Electric drag racers are test-driving the technology that will eventually spill over into mass production cars, analysts say. Today’s hybrid cars, like Toyota Motor Corp.’s Prius, use nickel metal hydride batteries, which cost less than lithium-ion batteries. But the price of lithium-ion is expected to drop. In addition, the latest generation of batteries offers a higher rate of conductivity and takes less time to charge — the KillaCycle’s battery pack can be juiced up in five minutes. New materials also mean the battery is less prone to overheating and explosions — a danger of earlier generations.