Electrical-Thermal Modelling and Analysis of Battery Energy System in Electric Vehicles

The development and implementation of Lithium-ion (Li-ion) batteries, particularly in Automotive applications, requires substantial diagnostic and practical modelling efforts to fully understand the electrical and thermal characteristics in the batteries across various operating conditions. Electrical thermal modelling prompts the understanding of the battery electrical characteristics along with the thermal behavior beyond what is possible from experiments, and it provides a basis for exploring electrical and thermal management control strategies for batteries in electric vehicles (EVs). For replicating the electrical behavior of Li-ion batteries under varied operating situations, an equivalent circuit model (ECM) must be created. This model aids in forecasting the transient distribution of electrical and thermal properties at various operating states as well as estimating heat generation within the battery pack.

The paper focus in the following application areas:

• An equivalent circuit model (ECM) will be developed to simulate the current-voltage characteristics of the battery during various discharging and drive profiles.
• The electro-thermal model will be developed and calibrated by a set of characterization tests collected over a wide range of temperature, voltage, and current data.
• Integration of cell to module and module to pack level through implementation along with other circuitry components like cell-cell/module-module busbars to study the voltage and temperature behavior at different scenarios.
• Implementation of current limits maps and control strategies to the battery pack model to optimize the battery performance with respect to electrical and thermal behavior.