Lift car with liftable car roof

The lift car comprises a lift car top device, a lift car assembly, stand columns, a safety tongs frame, a lift car bottom, guide shoes and a lift car door system, and the lift car top device comprises a lift car top frame, a supporting mechanism, a power device, a guide mechanism, a working platform and a tension element; the working platform is connected with the car roof frame through a supporting mechanism, the working platform is connected with the power device through a tension element, and the working platform can descend into the car under the action of the power device; the car roof frame is provided with an upper frame and a lower frame, and the upper frame and the lower frame are fixedly connected through a connecting piece; the power device is fixed between the upper frame and the lower frame, the tension elements are connected to the four corners of the working platform through the guide mechanism and transmit power synchronously, and the guide mechanism is fixed to the upper frame. The power devi