged to an outside of the fuel cell system;
a gas-liquid discharge passage connected to the gas-liquid separator;
a gas-liquid discharge valve provided in the gas-liquid discharge passage and configured to open and close the gas-liquid discharge passage;
a pressure sensor configured to measure a pressure inside the anode gas supply passage;
a temperature acquisition portion configured to acquire an environmental temperature of the fuel cell system,
a water-storage-amount acquisition portion configured to acquire an amount of the liquid water accumulated in the gas-liquid separator; and
a controlling portion configured to execute an operation determination process including a normal-abnormality determination on whether the gas-liquid discharge valve is opened normally or not, and programmed to:
calculate a discharge-gas flow rate of the anode offgas discharged from the gas-liquid separator by use of a change of the pressure measured by the pressure sensor,
in a case of receiving an activation instruction to activate the fuel cell system, when the environmental temperature is a freezing point or less, execute a below-freezing starting process by controlling the anode gas supply system to supply the anode gas to the fuel cell and instructing the gas-liquid discharge valve to be opened,
after instructing the gas-liquid discharge valve to be opened in the below-freezing starting process, execute the normal-abnormality determination,
when the calculated discharge-gas flow rate of the anode offgas is a predetermined normal reference value or more, determine that the gas-liquid discharge valve is opened normally, and when the calculated discharge-gas flow rate of the anode offgas is lower than the predetermined normal reference value, determine that the gas-liquid discharge valve is not opened normally,
after determining that the gas-liquid discharge valve is not opened normally, execute a warm-up operation to raise a temperature of the fuel cell,
execute a restoration determination on whether or not an operation of the gas-liquid discharge valve is restored to normal, at least during execution of the warm-up operation or after the execution of the warm-up operation, the restoration determination being executed, after instructing the gas-liquid discharge valve to be opened, such that when the calculated discharge-gas flow rate of the anode offgas is a predetermined restoration reference value or more, it is determined that the operation of the gas-liquid discharge valve is restored to normal, and when the calculated discharge-gas flow rate of the anode offgas is lower than the predetermined restoration reference value, it is determined that the operation of the gas-liquid discharge valve is not restored to normal,
wherein the controlling portion is further programmed to:
in a normal operation state of the fuel cell system where the gas-liquid discharge valve is opened normally, when the amount of the liquid water accumulated in the gas-liquid separator reaches a predetermined first liquid water amount or more, execute a normal gas discharge process by instructing the gas-liquid discharge valve to be opened,
in a pre-restoration state of the fuel cell system before the operation of the gas-liquid discharge valve is restored to normal, when the amount of the liquid water accumulated in the gas-liquid separator reaches at least a second liquid water amount smaller than the first liquid water amount, execute a restoration gas discharge process by instructing the gas-liquid discharge valve to be opened,
execute the restoration determination after instructing the gas-liquid discharge valve to be opened in the restoration gas discharge process,
in a case where the restoration determination is performed, execute at least any of the following processes:
a first pre-process of increasing a pressure of the anode gas to be supplied to the fuel cell to be higher than a pressure of the anode gas to be supplied to the fuel cell during the execution of the normal gas discharge process,
a second pre-process of decreasing a flow rate of the anode offgas to be circulated from the anode gas circulation passage to the anode gas supply passage to be lower than a flow rate of the anode offgas to be circulated from the anode gas circulation passage to the anode gas supply passage during the execution of the normal gas discharge process; and
a third pre-process of decreasing a current value of the fuel cell to be smaller than a current value of the fuel cell during the execution of the normal gas discharge process.

2. The fuel cell system according to claim 1 , further comprising a water-storage-amount acquisition portion configured to acquire an amount of the liquid water accumulated in the gas-liquid separator, wherein:
in a normal operation state of the fuel cell system where the gas-liquid discharge valve is opened normally, in a case where the amount of the liquid water accumulated in the gas-liquid separator is a predetermined first liquid water amount or more, the controlling portion executes a normal gas discharge process by controlling the anode gas supply system to supply the anode gas to the fuel cell and instructing the gas-liquid discharge valve to be opened; and
a pressure of the anode gas to be supplied to the fuel cell in the operation determination process is higher than a pressure of the anode gas to be supplied to the fuel cell in the normal gas discharge process.

3. The fuel cell system according to claim 2 , wherein:
the cathode gas supply-discharge system further includes a compressor provided in the cathode gas supply passage;
the gas-liquid discharge passage is connected to the cathode gas discharge passage; and
the controlling portion controls an operation of the compressor so that a flow rate of the cathode gas flowing through the cathode gas discharge passage in the operation determination process is larger than a flow rate of the cathode gas flowing through the cathode gas discharge passage in the normal gas discharge process.

4. The fuel cell system according to claim 1 , wherein:
the cathode gas supply-discharge system includes a compressor configured to send the cathode gas toward the cathode gas discharge passage;
the gas-liquid discharge passage is connected to the cathode gas discharge passage; and
the controlling portion controls an operation of the compressor so that a flow rate of the cathode gas flowing through the cathode gas discharge passage at a time when the restoration determination is executed is larger than a flow rate of the cathode gas flowing through the cathode gas discharge passage in the normal gas discharge process.

5. The fuel cell system according to claim 1 , wherein:
in a case where an accumulated amount of the anode offgas discharged from the gas-liquid discharge passage within a predetermined period is a predetermined reference accumulated amount or more

Assignees

• Toyota Motor Co Ltd

Inventors

• Yamanaka Tomio
• Ishikawa Tomotaka
• Ogawa Tomohiro
• Oya Ryosuke
• Matsuo Junichi

Classifications

• H01M8/04156 Primary

  with product water removal · CPC title

• H01M8/04776

  at auxiliary devices, e.g. reformer, compressor, burner · CPC title

• Y02E60/50

  Fuel cells · CPC title

• Y02T90/40

  Application of hydrogen technology to transportation, e.g. using fuel cells · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title