A BMS may monitor the state of the battery as represented by various items, such as: The BMS will also control the recharging of the battery by redirecting the recovered energy (i.e., from regenerative braking) back into the battery pack (typically composed of a number of battery modules, each composed of a number of cells).
The BMS also monitors the remaining capacity in the battery. It continuously tracks the energy going in and out of the battery pack and monitors the battery voltage. It uses this data to know when the battery is depleted and turn it off. That’s why lithium-ion batteries don’t show signs of dying like lead acid, but just shut down.
Protection circuit module (PCM) is a simpler alternative to BMS. A battery pack built together with a battery management system with an external communication data bus is a smart battery pack. A smart battery pack must be charged by a smart battery charger.
Figure 1. A Simplified Diagram of the Building Blocks of a Battery Management System A battery management system can be comprised of many functional blocks including: cutoff FETs, a fuel gauge monitor, cell voltage monitor, cell voltage balance, real time clock (RTC), temperature monitors and a state machine.
Hence no current flows through the BMS. And till the time the battery is not recharged and the voltage of the cell does not cross beyond the V ODR (Over-discharge release voltage), the BMS doesn’t allow the usage of the battery pack, thus increasing the life of our battery pack.
In case of the battery packs, it helps in maintaining equal charging and discharging of the cells. This massively improves the performance of the battery pack. Not only performance but an efficient Battery Management System is useful in improving the life of the battery packs.