Lithium battery capacity fading rate calculating method

Abstract

The invention discloses a lithium battery capacity fading rate calculating method, and belongs to the technical field of a power battery. The lithium battery capacity fading rate calculating method includes the steps: in a constant temperature environment condition, setting a circulation process step for taking a circulation test for an experiment lithium ion battery, periodically measuring the alternating current internal resistance of the lithium ion battery, and obtaining the capacity fading rate and the internal resistance increment rate of the experiment lithium ion battery; according to the capacity fading rate and the internal resistance increment rate of the experiment lithium ion battery, establishing a capacity fading rate-internal resistance increment rate model; and according to the internal resistance increment rate of the lithium ion battery to be detected, and utilizing the capacity fading rate-internal resistance increment rate model to calculate the capacity fading rate of the lithium ion battery to be detected. By establishing the capacity fading rate-internal resistance increment rate model for the lithium ion battery, according to the internal resistance increment rate of the lithium ion battery, the lithium battery capacity fading rate calculating method can obtain the capacity fading rate of the lithium ion battery, is suitable for any lithium ion batteries, and has strong universality and higher practicality.

Description

technical field [0001] The invention relates to the technical field of power batteries, in particular to a method for calculating the capacity decay rate of a lithium-ion battery. Background technique [0002] With the rapid development of new energy vehicles, battery life, one of the important performance indicators of lithium-ion batteries, is attracting increasing attention. In the field of power batteries, after the battery capacity drops to 80% of the rated capacity, lithium-ion batteries will no longer be used in electric vehicles. Therefore, it is necessary to predict the service life of the lithium-ion battery, so as to stop using the battery in time when the battery capacity drops to 80%. [0003] The battery life includes storage life and cycle life. At present, the methods for predicting the service life of lithium-ion batteries are roughly divided into model-based prediction methods and data-driven methods. In addition, the patent application number 20151037302...

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Problems solved by technology

[0004] However, the above-mentioned current prediction methods all have different defects: the model-based prediction method uses lithium-ion batteries for testing, and the data obtained from the test is relatively intuitive, but due to the differences between batteries, the test results will be inconsistent. representative

The method proposed in the patent with the application number 201510373029.9 is only under the condition of full charge, considering the influence of temperature on the storage life of the battery, and establishing an aging model of battery capacity attenuation, which has relatively large limitations.

The patent application number 201310683449.8 establishes the battery capacity decay rate Q loss The function model between the battery discharge times N: However, the meanings of the coefficients A and B in the model are not clear, and each battery must establish a corresponding model to calculate the capacity decay rate, so the model is not universal

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