Static balanced method of battery management system of electric vehicle

Abstract

The invention relates to a lithium-ion battery in a new-energy electric vehicle, in particular to a static balanced method of a battery management system of the electric vehicle. The static balanced method of the battery management system of the electric vehicle carries out balance by using a singlechip, a digital circuit, a light insulation relay, a super-capacitor and other technologies, and relying on a voltage acquisition module in the battery management system when the electric vehicle is in a static state, namely, a current is smaller than 0.05C of a battery capacity. A balancing mode comprises (1) using the super-capacitor to achieve moving of energy, namely, electric energy is moved from a battery in high electromotive force to a battery in low electromotive force; (2) using high-power resistor to carry out discharging of a whole group of batteries; combining two modes in the step (1) and the step (2), and meanwhile combining the characteristics that the time when a majority of electric vehicles are in the static state is long, and finally achieving capacity balance of batteries in the whole electric vehicle. The static balanced method of the battery management system of the electric vehicle solves the problems that the service life of power batteries is shortened because capacities of the power batteries are unbalanced in the process of use, and the like.

Description

technical field [0001] The present invention is an equalization scheme formulated for the unbalanced capacity of each battery in the long-term use of lithium-ion power batteries in the field of new energy electric vehicles, and the technical scheme is realized by a battery management system. Background technique [0002] With the increasing shortage of oil resources in the world and the deteriorating environmental pollution caused by motor vehicles, energy-saving and environment-friendly electric vehicles have become a strategically important industry that has attracted worldwide attention. Lithium-ion battery pack is the main source of power for electric vehicles, and its working stability and service life directly affect the performance of the vehicle. Lithium-ion battery packs have different battery self-discharge rates and long-term accumulation, resulting in differences in battery capacity; during battery use, due to differences in the use environment such as temperatur...

AI Technical Summary

Problems solved by technology

[0003] 1. The current equalization method is based on the voltage at both ends. The battery terminal voltage collected by the management system in the dynamic mode cannot really reflect the electromotive force of the battery (the terminal voltage includes the battery electromotive force, the voltage generated by the ohmic internal resistance, and the polarization internal resistance to generate the sum of voltage), in which the battery electromotive force really reflects the capacity of the battery, and the other two will cause an error in balance

Therefore, balancing in this state cannot achieve the effect of equilibrium;

[0004] 2. The balance method is realized by switching tubes such as MOS tubes. In the dynamic mode, the electromagnetic interference of the whole vehicle is very strong, and it is easy to break down the switching tubes, which will cause serious consequences of battery self-discharge or even short circuit.

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