A six-point roll-to-roll transmission high-temperature superconducting long tape critical current test device and method

Abstract

The present invention discloses a six-point method roll-to-roll drive type high-temperature superconducting long tape critical current testing device and method, including a testing chamber, a chamber cover and a pay-off chamber. The chamber cover is provided above the testing chamber, and a pay-off chamber is provided at the middle position of the top of the chamber cover. Driving chambers are provided on both sides of the top of the chamber cover. U-shaped frames are provided on both sides of the bottom inside the testing chamber, and baffles are provided on the tops of the U-shaped frames. Pneumatic cylinders are provided inside the two driving chambers, and the output ends of the two pneumatic cylinders respectively extend into the two U-shaped frames. The present invention uses a six-point type test. In the main measurement section, according to the measurement standard of the superconducting tape sample, when the voltage measurement value reaches a cut-off voltage value greater than V C , the current source stops conducting current, and the measurement of this section is completed. In the two sub-measurement sections, the upper limit value of the voltage set artificially is higher than the set multiple of the cut-off voltage value of the above-mentioned main measurement section relative to V C to prevent damage to the sub-measurement sections.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting tapes, and in particular to a six-point roll-to-roll transmission type high-temperature superconducting long tape critical current testing device and method. Background Art

[0002] Practical high-temperature superconducting materials mainly include the first-generation Bi-based PIT tapes and the second-generation Y-based coated conductor tapes; because the current carrying capacity of these two types of superconducting tapes, i.e., the critical current, is quite sensitive to the microstructural defects in the internal materials;

[0003] The measurement standard for the critical current of high-temperature superconducting materials generally adopts the four-lead method, that is, the current lead and the voltage lead are connected at both ends of the material, with the current lead outside and the voltage lead inside. When measuring, the current I a Flow direction I b , monitor voltage drop V = V a –V b , and determine its critical current I based on the IV curve data obtained c The above method has the following problems: a To V a and V b to I b During measurement, it cannot be monitored or protected. When the critical current is lower than the main measurement section "V a -V b " may be damaged; in the measurement of superconducting long tapes, the current lead needs to inject a current of up to hundreds of amperes into the superconducting tape through a crimping method. There is contact resistance on the crimped surface, which causes heat to be generated at the interface between the current contact and the surface of the superconducting tape, which may cause damage in severe cases. Therefore, the present invention proposes a six-point method roll-to-roll transmission high-temperature superconducting long tape critical current testing device and method to solve the problems existing in the prior art. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to propose a six-point method roll-to-roll transmission high-temperature superconducting long tape critical current testing device and method, which can prevent damage to the auxiliary measurement section and avoid damage caused by heating at the contact point.

[0005] To achieve the purpose of the present invention, the present invention is implemented by the following technical scheme: a six-point method roll-to-roll transmission type high-temperature superconducting long tape critical current test device, comprising a test chamber, a chamber cover and an unwinding chamber, a chamber cover is provided above the test chamber, and an unwinding chamber is provided at the middle position of the top of the chamber cover, driving chambers are provided on both sides of the top of the chamber cover, U-shaped frames are provided on both sides of the bottom of the test chamber, and a baffle is provided on the top of the U-shaped frame, pneumatic cylinders are provided inside two groups of the driving chambers, and the output ends of the two groups of the pneumatic cylinders extend into the two groups of the U-shaped frames respectively, and push rods are provided at the output ends of the two groups of the pneumatic cylinders, a first pressure block is provided below the push rod on the left, and a second pressure block is provided below the push rod on the right, a first voltage contact, a second voltage contact, a third voltage contact and a first current contact are provided at the bottom of the first pressure block, and the first current contact and the second voltage contact are integrated contact points, a fourth voltage contact, a fifth voltage contact, a sixth voltage contact and a second current contact are provided at the bottom of the second pressure block, and the second current contact and the fifth voltage contact are integrated contact points.

[0006] A further improvement is that: the bottom of the inner side of the two groups of U-shaped frames are provided with support blocks, and the support blocks on both sides are respectively matched with the first pressure block and the second pressure block, and the outer side of the bottom of the two groups of baffles are provided with support shafts, and a limiting wheel is provided under the support shafts.

