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When hybrid batteries make headlines – whether it’s a new 200-mile range battery or a company expanding its battery manufacturing – the news typically focuses on lithium-ion if not some advanced tech touted with varying degrees of potential.
But lithium-ion (li-ion) might not be the best battery technology to invest in for electrified vehicles says one maker of the technology that came before and which is still used in most of Toyota’s hybrids.
BASF, the world’s largest chemical producer, is wagering that nickel metal hydride (NiMH) can create a more efficient battery than li-ion. The company is working to significantly multiply the capacity and improve packaging for a better rechargeable battery.
“[BASF] recently doubled the amount of energy that these batteries can store, making them comparable to lithium-ion batteries,” said Kevin Bullis in MIT Technology Review.
“And they have a plan to improve them far more, potentially increasing energy storage by an additional eight times.”
When electrified vehicles started become mainstream, NiMH was the rechargeable battery of choice. Its advantages over li-ion include cost, lifespan and safety.
NiMH is also said to be less susceptible to extreme temperatures. On a Tesla Model S, which uses li-ion batteries, at least one owner has carefully documented that range can drop by as much as 40-percent in subzero weather.
Though li-ion has increased in popularity, it’s not the only battery technology used in electrified vehicles. Currently, popular hybrid models including the automaker that owns 70 percent of the hybrid market – Toyota/Lexus – has stuck with its tried and true formula so far.
“For more than a decade, NiMH batteries have delivered safe, reliable, cost-effective performance in more than five million hybrid electric vehicles,” said Michael Zelinsky, market and business development manager for BASF Battery Materials.
“NiMH batteries consistently deliver life-of-vehicle performance and owners seldom give them a second thought, regardless of driving conditions.”
While it’s cheaper to build a NiMH battery, the resulting pack historically takes up more space and weighs more than Li-ion. This is also part of the standard that BASF wants to change.
“Changing the microstructure helped make them more durable, which in turn allowed changes to the cell design that saved considerable weight, enabling storage of 140 watt-hours per kilogram,” Bullis said.
If BASF is able to meet its goal of developing a NiMH battery that costs $146 per kilowatt-hour, the battery will be half the cost of a comparable Li-ion battery. Extra cost and weight savings will also come from dropping the safety requirements needed for Li-ion batteries.
“Nickel-metal hydride batteries wouldn’t require the heavy, expensive safety systems needed by the lithium-ion batteries used in electric cars now,” said Bullis.
Analysts agree that battery cost is key to the sales success of electrified vehicles. By lowering the cost of the rechargeable battery – which makes up a significant portion of an electrified vehicle’s price – the purchase price of a new hybrid or battery electric vehicle can become more affordable.