The invention discloses a cooling
system of a
flywheel energy storage device. The
flywheel energy storage device consists of a shell and an internal disc-type motor, wherein the shell has a vacuum sealing structure; an upper oil cavity and a lower oil cavity are respectively arranged at the upper part and lower part of the shell; the shell internally comprises at least one set of
flywheel; a center shaft of each flywheel is a hollow mandrel, and an axle hole is formed in the center of the center shaft and is communicated with the upper oil cavity and the lower oil cavity; an
oil tank is arranged outside the shell; the
oil tank is communicated with the upper oil cavity by an upper oil
pipe and is communicated with the lower oil cavity by an oil return
pipe; the oil return
pipe is provided with a third valve, an
oil pump and a radiator. The cooling
system can be used for cooling a rotor by the axle hole, so that a great deal of heat of the rotor which rotates at a high speed can be taken away in time, and safe and stable operation of the
flywheel energy storage device is guaranteed. An upper bearing, a lower bearing and a
stator disc are cooled in time by part of cooling oil, and the bearings can be lubricated, so that the reliable work of key parts can be guaranteed, and the defects of
cavitation and the like of a pump caused by low pressure can be avoided.