For the charging voltage difference of power wall lithium battery, it is preferred to check the BMS protection board. The full name of BMS is battery management system and battery management system. It is a device combining the state of home battery energy storage, mainly for intelligent management and maintenance of each battery unit, to prevent battery charging and discharging, to extend the service life of the battery, and to monitor the state of the battery. Generally, a BMS is represented as a circuit board or a hardware box.
BMS is one of the core subsystems of home battery energy storage system. It is responsible for monitoring the operation status of each battery in the battery storage unit to ensure the safe and reliable operation of the energy storage unit. BMS can monitor and collect status parameters of energy storage battery (including but not limited to single battery voltage, battery column temperature, battery circuit current, lifepo4 lithium battery pack terminal voltage, battery system insulation resistance, etc.), And execute the necessary state parameters to obtain more analysis and calculation of system state evaluation, and achieve effective control over the energy storage battery body according to specific protection control strategies to ensure the safe and reliable operation of the Wall mounted energy storage battery unit. At the same time, BMS can interact with other external equipment (PC, EMS, fire protection system, etc.) Through its own communication interface and analog/digital input interface, the linkage control of all subsystems in the entire energy storage power station is formed to ensure safe and reliable power generation and efficient grid connection operation of the power station.
Architecture
From the perspective of powerwall 20 kwh, BMS can be divided into centralized and distributed according to different project requirements.
Centralized BMS
To put it simply, a centralized BMS uses one BMS hardware to collect all the cells, which is suitable for scenarios with fewer cells.
Centralized BMS has the advantages of low cost, compact structure and high reliability. It is commonly used in scenarios with small capacity, low total voltage, and small battery system volume, such as electric tools, robots (handling robots, help robots), Internet of Things smart homes (cleaning robots, electric vacuum cleaners), electric forklifts, and electric low-speed vehicles (electric bicycles, electric motorcycles, electric tourist vehicles, electric patrol vehicles, electric golf carts, etc.), Light hybrid vehicle.
BMS hardware with centralized architecture can be divided into high voltage area and low voltage area. The high-voltage area is responsible for collecting the voltage of single battery, collecting the total voltage of the system, and monitoring the insulation resistance. Low voltage area includes power circuit, CPU circuit, CAN communication circuit, control circuit, etc.
With the continuous development of passenger vehicle power wall battery system towards high capacity, high total voltage and large volume, BMS with distributed architecture is mainly applied to plug-in hybrid and pure electric vehicles.
Distributed Building Management System
At present, the industry calls distributed BMS in a variety of ways, different companies, different names.