Lithium battery diaphragm thermal shrinkage test method and test equipment

Abstract

The invention discloses a lithium battery diaphragm thermal shrinkage test method and test equipment, which belong to the technical field of lithium batteries. The lithium battery diaphragm thermal shrinkage test method comprises the following steps of selecting a diaphragm sample, placing the diaphragm sample on a diaphragm placing plate, and drawing two mutually perpendicular and crossed line segments at the middle position of the diaphragm sample, namely a transverse line segment AB and a longitudinal line segment CD, measuring the length L1 of the transverse line segment AB and the length L2 of the longitudinal line segment CD, pressing a transparent glass plate on the diaphragm sample, placing the diaphragm sample in an oven which is heated to a target test temperature for heating, performing heat preservation, taking out and cooling, when the diaphragm sample is pressed by the transparent glass plate and the diaphragm placing plate, measuring the length L3 of the transverse line segment AB and the length L4 of the longitudinal line segment CD, and calculating the thermal shrinkage rate of the diaphragm sample. The real working state is simulated, the thermal shrinkage rate of the diaphragm sample is calculated, and direct measurement can be performed without taking out the diaphragm sample.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a testing method and testing equipment for thermal shrinkage of a lithium battery diaphragm. Background technique [0002] Lithium-ion battery is currently the battery system with the best comprehensive performance. It has the characteristics of high specific energy, high cycle life, small size, light weight, and no pollution. It has rapidly developed into a new generation of energy storage power supply for information technology and electric vehicles. , hybrid vehicles and aerospace and other fields of power support. In the structure of lithium batteries, the diaphragm is one of the key components, which has the function of allowing electrolyte ions to pass through, and is used to separate the positive and negative electrodes to prevent short circuit due to contact. The performance of the separator plays a decisive role in the interface structure and internal resistan...

AI Technical Summary

Problems solved by technology

Before and after the test, the steel ruler was used to measure the length with an accuracy of 0.1mm or 0.05mm. This measurement accuracy and the error of human observation readings have a great influence on the coating amount between the positive electrode-diaphragm-negative electrode-diaphragm inside the battery. It may be due to human error that a short circuit may occur due to the shrinkage of the diaphragm when the positive and negative electrodes of the battery are at high temperature, causing a safety accident

In addition, the diaphragm is in a bound state in the battery, and the A4 paper used for heat shrinkage testing is equivalent to a free state. There will be a large deviation between the measured shrinkage rate and the actual application process shrinkage

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