Company News
Battery Management System (BMS)
Release time:2020/8/4 13:47:10
Overview
The battery management system (BMS) is a control system that protects the safety of the power battery. It monitors the status of the battery at all times, and takes necessary measures to alleviate the inconsistency of the battery pack, so as to ensure the safety of the use of new energy vehicles.
As a domestic high-quality power system supplier, Hengrun Technology has strong strength and rich experience in the development of control systems, and can provide customers with high-quality engineering and supporting services in the development of battery management systems.
BMS hardware topology
The topology of BMS hardware is divided into two types: centralized and distributed.
The centralized type is to concentrate all the functions of the battery management system in one controller. It is more suitable for the occasions where the battery pack capacity is relatively small and the modules and battery pack types are relatively fixed, which can significantly reduce the system cost.
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Distributed is to separate the main control board and the slave control board of the BMS, and even separate the low-voltage and high-voltage parts, to increase the flexibility of system configuration and adapt to modules and battery packs of different capacities and different specifications.
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Aiming at the inconsistency of the battery in the manufacturing and use process, and the change of battery capacity and internal resistance with the battery life cycle, the Hengrun technology team creatively applies multi-state joint estimation, extended Kalman filter algorithm, internal resistance/capacity online identification, etc. Method to achieve high-precision state estimation of the battery life cycle. According to calculations, for the ternary lithium battery, the estimated deviation of the SOC of the single cell at room temperature can reach a maximum of 2%, and the average estimated deviation is 1%.
At the same time, in view of the inconsistency between battery cells, a balancing strategy based on the same remaining charge capacity is used to maximize the energy efficiency of the battery.
The internal short circuit of the battery is the most complicated and difficult to determine the cause of thermal runaway. It is an international problem in the field of battery safety and can lead to catastrophic consequences. The internal short circuit of the battery cannot be fundamentally eliminated. At present, the problem is detected early through long-term (more than 2 weeks) shelving observation.
In terms of battery internal short circuit identification, Hengrun Technology has more than 10 world-leading patents and patent licenses. Using symmetrical loop circuit topology (SLCT) and related algorithms, it is possible to perform batch internal short circuit detection on multiple battery cells in a very short time (within 5 minutes), and can identify internal short circuits of the order of 0~100kΩ and accurately estimate them Internal short resistance value. This method can significantly reduce the operating costs of battery cell manufacturers or module assembly manufacturers, and improve the safety of battery production and use processes.
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