Measurement techniques of lithium-ion batteries

Abstract

The focus of this work is firstly to take a little dive into what battery is, what it is made of, and how it works. Then focus on the main objective of this work, study different battery measurement techniques and do battery testing on batteries to find out what kind of results each one of these gives.

This work is mainly focusing on three different techniques: Electrochemical Impedance Spectroscopy (EIS), capacity-, and battery cycle life -testing. Finding out what these tests actually measure form batteries, and what information these tests give us.

In testing we run EIS and capacity test before and after the life cycle tests to get reference points about how the cycle testing has affected the batteries.

Equipment that are being used for these tests are Arbin Instruments’ MITS Pro 8 as the main test equipment for capacity and life cycle tests. For EIS analysis we need to have separate device, and for that, Metaohm Vionic is being used.

Results supported our expectation pretty well, cycle life testing degraded batteries and when testing their performance after that, all of the batteries could only give just about half of the energy than before. Surprisingly 20 cycles were enough to degrade batteries this much. Hypothesis was that we would need 100 if not 100s of cycles before we could observe this much degradation