Circuit connection control system of fuel cell and method of operating the same

A fuel cell, comprising:

• a plurality of unit cells;
• and
• a circuit connection control system,
• wherein the circuit connection control system includes:
• a point connection portion to which an anode current collecting portion and a cathode current collecting portion of each unit cell are electrically connected;
• a voltage measuring unit that measures an output voltage of each unit cell;
• a switching unit connecting the anode current collecting portions and the cathode current collecting portions of the plurality of cells at the point connection portion;
• and
• a DC-DC converter that converts a voltage generated from the fuel cell to a predetermined voltage, and
• wherein the switching unit includes:
• a plurality of main switches, one main switch being installed at an inlet end of each unit cell, the main switches being equal in number to the unit cells;
• a plurality of series connecting switches, each series connecting switch connecting an outlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each series connecting switch and the inlet end of the another unit cell, the series connecting switches being one less in number than the unit cells;
• a plurality of by-pass switches that each connect an inlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each by-pass switch and the inlet end of the another unit cell, the by-pass switches being equal in number to the unit cells;
• and
• a plurality of parallel connecting switches that each connect an outlet end of one unit cell of the plurality of unit cells and an outlet end of another unit cell of the plurality of unit cells, the parallel switches being one less in number than the unit cells.

A method of operating a circuit connection control system of a fuel cell having a plurality of unit cells, the method comprising:

• measuring an output voltage of each unit cell;
• and
• if a first unit cell showing an output voltage lower than a predetermined first voltage is detected in the measuring, connecting the first unit cell in parallel to a second unit cell, wherein the circuit connection control system includes:
• a point connection portion to which an anode current collecting portion and a cathode current collecting portion of each unit cell are electrically connected;
• a voltage measuring unit that measures an output voltage of each unit cell;
• a switching unit connecting the anode current collecting portions and the cathode current collecting portions of the plurality of unit cells at the point connection portion;
• and
• a DC-DC converter that converts a voltage generated from the fuel cell to a predetermined voltage, and
• the switching unit includes:
• a plurality of main switches, one main switch being installed at an inlet end of each unit cell, the main switches being equal in number to the unit cells;
• a plurality of series connecting switches, each series connecting switch connecting an outlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each series connecting switch and the inlet end of the another unit cell, the series connecting switches being one less in number than the unit cells;
• a plurality of by-pass switches that each connect an inlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each by-pass switch and the inlet end of the another unit cell, the by-pass switches being equal in number to the unit cells;
• and
• a plurality of parallel connecting switches that each connect an outlet end of one unit cell of the plurality of unit cells and an outlet end of another unit cell of the plurality of unit cells, the parallel switches being one less in number than the unit cells.

A method of operating a circuit connection control system of a fuel cell having a plurality of unit cells, the method comprising:

• measuring an output voltage of each unit cell;
• if a first unit cell showing an output voltage lower than a predetermined first voltage is detected in the measuring, determining whether the output voltage of the first unit cell is lower than a predetermined second voltage, the second voltage being lower than the first voltage;
• connecting the first unit cell in parallel to a second unit cell if the output voltage of the first unit cell is equal to or greater than the second voltage;
• and
• electrically separating the first unit cell from other unit cells if the output voltage of the first unit cell is lower than the second voltage,
• wherein the circuit connection control system includes:
• a point connection portion to which an anode current collecting portion and a cathode current collecting portion of each unit cell are electrically connected;
• a voltage measuring unit that measures an output voltage of each unit cell;
• a switching unit connecting the anode current collecting portions and the cathode current collecting portions of the plurality of unit cells at the point connection portion;
• and
• a DC-DC converter that converts a voltage generated from the fuel cell to a predetermined voltage, and
• the switching unit includes:
• a plurality of main switches, one main switch being installed at an inlet end of each unit cell, the main switches being equal in number to the unit cells;
• a plurality of series connecting switches, each series connecting switch connecting an outlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each series connecting switch and the inlet end of the another unit cell, the series connecting switches being one less in number than the unit cells;
• a plurality of by-pass switches that each connect an inlet end of one unit cell of the plurality of unit cells and an inlet end of another unit cell of the plurality of unit cells, one of the main switches being between each by-pass switch and the inlet end of the another unit cell, the by-pass switches being equal in number to the unit cells;
• and
• a plurality of parallel connecting switches that each connect an outlet end of one unit cell of the plurality of unit cells and an outlet end of another unit cell of the plurality of unit cells, the parallel switches being one less in number than the unit cells.