[0007] Further improvements are: the interior of the test chamber is filled with liquid refrigerant, and the first and second reel-up and reel-up are rotatably installed on both sides of the unwinding chamber, and a superconducting tape is wound on the first rewinding and reel-up. One side of the two groups of driving chambers are rotatably installed with guide wheels, and one end of the superconducting tape passes around the guide wheel on the left, the limiting wheel on the left, under the first pressure block, under the second pressure block, the limiting wheel on the right, the guide wheel on the right, and onto the second reel-up, and the superconducting tape is immersed in the liquid refrigerant.

[0008] A further improvement is that: the first voltage contact, the second voltage contact, the third voltage contact, the fourth voltage contact, the fifth voltage contact, and the sixth voltage contact are all connected to voltage leads, and the first current contact and the second current contact are all connected to current leads.

[0009] A further improvement is that: both ends of the two sides of the test chamber are provided with electric push rods, both ends of the two sides of the chamber cover are provided with supporting feet, and the output ends of the electric push rods are connected to the supporting feet.

[0010] A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing method comprises the following steps:

[0011] Step 1: Through the action of the first reel and the second reel, the superconducting tape is introduced into the measurement area of ​​the liquid refrigerant in a roll-to-roll manner, and the first voltage contact is set to V a0 , the second voltage contact is V a1 , the third voltage contact is V a2 , the fourth voltage contact is V b0 , the fifth voltage contact is V b1 , the sixth voltage contact is V b2 , the first current contact is I a , the second current contact is I b ;

[0012] Step 2: During the tape running process, the first pressing block and the second pressing block have no mechanical contact with the superconducting tape. During the measurement, the superconducting tape stops running and the measured section is stationary. The first pressing block and the second pressing block cooperate with the support block to clamp the measured section by the action of the pneumatic cylinder. a and I b The current contact forms a close contact interface with the surface of the superconducting tape under mechanical pressure to obtain a contact resistance of micro-ohm level, V a1 and V b1 Respectively with I a ,I b Share a contact point, obtain the voltage value measurement, and connect the lead wire to the position near the contact interface between the electrode and the superconducting tape. At this time, the current flows from the current contact point from I a ,I b Injection and outflow, as the current increases at the set rate, respectively with the voltage contact group "V a0 and V b0 ”, “V a2 and V a0 ”, “V a1 and V a0 ”, “V b2 and V b0 ”, “V b1 and V b0 ” The connected voltmeter obtains the measurement result;

[0013] Step 3: In the main measurement section, i.e. "V a0 ” to “V b0 ", set I C Its superconducting critical current, V C The corresponding voltage criterion is set to 1μV / cm according to the measurement standard of the superconducting tape sample. When the voltage measurement value reaches greater than V C When a cut-off voltage value is reached, the current source stops flowing, the measurement of this section is completed, and the IV curve is obtained;

[0014] Step 4: In the two secondary measurement sections, namely "Va2 To V a0 ” and “V b2 To V b0 ”, set V th The voltage upper limit is set manually. This voltage upper limit is higher than the cut-off voltage of the main measurement section in step 3 above. C The setting multiple of the I c Under uniform conditions, V th The setting value ensures that the above main measuring section obtains a complete IV curve. When the inhomogeneity of the superconducting tape is obvious, the position of the measured section is adjusted to obtain more valuable data;

[0015] Step 5: Build I a and I b The IV curves of the two current contacts are used to reflect the contact resistance and its changes. Under normal circumstances, the IV curve is a straight line with a slope in the micro-ohm range, and the slope remains unchanged during the entire current rise process. The tests of step three and step four are carried out normally. Under abnormal circumstances, one has a large initial slope of 20μΩ-100μΩ; the other has a small initial slope. When the current rises to the value, the slope of the IV curve of the current contact increases, indicating that the Joule heat generated by the contact resistance at the current contact cannot be completely dissipated in the liquid refrigerant, resulting in an increase in the temperature of the contact interface of the current contact. At this time, the test is terminated, the position of the measured segment is replaced, and the electrode is checked;

[0016] Step 6: After each measured section is measured, the clamping state of the measured section ends, the superconducting tape returns to the roll-to-roll transmission mode, another section of the superconducting tape is introduced into the measurement area, and the above test process is repeated.

