A complete battery energy storage system, commonly known as BESS, can be strategically assembled together from dozens, hundreds, or even thousands of lithium-ion batteries, depending on the application. The rated voltage of these systems may be less than 100V, but may be as high as 800V, with a battery pack supply current range of up to 300A or greater. Any mismanagement of high-voltage battery packs can lead to catastrophic disasters that endanger lives. Therefore, BMS is crucial for ensuring safe operation. The benefits of BMS can be summarized as follows.
Functional safety. It goes without saying that for large-sized lithium-ion battery packs, this is particularly cautious and necessary. But as is well known, even smaller formats used in laptops can catch fire and cause significant damage. There is almost no room for battery management errors in the personal safety of users of products containing lithium-ion power systems.
Lifetime and reliability. Battery pack protection management, electrical and thermal, ensuring that all batteries are used within the declared SOA requirements. This subtle supervision ensures the safe use of batteries and fast charging and discharging cycles, and inevitably generates a stable system that may provide years of reliable service.
Performance and scope. BMS battery pack capacity management, which uses battery to battery balance to balance the SOC of adjacent batteries on battery pack components, allowing for optimal battery capacity. Without this BMS function to consider changes in self discharge, charging/discharging cycles, temperature effects, and general aging, the battery pack may eventually become useless.
Diagnosis, data collection, and external communication. The supervisory task includes continuous monitoring of all battery cells, where data records themselves can be used for diagnosis, but are typically used for computational tasks to estimate the SOC of all batteries in the component. This information is used for balancing algorithms, but can be jointly forwarded to external devices and displays to indicate available resident energy, estimate expected range or range/lifespan based on current usage, and provide the health status of the battery pack.
Reduce costs and warranty. The introduction of BMS in BESS increases costs, and battery packs are expensive and potentially dangerous.
The more complex the system, the higher the security requirements, thus requiring more BMS supervision. However, BMS's protection and preventive maintenance in terms of functional safety, lifespan and reliability, performance and scope, diagnosis, and other aspects ensure that it will reduce overall costs, including warranty related costs.
