Welding gun and welding method

A welding method using a welding gun, the welding gun comprising

• a first arm,
• a second arm movable with respect to the first arm along a first axis and a second axis orthogonal to the first axis,
• a first welding electrode disposed on the first arm, the first welding electrode including a first roller rotatable around a first rotational axis with respect to the first arm, the first roller including a first cylindrical surface with the first rotational axis as a central axis and a first side surface orthogonal to the first rotational axis,
• a second welding electrode disposed on the second arm, the second welding electrode including a second roller rotatable around a second rotational axis with respect to the second arm, the second roller including a second cylindrical surface with the second rotational axis as a central axis and a second side surface orthogonal to the second rotational axis, wherein
• the first arm supports the first welding electrode such that the first rotational axis is substantially parallel to a plane including the first and second axes, and the first side surface faces toward a first direction along the first axis,
• the second arm supports the second welding electrode such that the second rotational axis is substantially parallel to the plane including the first and second axes, and the second side surface faces toward a second direction opposite to the first direction along the first axis, and
• a slide mechanism disposed on at least one of the first arm or the second arm, the welding method comprising:
• enabling the first welding electrode to slide to below the second welding electrode by the slide mechanism, so as to enable a selection of
• a first mode in which the first cylindrical surface of the first welding electrode and the second cylindrical surface of the second welding electrode are brought into contact with one side of a workpiece to weld the workpiece,
• a second mode in which the workpiece is sandwiched, to perform welding of the workpiece, between the first cylindrical surface of the first welding electrode and the second cylindrical surface of the second welding electrode, and
• a third mode in which the workpiece is sandwiched, to perform welding of the workpiece, between the first side surface of the first welding electrode rotatable around the first rotational axis and the second side surface of the second welding electrode rotatable around the second rotational axis.