Method for testing, characterizing and device for the ultimate charge carrying capacity

Abstract

The application discloses a kind of material limit charge carrying capacity test method, characterization method and device.The test method includes: applying test current or voltage to the material to be tested, gradually increases at preset current rise rate or preset voltage rise rate, until fuse;Obtain limit carrying current or voltage at multiple different rates;Based on the correlation, analyze the limit charge carrying capacity.The application first proposes the test or characterization method for evaluating the limit carrying capacity of the material at different current rise rates or voltage rise rates, and the obtained material test results can reflect the difference in limit carrying capacity at different rates, filling the gap in this field and providing test results with higher reference for application design;Firstly, the correlation characterization method using limit carrying capacity at different current rise rates or voltage rise rates and inherent characteristics of the material is proposed, which is a rapid and effective method for characterizing inherent characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material characterization testing, in particular to a test method and characterization method and device for limit charge carrying capacity. BACKGROUND

[0002] The development of materials provides a material basis for the development of science and technology, and the development of science and technology also puts forward higher requirements for the performance of materials. How to accurately and effectively test and evaluate the performance of materials in simulated or real application scenarios is particularly important for the practical application guidance and further research and development of materials.

[0003] Moreover, with the reduction in the size of devices in existing applications, the high performance and light weight of weapons and equipment, the size of the conductive circuit for powering them needs to be reduced by the same proportion, and the current density required by the circuit will increase significantly, which greatly increases the requirements for the limit carrying current or voltage capacity of the material.

[0004] Therefore, accurately reflecting the limit carrying capacity of the material under different conditions is crucial for the application design of the material. The prior art provides some test methods that change the test environment to test the carrying capacity of the material under different temperatures, pressures or atmospheres, but all ignore the influence of different current rise or voltage rise rates on the limit carrying capacity of the material. In actual application, the actual current rise or voltage rise rate faced by the material is usually different from that during testing, which also leads to the mismatch between testing and actual application, reducing the reference value of the test results.

[0005] In addition, the influence of different current rise or voltage rise rates on the limit carrying capacity of the material can further reflect some inherent properties of the material, and the prior art ignores this phenomenon, missing a quick and effective method for characterizing the inherent properties of the material. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a test method and characterization method and device for limit charge carrying capacity.

[0007] To achieve the foregoing application purposes, the technical solutions adopted by the present application include:

[0008] In a first aspect, the present application provides a test method for limit charge carrying capacity of a material, which includes:

[0009] applying a test current or a test voltage to the material to be tested, the test current gradually increasing at a preset current rise rate, and the test voltage gradually increasing at a preset voltage rise rate, until the material to be tested is fused;

[0010] obtaining the limit current carrying capacity or limit voltage carrying capacity of the material to be tested under a plurality of different preset current ramp-up rates or preset voltage ramp-up rates;

[0011] analyzing the limit charge carrying capacity of the material to be tested based on the correlation between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit current carrying capacity or limit voltage carrying capacity.

[0012] In a second aspect, the present application further provides a method for characterizing the properties of a material, which comprises:

[0013] applying a test current or test voltage to the material to be tested, the test current gradually increasing at a preset current ramp-up rate, and the test voltage gradually increasing at a preset voltage ramp-up rate, until the material to be tested is fused;

[0014] obtaining the limit current carrying capacity or limit voltage carrying capacity of the material to be tested under a plurality of different preset current ramp-up rates or preset voltage ramp-up rates;

[0015] analyzing the properties of the material to be tested based on the correlation between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit current carrying capacity or limit voltage carrying capacity.

