A transformer winding structure based on copper-aluminum eutectic plate and a wiring method thereof

Abstract

This invention relates to the field of power transformer manufacturing technology, and particularly to a transformer winding structure and its wiring method based on a copper-aluminum eutectic plate. The invention discloses a transformer winding structure based on a copper-aluminum eutectic plate, comprising a winding body formed by alternating layers and winding of a copper-aluminum eutectic material and an interlayer insulator. The copper-aluminum eutectic material includes a copper surface layer, an aluminum substrate, and a eutectic layer. The thickness of the eutectic layer is 300nm-500nm, and the main crystalline phases of the eutectic layer are Al2Cu and Al4Cu9. The interfacial bonding strength of the eutectic layer is ≥300MPa. This invention's transformer winding structure and wiring method based on a copper-aluminum eutectic plate fundamentally eliminates the risks of delamination and heat generation by forming a high-strength, non-brittle nano-eutectic layer at the copper-aluminum interface. While ensuring interface reliability, it fully leverages the lightweight and cost advantages of aluminum-based materials, and utilizes the surface copper to achieve reliable electrical connections.

Description

Technical Field

[0001] This invention relates to the field of power transformer manufacturing technology, and in particular to a transformer winding structure based on a copper-aluminum eutectic plate and its wiring method. Background Technology

[0002] In the field of power transformers, the low-voltage side windings carry extremely large currents. To optimize current distribution and enhance the ability to withstand short-circuit electrodynamic forces, foil winding structures are commonly used. Regarding the selection of conductive materials, pure copper windings offer excellent conductivity, but copper resources are scarce and have a high density, leading to high transformer costs and excessive weight. While pure aluminum windings offer advantages in cost and lightweight design, their lower conductivity often necessitates a significant increase in conductor cross-sectional area to achieve Level 1 energy efficiency standards, resulting in a dramatic increase in winding volume. Furthermore, when pure aluminum leads are connected to copper terminals, differences in material physical properties and oxide film issues can easily lead to defects such as high contact resistance and insufficient connection stability.

[0003] To combine the electrical conductivity of copper with the lightweight and low-cost properties of aluminum, the industry has proposed copper-aluminum composite plates. Traditional copper-aluminum composite plates typically use rolling and pressing processes to achieve a mechanical interlocking bond. However, this bonding method has fundamental technical drawbacks: its interfacial bonding strength is low, typically below 200 MPa, and during manufacturing and use, a thick, brittle intermetallic compound phase is easily formed at the interface. Under the alternating electromagnetic vibrations and thermal cycling shocks generated during long-term transformer operation, these brittle phases will initiate and propagate microcracks, eventually leading to interface delamination and peeling. Once delamination occurs at the copper-aluminum interface, it will trigger a series of serious electrical faults: a sharp increase in contact resistance, uncontrolled local temperature rise, accelerated aging of insulation materials, and even winding burnout.

[0004] Therefore, how to obtain a transformer winding structure that combines cost and lightweight advantages with the reliable conductive connection performance of copper, while avoiding delamination failure of the copper-aluminum interface due to insufficient bonding strength and brittle phase formation under alternating vibration and thermal cycling impact, is a technical problem that urgently needs to be solved in this field, and is also the core bottleneck for realizing the large-scale application of high-performance copper-aluminum composite windings. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a transformer winding structure and wiring method based on a copper-aluminum eutectic plate. By forming a high-strength, non-brittle nano-eutectic layer at the copper-aluminum interface, the risks of delamination and overheating are fundamentally eliminated. While ensuring interface reliability, the invention fully leverages the lightweight and cost advantages of aluminum-based materials, and utilizes the surface copper to achieve reliable electrical connections.

[0006] Therefore, the first objective of this invention is to provide a transformer winding structure based on a copper-aluminum eutectic plate.

[0007] The second objective of this invention is to provide a wiring method based on a copper-aluminum eutectic plate transformer winding structure.

