Question: If I have 48 lithium cells connected in series as a pack, how would I best go about physically implementing a system to measure, isolate, and relay cell voltages to a centrally managed microcontroller? I am currently considering the usage of analog optoisolators, but I would be grateful for any advice. However, I would need the ICs and other parts to be hand solderable (ie DIP) as these are the only tools I have available. Thank you!
Context: I am part of a high school electric vehicle team, where we design, build, and test fully electric vehicles converted from gas cars. I joined the team with lots of heavy work already done, but we need a management system for our newly installed LiFePO batteries. Our instructor is considering purchasing a better commercial grade BMS (ironically enough our current one is only consistent in failing), but would rather have our team design a BMS, however rudimentary.
I am looking to design a BMS for a 48 cell LiFePO battery pack. This system would comprise cell voltage readouts and basic cell overvoltage drain functions. I plan on using probes for each individual cell and centrally managing them via some form of microcontroller. In addition to needing to multiplex the data, isolation of the cells and interfacing to a monitor are my major concerns. Because isolation is a major challenge and poses significant safety and reliability implications, I decided to start there.