Multi-channel resistivity testing apparatus and method

Abstract

A multi-channel resistivity testing apparatus, comprising a power supply (1) and a current measurement module (2), wherein one electrode of the power supply (1) is provided with a first main probe (7), and the other electrode of the power supply (1) is provided with a second main probe (8); the first main probe (7) is applied to the upper end surface (61) of a resistor cylinder (6) and is electrically connected to the resistor cylinder (6); the second main probe (8) is applied to the lower end surface (62) of the resistor cylinder (6) and is electrically connected to the resistor cylinder (6); the side wall of the resistor cylinder (6) is provided with voltage measurement probes Ti, wherein i is equal to 1, 2, ..., or n. According to the multi-channel resistivity testing apparatus, compared with a traditional two-probe-based testing method, a voltage measurement position is changed into the side wall, and the influence of the contact resistance and the resistance of the electrodes is eliminated. Because the distance between the probes is known, a thickness measurement apparatus is not required, and multiple sections of resistivity data can be obtained by one-time testing, thereby improving the efficiency.

Description

Multi-channel resistivity testing device and method Technical Field

[0001] The present invention relates to a resistivity testing device, more specifically, to a multi-channel resistivity testing device and method. Background Art

[0002] Existing powder materials are widely used in composite materials due to their advantages, including high electrical and thermal conductivity, low density, and ease of processing and molding. However, the resistivity of some powders significantly influences the electrical conductivity of composite materials, making accurate evaluation of powder conductivity crucial. However, current mainstream measurement methods struggle to accurately measure the resistivity of powder samples.

[0003] Figure 1 illustrates the existing two-probe measurement method. Two test electrodes 300 are placed at either end of a sample 200. A current is applied to the sample 200 and the voltage is measured to determine the overall resistance R. Simultaneously, a displacement sensor measures the thickness l of the sample 200. Given the probe area S, the resistivity is calculated using the formula ρ = RS / l. A disadvantage of this two-probe measurement method is that the measured resistance includes the contact resistance between the electrodes and the sample, as well as the resistance of the electrodes themselves.

[0004] Figure 2 illustrates the existing four-probe measurement method. Four test electrodes 500 are placed on the same side of the sample 200 being tested. The outer two electrodes apply current to the sample, while the inner two electrodes detect the voltage to obtain resistance R0. Simultaneously, a displacement sensor measures the thickness l. The probe coefficient k is calculated based on the electrode spacing d and the powder thickness l. The overall resistance R1 = k*R0, and the resistivity is calculated using the formula ρ = R1S / l. A disadvantage of this four-probe measurement method is the nonlinear distribution of current in the test sample, making calculation of the probe coefficient complex. Summary of the Invention

[0005] Based on this, it is necessary to provide a multi-channel resistivity testing device and method to address the above technical problems.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A multi-channel resistivity testing device, characterized in that the multi-channel resistivity testing device includes a power supply and a current detection module, one pole of the power supply is provided with a first main probe, the other pole of the power supply is provided with a second main probe, the first main probe is applied to the upper end surface of the resistor column and forms an electrical connection with the resistor column, the second main probe is applied to the lower end surface of the resistor column and forms an electrical connection with the resistor column,

[0008] As a preferred embodiment, a voltage detection probe T is provided on the side wall of the resistor column.i , the voltage detection probe T i Through the voltage detection switch K i Form an electrical connection with a voltage detection module, wherein, i=1, 2, 3, ..., n.

[0009] As a preferred embodiment, the voltage detection probe T i A temperature sensor S is provided on one side of the i , the temperature sensor S i Detect the voltage detection probe T i The temperature of the temperature sensor S i Form an electrical connection with a temperature detection module, wherein i=1, 2, 3, ..., n.

[0010] As a preferred embodiment, a first switch is provided between the voltage detection module and the upper end surface of the resistor column, and a second switch is provided between the voltage detection module and the lower end surface of the resistor column.

[0011] As a preferred embodiment, the resistor column is a columnar compressed body obtained by compressing solid powder.

[0012] As a preferred embodiment, the resistor column is a mixture of solid powder and liquid.

[0013] As a preferred embodiment, the power supply is an adjustable power supply.

[0014] As a preferred embodiment, the voltage detection probe T i It is needle-shaped, where i=1,2,…,n.

[0015] As a preferred embodiment, the voltage detection probe T i It is in the shape of a ring, where i=1,2,…,n.

