Quasi-crystal-based solid-state composite heat conduction material, solid-state composite thermal diode and preparation method

Abstract

The invention relates to the technical field of heat management of new energy automobiles, in particular to a quasi-crystal-based composite heat conduction material, a solid-state composite thermal diode and a preparation method. The composite heat conduction material is of a structure with at least two layers and comprises a quasi-crystal material base body layer and a thermoelectric material layer. Wherein the material of the quasi-crystal material matrix layer is an Al-Cu-Fe-based quasi-crystal material, and the material of the thermoelectric material layer is a Cu-Ag-Se-based thermoelectric material; the quasi-crystal material has a regular 20-surface symmetry; under the condition of heat conduction, an asymmetric thermal resistance network structure is arranged between the quasi-crystal material matrix layer and the thermoelectric material layer. The composite heat conduction material can form an asymmetric thermal resistance network structure through the characteristics that the thermal conductivity of the quasicrystal material matrix layer is positively correlated with the temperature and the thermal conductivity of the thermoelectric material layer is negatively correlated with the temperature, and the asymmetric thermal resistance network structure can improve the thermal rectification ratio of the thermal composite heat conduction material.

Description

Technical Field

[0001] The present application relates to the field of thermal management technology for new energy vehicles, and in particular to a quasi-crystal-based solid-state composite thermal conductive material, a solid-state composite thermal diode, and a preparation method thereof. Background Art

[0002] Thermal diodes can regulate the direction of heat flow. Their principle is that forward heat flow is conducted, while reverse heat flow is significantly suppressed, similar to the rectification effect of an electronic diode on current. This phenomenon is called the thermal rectification effect. This thermal rectification effect allows thermal diodes to achieve directional regulation of heat flow. Therefore, thermal diodes can effectively improve the heat dissipation performance of batteries, optimize temperature distribution, avoid overheating and overcooling, and thus improve the battery's charge and discharge efficiency and service life. In order to achieve the thermal rectification effect, it is crucial to develop composite thermal conductive materials for thermal diodes.

[0003] Currently, the thermal rectification of composite thermal conductive materials of thermal diodes is relatively poor. Summary of the Invention

[0004] The present application provides a quasi-crystal-based composite thermal conductive material, a solid-state composite thermal diode, and a preparation method thereof, in order to solve the following technical problems: providing a composite thermal conductive material with a good thermal rectification ratio.

[0005] In a first aspect, an embodiment of the present application provides a quasi-crystal-based solid-state composite thermal conductive material, wherein the composite thermal conductive material has at least a two-layer structure, including: a quasi-crystal material matrix layer and a thermoelectric material layer; wherein the material of the quasi-crystal material matrix layer is an Al-Cu-Fe based quasi-crystal material, the quasi-crystal material has a regular icosahedral symmetry, and the material of the thermoelectric material layer is a Cu-Ag-Se based thermoelectric material; under the condition of heat conduction, an asymmetric thermal resistance network structure is present between the quasi-crystal material matrix layer and the thermoelectric material layer.

[0006] Optionally, the number of Al, Cu and Fe atoms in the Al-Cu-Fe based quasi-crystalline material satisfies: 61<[Al]<64, 23<[Cu]<27, 11<[Fe]<13, wherein [Al] is the number of Al atoms, [Cu] is the number of Cu atoms, and [Fe] is the number of Fe atoms.

[0007] Optionally, the Al-Cu-Fe based quasi-crystalline material is selected from the following: Al 61.5 Cu 26.5 Fe 12 、Al 62 Cu 25.5 Fe 12.5 、Al 63.2 Cu 24.2 Pt 0.9 Fe11.3 and Al 63.2 Cu 23.8 Pt 1.7 Fe 11.3 .

[0008] Optionally, the Cu-Ag-Se based thermoelectric material contains Cu, Ag and Se, wherein the number of atoms of Cu, Ag and Se is 1.

[0009] Optionally, the Cu-Ag-Se based thermoelectric material is selected from the following: CuAgSe, Ni 0.02 CuAgSe and Zn 0.02 CuAgSe.

[0010] Optionally, the thickness L1 of the quasi-crystalline material matrix layer and the thickness L2 of the thermoelectric material layer satisfy the relationship: 10 mm ≤ L1 + L2 ≤ 200 mm, and L1:L2 = x:(1-x), where x is 0.6 to 0.8.

[0011] Optionally, the quasi-crystalline material matrix layer and the thermoelectric material layer have the same projected area in the thickness direction.

[0012] Optionally, the composite thermally conductive material further includes a thermally conductive coating layer, and the thermally conductive coating layer is provided between the quasi-crystalline material matrix layer and the thermoelectric material layer.

[0013] In a second aspect, an embodiment of the present application provides a method for preparing the composite thermally conductive material according to the first aspect, the method comprising:

[0014] The metal powder of the Al-Cu-Fe based quasi-crystalline material is sequentially subjected to press forming, arc melting, first sintering and polishing to obtain a quasi-crystalline material matrix layer with a flat interface;

[0015] The metal powder of the Cu-Ag-Se based thermoelectric material is sequentially subjected to press forming, arc melting, second sintering and polishing to obtain a thermoelectric material layer with a smooth interface;

[0016] The quasi-crystalline material matrix layer and the thermoelectric material layer are butted together at a flat interface to obtain a solid composite thermal conductive material.

[0017] Optionally, the first sintering temperature T01 satisfies: T11-T01=180°C to 220°C, where T11 represents the melting point of the metal element with the lowest melting point in the Al-Cu-Fe based quasi-crystalline material; or

[0018] The second sintering temperature T02 satisfies: T12-T02=180°C to 220°C, where T12 represents the melting point of the metal element with the lowest melting point in the Cu-Ag-Se based thermoelectric material.

[0019] In a third aspect, an embodiment of the present application provides a quasi-crystal-based solid-state composite thermal diode, comprising a thermal conductor and a columnar composite thermal conductive material according to the first aspect.

[0020] Optionally, the solid-state composite thermal diode further includes a radiation shielding layer, and the radiation shielding layer is disposed around the outer periphery of the composite thermal conductive material.

[0021] Optionally, the distance between the inner surface of the radiation shielding layer and the outer surface of the composite thermally conductive material is less than or equal to the radius of the composite thermally conductive material; and / or,

[0022] The thickness of the radiation shielding layer is 1 mm to 1.5 mm.

[0023] In a fourth aspect, an embodiment of the present application provides a method for preparing the solid-state composite thermal diode described in the third aspect, the method comprising:

[0024] Obtaining the columnar composite thermally conductive material;

[0025] connecting two heat conductors to two opposite heat conducting ends of the composite heat conducting material to obtain a composite heat diode core;

[0026] A radiation shielding layer is disposed around the outer periphery of the composite thermal diode core to obtain a solid-state composite thermal diode.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The present invention provides a quasi-crystal-based solid-state composite thermal conductive material having at least two layers, including a quasi-crystal material matrix layer and a thermoelectric material layer. The Al-Cu-Fe-based quasi-crystal material has regular icosahedral symmetry, and the electronic density of states of the Al-Cu-Fe-based quasi-crystal material has a pseudo-energy gap, which makes the thermal conductivity of the quasi-crystal material matrix layer positively correlated with temperature. The thermoelectric material layer is a Cu-Ag-Se-based thermoelectric material. The Cu-Ag-Se-based thermoelectric material has a metallic phase at low temperatures and a semiconducting phase at high temperatures. This phase change property makes the thermal conductivity of the thermoelectric material layer negatively correlated with temperature. When the solid-state composite thermal conductive material is in thermal conduction, the combination of this positive and negative correlation between thermal conductivity and temperature results in an asymmetric thermal resistance network structure between the quasi-crystal material matrix layer and the thermoelectric material layer. Specifically, in the case of forward heat conduction, this asymmetric thermal resistance network structure can reduce the overall thermal resistance of the composite thermal conductive material, thereby enhancing the forward heat conduction effect of the composite thermal conductive material. In the case of reverse heat conduction, this asymmetric thermal resistance network structure can enhance the overall thermal resistance of the composite thermal conductive material to hinder the reverse heat conduction effect of the composite thermal conductive material. By enhancing the forward heat conduction effect and hindering the reverse heat conduction effect, the rectification ratio of the thermal composite thermal conductive material is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 A schematic structural diagram of a quasi-crystal-based solid-state composite thermal conductive material provided in an embodiment of the present application;

