The latest on EV battery technology from the experts (part 1)

There is no denying that electric vehicles are now a part of modern transportation. It wasn't long ago that an electric car on the road was somewhat of an anomaly or a curiosity. Now sitting at a red light, you are likely to have an electric city bus, a Tesla and a couple of hybrid vehicles surrounding you. Part of the increased adoption of electric propulsion has come from EV car battery technology breakthroughs. Electric car battery technology has evolved rapidly in the past several years. Let's discuss advances in EV battery technology, and look at the roadmap for where emerging tech and EV battery power is taking the industry.

Old-school ev battery technology

Early EV battery designs were little more than banks of lead-acid batteries, much like what you would find on a golf cart. Lead-acid batteries are relatively cheap and tough, so they work well in a car. There's a reason why almost every vehicle on the road has a lead-acid battery under the hood for starting - dependability. Many pure electric vehicles even have a 12-volt lead-acid battery as a power source, apart from the main drive battery. The downside is that lead-acid batteries weigh a lot. That's okay if you only need one, but if you need a whole stack of them, the weight penalty adds up quickly. For example, the 1997 Chevrolet S-10 Electric battery pack weighed 1,400 pounds!

Early fully-electric vehicles, such as the RAV4 EV, and hybrids, such as the Toyota Prius and Ford Escape, used NiMH (nickel–metal hydride) batteries. NiMH can handle a lot of charge/discharge cycles before they start to degrade. They offer excellent power output, but have a tendency to lose charge as time passes when not in use. NiMH batteries also don't like extreme temperatures. NiMH is still popular for hybrid vehicles, but pure electric vehicles have mostly moved on to newer battery technology.

Current battery technology

Today, most electric vehicles use some form of lithium-ion battery for the main drive system. Yes, the same kind of battery found in your laptop or cordless drill can also get you from point A to point B. Lithium-ion batteries charge quickly and offer high-energy density, which is important when trying to cram a battery pack into a vehicle. They also weigh a lot less than a comparable lead-acid battery.

Unfortunately, lithium-ion batteries don't like extreme temperatures. Extreme cold slows down charging time, while extreme heat degrades the battery itself. Vehicles like the Nissan LEAF had dense battery packs with no ability to regulate temperatures, while Tesla vehicles use a liquid temperature-controlled battery pack. By using liquid to cool or warm a battery pack, it can remain at the optimum operating temperature. This is why you might notice an electric vehicle with a radiator in the parking lot, which cools the battery the same way it does an internal combustion engine.

Another problem with lithium-ion batteries is what to do with them once they are no longer able to hold a charge. Recycling is difficult at this time, but not impossible. Materials inside the battery also have a nasty tendency to catch fire when exposed to water, making disassembly a touchy procedure. Traditionally, recycled lead-acid batteries are shredded to separate their components, but lithium-ion batteries require a gentler touch to reclaim their ingredients. One potential recycling method uses a shredder submerged in a special liquid that prevents the possibility of fire.

See part two of this article in a future issue of The Loop newspaper.

Don's Pro Technology is located at 230 E. Tehachapi Blvd., in Tehachapi and can be reached at (661) 822-1600.