[0016] A method for measuring resistivity using the multi-channel resistivity testing device as described above comprises the steps of:

[0017] Step S1: placing a resistor column to be tested on an insulating jig and applying pressure to the resistor column;

[0018] Step S2: Turn on the power supply, apply a preliminary detection current I0 to the first main probe and the second main probe, close the first switch and the second switch, and the voltage detection module detects a preliminary detection voltage U0 between the first main probe and the second main probe, and obtains a preliminary detection resistance value R0 of the resistor column = U0 / I0;

[0019] Step S3: Adjust the voltage of the power supply according to the initial resistance value R0 of the resistor column and heat the resistor column until the temperature detection module detects that the temperature sensor S i All reach the preset temperature T e , where i=1,2,…,n;

[0020] Step S4: Close the voltage detection switch K i Any two of the above, the voltage detection module detects a voltage U between the two voltage detection probes, and the current detection module detects a current I, where i=1, 2, ..., n;

[0021] Step S5, calculating the resistance R=U / I between the two voltage detection probes;

[0022] Step S6: Calculate the resistivity ρ0=R*S / l, where S is the cross-sectional area of ​​the resistor column, and l is the distance between the two voltage detection probes.

[0023] As a preferred embodiment, the resistor column is a columnar compressed body obtained by compressing solid powder, or a mixture of solid powder and liquid.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a multi-channel resistivity testing device and method. Compared to traditional two-probe testing methods, this multi-channel resistivity testing device shifts the voltage detection location to the sidewall, eliminating the influence of contact resistance and the electrode's own resistance. Because the distance between the probes is known, a thickness detection device is not required. The device can test the resistivity of multiple powder sections, improving testing efficiency and verifying whether the powder is uniformly compressed. Furthermore, during the test, the powder's own heat generation eliminates the effects of moisture, further improving test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the solutions in the present invention, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] FIG1 is a schematic structural diagram of an existing multi-channel resistivity test device, which adopts a two-probe test method;

[0028] FIG2 is a schematic structural diagram of an existing multi-channel resistivity test device, which uses a four-probe test method;

[0029] FIG3 is a schematic structural diagram of a multi-channel resistivity testing device according to the present invention;

[0030] FIG4 is a schematic structural diagram of a voltage detection probe of the multi-channel resistivity test device in FIG2 ;

[0031] FIG5 is a schematic structural diagram of another embodiment of the voltage detection probe in FIG4 ;

[0032] FIG6 is a test schematic diagram of a multi-channel resistivity test device according to the present invention, in which the number of voltage detection probes is four;

[0033] FIG7 is a partial view of the test schematic diagram in FIG6 ;

[0034] FIG8 is a linear fitting diagram of the test results of the multi-channel resistivity test device in FIG6 . Implementation Method

[0035] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0036] As shown in FIG3 , the multi-channel resistivity test device includes a power supply 1 and a current detection module 2. One pole of the power supply 1 is provided with a first main probe 7, and the other pole of the power supply 1 is provided with a second main probe 8. The first main probe 7 is applied to the upper end surface 61 of the resistor column 6 and forms an electrical connection with the resistor column 6. The second main probe 8 is applied to the lower end surface 62 of the resistor column 6 and forms an electrical connection with the resistor column 6.

[0037] The side wall of the resistor column 6 is provided with a voltage detection probe T i , the voltage detection probe T i Through the voltage detection switch K i Form an electrical connection with a voltage detection module 3, wherein, i=1, 2, 3, ..., n.

[0038] The voltage detection probe T i A temperature sensor S is provided on one side of the i , the temperature sensor S i Detect the voltage detection probe T i The temperature of the temperature sensor S i Form an electrical connection with a temperature detection module 4, wherein i=1, 2, 3, ..., n.

[0039] A first switch 31 is provided between the voltage detection module 3 and the upper end surface 61 of the resistor column 6 , and a second switch 32 is provided between the voltage detection module 3 and the lower end surface of the resistor column 6 .

[0040] It should be noted that the resistor column 6 is a columnar compressed body obtained by compressing solid powder, or the resistor column 6 is a mixture of solid powder and liquid.

[0041] In addition, the resistor column 6 mentioned here can be either a column of equal diameter or a column of variable diameter.

