Plate welding auxiliary mechanism and welding mechanism

The invention provides a plate welding auxiliary mechanism, which utilizes multifunctional floating to realize long-distance high-precision welding of two laminated welding plates. The plate welding auxiliary mechanism comprises a base, a lifting mechanism and a support, wherein the lifting mechanism is fixedly arranged on the base and used for driving the support to move up and down so as to tightly top or loose the plates; an adjusting unit is arranged at the lower end of the support and comprises a first floating unit and a second floating unit, wherein the bottom of the first floating unitis higher than the bottom of the second floating unit, and the second floating unit automatically floats after abutting against the plates until the first floating unit abuts against the plates so asto reach a predetermined pre-tightening force, so that the support automatically floats along with the surface of the two pressed plates, and thus the pressing of the two plates is completed. According to the plate welding au