Fuel cell system

Patent metadata

Field	Value
Publication number	US-9941528-B2
Application number	US-201214342821-A
Country	US
Kind code	B2
Filing date	Aug 23, 2012
Priority date	Sep 7, 2011
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A fuel cell system includes a fuel cell module for generating electrical energy by electrochemical reactions of a fuel gas and an oxygen-containing gas, and a condenser for condensing water vapor in an exhaust gas discharged from the fuel cell module by heat exchange between the exhaust gas and a coolant to collect the condensed water and supplying the collected condensed water to the fuel cell module. The condenser includes an air cooling condenser using the oxygen-containing gas as the coolant and a water cooling condenser using hot water stored in a hot water tank as the coolant. A thermoelectric conversion mechanism for performing thermoelectric conversion by a temperature difference between the exhaust gas and the oxygen-containing gas is provided between the air cooling condenser and the water cooling condenser.

First claim

The invention claimed is:

1. A method of controlling a fuel cell system that comprises:
a fuel cell module for generating electrical energy by electrochemical reactions of a fuel gas and an oxygen-containing gas; and
a condenser for condensing water vapor in an exhaust gas discharged from the fuel cell module by heat exchange between the exhaust gas and a coolant to collect the condensed water and supplying the collected condensed water to the fuel cell module,
wherein the condenser includes an air cooling condensing mechanism using the oxygen-containing gas as the coolant and a water cooling condensing mechanism using hot water stored in a hot water storage unit as the coolant; and
a thermoelectric conversion mechanism for performing thermoelectric conversion by a temperature difference between the exhaust gas and the oxygen-containing gas is provided between the air cooling condensing mechanism and the water cooling condensing mechanism,
wherein the thermoelectric conversion mechanism includes a first thermoelectric converter provided adjacent to the air cooling condensing mechanism and a second thermoelectric converter provided adjacent to the water cooling condensing mechanism, and
wherein the fuel cell system further comprises:
a regulator valve for regulating separately the flow rate of the exhaust gas supplied to the air cooling condensing mechanism and the flow rate of the exhaust gas supplied to the water cooling condensing mechanism; and
a control device including: an electrical power comparator for comparing at least supplied electrical power with a predetermined demanded electrical power range; and a heat quantity comparator for comparing supplied heat quantity with a predetermined demanded heat quantity range, and
wherein the control device controls the regulator valve based on comparison results from the electrical power comparator and the heat quantity comparator,
wherein the volume of the first thermoelectric converter is larger than the volume of the second thermoelectric converter,
the method comprising:
determining by the electrical power comparator of the control device whether the supplied electrical power is within a range between a demanded lower limit electrical power and a demanded upper limit electrical power,
determining by the heat quantity comparator of the control device whether the supplied heat quantity is within a range between a demanded lower limit heat quantity and a demanded upper limit heat quantity,
wherein the control device, controlling the regulator valve,
increases the flow rate of the exhaust gas supplied to the air cooling condensing mechanism when the supplied electrical power is less than the demanded lower limit electrical power,
decreases the flow rate of the exhaust gas supplied to the air cooling condensing mechanism when the supplied electrical power is more than the demanded upper limit electrical power,
increases the flow rate of the exhaust gas supplied to the water cooling condensing mechanism when the supplied heat quantity is less than the demanded lower limit heat quantity, and
decreases the flow rate of the exhaust gas supplied to the water cooling condensing mechanism when the supplied heat quantity is more than the demanded upper limit heat quantity,

the first thermoelectric converter of the thermoelectric conversion mechanism increases or decreases the electrical energy in accordance with increase or decrease of the flow rate of the exhaust gas supplied to the air cooling condensing mechanism,
the second thermoelectric converter of the thermoelectric conversion mechanism increases or decreases the electrical energy in accordance with increase or decrease of the flow rate of the exhaust gas supplied to the water cooling condensing mechanism.

2. The method of controlling the fuel cell system according to claim 1 , wherein the thermoelectric conversion temperature of the first thermoelectric converter is higher than the thermoelectric conversion temperature of the second thermoelectric converter.

3. The method of controlling the fuel cell system according to claim 1 , wherein the hot water storage unit includes:
a hot water level detector for detecting a water level of the hot water; and
a hot water temperature detector for detecting a temperature of the hot water.

4. The method of controlling the fuel cell system according to claim 1 , wherein the condenser includes a water container for storing the condensed water and a condensed water level detector for detecting a water level of the condensed water in the water container.

5. The method of controlling the fuel cell system according to claim 1 , further comprising a fuel cell stack formed by stacking a plurality of fuel cells, the fuel cells each including an electrolyte electrode assembly and a separator stacked together, the electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between the anode and the cathode;
a heat exchanger for heating an oxygen-containing gas before the oxygen-containing gas is supplied to the fuel cell stack;
an evaporator for evaporating water to produce a mixed fuel of water vapor and a raw fuel chiefly containing hydrocarbon; and
a reformer for reforming the mixed fuel to produce the fuel gas.

6. The method of controlling the fuel cell system according to claim 1 , wherein the fuel cell module is a solid oxide fuel cell module.

Assignees

• Ogawa Tetsuya
• Honda Motor Co Ltd

Inventors

• Ogawa Tetsuya

Classifications

• H01M8/04619

  of fuel cell stacks · CPC title

• H01M8/04761

  of fuel cell exhausts · CPC title

• H01M8/04291 Primary

  Arrangements for managing water in solid electrolyte fuel cell systems (H01M8/04119 takes precedence) · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• Y02B90/16

  Cross-Sectional Technologies · mapped topic