Overview
I designed a 42V lithium-ion battery management system from scratch for a large custom battery pack, engineering protection circuitry to keep it from going into thermal runaway. I took an MIT power electronics course partway through so I could properly handle the high-current, high-power-density circuitry, and after a few revisions I landed on a design that works, is cheap to manufacture, and has a small footprint.
Technical materials
What I learned
- Designed a 42V lithium-ion battery management system from scratch, engineering protection circuitry to prevent thermal runaway in a large custom battery pack
- Implemented over-current protection via shunt-resistor/op-amp current sensing and microcontroller-driven power-MOSFET cutoff, plus over-temperature and over/under-voltage monitoring
- Took an MIT power electronics course mid-project to properly design high-current, high-power-density circuitry
- Moved up to 4-layer PCB design and schematic capture in Fusion 360 - accounting for internal-layer copper thickness and trace sizing for thermal dissipation - manufactured through JLCPCB
Project related blog posts
- Preventing Your Batteries From Exploding
- Stepping Into the World of 4-Layer PCB Design
- Battery Safety in Practice: BMS Revision A