Battery management circuit, battery management system, electric vehicle and battery management method

Abstract

The embodiment of the invention discloses a battery management circuit, a battery management system, an electric vehicle and a battery management method. The battery management circuit comprises a power supply interface, a plurality of branches and a control unit. The battery interface in each branch is coupled with a battery unit, and the cathode connecting end of the battery interface is coupled and grounded through a branch switch unit and a current detection unit. Each branch switch unit comprises a switch element used for switching on / off the branch and a diode with the conduction direction pointing to the negative electrode connecting end of a battery. The control unit drives the branch switch units to be conducted to form a second conductive path replacing a first conductive path or disconnect the second conductive path according to whether the changes of the current values in the branches reach a threshold, so that the elements are prevented from being overheated. When there is a voltage difference between the batteries, the diodes in the branches with lower voltages are cut off by a reverse bias voltage, so that charging and discharging between the batteries are avoided. In addition, a slow-start main switch unit can avoid spark generation caused by sudden current change. A perfect battery hot plug scheme is realized.

Description

technical field [0001] The present application relates to the technical field of battery management, in particular to a battery management circuit, a battery management system, an electric vehicle and a battery management method. Background technique [0002] At present, the application of electric vehicles is becoming more and more extensive. Many electric vehicles adopt the technical solution of multiple batteries connected in parallel for power supply. How to realize hot-swapping when replacing batteries has become an urgent problem to be solved. [0003] When multiple battery modules are directly connected in parallel, it is necessary to ensure that the voltages between the batteries are very close, otherwise there will be problems such as instantaneous discharge causing battery overheating, mutual charge and discharge between batteries, etc., which may easily cause the battery to overheat and catch fire. Therefore, it is not possible to directly and simply connect multi...

AI Technical Summary

Problems solved by technology

However, on the one hand, in the high-current application scenarios of electric vehicles, such a solution will cause high heat generation of circuit components and poor efficiency; on the other hand, when the input terminal of the power consumption system has a large input capacitance, the The battery is connected by plugging and unplugging. When the battery is connected, a large pulse current will be generated at the moment

This pulse current time is usually within one millisecond, but the current may be as high as hundreds of amperes, which will easily cause the over-current protection of the battery management system (BMS) to activate the load and fail to start smoothly; in addition, it will also be caused by this pulse Electrical current causes sparks at connector contacts

However, the current solution cannot solve the problem of sparks at the battery contacts due to instantaneous high current when the battery is hot-swapped.

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