By Prof. Tetsuya Osaka, Institute for Research Organization for Nano & Life Innovation, Japan.
The energy-sustainable society by energy storage with high energy density requires a diagnosis system to evaluate batteries for safety and reuse. We have developed a square current electrochemical impedance spectroscopy (SC-EIS) technique for the battery diagnosis, in particular for LIB (Lithium Ion Battery).
EIS (Electrochemical Impedance Spectroscopy) has been utilized to characterize each elemental process of electrochemical devices, because it enables us to analyze dynamics of each elemental process sensitively and separately without destruction of the cell . The conventional EIS using frequency response analyzer (FRA) with potentiostat system is not easy to measure the impedance of the large-scale LIB because of its low internal resistance. Moreover, FRA with potentiostat system for conventional EIS measurement could not be mounted on the vehicle. Thus, the impedance measurement system is needed without using FRA with potentiostat system. We developed the application of square wave as input signals of EIS to the EMS (Energy Managing System), of which a new technique is designated as “Square-current electrochemical impedance spectroscopy (SP-EIS, SC-EIS)”. We applied the new method of SC-EIS to evaluate a state of a commercial storage battery system with LIB . By the new method, we were able to measure the EIS for large scale LIB system (see Fig.1). The example data are shown in Fig.2.
 T. Osaka et al., J. Power Sources. 205 (2012) 483–486.
 T. Yokoshima et al., Electrochim. Acta. 246 (2017) 800–811.
Tetsuya Osaka is Senior Research Professor and Emeritus Director of the Institute for Research Organization for Nano & Life Innovation, and Professor Emeritus of the Faculty of Science and Engineering, Advisor to the Office of the President, Waseda University, Tokyo, Japan. He is past President of the Electrochemical Society (ECS), also was serving as President of the Magnetics Society of Japan, President of the Electrochemical Society of Japan, President of Japan Institute of Electronic Packaging, Vice-President of the Surface Finishing Society of Japan, Vice President of the International Society of Electrochemistry (ISE).
The recent works focus on a newly “electrochemical nanotechnology”. His technical contributions have been recognized by many awards including Medal with Purple Ribbon bestowed from the Decoration Bureau of the Cabinet Office, Japan, in 2010, Prizes for Science and Technology in Development Category of the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology in 2008, and so on.