Why Toyota Still Uses Ancient Nickel Metal Hydride Technology In Hybrids

Certainly we keep using NiMH batteries because they have been a hallmark product for our hybrid electric vehicles. However, your article seems to imply that the technology is old and outdated, when, in fact, we have continued innovating in this space and have started using a completely new NiMH battery in our vehicles.

An example is our latest Aqua, a vehicle not sold in the U.S., but the battery used in it could hypothetically make its way here in other vehicles. The new Aqua is equipped with a high-output bipolar NiMH battery.

Bipolar batteries are advantageous because they have a greater active surface area with a lower resistance, allowing larger current flow and increased output. These changes mean improved accelerator response and better, more powerful acceleration from low speeds. Of course those aren't the only advantages: the new bipolar battery will also help extend the drivable range.

Finally, when looking at the new bipolar battery vs the previous NiMH batteries we were using, the new battery is designed to deliver 1.5 times greater output per cell. This means you can offer the same level of output with less cells, or you can keep the pack the same size and have much greater output for the vehicle.

While it might seem stale and no longer current with a lot of other OEMs making vehicles with Li-ion, there is something to be said about the safety and reliability of NiMH and the ability to continue to innovate and improve these types of batteries. It is precisely because of our long experience in this technology that we are able to keep using and improving them.

I'd rather have a NiMH battery in cold climates. But that's just me.

All states now get the 10 year 150,000 mile hybrid battery warranty.

Per Toyota "Starting with the 2020 model year, every hybrid battery warranty is being increased from 8 years or 100,000 miles, to 10 years from date of first use, or 150,000 miles whichever comes first."

"The term "tried and true" rings throughout the halls of Toyota. Another common saying is, "if it ain't broke, don't fix it.'"

True words for sure. It is this lack of innovation that will drive Toyota out of business as the auto industry turns to EVs. Tesla is on the road to business success while Toyota is on the road to bankrupty.

But yeah, they're good at "tried and true."

My '09 Escape Hybrid has about 170,000 miles on it and still gets as good mileage as when I bought it. Mileage would be reduced by lower capacity of the battery pack because I commonly exceed the battery's capacity limits. The battery is NiMH. So unless the battery had capacity initially set aside to be used as the battery ages, to maintain performance, the battery has not degraded. I note that occasionally and automatically it performs a "conditioning cycle" on the battery, which I sometimes notice happening but know little about.

Whereas I understand Lithium-ion batteries lose capacity over time whether they are used or not.

Toyota is pretending they have reinvented NiMH, But I am not aware of any manufacturer that has gone back to NiMH battery power. NiMH has memory issues that Li-ion doesnt. Li-ion is also easier to charge than NiMH since there is a clear voltage change of the cell as it reaches full charge. If it is better, why doesn't Toyota offer a full battery warrenty in all states?

NiMH isn't ancient, it's invention and progression mirrors lithium ion almost exactly. The two technologies are literally the exact same age. In some ways, and using a literal definition, NiMH is actually newer tech. The first lithium ion cell was invented in 1965. The first NiMH in 1967, making NiMH a newer technology literally speaking. But the first consumer grade lithium ion hit the market in 1991, while the first consumer grade NiMH in 1989, both are 30 years old. But we don't use the same materials anymore. Theres been advancements since. Most quality NiMH produced today are Low-Self Discharge models, a technology invented in 2015. Meanwhile, most lithium ion batteries powering EV's today are still Nickel Manganese Cobalt Oxide cells, a technology invented in 2001. You could go back and forth like this forever, with different advancements at different times, but you can't call NiMH ancient when they both were invented and hit the market within 2 years of each other.

NiMH isn't ancient technology, its a different technology. In some ways its superior to lithium batteries (they are more durable and have a longer life span overall). In some ways its inferior (the memory issue is most concerning, yet can be resolved by full discharge and recharge, the memory issue is not a longevity issue).

Who knows, when lithium supply runs thin, and before some truly newer and fantastic battery tech comes out, we might need to switch back to nickel batteries. Nickel is more abundant and highly recyclable.