Rechargeable batteries found in electronic devices, autos, and anywhere else, usually require a battery management system, or BMS, which is a small circuit that is incorporated into the battery.
Given the sensitivity of some secondary batteries, like Li-ion, to incorrect charging or discharging practices, the need for a BMS becomes clear as they can be critical when it comes to safety.
A BMS is chiefly used to monitor and control the criteria which affect battery life and safe function. Every rechargeable battery has conditions that must be maintained in order to operate safely, such as a certain voltage, current, and remaining at a safe temperature.
Operating outside of these conditions could lead to problems such as over or under voltage that may negatively affect the batteries lifespan, cause the battery to stop working correctly, or, in extreme cases, cause dangers such as overheating and fires:
What does the BMS measure?
This can vary, but the BMS and its software will be measuring battery performance in order to avoid it entering dangerous operating conditions.
They may measure:
- Battery State Of Charge (SOC) – controls safe charging and discharging of the battery to avoid overcharging or discharging, the latter being very harmful to Li-ion batteries.
- Battery temperature – some BMS will monitor battery temperature and if it reaches a certain prohibited level can activate a thermal management system in order to cool it.
- Battery State Of Health (SOH) – charge/discharge cycling can help calculate this to show wear and tear in the battery and reduced total capacity.
- Current coming into or flowing from the battery.
- Battery State Of Safety (SOS)
If the battery is found to be operating outside of normal conditions, what can the BMS do?
The BMS can activate cooling measures, switch off the battery, or reduce or stop the device’s power use.