[0016] In a third aspect, the present application further provides a device for testing the limit charge carrying capacity of a material, which comprises:

[0017] a test cavity for providing a test environment, at least one set of electrodes being arranged in the cavity, the electrodes being used for electrically connecting with the material to be tested;

[0018] a programmed power supply electrically connected with the electrodes, and used at least for applying a test current or test voltage to the material to be tested;

[0019] a detection unit used at least for monitoring the macroscopic morphology and / or temperature change of the material to be tested in the test environment.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The technical solution provided by the present application first proposes a method for testing or characterizing the limit charge carrying capacity of a material under different current or voltage ramp-up rates, and the obtained material test results can reflect the differences in the limit carrying capacity of the tested material under different current or voltage ramp-up rates, thereby filling the gap in this field and providing test results with higher reference value for the application design of materials.

[0022] The application first proposes a characterization method of the correlation between the ultimate current carrying capacity of materials under different current rise or voltage rise rates and the inherent properties of materials, which is a rapid and effective method for characterizing the inherent properties of materials and fills the gap in this field.

[0023] The above description is only a summary of the technical scheme of the application, in order to enable those skilled in the art to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, the following is the preferred embodiment of the application and the detailed description of the drawings as follows. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of a test device provided by a typical embodiment of the application;

[0025] Figure 2 is an interface schematic diagram of a test system provided by a typical embodiment of the application;

[0026] BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION

[0027] In view of the deficiencies in the prior art, the present inventors have long studied and practiced to propose the technical scheme of the present application. The technical scheme, its implementation process and principles will be further explained as follows.

[0028] In the following description, many specific details are set forth in order to provide a thorough understanding of the application, however, the application can also be implemented in other ways different from those described herein, therefore, the protection scope of the application is not limited by the specific embodiments disclosed below.

[0029] Moreover, the relationship terms such as "first" and "second" are only used to distinguish one from another with the same name of components or method steps, and do not necessarily require or imply any such actual relationship or order between the components or method steps.

[0030] In order to fill the gap of the existing test and characterization methods, the purpose of the present application is to propose a test device and test method for the ultimate current carrying capacity of materials, which realizes the on-demand output of the test current or voltage rise rate by interconnecting the test software and the programmable power supply, and at the same time, analyzes and evaluates the current carrying capacity of materials in different application environments simulated by the test device.

[0031] In order to achieve the above purpose, one aspect of an embodiment of the present application provides a test method for the ultimate current carrying capacity of materials, which includes the following steps:

[0032] applying a test current or a test voltage to the material to be tested, the test current gradually increasing at a preset current ramp-up rate, and the test voltage gradually increasing at a preset voltage ramp-up rate, until the material to be tested is fused.

[0033] obtaining a limit current carrying capacity or a limit voltage carrying capacity of the material to be tested at a plurality of different preset current ramp-up rates or preset voltage ramp-up rates.

[0034] analyzing the limit charge carrying capacity of the material to be tested based on a correlation between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit current carrying capacity or the limit voltage carrying capacity.

[0035] Based on the above technical solutions, the present application is first based on the law discovered by the inventor, i.e. under different current ramp-up rates or voltage ramp-up rates, the limit carrying capacity of the material itself is not constant, but changes regularly and obviously with the change of the current ramp-up rate or the voltage ramp-up rate, and the limit carrying capacity under different current ramp-up rates or voltage ramp-up rates can differ by several times. Such a difference easily leads to the fact that the existing test methods cannot accurately reflect how much current / voltage the material can withstand in a specific application scenario. The above technical solutions utilize the phenomenon and law discovered by the present application, and objectively reflect the influence of different current ramp-up rates or voltage ramp-up rates on the limit carrying capacity through multi-point testing, for example, a standard curve of rate-carrying capacity can be provided. In a specific application design, the designer can refer to the curve and the current ramp-up rate of the material to be tested under the target application scenario to accurately define the design limit, and provide a very referenceable test result.

[0036] In some embodiments, when the preset current ramp-up rate is below a first threshold and / or the preset voltage ramp-up rate is below a second threshold, the limit current carrying capacity is positively correlated with the preset current ramp-up rate, and / or the limit voltage carrying capacity is positively correlated with the preset voltage ramp-up rate.

