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Method for determining hole closing temperature of diaphragm

A closed-cell temperature and measurement method technology, which is applied in the investigation stage/state change, etc., can solve the problems of high sealing requirements, long measurement time, and leakage of conductive liquid, so as to increase test efficiency, save test time, and avoid The effect of loss

Active Publication Date: 2020-01-07
HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are several disadvantages as follows: 1. High temperature can easily cause the conductive liquid to volatilize and leak, and the high pressure generated will also affect the test results
2. If the measurement time is too long, the conductive liquid will evaporate and leak, which will increase the conductive resistance and affect the test results
3. The test device is relatively complicated and requires high sealing performance
The above method requires high equipment, and the general battery manufacturer may not have the above two equipment

Method used

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  • Method for determining hole closing temperature of diaphragm

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Effect test

Embodiment 1

[0024] A method for measuring the closed cell temperature of a diaphragm. During the temperature rise process, the heat flow difference between the diaphragm sample and the reference object is measured to characterize all physical and chemical changes related to thermal effects, and the DSC curve of the diaphragm sample is calculated. The first-order derivative forms a first-order derivative curve. The temperature corresponding to the highest point of the first-order derivative curve is the fastest heat absorption temperature. At this time, the heated contact area of ​​the diaphragm is the largest, and the diaphragm is completely closed, so this temperature is the complete closed-cell temperature of the diaphragm.

Embodiment 2

[0026] The following uses a differential scanning calorimeter to specifically describe the measurement steps of the closed cell temperature of the diaphragm:

[0027] Step 1. Sample pretreatment: place a diaphragm in an environment with a temperature of 23±2°C and a relative humidity of 50±10% for no less than 4 hours.

[0028] Step 2. Sampling and weighing: Use scissors to cut a piece of diaphragm sample from the geometric center of the diaphragm, use a puncher to punch out a disc with a diameter slightly smaller than the inner diameter of the sample crucible, and take about 5-10 mg of diaphragm sample, accurately to 0.1 mg, spread the diaphragm sample in the sample crucible, cover it, and pierce the center of the cover with a steel needle; weigh the weight of the sample crucible after placing the diaphragm sample, accurate to 0.01 mg.

[0029] Step 3. Temperature scan:

[0030] 3.1 At room temperature, put the sample crucible and reference crucible into the sample chamber, ...

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Abstract

The invention discloses a method for determining a hole closing temperature of a diaphragm. The method comprises the following steps: in a temperature increasing process, measuring a heat flow difference between a diaphragm sample and a reference substance, solving a first-order derivative of a DSC curve of the diaphragm sample, and forming a first-order derivative curve, wherein heat can be absorbed at the fastest speed at a temperature corresponding to the highest point of the first-order derivative curve, at the temperature, the heated contact area of the diaphragm is the largest, holes ofthe diaphragm are completely closed, and the temperature is namely a complete hole closing temperature of the diaphragm. The method disclosed by the invention can obtain multiple experimental resultsby virtue of one test, general thermal properties of the diaphragm can be tested, and the hole closing temperature of the diaphragm also can be detected, so that loss of purchasing a special instrument is avoided, test time is saved and test efficiency is improved.

Description

technical field [0001] The invention relates to a method for measuring the closed cell temperature of a diaphragm. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, high working voltage, no memory effect, long cycle life, and less environmental pollution. With the widespread application of lithium-ion batteries, the safety of batteries has received more and more attention. At present, the safety of lithium-ion batteries is still one of the key issues hindering their large-scale application in electric vehicles, energy storage and other fields. In unexpected situations, lithium-ion batteries may catch fire and explode, causing great personal injury and property loss. [0003] The battery is mainly composed of positive electrode material, negative electrode material, electrolyte and separator. The separator is an important part of the battery. The separator is mainly composed of a microporous film or a non-woven fiber sheet, whi...

Claims

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Application Information

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IPC IPC(8): G01N25/12
CPCG01N25/12
Inventor 袁海朝徐锋豆赛赛苏碧海
Owner HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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