Electrified vehicles are fairly new in the scheme of automotive development. Sure, there have been a few specialty vehicles in decades before now, but they were never meant for, or ever reached, production stage. The reason for this is, of course, the limitations of battery technology. Consider the ubiquitous lead-acid battery that is in nearly every vehicle on the road today. Lead-acid battery technology has been around, like the automobile, for over one hundred years, and is one of the most reliable today.
The lead-acid rechargeable battery that is found in a gasoline-powered vehicle, for instance, is basically used only to start the vehicle and to allow for fluctuations in supply and demand in the electrical system. In an electric vehicle, though, the battery is used for everything, and the only way to make up for the power generated by an engine is to multiply the number of batteries running the vehicle.
If automakers, such as Tesla Motors, wanted to build the Model S electric vehicle using lead-acid battery technology, it might work, but it would weigh two or three times more and have half the range. The problem with lead-acid batteries is they are heavy for their power capacity. For example, the lithium-ion [Li-ion] battery pack in the Tesla Model S is rated at 85kWh weighing about 800 pounds. The same 85kWh in lead-acid batteries could easily top 2,500 pounds, pushing the Tesla Model S curb weight to over 7,000 pounds!
“The type of vehicle we can create is fundamentally different every time that [battery] tech moves a little forward,” said Tesla Motors co-founder JB Straubel. [italics mine] Battery technology is moving forward about 5% to 8% every year, which amounts to reduced weight, better charging and discharging characteristics, and increased cycles, or lifespan. Additionally, costs go down the more that battery technology improves, so in the next few years, expect to see electric vehicles that charge faster, drive farther, last longer, and are cheaper to produce and buy.