German engineers at Karlsruhe Institute of Technology copy nature to speed the manufacture of lithium-ion batteries used in electric vehicles.

By employing the same physical-chemical process that transports water in trees, the researchers say they have solved a problem conventional production methods encounter: getting enough electrolyte into the huge number of micrometer-sized pores in battery electrodes.

“The pores have to be filled completely with electrolyte in order to work optimally,” physicist Wilhelm Pfleging says.

“Without electrolyte, there is no charge equalization inside and no current flow outside” the cell, he says.

Conventional EV battery materials make wetting of the electrode pores difficult.

An expensive, time-consuming storage process is needed to force electrolyte into the pores to maximize battery capacity.

The engineers are using mechanical-chemical technology that changes the electrodes so they draw electrolyte into the battery the way water is sucked into high trees.

This enables electrolyte to spread rapidly over the electrodes and improves performance.

“Our new process allows (us) to reduce this time from several hours to a few minutes,” Pfleging says.

The researchers also claim their method lowers the expense of manufacturing Li-ion EV batteries.

The institute, which unveiled the technology at the recent eCarTec International Electromobility Fair in Munich, has patented the process and says several battery makers have requested permission to license the method.