Laminated thermoelectric-piezoelectric hybrid energy collector

Abstract

The invention provides a laminated thermoelectric-piezoelectric hybrid energy collector. The collector comprises a laminated thermoelectric conversion unit and a piezoelectric conversion unit. The thermoelectric conversion unit comprises a heat-conducting sheet, a thermoelectric material, a conductive copper sheet, a load resistor and a wire. The piezoelectric conversion unit comprises a substrate layer cooling fin, a piezoelectric plate and a mass block. According to the hybrid energy collector, the thermoelectric conversion unit and the piezoelectric conversion unit are integrated, the thermoelectric energy converter and the piezoelectric energy converter are combined into a hybrid energy collection device, environmental waste heat and environmental wind energy are converted into electric energy at the same time, the manufacturing cost of the energy collector is reduced, and meanwhile the environmental energy utilization efficiency is improved. According to the device, heat energy generated by the waste heat discharging device and environmental wind energy can be fully utilized at the same time for recycling power generation capacity, high energy collection efficiency is achieved, the device is simple and stable, the practicability of the device is improved, and good application prospects are shown in the field of energy collection.

Description

Technical Field

[0001] The invention relates to the technical field of energy harvesting, in particular to a laminated thermoelectric-piezoelectric hybrid energy harvester. Background Art

[0002] Energy issues have always been the focus of global attention. With the continuous growth of energy demand and the increasing depletion of traditional energy resources, finding sustainable and efficient ways to collect energy has become an important topic in contemporary energy research.

[0003] Thermoelectric effect and piezoelectric effect are two common energy conversion methods, which use temperature difference and mechanical strain to achieve energy conversion and collection respectively.

[0004] The research on thermoelectric materials has a long history. For a long time, due to the low thermoelectric conversion efficiency of this type of material, it has not attracted enough attention from researchers. It was not until the end of the 20th century that the ZT value (efficiency figure of merit) of this type of material broke through and began to attract more and more attention. At present, thermoelectric materials have been widely used in space exploration, waste heat recovery, ocean temperature difference power generation and new concept refrigeration devices. In actual engineering applications, it is often necessary to attach thermoelectric films to substrates to form a film / substrate laminated structure. Studies have shown that preparing thermoelectric materials into a laminated structure can not only improve the safety of the structure but also effectively improve the thermoelectric conversion efficiency. For example, literature 1 (Y. Yang, C. Lei, C.-F. Gao, and J. Li, "Asymptotic homogenization of three-dimensional thermoelectric composites," Journal of the Mechanics and Physics of Solids, vol. 76, pp. 98-126, 2019 / 03 / 01 / 2019.), literature 2 (Y. Yang, FY Ma, CH Lei, YY Liu, and JY Li, "Nonlinear asymptotic homogenization and the effective behavior of layered thermoelectric composites," Journal of the Mechanics and Physics of Solids, vol. 61, no. 8, pp. 1768-1783, 2018 / 08 / 01 / 2018.) studies have shown that preparing thermoelectric materials into a layered structure can not only improve the safety of the structure but also effectively improve the thermoelectric conversion efficiency.

[0005] In recent years, relevant scholars have also studied the piezoelectric materials used in piezoelectric energy harvesters. The researchers verified the influence of the piezoelectric properties of piezoelectric materials on the vibration of the cantilever beam by changing the structure of the base layer of the piezoelectric sheet, such as reference 3 (Kan J, Zhang M, Wang S, et al. A cantilevered piezoelectric energy harvester excited by an axially pushed wedge cam using repulsive magnets for rotary motion [J]. Smart Materials and Structures, 2021, 30 (6): 065009). The researchers proposed a new cantilevered piezoelectric energy harvester based on axially pushed wedge cam excitation of repulsive magnets, which can realize unidirectional deformation and limited amplitude of the piezoelectric cantilever beam, so the harvester can maintain a relatively stable output voltage over a wide range of rotation speeds.

[0006] However, single thermoelectric conversion or piezoelectric conversion often has problems such as low energy utilization, complex structure, and high cost. Therefore, it is necessary to provide a laminated thermoelectric-piezoelectric hybrid energy harvester that can efficiently and comprehensively utilize waste heat and mechanical energy. Summary of the invention

[0007] The present invention overcomes the shortcomings of the prior art and provides a laminated thermoelectric-piezoelectric hybrid energy harvester that can efficiently and comprehensively utilize waste heat and mechanical energy. The device realizes the simultaneous collection and conversion of waste heat and ambient wind energy through the integrated design of the thermoelectric conversion unit and the piezoelectric conversion unit, greatly improving the energy collection efficiency. The device has a simple structure, does not require an external power supply, has a high degree of automation and is easy to operate, showing good application prospects.

