The use of large battery arrays as an energy storage system for backup and continuous power supply is gaining increasing attention, as demonstrated by Tesla Motors' recent introduction of the Powerwall system for home and business use. Batteries in these systems are continuously charged by the grid or other energy sources, and then supplied to the user with alternating current (AC) power through a DC/AC inverter.
Using batteries as a backup power source is nothing new, and there are already many battery backup power systems, such as the basic 120/240V Short-term AC and hundreds of watts of desktop PC backup power system, thousands of watts of vehicle and ship backup power system used by ships, hybrid vehicles or all-electric vehicles, grid-level backup power system used by telecommunications systems and data centers (see Figure 1)... And so on. While advances in battery chemistry and battery technology are getting a lot of attention, there is an equally critical component to a viable and battery-based backup system: Battery management systems (BMS).
The backup power supply according to the battery is ideal for fixed and mobile use of power from a few kilowatts to hundreds of kilowatts, providing reliable and efficient power for a variety of uses.
There are many challenges to completing a battery management system for energy storage and use, and the solution is not simply "extending" a management system for small, low-capacity battery packs. Instead, new, more sophisticated strategies are needed, with key supporting components.
The starting point that should fight is, the measurement value that asks a lot of key battery parameter has high accuracy and credibility. In addition, the planning of the subsystem must be modular so that the configuration can be customized to the specific needs of the use, taking into account possible scaling requirements, overall administration issues, and necessary maintenance.
The working environment of larger storage arrays also presents other significant challenges. The BMS must also supply accurate, common data in noisy and often hot electrical environments, where the inverter voltage/current is high and the resulting current spike occurs. In addition, the BMS must provide a wide range of "fine" data for internal module and system temperature measurements, rather than a limited number of rough totals, which are essential for charging, monitoring and discharging.
Because of the important effect of system of these power supply, because this their working reliability has innate crucial sex. To make this easily stated goal a reality,BMS must ensure data accuracy and integrity and continuous health assessments so that BMS can continue to take required actions. Achieving robust planning and reliable security is a multi-stage process in which the BMS must anticipate possible problems for all subsystems, perform self-testing and provide fault detection, and then select appropriate actions in standby mode and working mode. Finally, because of the high voltage, high current and high power, BMS must meet many stringent regulatory standards.
Systems planning transforms concepts into real-world outcomes
While monitoring rechargeable batteries is conceptually simple by placing voltage and current measurement circuits at the battery terminals, the reality of BMS is quite different and much more complex.
Robust planning begins with thorough supervision of each cell, which raises some important requirements for mimicry circuit functionality. Battery readings need to be accurate in millivolts and milliamps, and voltage and current measurements must be synchronized to calculate power. The BMS must evaluate the validity of each measurement as it needs to maximize data integrity, while the BMS must also identify incorrect or problematic readings. BMS cannot ignore unusual readings, which may indicate a potential problem, but at the same time,BMS cannot act on faulty data.
