A testing method for graphene thermal conductive film material

Abstract

The invention discloses a test method for a graphene thermal conductive film material, and relates to the technical field of graphene thermal conductive test. The method comprises the following steps: taking a contour center point as a heating point, performing a heating treatment on each graphene film under the same test environment, obtaining a thermal conductive parameter in combination with a heat transfer area analysis, obtaining a shape correlation coefficient according to the thermal conductive parameter and the shape complexity, outputting a thermal conductive parameter correction calculation formula according to the shape correlation coefficient, reflecting the intrinsic relationship between the thermal conductive parameter and the shape complexity and the influence on the thermal conductive test result by calculating the shape correlation coefficient, and contributing to a deeper understanding of the thermal conductive characteristics of the graphene film, introducing the shape correlation coefficient into a calculation formula of the thermal conductive parameter, performing correction processing, and correcting the calculation results of the thermal conductive parameters of films of different shapes according to the shape correlation coefficient, so as to reduce the test error caused by the irregular shape, and make the test result of the thermal conductive parameter of the graphene film more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of graphene thermal conductivity testing, in particular to a testing method for graphene thermal conductive film materials. Background Art

[0002] With the rapid development of science and technology, various electronic devices are becoming increasingly miniaturized and high-performance. During operation, a large amount of heat will inevitably be generated and accumulated. If the heat is not removed in time, it will affect the normal operation of the equipment and the stability of the system. In order to meet the needs of heat dissipation equipment, graphene film is used to remove the heat inside the equipment. Graphene film is light in weight, high in mechanical strength, and high in thermal conductivity. However, when applying graphene film, its thermal conductivity needs to be tested first to ensure that it can effectively conduct heat. The commonly used test method is to use precision testing instruments to test graphene film.

[0003] Patent publication number CN110887864A discloses a method for testing graphene thermally conductive film, including sampling of samples to be tested, creation of a test environment, placement of samples to be tested, placement of heating blocks, placement of temperature measuring components, collection of temperature data, acquisition of multiple sets of data, and analysis of temperature data. The method can accurately test the thermal conductivity of the graphene film and distinguish the performance differences of graphene films of different thicknesses. The method is simple to operate, less time consuming, and has high test efficiency, and is suitable for large-scale monitoring and testing.

[0004] However, the commonly used testing methods mainly rely on precise testing instruments. Although they can test the thermal conductivity of graphene films, they do not fully consider the influence of sample size and shape on the test results. In particular, the shape of the sample, such as whether the length and width are regular, has an important influence on the thermal conductivity test results. Based on this, a testing method for graphene thermal conductive film materials is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a testing method for graphene thermal conductive film materials, which solves the technical problem that the commonly used testing methods mainly rely on precise testing instruments. Although they can test the thermal conductivity of graphene films, they do not fully consider the influence of sample size and shape on the test results.

[0006] The testing method of graphene thermal conductive film material comprises the following steps:

[0007] Step 1: Obtaining contour edges of multiple graphene films with different shapes;

[0008] Step 2: According to the contour edge lines of each graphene film, the contour center points corresponding to each graphene film are obtained;

[0009] Step 3: According to the contour edge lines of each graphene film, the contour perimeters corresponding to each graphene film are obtained;

[0010] Step 4: According to the contour edge lines of each graphene film, the heat transfer area corresponding to each graphene film is obtained;

[0011] Step 5: Obtaining the shape complexity corresponding to each graphene film according to the contour perimeter and heat transfer area of ​​each graphene film;

[0012] Step 6: Under the same test environment, take the center point of the contour as the heating point, heat each graphene film, and obtain the thermal conductivity parameters in combination with the heat transfer area analysis;

[0013] Step 7: Analyze and obtain the shape correlation coefficient based on the thermal conductivity parameters and shape complexity;

[0014] Step 8: Output the thermal conductivity parameter correction calculation formula based on the shape correlation coefficient.