[0008] In order to solve the above technical problems, the solution provided by the present invention is to provide a laminated thermoelectric-piezoelectric hybrid energy harvester, including a thermoelectric conversion unit and a piezoelectric conversion unit, wherein the thermoelectric conversion unit is a laminated thermoelectric conversion unit, including:

[0009] The heat conducting sheet is arranged in multiple layers horizontally from top to bottom, and multiple conductive copper sheets connected to the heat conducting sheet are arranged in the gap between each two layers horizontally, and the heat conducting sheet at the bottom layer exchanges heat with the heat source, so that the heat of the multiple layers of heat conducting sheets decreases from bottom to top;

[0010] Thermoelectric materials are provided in plurality, and the plurality of thermoelectric materials are arranged in each gap at intervals along the horizontal direction, and connected to a plurality of conductive copper sheets in the gap, two adjacent thermoelectric materials are P-type semiconductor material and N-type semiconductor material, each P-type semiconductor material and each N-type semiconductor material and a conductive copper sheet form a pair of PN thermocouples, and the plurality of PN thermocouple pairs form an electrical series relationship in the gap;

[0011] Piezoelectric conversion unit, comprising:

[0012] The base layer heat sink is provided in plurality, and the plurality of base layer heat sinks are vertically arranged on the topmost heat conducting sheet and connected thereto;

[0013] A plurality of piezoelectric sheets are provided, and each piezoelectric sheet is arranged on both sides of each base layer heat sink and is tightly connected thereto.

[0014] Preferably, the operating temperatures of the plurality of thermoelectric materials located in each gap decrease successively from bottom to top.

[0015] Preferably, the conductive copper sheets respectively connected to the bottom of each heat conducting sheet in two adjacent gaps can be connected through a first wire, and the conductive copper sheets respectively connected to the bottom of each heat conducting sheet in two adjacent gaps can be connected to a load resistor or an electrical appliance through a second wire.

[0016] Preferably, a mass block is provided on the top of the base layer heat sink.

[0017] Preferably, the thermally conductive sheet is made of a dielectric material or a semiconductor material with high thermal conductivity, and an insulating layer is provided on the surface of the thermally conductive sheet, and the insulating layer is silica gel.

[0018] Preferably, the thickness of the conductive copper sheet is 0.005 mm to 0.1 mm.

[0019] Preferably, the P-type semiconductor material is any one of bismuth telluride, lead antimonide or bismuth selenide, and the N-type semiconductor material is any one of tin sulfide, aluminum nitride or lead telluride.

[0020] Preferably, the piezoelectric sheet has a thickness smaller than that of the base layer heat sink.

[0021] Preferably, the material of the base layer heat sink may be a copper-aluminum alloy, and the material of the piezoelectric sheet includes but is not limited to one of piezoelectric ceramics, barium titanate or lead zirconate titanate.

[0022] Preferably, the base layer heat sink is fixedly connected to the topmost layer of heat conducting sheet.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention designs a laminated thermoelectric conversion unit by designing a thermoelectric conversion unit structure and applying the lamination concept to the thermoelectric conversion unit structure. The thermoelectric materials contained in the laminated thermoelectric conversion unit can be thermoelectric materials with the same operating temperature or thermoelectric materials with operating temperatures decreasing from bottom to top. The laminated thermoelectric conversion unit can make full use of the thermoelectric properties of the thermoelectric materials and maximize the thermoelectric parameters, thereby improving the overall thermoelectric conversion efficiency. The laminated thermoelectric layer structure realizes a compact and efficient design by integrating thermal conductive sheets, thermoelectric materials and conductive copper sheets. This integrated design helps to reduce the volume and weight of the device while improving the energy conversion efficiency and reliability of the device.

[0025] 2. The present invention uses the heat sink of the thermoelectric conversion unit as the base layer of the piezoelectric conversion unit by design, and fixes the piezoelectric sheet on both sides, so that heat energy and wind energy can be converted into electrical energy at the same time, thereby realizing the integration of the thermoelectric conversion unit and the piezoelectric conversion unit into a hybrid energy collector. The base layer heat sink vibrates under the external wind force or other mechanical action, and the vibration energy is transmitted through the tightly fixed piezoelectric sheet and converted into electrical energy, thereby realizing electrical energy output based on the piezoelectric effect.

