What is a battery management system?

1. What is battery management system? What does a battery management system consist of?
2. Functions of smart battery management system
3. What are the types of battery management system?
   1. Centralized BMS
   2. Decentralized BMS
4. Matching a battery to BMS
5. What is the best battery management system?
6. What is battery management system protection?
7. Does BMS prevent overcharging?
8. Do all lithium batteries need BMS?
9. How Do we charge a lithium battery without bms? Does a lithium battery with bms need a special charger?
10. Choosing the right BMS
11. BMS maintenance techniques
12. Is BMS available only for lithium batteries? What are lithium battery BMS characteristics?
13. What are the differences in lithium batteries’ BMS produced by different manufacturers?
14. Conclusion

Lithium batteries are common thanks to their low discharge, lightweight, long cycle life and fast charging features. Moreover, they have a long lifespan. How long can a lithium battery last? You can check the article of lithium ion battery cycle life to know the answer. Although lithium ions provide excellent performance, lithium is very active, and lithium batteries are more likely to overheat and short circuit in the case of overcharging and discharging.

While fixing this problem, a battery management system does the job. It prevents the battery from overcharging or undercharging. Additionally, It ensures the safety of lithium-ion batteries and, to some extent, makes up for the fact that lithium is too active.

1. What is battery management system? What does a battery management system consist of?

BMS is responsible for monitoring the operating status of each battery cell in the battery energy storage battery pack to ensure the safe and reliable operation of the energy storage module. The BMS contains the following components;

• Battery monitor- This checks a battery’s voltage. It is high-speed and measures high voltages at a low cost.
• Real-time clock
• Battery management system algorithms- This component helps the battery management system make effective real-time decisions.
• Battery voltage balance- A battery’s pack health is important for optimal performance. This component checks the batteryvoltage to ensure cells are in good condition.
• Cutoffs FETs- FET driver is responsible for connecting and disconnecting a battery pack’s load and the charger.

2. Functions of smart battery management system

BMS performs the following roles;

• Checking a battery’s state
• Determining the available energy in a battery
• Preventing the battery from operating beyond its safe area
• Balancing the voltage and current of the battery.
• Regulating charging rates and discharging rates of rechargeable batteries
• Examining battery temperature.
• Shutting down a battery after detecting hazardous conditions promotes safety when the battery operates.

3. What are the types of battery management system?

There are two main types of battery management system, which includes centralized BMS and decentralized BMS.

1. Centralized BMS

In this BMS, many operations are combined to form a module. The single module then connects to a battery using wires. The information interaction between the acquisition module and the main control module is directly realized on the circuit board.

Benefits:

1. It reduces the overall cost since it is only one integrated circuit is used
2. Accuracy is high since a similar offset is used in all cells

Disadvantages:

1. Long cables increase the chances of short-circuiting
2. Increasing chance of signal interference
3. It is difficult to scale up
4. Flexibility is limited

2. Decentralized BMS

A single control unit is used in a battery using a communication cable. As voltage requirement rises, complexities in control and communication also rise. Each BMS unit operated independently.
Benefits:

1. It is easy to integrate BMS units
2. It is scalable since a battery can be added and eliminated from the system without affecting other batteries.
3. This battery management system is safer.
4. It is more reliable since even if a single battery fails, the entire system continues since each battery is managed independently.

4. Matching a battery to BMS

While matching a battery to BMS, ensure that the BMS is compatible with the battery type, its voltage, current, temperature range, and capacity. As a result, the battery is safeguarded and begins to function at its best.

5. What is the best battery management system?

When determining a perfect BMS, it is vital for one to consider battery type, protection degree one desires their battery to have, and battery size. We need to choose a BMS that can match the voltage, current and capacity of the battery, so that the BMS can better play its protection function and will not damage the circuit.And we also need to take into account the battery application scenarios and environmental temperature.

