Second-generation high-temperature superconducting strip composite structure and preparation method thereof

Abstract

The invention provides a second-generation high-temperature superconducting tape composite structure and a preparation method thereof, the second-generation high-temperature superconducting tape composite structure comprises two second-generation high-temperature superconducting tapes and indium foil, and the outer surfaces of the two second-generation high-temperature superconducting tapes are coated with silver layers; the indium foil is arranged between the two second-generation high-temperature superconducting tapes, and the two second-generation high-temperature superconducting tapes are in composite connection with the indium foil to form a silver-indium alloy layer serving as a middle layer and the two second-generation high-temperature superconducting tapes located on the two sides of the middle layer respectively. A current shunting structure is formed by setting the thickness ratio of the silver-indium alloy layer, the silver layer on one side of the superconducting layer and the silver layer on one side of the metal base band and the silver layer fully coated on the side surface, and when the band is quenched, the current flows through the silver layer on the side surface and increases heat production along a long current propagation path, so that the quenching propagation speed is improved, the superconducting band is protected, and the service life of the superconducting band is prolonged. The quench propagation speed of the second-generation high-temperature superconducting strip prepared by the preparation method is not lower than 130 cm / s under the condition of 70 A, and is increased by 5-8 times compared with other second-generation high-temperature superconducting strips.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting materials, and in particular to a second-generation high-temperature superconducting tape composite structure and a preparation method thereof. Background Art

[0002] The second-generation high-temperature superconducting tapes have the advantages of high transition temperature, high irreversible field, and high current carrying capacity, and are widely used in electricity, magnets, metallurgy and other fields.

[0003] The critical current of the second-generation high-temperature superconducting tape is unevenly distributed along the length direction, with fluctuations of 10 to 20%. During the complex service process of the second-generation high-temperature superconducting tape, changes in stress and temperature will have a significant impact on its critical current, and it is possible that the operating current will approach or exceed the critical current of the tape. At this time, the second-generation high-temperature superconducting tape will experience local quenching. If the superconducting tape quench is not detected in time and a response is not made, the temperature of the quenching area will rise sharply, causing irreversible damage to the superconducting tape. This area that quenches first is called a hot spot. The quench propagation speed of the superconducting tape determines the time when the tape quench is detected. Increasing the quench propagation speed can shorten the time from the tape quenching to the reduction of the operating current, thereby protecting the superconducting tape.

[0004] In addition, in existing superconducting tape products, the superconducting layer is usually not located in the geometric neutral layer of the tape. Since the intrinsic property of superconducting materials is sensitive to stretching, there are differences in the critical bending performance of superconducting tapes to the inside and outside of the superconducting layer. The bending diameter of the outside of the existing second-generation high-temperature superconducting tape is about 7mm, and the bending diameter of the inside is about 3mm, which limits the practical engineering application of superconducting tapes. Regulating the position of the neutral layer of the superconducting tape so that the superconducting layer is near the neutral layer can improve the critical bending performance of the superconducting tape. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a second-generation high-temperature superconducting tape composite structure and a preparation method thereof.

[0006] The second-generation high-temperature superconducting tape composite structure provided by the present invention comprises two second-generation high-temperature superconducting tapes to be composited and an indium foil, wherein the outer surfaces of the two second-generation high-temperature superconducting tapes to be composited are both coated with a silver layer;

[0007] The indium foil is arranged between two second-generation high-temperature superconducting tapes to be composited, and the two second-generation high-temperature superconducting tapes to be composited are compositely connected with the indium foil to form a silver-indium alloy layer as an intermediate layer and two composite second-generation high-temperature superconducting tapes located on both sides of the intermediate layer.

[0008] Preferably, the two composite second-generation high-temperature superconducting tapes are symmetrically arranged on both sides of the silver-indium alloy layer.

[0009] Preferably, the second generation high temperature superconducting tape to be composited and the indium foil are connected by ultrasonic welding.

[0010] Preferably, the composite second-generation high-temperature superconducting tape comprises a superconducting layer and a metal base tape which are stacked, and the superconducting layer is arranged on a side of the metal base tape close to the silver-indium alloy layer;

[0011] The composite second-generation high-temperature superconducting tape is coated with silver layers on all sides, and the silver layers on one side of the superconducting layer in the two composite second-generation high-temperature superconducting tapes are connected through a silver-indium alloy layer.

[0012] Preferably, a transition layer is provided between the superconducting layer and the metal base tape.