[0026] 3. The present invention is designed to install a mass block at the end of the base layer heat sink. The mass block can amplify and concentrate the vibration amplitude of the base layer heat sink caused by the ambient wind energy through its design. These vibration amplitudes are transmitted to the piezoelectric sheet through the base layer heat sink, thereby enhancing the deformation of the piezoelectric sheet and improving the conversion efficiency of ambient wind energy into electrical energy. In the entire system, the design of a high-density metal block amplifies and concentrates the vibration energy to ensure that the piezoelectric conversion unit can operate efficiently and stably, thereby improving the energy collection efficiency of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of a laminated thermoelectric-piezoelectric hybrid energy harvester provided by the present invention;

[0028] Figure 2 It is a side view of a laminated thermoelectric-piezoelectric hybrid energy harvester provided by the present invention.

[0029] Description of reference numerals:

[0030] 1. Thermoelectric conversion unit, 2. Piezoelectric conversion unit, 11. Thermal conductive sheet, 12. First thermoelectric material, 13. Second thermoelectric material, 14. Conductive copper sheet, 15. Load resistor, 16. Wire, 21. Base layer heat sink, 22. Piezoelectric sheet, 23. Mass block. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] The inventors found that since the energy harvester provided by the prior art is a single thermoelectric converter or piezoelectric converter, and the two single converters can only collect energy from two energy sources separately, and the waste heat environment is usually accompanied by wind energy, deploying thermoelectric converters and piezoelectric converters at the same time is not only costly but also occupies a large space.

[0033] In view of this, the present invention provides a laminated thermoelectric-piezoelectric hybrid energy harvester, which realizes the simultaneous collection and conversion of waste heat and ambient wind energy through the integrated design of thermoelectric conversion unit and piezoelectric conversion unit, greatly improving the energy collection efficiency. The device has a simple structure, does not require an external power supply, has a high degree of automation and is easy to operate, showing good application prospects.

[0034] The present invention provides a laminated thermoelectric-piezoelectric hybrid energy harvester, comprising a thermoelectric conversion unit and a piezoelectric conversion unit, wherein the thermoelectric conversion unit is a laminated thermoelectric conversion unit 1, and the laminated thermoelectric conversion unit 1 comprises:

[0035] The heat conducting sheet 11 is arranged in multiple layers in the horizontal direction from top to bottom, and there is a gap between every two layers of the heat conducting sheet 11. Multiple conductive copper sheets 14 are arranged in the horizontal direction in each gap, and each conductive copper sheet 14 is connected to each heat conducting sheet 11. The heat conducting sheet 11 at the bottom layer exchanges heat with the heat source, so that the heat of the multiple layers of the heat conducting sheet 11 decreases from bottom to top.

[0036] Thermoelectric materials are provided in a plurality, and the plurality of thermoelectric materials are arranged in each gap at intervals along the horizontal direction, and are connected to a plurality of conductive copper sheets 14 located in each gap, and two adjacent thermoelectric materials are respectively a P-type semiconductor material and an N-type semiconductor material, and the P-type semiconductor material and the N-type semiconductor material each form a PN thermocouple pair with a conductive copper sheet 14, and the plurality of PN thermocouple pairs form an electrical series relationship in the gap.

[0037] The piezoelectric conversion unit 2 comprises:

[0038] The base layer heat sink 21 is provided in plurality, and the plurality of base layer heat sinks 21 are arranged vertically, and the bottom of each base layer heat sink 21 is connected to the topmost heat conducting sheet 11;

[0039] A plurality of piezoelectric sheets 22 are provided, and each piezoelectric sheet 22 is provided on both sides of each base layer heat sink 21 and is tightly connected thereto.

[0040] The present invention integrates the thermoelectric conversion unit 1 and the piezoelectric conversion unit 2, which not only realizes the heat exchange temperature difference power generation capacity of the thermoelectric material, but also enhances the conversion of environmental wind energy into electrical energy, thereby significantly improving the environmental energy utilization efficiency.

[0041] The thermal conductive sheet 11 is not only the base of the piezoelectric conversion unit to ensure structural stability, but also the heat sink of the laminated thermoelectric conversion unit. Due to its high thermal conductivity, it can quickly transfer heat from the heat source to the environment to ensure the heat dissipation effect of the thermoelectric conversion unit. When it serves as a bridge between the laminated thermoelectric conversion unit 1 and the piezoelectric conversion unit 2, the integration between the laminated thermoelectric conversion unit 1 and the piezoelectric conversion unit 2 is realized.