[0015] As a further solution of the present invention: the specific method of obtaining the contour center points corresponding to each graphene film is:

[0016] The coordinates of all shape points on the contour edge of each graphene film are obtained, and the average value of the horizontal coordinates of all shape point coordinates on the contour edge of each graphene film is used as the horizontal coordinate of the center point of each graphene film contour, and the average value of the vertical coordinates is used as the vertical coordinate of the center point of each graphene film contour, thereby obtaining the contour center point corresponding to each graphene film.

[0017] As a further solution of the present invention: the specific method of obtaining the contour perimeters corresponding to each graphene film is:

[0018] The distance between each two adjacent shape points on the contour line of each graphene film is calculated by using the coordinates of each two adjacent shape points, and the sum of the distances between each two adjacent shape points on the contour line of each graphene film is taken as the contour perimeter Ci corresponding to each graphene film, where i refers to different graphene films, i=1, 2,..., n, where n refers to the number of graphene films, n is a positive integer and n≥1.

[0019] As a further solution of the present invention: the specific method of obtaining the heat transfer area corresponding to each graphene film is:

[0020] According to the coordinates of all shape points on the contour edge of each graphene film, the length and width of each graphene film are obtained, the product b between the length and width of each graphene film is calculated, and b×θ is used as the heat transfer area Si corresponding to each graphene film, where θ is a preset parameter.

[0021] As a further solution of the present invention: the specific method of obtaining the length and width of each graphene film is:

[0022] From the coordinates of all shape points on the contour edge of each graphene film, the maximum and minimum values ​​corresponding to the horizontal and vertical coordinates on the contour edge of each graphene film are obtained, and the absolute value of the difference between the maximum and minimum values ​​of the horizontal coordinate of each graphene film is used as the length of each graphene film, and the absolute value of the difference between the maximum and minimum values ​​of the vertical coordinate of each graphene film is used as the width of each graphene film.

[0023] As a further solution of the present invention: the specific method of obtaining the shape complexity corresponding to each graphene film is:

[0024] The ratio EAi between the number of shape point coordinates mi on the contour edge of each graphene film and the contour perimeter Ci corresponding to each graphene film is obtained, and the ratio EBi to the heat transfer area Si is obtained, and the sum of EAi and EBi is taken as the shape complexity Hi corresponding to each graphene film.

[0025] As a further solution of the present invention: the specific method of obtaining the thermal conductivity parameters is:

[0026] Under the same test environment, the center point of the contour corresponding to each graphene film is used as the heating point, and each graphene film is heated by using a heating source under a predetermined heating power P, and the ratio between the predetermined heating power P and the heat transfer area Si corresponding to each graphene film is used as the heat flow Qi corresponding to each graphene film;

[0027] E temperature measurement points are set along the length and heat transfer direction of each graphene film, and the interval distance between each temperature measurement point is △x. The absolute value Ri of the difference between the maximum and minimum temperature values ​​at the e temperature measurement points of each graphene film is obtained. According to the formula Ki=(Qi×Di) / (Ri×Si), the thermal conductivity parameter Ki corresponding to each graphene film is calculated, △x is a preset value, e is a preset quantity value, e is a positive integer, and e>1.

[0028] As a further solution of the present invention: the specific method of analyzing and obtaining the shape correlation coefficient is:

[0029] The thermal conductivity parameters and shape complexity of multiple graphene films are combined into data sets (H1, K1), (H2, K2), ..., (Hn, Kn), and the average values ​​of shape complexity Hi and thermal conductivity parameter Ki are calculated. Then, the difference MAi between each shape complexity and the average shape complexity and the difference MBi between the thermal conductivity parameter and the average thermal conductivity parameter are calculated. The square sum GA of the shape complexity difference MAi and the square sum GB of the thermal conductivity parameter difference MBi are calculated. Then, the product sum L between the complexity difference MAi and the thermal conductivity parameter difference MBi is calculated. Finally, the formula , analyze and obtain the shape correlation coefficient Z.