[0013] Preferably, the thickness ratio between the silver layer between the superconducting layer and the silver-indium alloy layer and the silver layer covering the side of the metal base tape away from the superconducting layer is 0.01-0.2.

[0014] Preferably, the silver layer on the outer surface of the second-generation high-temperature superconducting tape to be composited is deposited using a multi-pass roll-to-roll technology, and the angles between the left outermost track and the right outermost track and the target plane are 15-30° and -15--30° respectively.

[0015] Preferably, the side surfaces of the second-generation high-temperature superconducting tape to be composited are completely covered by the silver layer without any exposed parts, and the thickness of the silver layer on the side surfaces is 10-100 nm.

[0016] The method for preparing the second-generation high-temperature superconducting tape composite structure provided by the present invention is used to prepare the second-generation high-temperature superconducting tape composite structure, comprising the following steps:

[0017] Step S1: selecting indium foil of corresponding specifications according to the specifications of the second-generation high-temperature superconducting tape to be composited;

[0018] Step S2: arranging two second-generation high-temperature superconducting tapes to be composited on the upper and lower sides of the indium foil respectively;

[0019] Step S3: using a roll-to-roll pre-combination process, the two second-generation high-temperature superconducting tapes to be composited and the indium foil are simultaneously passed through a pressure device to form a pre-combined second-generation high-temperature superconducting tape;

[0020] Step S4: adopting a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is welded by an ultrasonic welding device to form a second-generation high-temperature superconducting tape composite structure.

[0021] Preferably, in step S1, the second generation high temperature superconducting tape to be composited has a thickness of 20-150 μm and a width of 2-12 mm;

[0022] In the second generation high temperature superconducting tape to be composited, the thickness of the silver layer on the superconducting layer side and the thickness of the silver layer on the metal base tape side are both 1-2 μm, and the difference in the thickness of the silver layer on the superconducting layer side of the two second generation high temperature superconducting tapes to be composited is -100-100 nm;

[0023] The thickness of the indium foil is 0.5-1.0 μm thicker than the thickness of the silver layer on one side of the superconducting layer of the second-generation high-temperature superconducting tape to be composited, and the width is 0.01-0.1 mm narrower than the second-generation high-temperature superconducting tape to be composited;

[0024] In step S2, the silver layer on the side of the second generation high temperature superconducting tape to be composited close to the superconducting layer is opposite to the indium foil;

[0025] In step S3, a tension of 2-7N is applied to the second-generation high-temperature superconducting tape to be composited, and no tension is applied to the indium foil. The pressure device uses a roller pressure head with a pressure of 2-4 bar. Slits are respectively installed at the front and rear of the pressure device, and the width of the slit is 0.001-0.01mm wider than the second-generation high-temperature superconducting tape to be composited;

[0026] In step S4, the ultrasonic welding device uses a roller pressure head, the amplitude of ultrasonic welding is 30%-50%, the pressure is 3-5 bar, and the tape travel speed of the roll-to-roll device is 10-100 m / h.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention forms a current shunt structure by setting a silver-indium alloy layer, a silver layer on one side of the superconducting layer and a silver layer on one side of the metal base tape in thickness ratio, and a side fully covered silver layer. When the tape quenches, the current will flow through the side silver layer and along the long current propagation path to increase heat generation, thereby increasing the quench propagation speed and protecting the superconducting tape. The second-generation high-temperature superconducting tape prepared by the preparation method of the present invention has a quench propagation speed of not less than 130 cm / s, which is 5 to 8 times higher than that of other second-generation high-temperature superconducting tapes.

[0029] 2. The present invention adjusts the position of the superconducting layer close to the neutral layer of the superconducting tape, reduces the strain of the superconducting layer when the superconducting tape is bent, reduces the critical bending diameter of the superconducting tape, and improves the critical bending performance of the superconducting tape. The two superconducting layers in the composite superconducting tape are symmetrically distributed, so that the superconducting tape has the same bending performance on both sides, which is beneficial to the application of the superconducting tape. The critical bending diameter on both sides does not exceed 1.5 mm, which is more than 50% smaller than that of other second-generation high-temperature superconducting tapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0031] Figure 1 It is a schematic cross-sectional view of the second generation high temperature superconducting tape after compounding in the present invention.

[0032] Figure 2 It is the quench propagation speed of the existing second-generation high-temperature superconducting tapes under different currents.

