Do lithium ion batteries need a BMS system?

Lithium-ion batteries, especially custom lithium ion battery packs, need a BMS (Battery Management System) to ensure the battery is reliable and safe. The battery management system is the brain of the lithium battery and reports the status and health of the battery. Let’s get a better understanding from this article. What is a BMS System?

What is a battery balancing system (BMS)?

The BMS is an important part of maintaining the normal operation of the battery system, with special attention to balancing the battery BMS voltage to ensure the stability and life of the battery pack. The voltage of the BMS ranges from tens of volts to hundreds of volts. The higher the voltage, the greater the power.

What does a battery management system (BMS) do?

In general, a BMS performs these functions: Cell balancing: The individual battery pack cells need to be monitored and balanced to redistribute charge between cells during charging and discharging cycles.

How does a BMS monitor a battery pack?

Detection of imbalance: The BMS continuously monitors the voltage of each cell or module in the battery pack. When the voltage of some cells is significantly higher than that of others, or the voltage difference exceeds a preset threshold, the BMS determines that the battery pack is unbalanced.

How can a BMS achieve voltage balance in a battery pack?

Here are the general steps of how a BMS can achieve voltage balance in a battery pack: Detection of imbalance: The BMS continuously monitors the voltage of each cell or module in the battery pack.

How does a BMS charge a lithium ion battery?

As cells approach their maximum voltage (typically 4.2V for lithium-ion), the BMS gradually reduces charging current following a constant-current/constant-voltage (CC/CV) profile. The charging cutoff occurs when both voltage and current criteria are met – usually when current drops below C/20 (5A for a 100Ah battery) while at maximum voltage.