Storage of fuel cell energy during startup and shutdown or other power transitions

A fuel cell power plant adapted to store energy which is removed from an associated fuel cell stack during transitions including transitions from being not operating to being operating, and vice versa, and power reduction transitions from a first level of power demanded by a load, to a second level of power demanded by said load, said second level being lower than said first level;

• comprising:
• a fuel cell stack;
• a controller interconnected with said fuel cell stack and responsive to one or more signals received by said controller to cause said fuel cell stack to start up, or to shut down, or to provide power to said load in response to demand for power by said load;
• an energy storage system associated with said fuel cell power plant, said energy storage system responsive to electrical output provided thereto to store corresponding energy;
• and
• storage control means, operable by said controller during transitions, selected from (a) startup of said fuel cell power plant, (b) shutdown of said fuel cell power plant, and (c) transition from providing power to said load at said first level to providing power to said load at said second level, to provide to said energy storage device at least a portion of the energy generated by said fuel cell stack in the form of electrical power output which is in excess of any power demanded by said load during any of said transitions, thereby limiting the maximum average voltage in the fuel cells of said fuel cell stack during any of said transitions.

A method of operating a fuel cell power plant adapted to store energy, which is removed from an associated fuel cell stack, in an energy storage system associated with said fuel cell power plant during transitions including transitions from being not operating to being operating, and vice versa, and power reduction transitions from a first level of power demanded by a load, to a second level of power demanded by said load, said second level being lower than said first level, said energy storage system responsive to electrical output provided thereto to store corresponding energy in response to a controller interconnected with said fuel cell stack and responsive to one or more signals received by said controller to cause said fuel cell stack to start up, or to shut down, or to provide power to said load in response to demand for power by said load, said method comprising:

• during transitions including (a) startup of said fuel cell power plant, (b) shutdown of said fuel cell power plant, and (c) transition from providing power to said load at said first level to providing power to said load at said second level, providing to said energy storage device at least a portion of the energy generated by said fuel cell stack in the form of electrical power output which is in excess of any power demanded by said load during any of said transitions, thereby limiting the maximum average voltage in the fuel cells of said fuel cell stack during any of said transitions.

A fuel cell power plant adapted to store energy, comprising:

• a fuel cell stack;
• a controller interconnected with said fuel cell stack, said controller responsive to at least one received signal, and said controller configured to control said fuel cell stack to provide power to a load;
• an energy storage system associated with said fuel cell power plant, said energy storage system responsive to power output provided thereto to store corresponding energy;
• and
• a storage control operable by said controller, said storage control configured to protect said fuel cell stack from adverse fuel cell operating conditions during operating transitions.

A fuel cell power plant adapted to store energy which is removed from an associated fuel cell stack comprising:

• a controller interconnected with said fuel cell stack and responsive to signals received by said controller to cause said fuel cell stack to start up and to cause said fuel cell stack to shut down;
• and
• an energy storage system associated with said fuel cell power plant, said energy storage system responsive to electrical output provided thereto to store corresponding energy;
• and
• storage control means operable by said controller, during a transition of operating conditions of said fuel cell stack, to extract in the form of electrical output, energy generated by said fuel cell stack, said electrical output being provided to said energy storage device, thereby limiting the maximum average voltage in the fuel cells of said fuel cell stack during said transition.

A fuel cell power plant adapted to store energy which is removed from an associated fuel cell stack during a power reduction transition from a first level of power demanded by a load, to a second level of power demanded by said load, said second level being lower than said first level;

• comprising:
• a fuel cell stack;
• a controller interconnected with said fuel cell stack and responsive to one or more signals received by said controller to cause said fuel cell stack to provide power to a load in response to demand for power by said load;
• an energy storage system associated with said fuel cell power plant, said energy storage system responsive to electrical output provided thereto to store corresponding energy;
• and
• storage control means, operable by said controller during a transition from providing power to said load at said first level to providing power to said load at said second level, to provide to said energy storage device at least a portion of the energy generated by said fuel cell stack in the form of electrical power output which is in excess of the power demanded by said load, thereby limiting the maximum average voltage in the fuel cells of said fuel cell stack during said transition.