[0017] A further improvement is that in step 4, the voltage upper limit value is higher than the cut-off voltage value of the main measurement section in step 3 relative to V C The setting multiple is 10-20 times to prevent the secondary measuring section from being damaged.

[0018] The beneficial effects of the present invention are as follows: the present invention performs measurement through a first voltage contact, a second voltage contact, a third voltage contact, a first current contact, a fourth voltage contact, a fifth voltage contact, a sixth voltage contact, and a second current contact, wherein the first current contact and the second voltage contact are integrated contact points, and the second current contact and the fifth voltage contact are integrated contact points, and the overall six-point test is performed. In the main measurement section, according to the measurement standard of the superconducting tape sample, when the voltage measurement value reaches greater than V C When the cut-off voltage value is reached, the current source stops flowing and the measurement of this section is completed. In the two auxiliary measurement sections, the artificially set voltage upper limit value is higher than the cut-off voltage value of the main measurement section relative to V CThe setting multiple is within 10 times to prevent the secondary measuring section from being damaged, and the present invention constructs I a and I b The IV curves of the two current contacts reflect the contact resistance and its changes. Under abnormal circumstances, when the current rises to a certain value, the slope of the IV curve of the current contact increases, indicating that the Joule heat generated by the contact resistance at the current contact cannot be completely dissipated in the liquid refrigerant, resulting in an increase in the temperature of the contact interface of the current contact. At this time, the test is terminated, the position of the measured segment is replaced, and the electrode is checked to avoid damage caused by heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of the present invention;

[0020] Figure 2 It is a schematic diagram of the internal structure of the present invention;

[0021] Figure 3 It is a schematic diagram of the U-shaped frame on the left side of the present invention;

[0022] Figure 4 It is a schematic diagram of the U-shaped frame on the right side of the present invention;

[0023] Figure 5 It is a schematic diagram of a first pressing block of the present invention;

[0024] Figure 6 is a schematic diagram of a second pressing block of the present invention;

[0025] Figure 7 is an equivalent schematic diagram of the contact point of the present invention;

[0026] Figure 8 It is a schematic diagram of the IV curve of the main measurement section of the present invention;

[0027] Fig. 9 V of the present invention a2 To V a0 Schematic diagram of segment IV curve;

[0028] Fig.10 V of the present invention b2 To V b0 Schematic diagram of segment IV curve;

[0029] Fig.11 The IV curve diagram of the main measurement section when the superconducting tape of the present invention is uniform;

[0030] Fig.12 The IV curve diagram of the main measurement section when the superconducting tape of the present invention is uneven;

[0031] Fig.13The IV curve diagram of two current contacts under normal conditions of the present invention;

[0032] Fig.14 The IV curve diagram of two current contacts under abnormal conditions of the present invention;

[0033] Fig.15 This is a graph of measured data obtained on the silver-coated second-generation high-temperature superconducting tape of the present invention.

[0034] Among them: 1. test chamber; 2. chamber cover; 3. unwinding chamber; 4. driving chamber; 5. U-shaped frame; 6. baffle; 7. pneumatic cylinder; 8. push rod; 9. first pressure block; 10. second pressure block; 11. first voltage contact; 12. second voltage contact; 13. third voltage contact; 14. first current contact; 15. fourth voltage contact; 16. fifth voltage contact; 17. sixth voltage contact; 18. second current contact; 19. support block; 20. support shaft; 21. limit wheel; 22. liquid refrigerant; 23. first unwinding and reel; 24. second unwinding and reel; 25. superconducting tape; 26. guide wheel; 27. electric push rod; 28. support foot. DETAILED DESCRIPTION

