Solid-State Batteries Hold Promise for Future EVs

Solid-state batteries are gaining momentum for possible use in next-generation electric vehicles, according to speakers at a recent battery conference in Novi, Mich. During a session entitled "Advanced Lithium-Ion and Beyond," panelists noted that sodium-sulfur and other solid-state-type batteries could improve energy density and safety compared with current lithium-ion systems.

Sodium-sulfur is considered to be the front runner, experts from carmakers, battery manufacturers and national laboratories agreed. Improvements in the construction of the electrolyte have been promising, with several companies recently claiming breakthroughs. But panels said such batteries need a longer lifecycle to be practical.

The chemistry uses low-cost materials with an energy storage capacity as much as five times that of lithium-ion batteries. The goal is a cost of $100 per kWh, according to Levi Thompson, director of the University of Michigan's hydrogen energy technology laboratory. That would make sodium-sulfur batteries less than half the price of the lowest-cost lithium-ion batteries today.

Until now, most of the development work in solid-state batteries has focused on the microelectronics market, notes Andy Keates, principal engineer, energy storage technology at Intel Corp.. But he expects the battery's cost benefits to eventually lead to automotive applications too.

Robert Bosch GmbH recently acquired Seeo, Inc., a startup developing a form of solid-state batteries with a solid electrolyte and lithium anode. Bosch expects the batteries to be available by 2020 with an energy density double that of current lithium-ion packs.