MEB Batteries
Volkswagen have specified a standard module that always has the same dimensions (590x225x110mm) and comes in 3P8S (82 kWh batteries) and 2P12S (48, 55, and 62 kWh) flavours. Each module has an energy content of 6.85 kWh.
Forum thread: https://openinverter.org/forum/viewtopic.php?t=1948
It comes along with 4 relays where 2 make the connection to the drive train and the other 2 make the connection to the quick charge port. It uses a varying number of module units that measure voltage and module temperature and execute balancing commands with about 100 mA of balancing current. The CAN protocol of these modules has been reverse engineered by Tom de Bree and a compact high level implementation was done by Johannes.
There is also a HV controller that performs the high level BMS calculations, controls the contactors and various other tasks but its protocol has not been reverse engineered.