Abstract:

Aiming at the problem of high common-mode voltage in the single-cell voltages measurement of high voltage battery packs, a sampling circuit using INA117 as the sampling chip is proposed. Based on the detailed introduction of the characteristic of INA117, the design of the sampling circuit is completed. The leakage current of each battery pack is theoretically calculated, and the consistency of single cells is increased by adding balancing resistors. The problem of large differences for the single cell voltage in the 70 V battery management system of a certain satellite is successfully solved, achieving the purpose of long-term use or storage. The proposed calculation formula of the leakage current of each battery pack provides a theoretical basis for the design of other high voltage battery management system products, increasing product reliability and reducing design time.

Key words: high voltage battery packs, measurement of single cell voltage, INA117, leakage current