Patent ID: 8481223

Claim:
A fuel cell stack, comprising: a plurality of electricity generating units configured for electrochemically reacting fuel and oxidizing gas to generate electrical energy; and a fastening member securing the plurality of electricity generating units, wherein at least one of the plurality of electricity generating units comprises a membrane electrode assembly (MEA) and separators disposed on each side of the MEA, wherein each separator is rectangular, wherein each separator comprises a channel on a surface facing the MEA, wherein at least one channel is divided into a multiple of 2 sub-channels that is greater than 2, wherein the sub-channels have substantially the same fluid passage length, wherein the channel is further divided into an inlet part, a branching part and an outlet part, wherein the sub-channels are mirror images of each other with respect to a first axis passing through a center of a first side of each separator in the branching part, wherein each separator comprises a plurality of fastening holes through which the fastening member penetrates accumulated surfaces of the fuel cell stack, wherein the number of sub-channels is a multiple of 2 of number of fastening holes, and wherein the plurality of fastening holes is disposed on the first axis passing through a center of a first side of each rectangular separator.