A CINE team has developed a method to determine accurately and in a few seconds the amount of energy stored within a battery – the state of charge. The technique can also be used to supervise battery aging.

The method is applicable to batteries of all types, rechargeable or not, from lithium batteries, which are widely used today, to sodium or lithium-sulfur technologies, which are still under development. Another advantage of the technique is that it works both during battery charge (when it stores energy) and during discharge (when it delivers electricity). In addition, the method can be used to monitor parameters of a battery aging to better predict the end of its lifespan and the cause of it.

“Unlike traditional methods that only measure how much electric charge enters and how much leaves the battery over time, this method monitors how the electrochemical parameters of the cell vary in charge and discharge and also with the battery at rest,” explains Rodolfo Castanho Fernandes, collaborating researcher at CINE. Because of that, devices based on the new method can both establish the state of charge and determine what components are aging within it.

Based on this method, the team of researchers has developed a device that can be coupled to batteries of all sizes, inside or outside them. The device could be used in electric cars, electric tools, smartphones etc.

The work was carried out at Unicamp by Fernandes with the doctoral student Érick Alves Santos and Professor Hudson Zanin – all members of CINE’s Advanced Energy Storage Program.

A patent application on the method and device was filled in December last year at the Brazilian National Institute of Industrial Property (INPI).

Patent Request Reference: Método de estimativa do estado de carga por espectroscopia de impedância eletroquímica em baterias em operação e respectivo sistema de monitoramento de baterias. Process Number: BR 102022026239-0. Inventors: Rodolfo Castanho Fernandes, Érick Alves Santos and Hudson Giovani Zanin.

Contact for more information: rodolfoc@unicamp.br and hzanin@unicamp.br