Batteries are so ubiquitous, that it is easy to forget they how dangerous they can be when not in the right conditions. I was reminded of this brutal fact during my summer research at the ESE lab that summer of 2025 when I managed to burn my fingertips through my latex gloves by shorting a commercial cell.
That was quite a random story. well, I only brought it up to emphasize one thing - the importance of properly controlling battery cells when they are put in practice, through battery management systems. And underneath it's magic, lies equivalent circuit models - models that attempted in reducing coupled, complex battery characteristics into terms manipulable by computer algorithms. Protecting our devices, and more importantly, us (my fingertips included). Anyways, here's a brief snippet of what I looked into while delving into the deep ends of ECMs: