EV battery developed to overcome ‘range anxiety’

Chao-Yang Wang's lab, Penn State

Range anxiety, the fear of running out of power before being able to recharge an electric vehicle (EV), could soon be consigned to history, according to a team of Penn State University engineers which has been developing lithium-iron phosphate batteries with a range of 250 miles that can be recharged in only 10min.

Lead research Chao-Yang Wang said: “We developed a pretty clever battery for mass-market electric vehicles with cost parity with combustion engine vehicles. There is no more range anxiety and this battery is affordable.”

The researchers also say that the battery should be good for two million miles in its lifetime.

In a report in Nature Energy the researchers say that the key to long-life and rapid recharging is the battery's ability to quickly heat up to 140°F, for charge and discharge, and then cool down when the battery is not working.

The self-heating battery uses a thin nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. Once electrons flow it rapidly heats up the nickel foil through resistance heating and warm the inside of the battery. Once the battery’s internal temperature is 140°F, the switch opens and the battery is ready for rapid charge or discharge.

Mr Wang’s team modelled this battery using existing technologies and innovative approaches. They suggest that using this self-heating method, they can use low-cost materials for the battery's cathode and anode and a safe, low-voltage electrolyte.

The cathode is thermally stable, lithium iron phosphate, which does not contain any of the expensive and critical materials like cobalt — it is made from very large particle graphite, a safe, light and inexpensive material.

Because of the self-heating, the researchers said they do not have to worry about uneven deposition of lithium on the anode, which can cause lithium spikes that are dangerous.

Mr Wang explained: “This battery has reduced weight, volume and cost. I am very happy that we finally found a battery that will benefit the mainstream consumer mass market.”

According to Wang, these smaller batteries can produce a large amount of power upon heating — 40kW hrs and 300kW of power. He said that an EV with this battery could go from zero to 60mph in 3sec and would drive like a Porsche.