[0032] Figure 2 A schematic structural diagram of a quasi-crystal-based solid composite thermally conductive material containing a thermally conductive coating provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of a structure for preparing a solid-state composite thermal diode provided in an embodiment of the present application;

[0034] Figure 4 A schematic flow chart of a method for preparing a composite thermally conductive material provided in an embodiment of the present application;

[0035] Figure 5A schematic flow chart of a method for preparing a solid-state composite thermal diode provided in an embodiment of the present application;

[0036] Figure 6 The characterization of a quasi-crystal-based solid-state composite thermal diode and a thermal rectification ratio change curve provided in Example 1 of the present application, wherein: Figure 6 (a) XRD patterns of the quasi-crystalline material matrix layer and the thermoelectric material layer provided in Example 1 of the present application; Figure 6 (b) is a graph showing the temperature dependence of thermal conductivity of the quasi-crystalline material matrix layer and the thermoelectric material layer provided in Example 1 of the present application; Figure 6 (c) is a graph showing a change in the thermal rectification ratio of the solid-state composite thermal diode provided in Example 1 of the present application under different conditions of x;

[0037] Figure 7 This is a diagram showing the thermal rectification simulation experiment results of the solid-state composite thermal diode provided in this application. Figure 7 (a) is a diagram showing the thermal rectification simulation results of the solid-state composite thermal diode provided in Example 1 of the present application; Figure 7 (b) is a graph showing the forward heat and reverse heat results of the solid-state composite thermal diodes of Example 1 and Comparative Examples 2 to 7; Figure 7 (c) is a graph showing changes in the thermal rectification ratio of Example 1 and Comparative Examples 2 to 7 of the present application;

[0038] Among them, 1-quasi-crystalline material matrix layer, 2-thermoelectric material layer, 3-thermal conductor, 4-radiation shielding layer, 5-thermal conductive coating layer. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range; for example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited number (fractional or integer) within the indicated range.

[0041] As used herein, the terms "including," "comprising," and the like mean "including but not limited to." Relational terms such as "first" and "second" are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. "And / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "plurality" means two or more; "at least one," "at least one of the following," or similar expressions, refers to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c," or "at least one of a, b, and c," can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural. "Parts" notation, such as parts by weight and parts by mass, indicates the proportional relationship between components. In this article, the parameters described by ratio should be understood as the first term of the proportional formula, in the order in which they are described, and the proportional figures should be understood as the second term. For example, if the mass ratio of substances A, B, and C is 1:2:3, then substances A, B, and C should correspond to the proportional figures in the proportional formula in the order in which they are described, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0042] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0043] Figure 1 The following is a schematic structural diagram of a quasi-crystal-based composite thermal conductive material provided by an embodiment of the present application;

[0044] like Figure 1 As shown, an embodiment of the present application provides a quasi-crystal-based solid-state composite thermal conductive material, which has at least a two-layer structure, including: a quasi-crystal material matrix layer 1 and a thermoelectric material layer 2; wherein, the material of the quasi-crystal material matrix layer 1 is an Al-Cu-Fe-based quasi-crystal material, and the Al-Cu-Fe-based quasi-crystal material has a regular icosahedral symmetry, and the material of the thermoelectric material layer 2 is a Cu-Ag-Se-based thermoelectric material; under the condition of heat conduction, an asymmetric thermal resistance network structure is present between the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2.

[0045] It should be noted that quasicrystals are special solid materials with long-range order but non-periodic structure; the main characteristics of quasicrystals are that they include a long-range ordered structure similar to periodicity and rotational symmetry that is not allowed by crystals, such as 5-, 8-, 10- and 12-fold symmetry. The icosahedral quasicrystal of Al-Cu-Fe based quasicrystal material is the most famous and common one in the quasicrystal family. It has a regular icosahedral symmetry, and the rotational symmetry of the regular icosahedral quasicrystal includes 5-fold, 3-fold and 2-fold symmetry axes, among which the most significant is the 5-fold symmetry. This 5-fold symmetry cannot be achieved in traditional crystal structures. The regular icosahedral symmetry gives quasicrystals multiple physical properties. Among these physical properties, the pseudo-energy gap of the electronic state density of the quasicrystal will cause the thermal conductivity of the material of the quasicrystal material base layer 1 to be positively correlated with temperature.

[0046] It should be noted that Cu-Ag-Se-based thermoelectric materials are a class of advanced thermoelectric materials with copper (Cu) and silver (Ag) as the metal matrix and selenium (Se) as the chalcogenide framework. Through the synergistic effect of dynamic cation migration and a rigid anion framework, they achieve decoupled optimization of electrical and thermal transport properties. Cu-Ag-Se-based thermoelectric materials exhibit phase transition properties. Specifically, at low temperatures, the crystal structure of Cu-Ag-Se-based thermoelectric materials is a β phase (low-temperature phase) with a pseudo-tetragonal orthorhombic structure, exhibiting a layered stacking characteristic in spatial structure. At this point, the Cu-Ag-Se-based thermoelectric material has a metallic phase. At high temperatures, the β phase of the Cu-Ag-Se-based thermoelectric material undergoes a phase transition, transforming the crystal structure of the Cu-Ag-Se-based thermoelectric material into a cubic α phase. The cubic α phase has low lattice thermal conductivity similar to that of a semiconducting phase, resulting in low thermal conductivity at high temperatures.

[0047] It should be noted that the shape of the quasi-crystalline material matrix layer 1 can be selected from at least one of the following: columnar, cube, and pyramidal; and the shape of the thermoelectric material layer 2 can be selected from at least one of the following: columnar, cube, and pyramidal. Generally, the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 have the same shape.

[0048] It should be noted that the embodiments of the present application provide a quasi-crystal-based solid-state composite thermally conductive material. The principle of the composite thermally conductive material having a good thermal rectification ratio can be further explained from the following multiple dimensions:

[0049] 1. Positive correlation between thermal conductivity of quasi-crystalline material substrate layer 1 and temperature:

[0050] (1) Modulation effect of pseudo-gap on electron thermal transport:

[0051] The 20-dimensional symmetric Al-Cu-Fe based quasi-crystalline material has a pseudo-band gap (pseudo-energy gap) near the Fermi level, and its electronic density of states (DOS) is significantly lower than that of conventional crystals. The formation of this pseudo-band gap is due to:

[0052] 1) Interference effect of quasi-periodic atomic arrangement: The long-range quasi-periodicity of quasicrystals causes destructive interference of electron wave functions, suppressing the electron state density near the Fermi surface and forming a bandgap-like structure.

[0053] 2) Strong electron-phonon coupling: The strong interaction between electrons and localized phonon modes in the quasicrystal further compresses the density of states near the Fermi level and enhances the pseudoband gap effect.

[0054] (2) Temperature-dependent electronic excitation mechanism:

[0055] Increasing the temperature triggers thermally activated transport of electrons across the pseudogap:

[0056] 1) Increase in the concentration of thermally excited carriers: When the temperature rises, electrons gain thermal energy, causing some electrons to be excited to the extended state above the pseudoband gap, and the concentration of carriers participating in heat conduction will increase exponentially.

[0057] 2) Inversion of carrier mobility temperature dependence: In conventional crystals, electron mobility μ usually decreases with increasing temperature T, but in quasicrystals, the presence of a pseudoband gap leads to the following:

[0058] When the quasicrystal is in a low temperature state, the carriers are mainly confined in the pseudo-band gap, and μ is dominated by defect scattering, making μ negatively correlated with T (μ∝T -1 );

[0059] When the quasicrystal is in a high temperature state, the heat will excite the carriers into the extended state, and μ will be dominated by the scattering of acoustic phonons, turning into μ∝T -0.5 Combined with the exponential growth of carrier concentration, the overall electronic thermal conductivity will show an upward trend.

