In order to reduce the battery system cost, improve the safety and reliability of the battery system, and improve the automation level of the battery grouping system, it facilitates the use of power batteries in order and life cycle management, modularization, standardization, and intelligentization of power batteries. The demand is getting stronger and stronger.
At present, the mainstream battery management system in China mainly adopts a master-slave architecture. The number of battery sections collected from the slave control module is generally 24 strings and 48 strings.
With the large-scale application of power batteries, the master-slave type of battery management system has gradually exposed some disadvantages in the process of step-by-step utilization and large-scale production:
■ The inability to form standard modules is not conducive to automated scale applications;
■ There is cross-module acquisition, and the guide strips between the modules affect the accuracy of battery voltage acquisition.
■ The length of the battery sampling cable varies, the design is complicated, the wiring is troublesome, and the installation and debugging efficiency is low.
■Because the battery collection harness travels between the modules, there are potential safety hazards such as short circuit and leakage of the battery high-voltage line;
■ The length of the harness, the cost itself is relatively large, the system cost is higher;
■ The poor applicability of this architecture makes it difficult to form automated and standardized production. As a result, PACK assembly costs are high and performance is difficult to guarantee.
■ The design of this architecture did not consider future battery module applications and could not fully exploit the advantages of battery moduleization. When the battery is used in cascades, BMS and battery harnesses need to be disassembled and assembled into groups. The cost is extremely high and the use value of the ladders is almost lost. .
In order to reduce the cost of the battery system and improve the safety and reliability of the battery system, it facilitates the use of power batteries in order and the management of the entire life cycle. The demand for modularization, standardization, and intelligence of the power battery is becoming stronger and stronger. In order to meet the modularization and standardization requirements of the battery pack, this requires a distributed implementation of the battery management system.
The distributed management system integrates a battery module and a battery collection unit to realize an intelligent and standardized battery module. The advantage of this structure is that the assembly process of the module can be simplified, the sampling wire harness is relatively easy to fix, the distance of the wire harness is uniform, there is no problem of different pressure drop, and the battery module is easy to be standardized and modularized, and the use of the battery is convenient. This architecture solves the complex problems of the wiring harness through the bus, and the installation is relatively simple, efficient, and flexible, suitable for different battery pack sizes.