Electric cars aren’t really anything new, but recent developments in battery technology have made mass-production electric cars a reality. Indeed, if it wasn’t for such improvements, electric car batteries would simply be too big, too heavy, and too high-maintenance for the average driver, even the most tech-savvy.
Whereas electric cars simply replace the engine, transmission, and fuel tank for electric motors and electric car batteries, one simply doesn’t drop in a dozen car batteries, an electric motor, and some control modules. Actually, one can do this, and plenty of do-it-yourselfers have done exactly that, with some pretty impressive results. Still, such easy car care DIY modifications aren’t nearly as reliable and “foolproof” as a production vehicle should be, which is why it’s taken so long for electric cars to go mainstream.
A Big Heavy Problem
To understand the problem, one needs to understand the battery chemistry issues, but we’re not going to bore you with a chemistry lesson – simple energy-density lesson will suffice. Today, unless you already own an electric car, a “car battery” is that heavy 12 V lead-acid (LA) battery under the hood or in the trunk.
For starting the internal combustion engine, LA batteries are well-suited, as they provide a lot of energy to start even big engines in cold weather. Though they can provide a lot of energy for starting, the engine doesn’t run on this battery – that’s the job of the alternator. You could string a bunch of LA batteries together to run an electric motor, but you would run into a few problems: limited range, excessive weight, and possible deep-cycle battery damage.
For short-range vehicles, like golf carts and fork-lifts, lead-acid batteries work quite well, but a road vehicle travels much farther and much faster, requiring much more battery capacity. You could add more batteries to get more range, but eventually these would weigh so much that any range increases would be cancelled out.
Electric Car Batteries Through the Years
At first, in the late 1800s, electric car batteries were constructed of simple non-rechargeable cells, but these would soon be replaced by rechargeable lead-acid cells, much like we’re already used to seeing. By 1900, 30% of all vehicles on the road were electric cars, but the availability of gasoline and inexpensive cars – Ford Model T started it – pushed research into better battery technology to the back burner.
It wouldn’t be until the 1970s that interest in electric cars would be renewed, and the development of higher-density batteries was a major factor. Nickel-cadmium (NiCd) cells were about 50% more energy-dense than lead-acid, but were eventually banned because cadmium is toxic. Nickel-Metal-Hydride (NiMH) batteries are about 200% as energy-dense as lead-acid, and were first implemented in Toyota Prius and Honda Insight hybrid electric cars. Still, an NiMH electric car battery pack would simply be too heavy to get much range improvement.
Lithium-ion (Li-ion) and Lithium-Iron-Phosphate (LiFePO4) cells have so far provided the biggest boost in energy density, between 300% and 400% more energy-dense than LA batteries. Nissan Leaf, all Tesla vehicles, and most other electric cars and hybrid electric cars use Li-ion battery packs, though a few hybrid and electric car startups are toying with LiFePO4 chemistry.Tags: car batteries