[0060] (3) Macroscopic average effect of quasicrystals:

[0061] 1) Dual effects of grain boundaries on electron transport:

[0062] Under low temperature conditions, the grain boundary scattering of the quasicrystal will dominate the thermal resistance of the quasicrystal, causing the thermal resistance of the quasicrystal to increase, thereby reducing the thermal conductivity of the electrons; while under high temperature conditions, the quasicrystal will excite carriers through heat, causing the energy of the quasicrystal to exceed the height of the grain boundary potential barrier, weakening the scattering effect of the quasicrystal's grain boundaries on extended-state electrons, causing the thermal conductivity of the electrons to rise again.

[0063] 2) Synergistic effect of quasicrystal system:

[0064] The pseudoband gap width distribution of different grains in the quasicrystal will have a synergistic thermal activation effect to broaden the effective temperature response range of the quasicrystal.

[0065] 2. Negative correlation between thermal conductivity and temperature of thermoelectric material layer 2:

[0066] Phase transition-driven structural disorder and enhanced phonon scattering:

[0067] (1) Low-temperature semi-metal phase (T<450K):

[0068] 1) Crystal structure characteristics:

[0069] Cu-Ag-Se based thermoelectric materials have an ordered layered structure (such as orthorhombic phase or tetragonal phase) at low temperature. + and Ag + The ions are arranged periodically in the crystal lattice, forming a highly symmetrical atomic configuration.

[0070] 2) Phonon transport characteristics:

[0071] The long-range ordered structure makes the phonons (lattice vibration quanta) of Cu-Ag-Se based thermoelectric materials have a long mean free path and the thermal conductivity of the lattice is high.

[0072] (2) High temperature semi-conductive phase (T>450K):

[0073] 1) Dynamic disorder phase transition:

[0074] When the temperature exceeds the critical point, the Cu ions and Ag ions in the Cu-Ag-Se based thermoelectric material will undergo a disordered transition in position, and some ions will break away from their originally fixed lattice sites to form a liquid-like disordered structure.

[0075] 2) Phonon scattering mechanism:

[0076] The disorder phase transition leads to the following results:

[0077] Localized phonon mode: high-frequency phonons are localized and cannot participate in heat conduction;

[0078] Mass disorder scattering: The significant mass difference between Cu and Ag will induce strong phonon scattering, causing a sharp drop in the thermal conductivity of the Cu-Ag-Se based thermoelectric material lattice.

[0079] (2) Phase change control of electronic thermal conductivity:

[0080] 1) Electron transport in low-temperature semimetal phase:

[0081] Band structure characteristics: The slight overlap of the conduction band and the valence band in the semi-metal phase of Cu-Ag-Se based thermoelectric materials will form an electron gas with low carrier concentration.

[0082] Contribution of electronic thermal conductivity: Electronic thermal conductivity is approximately equal to the product of the Lorentz number and electrical conductivity. Under low temperature conditions, the electrical conductivity of Cu-Ag-Se based thermoelectric materials is high, which makes the electronic thermal conductivity less than half of the total thermal conductivity of the electrons.

[0083] 2) Transition of electronic behavior of high-temperature semiconducting phase:

[0084] The carrier concentration drops sharply: after the phase transition, the overlapping region of the energy band disappears, and the Cu-Ag-Se based thermoelectric material transforms into a narrow bandgap semiconductor, reducing the carrier concentration;

[0085] Exponential decay of electronic thermal conductivity: After the phase transition of Cu-Ag-Se based thermoelectric materials, the band gap width of Cu-Ag-Se based thermoelectric materials will increase, which will cause the contribution of electronic thermal conductivity to decrease to <5%.

[0086] (3) Cooperative scattering effect near the critical temperature:

[0087] In the phase transition critical region of Cu-Ag-Se based thermoelectric materials, Cu-Ag-Se based thermoelectric materials will show strong coupling between structural fluctuations and electrons and phonons:

[0088] 1) Pre-melting phenomenon:

[0089] Local regions in the lattice become disordered before the overall structure, forming a dynamic "order-disorder" interface and triggering strong interface phonon scattering.

[0090] 2) Enhanced electron-phonon interaction: Electrons undergo inelastic scattering with localized phonons in the fluctuation region, further inhibiting hot carrier transport and causing a sudden drop in the thermal conductivity of the Cu-Ag-Se based thermoelectric material near the phase transition point.

[0091] (3) The negative correlation between the thermal conductivity and temperature of Cu-Ag-Se based thermoelectric materials is mainly due to the multi-scale synergistic effect induced by phase transition: 1) Structural disorder will destroy the long-range ordered Cu-Ag-Se based thermoelectric materials and enhance phonon scattering; 2) Electronic band reconstruction will suppress the carrier concentration and weaken the electronic thermal conductivity; 3) Critical fluctuations will induce strong coupling between electrons and phonons, amplifying the thermal resistance mutation.

[0092] 3. Working principle of asymmetric thermal resistance network:

[0093] The different correlations between quasicrystals and Cu-Ag-Se based thermoelectric materials and temperature construct a direction-sensitive asymmetric thermal resistance network structure of the composite thermal conductive material: in the case of forward heat conduction of the composite thermal conductive material, both the quasicrystals and the Cu-Ag-Se based thermoelectric materials have low thermal resistance, and the overall thermal resistance of the composite thermal conductive material is at a low level, which promotes the thermal conduction of the composite thermal conductive material; in the case of reverse heat conduction of the composite thermal conductive material, both the quasicrystals and the Cu-Ag-Se based thermoelectric materials have high thermal resistance, which makes the overall thermal resistance of the composite thermal conductive material at a high level, hindering the thermal conduction of the composite thermal conductive material; this low thermal resistance in forward heat conduction and high thermal resistance in reverse heat conduction will form an asymmetric thermal resistance network structure, which can control the thermal conduction direction of the composite thermal conductive material and reduce the ineffective heat conduction process.

[0094] 4. Nonlinear response driven by temperature gradient:

[0095] The improvement of thermal rectification ratio depends on the nonlinear effect of temperature gradient:

[0096] (1) Temperature dependence of thermal conductivity of quasicrystals:

[0097] The thermal conductivity of quasicrystals exhibits a non-monotonic change with increasing temperature (e.g., phonons dominate at low temperatures, electrons dominate at high temperatures). Within a specific temperature range, the difference in thermal conductivity between forward and reverse heat transfer is amplified.

[0098] (2) Self-consistent field effect of Cu-Ag-Se based thermoelectric materials:

[0099] Temperature gradients trigger the Seebeck potential (V) of Cu-Ag-Se-based thermoelectric materials, which in turn modulates the carrier concentration distribution within the material, forming a positive feedback loop. In the case of forward heat conduction, V enhances carrier transport efficiency; in the case of reverse heat conduction, V inhibits carrier movement, exacerbating the difference in thermal resistance between composite thermal conductive materials under different heat conduction conditions.

[0100] 5. Optimization of multi-scale energy transfer paths:

[0101] Multi-scale design strategies from micro to macro:

[0102] (1) Nanoscale phonon engineering

[0103] The phonon group velocity is directionally modulated by designing quasicrystal types (e.g., quasi-periodic superlattices) to maximize the thermal conductivity ratio of forward heat conduction and the thermal conductivity ratio of reverse heat conduction.

[0104] (2) Mesoscopic thermal circuit design:

[0105] The geometric parameters of composite thermal conductive materials (such as thickness ratio and cross-sectional shape) can optimize heat flow distribution and avoid efficiency loss caused by local heat accumulation.

[0106] (3) Macroscopic thermodynamic matching:

[0107] The matching design of thermal expansion coefficient and interface stress of Al-Cu-Fe based quasi-crystalline materials and Cu-Ag-Se based thermoelectric materials can ensure the structural stability under high temperature operation and maintain the long-term thermal rectification performance of solid-state composite thermal diodes.

[0108] In summary, the embodiment of the present application provides a quasi-crystal-based solid-state composite thermal conductive material, which includes a quasi-crystal material matrix layer 1 and a thermoelectric material layer 2. Due to the characteristics that the thermal conductivity of the quasi-crystal material matrix layer 1 is positively correlated with the temperature and the thermal conductivity of the thermoelectric material layer 2 is negatively correlated with the temperature, an asymmetric thermal resistance network structure is provided between the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2. In the case of heat conduction, this asymmetric thermal resistance network structure can enhance the forward heat conduction effect and hinder the reverse heat conduction effect, thereby improving the rectification ratio of the thermal composite thermal conductive material. The core innovation of this composite thermal conductive material lies in the deep fusion of the intrinsic properties of two different materials (the relationship between temperature and thermal conductivity) to form a dynamic and adaptive heat flow control system.

[0109] It should be noted that the thermal rectification ratio (TRR) is an important parameter to measure the thermal control performance of thermal conductive materials. The calculation formula of TRR is TRR = J for / J rev , J for is the heat of forward heat conduction, J rev The heat conducted in the reverse direction is called the TRR. Therefore, the higher the TRR value, the greater the difference between the forward and reverse heat conduction processes of the thermal conductive material. In other words, the rectification effect of the thermal conductive material is significant, which means that the thermal conductive material has a good thermal rectification ratio.

[0110] In some optional embodiments, the number of Al, Cu and Fe atoms in the Al-Cu-Fe based quasi-crystalline material satisfies: 61<[Al]<64, 23<[Cu]<27, 11<[Fe]<13, wherein [Al] is the number of Al atoms, [Cu] is the number of Cu atoms, and [Fe] is the number of Fe atoms.

[0111] In these embodiments, the Al-Cu-Fe-based quasi-crystalline material is a material having Al (atomic number 61 < [Al] < 64) as a matrix, with Cu (atomic number 23 < [Cu] < 27) and Fe (11 < [Fe] < 13) as doping elements. The incorporation of Cu and Fe can manipulate the structure and properties of the quasi-crystalline, resulting in the Al-Cu-Fe-based quasi-crystalline material exhibiting icosahedral symmetry.

[0112] It should be noted that the number of Al atoms may be 61.5, 62.0, or 63.2; the number of Cu atoms may be 23.8, 24.2, 25.5, or 26.5; and the number of Fe atoms may be 11.3, 12.0, or 12.5.

[0113] In some optional embodiments, the Al-Cu-Fe based quasi-crystalline material is selected from the following: Al 61.5 Cu 26.5 Fe 12 、Al 62 Cu 25.5 Fe 12.5 、Al 63.2 Cu 24.2 Pt 0.9 Fe 11.3 and Al 63.2 Cu 23.8 Pt 1.7 Fe 11.3 .

[0114] In these embodiments, the polyhedral Al, Cu, and Fe system of the Al-Cu-Fe based quasi-crystalline material has a regular icosahedral symmetry.

[0115] In some optional embodiments, the number of Cu, Ag and Se atoms in the Cu-Ag-Se based thermoelectric material is 1.

[0116] In these embodiments, when the temperature exceeds the critical point, the Cu ions and Ag ions of the Cu-Ag-Se based thermoelectric material will undergo a positional disorder transformation, and some ions will break away from their originally fixed lattice sites to form a liquid-like disordered structure. The liquid-like disordered structure can reduce the thermal conductivity of the lattice of the Cu-Ag-Se based thermoelectric material, causing the thermoelectric material layer 2 to have a characteristic of negative correlation between thermal conductivity and temperature. The thermoelectric material layer 2 can further hinder the reverse heat transfer of the composite thermal conductive material, thereby effectively improving the thermal rectification ratio of the composite thermal conductive material.

[0117] In some optional embodiments, the Cu-Ag-Se based thermoelectric material is selected from the following: CuAgSe, Ni 0.02 CuAgSe and Zn 0.02 CuAgSe.

[0118] In these embodiments, under high temperature conditions, CuAgSe, Ni 0.02 CuAgSe and Zn 0.02 The β phase of CuAgSe, a copper-silver-selenium (Cu-Ag-Se)-based thermoelectric material, undergoes a phase transition to the cubic α phase. The cubic α phase has lower lattice thermal conductivity, resulting in lower thermal conductivity at high temperatures. Furthermore, the high mobility of copper ions exhibits liquid ion behavior, further reducing the low lattice thermal conductivity of the cubic α phase.

[0119] In some optional embodiments, the thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: 10mm≤L1+L2≤200mm, and L1:L2=x:(1-x), where x is 0.6~0.8.

[0120] In these embodiments, the thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: 10mm≤L1+L2≤200mm, so that the composite thermal conductive material has a sufficiently thick heat conduction path to improve the thermal conductivity of the composite thermal conductive material. In addition, the value of x can be 0.6 to 0.8, so that the quasi-crystalline material matrix layer 1 occupies most of the area of the composite thermal conductive material, thereby increasing the length of the forward low thermal resistance path of the composite thermal conductive material and improving the forward heat transfer effect of the composite thermal conductive material. In addition, the value of x can also regulate the thickness of the thermal conduction path of the thermoelectric material layer 2 to optimize the performance distribution of the Cu-Ag-Se based thermoelectric material, thereby effectively improving the thermal rectification ratio of the composite thermal conductive material.

[0121] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm or 200mm.

[0122] The value of x can be 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.70, 0.75 or 0.80.

[0123] It should be noted that x refers to the ratio of the thickness of the corresponding quasi-crystalline material matrix 1 to the thickness of the entire composite thermal conductive material under the conditions that the high-temperature end temperature of the composite thermal conductive material is 600K and the low-temperature end temperature is 300K.

[0124] In some optional embodiments, the projection areas of the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 in the thickness direction are 78 mm and 10 mm, respectively. 2 ~7854mm 2 .

[0125] In these embodiments, the projection areas of the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 in the thickness direction can be 78 mm and 10 mm, respectively. 2 ~7854mm 2 , so that a sufficiently large area of asymmetric thermal resistance network structure is formed between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2. The large area of the asymmetric thermal resistance network structure can greatly improve the difference between the forward heat conduction and the reverse heat conduction of the composite thermal conductive material, thereby improving the thermal rectification ratio of the composite thermal conductive material.

[0126] The projected areas of the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2 in the thickness direction can be 78 mm 2 , 80mm 2 , 82mm 2 , 84mm 2 , 86mm 2 , 88mm 2 , 90mm 2 , 100mm 2 , 200mm 2 , 300mm 2 , 400mm 2 , 500mm 2 , 1000mm 2 , 2000mm 2 , 3000mm 2 , 4000mm2 , 5000mm 2 , 6000mm 2 , 7000mm 2 , 7500mm 2 , 7800mm 2 or 7854mm 2 .

[0127] In some optional embodiments, the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 have the same projected area in the thickness direction.

[0128] In these embodiments, the projected areas of the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 in the thickness direction can be the same, so that a sufficiently stable asymmetric thermal resistance network structure is formed between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2; in addition, the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 with the same projected areas can avoid the occurrence of thermal radiation conduction, so as to maximize the difference between the forward thermal conduction effect and the reverse thermal conduction effect of the composite thermal conductive material, thereby improving the thermal rectification ratio of the composite thermal conductive material.

[0129] Figure 2 The following is a schematic structural diagram of a quasi-crystal-based solid composite thermally conductive material containing a thermally conductive coating 5 provided in an embodiment of the present application;

[0130] In some optional embodiments, such as Figure 2 As shown, the composite thermally conductive material further includes a thermally conductive coating layer 5 , which is disposed between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 .

[0131] In these embodiments, the composite thermally conductive material may further include a thermally conductive coating 5, and the thermally conductive coating 5 is covered between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2. The thermally conductive coating 5 can reduce the interface thermal resistance between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2. The composite thermally conductive material with low interface thermal resistance has a good positive heat conduction effect.