[0037] When the preset current ramp-up rate is above the first threshold and / or the preset voltage ramp-up rate is above the second threshold, the limit current carrying capacity is negatively correlated with the preset current ramp-up rate, and / or the limit voltage carrying capacity is negatively correlated with the preset voltage ramp-up rate.

[0038] In some embodiments, the test method further comprises recording the highest temperature when the material to be tested is fused.

[0039] In some embodiments, the material to be tested is tested under selected environmental conditions, the selected environmental conditions including any one or a combination of two or more of a protective atmosphere, a vacuum degree, an oxidizing atmosphere, a reducing atmosphere, humidity, and an ambient temperature.

[0040] In some embodiments, the limit charge carrying capability includes a current rise rate corresponding to the first threshold, and / or a voltage rise rate corresponding to the second threshold.

[0041] In some embodiments, the limit charge carrying capability further includes a limit carrying current value corresponding to the first threshold, and / or a limit carrying voltage value corresponding to the second threshold.

[0042] As some typical application examples of the above technical solutions, a specific experimental case of the present application is, for example, as follows: using the experimental device shown in Figure 1 and the test system shown in Figure 2 the starting current and the ending current of the test are input, and the current rise rate or the voltage rise rate is set. For example, the voltage rise rates are set as 100 V / s, 400 V / s, 800 V / s, 1200 V / s, and 1600 V / s in sequence, and the limit current carrying capability of the material under different voltage rise rates is tested. During the test, the system automatically records the limit carrying current value, the limit carrying voltage value, the highest temperature when the material is fused, and the time length of the material under the current, and draws the relevant I / T, I / V, I / t, V / T, and other relationship curves. Researchers can comprehensively evaluate the subsequent work in combination with the relationship curves, test data, and macroscopic morphology.

[0043] The second aspect of the embodiment of the present application further provides a material characteristic representation method, which includes:

[0044] A test current or a test voltage is applied to the material to be tested, the test current gradually increases at a preset current rise rate, and the test voltage gradually increases at a preset voltage rise rate, until the material to be tested is fused.

[0045] The limit carrying current or the limit carrying voltage of the material to be tested corresponding to a plurality of different preset current rise rates or preset voltage rise rates is obtained.

[0046] Based on the correlation between the plurality of preset current rise rates or preset voltage rise rates and the limit carrying current or the limit carrying voltage, the characteristics of the material to be tested are analyzed.

[0047] In some embodiments, the inherent characteristics include any one or a combination of the above of the defect density, the crystallinity, and the micro-orientation of the material to be tested.

[0048] The inventors of the present application have also found a correlation between the above-mentioned correlation and the inherent properties of the material. For the same material, for example, carbon fiber, when the microstructure inside the material is different, for example, the degree of crystallinity is different, or the orientation is different, it will also cause the relationship curve between the ultimate bearing capacity and the current or voltage rise rate of the same carbon fiber material to change. Using this rule, various technical means can be developed to qualitatively or even quantitatively characterize the inherent properties of the material using the above-mentioned phenomenon.

[0049] For example, in some embodiments, the characterization method can specifically include:

[0050] The first threshold value corresponding to the inflection point of the ultimate bearing current and / or the second threshold value corresponding to the inflection point of the ultimate bearing voltage is obtained through the correlation curve of the plurality of preset current rise rates or preset voltage rise rates and the ultimate bearing current or ultimate bearing voltage.

[0051] The defect density is negatively correlated with the first threshold value and / or the second threshold value; and / or, the degree of crystallinity is positively correlated with the first threshold value and / or the second threshold value; and / or, the micro-orientation is positively correlated with the first threshold value and / or the second threshold value.

[0052] In some embodiments, the characterization method can further include: obtaining the maximum ultimate bearing current value or the maximum ultimate bearing voltage value through the correlation curve.

