Hierarchical battery balance judgment circuit and balance management circuit based on analog sampling

Abstract

The invention discloses a hierarchical battery balance judgment circuit and balance management circuit based on analog sampling, including 2 n A power supply formed by connecting single batteries in series, n is the total number of levels; in the i-th level, 2 i‑1 Two adjacent single batteries are used as a battery unit, and two adjacent battery units form a group. Each group of battery units uses an analog sampling amplifier circuit to obtain a voltage difference sampling signal, and judges whether it is balanced according to the voltage difference sampling signal; analog sampling amplification In the circuit, the first preamplifier circuit obtains 1 / 2 of the total voltage of the near-earth battery unit n‑1 To sample the voltage, the second preamplifier circuit obtains 1 / 2 of the total voltage of the two battery cells connected in series n is the sampling voltage; the sampling voltage is amplified with the same amplification factor and input to the differential circuit to obtain a voltage difference sampling signal. The balance management circuit uses the balance judgment circuit to judge that the battery cells in the same group are unbalanced, and controls the balance circuit to balance the battery cells in the same group. The invention has fast sampling and equalization speed, high precision and strong expandability.

Description

technical field [0001] The invention relates to the technical field of balancing lithium batteries, in particular to the technical field of balancing battery packs connected in series. Background technique [0002] Today, as the global energy crisis continues to intensify, people's awareness of environmental protection is gradually increasing, and they are more concerned about energy pollution and emissions. In the automotive field, electric vehicles have become the main trend of current research due to their energy-saving, high-efficiency, low noise, and zero-emission characteristics. The battery pack is an essential and important part of electric vehicles. In the process of its research, different batteries such as lead-acid batteries, nickel-metal hydride batteries and lithium-ion batteries have been applied to electric vehicles. Lithium batteries are due to Its small size, light weight, low self-discharge rate, high energy density and other advantages have gradually bec...

AI Technical Summary

Problems solved by technology

The most common method is to obtain the sampling voltage through resistor division and directly input it into the single-chip microcomputer. However, due to the influence of the ADC input internal resistance in the single-chip microcomputer, the voltage detection deviation is too large, resulting in low sampling accuracy; another method is to use a voltage acquisition chip. For data collection, for example, TI's BQ76930 chip, ADI's LTC6804 and AD7606 chips can more accurately collect the voltage of each series battery in the battery pack, but the sampling chip is expensive and the control system is complicated, which greatly increases the balance management system. cost

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