[0132] It should be noted that the raw material used for the thermal conductive coating 5 can be thermal conductive paste, metal adhesive, or a mixture of thermal conductive paste and metal adhesive. The metal adhesive can be silver adhesive.

[0133] Figure 4 A schematic flow chart of a method for preparing the composite thermal conductive material is shown as an example;

[0134] Based on a general inventive concept, such as Figure 4 As shown, the embodiment of the present application provides a method for preparing the composite thermal conductive material, comprising:

[0135] S1. The metal powder of the quasi-crystalline material containing Al, Cu and Fe is sequentially pressed, arc-melted, first sintered and polished to obtain a quasi-crystalline material matrix layer 1 having a flat interface;

[0136] S2. The metal powder of the Cu-Ag-Se based thermoelectric material is sequentially pressed, arc melted, sintered and polished to obtain a thermoelectric material layer 2 having a flat interface;

[0137] S3. The quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 are butted together at a flat interface to obtain a solid composite thermal conductive material.

[0138] This method is a method for preparing the above-mentioned composite thermally conductive material. The specific composition of the composite thermally conductive material can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0139] It should be noted that before the first sintering or the second sintering, the bulk alloy of the Al-Cu-Fe based quasi-crystalline material or the Cu-Ag-Se based thermoelectric material obtained by arc melting can be crushed into fine powder by pulverizing. These fine powders can be fully mixed with each other through the first sintering or the second sintering treatment to form a dense quasi-crystalline material matrix layer 1 or thermoelectric material layer 2.

[0140] It should be noted that the polishing process can form a smooth interface on the surface of the quasi-crystalline material matrix layer 1 or the thermoelectric material layer 2. These smooth interfaces can facilitate the stability of the subsequent connection between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2.

[0141] It should be noted that there are many ways to dock the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2. For example, the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 can be physically docked by extrusion, or they can be chemically docked by using an adhesive for chemical bonding.

[0142] It should be noted that the metal powder of the Al-Cu-Fe based quasi-crystal material can be high purity (≥99.99%) Al, Cu and Fe, or high purity (≥99.99%) Al, Cu, Fe and Pt.

[0143] It should be noted that the metal powder of the Cu-Ag-Se based thermoelectric material can be high-purity (≥99.99%) Cu, Ag and Se, or high-purity (≥99.99%) Cu, Ag, Se and Ni, or high-purity (≥99.99%) Cu, Ag, Se and Zn.

[0144] It should be noted that the polishing process can be divided into a sandpaper polishing section and a polishing paste polishing section. In the sandpaper polishing section, the particle size of the sandpaper can be gradually reduced, for example, the sandpaper can be gradually increased from 120 mesh to 2000 mesh; the polishing paste polishing section uses polishing paste for uniform polishing.

[0145] It should be noted that during the arc melting process, the arc furnace must first be vacuumed to ensure a pure environment and keep the oxygen content below the ppm level. High-purity argon is then injected into the furnace to prevent oxidation of the metal powders of the Al-Cu-Fe-based quasi-crystalline material and the Cu-Ag-Se-based thermoelectric material within the furnace with oxygen, thereby improving the purity of the composite thermal conductive material.

[0146] In some optional embodiments, the first sintering temperature T01 satisfies: T11-T01=180°C to 220°C, where T11 represents the melting point of the metal element with the lowest melting point in the Al-Cu-Fe based quasi-crystalline material; or

[0147] The second sintering temperature T02 satisfies: T12-T02=180°C to 220°C, where T12 represents the melting point of the metal element with the lowest melting point in the Cu-Ag-Se based thermoelectric material.

[0148] In these embodiments, the temperature T01 of the first sintering satisfies: T11-T01=180℃~220℃, where T11 represents the melting point of the metal element with the lowest melting point in the Al-Cu-Fe based quasi-crystalline material, or the temperature T02 of the second sintering satisfies: T12-T02=180℃~220℃, where T12 represents the melting point of the metal element with the lowest melting point in the Cu-Ag-Se based thermoelectric material. Under these sintering temperature conditions, the metal powder of the Al-Cu-Fe based quasi-crystalline material or the Cu-Ag-Se based thermoelectric material can be prevented from melting during the first sintering or the second sintering process; in addition, the first sintering or the second sintering can form a dense structure between different metal powders, thereby obtaining a dense quasi-crystalline material matrix layer 1 and a thermoelectric material layer 2.

[0149] The first sintering temperature T01 satisfies: T11-T01=180°C, 190°C, 200°C, 210°C or 220°C.

[0150] The second sintering temperature T02 satisfies: T12-T02=180°C, 190°C, 200°C, 210°C or 220°C.

[0151] It should be noted that the time for the first sintering and the second sintering can be 15 minutes to 20 minutes respectively. Sufficient time for the first sintering or the second sintering allows a dense structure to be formed between the metal powders of the Al-Cu-Fe based quasi-crystalline material or the metal powders of the Cu-Ag-Se based thermoelectric material, and a dense quasi-crystalline material matrix layer 1 and a thermoelectric material layer 2 can be obtained.

[0152] Figure 3 The following is a schematic structural diagram of a quasi-crystal-based solid-state composite thermal diode provided in an embodiment of the present application;

[0153] Based on a general inventive concept, such as Figure 3 As shown, an embodiment of the present application provides a quasi-crystal-based solid-state composite thermal diode, comprising a heat conductor 3 and the columnar composite thermal conductive material.

[0154] The solid-state composite thermal diode is realized based on the above-mentioned composite thermal conductive material. The specific composition of the composite thermal conductive material can refer to the above-mentioned embodiment. Since the solid-state composite thermal diode adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0155] It should be noted that in order to make the solid-state composite thermal diode work normally, the quasi-crystalline material matrix layer 1 is generally arranged upstream of the thermoelectric material layer 2 along the positive direction of heat conduction to improve the difference between the forward heat conduction effect and the reverse heat conduction effect of the solid-state composite thermal diode, thereby improving the thermal rectification ratio of the composite thermal conductive material.

[0156] It should be noted that the positive direction of heat conduction refers to the direction in which heat is transferred spontaneously from a high-temperature area to a low-temperature area. This heat conduction process does not require external forces and is determined by the temperature gradient.

[0157] It should be noted that the diameter of the columnar quasi-crystalline material matrix layer 1 can be the same as the diameter of the columnar thermoelectric material layer 2 to avoid misalignment in the docking between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2, so that the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 can form a composite thermal conductive material with an asymmetric thermal resistance network effect, thereby effectively improving the thermal rectification ratio of the solid-state composite thermal diode.

[0158] It should be noted that the material of the heat conductor 3 can be copper.

[0159] It should be noted that this solid-state composite thermal diode can be used as a component of a heat conduction device. A heat conduction device constructed using this solid-state composite thermal diode can be used in an on-board cooling system. This on-board cooling system can be used for heat dissipation in air conditioning systems of new energy vehicles, or it can be used to cool the battery modules of new energy vehicles.

[0160] In some optional embodiments, the solid-state composite thermal diode further includes a radiation shielding layer 4 , which is disposed around the outer periphery of the composite thermal conductive material.

[0161] In these embodiments, the solid-state composite thermal diode may further include a radiation shielding layer 4, and the radiation shielding layer 4 is disposed around the outer periphery of the composite thermal conductive material. Based on the radiation shielding layer 4, the following synergistic optimization effects may be achieved:

[0162] 1. Thermal radiation suppression:

[0163] High reflectivity reduces radiation heat loss: The metal material used in the radiation shielding layer 4 has a high reflectivity in the infrared band, which can effectively block the outward heat radiation from the surface of the quasi-crystal material base layer 1 and the thermoelectric material layer 2, reduce the heat energy loss caused by blackbody radiation, and improve the heat flow transfer efficiency of the solid-state composite thermal diode.

[0164] 2. Encapsulation protection:

[0165] Prevent oxidation and chemical corrosion: The metal material used in the radiation shielding layer 4 can form a dense oxide film in the air. The existence of this oxide film can isolate the internal material from the erosion of external environments such as oxygen and water vapor, thereby improving the long-term stability of the solid-state composite thermal diode in high temperature or high humidity environments.