6. What is battery management system protection?

BMS protection is a specific function of BMS, which is also the original intention of manufacturers to produce BMS. It plays a vital role in protecting battery lifespan and preventing battery damage from overcharging or undercharging.

7. Does BMS prevent overcharging

Yes, the BMS deal with the issue of overcharging in batteries. Most batteries tend to be damaged or have a reduced lifespan when not charged properly. The charger used by the lithium battery charger is divided into two stages, the first stage is called constant current (CC), during which the charger outputs a constant current to charge the battery.

When the battery is nearly full, the second stage is called the constant voltage (CV) phase, during which a constant voltage is supplied to the battery at a very low current. The BMS should ensure that the voltage and current during charging do not exceed the permeable limits to avoid overcharging or rapid charging of the battery. As a result, the BMS safeguards the battery from overcharging.

8. Do all lithium batteries need BMS?

Yes, there will be BMS in the lithium battery produced by every regular manufacturers, and BMS is an important part of the lithium battery. When a Li-ion battery is fully charged, the steady rise in lithium-ion battery voltage can cause overcharging, which is detrimental to battery health. At this time, the BMS is required to play the role of the control and protection circuit. That’s why we don’t need to worry too much about the safety of lithium batteries.

9. How Do we charge a lithium battery without bms? Does a lithium battery with bms need a special charger?

While charging a lithium battery without BMS, a wire is used in the battery connector to balance the battery’s charge.

Steps:

1. Acquire two wires. One of the wires will be used in the positive terminal while the other on the negative terminal. The two will be used as charging and discharging connections.
2. Wire the balance connector.
3. Connect the balance connector to the charger.
4. Check the details indicated in the manual so that one can use the battery’s appropriate balancing program. Match the battery’s chemistry with charge voltage
5. Begin charging.

However, as we mentioned earlier, BMS can guarantee the safety of lithium-ion batteries and extend their life, so it is not recommended to buy lithium-ion batteries without BMS. And generally speaking, lithium-ion batteries without BMS are not qualified products produced by regular manufacturers.
A lithium ion battery always needs a dedicated charger no matter there is a BMS or not.

10. Choosing the right BMS

While choosing a battery management system for your custom battery products, consider the following factors;

• Compatibility-Ensure that BMS is compatible with the battery
• Size of BMS- Larger BMS handle many batteries while small ones handle fewer batteries. But we also need to pay attention to the degree of adaptation with the battery pack packaging
• Level of protection- Different BMS offer different levels of protection.
• Topology- The battery management system varies in topology.
• Voltage- There exists a low voltage battery management system and a high voltage.
• Capacity- BMS capacity should match the battery’s capacity.
• Smart features- Consider the battery working environment and the actual application needs, to choose such as bluetooth, display, GPS, heating, cooling and other functions.

11. BMS maintenance techniques

For better maintenance of a BMS;

• Clean up the BMS regularly
• Check BMS frequently to ensure it performs and offers its services perfectly
• Update BMS software regularly to fix the working problem.

12. Is BMS available only for lithium batteries? What are lithium battery BMS characteristics?

No, the BMS is not used in lithium batteries alone. It can work in other batteries, including nickel-cadmium.
Lithium battery BMS contains the following features;

• Monitoring lithium battery health
• Temperature monitoring
• Overcharging protection
• Undercharging protection

13. What are the differences in lithium batteries’ BMS produced by different manufacturers?

Lithium batteries BMS from different manufacturers are different in the following ways;

• Safety protection- Different lithium batteries BMS provide different levels of protection to batteries.
• Specific cell parameters that a given BMS is responsible for measuring
• BMS battery cell balancing
• BMS voltage
• BMS capacity

14. Conclusion

The battery management system is essential in lithium batteries. BMS prevents not only overheating but also overcharging. Moreover, BMS protects a lithium battery from undercharging. It also monitors the battery’s temperature. Therefore, a suitable BMS can be selected according to the actual lithium ion battery applications.

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