Seemingly overnight, gas-electric hybrid vehicles have gone from pipe dream to mainstream. But for many consumers, tough questions about the “electric” part remain. Hybrids use electric motors that are powered by battery packs, and everyone knows batteries don’t last forever. Think about laptop batteries, or cell phone batteries: after a couple years you’ll need a replacement. Could the battery packs in hybrid cars really be that different?
The short answer, it turns out, is an emphatic “Yes.” Based on available evidence, hybrid drivers should enjoy many years of trouble-free motoring from their complex power systems.
But let’s delve deeper. Here, we explain what these battery packs are and how they factor into the hybrid ownership experience.
We’ve been hearing about the automotive ascendancy of lithium-ion batteries—the default power source for consumer electronics—for years, but most gas/electric hybrid vehicles on the road today use nickel-metal hydride (NiMH) battery packs. NiMH batteries are less toxic inside than traditional lead-acid batteries, so that’s an environmental bonus. But here’s the real story: NiMH batteries are at once more space-efficient than traditional lead-acid batteries, and much cheaper than lithium-ion batteries.
We do expect lithium-ion batteries to become more prevalent in hybrids as time goes on. Due to their superior efficiency, they’re already featured in cars with energy-hungry full-electric modes, such as the Chevrolet Volt and Nissan Leaf. And even in the conventional gas/electric hybrid market, lithium has been making considerable headway thanks to recent arrivals like the Ford C-Max Hybrid and Fusion Hybrid, the latest Honda Civic Hybrid, the Hyundai Sonata Hybrid, and the Volkswagen Jetta Hybrid.
But for now, NiMH remains the proven champ, a jack-of-all-trades on which Toyota—far and away the leader in hybrid market share—continues to depend.
Have you heard the one about how your computer or cell-phone battery will last longer if you neither charge it fully nor allow it to run down to zero? Believe it or not, that’s absolutely right. But hybrid vehicles are one step ahead of you: they have applied safeguards that limit both the maximum and minimum charge levels of the battery pack. This ensures that the battery pack will provide meaningful motive assistance without conking out prematurely, no matter how you treat your car.
But just when will a typical NiMH battery pack conk out? We asked Toyota Product Communications Specialist Moe Durand to share the company’s insights thus far.
“All Toyota batteries are designed and built to last the life of the vehicle,” Durand said. “We have seen first-generation Prius batteries with over 200,000 miles on the pack that are still on the road.”
As far as specific battery pack failures go: “We can’t share specific numbers,” he replied, “but we can say that the number of replacements is extremely low—less than 5% of the packs in use.”
Your mileage may vary, of course, and although each competitor in this space has proprietary hybrid technology, we’re comfortable saying that NiMH battery packs in general are a mature product at this point, with millions of miles and countless refinements already on the books. Put it this way: if you’re not concerned about engine failure in a new car, you shouldn’t fret about NiMH battery-pack failure, either.
Regarding lithium-powered battery packs, however, they’re relatively new arrivals, so there’s not much real-world durability data. It will be interesting to see how the lithium-based hybrid offerings from Ford, Honda, Hyundai, and Volkswagen fare over time, not to mention true electrics like the Leaf.
The End of the Line
Say your battery does meet its end. What then? Firstly, almost every gas/electric hybrid comes with a lengthy battery-pack warranty for your peace of mind. Manufacturers like Toyota and Ford offer warranties covering you for at least 8 years or 100,000 miles. Hyundai goes even further, offering lifetime battery-pack coverage for original Sonata Hybrid owners. Honda’s official line is that the “battery-pack limited warranty may vary,” but in practice, models like the Insight routinely receive 8-year/80,000-mile coverage for hybrid components. The outlier is Volkswagen, which provides a relatively stingy 5-year/60,000-mile warranty for the Jetta Hybrid’s batteries.
There’s also good news for the environment. Recycling hybrid batteries can actually pay, as the “rare earth” elements in otherwise unsalvageable battery packs command strong prices. Policies vary in detail—Toyota, for example, puts a toll-free number on every battery pack to ensure that it will come back to the company for processing, while GM and Nissan have pursued repurposing agreements with power companies—but a basic commitment to recycling is largely shared across the industry. You can rest assured, then, that when your battery pack does meet its maker, the green karma accumulated during its lifespan won’t be reversed by what comes next.