[0053] The defect density is negatively correlated with the maximum ultimate bearing current value and / or the maximum ultimate bearing voltage value; and / or, the degree of crystallinity is positively correlated with the maximum ultimate bearing current value and / or the maximum ultimate bearing voltage value; and / or, the micro-orientation is positively correlated with the maximum ultimate bearing current value and / or the maximum ultimate bearing voltage value.

[0054] Referring to Figure 1 and Figure 2 , the present application also provides a test device for the ultimate charge bearing capacity of a material, which comprises:

[0055] a cavity 1 for accommodating the material to be tested, at least one set of electrodes being arranged in the cavity 1, the electrodes being capable of being electrically connected with the material to be tested.

[0056] a programmed power supply electrically connected with the electrodes for applying controllable current and / or voltage.

[0057] and an observation unit arranged on the cavity 1 for observing the macroscopic morphology and / or temperature change of the material to be tested.

[0058] As some typical application examples of the above technical solutions, the device main body part of the test device comprises a test cavity 1, a programmable power supply, and an auxiliary device part.

[0059] Wherein:

[0060] Cavity 1 part: can realize vacuum, protective atmosphere and other test environment, for evaluating the current-carrying performance of materials under different environmental atmosphere.

[0061] Programmable power supply part: through the interconnection of software and programmable power supply, the setting of different current rising speed or voltage rising speed is realized, and the current-carrying capacity of materials under different current rising or voltage rising speed is evaluated.

[0062] Auxiliary device part: mainly includes infrared temperature measuring device, used for recording the temperature change of materials in the test; high-speed camera device, used for recording the macroscopic morphology change of materials in the test; water chiller device, used for providing cooling circulating water, assisting the cooling protection of test connecting cable and terminal post 10.

[0063] In some embodiments, the cavity 1 is a closed structure, and a gas passage is further arranged on the cavity wall, which is used for conveying gas or vacuumizing into the cavity 1.

[0064] In some embodiments, the electrodes are arranged in multiple groups.

[0065] In some embodiments, the multiple groups of electrodes are arranged in sequence along a specified direction.

[0066] In some embodiments, the device can further comprise a water cooling unit connected with the electrodes and the cable between the electrodes and the programmable power supply 9 through a cooling pipeline, which is used for cooling the electrodes and the cable.

[0067] As some typical application examples of the above technical solutions, a specific test device is shown in Figure 1 The device comprises a main body part of a test cavity 1 of the device; an exhaust valve 2 arranged on the wall of the cavity 1, used for exhausting the cavity 1 to break the vacuum; an infrared thermometer 3 arranged on the cavity 1, used for testing and recording the real-time temperature of materials in the current-carrying test; a material current-carrying test sample connecting terminal 4, equivalent to an electrode, arranged in the cavity 1, used for electrically contacting with the materials to be tested; a gas input valve 5 arranged on the wall of the cavity 1, which can selectively input nitrogen, argon or other protective gas into the test cavity 1 to achieve the related environmental test atmosphere; a high-speed camera 6 arranged on the cavity 1, used for recording the macroscopic morphology change of materials in the test; a vacuumizing valve 7 arranged on the wall of the cavity 1, connected with a mechanical pump and a molecular pump, and the final vacuum degree is ≤9.0×10 -5Pa, exhaust valve 2, vacuumizing valve 7 and gas input valve 5 constitute a gas passage together; water-cooled cable 8 connects terminal post 10 on test cavity 1 with programmed power supply 9 for supplying power to test material; programmed power supply 9, through interconnection with control software, can realize test of current supply according to set voltage rising speed or current rising speed, evaluate limit current carrying capacity of material under different voltage rising or current rising speed; material current carrying test terminal post 10, electrically connected with terminal 4 and water-cooled cable 8, this terminal post 10 can be provided with multiple groups in test cavity 1 so as to simultaneously carry out multiple group comparison experiments.

