So-called smart batteries are something that can be seen with increasing frequency, also called Info batteries (in connection with cameras , for example) or intelligent batteries. Is not really tied to any particular chemical system has long been used in for example certain laptop and video batteries and in several other contexts. The so-called Smart circuit functions as time counter / power gauge on the battery.
A circuit board with microcontroller, etc. (BMS Battery Management System, SBS, the Smart Battery System) is built into the battery and accurately measures in- and discharged energy, temperature, number of cycles and others parameters.
The result is presented in the attached equipment display or monitor, and you can always see for example remaining capacity in percent or operating time in hours / minutes, in comparison with the earlier simple battery meter in the form of a few LEDs, bars in a small LCD display or the like, which pretty roughly showed the battery’s status. The information between the battery and external equipment can take different forms of a physical data bus, regular standard SM-bus, I2C bus, CAN bus and so on.
On larger battery systems, like for example electric vehicles or similar one often has many parts and modules, instruments, displays, motor control, etc. charging circuits , etc., that share data from the battery’s common communication bus. Components of batteries and cells can be split between master and slave modules , different manufacturers can use a little different names for the parts, BMS, BMU and so on.