[0033] Figure 3 This is a relationship diagram between current and quench propagation velocity in Example 1 of a composite structure and preparation method of a second-generation high-temperature superconducting tape of the present invention.

[0034] The figure shows:

[0035] Silver layer 1 Transition layer 4

[0036] Silver-indium alloy layer 2 Metal base tape 5

[0037] Superconducting layer 3 DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0039] The invention discloses a second-generation high-temperature superconducting tape composite structure and a preparation method thereof. The second-generation high-temperature superconducting tape prepared by the method provided by the invention forms a current shunt structure by arranging a silver-indium alloy layer, a thickness ratio of a silver layer on one side of a superconducting layer to a silver layer on one side of a metal base tape, and a side fully covered with a silver layer, so that the quench propagation speed thereof is not less than 130 cm / s, which is 5 to 8 times higher than that of other second-generation high-temperature superconducting tapes. By adjusting the position of the superconducting layer to be close to the neutral layer of the superconducting tape, the critical bending diameter thereof is not more than 1.5 mm, which is more than 50% smaller than that of other second-generation high-temperature superconducting tapes.

[0040] The second-generation high-temperature superconducting tape composite structure provided by the present invention comprises a first second-generation high-temperature superconducting tape to be composited, an indium foil, and a second second-generation high-temperature superconducting tape to be composited, the outer surfaces of the two second-generation high-temperature superconducting tapes to be composited are both coated with a silver layer, the indium foil is arranged between the two second-generation high-temperature superconducting tapes to be composited, and the three are connected by ultrasonic welding, such as Figure 1 As shown, a composite second-generation high-temperature superconducting tape and an Ag2In layer disposed between two composite second-generation high-temperature superconducting tapes are formed;

[0041] The structure of the second-generation high-temperature superconducting tape to be composited is silver, superconducting layer, transition layer, metal base tape, and silver in sequence, wherein the silver layer on the surface of the second-generation high-temperature superconducting tape to be composited is deposited using an improved multi-channel roll-to-roll technology, and the angles between the outermost channel on the left and the outermost channel on the right and the target plane are 15-30° and -15--30° respectively; the side of the second-generation high-temperature superconducting tape to be composited is completely covered by the silver layer without any exposed part, and the thickness of the silver layer on the side is 10-100nm.

[0042] Two composite second-generation high-temperature superconducting tapes are symmetrically arranged on both sides of the silver-indium alloy layer 2. The second-generation high-temperature superconducting tape comprises a superconducting layer 3 and a metal base tape 5 arranged in a stacked manner, and the superconducting layer 3 is arranged on the side of the metal base tape 5 close to the silver-indium alloy layer 2; the composite second-generation high-temperature superconducting tape is coated with a silver layer 1 on all sides, and the silver layer 1 on one side of the superconducting layer 3 in the two composite second-generation high-temperature superconducting tapes is connected through the silver-indium alloy layer 2. A transition layer 4 is arranged between the superconducting layer 3 and the metal base tape 5. The thickness ratio of the silver layer 1 on one side of the superconducting layer 3 of the composite second-generation high-temperature superconducting tape to the silver layer 2 on one side of the metal base tape 5 is 0.01-0.2;

[0043] A method for preparing a second-generation high-temperature superconducting tape composite structure provided by the present invention is used to prepare the above-mentioned second-generation high-temperature superconducting tape composite structure, which specifically comprises the following steps:

[0044] Step S1: selecting indium foil of corresponding specifications according to the specifications of the second-generation high-temperature superconducting tape to be composited;

[0045] Step S2: arranging the first second-generation high-temperature superconducting tape to be composited, the indium foil and the second second-generation high-temperature superconducting tape to be composited in a certain order;

[0046] Step S3: using a roll-to-roll pre-composite process, the first second-generation high-temperature superconducting tape to be composited, the indium foil and the second second-generation high-temperature superconducting tape to be composited are simultaneously passed through a pressure device to form a second-generation high-temperature superconducting tape pre-composite structure;

[0047] Step S4: adopting a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is welded by an ultrasonic welding device to form a second-generation high-temperature superconducting tape composite structure.

