Butterworth initial energy storage

What is the cutoff frequency of the Butterworth low-pass filter?

The cutoff frequency of the Butterworth low-pass filter can be designed based on the cutoff frequency of the battery system . However, the corner frequency of the battery system is unknown in most cases and can be falsely determined due to the presence of measurement noises, especially for complicated energy storage systems.

Why does Butterworth low-pass filter adapt based on a lithium-ion battery?

This equation explains that the cutoff frequency is closely related to the time constant of the lithium-ion battery; therefore, following this equation, the cut-off frequency of the Butterworth low-pass filter adapts based on the identified time constant of the lithium-ion battery.

How does a Butterworth low-pass filter improve parameter identification accuracy?

The proposed algorithm adapts the cutoff frequency of the Butterworth low-pass filter along with the lithium-ion battery operations thus ensures parameter identification accuracy in various operating conditions.