[0008] To achieve the first objective of this invention, the technical solution of this invention provides a transformer winding structure based on a copper-aluminum eutectic plate, including a winding body, which is formed by alternating layers and winding of copper-aluminum eutectic material and interlayer insulator; wherein, the copper-aluminum eutectic material includes: a copper surface layer, an aluminum base body and a eutectic layer, the thickness of the eutectic layer is 300nm-500nm, the main crystalline phases of the eutectic layer are Al2Cu and Al4Cu9, and the interfacial bonding strength of the eutectic layer is ≥300MPa.

[0009] Compared with existing technologies, the technical effects achieved by this solution are as follows: This structure replaces the mechanical bonding interface of traditional rolled composite plates with a nano-eutectic layer, effectively avoiding the formation of thick and brittle phases. Under the long-term alternating electromagnetic vibration and thermal cycling impact of transformers, the interface will not undergo microscopic peeling or delamination, thus fundamentally eliminating the risk of increased contact resistance and local overheating caused by interface failure. At the same time, it retains the lightweight and low-cost advantages of the aluminum-based body and the reliable electrical connection performance of the surface copper.

[0010] In one technical solution of the present invention, two compensation structures are selected for configuration: thickness compensation type: the thickness of the copper-aluminum eutectic plate is increased by 30% compared with the pure copper foil winding of the same energy efficiency, while the number of winding turns remains unchanged; width compensation type: the axial width of the copper-aluminum eutectic plate is increased by 20% compared with the pure copper foil winding of the same energy efficiency, while the number of winding turns remains unchanged.

[0011] Compared with existing technologies, the technical effects achieved by this solution are as follows: through precise thickness or width compensation, the load loss of aluminum-based windings is reduced to a level comparable to that of pure copper windings, which can stably meet the national first-class energy efficiency standard. At the same time, since the density of aluminum is much lower than that of copper, the weight of the windings can be reduced by about 40%, achieving a balance between energy efficiency, cost and lightweighting.

[0012] In one technical solution of the present invention, the interlayer insulator is at least one of DMD insulating paper or epoxy prepreg material; the thickness of the interlayer insulator is 0.1mm-0.3mm; and the width of the interlayer insulator exceeds the width of the copper-aluminum eutectic material by 3mm-5mm on one side.

[0013] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: the selection and size setting of the interlayer insulation material ensures that the winding layers have sufficient electrical insulation strength and mechanical support capacity, while the overhanging part at the end can effectively prevent the risk of creepage caused by winding misalignment or edge electric field concentration, thereby improving the withstand voltage performance and long-term operational reliability of the winding.

[0014] To achieve the second objective of this invention, the technical solution of this invention provides a wiring method for a transformer winding structure based on a copper-aluminum eutectic plate using any of the above-mentioned technical solutions, comprising the following steps: S100, alternately layering and winding copper-aluminum eutectic material and interlayer insulator under constant tension to obtain a winding body; S200, connecting the winding lead end and the lead terminal by cold pressure welding, wherein the winding lead end and the lead terminal overlap to form an overlap area, and a plurality of cold pressure welding points are provided in the overlap area; S300, sequentially performing vacuum pressure impregnation and curing treatment on the completed winding body.

[0015] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: by replacing traditional high-heat-input welding with cold pressure welding, the burning of the surface copper layer and the softening or melting of the internal aluminum base are completely avoided. At the same time, the multi-point parallel cold pressure welding connection provides a larger effective contact area and reduces contact resistance. Furthermore, the subsequent impregnation and curing treatment further enhances the overall insulation performance and structural strength of the winding.

[0016] In one technical solution of the present invention, multiple groups of cold-pressed weld joints are provided, and the number of cold-pressed weld joints in each group is the same; a pre-reserved distance is reserved at the ends of the cold-pressed weld joints along the length direction. ; Reserve a distance along the edge of the cold-pressed weld joint in the width direction Center distance between adjacent cold-pressed weld points within the same group Group spacing between adjacent cold-pressed weld points The length and width of the cold-pressed weld point are l and w, respectively. The reserved distance at the end of the cold-pressed weld point along the length direction is e1, the reserved distance at the edge of the cold-pressed weld point along the width direction is e2, the center distance between adjacent cold-pressed weld points in the same group is p1, and the group distance between adjacent cold-pressed weld points is p2.

