Fuel cell with triangular buffers
An oxygen-containing gas flow field for supplying an oxygen-containing gas from an oxygen-containing gas supply passage to an oxygen-containing gas discharge passage is formed on a first metal plate. The oxygen-containing gas flow field includes oxygen-containing gas flow grooves as serpentine flow grooves having two turn regions T 1 , T 2 . The oxygen-containing gas flow grooves have substantially the same length. The oxygen-containing gas flow grooves are connected to an inlet buffer and an outlet buffer at opposite ends. The inlet buffer and the outlet buffer have a substantially triangular shape, and are substantially symmetrical with each other.
1. A fuel cell formed by stacking an electrolyte electrode assembly and separators alternately, said electrolyte electrode assembly including a pair of electrodes and an electrolyte interposed between said electrodes,
wherein a reactant gas supply passage and a reactant gas discharge passage extend through said fuel cell in a stacking direction of said fuel cell;
a reactant gas flow field is formed for supplying a reactant gas along an electrode surface;
said reactant gas flow field includes a plurality of serpentine flow grooves having substantially the same length, said serpentine flow grooves including an even number of turn regions formed on a surface of said separator;
a substantially triangular inlet buffer for connecting said serpentine flow grooves and said reactant gas supply passage;
a substantially triangular outlet buffer for connecting said serpentine flow grooves and said reactant gas discharge passage; wherein
the reactant gas supply passage and the reactant gas discharge passage are positioned on extensions of the respective terminal portions of the serpentine flow grooves,
each of the inlet buffer and the outlet buffer has a first side that forms an interface with terminal portions of the serpentine flow grooves, the first side of each of said inlet buffer and said outlet buffer is substantially perpendicular to the terminal portions of said serpentine flow grooves;
each of the inlet buffer and the outlet buffer has a second side that is substantially parallel to the terminal portions of said serpentine flow grooves;
each of the inlet buffer and the outlet buffer has a third side that is oblique to the first and second sides of each of the inlet buffer and the outlet buffer, the third oblique side of each of the inlet buffer and the outlet buffer is substantially parallel to one side of each of the reactant gas supply passage and the reactant gas discharge passage; and
said inlet buffer and said outlet buffer are formed substantially symmetrically with each other.
2. A fuel cell according to claim 1 , wherein a plurality of bosses are formed in at least one of said inlet buffer and said outlet buffer.
3. A fuel cell according to claim 1 , wherein each of said reactant gas supply passage and said reactant gas discharge passage has at least one oblique side; and
said oblique side of said reactant gas supply passage faces the oblique side of said inlet buffer, and said oblique side of said reactant gas discharge passage faces the oblique side of said outlet buffer.
4. A fuel cell according to claim 1 , wherein said fuel cell includes a coolant supply passage and a coolant discharge passage, said reactant gas supply passage includes a fuel gas supply passage and an oxygen-containing gas supply passage, and said reactant gas discharge passage includes a fuel gas discharge passage and an oxygen-containing gas discharge passage; and
among six passages comprising said fuel gas supply passage, said oxygen-containing gas supply passage, said coolant supply passage, said fuel gas discharge passage, said oxygen-containing gas discharge passage, and the coolant discharge passage, three passages extend through a left end of said separator, and the other three passages extend through a right end of said separator.