[0042] The shape of the thermoelectric material can be rectangular, square or any other shape, which can be selected according to actual needs.

[0043] like Figure 1-2 As shown, when the heat conducting sheet 11 is three-layered, the heat conducting sheet 11 includes a first heat conducting sheet, a second heat conducting sheet and a third heat conducting sheet from bottom to top. Two gaps are formed between the first heat conducting sheet, the second heat conducting sheet and the third heat conducting sheet. The thermoelectric material provided in each gap can be the same or two. Two different thermoelectric materials are selected here, the first thermoelectric material 12 and the second thermoelectric material 13, because the thermoelectric material with the best working temperature adapted to the different working temperatures and thermoelectric parameters can be selected.

[0044] The first thermal conductive sheet is a base layer, the bottoms of the plurality of first thermoelectric materials 12 are fixed on the first thermal conductive sheet through a conductive copper sheet 14, and the tops of the plurality of first thermoelectric materials 12 are fixed to the second thermal conductive sheet through the conductive copper sheet 14; the bottoms of the plurality of second thermoelectric materials 13 are fixed on the second thermal conductive sheet through the conductive copper sheet 14, and the tops of the plurality of second thermoelectric materials 13 are connected to the third thermal conductive sheet through the conductive copper sheet 14, and the third thermal conductive sheet is connected to the base layer heat sink 21 of the piezoelectric conversion unit 2; the two adjacent first thermoelectric materials 12 located in the same gap and the two adjacent second thermoelectric materials 13 located in the same gap can form a thermocouple connected by a P-type semiconductor material and an N-type semiconductor material with the conductive copper sheet 14, and this potential difference can be used to drive current to realize the conversion of thermal energy into electrical energy. The plurality of thermocouple pairs form an electrical series and thermal parallel relationship, so that the first thermal conductive sheet, the second thermal conductive sheet and the third thermal conductive sheet transfer the heat of the heat exchange between the first thermal conductive sheet and the heat source in parallel layer by layer through the plurality of thermoelectric materials.

[0045] Only when the first thermoelectric material 12 and the second thermoelectric material 13 form a thermocouple pair can they be used as a power generation device to convert thermal energy (temperature difference on both sides) into electrical energy. A thermocouple pair is composed of a thermoelectric leg made of a P-type thermoelectric material and a thermoelectric leg made of an N-type thermoelectric material connected by a small piece of copper. There is no clear requirement for how many pairs of thermocouple pairs are laid in the gap. One or more can be done, and it can be determined by yourself according to the structural size. Generally, the more thermocouple pairs per layer, the greater the power generation. Thermocouple pairs can be understood as batteries one by one. The more they are connected in series, the greater the power generation.

[0046] "Thermal parallel and electrical series connection" refers to the thermocouple pairs of each layer, that is, "thermal parallel and electrical series connection" is a description of the working state of each layer of thermocouple pairs, and the potential difference is generated by the temperature difference on both sides of the thermocouple pairs. That is to say, for each layer of thermocouple pairs, the temperature difference on both sides of each layer of thermocouple pairs is the same, and each layer of thermocouple pairs can be connected in series to a circuit through wires, so their working state is called "thermal parallel and electrical series connection".

[0047] The operating temperatures of the thermoelectric materials in the thermoelectric conversion unit structure provided by the present invention decrease in sequence, and of the two adjacent thermoelectric materials, the operating temperature of the thermoelectric material at the bottom is higher than that of the upper thermoelectric material. The thermoelectric conversion parameter of each thermoelectric material is a physical property related to temperature, and different materials have different optimal operating temperatures. This design can select thermoelectric materials with the optimal operating temperature that are compatible with different operating temperatures and thermoelectric parameters.

[0048] A plurality of thermoelectric materials capable of forming a PN junction are connected in series on one side of the conductive copper sheet 14, and the other side of the conductive copper sheet 14 is fixed on the heat conductive sheet 11. Since the copper sheet has good thermal conductivity, it helps to evenly distribute heat, thereby improving the thermoelectric conversion efficiency. The conductive copper sheet 14 is a good conductive material for conducting current between thermoelectric materials. The thermoelectric material generates a voltage difference after being heated, and the current flows in the loop through the conductive copper sheet 14 to supply energy to the load.

