Method for quantitatively determining flatness of battery cell

Abstract

The invention provides a method for quantitatively determining the flatness of a battery cell, which belongs to the technical field of measurement of the flatness of the battery cell of a lithium ion battery, and comprises the following steps that S1, the battery cell to be measured is put on a test board of a measuring tool, and the measuring tool is started; S2, the measuring end of the measuring tool is in contact with the battery cell and extrudes the battery cell, the minimum pressure is 20 Kgf, a first battery cell thickness value f(1) is obtained under the minimum pressure, the pressure of the measuring tool is gradually increased for multiple measurements, the single pressure is increased by 30 Kgf, the thickness change rate K(n) is obtained according to the formula K(n)=1-f(n) / f(n-1), the variable quantity G(n) of the thickness change rate is obtained according to the formula G(n)=K(n)-K(n-1); and S3, the variation G(n) of the thickness change rate is subtracted from the battery cell thickness value f(1) measured for the first time to obtain a cell thickness value measured when the variation G(n) of the thickness change rate is a negative value for the first time to obtain a flatness numerical value. The method is simple to operate and accurate in measurement result, the flatness of the battery cell is quantitatively determined under the condition of meeting low-cost measurement conditions, and engineering technicians can be better helped to research the assembly characteristics of the soft package battery.

Description

technical field [0001] The invention belongs to the technical field of cell flatness measurement for lithium ion batteries, and relates to a method for quantitatively determining the cell flatness. Background technique [0002] In the prior art, the methods for measuring the flatness of the pouch cell are mainly visual observation or laser scanning. The naked eye observation method is commonly known as the visual inspection method, which uses visible light to observe the surface state of the battery cell. It is a rough and non-quantifiable observation method. Although visible light observation is fast, it cannot quantitatively give the difference in the flatness of the battery cell. The laser scanning method is to use optical equipment to scan the entire outline of the cell to make a 3D model, and then calculate the difference between the overall thickness value and the thickness value of the section. Although it can be measured quantitatively, the equipment is expensive and...

AI Technical Summary

Problems solved by technology

The naked eye observation method is commonly known as the visual inspection method, which uses visible light to observe the surface state of the battery cell. It is a rough and non-quantifiable observation method. Although visible light observation is fast, it cannot quantitatively give the difference in the flatness of the battery cell. ;The laser scanning method is to use optical equipment to scan the entire outline of the cell to make a 3D model, and then calculate the difference between the overall thickness value and the thickness value of the section. Although it can be measured quantitatively, the equipment is expensive and the application is limited.

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