The majority of Lithium-Ion batteries are spot welded rather than soldered (soldering injects a lot of heat), which makes recycling battery packs a rather time consuming and annoying job. The best is probably to grind them up and then to create a sludge and do a sort by centrifuge or some other bulk method of processing the materials.

A typical Lithium-Ion cell contains Aluminum, steel, possibly a protection circuit (fibreglass, electronics components), carbon, copper, an electrolyte with lithium in solution and quite probably other elements besides.