Composite collector bar

An electrolytic cell in a series of electrolytic cells for the production of aluminum comprising:

• a shell and a refractory arrangement forming a working cavity for containment of high temperature liquids;
• an electrically-conducting cathode comprising a plurality of cathode blocks forming a base of the working cavity;
• an electrical current busbar system located externally of the shell;
• and
• at least one anode suspended within the electrolytic cell and in contact with the high temperature liquids in the working cavity;
• at least one collector bar received within a recess in at least one cathode block of the cathode, the at least one collector bar being positioned in the cathode block to not directly contact the liquids in the working cavity, the collector bar comprising a first conductor which electrically connects to the busbar system, the first conductor having an external surface or surfaces which electrically contacts the cathode block and at least one second conductor having a lower electrical resistance to the first conductor, wherein the second conductor is mechanically or chemically bonded to the external surface of the first conductor or into a recess formed in an external surface of the conductor to establish and maintain electrical connectivity with the first conductor, wherein the mechanically or chemically bonded second conductor forms at least one part of an one external surface of the first conductor;
• and
• the electrical current busbar system transfers electrical current from the at least one collector bar of the electrolytic cell to the at least one anode of a next electrolytic cell in the series of electrolytic cells.