[0035] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0036] according to Figure 1 , 2 As shown in Figures 3, 4, 5 and 6, this embodiment provides a six-point roll-to-roll transmission type high-temperature superconducting long tape critical current testing device, comprising a testing chamber 1, a chamber cover 2 and an unwinding chamber 3, wherein the chamber cover 2 is provided above the testing chamber 1, and the unwinding chamber 3 is provided at the middle position of the top of the chamber cover 2, driving chambers 4 are provided on both sides of the top of the chamber cover 2, U-shaped frames 5 are provided on both sides of the bottom of the testing chamber 1, and a baffle 6 is provided on the top of the U-shaped frame 5, two groups of the driving chambers 4 are provided with pneumatic cylinders 7, and the output ends of the two groups of the pneumatic cylinders 7 extend to the two groups of the U-shaped frames 5 respectively, and the two groups of the pneumatic cylinders 7 are provided with a plurality of pneumatic cylinders 7. The output end of the cylinder 7 is provided with a push rod 8, a first pressure block 9 is provided under the push rod 8 on the left, and a second pressure block 10 is provided under the push rod 8 on the right, a first voltage contact 11, a second voltage contact 12, a third voltage contact 13 and a first current contact 14 are provided at the bottom of the first pressure block 9, and the first current contact 14 and the second voltage contact 12 are integrated contact points, a fourth voltage contact 15, a fifth voltage contact 16, a sixth voltage contact 17 and a second current contact 18 are provided at the bottom of the second pressure block 10, and the second current contact 18 and the fifth voltage contact 16 are integrated contact points.

[0037] The bottom of the inner side of the two groups of U-shaped frames 5 is provided with a support block 19, and the support blocks 19 on both sides are respectively matched with the first pressing block 9 and the second pressing block 10. The outer side of the bottom of the two groups of baffles 6 is provided with a support shaft 20, and a limiting wheel 21 is provided under the support shaft 20.

[0038] The interior of the test chamber 1 is filled with liquid refrigerant 22, and the first and second rewinding and unwinding reels 23 and 24 are rotatably installed on both sides of the unwinding chamber 3, and a superconducting tape 25 is wound on the first rewinding and unwinding reel 23. A guide wheel 26 is rotatably installed on one side of the two groups of driving chambers 4. One end of the superconducting tape 25 passes around the guide wheel 26 on the left, the limiting wheel 21 on the left, under the first pressure block 9, under the second pressure block 10, the limiting wheel 21 on the right, the guide wheel 26 on the right, and onto the second rewinding and unwinding reel 24, and the superconducting tape 25 is immersed in the liquid refrigerant 22.

[0039] The first voltage contact 11 , the second voltage contact 12 , the third voltage contact 13 , the fourth voltage contact 15 , the fifth voltage contact 16 , and the sixth voltage contact 17 are all connected to voltage leads, and the first current contact 14 and the second current contact 18 are all connected to current leads.

[0040] Both ends of the two sides of the test chamber 1 are provided with electric push rods 27 , and both ends of the two sides of the chamber cover 2 are provided with supporting feet 28 , and the output ends of the electric push rods 27 are connected to the supporting feet 28 .

[0041] according to Figure 7 , 8 As shown in , 9, 10, 11, 12, 13, 14, and 15, this embodiment provides a six-point method roll-to-roll transmission high-temperature superconducting long tape critical current test method, including the following steps:

[0042] Step 1: Through the action of the first reel 23 and the second reel 24, the superconducting tape 25 is introduced into the measuring area of ​​the liquid refrigerant 22 in a roll-to-roll manner, and the first voltage contact 11 is set to V a0 , the second voltage contact 12 is V a1 , the third voltage contact 13 is V a2 , the fourth voltage contact 15 is V b0 , the fifth voltage contact 16 is V b1 , the sixth voltage contact 17 is V b2 , the first current contact 14 is I a , the second current contact 18 is I b ;

[0043] Step 2: During the tape running process, the first pressing block 9 and the second pressing block 10 have no mechanical contact with the superconducting tape. During the measurement, the superconducting tape 25 stops running and the measured section is stationary. The first pressing block 9 and the second pressing block 10 cooperate with the support block 19 to clamp the measured section by the action of the pneumatic cylinder 7. a and I b The current contact forms a close contact interface with the surface of the superconducting tape 25 under mechanical pressure to obtain a contact resistance of micro-ohm level, V a1 and V b1 Respectively with I a ,I b A common contact point is used to obtain the voltage value, and a lead is connected to the position of the contact interface between the electrode and the superconducting tape 25. At this time, the current flows from the current contact point from I a ,I b Injection and outflow, as the current increases at the set rate, respectively with the voltage contact group "V a0 and V b0 ”, “V a2 and V a0 ”, “V a1 and V a0 ”, “V b2 and V b0 ”, “V b1 and V b0 ” The connected voltmeter obtains the measurement result;

