A fast-charging lithium-carbon battery systemEngineering360 News Desk | September 28, 2021
A new battery technology unveiled by Mahle Powertrain and Allotrope Energy reportedly delivers ultra-fast charging coupled with good power density. By combining the benefits of super capacitors and traditional lithium-ion batteries, the lithium-carbon technology should enable a full charge to be delivered in a similar time to refueling an internal combustion-powered vehicle. In addition, lithium-carbon cells are free from rare-Earth metals, are fully recyclable and are not susceptible to runaway events.
As part of the collaborative project, Mahle Powertrain examined how an electric moped could be used as an urban delivery vehicle powered by an inexpensive small capacity lithium-carbon battery. The study centered around a city-based e-moped fast-food delivery service with a 25 km target range. A 500 Wh conventional lithium-ion battery would require a recharge mid-shift that, even with a fast-charger, would take more than 30 minutes. In addition, regular fast-charging reduces battery life to the point it would likely need replacing every year or two. A lithium-carbon pack, however, could be recharged at 20 kW in just 90 seconds, meaning a full charge could be achieved in the time taken for the next delivery to be collected.
Allotrope Energy’s lithium-carbon technology features a high-rate battery-type anode and a high-capacity electric double layer capacitor-style cathode, separated by an organic electrolyte. The result is a battery cell that apparently suffers none of the thermal degradation effects experienced by traditional lithium-based batteries. Its stability, even at high temperatures, permits high current delivery and fast recharging, all without the need for complex external cooling or elaborate battery management systems.
The capacitor-style cathode enables a lifetime of over 100,000 cycles, far greater than conventional batteries. A built-in capacitor-based energy store deliver ultra-fast charging up to 20 kW by augmenting the power from a typical 7 kW single phase connection, thereby reducing cost and complexity while eliminating the need for expensive power grid connection upgrades.