Battery management system (BMS) pre-charging circuit and control method thereof

Abstract

The invention relates to a battery management system (BMS) pre-charging circuit and a control method thereof. The BMS pre-charging circuit includes an AFE front end detection unit, an MCU controller, a short circuit detection unit, a detection resistor, a pre-charging resistor, a pre-charging MOS tube, and a main power MOS tube, and the corresponding control method includes the following steps that S1, a charging current is sampled; S2, the AFE front end detection unit judges whether a sampled charging current value is greater than or equal to a preset overcurrent threshold or not, if yes, the step S3 is performed, otherwise, the step S1 is returned; S3, overcurrent protection is performed; S4, the pre-charging process is performed; and S5, normal power on is recovered. Compared with the prior art, without changing an original connection mode, that is, an external ignition signal is not input, the BMS pre-charging circuit can effectively solve the problem that a power part cannot be powered on normally due to overcurrent protection in the moment of power on.

Description

technical field [0001] The invention relates to the technical field of battery management systems, in particular to a BMS precharging circuit and a control method thereof. Background technique [0002] Lithium batteries have been continuously expanded in the field of power batteries because of their high energy density and very small internal resistance. However, due to the high activity of lithium batteries, they need to be used in conjunction with a battery management system (BMS): external power components (For example: a motor) is usually connected in parallel with a capacitor C with a large capacity. At the moment when the power part is connected to the main power MOS tube, the battery voltage is above 50V, and the voltage of the capacitor C is close to 0. At this time, the load resistance value is only It is the sum of the resistance of the wire and the internal resistance of the main power MOS tube. In order to improve the output capacity of the battery pack, the load...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a BMS pre-charging circuit and its control method in order to overcome the defects of the above-mentioned prior art, without changing the original connection mode of the device, to solve the problem of failure of power components due to over-current protection at the moment of power-on. Problems with normal power-on work

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