Patent ID: 7214250

Claim:
A method of making a lithium secondary cell comprising: providing an inner electrode body impregnated with a non-aqueous electrolyte, including a positive electrode and a negative electrode each comprising at least one metallic foil wound or laminated together; providing a positive electrode collector and a negative electrode collector to lead current out from the inner electrode body, each of said collectors having a protrusion portion that is (i) thicker than remaining parts thereof, (ii) has a lower surface and an opposed upper surface, and (iii) has a width that continuously increases from said lower surface to said upper surface; arranging predetermined parts of said metallic foil of said positive electrode and predetermined parts of said metallic foil of said negative electrode to contact said protrusion portion of said positive electrode collector and said protrusion portion of said negative electrode collector, respectively; irradiating said protrusion portion of said positive electrode collector and said protrusion portion of said negative electrode collector with energy beams; melting at least each said protrusion portion; and forming a weld joint between each said protrusion portion and said predetermined parts of said metallic foils.