What next for car and EV batteries?

Lithium-ion batteries will dominate the automotive scene over the coming ten, and possibly 15, years, but some odd-ball technologies could push their way through, according to market research firm IDTechEx.

“During that time we shall see peak Pb-acid battery, the biggest nail in its coffin being when electric vehicles more widely abandon them and even those conventional vehicles modified to stay legal under impending carbon dioxide laws abandon them, relying totally on lithium-ion units,” said the firm.

The odd-balls include lithium-sulphur and flow-batteries.

“We have closely assessed the research and see lithium-sulphur in the lead but with considerable challenges to overcome, such as life and volumetric energy density,” said IDTechEx.

Flow-batteries separate energy and power capacity by storing energy in the form of active chemicals in tanks for anolyte and the catholyte (whose size determine energy capacity) and these are pumped into a battery/fuelcell unit (whose size determines power output) when electricity is required. The same unit re-charges the chemicals when spare electricity is available.

Describing flow-batteries as a wild card, IDTechEx said: “Most people rightly see these as very large units suitable for grid applications such as peak shaving but one or two organisations are thinking the unthinkable about putting them in cars because they are headed for $100 per kWh and size and weight might just fit the bill in due course. Toyota’s advanced research people told us recently that they would not dismiss the possibility.”

German start-up Nanoflowcell has been exhibiting sports cars it says will use 48V flow-batteries and achieve 1000 miles electric range. “That voltage is counter to received understanding on design of car powert-rains. Pure electric cars are generally headed up towards 800V for light weight and performance,” said IDTechEx in an aside. It sells a report: ‘Mild Hybrid 48V Vehicles 2016-2031’.

The cell in the Nanoflowcell case cannot re-charge its liquids, so these are pumped into the car, then pumped out when spent and recycled externally.

“Flow battery technology is immature. There is everything to play for and although pumping liquids from reservoirs does not sound compact or reliable in a car but who knows? Watch this space,” said IDTechEx.

The firm is offering two reports covering the future of road vehicle batteries:

Image source Nanoflowcell via IDTechEx