[0044] Step 3: In the main measurement section, that is, "V a0 ” to “V b0 ", set I C Its superconducting critical current, V C The corresponding voltage criterion is set to 1μV / cm according to the measurement standard of the superconducting tape 25 sample. When the voltage measurement value reaches greater than V C When a cut-off voltage value is c 1.1, 2, 5, 10 times of the current source, etc., the current source stops flowing, the measurement of this section is completed, and the IV curve is obtained, such as Figure 8 ;

[0045] Step 4: In the two secondary measurement sections, namely "V a2 To V a0 ” and “V b2 To V b0 ", such as Fig. 9 , Fig.10 , set V th The voltage upper limit is set manually. This voltage upper limit is higher than the cut-off voltage of the main measurement section in step 3 above. C The setting multiple is 10-20 times to prevent the secondary measurement section from being damaged.c Under uniform conditions, V th The setting value ensures that the above main measuring section obtains a complete IV curve. When the superconducting tape 25 has obvious inhomogeneity, the position of the measured section is adjusted to obtain more valuable data; Fig.11 , V c The measurement cutoff voltage is set to 240 μV (1.2 V c ), and the length of the two auxiliary measurement sections is 2.5 cm, and its V th Set to 30μV (12V c ), the IV curve of the main measurement section rises above I c , the voltage exceeds V c After obtaining complete measurement data, the voltage measured on the two auxiliary measurement segments has shown an exponential upward trend, but is still less than 20μV; the IV curve of the main measurement segment is measured, and the I c =213A, N=35, but when the inhomogeneity of the superconducting tape is more obvious, the results will be different. Fig.12 Another set of actual measurement data is shown, V c The cut-off voltage is set to 240 μV (1.2 V c ), and the length of the two auxiliary measurement sections is also 2.5cm, and its V th Set to 30μV (12V c ), when the current rises to above 210A, in the secondary measurement section, that is, "V a2 To V a0 The voltage measured at the "V b2 To V b0 The voltage measured at ” is still zero, and the voltage of the main measurement section has shown an exponential upward trend, but has not yet reached V c value, i.e. 200μV. In this case, in order to avoid the secondary measurement section “V a2 To V a0 "Local overheating or even burning, the measurement must be interrupted, so the IV curve data of the main measurement section is incomplete. c The estimated value is 210A, and the N value cannot be obtained. In more serious cases, when the current rises to a certain value I', the voltage measured in the main measurement section may not show an exponential upward trend, but the voltage of one or two auxiliary measurement sections has exceeded V thIn order to prevent the superconducting tape 25 from being damaged during measurement, the measurement must be stopped, and the accurate values ​​of the main measurement section are obtained; if the current is continued to increase, it may cause the superconducting tape 25 to be damaged and the measurement data cannot be obtained. In this case, the position of the measured section is adjusted to obtain more valuable data;

[0046] Step 5: Build I a and I b The IV curves of two current contacts reflect the contact resistance and its changes. Under normal circumstances, such as Fig.13 The IV curve is a straight line with a slope in the micro-ohm range and remains constant during the entire current rise process. The tests in steps 3 and 4 are carried out normally. In abnormal situations, such as Fig.14 One is that the initial slope is large, 20μΩ-100μΩ, and an appropriate value is selected according to the structure and surface condition of the measured HTS superconducting tape; the other is that the initial slope is small. When the current rises to the value, the slope of the IV curve of the current contact increases, indicating that the Joule heat generated by the contact resistance at the current contact cannot be completely dissipated in the liquid refrigerant 22, resulting in an increase in the temperature of the contact interface of the current contact. At this time, the test is terminated, the position of the measured section is replaced, and the electrode is checked; the measured data obtained on the silver-coated second-generation high-temperature superconducting tape are as follows Fig.15 As shown, the current contact IV data - normal situation: the slope is 2.1μΩ, which remains basically unchanged during the entire current rise process; abnormal situation: the initial slope value is 1.66μΩ, and when the current rises to 180A, the slope changes and suddenly rises to more than about 20μΩ, causing the test to be terminated;

[0047] Step 6: After each measured section is measured, the clamping state of the measured section ends, the superconducting tape 25 returns to the roll-to-roll transmission mode, another section of the superconducting tape 25 is introduced into the measurement area, and the above test process is repeated.