[0048] In the step S1, the thickness of the second-generation high-temperature superconducting tape to be composited is 20-150 μm, the width is 2-12 mm, the thickness of the silver layer on one side of the superconducting layer and the thickness of the silver layer on one side of the base tape are both 1-2 μm, and the difference in the thickness of the silver layer on one side of the superconducting layer between the first second-generation high-temperature superconducting tape to be composited and the second second-generation high-temperature superconducting tape to be composited is -100-100 nm; the thickness of the indium foil is 0.5-1.0 μm thicker than the thickness of the silver layer on one side of the superconducting layer of the second-generation high-temperature superconducting tape to be composited, and the width is 0.01-0.1 mm narrower than the second-generation high-temperature superconducting tape to be composited.

[0049] In the step S2, the silver layer close to the superconducting layer of the second generation high temperature superconducting tape to be composited is opposite to the indium foil.

[0050] In step S3, a tension of 2-7N is applied to the second-generation high-temperature superconducting tape to be composited, and no tension is applied to the indium foil. The pressure device uses a roller pressure head with a pressure of 2-4 bar. Slits are respectively installed at the front and rear of the pressure device, and the width of the slit is 0.001-0.01mm wider than the second-generation high-temperature superconducting tape to be composited.

[0051] In step S4, the ultrasonic welding device uses a roller pressure head, the amplitude of ultrasonic welding is 30%-50%, and the pressure is 3-5 bar; the tape running speed of the roll-to-roll device is 10-100 m / h.

[0052] Example 1

[0053] This embodiment provides a composite structure and a preparation method of a second-generation high-temperature superconducting tape, comprising the following steps:

[0054] Step S1: The silver layer of the second-generation high-temperature superconducting tape to be composited has a thickness of 1.5 μm and a width of 4.2 mm, and the indium foil has a thickness of 2.2 μm and a width of 4.15 mm.

[0055] Step S2: Arrange two second generation high temperature superconducting tapes to be composited on the upper and lower sides of the indium foil respectively, with the silver layer 1 on the side of the second generation high temperature superconducting tape to be composited close to the superconducting layer 3 facing the indium foil.

[0056] Step S3: Using a roll-to-roll pre-composite process, a 5N tension is applied to the second generation high temperature superconducting tape to be composited, and no tension is applied to the indium foil. The first second generation high temperature superconducting tape to be composited, the indium foil and the second second generation high temperature superconducting tape to be composited are simultaneously passed through a pressure device to form a second generation high temperature superconducting tape pre-composite structure. The pressure device uses a roller pressure head with a pressure of 3 bar. The pressure device is respectively provided with slits at the front and rear, and the slit width is 4.005 mm.

[0057] Step S4: Using a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is passed through an ultrasonic welding device at a tape speed of 60 m / h to form a second-generation high-temperature superconducting tape composite structure. The ultrasonic welding device uses a roller pressure head with an amplitude of 40% and a pressure of 4 bar.

[0058] Figure 3 This is a graph showing the relationship between the quench propagation velocity and the current in Example 1 of the composite structure and preparation method of a second generation high temperature superconducting tape of the present invention. Figure 3 As shown, the abscissa is the current and the ordinate is the quench propagation velocity. The quench propagation velocity of the second generation high temperature superconducting tape prepared by the above method is 138 cm / s under 70A conditions.

[0059] Example 2

[0060] This embodiment provides a composite structure and a preparation method of a second-generation high-temperature superconducting tape, comprising the following steps:

[0061] Step S1: The silver layer of the second-generation high-temperature superconducting tape to be composited has a thickness of 2 μm and a width of 12 mm, and the indium foil has a thickness of 3 μm and a width of 11.9 mm.

[0062] Step S2: Arrange two second generation high temperature superconducting tapes to be composited on the upper and lower sides of the indium foil respectively, with the silver layer 1 on the side of the second generation high temperature superconducting tape to be composited close to the superconducting layer 3 facing the indium foil.

[0063] Step S3: Using a roll-to-roll pre-composite process, a 7N tension is applied to the second generation high temperature superconducting tape to be composited, and no tension is applied to the indium foil. The first second generation high temperature superconducting tape to be composited, the indium foil and the second second generation high temperature superconducting tape to be composited are simultaneously passed through a pressure device to form a second generation high temperature superconducting tape pre-composite structure. The pressure device uses a roller pressure head with a pressure of 4 bar. The pressure device is respectively provided with slits at the front and rear, and the slit width is 12.01 mm.

[0064] Step S4: Using a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is passed through an ultrasonic welding device at a tape speed of 100 m / h to form a second-generation high-temperature superconducting tape composite structure. The ultrasonic welding device uses a roller pressure head with an amplitude of 50% and a pressure of 5 bar.

