Lithium ion battery pack available energy calculation method

Abstract

The present invention relates to a lithium ion battery pack available energy calculation method. The method comprises the following steps that: S1, the capacity and median voltage of each lithium ion battery in a lithium ion battery pack to be detected are detected, wherein the lithium ion battery pack to be detected is divided into n battery groups; S2, the distribution function of the capacity of any one Yj of the battery groups is obtained; S3, the expected value EYj and variance Var (Yj) of Yj are calculated according to the distribution function; S4, the critical value Tn of the total capacity Qsum of the n battery groups is calculated; and S5, the total energy En of the n battery groups is obtained, namely, the available energy of the lithium ion battery pack to be detected is obtained. According to the method of the invention, when lithium ion batteries are new lithium ion batteries in the same batch or the use conditions of the lithium ion batteries are identical, the parameters (capacity) of the lithium ion batteries are in normal distribution, and therefore, the available energy of a lithium ion battery pack formed by grouped lithium ion batteries can be calculated through the distribution of the parameters (capacity) of the lithium ion batteries, and therefore, a lithium ion battery manufacturer or a lithium ion battery user can conveniently evaluate the performance of grouped lithium ion batteries under different voltage levels.

Description

technical field [0001] The invention relates to the field of battery management of new energy vehicles, in particular to a method for calculating the available energy of a lithium-ion battery pack. Background technique [0002] In recent years, lithium-ion battery materials and battery manufacturing technology have developed rapidly. Battery manufacturers at home and abroad continue to produce batteries with large capacity, high specific energy and high safety, making lithium-ion batteries widely used in electric vehicles, energy storage and rail transit. [0003] Although the progress in the manufacturing process of lithium-ion batteries has reduced the difference when the batteries leave the factory to a certain extent, after the lithium-ion batteries are connected in series on a large scale, due to the barrel effect of the batteries, the inconsistency of the lithium-ion batteries makes the lithium-ion The actual usable energy of a battery pack is far less than that of a ...

AI Technical Summary

Problems solved by technology

Similarly, during the use of lithium-ion battery packs, the inconsistency of battery aging aggravates the inconsistency of lithium-ion battery parameters, resulting in a rapid decline in the energy utilization rate of lithium-ion battery packs.

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