[0017] Compared to existing technologies, this technical solution achieves the following advantages: Conventional high-heat-input welding (such as argon arc welding and brazing) is prone to causing copper layer burn-off and aluminum base layer softening or melting due to heat. Therefore, the industry tends to use cold-press welding processes with low heat input. However, in existing cold-press welding connections, improper number and layout of weld points can still cause problems such as local current concentration, high contact resistance, and uneven stress, seriously affecting the long-term stable operation of transformers. The setting of these geometric parameters ensures that weld points do not get too close to the edge or end of the lap area, avoiding stress concentration and tearing risks in weak areas. At the same time, reasonable spacing within and between groups ensures uniform current distribution on the lap surface, preventing local current accumulation and local overheating.

[0018] In one technical solution of the present invention, the maximum number G of cold-pressed weld points that can be arranged along the length direction of the lap joint area is... max for: The number of cold-pressed weld joints is G, the length of the overlap area is L, and the number of cold-pressed weld joints in each group is q.

[0019] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: This formula provides a basis for the quantitative design of the number of solder joint groups, ensuring that as many solder joint groups as possible can be arranged within a limited overlap length to increase the total connection area, while avoiding insufficient effective connection or decreased mechanical strength due to excessively dense or sparse solder joints, thereby maximizing conductivity while ensuring connection reliability.

[0020] In one technical solution of the present invention, the cold-pressed weld points can be arranged in rows along the width direction of the lap joint area; when At that time, the maximum number of rows of cold-pressed weld joints m max for The number of rows of cold-pressed weld joints is m, the width of the overlap area is B, and the center distance between adjacent rows of cold-pressed weld joints is p. y .

[0021] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: When the overlap area is wide, the total number of weld points and the effective connection area can be further increased by increasing the number of rows. At the same time, the number of rows is controlled to not exceed a reasonable range to avoid material edge tearing or uneven stress caused by multiple rows. This provides a flexible optimization solution for weld point layout under different width conditions.

[0022] In one technical solution of the present invention, in S300, the curing temperature is 130℃-150℃ and the curing time is 3h-4h.

[0023] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: temperature control and time range ensure that the resin after vacuum pressure impregnation is fully cross-linked and cured to form a dense and high-strength insulation layer, while avoiding the adverse effects of excessive temperature or time on the copper-aluminum eutectic material interface, thus ensuring the overall electrical insulation performance and mechanical stability of the winding.

[0024] In one technical solution of the present invention, step S200 specifically includes: S210, cleaning the surface of the winding lead-out end and the surface of the lead terminal; S220, overlapping the winding lead-out end and the lead terminal to form an overlap area, and pressing and positioning it with a clamp; S230, applying pressure along the normal direction of the overlap area with a pressure head to form a pit as a cold-pressed solder joint, the pressing sequence being to first form the first solder joint group in the middle, and then form adjacent solder joint groups to both sides in sequence; S240, controlling the plastic deformation of the material at the cold-pressed solder joint, so that its maximum elongation is controlled at 80%-85%.

[0025] Furthermore, the pit is a depression with a rounded transition isosceles trapezoidal cross section.

[0026] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: The wiring method specifies the detailed operation steps of cold pressure welding. In these steps, the pressing sequence from the middle to both sides ensures that the force on the weld point gradually expands outward, reducing the tensile damage to the end material caused by cumulative deformation. The precise control of the elongation rate is sufficient to extrude the oxide film on the contact surface to achieve a pure physical solid connection, while avoiding excessive deformation that could lead to material cracking, thereby obtaining a cold pressure welded joint with low contact resistance and long-term stability.

