New EV battery concept could put an end to range anxiety

26 Jul 2016

Researchers working on lithium-ion battery technology believe they have found a solution to the problem of limited range in electric vehicles (EVs) using a relatively simple method.

Those who drive EVs, or know enough about them, have probably heard of the phrase ‘range anxiety’, referring to fears that a driver could be left stranded by an EV’s limited driving range.

However, developments in lithium-ion battery technology used in EVs – the exact same type which are found in almost all rechargeable devices today – have seen range increased substantially to around 2,500km on a single charge.

Five volts instead of four

Despite advancements in battery technology in recent years, many EVs still pale in comparison to more widespread, cheaper internal combustion engine (ICE) cars, but new research findings could remedy this.

Researchers at the University of Tokyo believe they have found a solution that could eliminate range anxiety by using a lithium-ion battery that uses a battery voltage of five, rather than the current four.

Until now, 5V batteries have not been used in EVs because, compared with the lower 4V, they experience a severe capacity loss of more than 50pc after only 100 charge-discharge cycles.

Publishing their findings in the journal Nature Communications, the Japan-based team developed a 5V battery that uses a super-concentrated lithium-based electrolyte from stable lithium salt in a solvent at an extremely high concentration. Where a less-concentrated solution suffers from high capacity loss, the peculiar 3D liquid structure of this new electrolyte does not.

Much safer than current batteries

Another advantage provided by this new 5V battery is that it’s much safer than current lithium-ion batteries – which explode when the interior comes into contact with water – because it has a much higher thermal stability compared to more dilute electrolytes.

From a manufacturer’s perspective, this 5V battery would also have benefits to an EV aside from an increased range as the reduced number of cells would decrease the size and weight of the whole battery pack.

There is one drawback, however, in that the current method of creating such a super-concentrated electrolyte is rather expensive compared with the 4V battery, but researcher Atsuo Yamada sees this as a problem that can quickly be overcome.

‘Cost will not be a problem in the future’

“At present, the biggest challenge is materials cost, because the [new stable lithium] salt is currently more expensive than currently used [unstable lithium] salt,” Yamada said.

“However, the mass production of the [new stable lithium] salt has recently been initiated and is becoming increasingly available at much lower cost. Hence, we expect that the cost will not be a problem in the future. Moreover, the cost of electrolyte is only less than 7pc of the total battery price.”

The research team’s next objective is to improve battery performance and better understand the new electrolyte’s unusual characteristics.

EV charging image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic