How to improve the reliability of energy storage battery management system?

BMS are an integral part of lithium battery energy storage

Battery management system is a kind of electronic equipment that can manage and monitor the energy storage lithium battery. By collecting and calculating the voltage, current, temperature and SOC parameters, it can control the charging and discharging process of the battery and realize the protection of the battery. Lithium battery, improve the comprehensive performance of lithium battery.

With the rapid development of energy storage batteries, large arrays can be used as backup and continuously powered energy storage systems, which are increasingly valued in Germany and Australia, as evidenced by the doubling of the number of household battery installations each year. The home energy storage battery system is continuously charged by the grid or other community energy, and then provides alternating current (AC) to the user through a DC/AC inverter.

The use of lithium batteries as backup power is not new, there are a variety of battery backup power systems, such as basic 120/240V AC and hundreds of watts of power for desktop, Marine, hybrid vehicles short-term backup power system or pure electric vehicles using a few kilowatts of special vehicle backup power system, Telecommunications systems and data centers use grid-scale backup power systems of hundreds of kilowatts... Etc. While advances in lithium battery chemistry and lithium battery technology have attracted a lot of attention, there is an equally important component to viable battery-based backup systems: battery management systems (BMS).

Battery management system is a kind of electronic equipment that can manage and monitor the energy storage lithium battery. By collecting and calculating the voltage, current, temperature, SOC and other parameters, it can control the charging and discharging process of the battery, so as to protect the lithium battery and improve the comprehensive performance of the lithium battery.

Lithium ion battery backup power supply is suitable for fixed and mobile use of several kilowatts to several hundred kilowatts of power, providing a reliable and efficient power supply for a variety of applications.

There are many challenges to completing a battery management system for energy storage battery use, and the solution is not simply to "scale out" the management system from a small, low-capacity lithium battery pack. Instead, new, more complex policies and key supporting components are needed.

The starting point of the challenge is that many important lithium battery parameters need to be measured with a high degree of accuracy and confidence. In addition, the subsystem planning must be modular, able to be customized to the specific requirements of the configuration, considering possible scaling requirements, overall management issues, and necessary maintenance.

The operating environment of large battery storage systems also presents other significant challenges. BMS must also be exposed to very noisy electrical environments, often at very high temperatures, to provide accurate, generic data, with high inverter voltage/current and therefore current spikes. In addition, BMS must provide a wide range of "fine" data for internal module and system temperature measurements, rather than a limited amount of roughly aggregated data, which is essential for charging, monitoring, and discharging.

Because of the important role of these power systems, their operational reliability is essentially critical. In order for the above clear and simple goals to become a reality, BMS must ensure the accuracy and completeness of data and continuous health assessment so that BMS can continue to take the required actions. To achieve reliable planning and reliable safety is a multi-layered process, the BMS must anticipate possible problems with all subsystems, perform self-checks and power failure detection, and then select the appropriate action in standby and working mode. The last requirement is that BMS must meet many strict regulatory standards due to high voltage, high current and high power.

BMS programming translates concepts into practical results

While supervising rechargeable batteries is conceptually simple, requiring only voltage and current measuring circuits to be placed at the battery terminals, the reality of BMS is quite different and much more complex.

Robust planning begins with the overall regulation of each cell segment and makes some important requirements for the function of analog circuits. The BMS must evaluate the validity of each measurement, as it is required to maximize data integrity, and the BMS must also identify erroneous or problematic readings. The BMS cannot ignore abnormal readings, as such readings may indicate the presence of potential

Why do we need BMS for lithium-ion battery storage?

Safety requirements:

The disadvantage of lithium-ion battery storage is that it is "delicate" and a single overdischarge may cause permanent damage to the battery. In extreme cases, lithium batteries can overheat or overcharge, leading to thermal runaway, battery rupture or even explosion. Therefore, lithium batteries need BMS to strictly control the charging and discharging process to avoid overcharging and overdischarging and overheating.

Functional requirements:

Energy storage lithium batteries need to know the SOC parameters of lithium batteries during use to predict the remaining battery capacity. BMS can measure lithium battery SOC in real time to meet customer application requirements.

BMS can improve the overall performance of lithium batteries by changing the inconsistencies of batteries evenly.

Lithium ion batteries will have different performance at different temperatures, the best operating temperature of lithium ion is 25-40℃. Changes in temperature can change the SOC, open circuit voltage, internal resistance, and available power of the battery, and even affect the battery life. BMS can control the operating temperature of the battery and improve the battery characteristics.

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