[0027] The technical solution provided by this invention can achieve at least one of the following effects: (1) The present invention forms a eutectic layer with a thickness of 300nm-500nm at the copper-aluminum interface through a solid-liquid casting and rolling integrated process. The main crystal phases are Al2Cu and Al4Cu9, and the interface bonding strength is not less than 300MPa. It realizes atomic-level metallurgical bonding, effectively avoids the generation of thick and brittle phases in traditional rolled composite plates. Under the long-term alternating electromagnetic vibration and cold and hot cycle impact of the transformer, the interface will not delaminate or peel off, thereby fundamentally eliminating the risk of increased contact resistance and local overheating caused by interface failure, and greatly improving the operating reliability and service life of the winding. (2) By using a thickness compensation scheme or a width compensation scheme, that is, while keeping the number of turns unchanged, the thickness of the copper-aluminum eutectic plate is increased by 30% or the axial width is increased by 20% compared with the pure copper foil winding with the same energy efficiency, so that the load loss of the aluminum-based winding is reduced to a level comparable to that of the pure copper winding, which can stably meet the national first-level energy efficiency standard. At the same time, the density of aluminum is much lower than that of copper, and the weight of the winding can be reduced by about 40%, achieving a unity of high energy efficiency, lightweight and low cost. (3) Cold pressure welding is used to connect the winding lead-out end and the lead terminal, and the layout parameters such as the end reserved distance, edge reserved distance, center distance within the group and group spacing are specified, in conjunction with the pressing sequence from the middle to both sides and the control of plastic elongation. This method completely avoids the burning of the surface copper layer and the thermal softening of the internal aluminum base body caused by high heat input welding. At the same time, the optimized layout of multiple parallel connections ensures the uniform distribution of current on the lap surface, avoids local current concentration and uneven stress, and achieves extremely low and long-term stable contact resistance; (4) Further quantitative calculation formulas for the maximum number of groups and the maximum number of rows of weld points are provided, so that the total number of weld points can be scientifically designed under the given overlap length and width conditions, taking into account both the maximization of connection area and the protection of material edge strength. The insulation performance and structural strength of the overall winding are further enhanced, ensuring the mechanical and electrical stability of the transformer under short-circuit current and overload impact. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be discussed below. Obviously, the technical solutions described in conjunction with the accompanying drawings are only some embodiments of the present invention. For those skilled in the art, other embodiments and their accompanying drawings can be obtained based on the embodiments shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the transformer winding structure based on the copper-aluminum eutectic plate of the present invention; Figure 2 This is a schematic diagram of the copper-aluminum eutectic material structure of the present invention; Figure 3 This is a schematic diagram of the overlapping area of ​​the present invention.

[0030] Explanation of reference numerals in the attached figures: 1. Copper-aluminum eutectic material; 11. Copper surface layer; 12. Aluminum base; 13. Eutectic layer; 2. Interlayer insulator; 3. I-beam support bar; 4. Inner shaft space of winding; 5. Winding lead-out end; 6. Lead terminal; 7. Cold-pressed solder joint. Detailed Implementation

[0031] The technical solutions of various embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The following reference Figures 1 to 3 The technical solutions of some embodiments of the present invention are described below.

[0033]

Example 1

[0034] A transformer winding structure based on a copper-aluminum eutectic plate, wherein copper-aluminum eutectic material 1 is selected, and its microstructure is as follows. Figure 2 As shown: the surface layer is a copper layer 11, the interior is an aluminum-based body 12, and between the two is a nano-eutectic layer 13 with a thickness controlled between 300nm and 500nm. The main crystalline phases are Al2Cu and Al4Cu9, and the measured interfacial bonding strength is 320MPa.

[0035] A thickness compensation scheme is adopted: the thickness of the copper-aluminum eutectic material is 1.3mm (30% thicker than the 1.0mm pure copper foil of the same energy efficiency design), and the width is 400mm. The interlayer insulator 2 is made of DMD insulating paper with a thickness of 0.15mm, and its width exceeds the width of the copper-aluminum eutectic material 1 by 4mm on each side.

[0036] like Figure 1 As shown, a foil winding machine is used to alternately layer and wind copper-aluminum eutectic material 1 and interlayer insulator 2 under a constant tension of 0.6 MPa to form a cylindrical winding body. I-beam support bars 3 are set at the inner shaft space 4 of the winding to maintain structural stability. The number of winding turns is consistent with the pure copper scheme.

[0037] A wiring method based on a copper-aluminum eutectic plate transformer winding structure, specifically referring to... Figure 3 : S100. Copper-aluminum eutectic material and interlayer insulator are alternately layered and wound under constant tension to obtain the above winding structure. S210. Clean the surface of the copper layer of the copper-aluminum eutectic material winding lead 5 and the surface of the external lead 6 (selecting a pure copper busbar with a thickness of 1.5mm) to remove oil and oxide film. S220. Connect the winding lead 5 to the external lead 6 to form an overlap area, and use a clamp to press and position it. S230. Based on the length L and width B of the overlap area, design the layout of the cold-pressed weld points 7. This embodiment adopts a single-row, grouped, and symmetrical layout. Assume the weld point length l = 4mm, width w = 2mm, end clearance e1 = 1.5l = 6mm, edge clearance e2 = w = 2mm, center distance within a group p1 = 1.5l = 6mm, group spacing p2 = 3l = 12mm, and the number of weld points in each group q = 3. Calculate the maximum allowed number of groups according to the formula and actually arrange 3 groups of weld points. Use a special pressure head to apply pressure along the normal direction of the overlap area to form a recess with a rounded corner transition isosceles trapezoidal cross-section as the weld point 7. The pressing sequence is: first press the weld point group located in the middle of the overlap area, then press the remaining weld point groups symmetrically to both sides in sequence. S240. Control the depth of the pressure head to keep the maximum elongation of the plastic deformation of the material at the weld point at 82%. S300. Vacuum pressure impregnation is performed on the completed winding body in sequence, and then it is transferred into an oven and cured at 140°C for 3.5 hours.

[0038]

Example 2

[0039]

Example 3

[0040]

Example 4

[0041]

Example 5

[0042]

Example 6

[0043]

Example 7

[0044]

Example 8

[0045]

Example 9

[0046]

Example 10

[0047] Comparative Example 1 This embodiment refers to Embodiment 1, the difference being that: in S100, a copper-aluminum composite plate with a traditional rolling process is used to replace the solid-liquid casting-rolling integrated copper-aluminum eutectic material. The interface of this traditional composite plate is mechanically bonded, the interface bonding strength is 180MPa, and there is a brittle intermetallic compound layer with a thickness of more than 2μm at the interface.

[0048] Comparative Example 2 This embodiment refers to Embodiment 1, the difference being that in S100, pure copper foil is used instead of copper-aluminum eutectic material, with a thickness of 1.0 mm, while the other steps are the same.

[0049] Comparative Example 3 This embodiment refers to Embodiment 1, the difference being that in S100, pure aluminum foil is used instead of copper-aluminum eutectic material, with a thickness of 1.3 mm and a width of 400 mm, while the other steps are the same.

[0050] Comparative Example 4 This embodiment refers to Embodiment 1, the difference being that in S200, argon arc welding is used instead of cold pressure welding to connect the winding lead-out end and the lead terminal, the welding current is 80A, and the welding time is 2 seconds.

[0051] Comparative Example 5 This embodiment refers to Embodiment 1, the difference being that: in S200, the cold pressure welding points adopt a single row continuous ungrouped layout, with a total of 9 welding points, and the welding points are distributed at equal intervals. The group spacing is equal to the intra-group spacing, that is, p2=p1=6mm, and the other parameters remain unchanged.

[0052] Comparative Example 6 This embodiment refers to Embodiment 1, the difference being that in S200, the cold pressure welding sequence is to start from one end and press towards the other side, rather than pressing from the middle to both sides.

[0053] Comparative Example 7 This embodiment refers to Embodiment 1, except that in S200, the maximum elongation of the plastic deformation of the material at the weld point is controlled to be 70%.

[0054] Comparative Example 8 This embodiment refers to Embodiment 1, the difference being that in S200, the maximum elongation of the plastic deformation of the material at the weld point is controlled to be 95%.

[0055] Table 1

[0056] According to the test results in Table 1, the transformer winding structures based on copper-aluminum eutectic plates provided in Examples 1 to 10 exhibit contact resistance in the connection area. The contact resistance in Examples 1 to 4 is 16 μΩ to 25 μΩ, significantly lower than the 120 μΩ of the pure aluminum winding in Comparative Example 3 and the 95 μΩ of the argon arc welding in Comparative Example 4, and close to the 21 μΩ of the pure copper winding in Comparative Example 2. This indicates that the cold-pressed welding multi-point parallel layout of the present invention can achieve extremely low connection resistance. Regarding the temperature rise of the hottest spot of the winding under rated current, Examples 1 to 10 are all controlled between 76 K and 80 K, comparable to the 78 K of the pure copper winding in Comparative Example 2, and far lower than the 98 K of the pure aluminum winding in Comparative Example 3, the 105 K of the traditional composite plate in Comparative Example 1, and the 112 K of the argon arc welding in Comparative Example 4. This fully demonstrates that thickness compensation or width compensation schemes can enable aluminum-based windings to meet the temperature rise requirements of the first-level energy efficiency standard. Regarding vibration resistance reliability, after 200 hours of vibration testing, the contact resistance change rate of Examples 1 to 10 was only +2.8% to +6.5%, while the change rate of Comparative Example 1 was as high as +28%, Comparative Example 3 as high as +35%, and Comparative Example 4 as high as +42%. This indicates that the high-strength eutectic interface and optimized cold-press welding layout of the present invention can effectively resist the degradation of connection performance caused by alternating electromagnetic vibration. A comparison of Examples 1, 5, and 6 shows that increasing the end allowance distance and the center distance of the weld points within the group (Examples 5 and 6) leads to a slight increase in contact resistance and the change rate after vibration. This demonstrates that strictly adhering to the parameter range in the layout formula (e1≥1.5l, p1=1.5~2l) is crucial for maintaining optimal connection performance. A comparison of Examples 1 with Examples 7 and 8 shows that controlling the plastic elongation within the range of 80% to 85% yields good results, with the lowest change rate after vibration (+3.5%) at 80%. Excessively low elongation (Comparative Example 7, 70%) or excessively high elongation (Comparative Example 8, 95%) leads to increased contact resistance and decreased vibration resistance. Regarding thermal cycling resistance, Examples 1 to 10 showed 0% delamination after 200 thermal cycles, while Comparative Example 1 showed a delamination rate as high as 45% for the traditional composite plate, Comparative Example 3 showed a delamination rate of 38% for the pure aluminum winding, Comparative Example 4 showed a delamination rate of 52% due to embrittlement of the heat-affected zone in the argon arc welded section, and Comparative Example 8 showed 5% delamination due to microcracks caused by excessive elongation. This fully demonstrates that a nano-eutectic layer (mainly Al2Cu and Al4Cu9) with a thickness of 300nm to 500nm avoids the formation of traditional brittle phases, maintains interface integrity under alternating hot and cold environments, and fundamentally solves the industry problem of delamination failure in copper-aluminum composite structures. In summary, the embodiments of the present invention exhibit excellent performance in terms of interface bonding strength, connection conductivity, temperature rise control, vibration resistance, and thermal cycling resistance, achieving a balance between high energy efficiency, high reliability, lightweight design, and low cost.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims, not by the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A transformer winding structure based on a copper-aluminum eutectic plate, comprising a winding body, characterized in that, The winding body is formed by alternating layers and winding of copper-aluminum eutectic material (1) and interlayer insulator (2); The copper-aluminum eutectic material (1) includes: a copper surface layer (11), an aluminum substrate (12), and a eutectic layer (13). The thickness of the eutectic layer (13) is 300nm-500nm. The main crystal phases of the eutectic layer (13) are Al2Cu and Al4Cu9. The interfacial bonding strength of the eutectic layer (13) is ≥300MPa.

