Development of prismatic lithium-ion cells using aluminum alloy casing

Light weight prismatic lithium-ion cells for cellular phones have been developed using an aluminum alloy case. Various kinds of aluminum alloys have been examined from the view point of the electrochemical stability, mechanical strength, the ability to be laser-welded and easy formation into a casing. An aluminum alloy with 1.1 wt.% Mn was the best candidate for the casing. The energy density of the lithium-ion cell with the aluminum alloy casing was improved by about 30% compared to the conventional steel casing.