[0166] 3. Improved mechanical strength and process compatibility:

[0167] (1) Reducing thermal stress deformation: The thermal expansion coefficient of the metal material used in the radiation shielding layer 4 is between the thermal expansion coefficients of the Al-Cu-Fe based quasi-crystalline material and some Cu-Ag-Se based thermoelectric materials. Therefore, the radiation shielding layer 4 can serve as a stress buffer layer to inhibit the interface cracking between the quasi-crystalline material base layer 1 and the thermoelectric material layer 2 caused by temperature cycling.

[0168] (2) Compatible with semiconductor packaging process: The radiation shielding layer 4 can be directly deposited by magnetron sputtering or electron beam evaporation, and can be seamlessly integrated with existing chip-level packaging technology (such as flip-chip bonding), reducing manufacturing costs.

[0169] 4. Synergistic mechanism:

[0170] The radiation shielding layer 4 achieves performance improvement through the dual physical field coupling of heat and force: thermal radiation suppression reduces energy dissipation → mechanical protection extends service life, forms a forward enhancement closed loop, and improves the thermal rectification ratio of the solid-state composite thermal diode.

[0171] It should be noted that the radiation shielding layer 4 can be made of aluminum. Based on the characteristics of aluminum having a reflectivity of more than 90% and a low emissivity of about 4%, the radiation shielding layer 4 can significantly reduce the thermal radiation loss of the solid-state composite thermal diode.

[0172] In some optional embodiments, the distance between the inner surface of the radiation shielding layer 4 and the outer surface of the composite thermally conductive material is less than or equal to the radius of the composite thermally conductive material; and / or,

[0173] The thickness of the radiation shielding layer is 1 mm to 1.5 mm.

[0174] In these embodiments, the distance between the inner surface of the radiation shielding layer 4 and the outer surface of the composite thermal conductive material can be less than or equal to the radius of the composite thermal conductive material, so that the radiation shielding layer 4 can form a sufficiently large protective interface on the surface of the composite thermal conductive material to ensure the heat conduction process of the composite thermal conductive material and avoid the influence of the external environment on the composite thermal conductive material; in addition, the thickness of the radiation shielding layer 4 can be 1 mm to 1.5 mm, so that the radiation shielding layer 4 has sufficient thickness to improve the protection capability of the radiation shielding layer 4.

[0175] The thickness of the radiation shielding layer 4 may be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm.

[0176] Figure 5 A schematic flow chart of a method for preparing a solid-state composite thermal diode provided in an embodiment of the present application is exemplarily shown;

[0177] Based on a general inventive concept, such as Figure 5 As shown, the embodiment of the present application provides a method for preparing the solid-state composite thermal diode, the method comprising:

[0178] S1. Obtaining the columnar composite thermally conductive material;

[0179] S2. The two heat conductors 3 are connected to the two opposite heat conducting ends of the composite thermally conductive material to obtain a composite thermal diode core;

[0180] S3. Disposing a radiation shielding layer 4 around the outer periphery of the composite thermal diode core to obtain a solid composite thermal diode.

[0181] This method is a method for preparing the above-mentioned solid-state composite thermal diode. The specific structure of the solid-state composite thermal diode can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0182] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0183] Example 1

[0184] like Figure 1 As shown, a quasi-crystal-based solid-state composite thermal conductive material has a two-layer structure, including: a quasi-crystal material matrix layer 1 and a thermoelectric material layer 2; wherein, the material of the quasi-crystal material matrix layer 1 is an Al-Cu-Fe based quasi-crystal material, and the material of the thermoelectric material layer 2 is a Cu-Ag-Se based thermoelectric material; the thermal conductivity of the material of the quasi-crystal material matrix layer 1 is positively correlated with temperature, and the thermal conductivity of the material of the thermoelectric material layer 2 is negatively correlated with temperature.

[0185] Al-Cu-Fe based quasi-crystalline materials are Al 61.5 Cu 26.5 Fe 12 .

[0186] The Cu-Ag-Se based thermoelectric material is CuAgSe.

[0187] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.70.

[0188] The projection areas of the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 in the thickness direction are the same.

[0189] like Figure 2 As shown, the composite thermally conductive material further includes a thermally conductive coating layer 5, which is provided between the quasi-crystalline material base layer 1 and the thermoelectric material layer 2. The raw material of the thermally conductive coating layer 5 is thermal conductive paste.

[0190] like Figure 4 As shown, a method for preparing a composite thermal conductive material comprises:

[0191] S1. The metal powder of the Al-Cu-Fe based quasi-crystalline material is sequentially pressed, arc-melted, first sintered and polished to obtain a quasi-crystalline material matrix layer 1 having a flat interface;

[0192] S2. The Cu-Ag-Se based thermoelectric material metal powder is sequentially pressed, arc melted, sintered and polished to obtain a thermoelectric material layer 2 having a flat interface;

[0193] S3. The quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 are butted together at a flat interface to obtain a solid composite thermal conductive material.

[0194] The temperature T01 of the first sintering satisfies: T11-T01=200°C, where T11 represents the melting point of the metal element with the lowest melting point in the Al-Cu-Fe based quasi-crystalline material;

[0195] The temperature T02 of the second sintering satisfies: T12-T02=200°C, where T12 represents the melting point of the metal element with the lowest melting point in the Cu-Ag-Se based thermoelectric material.

[0196] The time for the first sintering and the second sintering was 15 min.

[0197] like Figure 3 As shown, a quasi-crystal-based solid-state composite thermal diode includes a thermal conductor 3 and a columnar composite thermal conductive material.

[0198] The diameter of the heat conductor 3 is 15 mm, and the thickness of the heat conduction path of the heat conductor 3 is 5 mm.

[0199] The diameters of the columnar quasi-crystalline material matrix layer 1 and the columnar thermoelectric material layer 2 are the same, both 10 mm. At this time, the contact surface area between the quasi-crystalline material matrix layer 11 and the thermoelectric material layer 2 is 78 mm. 2 .

[0200] The solid-state composite thermal diode further comprises a radiation shielding layer 4 , which is arranged around the outer periphery of the composite thermal conductive material.

[0201] The thickness of the radiation shielding layer 4 is 1 mm, and the diameter of the radiation shielding layer 4 is 20 mm.

[0202] like Figure 5 As shown, a method for preparing a solid-state composite thermal diode comprises:

[0203] S1. Obtaining a columnar composite thermally conductive material;

[0204] S2. The two heat conductors 3 are connected to the two opposite ends of the composite thermally conductive material to obtain a composite thermal diode core;

[0205] S3. Arrange the radiation shielding layer 4 around the outer periphery of the composite thermal diode core to obtain a solid composite thermal diode.

[0206] Example 2

[0207] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0208] Al-Cu-Fe based quasi-crystalline materials are Al 62 Cu 25.5 Fe 12.5 .

[0209] Example 3

[0210] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0211] Al-Cu-Fe based quasi-crystalline materials are Al 63.2 Cu 24.2 Pt 0.9 Fe 11.3 .

[0212] Example 4

[0213] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0214] Al-Cu-Fe based quasi-crystalline materials are Al 63.2 Cu 23.8 Pt 1.7 Fe 11.3 .

[0215] Example 5

[0216] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0217] Cu-Ag-Se based thermoelectric materials are Ni 0.02 CuAgSe.

[0218] Example 6

[0219] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0220] Cu-Ag-Se based thermoelectric materials are Zn 0.02 CuAgSe.

[0221] Example 7

[0222] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0223] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.6.

[0224] Example 8

[0225] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0226] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.8.

[0227] Example 9

[0228] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0229] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=200 mm, and L1:L2=x:(1-x), where x is 0.7.

[0230] Example 10

[0231] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0232] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=100 mm, and L1:L2=x:(1-x), where x is 0.7.

