Method for dynamically evaluating battery consistency

Abstract

The invention discloses a method for dynamically evaluating battery consistency. The method comprises steps of (1) carrying out series connection of two batteries to be measured to form a battery group to be measured, (2) carrying out the series connection of the battery group to be measured and a load to form a loop, (3) carrying out constant current discharging or charging on the battery group to be measured and collecting the voltage and discharging capacity or charging capacity of the batteries, (4) changing the load which is in series connection in the step (2), (5) carrying out constant current discharging or charging on the battery group to be measured and collecting the remaining capacity of each battery to be measured and the polarization voltage of the battery, (6) calculating the dynamic DC resistance of each battery to be measured according to the collected data, (7) calculating the consistency coefficient of each battery to be measured according to the above data, and (8) judging the consistency of the batteries to be measured according to the consistency coefficient of each battery to be measured. Through measuring and comparing the data of the batteries in parallel connection in a dynamic environment, the essential difference of a battery group can be directly identified, the group performance of the batteries can be improved, the consistency of the batteries is improved, and the service life of the battery group is prolonged.

Description

technical field [0001] The invention relates to a method for evaluating batteries, in particular to a method for dynamically evaluating battery consistency. Background technique [0002] With the depletion of oil and the gradual enhancement of people's awareness of environmental protection, electric vehicles with the advantages of high efficiency, energy saving and zero emission have attracted much attention. They are the main direction of energy-saving and environmentally friendly vehicles and the direction of the future development of the automobile industry. [0003] The battery pack is the core component of an electric vehicle. The battery pack is composed of many single cells connected in series or parallel. Intensified, manifested as battery capacity attenuation, and even overcharging or overdischarging of individual cells, which brings safety hazards to electric vehicles, and at the same time increases the use cost of battery packs and decreases economic performance, ...

AI Technical Summary

Problems solved by technology

However, the determination of the consistency of the battery cells is now carried out under static conditions, mainly based on the internal resistance, voltage and capacity of the battery cells tested under constant current discharge, and based on this, the consistency of the batteries is classified and selected.

The consistency of batteries screened by this method can only reflect the consistency of voltage, capacity and internal resistance of a single battery in this environment and conditions, and cannot reflect the dynamic consistency of batteries when they are used in series or parallel. Conditions change, and its consistency will change significantly

However, the environment in which battery packs are used in electric vehicles is complex, the batteries are often used in parallel and in series, and the current changes frequently. The existing single battery consistency evaluation methods cannot meet the needs of the entire vehicle for battery consistency.

[0005] Therefore, the development of a new battery consistency evaluation method to overcome the existing evaluation methods that cannot accurately identify the consistency difference of the battery, resulting in poor performance after the battery is grouped, has become an urgent need to solve the marketization of electric vehicles. The problem

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