| 摘要 |
PURPOSE:To control the I-V property of a fuel cell, raise the discharge current of the cell stepwise in proportion to the temperature rise of the fuel cell, and shorten the time required for starting the cell without loss of a unit cell by finding the rate of voltage lowering i.e., dV/dI and d<2>V/dI<2> values in sequence according to the discharge current and discharge voltage of the fuel cell which are detected when the cell is started. CONSTITUTION:The output circuit of a fuel cell stack 6 is provided with a current detector 7 and a voltage detector 8 and thus the discharge current I and discharge voltage V of the fuel cell are detected when needed, and a change in the I-V value between two close points of time is calculated by an arithmetic and control portion 9. The values of dV/dI and d<2>V/dI<2> i.e., the rate of lowering of the output voltage to the rate of increase of the discharge current of the fuel cell detected when the cell is started, are calculated when needed, and, when the d<2>V/dI<2> is less than 0 and also the dV/dI value is dropped to a predetermined level, the discharge current is maintained at a fixed value to heat the fuel cell. When the discharge voltage V is raised to a predetermined value the discharge current I is increased and a series of control for maintaining the discharge current constant in a predetermined level approximating the dV/dI value is repeated so that the fuel cell is heated to its working temperature. |