[0048] The present invention performs measurement through the first voltage contact 11, the second voltage contact 12, the third voltage contact 13, the first current contact 14, the fourth voltage contact 15, the fifth voltage contact 16, the sixth voltage contact 17, and the second current contact 18, wherein the first current contact 14 and the second voltage contact 12 are integrated contact points, the second current contact 18 and the fifth voltage contact 16 are integrated contact points, and the overall six-point test is performed. In the main measurement section, according to the measurement standard of the superconducting tape 25 sample, when the voltage measurement value reaches greater than V C When the cut-off voltage value is reached, the current source stops flowing and the measurement of this section is completed. In the two auxiliary measurement sections, the artificially set voltage upper limit value is higher than the cut-off voltage value of the main measurement section relative to V CThe setting multiple is within 10 times to prevent the secondary measuring section from being damaged, and the present invention constructs I a and I b The IV curves of the two current contacts reflect the contact resistance and its changes. Under abnormal circumstances, when the current rises to a certain value, the slope of the IV curve of the current contact increases, indicating that the Joule heat generated by the contact resistance at the current contact cannot be completely dissipated in the liquid refrigerant, resulting in an increase in the temperature of the contact interface of the current contact. At this time, the test is terminated, the position of the measured segment is replaced, and the electrode is checked to avoid damage caused by heat.

[0049] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A six-point roll-to-roll transmission type high-temperature superconducting long tape critical current testing device, comprising a testing chamber (1), a chamber cover (2) and an unwinding chamber (3), Features: A bin cover (2) is provided above the test bin (1), and a reeling bin (3) is provided at the middle position of the top of the bin cover (2). Drive bins (4) are provided on both sides of the top of the bin cover (2). U-shaped frames (5) are provided on both sides of the bottom of the test bin (1), and a baffle (6) is provided on the top of the U-shaped frame (5). Pneumatic cylinders (7) are provided inside the two groups of the drive bins (4), and the output ends of the two groups of the pneumatic cylinders (7) extend into the two groups of the U-shaped frames (5) respectively. Push rods (8) are provided at the output ends of the two groups of the pneumatic cylinders (7), and a first pressing block (6) is provided below the left push rod (8). 9), a second pressing block (10) is provided below the push rod (8) on the right side, a first voltage contact (11), a second voltage contact (12), a third voltage contact (13) and a first current contact (14) are provided at the bottom of the first pressing block (9), the first current contact (14) and the second voltage contact (12) are integrated contact points, a fourth voltage contact (15), a fifth voltage contact (16), a sixth voltage contact (17) and a second current contact (18) are provided at the bottom of the second pressing block (10), the second current contact (18) and the fifth voltage contact (16) are integrated contact points; The first voltage contact (11) is Va0, the second voltage contact (12) is Va1, the third voltage contact (13) is Va2, the fourth voltage contact (15) is Vb0, the fifth voltage contact (16) is Vb1, the sixth voltage contact (17) is Vb2, the first current contact (14) is Ia, and the second current contact (18) is Ib; The main measurement section is from "Va0" to "Vb0", and the two secondary measurement sections are from "Va2" to "Va0" and from "Vb2" to "Vb0".

2. A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing device according to claim 1, Features: The bottom of the inner side of the two sets of U-shaped frames (5) is provided with a support block (19), and the support blocks (19) on both sides are respectively matched with the first pressing block (9) and the second pressing block (10), and the outer side of the bottom of the two sets of baffles (6) is provided with a support shaft (20), and a limiting wheel (21) is provided under the support shaft (20).

3. A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing device according to claim 2, Features: The interior of the test chamber (1) is filled with liquid refrigerant (22), and the first rewinding reel (23) and the second rewinding reel (24) are rotatably mounted on both sides of the interior of the unwinding chamber (3), and a superconducting tape (25) is wound around the first rewinding reel (23). A guide wheel (26) is rotatably mounted on one side of the interior of the two sets of driving chambers (4), and one end of the superconducting tape (25) passes around the guide wheel (26) on the left, the limit wheel (21) on the left, the bottom of the first pressure block (9), the bottom of the second pressure block (10), the limit wheel (21) on the right, the guide wheel (26) on the right, and reaches the second rewinding reel (24), and the superconducting tape (25) is immersed in the liquid refrigerant (22).

