Contact type thermal diode structure driven by memory alloy

Abstract

The invention provides a contact type thermal diode structure driven by memory alloy, and belongs to the technical field of thermal management. The thermal diode structure is composed of thermal diode periodic cell elements which are periodically arranged in a construction plane, and the construction plane is a plane perpendicular to the heat transfer direction. The thermal diode periodic cell is sequentially divided into a cold end structure, a heat insulation structure, a hot core structure, a heat conduction structure, a memory alloy deformation structure and a hot end structure from top to bottom. Under the forward heat transfer working condition, a low-thermal-resistance heat conduction channel is formed through phase transformation of a memory alloy deformation structure, and efficient heat transfer is achieved; under the working condition of reverse heat transfer, a high-heat-insulation heat passage is formed, and effective blocking of reverse heat flow is achieved. The material has excellent asymmetric heat conduction characteristics, can solve the problem that heat transfer is blocked, considers two contradictory performance requirements of forward heat conduction and reverse heat insulation of the structure, greatly improves the response efficiency to temperature change, is flexible in material selection, and can significantly widen the application range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thermal management, and relates to a contact type thermal diode structure driven by a memory alloy, in particular to a contact type thermal diode device based on a memory alloy combined with multiple materials, which is suitable for energy collection, advanced refrigeration, and heat dissipation of computing chips, and realizes dynamic switching of unidirectional and efficient heat transfer and reverse blocking. BACKGROUND

[0002] With the development of energy collection, advanced refrigeration and computing chips, the demand for efficient and intelligent heat flow control is increasingly prominent. Traditional thermal management solutions, such as heat sinks, liquid heat exchangers and thermal insulation plates, usually provide single thermal management performance of heat dissipation or heat preservation. However, in key applications such as thermal diode bridge power generation, Carnot refrigeration cycle and thermal logic computing, an intelligent heat control mechanism is needed, i.e. opening an efficient heat conduction channel when heat dissipation is needed, and blocking the heat flow when heat preservation or external heat backflow is needed.

[0003] In a thermal diode bridge power generation system, it is necessary to efficiently convert the oscillating heat source input, such as the day-night changing solar energy, into a unidirectional and stable temperature gradient to drive the thermoelectric generator, while preventing the heat from flowing back to the environment from the energy storage unit during the night or low temperature period, resulting in efficiency loss; in a Carnot refrigeration system, it is necessary to ensure that heat can only flow to the heat sink when the Carnot refrigeration material is in a hot state, and can only be absorbed from the cold source when it is in a cold state, to replace the oscillating fluid pumping system and realize efficient solid-state refrigeration cycle; in a thermal logic circuit, it is necessary to accurately control the heat flow direction to represent binary information and realize functions similar to electronic logic gates, such as AND, OR and NOT, to build a thermal-based computing system.

[0004] The device that realizes this unidirectional heat conduction function is called "thermal diode" or "thermal rectifier". At present, the existing thermal diode has many defects. Among them, the large thermal resistance is a common problem, which greatly hinders the heat transfer and reduces the working efficiency of the thermal diode. Slow response speed is also a significant disadvantage of the existing thermal diode, which cannot respond in time to realize the switching of heat transfer when facing rapid temperature changes, resulting in the inability to meet the needs in some temperature-sensitive application scenarios. The narrow application range is also an important problem of the existing thermal diode. The heat transfer efficiency of the thermal diode based on material phase change is limited by the phase change efficiency of the working medium, and the working medium relies on external forces such as gravity and capillary force for transmission, which is difficult to adapt to complex structural equipment scenarios. These defects seriously limit the application range and performance improvement of the thermal diode, and there is an urgent need for a new type of thermal diode to solve these problems.

