Found a great paper that covers lots of techniques for balancing series-connected cells in a battery-pack. IREE - A Review of Passive and Active Battery Balancing based on MATLAB/Simulink It covers technical highlights of several different methods of cell balancing, then compares them on time-to-balance, complexity, size, and cost. Granting the fact that I'm a nerd, I thought it was both good and informative. One thing that is not covered is a failure-mode analysis, i.e. effects from one part of the balancing circuitry failing. Does make me curious what specific flavor of balancing is in use in the Tesla pack/BMS.