[0049] The thermal conductive sheet 11 is used to efficiently conduct the heat generated by the heat source to the multiple first thermoelectric materials 12 and the multiple second thermoelectric materials 13. Since the thermal conductive sheet 11 has a high thermal conductivity, it can quickly transfer heat from the heat source to the multiple first thermoelectric materials 12 and the multiple second thermoelectric materials 13, thereby forming a temperature difference and promoting the generation of electric energy in the thermoelectric conversion unit 1. And the bottom layer of the thermal conductive sheet 11 serves as a supporting structure for the multiple first thermoelectric materials 12, which laminates and stacks the two different thermoelectric materials together so that they can be in close contact and work effectively. The thermal conductive sheet 11 provides structural stability for the entire thermoelectric conversion unit 1, ensuring that the thermoelectric material and the conductive copper sheet 14 can be firmly fixed together without displacement or loosening due to mechanical vibration or thermal expansion.

[0050] Thermoelectric conversion unit does not necessarily include wires and thermal resistors. Thermoelectric unit can convert temperature gradient into open circuit voltage, which can be powered by connecting it to a resistor (or electrical appliance) through a wire.

[0051] Connecting the piezoelectric sheet 22 to the topmost base heat sink 21 allows the piezoelectric sheet 22 to better sense the mechanical vibration of the base heat sink 21. The base heat sink 21 vibrates under the action of the external wind, and the vibration energy is transmitted through the tightly fixed piezoelectric sheet 22 and converted into electrical energy, thereby enhancing the piezoelectric effect and improving the electrical energy output. The piezoelectric sheet 22 collects the thermal stress deformation energy of the base heat sink 21 and the swing amplitude energy of the base heat sink 21 under the external wind energy, and converts the thermal stress deformation and environmental wind energy into electrical energy.

[0052] The base layer heat sink 21 effectively dissipates heat and helps maintain the temperature difference between the first thermoelectric materials 12 and the second thermoelectric materials 13, thereby enhancing the thermoelectric effect and improving the power output of the thermoelectric conversion unit. The base layer heat sink 21 also serves as the base layer of the piezoelectric sheet 22.

[0053] Specifically, the operating temperatures of multiple thermoelectric materials in each gap decrease from bottom to top. This is the best setting method for thermoelectric materials. The optimal operating temperatures of multiple thermoelectric materials in each gap decrease, adapting to the temperature gradient and improving the overall performance of the laminated thermoelectric-piezoelectric hybrid energy harvester.

[0054] Specifically, the two layers of conductive copper sheets 14 respectively connected to the bottom of each thermal conductive sheet 11 in two adjacent gaps can be connected through a first wire, and the two layers of conductive copper sheets 14 respectively connected to the bottom of each thermal conductive sheet 11 in two adjacent gaps can be connected to the load resistor 15 or the power supply through a second wire 16.

[0055] When the thermal conductive sheet 11 is three-layered, multiple first thermoelectric materials 12 and multiple second thermoelectric materials 13 are sequentially set from bottom to top in the gap between two adjacent layers of thermal conductive sheets 11, wherein multiple first thermoelectric materials 12 and multiple second thermoelectric materials 13 generate electromotive force through temperature difference, and convert thermal energy into electrical energy through load resistor 15, and wire 16 transmits the generated electrical energy to an external load or energy storage device, so as to realize the recovery, collection and effective utilization of waste heat. Or multiple first thermoelectric materials 12 and multiple second thermoelectric materials 13 generate electromotive force through temperature difference and generate electrical energy through wire, which is equivalent to power supply.

[0056] Specifically, a mass block 23 is provided on the top of the base layer heat sink 21 .

[0057] The mass block 23 is connected to the end of the base layer heat sink 21 and its material can be a high-density metal block. It can enhance the mechanical vibration effect of the base layer heat sink 21 by amplifying and concentrating the vibration energy and transmitting stress, thereby improving the piezoelectric energy collection efficiency.

[0058] In addition, the design of the high-density metal block 23 connected to the end of the base layer heat sink 21 can amplify and concentrate the mechanical vibration of the base layer heat sink 21 caused by the external wind energy. These vibration energies are transmitted to the piezoelectric sheet 22 through the base layer heat sink 21, thereby enhancing the deformation of the piezoelectric sheet 22 and improving the conversion efficiency of environmental wind energy into electrical energy. The high-density metal block 23 concentrates the force applied by the outside on the piezoelectric sheet 22 through its shape design. This concentration of force helps to more effectively utilize mechanical stress and increase the deformation amplitude of the piezoelectric sheet, thereby improving the energy conversion efficiency. The high-density metal block 23 helps to effectively transfer the amplitude generated by the environmental wind energy on the base layer heat sink 21 to the piezoelectric sheet, so that the piezoelectric sheet 22 can make full use of these stresses for electrical energy conversion.

