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  • Writer's pictureSemco Infratech

Energy Storage BMS: The Secret Weapon for a Successful Battery System

Energy Storage BMS: The Secret Weapon for a Successful Battery System

The battery is an energy storage element, whether it is found in an electric car, an energy storage power plant, or a base station power supply. The battery's perception, decision-making process, and implementation make up the entire energy storage control system. The BMS is a crucial sensor that forms the backbone of the energy storage system.

The battery management system's (BMS) operating environment

High voltage: The battery's cluster voltage can frequently reach up to 700V.

  • High current: The current in a battery cluster can frequently reach 100 to 300 amps.

  • The deep discharge and charge depth (DOD) of deep circulation batteries is typically 80 percent or higher.

The operating environment characteristics of the energy storage system have special requirements for energy storage BMS:

1. For general energy storage systems, in a limited space, the energy storage capacity of the battery pack is often MWh, and the conversion power is hundreds of KW to MW, which requires a large number of batteries to be connected in series. An energy storage unit is often composed of multiple sets of battery clusters in parallel into battery arrays and involves the coordination of multiple control units, system topology, and complex system wiring. It makes the energy storage system characterized by high DC side voltage (up to more than 1500V), high power (hundreds of kilowatts or megawatts), a large number of batteries, harsh electromagnetic environment, serious interference, huge data, and complex control. Extremely high requirements are put forward for BMS circuit principle and layout wiring design, anti-interference EMC design, data processing ability, response speed, etc. At the same time, it also puts forward high requirements for the layout, wiring, grounding, and other design of the entire energy storage system. It is necessary to consider not only the safety of wiring but also the coupling and shielding of signals.

2. The consistency of cell capacity in the battery cluster at the end of charge and discharge will affect the available capacity of the energy storage system and lower its efficiency because of the features of deep charging and discharging of the energy storage system. Energy storage BMS must be required to have strong battery balance management ability in order to guarantee the consistency of monomer battery performance in the battery pack.

In order to quickly and effectively compensate for the differences caused by the primary charging and discharge cycle battery packs, eliminate the differences, and guarantee that the available capacity of the battery system is maximized, the energy storage system typically needs active balancing technology. The equilibrium current is typically between 0.5 and 5A.

3. Temperature control is crucial for ensuring the battery's service life, and the system's thermal management needs to be carefully planned. Due to the high charging and discharge current, energy storage systems, particularly those used in frequency modulation and peak regulation applications, will experience significant heating and uneven discharge of the battery, which will ultimately shorten the battery's service life.

The BMS thermal management control strategy, the system heat dissipation air duct, and the battery module's thermal design are all included in the thermal management design. Battery heat management can be more effectively achieved with the liquid cooling system. In a similar vein, abnormal battery temperature is frequently a sign of thermal runaway and a decline in battery performance, which makes battery temperature monitoring crucial. It is frequently required to monitor the battery temperature according to each cell's requirements in order to prevent blind spots in the battery abnormal temperature monitoring.

4.The parallel control strategy of the battery pack must also be taken into account when using multiple batteries in parallel, also known as battery stack maintenance, in order to prevent circulation brought on by the voltage differential between batteries and to ensure balanced maintenance between various battery clusters.

5. BMS control units must have complex and negotiated processing power and response speed, as well as set high requirements for processor, software architecture, and code quality because of the system's complexity, numerous data interfaces, and numerous data access points.

6. High reliability, system fault tolerance, and functional safety requirements for BMS are also necessary because the energy storage system has very high safety and reliability requirements.

Currently, the relevant standards for energy storage BMS do not specify the reliability index. The design life of an energy storage system is typically 15 years, and correspondingly, the life requirement for energy storage BMS is 15 years.

7. One of the main obstacles to the growth of the energy storage sector is the safety of energy storage systems. Early warning and battery safety status analysis are crucial BMS requirements. In conclusion, there are significant distinctions between automotive and energy storage BMSs.

The life cycle of the energy storage system is longer, it is larger and more complex, and the charging and discharging depths are deeper. As a result, in light of the aforementioned variations, energy storage BMS development and design must be done specifically.

In order to ensure the safe and dependable functioning of the energy storage system and to clarify the relationship between the three levels of the architecture—cell, battery cluster, and battery array—the corresponding BMS must also be managed for the battery array architecture.

The vital part of the energy storage system is the battery management system, or BMS. Its significance is obvious.

For the industry, battery energy storage system safety has emerged as a critical issue.

Although the BMS is currently keeping an eye on the battery's voltage and temperature, it still needs to find a solution for its accuracy and computation issues. To guarantee accurate and real-time data collection, the BMS anti-dry disturbance capability must be strengthened. This is especially important for accurately monitoring the monomer battery's temperature, which can effectively address the early warning issue of battery thermal runaway.

Assessment of the battery safety status, or SOS (state of safety)

Use the battery's safety status as a rating parameter so that the system can keep an eye on it, make sure it operates in a safe environment, and alert users to any potential safety risks. All of these steps will significantly increase the battery system's level of safety. It is not accurate to detect the temperature. Since the confluence is a good thermal conductor and our temperature monitoring point is typically located there, any temperature changes in the cell will cause the heat particles to dissipate, leading to an inaccurate reading.

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