[0065] The second-generation high-temperature superconducting tape prepared by the above method has a quench propagation velocity of 135 cm / s under 70A conditions.

[0066] Example 3

[0067] This embodiment provides a composite structure and a preparation method of a second-generation high-temperature superconducting tape, comprising the following steps:

[0068] Step S1: The silver layer of the second-generation high-temperature superconducting tape to be composited has a thickness of 1 μm and a width of 2 mm, and the indium foil has a thickness of 1.5 μm and a width of 1.99 mm.

[0069] Step S2: Arrange two second generation high temperature superconducting tapes to be composited on the upper and lower sides of the indium foil respectively, with the silver layer 1 on the side of the second generation high temperature superconducting tape to be composited close to the superconducting layer 3 facing the indium foil.

[0070] Step S3: Using a roll-to-roll pre-composite process, a 2N tension is applied to the second generation high temperature superconducting tape to be composited, and no tension is applied to the indium foil. The first second generation high temperature superconducting tape to be composited, the indium foil and the second second generation high temperature superconducting tape to be composited are simultaneously passed through a pressure device to form a second generation high temperature superconducting tape pre-composite structure. The pressure device uses a roller pressure head with a pressure of 2 bar. The pressure device is provided with slits at the front and rear, and the slit width is 2.001 mm.

[0071] Step S4: Using a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is passed through an ultrasonic welding device at a tape speed of 10 m / h to form a second-generation high-temperature superconducting tape composite structure. The ultrasonic welding device uses a roller pressure head with an amplitude of 30% and a pressure of 3 bar.

[0072] The second-generation high-temperature superconducting tape prepared by the above method has a quench propagation velocity of 140 cm / s under 70A conditions.

[0073] Comparative Example 1

[0074] The difference between Comparative Example 1 and Example 1 is that the superconducting tape of Comparative Example 1 is not compounded. The second generation high temperature superconducting tape prepared by the above method has a quench propagation velocity of 10.1 cm / s under 70A.

[0075] Comparative Example 2

[0076] The difference between Comparative Example 2 and Example 1 is that the superconducting tape of Comparative Example 2 is not coated with a silver layer. The quench propagation velocity of the second generation high temperature superconducting tape prepared by the above method under the condition of 70A is 17.3 cm / s.

[0077] Comparative Example 3

[0078] The difference between Comparative Example 3 and Example 1 is that the thickness of the silver layer of the superconducting tape of Comparative Example 3 is 3 μm, and the thickness of the indium foil is 2 μm. Apart from this, the remaining steps are the same as those of Example 1. The second-generation high-temperature superconducting tape prepared by the above method has a quench propagation velocity of 13.6 cm / s under 70A conditions.

[0079] Comparative Example 4

[0080] The difference between Comparative Example 4 and Example 1 is that the thickness of the silver layer of the first superconducting tape to be composited in Comparative Example 4 is 1.4 μm, and the thickness of the silver layer of the second superconducting tape to be composited is 1.6 μm. In addition, the remaining steps are the same as those in Example 1. The second-generation high-temperature superconducting tape prepared by the above method has a quench propagation velocity of 41.8 cm / s under 70A conditions.

[0081] Comparative Example 5

[0082] The difference between Comparative Example 5 and Example 1 is that in step S3 of Comparative Example 5, a tension of 3N is applied to the indium foil. Other than that, the remaining steps are the same as those of Example 1. The second-generation high-temperature superconducting tape prepared by the above method may have the indium foil broken, and the second-generation high-temperature superconducting tape cannot be prepared.

[0083] In summary, the present invention adopts the composite structure and preparation method of the second-generation high-temperature superconducting tape, which can significantly improve the quench propagation speed of the second-generation high-temperature superconducting tape.

[0084] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0085] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A second generation high temperature superconducting tape composite structure, characterized in that: It comprises two second-generation high-temperature superconducting tapes to be composited and an indium foil, wherein the outer surfaces of the two second-generation high-temperature superconducting tapes to be composited are both coated with a silver layer; The indium foil is arranged between two second-generation high-temperature superconducting tapes to be composited, and the two second-generation high-temperature superconducting tapes to be composited are compositely connected with the indium foil to form a silver-indium alloy layer (2) as an intermediate layer and two composite second-generation high-temperature superconducting tapes located on both sides of the intermediate layer.