[0005] Shape memory alloy, as a kind of smart material with unique shape memory effect, can undergo reversible shape change when subjected to temperature change. By applying shape memory alloy to the design of thermal diode, the control of heat transfer path can be realized by its response to temperature, which is expected to solve the problems of large thermal resistance, slow response speed and narrow application range of existing thermal diodes. By reasonably designing the structure and working mode of shape memory alloy, unidirectional and efficient heat transfer can be realized, and the performance and reliability of thermal diode can be improved. Therefore, the research on thermal diode based on shape memory alloy has important theoretical significance and practical application value. SUMMARY

[0006] In view of the problems existing in the prior art, the present application provides a multi-material thermal diode driven by a memory alloy, which utilizes the asymmetric thermal deformation behavior of the multi-material thermal diode when subjected to opposite heating directions to solve the problems of large thermal resistance, slow response speed and narrow application range of existing thermal diodes proposed in the background art.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0008] A contact type thermal diode structure driven by a memory alloy, the thermal diode structure 1 is composed of thermal diode periodic cells 3 arranged periodically in a construction plane 2; the construction plane 2 is a plane perpendicular to the heat transfer direction; the thermal diode periodic cell 3 is a smallest geometrically repeatable structure in the periodic arrangement.

[0009] The thermal diode periodic cell 3 is composed of a hot end structure 4, a cold end structure 5, a thermal core structure 6, a memory alloy deformation structure 7, a heat conduction structure 8, and a heat insulation structure 9. Specifically, the hot end structure 4 is a square plate structure at the bottom of the cell, and the upper edge of the upper surface is bonded to the lower edge of the upper surface of the heat conduction structure 8 through heat-conducting silicone, and the center of the upper surface is coaxially fixed to the lower end of the memory alloy deformation structure 7 through a two-component acrylic adhesive, which is the basic load-bearing and heat source access unit of the cell, can quickly receive external heat and transfer it to the connected components; the memory alloy deformation structure 7 is a double-temperature control spiral spring, coaxially arranged in the lower part of the cylindrical cavity in the middle of the heat conduction structure 8, and the upper end is coaxially bonded to the center of the lower surface of the thermal core structure 6 through a two-component acrylic adhesive, and the spring axis is coincident with the central axis of the thermal core structure 6 and the hot end structure 4, which can realize expansion and contraction with temperature change as the core driving structure; the heat conduction structure 8 is a hollow cube structure, which is sleeved outside the memory alloy deformation structure 7 and the thermal core structure 6, and the upper surface is fixed to the lower surface of the heat insulation structure 9 through heat-conducting silicone, and the cylindrical cavity inside can guide and limit the thermal core structure 6 and the memory alloy deformation structure 7, and at the same time, it can realize efficient heat conduction between the hot end structure 4 and the thermal core structure 6 as a high-heat-conduction bridge; the thermal core structure 6 is a cylindrical structure, coaxially embedded in the cavity of the heat conduction structure 8 and located above the memory alloy deformation structure 7, and the upper surface can rise and fall with the expansion and contraction of the memory alloy deformation structure 7, which is the core switch of the heat flow channel; the heat insulation structure 9 is a hollow square prism structure, arranged on the top of the heat conduction structure 8, and the upper surface is fixed to the lower edge of the cold end structure 5 through a two-component acrylic adhesive, and the inside downward square opening has a longer length than the outer diameter of the thermal core structure 6, which not only reserves space for the thermal core structure 6 to rise and fall, but also forms a solid heat insulation barrier when the thermal core and the cold end are separated; the cold end structure 5 is a square plate structure with the same size and shape as the hot end structure 4, located at the top of the cell, and the lower edge of the lower surface is bonded to the upper surface of the heat insulation structure 9 through a two-component acrylic adhesive, and the center of the lower surface can form a detachable contact with the upper surface of the thermal core structure 6, which is responsible for dissipating heat to the external heat dissipation environment. The above-mentioned position and connection relationship of the components form a coordinated cooperation, in the forward heat transfer condition, the hot end structure 4 receives heat and the temperature reaches the phase change critical temperature of the memory alloy deformation structure 7, the memory alloy deformation structure 7 expands and elongates, pushing the thermal core structure 6 to move upward along the cavity of the heat conduction structure 8, until it is in close contact with the center of the lower surface of the cold end structure 5, forming a low-thermal-resistance heat conduction path, realizing efficient heat transfer; in the reverse heat transfer condition, the temperature of the hot end cannot reach the phase change temperature of the memory alloy deformation structure 7, the memory alloy deformation structure 7 maintains the contraction state, the thermal core structure 6 and the cold end structure 5 form a gap, and at the same time, the heat insulation structure 9 plays a low-thermal-conduction barrier role, forming a high-thermal-resistance heat insulation path, effectively blocking the reverse heat flow.

[0010] Further, the hot end structure 4, as a panel structure of the thermal diode, its main function is to establish efficient heat conduction connection with the external heat source to be managed, so as to quickly and centrally receive the heat generated by the heat source; the cold end structure 5, also as a panel structure, its main function is to establish efficient heat conduction connection with the external heat dissipation environment or heat dissipation device, so as to effectively dissipate the heat conducted from the hot end. The thermal core structure 6, as a medium for transferring heat inside the thermal diode, when heat is transferred in the forward direction, the thermal core is in contact with the cold end, forming a high heat conduction channel, and when heat is transferred in the reverse direction, the thermal core is separated from the cold end, forming a high thermal resistance channel; the memory alloy deformation structure 7, as a driving structure of the thermal diode, its main function is that when the temperature exceeds the phase transition temperature, the memory alloy spring elongates, and when the temperature is below the phase transition temperature, the memory alloy spring returns to the original length. The heat conducting structure 8 is a material with high thermal conductivity, which serves as the main heat conducting and supporting structure; the heat insulation structure 9 is a material with low thermal conductivity, which serves as the main heat insulation structure.

[0011] Further, the thermal diode periodic cell 3 is sequentially divided from top to bottom into the cold end structure 5, the heat insulation structure 9, the thermal core structure 6, the heat conducting structure 8, the memory alloy deformation structure 7, and the hot end structure 4. In the initial state, the upper end of the heat conducting structure 8 and the upper end of the thermal core structure 6 are in the same plane, and the lower end of the heat conducting structure 8 and the memory alloy deformation structure 7 are in the same plane. The cold end structure 5, the heat insulation structure 9, the heat conducting structure 8, and the hot end structure 4 are connected to each other by a heat-conducting silicone adhesive or the like. The thermal core structure 6, the memory alloy deformation structure 7, and the hot end structure 4 are connected to each other by a two-component acrylic adhesive or the like. The cold end structure 5 and the hot end structure 4 use a material 10 with high thermal conductivity; the heat insulation structure 9 uses a material 11 with low thermal conductivity and a certain Young's modulus; the thermal core structure uses a material 12 with high thermal conductivity and low density; the heat conducting structure uses a material 13 with extremely high thermal conductivity and a certain Young's modulus; the memory alloy deformation structure uses a material 14 with heat-induced expansion shape memory capability;

[0012] Further, the geometric description parameters of the hot end structure 4, the cold end structure 5, the thermal core structure 6, the memory alloy deformation structure 7, the heat conducting structure 8, and the heat insulation structure 9 of the thermal diode periodic cell 3 are as follows:

[0013] The hot end structure 4 and the cold end structure 5 are two identical panel structures, and the panel is a square plate with equal length and width dimensions of a and a height dimension of b.

[0014] The thermal core structure 6 is a straight circular cylinder with a circular bottom surface and a diameter of c; the distance between the two bottom surfaces along the axis of the cylinder is d, and the axis is perpendicular to the bottom surface.

[0015] The memory alloy deformation structure 7 is a double-pass temperature control spiral spring, which has a spiral structure, a circular section of a single coil, an outer diameter e of the spring, and a spring wire diameter f; the thermal deformation characteristic has two forms, a contraction state at room temperature with a contraction length g as the shortest state; and an elongation state that starts to elongate when heated to a phase transition temperature and elongates to a maximum length h.

