Abstract: Disclosed are a composite heating system, and a heating method and heating apparatus thereof. Two heaters are provided in a heating apparatus of a liquid heating system of the composite heating system. The two heaters are connected to an external power source interface module and a battery pack output power source interface module by a relay group. In the disclosure, by controlling relays in the relay group, during charging preheating, the first heater and the second heater are able to be powered by an external power source and be self-powered by batteries in a battery pack, respectively. When the two heaters are self-powered by batteries in the battery pack, a pulse discharge manner is used, thereby increasing a heating efficiency of the liquid heating system in a low-temperature environment, and increasing a temperature increasing speed of batteries.

Abstract: A cell and an assembly method thereof. The cell has an elongated structure with a positive electrode end and a negative electrode end. The negative electrode end is provided with a liquid injection hole, a tab protector and a single-cell collection board. A negative electrode column is connected to a negative tab on a cell core set through an aluminum plate, which is bendable to be accommodated into an accommodating cavity. The liquid injection hole is sunk into an avoidance hole on a top frame plate of the tab protector to clamp the tab protector. The electrolyte flows through the accommodating cavity to fill a core cavity, and the liquid injection hole is sealed by a sealing mechanism including a steel ball welded in thxoer liquid injection hole and a structural adhesive filled in the recess.