The fluid reservoir of an embodiment according to the present invention includes: first outer wall section, which forms a front in length direction, width direction and short transverse, is stored in space segment therein to form a fluid;Multiple partitions are arranged along the length direction of the first outer wall section the space segment is divided into multiple sub-space portions;And end sections, between the outmost partition and the first outer wall section in multiple partitions, wherein each partition is formed with a fluid passage holes, which includes: the gas passage orifices being located at the top of partition;And the liquid passage holes positioned at partition bottom, so that the fluid between sub-space portion is interconnected.