2. The transformer winding structure based on a copper-aluminum eutectic plate according to claim 1, characterized in that, Two compensation structures can be selected for configuration: Thickness compensation type: The thickness of the copper-aluminum eutectic plate is 30% thicker than that of the pure copper foil winding with the same energy efficiency, while the number of winding turns remains unchanged; Width compensation type: The axial width of the copper-aluminum eutectic plate is 20% wider than that of the pure copper foil winding with the same energy efficiency, while the number of winding turns remains unchanged.

3. The transformer winding structure based on a copper-aluminum eutectic plate according to claim 1, characterized in that, The interlayer insulator (2) is at least one of DMD insulating paper or epoxy prepreg material; The thickness of the interlayer insulator (2) is 0.1 mm to 0.3 mm; The width of the interlayer insulator (2) exceeds the width of the copper-aluminum eutectic material (1) by 3mm-5mm on one side.

4. A wiring method for a transformer winding structure based on a copper-aluminum eutectic plate as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S100. The copper-aluminum eutectic material (1) and the interlayer insulator (2) are alternately stacked and wound under constant tension to obtain the winding body; S200, the winding lead-out end (5) and the lead terminal (6) are connected by cold pressure welding. The winding lead-out end (5) and the lead terminal (6) overlap to form an overlap area. The overlap area is provided with a number of cold pressure welding points (7). S300. Vacuum pressure impregnation and curing treatment are performed on the completed winding body in sequence.

5. The wiring method according to claim 4, characterized in that, The cold-pressed weld points (7) are provided in multiple groups, and the number of cold-pressed weld points (7) in each group is the same; The cold-pressed weld joint (7) has a reserved distance at its end along the length direction. ; The cold-pressed weld point (7) has a reserved distance along its width. ; Center distance between adjacent cold-pressed weld points (7) within the same group ; Group spacing between adjacent cold-pressed weld points (7) ; The length and width of the cold-pressed weld point (7) are l and w, respectively. The end of the cold-pressed weld point (7) along the length direction is reserved as e1. The edge of the cold-pressed weld point (7) along the width direction is reserved as e2. The center distance between adjacent cold-pressed weld points (7) in the same group is p1. The group distance between adjacent cold-pressed weld points (7) is p2.

6. The wiring method according to claim 5, characterized in that, The maximum number G of cold-pressed weld points (7) that can be arranged along the length of the lap area max for: ； The number of cold-pressed weld points (7) is G, the length of the overlapping area is L, and the number of cold-pressed weld points (7) in each group is q.

7. The wiring method according to claim 5, characterized in that, The cold-pressed weld points (7) can be arranged in rows along the width direction of the overlap area; when At that time, the maximum number of rows m of the cold-pressed weld joints (7) max for ； Wherein, the number of rows of the cold-pressed weld points (7) is m, the width of the overlap area is B, and the center distance between adjacent rows of the cold-pressed weld points (7) is p. y .

8. The wiring method according to claim 4, characterized in that, In S300, the curing temperature is 130℃-150℃, and the curing time is 3h-4h.

9. The wiring method according to claim 4, characterized in that, Step S200 specifically includes: S210. Clean the surface of the winding lead-out end (5) and the surface of the lead terminal (6); S220. The winding lead-out end (5) and the lead terminal (6) are overlapped to form the overlap area, and clamped and positioned with a clamp. S230. Apply pressure along the normal direction of the lap area using a pressure head to form a pit as the cold-pressed weld point (7). The pressing sequence is to first form the first weld point group in the middle, and then form adjacent weld point groups to both sides in sequence. S240. Control the plastic deformation of the material at the cold-pressed weld point (7) so that its maximum elongation is controlled at 80%-85%.

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