Toyota Motor Corporation has developed a method for observing the behaviour of lithium ions (Li-ions) in an electrolyte when a Li-ion battery charges and discharges.

By using this method, it is possible to observe in real-time, the deviation of Li-ions, one of the causes of deterioration in the performance of Li-ion batteries.

Toyota believes this will provide essential guidelines for R&D that aims to improve the performance and durability of batteries, which would lead to longer battery life, as well as longer driving ranges for plug-in hybrid vehicles (PHVs) and electric vehicles (EVs).

Li-ion batteries use a metal oxide in the cathode, a carbon material in the anode and an organic electrolyte for the electrolyte. Lithium ions flow in the electrolyte from the cathode to the anode when the battery is charging and from the anode to the cathode when the battery is discharging, which results in an electric current flow.

Li-ions play an essential role within the electrolyte during battery charging and discharging.

It has been known Li-ion deviation occurs in the electrodes and electrolyte as a result of charging and discharging and such deviation has been believed to limit the usage area of batteries, which is one factor that reduces the area in which the maximum performance can be achieved.

When investigating the mechanism of Li-ion deviation, however, confirming the behavioru of Li-ions in the electrolyte under the same environment and conditions as when it is being used in related products was not possible using existing methods