At some point in the future, we’re pretty sure historians will call the current period of history we’re living in the lithium-ion age, because lithium-ion battery packs are used in everything from electric car battery packs and laptop computers to gadgets, medical devices and telephones.
Not so long ago however, nickel-metal-hydride batteries were the preferred chemistry of the humble rechargeable battery pack, thanks to their lower cost and long life. Look back at any of the first-generation plug-in cars produced at the turn of the last century — the Toyota RAV4 EV or late-model GM EV1 for example, — and you’ll find nickel-metal hydride battery packs providing the grunt needed to power these legendary vehicles.
These days, nickel-metal-hydride battery packs are only found in a handful of hybrid vehicles — like Toyota’s legendary family of Prius hybrids — and the occasional low-volume electric vehicle, but as our friends over at GreenCarReports detail, that could soon change thanks to a promised ten-fold increase in NiMh battery capacity being talked about by German chemical supplier BASF.
According to a recent post over at Technology Review, BASF’s team of scientists who work at its dedicated research centre have been working hard to change the microstructure of the electrodes used in nickel-metal battery packs, making it far more energy dense and durable. The result? it needs less electrode material for a given power output and storage capacity.
They claim already to have produced NiMH cells in a laboratory environment with an energy density of 140 watt-hours per kilogram. While that’s less than 230-240 watt-hours that some lithium-ion cells can produce, NiMH is inherently more stable as a battery chemistry, requiring less safety failsafes than lithium-ion.
In an automotive application for example, the weight saved by choosing NiMH over lithium-ion could represent a sizeable improvement in overall efficiency, and with NiMH battery packs known to suffer less from premature ageing and degradation with time, opting for NiMH rather than lithium-ion could pay dividends for an automaker willing to support BASF in its research.
At the moment, BASF says it believes it can continue to work on increasing the energy density of its NiMH test cells, resulting the kind of energy density never-before imagined for that particular chemistry. If it succeeds — with a figure of around 700 watt-hours per kilogram — it would also place NiMH back in the spotlight as the chemistry of choice, since a ten-fold increase would place it way ahead of current lithium-ion technology.
In addition to dramatically increasing the storage capabilities of an automotive battery pack by an order of magnitude while reducing its weight by an equally large amount, the kind of developments being researched by BASF could very well pave the way to cars that could travel more than 1,000 miles on a battery pack the same size as the ones in today’s mid-priced electric cars.
At that point, the use of hydrogen fuel cells and indeed any kind of fossil fuel, would become something of a moot point for most car drivers.
There’s only one problem: at the moment, this technology and the promises being made are stuck in a laboratory environment. Just like so many other battery breakthroughs we’ve told you about in recent years, it’s a long way from the laboratory to the automotive factory.
It’s worth remembering too that BASF is researching other battery technologies too at the same time, like advanced lithium-ion cells.
That said, BASF isn’t a small research company and unlike other battery breakthroughs we’ve covered, has a fighting chance of bringing this technology to market.
Watch this space.
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