[0042] The following describes a method for measuring resistivity using a multi-channel resistivity test device, including the following steps:

[0043] Step S1: placing the resistor column 6 to be tested on the insulating fixture 9 and applying pressure to the resistor column 6;

[0044] Step S2: Turn on the power supply 1, apply a preliminary detection current I0 to the first main probe 7 and the second main probe 8, close the first switch 31 and the second switch 32, and the voltage detection module 3 detects a preliminary detection voltage U0 between the first main probe 7 and the second main probe 8, and obtains a preliminary detection resistance value R0 = U0 / I0 of the resistor column 6;

[0045] Step S3, adjust the voltage of the power supply 1 according to the initial detection resistance value R0 of the resistor column 6, and heat the resistor column 6 until the temperature detection module 4 detects that the temperature sensor S i All reach the preset temperature T e , where i=1,2,…,n;

[0046] Step S4: Close the voltage detection switch K i Any two of the above, the voltage detection module 3 detects the voltage U between the two voltage detection probes, and the current detection module 2 detects the current I, where i=1, 2, ..., n;

[0047] Step S5, calculating the resistance R=U / I between the two voltage detection probes;

[0048] Step S6: Calculate the resistivity ρ0=R*S / l, where S is the cross-sectional area of ​​the resistor column 6 and l is the distance between the two voltage detection probes.

[0049] It should be noted that the power supply 1 is an adjustable power supply that can adjust the voltage across the resistor column 6. Furthermore, it should be noted that the power supply 1 is an adjustable power supply that can be an adjustable voltage source that adjusts the voltage across the resistor column 6 or an adjustable current source that adjusts the current flowing through the resistor column 6.

[0050] As shown in FIG4 , the voltage detection probe T i It is needle-shaped, where i=1,2,…,n.

[0051] As shown in FIG5 , the voltage detection probe T i In another embodiment, the voltage detection probe T i It is in the shape of a ring, where i=1,2,...,n. It should be noted that the voltage detection probe T i The shape may also be other shapes as long as voltage collection is achieved at different heights.

[0052] The testing method of the multi-channel resistivity testing device is described below.

[0053] The following takes n=4 as an example for further explanation.

[0054] As shown in Figures 6 and 7, the preset distance D1 between the voltage detection probe T1 and the lower end surface 62 of the resistor column 6 is 0.5MM, the preset distance D2 between the voltage detection probe T2 and the lower end surface 62 of the resistor column 6 is 3.5MM, the preset distance D3 between the voltage detection probe T3 and the lower end surface 62 of the resistor column 6 is 7.5MM, and the preset distance D4 between the voltage detection probe T4 and the lower end surface 62 of the resistor column 6 is 10.5MM. The diameter of the resistor column 6 is 13MM. At this time, the cross-sectional area S of the resistor column 6 is π*0.065*0.065M 2 .

[0055] At this time, the power supply 1 applies voltage, the current detection module 2 detects a preliminary detection current I0 = 100 mA, closes the first switch 31 and the second switch 32, and the voltage detection module 3 detects a preliminary detection voltage U0 = 6.037 V between the first main probe 7 and the second main probe 8, thereby obtaining a preliminary detection resistance value R0 = U0 / I0 = 6.037 / 0.1Ω = 60.37Ω of the resistor column 6.

[0056] At this time, the power generated by the resistor column 6 is P0=I0*U0=0.6037W. The power supply 1 is adjusted so that the current detected by the current detection module 2 reaches I1=500mA. The heating power of the resistor column 6 is P1=I1^2*R0=0.5^2*60.37W=15.0925W. The resistor column 6 is heated and the temperature detection module 4 is observed until the temperature detection module 4 detects that all temperature sensors S have reached the preset temperature T. e , at this time, T e =200°. This preset temperature T e It is related to the material of the resistor column 6.

[0057] Then, the voltage detection switch K1 and the voltage detection switch K2 are closed, and the voltage detection module 3 detects the voltage U between the voltage detection switch K1 and the voltage detection switch K2. 21 =1.5951V, at this time, the distance between the voltage detection probe T2 and the voltage detection probe T1 is l21 =D2-D1=(3.5-0.5)MM=3MM, the resistance R between the voltage detection switch K1 and the voltage detection switch K2 21 =U 21 / I 21 =1.5951 / 0.1=15.951Ω, so,

[0058] Resistivity ρ0=R*S / l 21 =15.951*π*0.065*0.065 / 0.03Ω / m=0.705738Ω / m.

[0059] In the same way, the voltage detection switch K1 and the voltage detection switch K2 are closed, the voltage detection switch K1 and the voltage detection switch K3 are closed, and the voltage detection switch K1 and the voltage detection switch K4 are closed. The test results are shown in Table 1 below.

