As shown in FIGS. 13 to 16, a liquid cooling system of the present embodiment includes a heat exchanger radiator 1, a cooling block 6, a shrinking device, and a water pump (not shown). Preferably, the shrinking device is disposed within the cooling block 6 between an upper cooling block housing 61 and a lower cooling block housing 62. A housing 2 of the shrinking device is in fluid communication with the water pump, and a shrinking bag 4 is in communicated with the outside of the housing 2 (i.e., with the outside atmosphere) through a vent hole 51. The housing 2 includes a connection portion 9 in fluid communication with the interior of the water pump. One end of the shrinking bag 4 is an open end arranged with a sealing nut 5, and the sealing nut 5 is in threaded connection with the outside of the housing 2, and the vent hole 51 is arranged on the end face of the sealing nut 5. When the internal pressure of the system increases, the volume of the area communicated with the internal waterway increases, and correspondingly the part communicated with the external atmosphere is reduced. The pressure difference between the inside and the outside of the system can be balanced via the change in the volume of the shrinking bag 4.

In summary, according to various embodiments of the present invention, when the internal pressure of the system is excessive, the internal volume is expanded by squeezing the shrinking bag, so that the increased pressure is released and the problem of liquid leakage caused by high-pressure is fundamentally solved.