BMS battery management system principle

The battery management system (BMS) can quickly and reliably monitor the state of charge (SoC), state of health (SoH) and state of function (SoF) based on starting capability to provide necessary information. Therefore, BMS can minimize the number of vehicle failures caused by unexpected battery failure, thereby maximizing battery life and battery efficiency, and achieving CO2 emission reduction functions. The key component of BMS is the intelligent battery sensor (IBS), which can measure the terminal voltage, current and temperature of the battery and calculate the status of the battery.

battery management system

A typical power supply network used to power a start-stop system consists of a body control module (BCM), a battery management system (BMS), a generator and a DC/DC converter (see Figure 1).


The BMS provides battery status information to the BCM with the help of a dedicated load management algorithm, and the BCM stabilizes and manages the power supply network by controlling the generator and DC/DC converter. The DC/DC converter distributes electrical energy to various electrical components inside the car.

Typically, the BMS for lead-acid batteries is mounted directly into a smart connector on the battery clamp. The connector consists of a low-value shunt resistor (typically in the 100u range) and a small PCB with a highly integrated device with accurate measurement and processing capabilities called an Intelligent Battery Sensor (IBS, see Figure 2). IBS measures battery voltage, current and temperature with high resolution and accuracy even in the harshest conditions and throughout its lifetime to correctly predict the battery’s state of charge (SoC) state of health (SoH) and functionality Status(SOF). These parameters are transmitted to the BCM regularly or on request via an in-vehicle network certified by the automotive industry.

bms 3

In addition to the above-mentioned functions and parameter performance, other key requirements for IBS include low power consumption, the ability to work in harsh automotive environments (i.e., EMC, ESD), and in-vehicle communication interface conformance testing (i.e., LIN) for acceptance by automotive OEM manufacturers. ) meets the automotive grade test limits (6 limits for the measured parameters), and also meets the AEC-Q100 standard requirements.

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