Requirements of the vehicle-mounted lithium-ion battery supervision system

Requirements for the vehicle-mounted lithium battery monitoring system At present, the safety mechanism required by the vehicle-mounted lithium battery monitoring system is as follows: It is composed of tens to hundreds of battery cells connected in series to form a battery pack to supply power to its load inverter and motor. Since the voltage of the series battery pack is as high as tens to hundreds of volts, it is impossible to use a single battery monitoring system to monitor all battery cells. Therefore, usually each battery monitoring system (IC) monitors 8-16 batteries at the same time. The battery monitoring IC mainly monitors the voltage, temperature and balance of the battery. In the vehicle battery monitoring system, the battery monitoring IC does not distinguish the voltage measurement of each battery, and only submits the measurement information to the single-chip microcomputer (microcomputer unit). Each battery monitoring IC and MCU constitute a battery monitoring unit. This unit summarizes battery voltage, current, and temperature information, calculates the battery's state of charge, and transmits it to the on-board computer system to control the charging and discharging actions of the battery pack. Figure 2 Examples of three methods to evaluate the measurement accuracy of battery monitoring ICs Therefore, measuring battery voltage is an important function of battery monitoring ICs. Therefore, it is of great significance to evaluate the accuracy of integrated circuit measurement for battery monitoring. Figure 2 shows three typical circuits used to evaluate the measurement accuracy of battery monitoring ICs. At the same time, A) the circuit uses two sets of ICs to perform redundant monitoring of the same battery pack; B) for the measurement accuracy of the IC, a standard voltage source 2 is supplied externally. C) is the standard voltage source that appears inside. Here, A) method can add redundancy, but it also adds the degree of clutter of the system; B) and C) these two methods use standard voltage source 2 independent of the standard voltage source 1 of the A/D converter To convert the voltage A/D to evaluate the measurement accuracy of the IC. However, regarding this independent meter voltage source 2, the possibility of defects caused by the same reason should also be considered. For example, assuming that the standard voltage source 1 and the standard voltage source 2 of the A/D converter use the same circuit, the same power source, and the same load ratio, each voltage source is more likely to change the same output voltage. The effect is that no defects can be detected by this method. In order to solve this problem, the best way is to choose the B) method, which is independent of the regulated voltage source 2 to monitor the external power supply of the IC from the battery, but this may increase the cost. Therefore, if Ann chooses C) at the same time, the independence of the standard voltage source 2 of the A/D converter from the standard voltage source 1 is an important issue. For example, as a means of insisting on independence, choosing different circuits and so on. This aspect involves the internal secrets of various battery manufacturers, so this article will give up. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Silicon carbon anode material is the development focus of lithium battery anode materials