We've been working on this, actually, as an alternative energy source, starting way back with Johnson &amp; Johnson, to run an iBOT, because the best batteries you could get -- 10 watt-hours per kilogram in lead, 20 watt-hours per kilogram nickel-cadmium, 40 watt-hours per kilogram in nickel-metal hydride, 60 watt-hours per kilogram in lithium, 8,750 watt-hours of energy in every kilogram of propane or gasoline -- which is why nobody drives electric cars.
事实上我们正在研究这种 替代能源 从强生公司开始，到使用iBOT, 因为你能得到的最好电池是 每公斤铅十瓦特小时 每公斤镍镉二十瓦特小时 每公斤镍金属水合物四十瓦特小时 每公斤锂六十瓦特小时 每公斤丙烷或汽油八千七百五十瓦特小时 因此根本没人会开电动车