Test method for lithium ion battery ceramic diaphragm porosity

A technology of lithium-ion batteries and ceramic diaphragms, which is applied in the fields of measuring devices, permeability/surface area analysis, suspension and porous material analysis, etc., can solve the problems of poor mechanical properties, cumbersome process, and large impact, and achieve test equipment And the effect of low condition requirements, strong operability and easy process

Inactive Publication Date: 2019-01-18
DO FLUORIDE NEW ENERGY TECHNOLOGY CO LTD
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] If the porosity of the diaphragm is too low, it will lead to poor air permeability and low electrical conductivity, while if the porosity is too high, the puncture ability of the diaphragm will be weakened, the shrinkage rate will increase and the mechanical properties will deteriorate, and there will be safety hazards. It is an important control index in the process, but the composite diaphragm has different densities of different materials, so it is difficult to accurately measure the porosity of the ceramic diaphragm with the traditional weighing method
[0004] At present, there are many methods for testing the porosity of ceramic-coated diaphragms, but the process is cumbersome and the test process cannot be standardized and quantified, and subjective factors have a great influence on the test results

Method used

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  • Test method for lithium ion battery ceramic diaphragm porosity
  • Test method for lithium ion battery ceramic diaphragm porosity
  • Test method for lithium ion battery ceramic diaphragm porosity

Examples

Experimental program
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preparation example Construction

[0025] The preparation method of lithium-ion battery ceramic diaphragm in the specific embodiment comprises the following steps:

[0026] 1) The raw material PP is melted and extruded, and then heat-treated to obtain a polyolefin film after cooling; the pore size of the polyolefin film is between 40 and 100 nm;

[0027] 2) The polyolefin film is stretched longitudinally and transversely, and cut and rolled after heat setting;

[0028] 3) Place the wound-up base film on a coating machine, and coat the ceramic slurry on the surface of the diaphragm to obtain a ceramic coated diaphragm; the ceramic slurry includes alumina particles and a binder, alumina particles and adhesive The mass ratio of the binder is 99:1, and the binder used is a water-based polyacrylic binder; the average particle size of the alumina particles is 0.5 μm.

Embodiment 1

[0030] The test method of the porosity of the lithium-ion battery ceramic diaphragm of the present embodiment, the flow chart is as follows figure 1 As shown, it specifically includes the following steps:

[0031] 1) Take the lithium-ion battery ceramic diaphragm, and use a knife along the steel ruler to cut out a cuboid lithium-ion battery ceramic diaphragm of an appropriate size as the sample to be tested;

[0032] Measure the length and width of the cuboid-shaped sample to be tested with a steel ruler, and measure the thickness of the cuboid-shaped sample to be tested with a micrometer (measure the average value of the thickness multiple times), according to V 0 = length × width × thickness, calculate the apparent volume V of the sample to be tested 0 ;

[0033] 2) Place the sample to be tested in a blast drying oven at 60°C for 1 hour, then place it in a desiccator for natural cooling, put the sample to be tested in a real density meter, and measure the real volume. The...

Embodiment 2

[0036] Three lithium-ion battery ceramic separators with a thickness of about 20 μm, 18 μm and 16 μm were respectively selected, and the porosity data obtained by the test were shown in Table 1 according to the test method for the porosity of the lithium-ion battery ceramic separator in Example 1.

[0037] Table 1 Porosity of Li-ion battery ceramic separators with three different specifications

[0038]

[0039]

[0040] As can be seen from the data in the above table, the data error obtained by the test method of the porosity of lithium-ion battery ceramic diaphragm of the present invention is smaller, the data is more accurate, and the test process is simple, convenient and fast, and the requirements for equipment are relatively low. The inventive testing method for the porosity of the ceramic diaphragm is stable and reliable.

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Abstract

The invention relates to a test method for lithium ion battery ceramic diaphragm porosity and belongs to the field of lithium ion battery process material evaluation. The test method for the lithium ion battery ceramic diaphragm porosity provided by the invention comprises the following steps of testing apparent volume of a lithium ion battery ceramic diaphragm sample, and recording the apparent volume as V<0>; testing skeleton volume of the lithium ion battery ceramic diaphragm sample through application of an archimedes principle-gas expansion replacement method and recording the skeleton volume as V<1>; and computing porosity of the diaphragm according to the following formula: P=(V<0>-V<1>) / V<0>*100%. The test method for the lithium ion battery ceramic diaphragm porosity provided by the invention is simple in operation, low in test equipment and condition requirement, and high in operability. A process is easy to standardize and quantify. The porosity of the ceramic diaphragm can be tested relatively precisely.

Description

technical field [0001] The invention relates to a test method for the porosity of a lithium-ion battery ceramic diaphragm, belonging to the field of lithium-ion battery process material evaluation. Background technique [0002] Separator is an important part of lithium-ion battery, mainly plays the role of ion conduction and electronic insulation. The existing industrialized polyethylene or polypropylene separator cannot take into account the overall thickness, strength and porosity. The current charging and discharging performance is poor, which leads to a huge safety hazard in the application of power lithium batteries. In response to the lack of performance of the existing diaphragms, research institutions and enterprises in various countries are actively committed to the development of high-performance power lithium battery diaphragms. Among them, a layer of Al is coated on the surface of the diaphragm 2 o 3 , SiO 2 Or other heat-resistant inorganic ceramic particles...

Claims

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Application Information

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IPC IPC(8): G01N15/08
CPCG01N15/088
Inventor 许飞赵永锋陈芳杰李莉戚凤晓史瑞星席凯凯谭倩王宗葆冯营李明军
Owner DO FLUORIDE NEW ENERGY TECHNOLOGY CO LTD
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