[0030] As a further solution of the present invention: the specific method of outputting the thermal conductivity parameter correction calculation formula is:

[0031] Introduce the shape correlation coefficient into the formula Ki=(Qi×Di) / (Ri×Si) and output the thermal conductivity parameter correction calculation formula .

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention, by considering the shape complexity of the graphene film, can more accurately reflect the actual thermal conductivity of the film and reduce the test error caused by the irregular shape. The present invention not only tests the thermal conductivity parameters of the graphene film, but also introduces the shape correlation coefficient to evaluate the thermal conductivity of the film from multiple angles, so that the test results are more comprehensive and reliable, and the test method is applicable to graphene films of different sizes and shapes, providing a wider selection space for the application of graphene films in heat dissipation equipment.

[0034] At the same time, by calculating the shape correlation coefficient, the intrinsic relationship between the thermal conductivity parameters and the shape complexity is reflected, and the impact on the thermal conductivity test results is helpful to have a deeper understanding of the thermal conductivity characteristics of the graphene film. The shape correlation coefficient is introduced into the calculation formula of the thermal conductivity parameters for correction processing. The calculation results of the thermal conductivity parameters of films of different shapes are corrected according to the shape correlation coefficient to reduce the test error caused by irregular shape, making the test results of the thermal conductivity parameters of the graphene film more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the method flow structure of the present invention.

[0036] Figure 2 It is a schematic diagram of the process of obtaining the shape correlation coefficient of the present invention.

[0037] Figure 3 The figure is a flow chart of the output thermal conductivity parameter correction calculation formula of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1: Please refer to Figure 1-Figure 2 The present application provides a method for testing a graphene thermal conductive film material, comprising the following steps:

[0040] Step 1: Prepare multiple graphene films as samples to be tested. The multiple graphene films have different sizes and shapes. Perform shape scanning on each graphene film to obtain the contour edge lines corresponding to each graphene film. The specific method is as follows:

[0041] It should be noted that the graphene film can be scanned by an optical scanner, a three-dimensional scanner and other equipment to obtain an image of the graphene film, and then the acquired image is processed by denoising, enhancing and other processes to improve the image quality, and then an edge detection algorithm, such as the Canny edge detection algorithm, is used to detect the edge in the image to obtain the contour edge of the graphene film, and accurately determine the actual shape of the film, rather than relying solely on an assumed regular shape;

[0042] The above are existing and mature technologies, so no further elaboration is made here.

[0043] Step 2: Obtain the contour center points corresponding to each graphene film according to the contour edge lines corresponding to each graphene film, specifically in the following manner:

[0044] The coordinates of all shape points on the contour edge of each graphene film are obtained, and the average value of the horizontal coordinates of all shape point coordinates on the contour edge of each graphene film is used as the horizontal coordinate of the center point of the contour of each graphene film, and the average value of the vertical coordinates of all shape point coordinates on the contour edge of each graphene film is used as the vertical coordinate of the center point of the contour of each graphene film, thereby obtaining the contour center point corresponding to each graphene film, providing an accurate position for subsequent testing with this point as the heating point.

[0045] Step 3: Analyze the contour edges corresponding to each graphene film, and then obtain the contour perimeter corresponding to each graphene film. The specific method is as follows:

[0046] The distance between each two adjacent shape points on the contour edge of each graphene film is calculated through the coordinates of each two adjacent shape points on the contour edge of each graphene film, and the sum of the distances between each two adjacent shape points on the contour edge of each graphene film is taken as the contour perimeter Ci corresponding to each graphene film, where i refers to different graphene films, i=1, 2,..., n, where n refers to the number of graphene films, n is a positive integer and n≥1, and this parameter can reflect the influence of the complexity of the film shape on the boundary heat transfer.