[0016] The heat conduction structure 8 is a hollow cuboid structure, which has a square bottom surface, a cylindrical through hole provided in the interior along the height direction. The outer cuboid has a square bottom surface with a length i and a width i, and a height j; the inner cylindrical hole has a diameter k, and the extension length of the through hole along the height direction is equal to the height j of the cuboid, that is, the through hole completely penetrates the cuboid, and the two ends penetrate the upper and lower bottom surfaces of the cuboid.

[0017] The heat insulation structure 9 is a hollow square prism structure, which has a square cross section with a central circular hole, an equal length and width of the outer contour defined as an outer side length l, an equal length and width of the inner hole defined as an inner side length m, and a dimension along the extension direction defined as a height n.

[0018] Further, a complete thermal diode structure 1 can be obtained by periodically arraying a thermal diode periodic cell 3 in a construction plane 2, by periodically repeating the arrangement of the single cell structure in space along the construction plane 2 to form an o x p array structure, where o and p represent the number of repeating units of the single cell in the horizontal and vertical directions, respectively.

[0019] Further, the periodic arrangement refers to a periodic arrangement in the form of a square in the construction plane 2.

[0020] Further, the hot end structure 4 and the cold end structure 5 serve as the main carriers of heat transfer, and can be selected from, but not limited to, carbon structural steel, aluminum alloy, copper alloy, etc., and need to have good heat conduction performance to quickly transfer heat from the external heat exchange object to the internal structure of the thermal diode, or to transfer heat from the internal structure of the thermal diode to the external heat exchange object.

[0021] Further, the thermal core structure 6 serves as a medium for transferring heat inside the thermal diode, and can be selected from, but not limited to, carbon structural steel, aluminum alloy, pure copper, etc., and needs to have good heat conduction performance to construct an efficient heat transfer channel under a forward heat transfer condition, and realize directional conduction of heat from the hot end to the cold end.

[0022] Further, the memory alloy deformation structure 7 is used as the driving structure of the thermal diode, controls the opening and closing of the heat flow channel, and is made of materials such as nickel-titanium alloy, copper-based alloy or iron-based alloy, but not limited to. The selected alloy material has good shape memory effect and thermal mechanical properties, can work stably in different temperature ranges, and the phase transition temperature can be accurately controlled by adjusting the alloy composition to adapt to different working temperature requirements.

[0023] Further, the heat conduction structure 8 is used as the main heat conduction structure of the thermal diode, and is made of materials such as carbon structural steel, aluminum alloy, pure copper, but not limited to, and needs to have excellent heat conduction and rigidity performance to conduct heat while supporting the structure.

[0024] Further, the heat insulation structure 9 is used as the main heat insulation structure of the thermal diode, and is made of materials such as glass fiber, aluminum silicate fiber, glass wool, but not limited to, and needs to have good heat insulation performance to prevent heat from being transferred in the opposite direction.

[0025] In the forward heat transfer condition, the temperature of the hot end is higher than that of the cold end, and the temperature of the hot end reaches and exceeds the phase transition critical temperature of the memory alloy driving unit; at this time, heat is transmitted from the hot end of the heat source side, the memory alloy driving unit is heated, the phase transition is triggered and the driving force is generated, the driving force drives the hot core structure to close to form a heat flow path, at this time, the heat first flows into the heat conduction structure 8 from the hot end structure 4, then is transmitted to the hot core structure 6 through the heat conduction structure 8, and finally is transmitted to the cold end structure 5 through the hot core structure 6 to complete heat exchange with the outside, thereby realizing efficient heat conduction.

[0026] In the reverse heat transfer condition, the temperature of the hot end is lower than that of the cold end; even if the external environment is in a high temperature state, the heat cannot be transmitted into the internal structure of the thermal diode due to the heat insulation barrier effect of the heat insulation structure 9, the memory alloy driving unit does not trigger phase transition and deformation, and always maintains the heat flow open circuit state, and the heat transfer is blocked.

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

[0028] (1) The thermal diode based on the asymmetric thermal deformation of the memory alloy under heating designed in the present application has excellent asymmetric heat conduction characteristics, and meets the performance requirements of structure forward heat conduction and reverse heat insulation which are contradictory to each other.

