Abstract: The present invention discloses a variable voltage battery pack including a bottom cover, a housing, a sampling circuit board, a variable voltage assembly, a spring, a push rod and a ventilation plate; removing the ventilation plate may increase heat dissipation effect inside the housing, and to remove the ventilation plate, a rotating handle is rotated to cause a gear shaft to drive a square column to move so as to remove the square column from an insertion hole in an upper cover, thus removing the ventilation plate and increasing the internal heat dissipation effect, which helps to maintain a normal operating temperature of the battery pack and improve battery performance and life.