cr2032 button battery.Multi-channel voltage acquisition circuit for electric vehicle battery management system

　　Multi-channel voltage acquisition circuit for electric vehicle battery management system

　　This article introduces a novel multi-channel voltage acquisition circuit in the battery management system. This circuit is used to collect the voltage of a large number of battery cells. It can significantly reduce the area of the circuit board and reduce the cost, while affecting the measurement accuracy. Not big.

　　In view of some problems that occur in software simulation and practical application of circuits, this article analyzes their causes and improves them.

　　The battery is the main power source of electric vehicles. In order to ensure the normal and safe driving of electric vehicles, the battery management system must monitor the voltage data of the electric vehicle battery in real time. The voltage data is obtained through the voltage acquisition circuit and A/D conversion. In order to avoid safety problems caused by local overcharge/overdischarge caused by battery imbalance, the monitoring system is required to accurately measure the voltage of each cell or several cells. If the traditional multi-channel voltage collection method is used, when the number of battery cells is large, the design and implementation of the entire management system will have shortcomings such as high cost and poor consistency. This paper designs a novel multi-channel voltage acquisition circuit based on lead-acid batteries for electric vehicles.

　　Hardware structure of voltage inspection in battery monitoring system

　　Generally, electric vehicles are equipped with 10 to 30 batteries, and the single (module) voltage range is 3 to 20V. When the batteries are used in series, the battery terminal voltage will reach more than 200V.

　　This article proposes a design idea as shown in Figure 1. The design uses a shift switch circuit to sequentially select the circuit under test, and collects single-channel data through A/D to complete data collection. This design approach has the following advantages:

　　1. The circuit is simple. Simplify the PCB board making and wiring process.

　　2. Fewer devices are used and the cost is low. The main cost in the acquisition circuit comes from the ADC, and this circuit only requires one ADC.

　　3. It can solve the problem of poor consistency caused by uneven parameters of chips such as operational amplifiers.

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