The LiFePO4 battery management system, BMS (Battery Management System), is an important component of the electric vehicle power LiFePO4 battery system. On the one hand, it detects, collects and preliminarily calculates the real-time status parameters of LiFePO4 battery, and controls the on-off of the power supply loop based on the comparison between the detected value and the allowable value; on the other hand, it reports the collected key data to the vehicle controller and receives control The instructions of the vehicle, and coordinate with other systems on the vehicle. LiFePO4 battery management system, different battery cell types have different requirements for LiFePO4 battery management system.
LiFePO4 battery management system function
Generally speaking, the LiFePO4 battery management system for electric vehicles should achieve the following functions:
1. Accurately estimate the state of charge of the power battery pack:
Accurately estimate the state of charge (StateofCharge, or SOC) of the power LiFePO4 battery pack, that is, the remaining power of the LiFePO4 battery, to ensure that the SOC is maintained within a reasonable range, and prevent damage to the LiFePO4 battery due to overcharge or overdischarge, so as to predict the mixture at any time How much energy is left in the energy storage LiFePO4 battery of a powered car or the state of charge of the energy storage LiFePO4 battery.
2. Dynamically monitor the working status of the power battery pack:
During the charging and discharging process of LiFePO4 battery, the terminal voltage and temperature, charging and discharging current and total voltage of battery pack of each battery in the battery pack of electric vehicles (should be the power LiFePO4 battery pack) are collected in real time to prevent the LiFePO4 battery from overcharging or Over discharge phenomenon. At the same time, it can give the status of the LiFePO4 battery in time, select the problematic battery, and maintain the reliability and efficiency of the entire group of LiFePO4 batteries, making it possible to realize the remaining power estimation model. In addition, it is necessary to establish a history file of each battery to provide information for the further optimization and development of new types of electricity, chargers, motors, etc., and to provide a basis for offline analysis of system failures
3.Balance between single cells and battery packs:
That is, balance between the single LiFePO4 battery and LiFePO4 battery groups, so that each LiFePO4 battery in the LiFePO4 battery group reaches a balanced state. Battery balancing is generally divided into active balancing and passive balancing. Most of the BMSs that have been put on the market currently use passive equilibrium. Equalization technology is the key technology of a battery energy management system that is currently being researched and developed in the world.