[0047] Step 4: Analyze the contour edges corresponding to each graphene film, and then obtain the heat transfer area corresponding to each graphene film. The specific method is as follows:

[0048] From the coordinates of all shape points on the contour edge of each graphene film, the maximum and minimum values ​​corresponding to the horizontal and vertical coordinates on the contour edge of each graphene film are obtained, the absolute value of the difference between the maximum and minimum values ​​of the horizontal coordinate of each graphene film is used as the length of each graphene film, and the absolute value of the difference between the maximum and minimum values ​​of the vertical coordinate of each graphene film is used as the width of each graphene film; the product b between the length and width of each graphene film is obtained, and b×θ is used as the heat transfer area Si corresponding to each graphene film, where θ is a preset parameter. Taking into account the actual size differences of films of different shapes, it can more accurately reflect the effective area of ​​heat transfer. The specific value of the preset parameter θ is formulated by relevant personnel according to actual needs.

[0049] Step 5: Analyze the contour perimeter and heat transfer area corresponding to each graphene film, and then obtain the shape complexity corresponding to each graphene film. The specific method is as follows:

[0050] The ratio EAi of the number of shape point coordinates mi on the contour edge of each graphene film and the contour perimeter Ci corresponding to each graphene film is obtained, and at the same time, the ratio EBi of the number of shape point coordinates mi on the contour edge of each graphene film and the heat transfer area Si corresponding to each graphene film is obtained. The sum of EAi and EBi is taken as the shape complexity Hi corresponding to each graphene film. The performance of the film shape in terms of perimeter and area is comprehensively considered, and the irregularity of the film shape can be quantified.

[0051] Step 6: Under the same test environment, the contour center points corresponding to each graphene film are used as the corresponding heating points, and each graphene film is heated. Combined with the heat transfer areas corresponding to each graphene film, the heat conduction parameters corresponding to each graphene film are analyzed, and the specific method is as follows:

[0052] Obtaining a predetermined heating power P during the heating process, and using the ratio between the predetermined heating power P and the heat transfer area Si corresponding to each graphene film as the heat flow Qi corresponding to each graphene film;

[0053] Under the same test environment, heating is performed with the center point of the contour as the heating point. A heating source such as a laser, a resistance heater, etc. is used. e temperature measurement points are set along the length and heat transfer direction of each graphene film. The interval distance between each temperature measurement point is △x. A high-precision temperature sensor is used to measure the temperature value of each temperature measurement point, and the absolute value Ri of the difference between the maximum and minimum temperature values ​​in the e temperature measurement points of each graphene film is obtained. △x is a preset value. The specific value of △x is formulated by relevant personnel according to needs. e is a preset number value, e is a positive integer, and e>1;

[0054] The sample thickness Di corresponding to each graphene film is obtained, and the thermal conductivity parameter Ki corresponding to each graphene film is calculated according to the formula, Ki= (Qi×Di) / (Ri×Si).

[0055] Step 7: According to the thermal conductivity parameters and shape complexity corresponding to each graphene film, the shape correlation coefficient between the thermal conductivity parameters and shape complexity of the graphene film is analyzed. The specific method is as follows:

[0056] The thermal conductivity parameters and shape complexity of multiple graphene films are combined into data sets (H1, K1), (H2, K2), ..., (Hn, Kn);

[0057] First, the average values ​​of the shape complexity Hi and the thermal conductivity parameter Ki are calculated respectively, and then the difference MAi between each shape complexity and the average shape complexity and the difference MBi between the thermal conductivity parameter and the average thermal conductivity parameter are calculated;

[0058] Calculate the square sum GA of the shape complexity difference MAi and the square sum GB of the thermal conductivity parameter difference MBi, and then calculate the sum L of the products between the complexity difference MAi and the thermal conductivity parameter difference MBi;

[0059] Finally, the formula , the shape correlation coefficient Z between the thermal conductivity parameters and shape complexity of the graphene film is calculated;

[0060] The shape correlation coefficient Z between the thermal conductivity parameters and shape complexity of the graphene film is calculated. The thermal conductivity parameters and shape complexity of multiple graphene films are combined into a data set. The shape correlation coefficient Z is obtained through a series of calculations. This coefficient reflects the intrinsic connection between the thermal conductivity parameters and the shape complexity, and its influence on the thermal conductivity test results.