4. A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing device according to claim 1, Features: The first voltage contact (11), the second voltage contact (12), the third voltage contact (13), the fourth voltage contact (15), the fifth voltage contact (16), and the sixth voltage contact (17) are all connected to voltage leads, and the first current contact (14) and the second current contact (18) are all connected to current leads.

5. A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing device according to claim 1, Features: Both ends of the two sides of the test chamber (1) are provided with electric push rods (27), and both ends of the two sides of the chamber cover (2) are provided with supporting feet (28), and the output ends of the electric push rods (27) are connected to the supporting feet (28).

6. A testing method for a six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing device based on claim 1 above, It is characterized in that The following steps are involved: Step 1: by means of the first reel (23) and the second reel (24), the superconducting tape (25) is introduced into the measuring area of ​​the liquid refrigerant (22) in a roll-to-roll manner, section by section, and the first voltage contact (11) is set to Va0, the second voltage contact (12) is set to Va1, the third voltage contact (13) is set to Va2, the fourth voltage contact (15) is set to Vb0, the fifth voltage contact (16) is set to Vb1, the sixth voltage contact (17) is set to Vb2, the first current contact (14) is set to Ia, and the second current contact (18) is set to Ib; Step 2: During the tape running process, the first pressing block (9) and the second pressing block (10) have no mechanical contact with the superconducting tape. During measurement, the superconducting tape (25) stops running, the measured section is stationary, and the first pressing block (9) and the second pressing block (10) cooperate with the support block (19) to clamp the measured section by using the action of the pneumatic cylinder (7). a and I b The current contact forms a close contact interface with the surface of the superconducting tape (25) under mechanical pressure to obtain a contact resistance of micro-ohm level, V a1 and V b1 Respectively with I a ,I b A voltage value is measured by sharing a contact point, and a lead is connected to a position near the contact interface between the electrode and the superconducting tape (25). At this time, the current flows from the current contact point from I a ,I b Injection and outflow, as the current increases at the set rate, respectively with the voltage contact group "V a0 and V b0 ”、"V a2 and V a0 ”、"V a1 and V a0 ”、"V b2 and V b0 ”、"V b1 and V b0 ” The connected voltmeter obtains the measurement result; Step 3: In the main measurement section, i.e., from "Va0" to "Vb0", IC is set as its superconducting critical current, VC is set as the corresponding voltage criterion, and is set to 1 μV / cm according to the measurement standard of the superconducting tape (25) sample. When the voltage measurement value reaches a cut-off voltage value greater than VC, the current source stops flowing, the measurement of this section is completed, and the IV curve is obtained; Step 4: In the two secondary measurement sections, namely "Va2 to Va0" and "Vb2 to Vb0", set Vth to an artificially set voltage upper limit value, which is higher than the cut-off voltage value of the main measurement section in step 3 above relative to V C The setting multiples of I in the superconducting tape (25) c Under uniform conditions, V th The setting value ensures that the above main measuring section obtains a complete IV curve. When the superconducting tape (25) has obvious inhomogeneity, the position of the measured section is adjusted to obtain more valuable data; Step 5: Build I a and I b The IV curves of the two current contacts are used to reflect the contact resistance and its changes. Under normal circumstances, the IV curve is a straight line with a slope in the micro-ohm range and remains unchanged during the entire current rise process. The tests of step three and step four are carried out normally. Under abnormal circumstances, one has a large initial slope of 20 mW-100 mW; the other has a small initial slope. When the current rises to the value, the slope of the IV curve of the current contact increases, indicating that the Joule heat generated by the contact resistance at the current contact cannot be completely dissipated in the liquid refrigerant (22), resulting in an increase in the temperature of the contact interface of the current contact. At this time, the test is terminated, the position of the measured section is replaced, and the electrode is checked; Step 6: After each measured section is measured, the clamping state of the measured section ends, the superconducting tape (25) returns to the roll-to-roll transmission mode, another section of the superconducting tape (25) is introduced into the measurement area, and the above test process is repeated.

7. A six-point roll-to-roll transmission high-temperature superconducting long tape critical current testing method according to claim 6, Features: In step 4, the voltage upper limit value is higher than the cut-off voltage value of the main measurement section in step 3 relative to V C The setting multiple is 10-20 times to prevent the secondary measuring section from being damaged.

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