Apparatus for measuring current density of fuel cell
A fuel cell system includes a fuel cell. A current density measuring apparatus is provided on a cathode side of the fuel cell. The current density measuring apparatus includes a plurality of Hall elements provided at positions corresponding to measuring positions in an electrode surface. Each of the Hall element is attached to a ferrite core fitted to a pole of a sensor mounting plate. The ferrite core and the Hall element attached to the pole make up a current sensor.
1. A current density measuring apparatus for measuring current density in an electrode surface of a fuel cell, said fuel cell including an electrolyte electrode assembly and separators for sandwiching said electrolyte electrode assembly, said electrolyte electrode assembly including a pair of electrodes and an electrolyte interposed between said electrodes,
said current density measuring apparatus comprising:
a plurality of Hall elements provided at positions corresponding to measuring positions in said electrode surface; and
an output voltage measuring mechanism for measuring voltage values outputted from said Hall elements during power generation of said fuel cell,
wherein said Hall elements are provided on a single electrically conductive sensor mounting plate, and current density distribution in said electrode surface is determined based on said voltage values measured by said output voltage measuring mechanism.
2. A current density measuring apparatus according to claim 1 ,
wherein said sensor mounting plate has a plurality of poles provided at positions corresponding to said measuring positions in said electrode surface, and
wherein a current sensor is attached to each of said poles.
3. A current density measuring apparatus according to claim 2 , wherein said current sensor includes said Hall element and a substantially annular ferrite core having a slit; and
said ferrite core is externally fitted to said pole, and said Hall element is attached to said slit of said ferrite core.
4. A current density measuring apparatus according to claim 1 , wherein said sensor mounting plate is provided on a cathode side of said fuel cell.
5. A current density measuring apparatus according to claim 1 , wherein said output voltage measuring mechanism is connected to each of said Hall elements, and includes a current monitor for determining current density distribution in said electrode surface based on said voltage values outputted from said Hall elements.
6. A current density measuring apparatus according to claim 1 , wherein said sensor mounting plate is substantially the same size as said separators.
7. A current density measuring apparatus according to claim 1 , wherein said fuel cell further comprises end plates, and wherein said sensor mounting plate and said separators are positioned between said end plates.
8. A current density measuring apparatus according to claim 1 , further comprising a plurality of supporting columns, each supporting column positioned adjacent an associated one of said Hall elements on said sensor mounting plate.
9. A current density measuring apparatus according to claim 1 , wherein said separators comprise gas flow field grooves.