Solid oxide fuel cell system

Patent metadata

Field	Value
Publication number	US-11127963-B2
Application number	US-201916280041-A
Country	US
Kind code	B2
Filing date	Feb 20, 2019
Priority date	Mar 15, 2018
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

Abstract

A SOFC system includes: a fuel cell stack; a reformer; an air supplier: a combustor; and a controller. In a stop control of the above system, the controller calculates an average of ratios of the air to the raw material supplied to the reformer as a first average, in a case in which a molar fraction of a hydrogen component in the anode off-gas is higher than a molar fraction of a raw material component in the anode off-gas, and calculates the average of the ratios of the air to the raw material supplied to the reformer as a second average, in a case in which the molar fraction of the hydrogen component in the anode off-gas is lower than the molar fraction of the raw material component in the anode off-gas. The controller controls the air supplier so that the first average is higher than the second average.

First claim

What is claimed is:

1. A solid oxide fuel cell system comprising:
a fuel cell stack generating a power using a fuel gas and air;
a reformer generating the fuel gas by reforming a raw material;
an air supplier supplying the air to the fuel cell stack:
a combustor combusting an anode off-gas and a cathode off-gas each discharged from the fuel cell stack;
a controller,
wherein in a stop control of the solid oxide fuel cell system in which the fuel gas and the air are continuously supplied to the fuel cell stack after power generation is stopped,
the controller is programmed to calculate an average value of ratios of the air to the raw material supplied to the reformer as a first average value, when a molar fraction of a hydrogen component in the anode off-gas is higher than a molar fraction of a raw material component in the anode off-gas,
the controller is programmed to calculate an average value of the ratios of the air to the raw material supplied to the reformer as a second average value, when the molar fraction of the hydrogen component in the anode off-gas is lower than the molar fraction of the raw material component in the anode off-gas, and
the controller is programmed to control the air supplier so that the first average value is higher than the second average value; and

a temperature detector detecting a temperature of the reformer, wherein in the stop control, the controller is programmed to control the air supplier based on the temperature detected by the temperature detector,
wherein in the stop control, the controller is programmed to control the air supplier to decrease the ratio of the air to the raw material supplied to the reformer when calculating the first average value and the second average value, and wherein the controller is programmed to control the air supplier as the temperature detected by the temperature detector is decreased.

2. The solid oxide fuel cell system according to claim 1 , wherein the temperature detector is located in or adjacent to the reformer.

3. The solid oxide fuel cell system according to claim 1 , wherein the temperature detector is located in the fuel cell stack or adjacent thereto.

4. The solid oxide fuel cell system according to claim 1 , further comprising
a raw material supplier supplying the raw material to the reformer,
wherein in the stop control, the controller is programmed to control the raw material supplier so as to set a supply amount of the raw material supplied to the reformer to a flow rate corresponding to a calorific value of 300 W or more.

5. The solid oxide fuel cell system according to claim 1 , further comprising
a water supplier supplying water to the reformer,
wherein in the stop control, the controller is programmed to control the water supplier so as to set S/C in the reformer to 2.0 or more.

6. The solid oxide fuel cell system according to claim 1 , further comprising
an ignition device igniting the combustor,
wherein in the stop control, the controller is programmed to control the ignition device to ignite the combustor when the temperature detected by the temperature detector is decreased by a predetermined value or more in a predetermined time or at predetermined time intervals.

7. The solid oxide fuel cell system according to claim 1 , wherein the combustor is a diffusion combustor.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kakuwa Takashi
• Onuma Shigenori
• Mikami Yuichi

Classifications

• H01M8/0612

  from carbon-containing material · CPC title

• H01M8/04955 Primary

  Shut-off or shut-down of fuel cells · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M8/04753 Primary

  of fuel cell reactants · CPC title