[0068] The technical solutions of the present application are further described in detail below by means of several embodiments in combination with the drawings. However, the selected embodiments are only used to illustrate the present application and do not limit the scope of the present application.

[0069] Embodiment 1

[0070] This embodiment shows a test process of limit charge carrying capacity of carbon nanotube fiber, as shown below:

[0071] Using carbon nanotube fiber as test material, set starting current as 0A and ending current as upper limit value of power supply output. Perform limit current carrying capacity test of material under different current rising speed, and test results are shown in the following table:

[0072]

[0073] From the test data, it can be concluded that the same sample shows different limit current carrying capacity under different current rising speed, and the maximum and minimum can form a difference of nearly 5 times, combined with other performance parameters recorded by the test system, which is helpful for guiding further research.

[0074] It can be seen that with the increase of current rising speed, the limit current carrying value will first increase and then decrease, and the threshold value corresponding to the inflection point and the maximum carrying current value are important comprehensive indicators that comprehensively reflect the carrying capacity of the material.

[0075] For example, in the application design of the material, if the current rising speed is 100-500A / s, the current should be limited to below 3A, and if the current rising speed is 1300-1700A / s, the maximum current should be limited to 8A.

[0076] Or, in the design of the device, the current rising speed of the carbon nanotube wire is controlled as much as possible between 1300-1700A / s, so as to obtain the best overcurrent resistance.

[0077] Embodiment 2

[0078] The embodiment example shows a process of characterizing the orientation degree of carbon nanotube fibers, and specifically as follows:

[0079] In the preparation process of carbon nanotube fibers, by controlling the stretching rate, various orientation degrees of carbon nanotube fibers are obtained, and by the same test method of embodiment 1, it is found that the curve inflection point current rise rate and the maximum current value corresponding to the carbon nanotube fibers of different orientation degrees are different.

[0080] The basic rule is that at the corresponding current rise rate, the better the orientation degree, the greater the maximum current value.

[0081] Therefore, the embodiment establishes a method for characterizing the orientation degree of carbon nanotube fibers. Without relying on polarized Raman spectroscopy, by testing the change of the ultimate current value at different current rise rates, the orientation degree of the carbon nanotube fibers can be reflected to some extent.

[0082] Embodiment 3

[0083] The embodiment example shows a process of testing the ultimate charge carrying capacity of carbon fibers, and specifically as follows:

[0084] 1k carbon fibers are used as test materials, the starting current is set to 0A, and the end current is set to the upper limit value of the power supply output. Different current rise rates are used to test the ultimate current carrying capacity of the materials, and the test results are shown in the following table:

[0085]

[0086]

[0087] Embodiment 4

[0088] The embodiment example shows a process of characterizing the crystallinity of carbon nanotube fibers, and specifically as follows:

[0089] In the preparation process of carbon nanotube fibers, different fibers will show good and bad performance due to the influence of various parameters. It is particularly important to quickly and effectively judge the performance of the fibers to guide the confirmation of process parameters and production. By the same test method of embodiment 1, it is found that the maximum current value of carbon nanotube fibers of different crystallinity is different at the corresponding current rise rate.

[0090] The basic rule is that at the corresponding current rise rate, the better the crystallinity, the greater the maximum current value. This method can quickly and effectively judge the crystallinity of the materials, avoid excessive and tedious high-cost tests such as XRD tests, and fill the gap of low-cost crystallinity test of carbon nanotube fibers.

[0091] Based on the above embodiments, it can be clear that the technical solutions provided by the embodiments of the present application first propose a test or characterization method for evaluating the limit charge carrying capacity of a material under different current rise or voltage rise rates, the obtained material test results can reflect the difference in the limit carrying capacity of the tested material under different current rise or voltage rise rates, and the blank in the field is filled, and the test results with higher reference for the application design of the material are provided.

[0092] The embodiments of the present application first propose a correlation characterization method for the limit carrying capacity of a material under different current rise or voltage rise rates and the inherent characteristics of the material, which belongs to a rapid and effective method for characterizing the inherent characteristics of a material, and also fills the blank in the field.