2. The second generation high temperature superconducting tape composite structure according to claim 1, characterized in that: The two composite second-generation high-temperature superconducting tapes are symmetrically arranged on both sides of the silver-indium alloy layer (2).

3. The second generation high temperature superconducting tape composite structure according to claim 1, characterized in that: The second generation high temperature superconducting tape to be composited and the indium foil are connected by ultrasonic welding.

4. The second generation high temperature superconducting tape composite structure according to claim 1, characterized in that: The composite second-generation high-temperature superconducting tape comprises a superconducting layer (3) and a metal base tape (5) arranged in layers, wherein the superconducting layer (3) is arranged on a side of the metal base tape (5) close to the silver-indium alloy layer (2); The second-generation high-temperature superconducting tape is coated with a silver layer (1) on all sides after the composite process, and the silver layers (1) on one side of the superconducting layer (3) in the two second-generation high-temperature superconducting tapes after the composite process are connected via a silver-indium alloy layer (2).

5. The second generation high temperature superconducting tape composite structure according to claim 4, characterized in that: A transition layer (4) is provided between the superconducting layer (3) and the metal base tape (5).

6. The second generation high temperature superconducting tape composite structure according to claim 4, characterized in that: The thickness ratio between the silver layer (1) between the superconducting layer (3) and the silver-indium alloy layer (2) and the silver layer (1) covering the side of the metal base tape (5) away from the superconducting layer (3) is 0.01-0.

2.

7. The second generation high temperature superconducting tape composite structure according to claim 1, characterized in that: The silver layer on the outer surface of the second-generation high-temperature superconducting tape to be composited is deposited using a multi-pass roll-to-roll technology, with the angles between the left outermost pass and the right outermost pass and the target plane being 15-30° and -15--30° respectively.

8. The second generation high temperature superconducting tape composite structure according to claim 1, characterized in that: The side surface of the second generation high temperature superconducting tape to be composited is completely covered by the silver layer without any exposed part, and the thickness of the silver layer on the side surface is 10-100nm.

9. A method for preparing a second-generation high-temperature superconducting tape composite structure, characterized in that: The method for preparing the second-generation high-temperature superconducting tape composite structure according to any one of claims 1 to 8 comprises the following steps: Step S1: selecting indium foil of corresponding specifications according to the specifications of the second-generation high-temperature superconducting tape to be composited; Step S2: arranging two second-generation high-temperature superconducting tapes to be composited on the upper and lower sides of the indium foil respectively; Step S3: using a roll-to-roll pre-combination process, the two second-generation high-temperature superconducting tapes to be composited and the indium foil are simultaneously passed through a pressure device to form a pre-combined second-generation high-temperature superconducting tape; Step S4: adopting a roll-to-roll composite process, the pre-compounded second-generation high-temperature superconducting tape is welded by an ultrasonic welding device to form a second-generation high-temperature superconducting tape composite structure.

10. The method for preparing the second generation high temperature superconducting tape composite structure according to claim 9, characterized in that: In step S1, the second generation high temperature superconducting tape to be composited has a thickness of 20-150 μm and a width of 2-12 mm; In the second generation high temperature superconducting tape to be composited, the thickness of the silver layer (1) on one side of the superconducting layer (3) and the thickness of the silver layer (1) on one side of the metal base tape (5) are both 1-2 μm, and the difference in thickness of the silver layer (1) on one side of the superconducting layer (3) of the two second generation high temperature superconducting tapes to be composited is -100-100 nm; The thickness of the indium foil is 0.5-1.0 μm thicker than the thickness of the silver layer (1) on one side of the superconducting layer (3) of the second-generation high-temperature superconducting tape to be composited, and the width is 0.01-0.1 mm narrower than the second-generation high-temperature superconducting tape to be composited; In step S2, the silver layer (1) on the side of the second generation high temperature superconducting tape to be composited close to the superconducting layer (3) is opposite to the indium foil; In step S3, a tension of 2-7N is applied to the second-generation high-temperature superconducting tape to be composited, and no tension is applied to the indium foil. The pressure device uses a roller pressure head with a pressure of 2-4 bar. Slits are respectively installed at the front and rear of the pressure device, and the width of the slit is 0.001-0.01mm wider than the second-generation high-temperature superconducting tape to be composited; In step S4, the ultrasonic welding device uses a roller pressure head, the amplitude of ultrasonic welding is 30%-50%, the pressure is 3-5 bar, and the tape travel speed of the roll-to-roll device is 10-100 m / h.

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