Battery Management System

Batteries are the heart of an Electric Vehicle but the Battery Management System is more like the brain which keeps the Heart pumping out electricity to the Motor safely and at required output. Electric Vehicles use Li Ion Type batteries which have a high energy density between 100-265 Wh/kg. There are many safety risks like Thermal runway of batteries in Electric Vehicles. Thus for the safety of the Driver and occupants of EV it is necessary the Batteries or Battery Pack operate inside safety limits.

What Is Battery Management System?

Battery Management System or BMS for short primary objective is to Protect the User and the Battery by making sure the Battery operates safely inside the Operating Parameters defined by the Manufacturer (State of Safety-SoS).

What else does the BMS do?

  1. Keep an Eye on Various Battery Parameters.
    • Monitors the State of Charge (SoC) of the Battery pack, LIB perform best when maintained between the max and min Charge limits or Usable SoC window.
    • Monitors the State of Health (SoH) of the Battery pack
    • State of Power (SoP) which shows amount of power available.
    • Safe Operation of the Battery during Charging and Discharging by Monitoring:
      • The Temperature
      • Voltage across the battery
      • Input and output Current.
      • Speed and Flow of Coolant
    • Safe HV operation by monitoring HV system and controlling closing and opening contactors:
      • checking HV isolation
      • handshake with vehicle to ensure electrical system is ok before closing contactors
      • opening contactors as final safety barrier to avoid damage
      • opening contactors on crash signal
  2. It Does Some Math’s and calculations:
    • Optimizes the life of Battery by Balancing the different Cells in the batteries.
    • Monitor the Charging Cycles.
    • Spent Energy in kWh
    • Charge in Ampere per hour (Ah) known as the Coulomb Counter to find the cells Efficiency.
  3. Thermal Management:
    • The Temperature monitoring through various sensors
    • Speed and Flow of Coolant based on above to Maintain the Temperature.
    • In Winter or low temperatures communicating and implementing Internal or External Heating Strategies.
  4. Communication with Internal through CAN Bus and External Devices
    • External
      • On-Board Charger
      • Charging Station
      • To the driver through Dashboard info like Range, State of Charge.
      • Motor Controller
    • Internal Communication between Master BMS and Slave BMS. In Turn Slave BMS communicate with Batteries on modular level depending on the Battery Cell Pack Architecture.

Battery Management System is a rapidly growing Market as Electric Vehicles Adoption increases across the Globe. Below you can see Market Growth rate 15% from 2021 – 2030 with a Market size of 22M$ in 2030.

5 thoughts on “Battery Management System”

  1. Hi. Thanks for your nice website related to BMS.
    There is a question in my mind about BMS topology.
    Assume we have 4 packs and in each pack we have 5 modules and in each module we have 10 cells.
    What type of topology is suitable for this application?
    How many slave-BMS and Master-BMS do we need?


Leave a Comment

The reCAPTCHA verification period has expired. Please reload the page.