[0061] Use optical scanners or 3D scanners to scan the shape of the graphene film, extract the contour edge of the film through image processing technology, and calculate the contour center point. According to the contour edge, calculate the contour perimeter of the graphene film to reflect the complexity of its shape. At the same time, by analyzing the contour edge, determine the heat transfer area of ​​the film to more accurately reflect the effective area of ​​heat transfer. Combine the contour perimeter and the heat transfer area to calculate the shape complexity of the graphene film to quantify the irregularity of its shape. Under the same test environment, take the contour center point as the heating point to heat the graphene film, measure the temperature value with a high-precision temperature sensor, and calculate the thermal conductivity parameter in combination with the heat transfer area. According to the thermal conductivity parameter and shape complexity, analyze the shape correlation coefficient to reflect the intrinsic relationship between the thermal conductivity parameter and the shape complexity.

[0062] By performing shape scanning on the graphene film, analyzing the contour edges, calculating the contour center point, perimeter, heat transfer area and shape complexity, etc., the sample shape factor is fully considered, and the thermal conductivity can be tested more accurately. The performance of the film shape in terms of perimeter and area is comprehensively considered, and the influence of the irregularity of the film shape on thermal conductivity can be quantified. By calculating the shape correlation coefficient, the intrinsic connection between the thermal conductivity parameters and the shape complexity, and the influence on the thermal conductivity test results are reflected, which helps to gain a deeper understanding of the thermal conductivity characteristics of the graphene film.

[0063] Example 2: As Example 2 of the present invention, please refer to Figure 3 ,When the present application is implemented, compared with the embodiment 1, the technical solution of the present embodiment is different from the embodiment 1 only in that the present embodiment further includes step 8;

[0064] Step 8: Introduce the shape correlation coefficient into the calculation formula of the thermal conductivity parameter, correct the calculation of the thermal conductivity parameter of the graphene film, and output the thermal conductivity parameter correction calculation formula;

[0065] The thermal conductivity parameter correction calculation formula is as follows:

[0066] ;

[0067] The shape correlation coefficient is introduced into the calculation formula of thermal conductivity parameters, Ki=(Qi×Di) / (Ri×Si), and correction processing is performed. The calculation results of thermal conductivity parameters of films of different shapes are corrected according to the shape correlation coefficient to reduce the test error caused by irregular shape, making the test results of thermal conductivity parameters of graphene films more accurate.

[0068] Embodiment 3: As the embodiment 3 of the present invention, when the present application is implemented specifically, compared with the embodiments 1 and 2, the technical solution of this embodiment is to combine the solutions of the above-mentioned embodiments 1 and 2 for implementation.

[0069] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters and thresholds in the formula are set by technicians in this field according to actual conditions.

