Last modified: Jan 20, 2024

Battery management

A Battery Management System (BMS) is a critical component in an Electric Vehicle (EV) that is responsible for managing the performance, health, and safety of the battery.

The BMS is a sophisticated electronic system that monitors and controls the charging and discharging of the battery, as well as its temperature, state of charge (SOC), and state of health (SOH).

The BMS consists of the battery management controller (BMC) and cell module controllers (CMCs). The CMCs are integrated directly into the modules of the high-voltage battery and supply the BMC with measured values such as cell voltage and temperature.

In an EV, the BMS plays a crucial role in ensuring the optimal performance and longevity of the battery. The BMS provides the following functions:

Cell monitoring: The BMS monitors the voltage, temperature, and SOC of each individual cell in the battery pack. This allows it to identify any cell that is operating outside of the normal range, and take corrective action to prevent damage or degradation. They are also responsible for cell balancing.

Charging control: The BMS controls the charging process of the battery, ensuring that it is charged safely and efficiently. It regulates the charging current, voltage, and temperature to prevent overcharging, overheating, and other conditions that can damage the battery.

Discharging control: The BMS also controls the discharging of the battery, ensuring that the battery is used in a safe and efficient manner. It regulates the output voltage and current, and ensures that the battery is not discharged beyond its safe limits. As an example. It is the BMS that limits the power on many EVs in cold weather to protect the battery.

Thermal management: The BMS monitors the temperature of the battery and manages the cooling and heating systems to maintain the optimal temperature range for the battery. This helps to prevent overheating, which can cause damage to the battery, and maintain the battery’s performance and longevity.

State of Health (SOH) monitoring: The BMS monitors the SOH of the battery by analyzing its performance and degradation over time. It provides warnings and alerts when the battery’s health is compromised, and recommends maintenance or replacement when necessary.

Battery management electronics for Audi e-tron battery pack

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