A metal current collector substrate adapted to be inserted into an elongated cylindrical housing of a primary electrochemical cell. The metal current collector substrate is employed together with porous carbon and fiberglass separator elements to form a carbon current collector electrode/separator assembly for use in the electrochemical cell.The metal current collector substrate in accordance with the invention comprises a thin, circular, metal disc (e.g., of nickel) having a plurality of curved notches around its periphery. The notches are equally-spaced about the periphery of the disc (e.g., at 45.degree. intervals) and define a plurality of deflective, resilient arcuate portions intermediate to the notches. Prior to insertion into the housing of the cell, the disc is flat and has a diameter greater than the internal diameter of the housing. The disc is inserted into the housing by pushing the disc longitudinally into the housing whereupon the arcuate portions are deflected upwardly by physical contact with the interior wall of the housing. This deflection causes the arcuate portions to move toward each other and in turn to cause the disc to generally conform to the interior cross section of the housing. The arcuate portions following the deflection thereof are at acute angles with respect to the interior wall of the housing and make direct physical contact with the wall of the housing. In addition, due to the adjacency of the notches in the disc to the wall of the housing, a plurality of passageways are established between the disc and the interior wall of the housing.