A detection circuit and method for the total voltage and insulation resistance of a battery pack

Abstract

The invention discloses a detection circuit and method for the total voltage and insulation resistance of a battery pack, wherein the circuit includes resistors R1, R2, R3, R4, R5 and switches S1, S2, S3, one end of the resistor R1 is connected to the PACK+ of the battery pack terminal, the other end is connected to the PACK‑ of the battery pack in series with resistors R2 and R3 in sequence, the connection between resistor R1 and resistor R2 is connected to the body ground through switch S1, resistor R4 and switch S2 are connected in parallel to resistor R1 after being connected in series, and resistor R5 After being connected in series with the switch S3, it is connected in parallel with the series circuit composed of the resistor R2 and the resistor R3; the resistor R3 is a sampling resistor, and the ADC sampling module samples the voltage at both ends of the resistor R3 and sends it to the control module, and the control module outputs control signals to control the switches respectively S1, S2, and S3 are closed and disconnected, and the total voltage and insulation resistance are calculated according to the voltage of the ADC sampling module. The invention has a simple structure, only needs one AD sampling, reduces the required number of resistors and switches, has low calculation complexity, and can quickly calculate the insulation resistance and the total voltage.

Description

technical field [0001] The invention belongs to the field of power battery detection and testing, and particularly relates to a detection circuit and a detection method for the total voltage and insulation resistance of a power battery pack. Background technique [0002] With the rapid development of new energy electric vehicle technology, there are more and more types of electric vehicles, such as commercial vehicles, passenger vehicles, special vehicles and low-speed vehicles. These different types of electric vehicles have different applications due to their different applications. Battery pack voltage ratings also vary. The rated voltage of the low-speed electric vehicle battery pack is 72V, and the operating voltage range is 60V to 84V. In the prior art, the detection circuits for the total voltage and insulation resistance of the battery pack are independent, requiring multiple hardware sampling points, complex circuit structure, and high cost. . In the prior art, in...

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Problems solved by technology

The rated voltage of the low-speed electric vehicle battery pack is 72V, and the working voltage range is 60V to 84V. In the prior art, the detection circuits for the total voltage of the battery pack and the insulation resistance are independent, requiring multiple hardware sampling points, the circuit structure is complex, and the cost is relatively high.

In the prior art, in the insulation resistance calculation method based on the unbalanced bridge, after artificially changing the resistance value of the positive pole of the battery pack or the negative pole of the battery pack to the ground, two equations containing the resistance of the positive pole of the battery pack and the negative pole of the battery pack to the ground are obtained, Directly combine two equations to solve, the operation is complicated

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