Fuel cell system and activation method of fuel cell

Abstract

A fuel cell system includes a fuel cell which generates electric power using supplied reactive gases; a load control device for controlling a load applied to the fuel cell; a voltage measuring device for measuring a voltage generated by the fuel cell; a fuel cell driving control device for controlling at least a supply of the reactive gases to the fuel cell; and a voltage variation rate obtaining device for obtaining a rate of variation in the voltage generated by the fuel cell when the load is varied. The fuel cell driving control device is controlled based on the rate of variation in the generated voltage obtained by the voltage variation rate obtaining device. The voltage variation rate being obtained when the generated voltage increases. The load being varied by applying momentarily a load to the fuel cell when the voltage variation rate is obtained.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the fuel cell system according to an embodiment of the present invention;

FIG. 2 is a chart showing a correlation between the load variation and the generated voltage with respect to the fuel cell;

FIG. 3 is a flowchart showing an activation control operation of the fuel cell;

FIG. 4 is a map used for computing the amount and pressure of the supplied reactive gases;

FIG. 5 is a map used for computing an applicable electric current;

FIG. 6 is a chart showing a correlation between the load variation and the generated voltage with respect to the fuel cell; and

FIG. 7 is a flowchart showing an example of the stopping control operation of the fuel cell.

Claims

1. A fuel cell system comprising: a fuel cell which generates electric power using reactive gases supplied thereto;a load control device for controlling a load applied to the fuel cell;a voltage measuring device for measuring a voltage generated by the fuel cell;a fuel cell driving control device for controlling at least a supply of the reactive gases to the fuel cell; anda voltage variation rate obtaining device for obtaining a rate of variation in the voltage generated by the fuel cell when the load is varied,wherein the fuel cell driving control device is controlled based on the rate of variation in the generated voltage obtained by the voltage variation rate obtaining device.

2. The fuel cell system in accordance with claim 1, wherein the rate of variation in the generated voltage is obtained when the generated voltage increases.

3. The fuel cell system in accordance with claim 1, wherein the load is varied by applying momentarily a load to the fuel cell when the rate of variation in the generated voltage is obtained.

4. The fuel cell system in accordance with claim 1, further comprising: a temperature measuring device for measuring a temperature of the fuel cell,wherein the rate of variation in the generated voltage is obtained when the measured temperature of the fuel cell is equal to or less than 0° C.

5. The fuel cell system in accordance with claim 1, wherein the fuel cell driving control device performs control wherein the smaller the rate of variation in the generated voltage, the smaller the load applied to the fuel cell.

6. The fuel cell system in accordance with claim 1, wherein the fuel cell driving control device performs control wherein the greater the rate of variation in the generated voltage, the smaller an amount of the supplied reactive gases.

7. A method of activating a fuel cell which generates electric power using supplied reactive gases, the method comprising the steps of: measuring a rate of variation in a voltage generated by the fuel cell when a load applied to the fuel cell is varied immediately after the fuel cell is activated; anddriving the fuel cell wherein the smaller the obtained rate of variation in the generated voltage, the smaller the load applied to the fuel cell.

8. The method of activating a fuel cell in accordance with claim 7, wherein the load is varied by applying momentarily a load to the fuel cell when the rate of variation in the generated voltage is obtained.

9. The method of activating a fuel cell in accordance with claim 7, further comprising the step of: measuring a temperature of the fuel cell,wherein the rate of variation in the generated voltage is obtained when the measured temperature of the fuel cell is equal to or leas than 0C.

10. A method of activating a fuel cell which generates electric power using supplied reactive gases, the method comprising the steps of: measuring a rate of variation in a voltage generated by the fuel cell when a load applied to the fuel cell is varied immediately after the fuel cell is activated; anddriving the fuel cell wherein the greater the obtained rate of variation in the generated voltage, the smaller an amount of the reactive gases being supplied to the fuel cell.

11. The method of activating a fuel cell in accordance with claim 10, wherein the load is varied by applying momentarily a load to the fuel cell when the rate of variation in the generated voltage is obtained.

12. The method of activating a fuel cell in accordance with claim 10, further comprising the step of: measuring a temperature of the fuel cell,wherein the rate of variation in the generated voltage is obtained when the measured temperature of the fuel cell is equal to or leas than 0° C.