Evaluation of internal and external sensor measurements for determining the state-of-charge and state-of-health of Li-ion pouch cells

摘要

Owing to the construction, Li-ion cells can cause dangerous situations if they are not operated properly. Therefore, battery management systems must obtain the state of the battery as accurately and fast as possible. Temperature and pressure sensors can help to determine the state of health and the state of charge of the cell and detect over temperatures and over pressures immediately. The change of stiffness of the anode and cathode material during charging and discharging can be derived by measuring the time of flight of vibrations that are sent through the battery. In this work, several methods to determine the state of charge and state of health are analyzed and their accuracy and feasibility are discussed.