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US 6,953,630 B2Granted
Fuel cell anomaly detection method and apparatus
AssigneeBallard Power Systems Inc.
InventorBrian Wells
Life of this patent
Estimating the term…
Abstract
A respective bipolar junction transistor is coupled across pairs of fuel cells in a fuel cell stack to monitor the voltage across each fuel cell pairs for a drop in voltage below a threshold voltage. A respective optoisolator coupled to each of the transistors produces a digital signal corresponding to the status of the respective pair of fuel cells. An “AND” circuit produces a single digital signal corresponding to the status of one or more pairs of fuel cells.
Claims32
A fuel cell system, comprising:
- a fuel cell structure comprising at least one fuel cell;
- at least one pnp bipolar junction transistor having a base, an emitter and a collector, the transistor coupled to respond to a voltage across the fuel cell structure;
- an alarm circuit coupled to the collector of the transistor;
- and
- an optoisolator having a first terminal, a second terminal and a switching terminal, the first terminal of the optoisolator coupled to a ground, the second terminal coupled to a positive reference voltage source that is positive with respect to the ground, the switching terminal of the optoisolator coupled between the collector of the transistor and a negative reference voltage source that has a voltage that is less than a lowest voltage of the fuel cell structure.
2 more elements
A fuel cell system, comprising:
- a pair of solid polymer fuel cells electrically connected to one another in series;
- at least one pnp bipolar junction transistor having a base, an emitter and a collector, the transistor coupled to respond to a voltage across only the pair of solid polymer fuel cells;
- and
- an alarm circuit coupled to the collector of the transistor.
1 more element
A fuel cell system, comprising:
- a fuel cell stack comprising at least two fuel cell structures, each fuel cell structure comprising a pair of fuel cells;
- for each fuel cell structure, a respective pnp bipolar junction transistor, comprising a base, an emitter and a collector, and coupled to respond to a voltage across the fuel cell structure, and
- for each fuel cell structure, a fuel cell pair optoisolator having an output including a first terminal, a second terminal, and an input including a switching terminal, the first terminal coupled to a ground, the second terminal coupled to a positive reference voltage that is positive with respect to the ground, and the switching terminal coupled between the collector of the transistor and a negative reference voltage that has a voltage less than a lowest voltage of the respective fuel cell structure.
A monitoring system for monitoring fuel cells, comprising:
- a transistor having a first terminal, a second terminal, and a switching terminal, the first terminal and the switching terminal of the transistor couplable to respond to a voltage across at least two fuel cells;
- and
- an optoisolator having a first terminal, a second terminal and a switching terminal, the first terminal of the optoisolator coupled to a ground reference voltage, the switching terminal coupled between the second terminal of the transistor and a first reference voltage below the ground reference voltage for control by the transistor in response to the voltage across the fuel cells, the second terminal of the optoisolator coupled to a second reference voltage above the ground reference voltage to produce a digital signal on the second terminal corresponding to an operational status of the fuel cells.
A monitoring system for monitoring fuel cells, comprising:
- a set of digitizing switches, each of the digitizing switches having a first terminal coupled to a ground, a second terminal coupled to a positive reference voltage with respect to the ground, and a switching terminal coupled to a negative reference voltage with respect to ground, each of the digitizing switches responsive to a first defined potential difference between the first terminal and the switching terminal of the respective digitizing switch;
- and
- a set of triggering switches, each of the triggering switches having a first terminal and a switching terminal couplable across a respective one of a number of fuel cell structures, and a second terminal coupled to the switching terminal of a respective one of the digitizing switches, each of the triggering switches responsive to a second defined potential difference between the first terminal and the switching terminal of the triggering switch.
A method of monitoring fuel cells in a fuel cell structure, comprising:
- coupling a first terminal and a switching terminal of a transistor across a pair of fuel cells electrically connected in series forming a fuel cell structure;
- producing a first indication when the voltage across the fuel cell structure is greater than a predetermined threshold voltage;
- and
- producing a second indication, different from the first indication, when the voltage across the fuel cell structure is not greater than the threshold voltage.
1 more element
A method of monitoring fuel cells in a fuel cell structure, comprising:
- coupling a first terminal and a switching terminal of a transistor across a pair of fuel cells electrically connected in series forming a fuel cell structure;
- producing a first indication when the voltage across the fuel cell structure is greater than a threshold voltage;
- producing a second indication, different from the first indication, when the voltage across the fuel cell structure is not greater than the threshold voltage;
- coupling a second terminal of the transistor to an optoisolator;
- and
- activating the optoisolator when current is passing between the first and the second terminals of the transistor and deactivating the optoisolator when current is not passing between the first and the second terminals of the transistor.
3 more elements
A method of monitoring fuel cells in a fuel cell stack, comprising:
- monitoring a voltage across a first set of at least two fuel cells in the fuel cell stack with at least a first transistor electrically coupled across the first set of at least two fuel cells;
- simultaneously monitoring a voltage across a second set of at least two fuel cells in the fuel cell stack with at least a second transistor electrically coupled across the second set of at least two fuel cells;
- producing a first indication when the voltage across each of the first and the second sets of at least two fuel cells in the fuel cell stack is greater than a threshold voltage;
- and
- producing a second indication when the voltage across any of the first and the second sets of at least two fuel cells in the fuel cell stack is not greater than the threshold voltage.
2 more elements
A method of monitoring fuel cells in a fuel cell stack, comprising:
- monitoring a voltage across a first set of at least two fuel cells in the fuel cell stack with at least a first transistor and a first optoisolator;
- simultaneously monitoring a voltage across a second set of at least two fuel cells in the fuel cell stack with at least a second transistor and a second optoisolator;
- producing a first indication when the voltage across each of the first and the second sets of at least two fuel cells in the fuel cell stack is greater than a threshold voltage;
- and
- producing a second indication when the voltage across any of the first and the second sets of at least two fuel cells in the fuel cell stack is not greater than the threshold voltage.
2 more elements
Dependencies are inferred from the claim text.