[0233] Comparative Example 1

[0234] Compared with Example 1, the differences of this comparative example are as follows, and the rest of the technical solutions are the same:

[0235] Al-Cu-Fe based quasi-crystalline material Al 61.5 Cu 26.5 Fe 12 Replaced by Ag2Se.

[0236] Comparative Example 2

[0237] Compared with Example 1, the differences of this comparative example are as follows, and the rest of the technical solutions are the same:

[0238] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.1.

[0239] Comparative Example 3

[0240] Compared with Example 1, the differences of this comparative example are as follows, and the rest of the technical solutions are the same:

[0241] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.2.

[0242] Comparative Example 4

[0243] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0244] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.3.

[0245] Comparative Example 5

[0246] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0247] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.4.

[0248] Comparative Example 6

[0249] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0250] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.5.

[0251] Comparative Example 7

[0252] Compared with Example 1, this embodiment has the following differences, and the rest of the technical solutions are the same:

[0253] The thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2 satisfy the relationship: L1+L2=20 mm, and L1:L2=x:(1-x), where x is 0.9.

[0254] Comparative Example 8

[0255] Compared with Example 1, the differences of this comparative example are as follows, and the rest of the technical solutions are the same:

[0256] The radiation shield 4 is not used.

[0257] Related experiments and effect data:

[0258] 1. The calculation process of thermal rectification ratio (TRR) is as follows:

[0259] According to Figure 6 The heat conduction direction of the solid composite thermal diode shown is the positive direction, and its forward heat flow J for It can be expressed as: Where, L = L1 + L2; T α is the heat of the contact surface between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 under the condition of forward heat transfer; κ A (T) is the temperature dependence function of the thermal conductivity of the quasi-crystalline material matrix layer 1; κ B (T) is the temperature dependence function of the thermal conductivity of the thermoelectric material layer 2; T H is the high temperature end temperature of the composite thermal conductive material, T L is the low temperature end temperature of the composite thermal conductive material.

[0260] The reverse heat can be expressed as: Where, L = L1 + L2; T β is the heat of the contact surface between the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 under reverse heat transfer; κ A (T) is the temperature dependence function of the thermal conductivity of the quasi-crystalline material matrix layer 1; κ B (T) is a function of the dependence of the thermal conductivity of the thermoelectric material layer 2 on temperature.

[0261] Based on the above heat formula, combined with the relationship between the thickness L1 of the quasi-crystalline material matrix layer 1 and the thickness L2 of the thermoelectric material layer 2: L1:L2=x:(1-x), x and T can be determined. α and T β The specific relationship is as follows: as well as

[0262] Based on the above formula, when the high-temperature end temperature and the low-temperature end temperature of the solid-state composite thermal diode are given, combined with the thermal conductivity and temperature dependence function of the Al-Cu-Fe based quasicrystal material of the quasicrystal material matrix layer 1 and the thermal conductivity and temperature dependence function of the Cu-Ag-Se based thermoelectric material of the thermoelectric material layer 2, the forward heat and reverse heat of the composite thermal conductive material can be directly calculated, and the whole heat flow ratio of the composite thermal conductive material can be calculated through the forward heat and reverse heat.

[0263] The solid composite thermal diodes obtained in Examples 1 to 10 and Comparative Examples 1 to 7 were respectively subjected to the temperature conditions of a high-temperature end temperature of 700K and a low-temperature end temperature of 300K (700K, 300K), and the maximum total heat flux ratio TRR of the solid composite thermal diode was calculated according to the above formula. max , the results are shown in Table 1.

[0264] Table 1 Maximum total heat flux ratio TRR of solid composite thermal diodes of Examples 1 to 10 and Comparative Examples 1 to 8 max result

[0265]

[0266] As shown in Table 1, from Examples 1 to 6 and Comparative Example 1, it can be seen that when using traditional crystal materials as the matrix layer instead of Al-Cu-Fe-based quasi-crystalline materials, the solid-state composite thermal diodes prepared have a low thermal rectification ratio at a high-temperature end temperature of 700K. From Examples 1, 7, 8, and Comparative Examples 2 to 7, it can be seen that the ratio between the thickness of the quasi-crystalline material matrix layer 1 and the thickness of the thermoelectric material layer 2 has a significant impact on the thermal rectification ratio of the solid-state composite thermal diode. In addition, from Examples 1, 9, and 10, it can be seen that when the total thickness of the composite thermal conductive material (L1+L2) satisfies 10mm≤L1+L2≤200mm, the thermal conductivity of the solid-state composite thermal diode is relatively excellent.

[0267] 2. Based on the formula provided in Experiment 1, the powder remaining on the contact surface of the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2 in Example 1 during the polishing process was subjected to X-ray diffraction treatment. The results are as follows: Figure 6 (a) As shown; In addition, for the Al-Cu-Fe based quasi-crystalline material used in the quasi-crystalline material matrix layer 1 and the Cu-Ag-Se based thermoelectric material used in the thermoelectric material layer 2 in Example 1, the dependence function of their thermal conductivity on temperature was statistically analyzed, and the results are shown as follows: Figure 6 (b) As shown; In addition, Example 1 is compared with Comparative Examples 3 to 7, and the changes in the ratio of the thickness of the quasi-crystalline material matrix layer 1 to the thickness of the thermoelectric material layer 2 are statistically analyzed to see the effect on the thermal rectification ratio of the solid-state composite thermal diode in different heat conduction scenarios. The results are shown in FIG. Figure 6 (c) is shown. Figure 6 It can be seen that the material purity of the quasi-crystalline material matrix layer 1 and the thermoelectric material layer 2 of Example 1 is relatively high, and under the temperature conditions of the high temperature end temperature of 600K and the low temperature end temperature of 300K (600K, 300K) and the high temperature end temperature of 700K and the low temperature end temperature of 300K (700K, 300K), the thermal rectification ratio of the solid-state composite thermal diode under the condition of (700K, 300K) is the highest.

[0268] 3. Based on the formula provided in Experiment 1, the solid-state composite thermal diodes of Example 1 and Comparative Examples 3 to 7 were subjected to rectification simulation experiments. The specific process is as follows:

[0269] The forward heat, reverse heat and heat rectification ratio of Example 1 and Comparative Examples 3 to 7 were counted respectively. The results are as follows: Figure 7As shown by Figure 7 (a) It can be seen that the heat distribution of the solid composite thermal diode of Example 1 is relatively uniform. Figure 7 (b) and Figure 7 (c) It can be seen that when x is 0.7, the thermal rectification ratio is the largest and exceeds 3.1. This shows that the solid-state composite thermal diode provided by the embodiment of the present application has excellent thermal conductivity.

[0270] 4. Based on the formula provided in Experiment 1, when the heat conduction direction is determined, the interface thermal resistance of the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2 in Example 1 is calculated. The results show that the interface thermal resistance R t ≤10 -3 Km 2 W -1 In the case of the solid-state composite thermal diode, the thermal rectification ratio changes slightly; while the interface thermal resistance R t =10 -2 Km 2 W -1 Under the condition of , the forward heat flow and reverse heat flow of the solid composite thermal diode change significantly, which makes the thermal rectification ratio of the solid composite thermal diode drop significantly. Therefore, a thermal conductive coating 5 can be provided between the quasi-crystalline material base layer 1 and the thermoelectric material layer 2. The high thermal conductivity of the thermal conductive coating 5 can greatly reduce the interface thermal resistance of the contact surface between the two, so that R t As low as 10 -4 Km 2 W -1 Next, the interface thermal resistance is prevented from affecting the heat conduction effect of the solid-state composite thermal diode.