[0093] It should be understood that the above embodiments are only for illustrating the technical concepts and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A method of testing the ultimate charge carrying capacity of a material, characterized by, The method comprises: applying a test current or a test voltage to a material to be tested, the test current gradually increasing at a preset current ramp-up rate, and the test voltage gradually increasing at a preset voltage ramp-up rate, until the material to be tested is fused, and recording the highest temperature at which the material to be tested is fused; the material to be tested is tested under selected environmental conditions, the selected environmental conditions including any one or a combination of more than two of a protective atmosphere, a vacuum degree, an oxidizing atmosphere, a reducing atmosphere, humidity, and an ambient temperature; obtaining a limit carrying current or a limit carrying voltage of the material to be tested corresponding to a plurality of different preset current ramp-up rates or preset voltage ramp-up rates, the limit carrying current being positively correlated with the preset current ramp-up rate when the preset current ramp-up rate is below a first threshold, and the limit carrying voltage being positively correlated with the preset voltage ramp-up rate when the preset voltage ramp-up rate is below a second threshold; when the preset current ramp-up rate is above the first threshold or the preset voltage ramp-up rate is above the second threshold, the limit carrying current is negatively correlated with the preset current ramp-up rate, or the limit carrying voltage is negatively correlated with the preset voltage ramp-up rate; based on the correlation between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit carrying current or limit carrying voltage, analyzing the limit charge carrying capacity of the material to be tested, the limit charge carrying capacity including the current ramp-up rate corresponding to the first threshold, or the voltage ramp-up rate corresponding to the second threshold, and further including the limit carrying current value corresponding to the first threshold, or the limit carrying voltage value corresponding to the second threshold.

2. The test method of claim 1, wherein, Specifically, the method comprises: based on the correlation between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit carrying current or limit carrying voltage, analyzing the characteristics of the material to be tested, the material characteristics including any one or a combination of more than two of a crystallinity of the material to be tested and a micro-orientation of the material to be tested.

3. The test method of claim 2, wherein, Specifically, the method comprises: obtaining, through the correlation curve between the plurality of preset current ramp-up rates or preset voltage ramp-up rates and the limit carrying current or limit carrying voltage, the first threshold corresponding to an inflection point of the limit carrying current, or the second threshold corresponding to an inflection point of the limit carrying voltage; the crystallinity is positively correlated with the first threshold or the second threshold; and the micro-orientation is positively correlated with the first threshold or the second threshold.

4. The test method of claim 3, wherein, Further, the method comprises: obtaining, through the correlation curve, a maximum limit carrying current value or a maximum limit carrying voltage value, the crystallinity being positively correlated with the maximum limit carrying current value or the maximum limit carrying voltage value; the micro-orientation being positively correlated with the maximum limit carrying current value and / or the maximum limit carrying voltage value.

5. The test method of claim 1, wherein, The test device used for testing the limit charge carrying capacity of the material in the test method comprises: a test cavity for providing a test environment, at least one set of electrodes being arranged in the cavity, the electrodes being used for electrical connection with a material to be tested; a programmed power supply electrically connected with the electrodes, and used at least for applying a test current or a test voltage to the material to be tested. The detection unit is used for monitoring at least macro appearance and / or temperature change of the material to be tested in the test environment.

6. The test device of claim 5, wherein, The test cavity is a closed structure, and a gas passage is further arranged on the cavity wall, which is used for at least conveying gas into the cavity or vacuumizing the cavity to change the test environment. The electrodes are arranged in multiple groups, and the multiple groups of electrodes are arranged in sequence along a specified direction.

7. The test device of claim 5, wherein, A water cooling unit is further included, which is connected with the electrodes and cables between the electrodes and the programmed power supply through a cooling pipeline, and is used for cooling the electrodes and the cables.

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