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Method for testing rheological property of conductive slurry

A technology of rheological properties and testing methods, applied in the directions of flow properties, measuring devices, analytical materials, etc., can solve the problems of different, no testing fluid viscosity, inability to fluid thixotropic properties, etc. , the effect of comprehensive characterization

Inactive Publication Date: 2012-03-28
TRINA SOLAR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The test method A is to measure the apparent viscosity of the fluid. The disadvantage is that the test method A measures the apparent viscosity of the fluid at a single fixed speed, rather than the Newtonian fluid in the low shear, medium shear and high shear regions. The practical application significance of the characterization is different. The low-shear (quiescent state) region represents the storage performance of the fluid, the medium-shear region represents the stirring performance of the fluid, and the high-shear region represents the actual use performance of the fluid ( Such as the printing properties of pastes or the roll coating / spray coating properties of coatings), so test method A cannot fully characterize the rheological properties of non-Newtonian fluids
[0006] 1. TI index refers to the ratio of the viscosity of the fluid in the steady state at a shear rate that differs by 10 times. In the actual application of fluids, such as coatings, the shear rate is greater than 10 when spraying. 4 S -1 , the shear speed range is 10 when brushing / rolling 3 S -1 ~10 4 S -1 , while the leveling / sagging shear rate range is 10 -3 S -1 ~10 0 S -1 , so the shear rate with a difference of 10 times cannot be better used to characterize the thixotropic properties of the fluid;
[0007] 2. The TI index tests the viscosity from low shear to high shear fluid steady state, and does not test the fluid viscosity when returning from high shear rate to low shear rate. In the actual application of fluid, such as conductive paste After the material is screen-printed onto the battery sheet, the structure of the slurry will recover instantaneously, and it is necessary to provide test data of the viscosity of the slurry after printing when the viscosity returns to the initial low shear rate;
[0008] 3. The test method does not involve the test of the recovery time of the fluid structure when changing from high shear rate to low shear rate. In the actual application of fluid, for example, after the conductive paste is screen-printed on the cell, it is necessary to provide its structure instantaneous Response time, in order to improve the production efficiency into the next process
[0009] In summary, the current testing methods have obvious defects, and it is very important to find an accurate and comprehensive method to characterize the rheological properties of slurry

Method used

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  • Method for testing rheological property of conductive slurry
  • Method for testing rheological property of conductive slurry
  • Method for testing rheological property of conductive slurry

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Embodiment 1 - the test of apparent viscosity

[0049] 1. Calibrate the rheometer and set the test temperature to 25°C;

[0050] 2. According to the composition and initial viscosity of the conductive silver paste, select a cone-plate fixture with a diameter of 40mm, a cone angle of 1°, and a gap of 29um;

[0051] 3. For the cone-plate fixture, verify the system calibration factors on the air bearing friction coefficient, air bearing inertia, measurement system inertia, torque mapping and the zero point of the gap value Gap between the fixture and the bottom plate;

[0052] 4. Use a sample spoon to take the conductive silver paste and place it in the center of the base plate, lower the fixture by 30um, and set the descending speed when the fixture is 1cm away from the base to 100um·s -1 , Scrape the extruded sample with a rectangular wooden strip along the periphery of the fixture, and then lower the fixture to the inherent Gap 29um.

[0053] 5. After the sample is lo...

Embodiment 2

[0055] Embodiment 2—Thixotropic properties of shear-thinning fluid

[0056] 1. Calibrate the rheometer and set the test temperature to 25°C;

[0057] 2. According to the composition and initial viscosity of the conductive silver paste, select a cone-plate fixture with a diameter of 40mm, a cone angle of 1°, and a gap of 29um;

[0058] 3. For the cone-plate fixture, verify the system calibration factors on the air bearing friction coefficient, air bearing inertia, measurement system inertia, torque mapping and the zero point of the gap value Gap between the fixture and the bottom plate;

[0059] 4. Use a sample spoon to take the conductive silver paste and place it in the center of the base plate, lower the fixture by 30um, and set the descending speed when the fixture is 1cm away from the base to 100um·s -1 , Scrape the extruded sample with a rectangular wooden strip along the periphery of the fixture, and then lower the fixture to the inherent Gap 29um.

[0060] 5. After th...

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Abstract

The invention relates to the photovoltaic industry and in particular relates to a method for testing the rheological property of a conductive slurry. The method comprises the following steps: calibrating the instrument accuracy; setting a temperature; selecting and calibrating a clamp; loading and testing a sample; and determining the rheological property. Compared with a viscometer, the test method provided by the invention has a measurement accuracy which is one order of magnitude higher than that of the viscometer, needs a few samples, can be used for realizing accurate temperature control and quick experiment operations, and can represent the rheological property of the conductive slurry more comprehensively.

Description

technical field [0001] The invention relates to the photovoltaic industry, in particular to a method for testing the rheological properties of conductive paste. Background technique [0002] The conductive paste used in the photovoltaic industry is a fluid whose viscosity coefficient cannot remain constant when the shear rate changes. Measuring the rheological properties of the fluid mainly refers to measuring the viscosity and thixotropy of the fluid. Viscosity is a physical property of a fluid, which is used to measure the viscosity of the fluid. It is a physical parameter used in rheology to describe the resistance to shear-induced deformation; The rheological phenomenon, which characterizes the time-dependent properties of fluids, is a very important characteristic of coatings, food, cosmetics, pharmaceuticals and other important industrial products. [0003] At present, the rheological properties of the slurry are tested using the ASTM D2196 test standard, which includ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N11/00
Inventor 沈灿军赵冰王昭云周琳
Owner TRINA SOLAR CO LTD
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