How It's Made Season 1 Episode 13 Bicycle Helmets, Aluminum, Automotive Brakes, Lithium-Ion Batteries ( Air Date 2001-03-31 ) Genre Documentary category. Overview "Expanded foam and protective shells are combined into bicycle helmets, aluminum is extracted and processed into usable metal, friction components and hydraulic parts become automotive braking systems, and precisely layered materials are assembled into rechargeable lithium-ion batteries.".