[0271] 5. Simulation analysis of the radiation effect of the solid composite thermal diode of Example 1. Considering the forward transfer stage of the heat radiation of the solid composite thermal diode, the heat is transferred from the heat conductor 3 (T H =700K) flows into the quasi-crystalline material matrix layer 1, and the heat flow obtained is Q in = 6.35W; and the heat flow from the thermoelectric material layer 2 to the heat conductor 3 of the low-temperature copper cylinder (TL = 300K) is Q out =5.66W, the specific data are shown in Table 2. Then the net radiation heat flow on the side of the diode is calculated to be Q rad =Q in -Q out = 0.69W, it is clear that the radiation loss of the solid-state composite thermal diode is Q rad / Q in =10.8%. Under non-radiation conditions, the forward heat flow Q for and reverse heat flow Q revWhen x is 0.7, the results obtained according to the above calculation process are 5.80 W and 1.82 W. The heat flow values obtained in the different structures of Example 1 and Comparative Example 8 are shown in Table 2.

[0272] Table 2 Heat flow values of Example 1 and Comparative Example 8

[0273]

[0274] As can be seen from Table 2, the radiation shielding layer 4 prepared by introducing aluminum material into the solid-state composite thermal diode can significantly reduce the thermal radiation loss of the solid-state composite thermal diode, so that the thermal radiation loss is reduced from 10.8% to 5.66% when the heat flow is transferred in the forward direction, and the thermal radiation loss is reduced from 14.0% to 3.94% when the heat flow is transferred in the reverse direction. This shows that the solid-state composite thermal diode has good thermal conductivity.

[0275] In summary, the embodiments of the present application provide a quasi-crystal-based solid-state composite thermal conductive material, which includes a quasi-crystal material matrix layer 1 and a thermoelectric material layer 2. Due to the characteristics that the thermal conductivity of the quasi-crystal material matrix layer 1 is positively correlated with temperature and the thermal conductivity of the thermoelectric material layer 2 is negatively correlated with temperature, an asymmetric thermal resistance network structure is provided between the quasi-crystal material matrix layer 1 and the thermoelectric material layer 2. In the case of heat conduction, this asymmetric thermal resistance network structure can enhance the forward heat conduction effect and hinder the reverse heat conduction effect, thereby improving the rectification ratio of the thermal composite thermal conductive material and improving the thermal rectification ratio of the solid-state composite thermal diode. In addition, the radiation shielding layer 4 can almost eliminate thermal radiation loss.

[0276] In addition, the embodiments of the present application provide a quasi-crystal-based solid-state composite thermal diode, which has the following advantages:

[0277] (1) High reliability: Since the solid-state composite thermal diode is designed with pure solid-state composite thermal conductive materials, it does not contain any complex mechanical parts and does not have wear problems, thus making it have a long service life;

[0278] (2) Simple structure: The structure of the solid-state composite thermal diode is relatively simple, mainly consisting of four parts: a quasi-crystalline material base layer 1, a thermoelectric material layer 2, a thermal conductor 3, and a radiation shielding layer 4. The design and manufacturing cost of the overall solid-state composite thermal diode is low, and it is easy to mass-produce;

[0279] (3) Lightweight and miniaturization: The solid-state composite thermal diode is generally a millimeter-sized product, suitable for thermal management in compact spaces, such as the thermal control system inside the battery module of new energy vehicles;

[0280] (4) High efficiency: The solid-state composite thermal diode uses an optimized quasi-crystal material matrix layer 1 and a thermoelectric material layer 2, which can achieve efficient unidirectional heat flow control and improve the energy efficiency of the solid-state composite thermal diode. Therefore, the solid-state composite thermal diode has broad application prospects in thermal management.

[0281] The foregoing is merely a detailed description of the present invention, intended to enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A quasi-crystal-based solid-state composite thermally conductive material, the composite thermally conductive material having at least a two-layer structure, comprising: A quasi-crystalline material matrix layer and a thermoelectric material layer; wherein, the material of the quasi-crystalline material matrix layer is an Al-Cu-Fe based quasi-crystalline material, the quasi-crystalline material has a regular icosahedral symmetry, and the material of the thermoelectric material layer is a Cu-Ag-Se based thermoelectric material; under the condition of heat conduction, an asymmetric thermal resistance network structure is present between the quasi-crystalline material matrix layer and the thermoelectric material layer.

2. The composite thermal conductive material according to claim 1, characterized in that: The number of Al, Cu and Fe atoms in the Al-Cu-Fe based quasi-crystalline material satisfies the following conditions: 61<[Al]<64, 23<[Cu]<27, 11<[Fe]<13, wherein [Al] is the number of Al atoms, [Cu] is the number of Cu atoms, and [Fe] is the number of Fe atoms.

3. The composite thermal conductive material according to claim 2, characterized in that: The Al-Cu-Fe based quasi-crystalline material is selected from the following: Al 61.5 Cu 26.5 Fe 12 、Al 62 Cu 25.5 Fe 12.5 、Al 63.2 Cu 24.2 Pt 0.9 Fe 11.3 and Al 63.2 Cu 23.8 Pt 1.7 Fe 11.3 .

4. The composite thermal conductive material according to claim 1, characterized in that: The Cu-Ag-Se based thermoelectric material contains Cu, Ag and Se, wherein the number of atoms of Cu, Ag and Se is 1.

5. The composite thermal conductive material according to claim 4, characterized in that: The Cu-Ag-Se based thermoelectric material is selected from the following: CuAgSe, Ni 0.02 CuAgSe and Zn 0.02 CuAgSe.

6. The composite thermal conductive material according to claim 1, characterized in that: The thickness L1 of the quasi-crystalline material matrix layer and the thickness L2 of the thermoelectric material layer satisfy the relationship: 10 mm ≤ L1 + L2 ≤ 200 mm, and L1:L2 = x:(1-x), where x is 0.6 to 0.

75.

7. The composite thermally conductive material according to claim 1, characterized in that: The projected areas of the quasi-crystal material matrix layer and the thermoelectric material layer in the thickness direction are 78 mm 2 ~7854mm 2 .

8. The composite thermally conductive material according to claim 7, characterized in that: The projection areas of the quasi-crystalline material matrix layer and the thermoelectric material layer in the thickness direction are the same.

9. The composite thermally conductive material according to any one of claims 1 to 8, characterized in that: The composite thermally conductive material further includes a thermally conductive coating layer, which is disposed between the quasi-crystalline material matrix layer and the thermoelectric material layer.

10. A method for preparing the composite thermally conductive material according to any one of claims 1 to 8, the method comprising: The metal powder of the Al-Cu-Fe based quasi-crystalline material is sequentially subjected to press forming, arc melting, first sintering and polishing to obtain a quasi-crystalline material matrix layer with a flat interface; The metal powder of the Cu-Ag-Se based thermoelectric material is sequentially subjected to press forming, arc melting, second sintering and polishing to obtain a thermoelectric material layer with a smooth interface; The quasi-crystalline material matrix layer and the thermoelectric material layer are butted together at a flat interface to obtain a solid composite thermal conductive material.

11. The method according to claim 10, characterized in that The first sintering temperature T01 satisfies: T11-T01=180°C to 220°C, where T11 represents the melting point of the metal element with the lowest melting point in the quasi-crystalline material; or The second sintering temperature T02 satisfies: T12-T02=180°C to 220°C, where T12 represents the melting point of the metal element with the lowest melting point in the Cu-Ag-Se based thermoelectric material.

12. A quasi-crystal-based solid-state composite thermal diode, comprising a thermal conductor and a columnar composite thermal conductive material according to any one of claims 1 to 9.

13. The solid-state composite thermal diode according to claim 12, characterized in that: The solid-state composite thermal diode further includes a radiation shielding layer disposed around the outer periphery of the composite thermal conductive material.

14. The solid-state composite thermal diode according to claim 13, characterized in that: The distance between the inner surface of the radiation shielding layer and the outer surface of the composite thermally conductive material is less than or equal to the radius of the composite thermally conductive material; and / or, The thickness of the radiation shielding layer is 1 mm to 1.5 mm.

15. A method for preparing the solid-state composite thermal diode according to any one of claims 12 to 14, the method comprising: Obtaining the columnar composite thermally conductive material; connecting two heat conductors to two opposite heat conducting ends of the composite heat conducting material to obtain a composite heat diode core; A radiation shielding layer is disposed around the outer periphery of the composite thermal diode core to obtain a solid-state composite thermal diode.

Images