Battery, Charge/Discharge, Time-Scheduled Profile, ANSYS Fluent CFD Simulation

Description

Description

In this CFD project, we present the numerical simulation of the battery charge/discharge cycles by time-scheduled profile via ANSYS Fluent software.

A battery is a device that converts chemical energy into electric energy through chemical reactions if needed. The main zone of a battery is the active cell, where electrochemical reactions occur. The passive zones include a battery’s positive and negative tabs (terminals) for electric conductivity.

Batteries are exposed to charge and discharge during operation. During charging, the electric current is supplied by an external source. However, during discharging, the electric current is consumed by an electric load.

Generally, batteries are simulated either in a charging or discharging state. However, in this project, we aim to simulate several sequential charging and discharging processes.

In this project, we analyzed a prismatic battery. Prismatic batteries are commonly used for applications with high powers, such as energy storage systems, electric vehicles, and industrial equipment.

Methodology

First, we modeled the battery geometry using Design Modeler software. The battery construction consists of a cell zone with positive and negative tab zones.

Then, we meshed the model using ANSYS Meshing software, and 55339 elements were generated.

Finally, we simulated the battery system using the Battery model in ANSYS Fluent software.

In this project, we used the Multi-Scale Multi-Domain (MSMD) model for battery modeling. The MSMD is a comprehensive method for modeling lithium-ion batteries; because it involves a multi-scale and multi-physic nature.

Then, we used the ECM (Equivalent Circuit Model) sub-model to specify the electrochemical computations. The ECM model is considered a semi-empirical method for electrochemical formulation.

Since we aim to simulate several sequential charging and discharging processes, we use a time-scheduled profile.

According to our defined profile, the battery discharged by a 20 A current in the first 300 s, charged by a 1 C-rate in the next 300 s, discharged by an 80 W power in the next 300 s, charged by a 10 A current in the next 300 s and finally discharged by a 0.5 C-rate in the last 300 s.

Since the charging/discharging process in the battery system occurs over time, we run the calculation in an unsteady state (transient).

Conclusion

We intend to analyze the battery behavior during the charging and discharging processes. Therefore, we provided the plot of potential (voltage) variations based on the time. Then, we obtained cell voltage contours at different times.

The plot and contours show that the battery undergoes several charge/discharge cycles at different rates in 300-second periods. So, we conclude that our time-scheduled profile has worked correctly.

In addition, we obtained the contours of the potential and temperature at different times at the 2 C rate. The results show a decrease in voltage and an increase in temperature during discharge.

In addition, we obtained contours of temperature, current magnitude, and SOC (state of charge) for our battery in the final state.