Method for detecting self-discharge current of battery cell

A technology of battery cells and self-discharge, which is applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., and can solve problems such as the failure of the equipment to start up normally, the difference in series voltage, and the overall low capacity of the battery pack.

Inactive Publication Date: 2020-04-10
ZHUHAI COSMX BATTERY CO LTD
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

However, self-discharge makes lithium batteries prone to low-voltage and zero-voltage failures during long-term storage; or when more than two lithium batteries are connected in series and parallel, series voltage differences are prone to occur, resulting in low overall capacity of the battery pack. It may cause the device to fail to boot normally

Method used

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  • Method for detecting self-discharge current of battery cell
  • Method for detecting self-discharge current of battery cell
  • Method for detecting self-discharge current of battery cell

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preparation example Construction

[0049] The preparation method of the present invention will be further described in detail in conjunction with specific examples below. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

[0050] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

Embodiment 1

[0052] Select three 4.45V batteries with the same preparation method and composition, charge and discharge at 0.02C rate, and obtain the dV / dQ diagram; test their K values ​​at 3.94V, which are 0.015mV / h and 0.045mV / h respectively , 0.08mV / h; the self-discharge current calculated by I=K / F(V) is 57μA / h, 196μA / h, and 309μA / h. Such as Figure 4 with Figure 5 shown.

Embodiment 2

[0054] Select three 4.40V system batteries with the same preparation method and composition, and measure their K values ​​at 3.97V as 0.03mV / h, 0.051mV / h, and 0.084mV / h; according to the known K value of a certain voltage range, I=K / F(V); Since I remains unchanged and the F(V) curve is known, the K value at a certain voltage can be obtained, and the theoretical calculation of the K value at 3.944V, 3.941V, and 3.90V is 0.0305mV respectively / h, 0.057mV / h, 0.108mV / h; the actual test value error is within 3%. The results are shown in the table below.

[0055]

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Abstract

The invention provides a novel method for detecting the quality of a lithium battery / battery pack. According to the method, the self-discharge current of the battery is predicted through the self-discharge current of the battery; the method for the self-discharge current of the battery cell comprises the following steps: 1) charging and discharging a sample battery, simulating a self-discharge process of the sample battery to obtain a V-Q curve of the sample battery, and differentiating the V-Q curve to obtain a dV / dQ-V curve; 2) testing the K value of the sample battery under each voltage inthe long-term placement process; 3) calculating the self-discharge current of the battery cell according to the following formula: F (V) = dV / dQ = dV / d (T * I) = dV / d (T) * / I = K / I; i=K / F(V). The change degree of the battery self-discharge current obtained by the method under different voltages is very small, the influence of voltage change is avoided (the existing K value detection value fluctuates under different voltages), and the quality and the storage time of the battery can be more accurately predicted.

Description

technical field [0001] The invention belongs to the technical field of soft-pack lithium-ion battery manufacturing. The proposal relates to a method for detecting the self-discharge current of battery cells, which is suitable for the method of accurately detecting the self-discharge current of battery cells. The lithium battery can be further judged by the method / The quality of the battery pack is good or bad. Background technique [0002] With the development of science and technology, portable devices have become an indispensable daily necessities in people's lives; and lithium batteries have always been a popular choice for portable devices (such as mobile phones, laptops, tablets, Bluetooth headsets, etc.) due to their high energy density and long standby time. etc.) with the preferred power supply. However, there is a self-discharge phenomenon in the placement process of lithium-ion batteries, which limits its application environment. Contents of the invention [...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/385G01R31/387G01R31/378
CPCG01R31/3865G01R31/387G01R31/378
Inventor 邹浒
Owner ZHUHAI COSMX BATTERY CO LTD
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