BMS Battery Management System Detailed Features

In the previous article, we detailed the reasons lithium batteries need a BMS battery management system, so what is a BMS? The battery management system, which is the core of a lithium battery and can monitor the battery’s data and report basic battery parameters and fault information.

The two mainstream protection methods for lithium batteries are BMS and protection boards. The protection board is a PCB with several integrated protection functions and is characterised because it can work without electrical components, such as relays, DCDCs and shunts. This saves space inside the battery and the cost is low. Most of the household energy storage uses protection boards. The BMS uses more electrical components than the protection board and the total cost and space requirements inside the battery are higher. However, the BMS has secondary protection and is more reliable in terms of safety. In addition, the BMS can implement many complex functions that protection boards can not achieve. In today’s article, we inspect the BMS.

Structural composition of the BMS battery management system

The BMS not only ensures that the battery works in a safe condition but also ensures the accuracy of the returned data and responds to abnormalities in a timely manner. The BMS uses functions such as voltage, current and temperature monitoring to protect, troubleshoot and alarm the battery, and operates with other controller functions to ensure the safe use of the battery. Battery management systems have a wealth of hardware and software systems, which include high voltage boxes, master control boxes, slave control boxes, auxiliary components, relay integrators, and so on. So what is the structure of a BMS as a device that provides functional protection and warning for the battery? What are the minimum functions required for a qualified BMS?

Introduction to the major functions of the BMS battery management system

The BMS consists of four components: the battery management system, the voltage balance control system, the thermal management system and the safety protection system. Each of the four components has its own role to play in order to give the battery the best protection.

▊ Battery management systems

Battery management systems are used to protect the battery system, estimate the battery state and diagnose faults online through functions such as voltage detection. The estimation of the battery state revolves around two main areas: SOC and SOH.

▊ Voltage balancing control systems

The voltage balancing control system is through items such as charging control, automatic equalisation, relay control, SOC estimation, charge and discharge management, equalisation control, fault alarm and handling lights. The voltage balancing control system is used to achieve voltage balancing control by communicating with other controllers, etc.

▊ Thermal management systems

The main purpose of the thermal management system is to ensure that the battery pack operates in a suitable working environment. Of course, this is not just a heating function, as the thermal management system monitors the battery temperature and dissipates heat effectively when the battery temperature is too high. The thermal management system monitors the battery temperature and dissipates heat effectively when the battery temperature is too high, and heats the battery quickly at low temperatures. At the same time, it ensures that the battery pack is effectively ventilated when harmful gases are generated. This ensures the stability of the battery pack’s performance.

▊ Safety and security systems

Safety protection is the most important function of the entire BMS. Without it, all the previously mentioned protection functions would be empty talk. With regard to the battery protection functions, we can roughly group them into the following four sections:

Over-current protection: Batteries have a certain internal resistance. If the working current of the battery is too high, a certain amount of heat will be generated inside the battery, making the temperature of the battery rise and the thermal stability decrease.

Overcharge and over-discharge protection: The dangers of overcharging and over-discharging the battery pack have been described in detail in our previous articles. Long-term overcharging can lead to a reduction in battery capacity, high voltage, or even a short circuit of the positive and negative terminals, resulting in an explosion. The BMS will determine whether the individual cell voltage has exceeded the charge/discharge limit and will immediately disconnect the charge/discharge circuit once the limit has been exceeded.

Over-temperature protection: Stable battery operation requires the right temperature. Over-temperature protection incorporates a thermal management system where the BMS disables the system from charging and discharging when the battery temperature is too high or too low.

Insulation monitoring: Small energy storage batteries have a minimum of 12V, while high voltage batteries can reach hundreds of volts, which can pose an enormous threat to the safety of the user in the event of a battery leakage. The BMS monitors the insulation values of the battery and the total negative piggyback in real time, and once these values fall below the safe range, the BMS will immediately report the data and cut off the power.

Summary

With today’s introduction, we believe you have a comprehensive understanding of the BMS battery management system. If you would like to know more about the features of the BMS, you can refer to our article: Battery Management Systems: Everything You Want to Know. If you would like to know more about the product details, please leave us a message!