What is BMS (Battery Management System)?
The BMS, a battery management system, is an electronic circuit unit that protects the battery against unfavourable conditions. This component, consisting mainly of electronic elements, precisely monitors the charge, voltage and discharge circuit current of the cells at temperatures between -40°C and +85°C and controls the timely opening and closing of the current circuit according to the need or emergency situations.
An ordinary lithium battery protection circuit generally includes the control board, resistors, capacitors, Mos switches and some additional auxiliary devices. Here, the control circuit controls the cell and the Mos switch under normal conditions to ensure the execution of the external circuit. When the cell voltage or loop current exceeds the specified values, it takes the situation under control by switching off the Mos switch to prevent possible damage to the battery pack and protect its safety.
What are the Basic Parts of the BMS Circuit?
Basically, BMS’s have 6 components. These components can be listed as follows:
- Cutting Process (FET – Field Effect Transsistor)
- Cell Voltage Balance
- BMS Algorithms
- Real Time Clock (RTC)
- Temperature Monitoring
- Battery Cell Monitor
Let us clarify the importance of each component of the battery management system (BMS) and how it is implemented:
Battery Cell Observation and Inspection
The Battery Management System (BMS) primarily monitors voltages for battery systems. It consists of a high-speed system infrastructure that provides a very low cost for high voltage measurements. Its advantages can be listed as follows:
- It monitors the individual cell voltage according to the adjustable voltage level. This is one of the easiest ways to determine the charge of the battery pack.
- The charging mechanism switches on automatically when the voltage of the first cell reaches the set voltage limit. It is also indicated when the battery reaches the charge limit.
- If the battery pack has an average less charge rate than the cell, the least charged cell reaches the limit and the rest of the cells are left partially charged.
Interrupt Switching
The FET driver is a driver responsible for the connection and isolation between the charge of the battery pack and the charger. Voltage, current measurements, behaviour prediction and real-time sensing are done through the circuit. Its advantages are:
- The battery can be connected to the high or low side of the battery pack.
- Activation of NMOS FETs is required to enable the high-side connection of the battery and a charge driver is also required.
- Since a charging source is not needed, a low-side FET driver is often used in integrated solutions to reduce costs.
Temperature Monitoring
As users’ expectations on the product increase, the battery packs are in constant fluctuation as they supply current at a constant voltage. The continuous operation of batteries can cause destructive or flammable events such as fire or explosion. The battery protection circuit (BMS) analyses these processes and provides the following advantages in these situations:
- Using temperature measurement we can recognise whether the battery needs to be charged or discharged.
- The great advantage of temperature sensors is that they can measure and monitor energy storage systems or battery cell groups.
- The circuit temperature is monitored by the thermistor, which is powered by internal voltage. Using the internal voltage reference helps reduce temperature inaccuracies and improves the overall measurement system.
Cell Voltage Balance
Determining the health of the battery pack is very important. Therefore, in order to achieve a long battery life, it must be ensured that the cells are operating under appropriate operating conditions. For this, cell voltage monitoring is performed.
- The operating voltage range of lithium ion batteries varies between 2.5v and 4.2v.
- Battery life is highly affected in operations outside the voltage range of the battery. These situations reduce the life of the battery.
- If the battery pack is connected in parallel, the overall drive current increases, and if it is connected in series, the overall voltage increases.
BMS Algorithm
The BMS needs a microcontroller to make fast and effective decisions in real time according to the information received through the battery pack, to organise, collect and evaluate the information from the sensing circuit for this purpose.
The memory space for the battery protection circuit clock cycles can be cleared using some external standalone solutions.
Real Time Clock
The real-time clock acts as a black box, allowing users to know the behaviour of the battery pack before an adverse event occurs.
- The BMS electronics are protected from synchronisation with the 3rd party battery pack by the battery verification event.
- The peripheral power circuit is utilised in line with the components of the battery management system via the voltage reference/regulator.
For more details and price information about BMS products, you can review our website in detail or contact our expert team at the contact address. You can also see detailed information about battery production at HDA Power.
Frequently Asked Questions About BMS
What are the advantages of using BMS?
Using BMS, you can extend the life, ensure the safety and improve the energy efficiency of rechargeable battery systems.
How does BMS extend the life of batteries?
Thanks to BMS, it extends the life of your battery by controlling overcharge, discharge and overheating conditions.
Which types of rechargeable batteries can the BMS be used for?
BMS can be used in many battery systems, some of them: Lithium-ion, lead-acid, Lithium Iron Phosphate, Nickel-Cadmium, etc.