a central current path 23 that is indicated by arrows fig9 and 10 diagrammatically illustrate that it is not compulsory according to the invention to allow the connection region 6 to terminate exactly at the connecting end 15 of the connecting pin 12 it is quite possible for example due to reasons relating to manufacturing technology for the stack 5 to contact a piece prior to its end but the construction can still manage without half shells or similar current distribution structures the reason for this is that the most critical region of the stack 5 in the proximity of the connecting pin 12 where relatively high electrical current densities can occur during operation is efficiently cooled by the solid connecting pin 12 itself and by the u201c protruding u201d part of the stack 5 and it therefore operates with only low current densities it is also advantageous in these embodiments for an efficient electrically conductive uppermost sheet metal layer 3 to have a greater thickness t where appropriate it is also necessary for at least one further sheet metal layer 1 2 to be connected to the connecting end 15 of the connecting pin 12 in an efficient electrically conductive manner in order not to generate any high current densities in the uppermost sheet metal layer 3 this can be achieved by way of example by using a welded connection or a suitable brazed connection including two or multiple sheet metal layers it is also possible to provide an intermediate piece 9 between the connecting pin 12 and the stack 5 for the purpose of increasing the contact area on 200 to 300 of the cross section area of the connecting pin 12 depending upon the length of.