Abstract: Welding electrode arrangement and method for welding one interconnector of two adjacent electrochemical cells of a rechargeable battery. The two electrochemical cells are disposed to be separated by means of a housing partition. The interconnectors are disposed to face one another on two opposite sides of the housing partition. An opening is disposed in a region of the housing partition. The method comprises contacting the interconnectors with a welding electrode arrangement. The welding electrode arrangement has at least one pair of welding electrodes. One welding electrode of the at least one pair of welding electrodes contacts in each case one of the interconnectors by means of an insert part. The method further comprises welding the interconnectors in such a manner that the material of the interconnectors melts at least in regions and is connected in a materially bonded manner through the opening in the housing partition.