Liquid-cooling device and system thereof

A liquid-cooling device comprising:

• a liquid reservoir case having a heat exchange chamber, an inlet and an outlet, the inlet and the outlet being in communication with the heat exchange chamber, the heat exchange chamber being for a cooling liquid to pass through;
• a pump component for circulating the cooling liquid, the pump component including a stator, a rotor and an impeller connected with the rotor, the rotor and the impeller being disposed in the heat exchange chamber in a position spaced from a central region of the heat exchange chamber, the impeller being positioned in adjacency to the inlet and exposed to the cooling liquid in the heat exchange chamber;
• and
• a heat exchange component connected with the liquid reservoir case as a bottom side of the heat exchange chamber, the heat exchange component having a heat contact face and a heat exchange face in contact with the cooling liquid in the heat exchange chamber, the heat exchange face being defined with a water incoming section corresponding to the impeller, multiple radiating fins being disposed on the rest section of the heat exchange face, wherein the radiating fins are radially arranged at intervals, each radiating fin having a first end directed to the impeller and a second end radially extending away from the water incoming section, a first spacing formed between the first end of each radiating fin, and a second spacing formed between the second end of each radiating fin, the first spacing narrower than the second spacing.