Research center Imec has said it has doubled the energy density of its solid-state Li-metal battery cell and started scaling up a pilot line for manufacturing the cells, paving the way for longer range electric vehicles.

Making the announcement at the European Electric Vehicle Batteries Summit in Berlin this week, Imec said its battery cell has achieved an energy density of 400 Wh/liter at a charging speed of 0.5C (2 hours). The organization's engineering roadmap for solid-state batteries says it will surpass wet Li-ion battery performance and reach 1000Wh/L at 2-3C by 2024.

Today’s rechargeable Li-ion battery technology still has room for improvement, but not enough to significantly improve the range and autonomy of electrical vehicles. Hence, Imec’s researchers are working to replace the wet electrolyte with a solid material, which provides a platform to further increase the energy density of the cell beyond that of cells based on liquid electrolyte.

The solid nanocomposite electrolyte that the R&D center has developed has an exceptionally high conductivity of up to 10 mS/cm with a potential for even higher conductivities. A distinguishing feature of the new material is that it is applied as a liquid — via wet chemical coating – and only afterwards converted into a solid when it is already in place in the electrodes. That way it is perfectly suited to be casted into dense powder electrodes where it fills all cavities and makes maximum contact, just as a liquid electrolyte does.

Using that solid nanocomposite electrolyte in combination with a standard lithium iron phosphate (LFP) cathode and lithium metal anode, Imec says it has now fabricated an improved battery with a record combination of energy density and charging speed for a solid-state battery.

Imec’s solid state battery cells [Image: Imec]

In addition, Imec has commenced the upscaling of the cells in a state-of-the-art lab for this new solid-state battery technology, including a 300 square meter battery assembly pilot line which includes a dry room of 100 square meters. This conventional A4 sheet-to-sheet wet coating-based line is suited to processing of Imec’s solid electrolyte.

The assembly of the new cells could be done by slight modification of existing manufacturing lines for Li-ion batteries. This means the new technology would not need expensive capital investments to switch from wet to solid-state cells. The new pilot line is located at its partner the EnergyVille Campus in Genk (Belgium); another is set-up with the university of Hasselt. These lines can produce prototype pouch cells of up to 5Ah capacity. The EnergyVille line is ready to become a cornerstone for research groups and companies doing R&D projects on these batteries.

“The new battery demonstrates that our breakthrough electrolyte can be integrated in performant batteries. The pilot-line allows us to take the next step and upscale the battery breakthrough to industrially relevant processes and formats, using manufacturing processes similar to those for wet batteries,” said Philippe Vereecken, scientific director at Imec/EnergyVille.

Imec’s battery R&D is a collaborative program for open innovation to which it says it invites all interested parties.