[0029] (2) In view of the problem of large thermal resistance of the existing thermal diode, the structure and material design are optimized to effectively improve the problem. In the forward heat transfer, the hot core structure and the cold end contact to form a high heat conduction channel, and the heat conduction structure adopts a material with extremely high thermal conductivity, which significantly reduces the heat transfer resistance; in the reverse heat transfer, the hot core and the cold end are separated, and the heat insulation structure with low thermal conductivity forms a high thermal resistance barrier, realizing efficient switching of heat transfer and solving the problem of heat transfer blockage.

[0030] (3) In view of the slow response speed of the existing thermal diode, the application takes the shape memory alloy deformation structure as the driving core, utilizes the unique shape memory effect, quickly extends when the temperature exceeds the phase transition temperature, and quickly restores the original length when the temperature is below the phase transition temperature, can quickly drive the thermal core structure and the cold end structure to realize contact or separation, thereby rapidly switching the heat conduction state, and greatly improving the response efficiency to temperature change.

[0031] (4) In view of the narrow application range of the existing thermal diode, the application breaks away from the dependence on external forces such as gravity and capillary force, and realizes the function through the shape memory characteristics of the shape memory alloy and the stable connection of multiple materials. At the same time, the material selection is flexible, which can adapt to complex structure scenes from large-scale equipment such as solar collectors to high-precision equipment such as electronic device heat dissipation, thereby significantly widening the application range. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a thermal diode structure schematic diagram based on shape memory alloy combined with multiple materials asymmetric thermal deformation.

[0033] Figure 2 is a thermal diode cell structure schematic diagram based on shape memory alloy combined with multiple materials asymmetric thermal deformation.

[0034] Figure 3 is a schematic diagram of the same cold end and hot end plate structure.

[0035] Figure 4 is a thermal core structure schematic diagram.

[0036] Figure 5 is a memory alloy double-travel temperature control spiral spring structure schematic diagram. Among them, Figure 5 (a) is a memory alloy spiral spring structure schematic diagram in a contracted state at room temperature; Figure 5 (b) is a memory alloy spiral spring structure schematic diagram in an elongated state at high temperature;

[0037] Figure 6 is a heat conduction structure schematic diagram.

[0038] Figure 7 is a heat insulation structure schematic diagram.

[0039] Figure 8 is a thermal mechanical response result comparison of the thermal diode structure periodic cell structure based on shape memory alloy combined with multiple materials asymmetric thermal deformation under 85℃ temperature load in the forward direction and 85℃ temperature load in the reverse direction. Figure 8 (a) is a curve graph of the temperature change with time on one side of the cold end temperature load when the thermal diode periodic cell structure is heated in the forward direction; Figure 8(b) is a graph of the time variation of the temperature of the hot end of the thermode under a temperature load when the thermode is heated in the reverse direction.

[0040] Figure 9 (b) is a graph of the time variation of the temperature of the hot end of the thermode under a temperature load when the thermode is heated in the reverse direction.

[0041] Figure 10 (b) is a graph of the time variation of the temperature of the hot end of the thermode under a temperature load when the thermode is heated in the reverse direction.

[0042] Figure: 1 is a schematic diagram of a thermode structure based on a memory alloy combined with asymmetric thermal deformation of a multi-material under heating; 2 is a construction plane; 3 is a thermode periodic cell; 4 is a hot end structure; 5 is a cold end structure; 6 is a hot core structure; 7 is a memory alloy deformation structure; 8 is a heat conduction structure; 9 is a heat insulation structure. DETAILED DESCRIPTION

[0043] In order to fully illustrate the present application, further detailed description will be made in combination with the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, but not to limit the present application.