[0070] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for testing graphene thermal conductive film material, characterized in that: The following steps are involved: Step 1: Obtaining contour edges of multiple graphene films with different shapes; Step 2: According to the contour edge lines of each graphene film, the contour center points corresponding to each graphene film are obtained; Step 3: According to the contour edge lines of each graphene film, the contour perimeters corresponding to each graphene film are obtained; Step 4: According to the contour edge lines of each graphene film, the heat transfer area corresponding to each graphene film is obtained; The specific method of obtaining the heat transfer area corresponding to each graphene film is as follows: Obtain the coordinates of all shape points on the contour edge of each graphene film, and then obtain the length and width of each graphene film, calculate the product b between the length and width of each graphene film, and use b×θ as the heat transfer area Si corresponding to each graphene film, where θ is a preset parameter; The specific method for obtaining the length and width of each graphene film is: From the coordinates of all shape points on the contour edge of each graphene film, the maximum and minimum values ​​corresponding to the horizontal coordinate and the vertical coordinate on the contour edge of each graphene film are obtained, and the absolute value of the difference between the maximum and minimum values ​​of the horizontal coordinate of each graphene film is used as the length of each graphene film, and the absolute value of the difference between the maximum and minimum values ​​of the vertical coordinate of each graphene film is used as the width of each graphene film; Step 5: Obtaining the shape complexity corresponding to each graphene film according to the contour perimeter and heat transfer area of ​​each graphene film; The specific method for obtaining the shape complexity corresponding to each graphene film is: Obtain the ratio EAi between the number of shape point coordinates mi on the contour edge of each graphene film and the contour perimeter Ci corresponding to each graphene film, and at the same time obtain the ratio EBi to the heat transfer area Si, and use the sum of EAi and EBi as the shape complexity Hi corresponding to each graphene film; Step 6: Under the same test environment, take the center point of the contour as the heating point, heat each graphene film, and obtain the thermal conductivity parameters in combination with the heat transfer area analysis; The specific method of obtaining thermal conductivity parameters is: Under the same test environment, the center point of the contour corresponding to each graphene film is used as the heating point, and each graphene film is heated by using a heating source under a predetermined heating power P, and the ratio between the predetermined heating power P and the heat transfer area Si corresponding to each graphene film is used as the heat flow Qi corresponding to each graphene film; Set e temperature measurement points along the length and heat transfer direction of each graphene film, and the interval distance between each temperature measurement point is △x. Obtain the absolute value Ri of the difference between the maximum and minimum temperature values ​​in the e temperature measurement points of each graphene film, and obtain the sample thickness Di corresponding to each graphene film. According to the formula Ki=(Qi×Di) / (Ri×Si), calculate and obtain the thermal conductivity parameter Ki corresponding to each graphene film, △x is a preset value, e is a preset quantity value, e is a positive integer, and e>1; Step 7: Analyze and obtain the shape correlation coefficient based on the thermal conductivity parameters and shape complexity; The specific method of analyzing and obtaining the shape correlation coefficient is: The thermal conductivity parameters and shape complexity of multiple graphene films are combined into data sets (H1, K1), (H2, K2), ..., (Hn, Kn), and the average values ​​of shape complexity Hi and thermal conductivity parameter Ki are calculated. Then, the difference MAi between each shape complexity and the average shape complexity and the difference MBi between the thermal conductivity parameter and the average thermal conductivity parameter are calculated. The square sum GA of the shape complexity difference MAi and the square sum GB of the thermal conductivity parameter difference MBi are calculated. Then, the product sum L between the complexity difference MAi and the thermal conductivity parameter difference MBi is calculated. Finally, the formula , analyze and obtain the shape correlation coefficient Z; Step 8: Output the thermal conductivity parameter correction calculation formula based on the shape correlation coefficient.

2. A method for testing a graphene thermal conductive film material according to claim 1, characterized in that: The specific method of obtaining the contour center points corresponding to each graphene film is as follows: According to the coordinates of all shape points on the contour edge lines of each graphene film, the average value of the horizontal coordinates of all shape point coordinates on the contour edge lines of each graphene film is used as the horizontal coordinate of the center point of the contour of each graphene film, and the average value of the vertical coordinates is used as the vertical coordinate of the center point of the contour of each graphene film, thereby obtaining the contour center points corresponding to each graphene film.

3. The method for testing a graphene thermal conductive film material according to claim 1, characterized in that: The specific method for obtaining the contour perimeter corresponding to each graphene film is: The distance between each two adjacent shape points on the contour line of each graphene film is calculated by using the coordinates of each two adjacent shape points, and the sum of the distances between each two adjacent shape points on the contour line of each graphene film is taken as the contour perimeter Ci corresponding to each graphene film, where i refers to different graphene films, i=1, 2,..., n, where n refers to the number of graphene films, n is a positive integer and n≥1.

4. The method for testing a graphene thermal conductive film material according to claim 1, characterized in that: The specific method of outputting the thermal conductivity parameter correction calculation formula is: Introduce the shape correlation coefficient into the formula Ki=(Qi×Di) / (Ri×Si) and output the thermal conductivity parameter correction calculation formula .

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