BMS constant-current pre-charging circuit

Abstract

The invention relates to the technical field of battery management systems, in particular to a BMS constant-current pre-charging circuit which comprises a constant-current source pre-charging circuit, one end of the constant-current source pre-charging circuit is connected with an external capacitor C, and the other end of the constant-current source pre-charging circuit is connected with an external pre-charging relay K2. The capacitor C is also connected with an external battery pack through an external main relay K1; the constant current source pre-charging circuit comprises an MOS tube M1, a bias resistor R2, a Zener diode ZD1 and a resistor R1. According to the BMS constant-current pre-charging circuit, the constant-current source pre-charging circuit is used for carrying out constant-current pre-charging on the capacitor C at the load end, no large instantaneous impact current exists in the pre-charging process, the type selection specifications of a pre-charging relay and a current-limiting resistor are effectively reduced, the size of the relay is further reduced, the cost is reduced, and the circuit reliability is improved.

Description

technical field [0001] The invention relates to the technical field of battery management systems, in particular to a BMS constant current precharging circuit. Background technique [0002] BMS (BATTERY MANAGEMENT SYSTEM, battery management system) is a system for monitoring and controlling the battery. It can feed back the collected battery information to the user in real time, and adjust parameters according to the collected information to achieve the purpose of fully utilizing the battery performance. In general, a pre-charging process is required before the BMS high-voltage switch is closed, that is, before the main relay switch is closed, in order to avoid excessive instantaneous inrush current, it is necessary to charge the DC Link (DC support capacitor, also known as DC- Link capacitor) capacitor C is precharged, and the main relay is closed when the capacitor C is charged close to the battery voltage. It can be seen that the traditional pre-charging working method i...

AI Technical Summary

Problems solved by technology

D) Repeated pre-charging causes repeated impact on the current-limiting resistor, resulting in short life and low reliability of the current-limiting resistor

E) It is impossible to diagnose whether the adhesion of the main relay and the pre-charge relay is invalid

F) When the pre-charging fails, the pre-charging timeout, or the pre-charging relay adhesion failure, the pre-charging resistance is always working, the power consumption is large and it is easy to cause the components to burn out

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