Electrothermal impedance spectroscopy measurement on high power LiMO2/Li4Ti5O12 battery cell with low bandwidth test setup

Modern lithium-ion batteries, like LiMO₂/Li₄Ti₅O₁₂ chemistry, are having very high power capability, which drives the need for precise thermal modelling of the battery. Battery thermal models are required to avoid possible safety issues (thermal runaways, high-temperature gradients) but also for the optimal battery pack design and for predicting battery electrical performance during operation (especially at low temperatures). Equivalent electrical circuit battery models (thermal and electro-thermal) are able to offer relatively good performance with relatively low computational efforts and may be executed on-line (e.g. in the electric vehicle Battery Management System). The Electrothermal Impedance Spectroscopy (ETIS) can be used as a relatively simple and fast method for non-destructive parametrization of the battery thermal models. However, the ETIS requires expensive galvanostat with high-bandwidth and high-current capability for large format battery cells. Thus, this paper evaluates the possibility and accuracy of performing ETIS measurements with a standard battery test station (or bidirectional power supply) with low-bandwidth.