Battery model for overdischarge

Hello everyone,

i want to create a model to simulate a battery's behaviour when it is overdischaged. Has anyone a suggetsion on how to do it without using the table based battery model and hard writing a discharge curve that goes from 4.2V to 0V?

Answer 1

[Gautam]

Hello Tiago,

I understand that you want to model the behaviour of an overdischarged battery. You can represent the battery using equivalent electrical components that capture its key characteristics

You can follow the steps below to model the battery in SIMULINK

1. Voltage Source for OCV: OCV can be modeled as a voltage source whose value depends on the State of Charge (SoC) of the battery. The relationship between SoC and OCV can be represented by a mathematical function or a simple piecewise linear approximation that represents the OCV as a function of SoC.
2. Implement SoC Dynamics: SoC dynamics can be implemented using an Integrator block. You might need to adjust the sign based on whether the battery is charging or discharging.
3. Internal Resistance: Internal Resistance can be modelled using a resistor in series with the voltage source.
4. Current Measurement: Use a Current Measurement block to measure the current flowing into or out of the battery, which will be fed into the SoC calculation.
5. Overdischarge: To simulate overdischarge, your OCV-SoC function should reflect the rapid voltage drop that occurs as the battery discharges below a certain threshold. You might need to implement additional logic to model the effects of overdischarge on the battery's internal resistance and capacity.

Following steps like these, you can simulate overdischarge behavior without the need for hardcoded discharge curves or table-based models

Thank you,

Gautam Murthy