Transporting batteries can possibly cause fires if the battery terminals inadvertently come in contact with conductive materials such as keys, coins, hand tools and the like. The U.S. Department of Transportation Hazardous Material Regulations (HMR) actually prohibits transporting batteries in commerce or on airplanes (i.e. packed in suitcases and carry-on luggage) UNLESS they are properly protected from short circuits. So anytime you transport individual batteries, make sure that the battery terminals are protected and well insulated from materials that could contact them and cause a short circuit.