[0044] Referring to Figures 1-10 , the present application provides a thermode structure based on a memory alloy combined with asymmetric thermal deformation of a multi-material under heating 1, which is composed of thermode periodic cells 3 arranged periodically in a construction plane 2. The geometric dimensions of the thermode periodic cell 3 are as follows: the length and width dimensions of the hot end structure 4 and the cold end structure 5 are equal, a = 26 mm, and the height dimension is b = 1 mm; the bottom surface diameter of the hot core structure 6 is c = 20 mm, and the height dimension is d = 18 mm; the geometric configuration of the memory alloy deformation structure 7 is a spiral winding structure, the cross section of a single coil is circular, the outer diameter of the spring is e = 17 mm, and the wire diameter of the spring is f = 1 mm, and the thermal deformation characteristics have two forms, a contraction state at room temperature with a contraction length of g = 12 mm in the shortest state, and an elongation state that starts to elongate when heated to the phase transition temperature, and the elongation to the longest length is h = 22 mm; the external cuboid of the heat conduction structure 8 has a length and width of i = 26 mm, and a height of j = 30 mm; the internal cylindrical hole has a diameter of k = 20 mm, and the extension length of the through hole along the height direction is equal to the height of the cuboid j = 30 mm, i.e. the through hole completely penetrates the cuboid, and the two ends penetrate the upper and lower bottom surfaces of the cuboid respectively. The heat insulation structure 9 is a hollow square prism structure, the cross section is a square with a central circular hole, the length and width of the outer contour are equal, defined as the outer side length l = 26 mm; the length and width of the inner hole are equal, defined as the inner side length m = 22 mm, and the dimension along the extension direction is defined as the height n = 10 mm.

[0045] In this embodiment, the hot end structure 4 and cold end structure 5 are made of carbon structural steel and can be manufactured using machining technology; the hot core structure 6 is made of aluminum alloy and can be manufactured using machining technology; the shape memory alloy deformation structure 7 is made of nickel-titanium alloy; the thermally conductive structure 8 is made of pure copper and can be manufactured using machining technology; and the thermal insulation structure 9 is made of glass fiber and can be manufactured using machining technology.

[0046] The specific assembly process is as follows: The lower end of the shape memory alloy deformable structure 7 is bonded to the central area of ​​the hot end structure 4 using a two-component acrylic adhesive, and the upper end is bonded to the central area of ​​the hot core structure 6 using a two-component acrylic adhesive. The assembly is then cured at room temperature for 24 hours to ensure that the spring axis, the central axis of the hot end structure, and the axis of the hot core structure coincide. The upper end of the hot end structure 4 is bonded to the lower end of the heat-conducting structure 8 using a two-component acrylic adhesive, the upper end of the heat-conducting structure 8 is bonded to the lower end of the heat insulation structure 9 using a two-component acrylic adhesive, and the upper end of the heat insulation structure 9 is bonded to the lower end of the cold end structure 5 using a two-component acrylic adhesive. The assembly is then cured at room temperature for 24 hours to ensure that the outer surfaces of the hot end structure 4, the heat-conducting structure 8, the heat insulation structure 9, and the cold end structure 5 coincide.

[0047] This embodiment verifies the performance of this thermal diode through finite element numerical simulation. Details are as follows:

[0048] The initial temperature of thermal diode structure 1 is 25℃. When thermal diode structure 1 is in a forward heat transfer condition, i.e., when an 85℃ load is applied to the hot end, the output temperature response is on the unloaded side. The increase in the hot end temperature causes the shape memory alloy deformation structure 7 to reach the phase transition trigger temperature, such as... Figure 9 As shown in the curve, the temperature exceeds 60℃ in about 10 seconds, driving the heat-conducting structure to quickly close the contact. The cold end temperature rapidly rises from the initial 25℃ to over 80℃ within 30 seconds and tends to stabilize, demonstrating efficient forward heat conduction capability. However, in the reverse heat transfer condition, with an 85℃ load applied to the cold end, monitoring the temperature response on the unloaded side, the shape memory alloy deformation structure 7 remains unchanged because it has not reached the phase transformation threshold temperature. The heat-conducting structure remains separated, and heat can only be slowly conducted through air gaps or insulation structures. Figure 10 As shown, the original hot end temperature only slightly increased from 25℃ to 25.6℃ within 100 seconds, demonstrating highly efficient reverse heat insulation capability. The difference in the temperature-time curves directly verifies the core performance of this thermal diode, which achieves unidirectional heat transfer with fast forward heat conduction and strong reverse barrier based on the shape memory alloy phase change driving mechanism. Its behavior is highly consistent with the structural design principle.

