Disconnection detection circuit and disconnection detection method of battery management system

Abstract

The invention discloses a disconnection detection circuit and a disconnection detection method of a battery management system. The disconnection detection method comprises the following steps: disconnecting a passive equalization circuit from a detection circuit, and acquiring the voltage across the two ends of a filter circuit as a reference voltage; connecting the passive equalization circuit to the detection circuit, and acquiring the voltage across the two ends of the filter circuit as a comparison voltage; and comparing the reference voltage with the comparison voltage to judge whether a battery connected in parallel with the filter circuit is disconnected from an acquisition circuit. A new use is given to the passive equalization circuit, namely, sampling the voltage of the battery together with the filter circuit. Whether the battery is disconnected from the acquisition circuit can be judged according to the divided voltage of a capacitor in the filter circuit. Disconnection detection can be completed without any additional circuit. Abnormal battery connection can be found in time. The passive equalization circuit can carry out battery voltage equalization, and battery voltage equalization and disconnection detection do not interfere with each other.

Description

technical field [0001] The invention relates to the technical field of battery management systems of electric vehicles, in particular to a disconnection detection circuit and detection method of the battery management system. Background technique [0002] The battery management system (Battery Management System, BMS) is an important bridge connecting the power battery pack and the vehicle controller. It needs to make corresponding and accurate judgments based on the state information of the battery pack, and timely feed back to the vehicle controller. At present, the power battery pack is mainly connected in series to supply power for the whole vehicle, so the BMS needs to accurately sample the voltage of the single cells of the battery pack, and for non-integrated chips, it is necessary to detect whether there is any abnormality in the connection between the single cells and the BMS, so as to avoid The actual data collected is wrong. [0003] The traditional BMS offline de...

AI Technical Summary

Problems solved by technology

The disadvantage of this solution is that in the case of disconnection, the voltage is divided due to the presence of the capacitor 8. When collecting the voltage of the single battery 3, it is necessary to wait for the discharge of the capacitor 8 to collect the voltage to 0, which will cause a delay in the actual collection and judgment.

Images