Liquid cooling seal box, box cover thereof, and in-vehicle cooling system

The present disclosure provides a liquid cooling seal box, a box cover thereof, and an in-vehicle cooling system. The liquid cooling seal box includes a sealed heat conduction box body, an inner cavity of the heat conduction box body includes a heating device and an insulating liquid in which the heating device is immersed, the insulating liquid absorbs heat of the heating device and vaporizes, vaporized steam rises to the top of the inner cavity of the heat conduction box body to be cooled and liquefied, and a liquefied insulating liquid falls back into the insulating liquid at the bottom of the inner cavity. The liquid cooling seal box of the present disclosure resolves problems of reliability, harsh environment, balance of volume and computation power, etc., is suitable for an in-vehicle system, and may implement stable and reliable running of a server in an in-vehicle environment.