US 7,442,455 B2Granted

Apparatus and method for protecting fuel cell

AssigneeHonda Giken Kogyo Kabushiki Kaisha

InventorsYasushi Kojima, Takashi Sasaki, Hiroshi Machida

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Abstract

A memory unit stores maps of predetermined determination threshold values for detection values detected by a hydrogen sensor according to an operating state of a fuel cell such as a difference in pressure between reaction gases at an anode and a cathode, supply pressure of the reaction gases, supply flow rate of the reaction gases and generated current of the fuel cell. A control unit obtains a predetermined determination threshold value from the memory unit based on the operating state of the fuel cell. Then, the detection value outputted from the hydrogen sensor and the determination threshold value obtained from the memory unit are compared, and in the event that the detection value is determined to exceed the determination threshold value, a predetermined protecting process is implemented for the fuel cell.

Claims6

Dependent claims

An apparatus for protecting a fuel cell which generates electricity by supplying as reaction gases hydrogen to an anode and oxygen to a cathode for electrochemical reaction, the apparatus comprising:

a hydrogen sensor for detecting hydrogen in off-gas discharged from the cathode;
an operating state detecting unit separate and distinct from the hydrogen sensor, wherein the operating state detecting unit includes a pressure detector for detecting the pressure of the reaction gases supplied to the anode and the cathode, a flow rate detector for detecting the flow rate of the reaction gases supplied to the anode and the cathode and a current controller for detecting a generated current of the fuel cell;
a memory unit for storing a determination threshold value which changes according to an operating state of the fuel cell during operation of the fuel cell, wherein the determination threshold value decreases when a loaded state of the fuel cell decreases;
a control unit coupled to the operating state detecting unit, the control unit configured to determine an abnormal state of the fuel cell by comparing a detection value outputted from the hydrogen sensor and the determination threshold value obtained from the memory unit according to the detected operating state of the fuel cell and determining that the fuel cell is in the abnormal state if the detection value exceeds the determination threshold value, wherein the control unit determines the operating state of the fuel cell based on a plurality of detections supplied to the control unit by the operating state detecting unit, the detections comprising a detection of the pressure of the reaction gases supplied to the anode and the cathode, a detection of the flow rate of the reaction gases supplied to the anode and the cathode and a detection of the generated current of the fuel cell;
and
a protecting unit for changing the operating state of the fuel cell if the control unit determines that the fuel cell is in the abnormal state.

3 more elements

A method for protecting a fuel cell which generates electricity by supplying as reaction gases hydrogen to an anode and oxygen to a cathode for electrochemical reaction, the method comprising:

detecting hydrogen in off-gas discharged from the cathode;
detecting a pressure of the reaction gases supplied to the anode and the cathode, a flow rate of the reaction gases supplied to the anode and the cathode, and a generated current of the fuel cell;
detecting an operating state of the fuel cell based on a detection of the pressure of the reaction gases supplied to the anode and the cathode, the flow rate of the reaction gases supplied to the anode and the cathode, or the generated current of the fuel cell;
obtaining a determination threshold value corresponding to the detected operating state of the fuel cell, wherein the determination threshold value decreases when a loaded state of the fuel cell decreases;
comparing a detection value of the hydrogen in the off-gas and the determination threshold value changing according to the detected operating state of the fuel cell during operation of the fuel cell;
determining that the fuel cell is in an abnormal state if the detection value exceeds the determination threshold value;
and
changing the operating state of the fuel cell if the fuel cell is determined to be in the abnormal state.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/623,011Filed 17 Jul 2003
Priority: JP 2002-20822517 Jul 2002
Published: US 2004/0018404 A129 Jan 2004
Granted: 28 Oct 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

H01M 8/04679
Failure or abnormal function: of fuel cell stacks
H01M 8/04228
During start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells: during shut-down
H01M 8/04388
Pressure; Ambient pressure; Flow: of anode reactants at the inlet or inside the fuel cell
H01M 8/04395
Pressure; Ambient pressure; Flow: of cathode reactants at the inlet or inside the fuel cell