[0060] Table 1 Resistivity test results

[0061] As shown in FIG8 , the test results in Table 1 are linearly fitted. The intersection of the curve and the y-axis at 0.1866 V represents the contact resistance and the voltage drop generated by the electrode. The resistance of this part is 0.1866 V / 100 mA = 1.866 Ω.

[0062] Compared to traditional two-probe testing methods, this multi-channel resistivity tester shifts the voltage detection location to the sidewall, eliminating the influence of contact resistance and the electrode's own resistance. Because the distance between the probes is known, a thickness detector is not required. This allows the resistivity of multiple powder sections to be tested, improving testing efficiency and verifying uniform powder compression. Furthermore, during the test, the powder's own heat generation eliminates the effects of moisture, further improving test accuracy.

[0063] Without limitation to this, any changes or substitutions that are not conceived through creative work should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A multi-channel resistivity testing device, characterized in that: The multi-channel resistivity testing device comprises a power supply (1) and a current detection module (2); one pole of the power supply (1) is provided with a first main probe (7); the other pole of the power supply (1) is provided with a second main probe (8); the first main probe (7) is applied to the upper end surface (61) of the resistor column (6) and forms an electrical connection with the resistor column (6); the second main probe (8) is applied to the lower end surface (62) of the resistor column (6) and forms an electrical connection with the resistor column (6); The side wall of the resistor column (6) is provided with a voltage detection probe T i , the voltage detection probe T i Through the voltage detection switch K i Forming an electrical connection with a voltage detection module (3), wherein, i=1, 2, 3, ..., n.

2. The multi-channel resistivity testing device according to claim 1, characterized in that: The voltage detection probe T i A temperature sensor S is provided on one side of i , the temperature sensor S i Probe the voltage detection probe T i The temperature of the temperature sensor S i Forming an electrical connection with a temperature detection module (4), wherein i=1, 2, 3, ..., n.

3. The multi-channel resistivity testing device according to claim 2, characterized in that: A first switch (31) is provided between the voltage detection module (3) and the upper end surface (61) of the resistor column (6), and a second switch (32) is provided between the voltage detection module (3) and the lower end surface of the resistor column (6).

4. The multi-channel resistivity testing device according to claim 1, characterized in that: The resistor column (6) is a columnar compressed body obtained by compressing solid powder.

5. The multi-channel resistivity testing device according to claim 1, characterized in that: The resistor column (6) is a mixture of solid powder and liquid.

6. The multi-channel resistivity testing device according to claim 1, characterized in that: The power supply (1) is an adjustable power supply.

7. The multi-channel resistivity testing device according to claim 1, characterized in that: The voltage detection probe T i Needle-shaped, where i=1,2,…,n.

8. The multi-channel resistivity testing device according to claim 1, characterized in that: The voltage detection probe T i It is in the shape of a ring, where i=1,2,…,n.

9. A method for measuring resistivity using the multi-channel resistivity testing device as claimed in claim 3, comprising the steps of: Step S1, placing a resistance column (6) to be tested on an insulating fixture (9), and applying pressure to the resistance column (6); Step S2, turning on the power supply (1), applying a preliminary detection current I0 to the first main probe (7) and the second main probe (8), closing the first switch (31) and the second switch (32), and the voltage detection module (3) detecting a preliminary detection voltage U0 between the first main probe (7) and the second main probe (8), and obtaining a preliminary detection resistance value R0=U0 / I0 of the resistance column (6); Step S3, adjusting the voltage of the power supply (1) according to the size of the preliminary detected resistance value R0 of the resistor column (6), heating the resistor column (6), until the temperature detection module (4) detects that the temperature sensor S i All reach the preset temperature T e ,in, i=1,2,…,n; Step S4: close the voltage detection switch K i any two of them, the voltage detection module (3) detects a voltage U between the two voltage detection probes, and the current detection module (2) detects a current I, wherein i=1, 2, ..., n; Step S5, calculating the resistance R=U / I between the two voltage detection probes; Step S6, calculating the resistivity ρ0=R*S / l, where S is the cross-sectional area of ​​the resistor column (6), and l is the distance between the two voltage detection probes.

10. The multi-channel resistivity testing device according to claim 9, characterized in that: The resistor column (6) is a columnar compressed body obtained by compressing solid powder, or a mixture of solid powder and liquid.

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