FUEL CELL HYDROGEN CONCENTRATION ESTIMATION DEVICE AND FUEL CELL SYSTEM

摘要

The invention provides an apparatus for estimating fuel-cell hydrogen concentration and a fuel cell system which exploit the correlation between impedance semicircles and hydrogen concentrations to estimate fuel-cell hydrogen concentration. A fuel cell system includes a fuel cell 2, an impedance measuring instrument 3, and a control device 5. The control device 5 is connected to the impedance measuring instrument 3. The impedance measuring instrument 3 measures the impedance of the fuel cell 2 according to the AC impedance method. The control device 5 stores in advance a reference value corresponding to a reference hydrogen concentration. The control device 5 compares the real part Z' of impedance acquired via the impedance measuring instrument 3 against the reference value. When Z' is equal to or greater than the reference value, the control device 5 estimates the hydrogen concentration of the fuel cell 2 to be equal to or less than the reference hydrogen concentration.