[0049] The above embodiments are only used to express the implementation of the present application, and cannot be understood as the limitation of the patent scope of the present application. Other changes and improvements can be made by those skilled in the art within the concept of the present application, which are all within the protection scope of the present application. The components not explicitly described in the embodiments can be realized by the prior art.

Claims

1. A contact thermode structure driven by a memory alloy, characterized in that, The thermal diode structure (1) is composed of thermal diode periodic cells (3) arranged periodically in a construction plane (2); the construction plane (2) is a plane perpendicular to the heat transfer direction; the thermal diode periodic cell (3) is a minimum geometric repeatable structure in the periodic arrangement; the thermal diode periodic cell (3) comprises a hot end structure (4), a cold end structure (5), a thermal core structure (6), a memory alloy deformation structure (7), a heat conduction structure (8), and a thermal insulation structure (9); specifically: The hot end structure (4) is at the bottom, and the upper end surface edge region thereof is connected with the lower end surface edge of the heat conduction structure (8), and the upper end surface center region thereof is coaxially fixed with the lower end of the memory alloy deformation structure (7); the memory alloy deformation structure (7) is a double-pass temperature control spiral spring, which is coaxially arranged in the lower part of the cylindrical cavity in the middle part of the heat conduction structure (8), and the upper end thereof is coaxially bonded with the center of the lower end surface of the thermal core structure (6), and serves as a core driving structure to realize expansion and contraction with temperature change; the heat conduction structure (8) is a hollow cubic structure, which is sleeved outside the memory alloy deformation structure (7) and the thermal core structure (6), and the upper end surface thereof is fully attached and fixed with the lower end surface of the thermal insulation structure (9); the thermal core structure (6) is a cylindrical structure, which is coaxially embedded in the cavity of the heat conduction structure (8) and located above the memory alloy deformation structure (7), and the upper end surface thereof can realize lifting with the expansion and contraction of the memory alloy deformation structure (7); the thermal insulation structure (9) is a hollow square prism structure, which is arranged on the top of the heat conduction structure (8), and the upper end surface thereof is fixed with the lower end surface edge of the cold end structure (5), and reserves space for the lifting of the thermal core structure (6); the cold end structure (5) is the same in size and shape as the hot end structure (4), and is located at the top, and the lower end surface edge thereof is connected with the upper end surface of the thermal insulation structure (9), and the lower end surface center thereof forms a separable contact with the upper end surface of the thermal core structure (6), and is used for dissipating heat to the external heat dissipation environment.

2. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, In the thermal diode periodic cell (3), from top to bottom, the cold end structure (5), the thermal insulation structure (9), the thermal core structure (6), the heat conduction structure (8), the memory alloy deformation structure (7), and the hot end structure (4) are sequentially arranged, wherein in the initial state, the upper end of the heat conduction structure (8) and the upper end of the thermal core structure (6) are in the same plane, and the lower end of the heat conduction structure (8) and the memory alloy deformation structure (7) are in the same plane.

3. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, In the thermal diode periodic cell (3), specifically: The hot end structure (4) is a square plate structure, the upper end surface edge region thereof is bonded with the lower end surface edge of the heat conduction structure (8) through heat-conducting silicone, and the upper end surface center region thereof is coaxially fixed with the lower end of the memory alloy deformation structure (7) through a two-component acrylic adhesive, which is a basic bearing and heat source access unit of the cell, and is used for receiving external heat source heat and transferring to the connected components; The upper end of the memory alloy deformation structure (7) is coaxially bonded with the lower end surface center of the thermal core structure (6) through a two-component acrylic adhesive, and the spring axis is coincided with the central axis of the thermal core structure (6) and the hot end structure (4); The upper end surface of the heat conduction structure (8) is fixed by full bonding with the lower end surface of the heat insulation structure (9) through heat-conducting silica gel, and the internally penetrating cylindrical cavity can play a guiding and limiting role on the heat core structure (6) and the memory alloy deformation structure (7), and simultaneously serve as a high-heat-conducting bridge to realize high-efficiency heat conduction between the heat end structure (4) and the heat core structure (6). The upper end surface of the heat insulation structure (9) is fixed by the edge of the lower end surface of the cold end structure (5) through double-component acrylic adhesive, and the internal downward square opening has a longer side than the outer diameter of the heat core structure (6), which not only reserves space for the lifting of the heat core structure (6), but also forms a solid heat insulation barrier when the heat core and the cold end are separated. The cold end structure (5) is a square plate structure with the same size and shape as the heat end structure (4), and the edge of the lower end surface is bonded to the upper end surface of the heat insulation structure (9) by double-component acrylic adhesive.

4. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, The heat diode periodic cell (3) comprises a heat end structure (4), a heat conduction structure (8), a heat core structure (6), a memory alloy deformation structure (7) and a heat insulation structure (9). In the forward heat transfer condition, the temperature of the heat end is higher than that of the cold end; the heat end structure (4) receives heat and makes the temperature reach the phase change critical temperature of the memory alloy deformation structure (7), the memory alloy deformation structure (7) undergoes phase change and elongation to generate driving force, which pushes the heat core structure (6) to move upward along the cavity of the heat conduction structure (8) until it is in close contact with the center of the lower end surface of the cold end structure (5), forming a low-thermal-resistance heat conduction path to realize high-efficiency heat transfer. In the reverse heat transfer condition, the temperature of the heat end is lower than that of the cold end; the temperature of the heat end cannot reach the phase change temperature of the memory alloy deformation structure (7), the memory alloy deformation structure (7) maintains the contraction state, the heat core structure (6) and the cold end structure (5) form a gap, and the heat insulation structure (9) plays a low-thermal-conductivity barrier role, forming a high-thermal-resistance heat insulation path to maintain the heat flow circuit breaking state and effectively block the reverse heat flow.

5. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, The low-thermal-resistance heat conduction path in the forward heat transfer condition is that the heat flow first flows into the heat conduction structure (8) from the heat end structure (4), is transferred to the heat core structure (6) through the heat conduction structure (8), is transferred to the cold end structure (5) through the heat core structure (6), and is exchanged with the outside to realize high-efficiency heat conduction.

6. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, A complete heat diode structure (1) can be obtained by periodically arraying a heat diode periodic cell (3) in a construction plane (2), and the single cell structure is periodically arranged in space along the construction plane (2) to form an o×p array structure, wherein o and p respectively represent the number of repeated units of the single cell in the transverse and longitudinal directions.

7. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, The periodic arrangement refers to a regular quadrilateral periodic arrangement in the construction plane (2).

8. The contact thermode structure driven by a memory alloy according to claim 1, characterized in that, The materials of the parts are as follows: The heat end structure (4) and the cold end structure (5) are the main carriers for heat transfer, and the materials thereof are carbon structural steel, aluminum alloy, copper alloy or other materials with good heat conduction performance; The heat core structure (6) is an internal heat transfer medium, and the material thereof is carbon structural steel, aluminum alloy, pure copper or other materials with good heat conduction performance; The memory alloy deformation structure (7) is a driving structure of the heat diode, which controls the opening and closing of the heat flow channel, and the material thereof is nickel-titanium alloy, copper-based alloy or iron-based alloy material; The heat-conducting structure (8) is the main heat-conducting structure of the heat diode, and is made of carbon structural steel, aluminum alloy, pure copper or other materials with good heat-conducting performance and rigidity. The heat-insulating structure (9) is the main heat-insulating structure of the heat diode, and is made of glass fiber, aluminum silicate fiber, glass wool or other materials with heat-insulating performance, so as to prevent heat from being reversely transferred.

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