An improved electrochemical cell and method of fabricating same

An electrochemical cell having a cell package made of a metallic material to allow the cell package to be sealed by welding, even when contaminated, and a method of manufacturing the electrochemical cell. The method of fabricating the cell, includes the steps of forming an electrode cell stack and a metallic cell package having a base portion and a lid portion which arc welded to each other to define an enclosure, the cell package including a first section for receiving the cell stack and a second section having an inlet port which communicates with the first section; placing the cell stack into the enclosure in the first section; sealing the lid portion to the base portion around a periphery of the cell package to form a peripheral seam (18); applying a vacuum to the enclosure through the inlet port in the cell package; introducing an electrolyte into the enclosure via the inlet port; and welding the lid portion to the base portion to form a first weld seam (62) located between the first and second sections to seal off the first section from the second section. The first weld scam (62) extends from the peripheral seam on a first side of the cell package to the peripheral seam a second side of the cell package. The method further includes the steps of puncturing the cell package to form an evacuation port located in a third section of the cell; partially charging the cell stack resulting in generation of gases inside the enclosure; applying a vacuum to the evacuation port of the cell stack to withdraw the gases; and sealing the lid portion to the base portion across a second weld seam located between the first section and the third section.