[0059] Specifically, the heat conducting sheet 11 is made of a dielectric material or semiconductor material with high thermal conductivity. The material has good thermal conductivity and can exchange and conduct heat with a heat source. In addition, the heat conducting sheet 11 is made of a dielectric material or semiconductor material with high thermal conductivity, which can also ensure effective conduction of heat energy.

[0060] Specifically, in order to prevent short circuit, an insulating layer is provided on the surface of the heat conducting sheet 11, and the insulating layer is silica gel.

[0061] Specifically, the thickness of the conductive copper sheet 14 is 0.005 mm to 0.1 mm.

[0062] The conductive copper sheet 14 is made of copper, which has high conductivity. The conductive copper sheet 14 should not be too thick, otherwise it will affect the heat conduction between the thermoelectric material and the thermal conductive sheet 11, and the electron transport between the electrical material and the external circuit. The conductive copper sheet 14 should not be too thin, otherwise it will affect the mechanical properties of the thermoelectric conversion unit 1 and reduce the stability of the thermoelectric conversion unit 1.

[0063] Specifically, the P-type semiconductor material is any one of bismuth telluride, lead antimonide or bismuth selenide, and the N-type semiconductor material is any one of tin sulfide, aluminum nitride or lead telluride.

[0064] The P-type semiconductor material can be one of bismuth telluride, lead antimonide or bismuth selenide and bismuth and antimony alloys. The P-type semiconductor material can adjust its conductivity and Seebeck coefficient. In engineering applications, these alloys are often used to prepare composite thermoelectric materials to improve their overall performance.

[0065] N-type semiconductor materials can be tin sulfide, aluminum nitride or lead telluride. These materials have a high Seebeck coefficient and moderate electrical conductivity, and are suitable for thermoelectric conversion in the low to medium temperature range. According to the Seebeck effect, when a thermoelectric material is subjected to thermal shock, the energy level distribution of electrons in the thermoelectric material changes. This causes electrons to move from the high temperature end to the low temperature end when a temperature gradient exists, thereby generating a potential difference at both ends of the material.

[0066] Specifically, the thickness of the piezoelectric sheet 22 is smaller than that of the base layer heat sink 21 .

[0067] The thickness of the piezoelectric sheet 22 is smaller than that of the base layer heat sink 21 , so that the energy generated by the base layer heat sink 21 caused by external mechanical vibration can be better collected.

[0068] Specifically, the material of the base layer heat sink 21 can be copper-aluminum alloy, wherein the copper-aluminum alloy combines the advantages of copper and aluminum, provides a balanced thermal conductivity and lightweight option, and is suitable for use in applications that require higher thermal conductivity but also require lightweight. The material of the piezoelectric sheet 22 includes but is not limited to one of piezoelectric ceramics, barium titanate or lead zirconate titanate.

[0069] Specifically, the base layer heat sink 21 is tightly connected to the topmost thermal conductive sheet 11 by welding or other fixing methods to increase the heat dissipation effect of the thermoelectric conversion unit 1. The base layer heat sink 21 is tightly connected to the outside of the thermal conductive sheet 11 to increase the heat dissipation effect of the thermoelectric conversion unit 1. The design also reduces the cold end temperature of the thermoelectric conversion unit 1 in disguised form, thereby improving the thermoelectric conversion efficiency of the thermoelectric conversion unit 1.

[0070] Working principle:

[0071] When the laminated thermoelectric-piezoelectric hybrid energy harvester of the present invention is placed near a waste heat source, the heat conducting sheet 11 in the thermoelectric conversion unit 1 absorbs heat first. Figure 1-2 The laminated thermoelectric-piezoelectric hybrid energy harvester includes three layers of heat conducting sheets 11. A plurality of first thermoelectric materials 12 and a plurality of second thermoelectric materials 13 are placed from bottom to top in the gap formed by the three layers of heat conducting sheets 11. The plurality of first thermoelectric materials 12 and the plurality of second thermoelectric materials 13 are connected to each layer of heat conducting sheets 11 through conductive copper sheets 14. In addition, the plurality of first thermoelectric materials 12 and the plurality of second thermoelectric materials 13 are composed of P-type semiconductor materials and N-type semiconductor materials. Two adjacent P-type semiconductor materials and N-type semiconductor materials in each gap form a thermocouple pair. After the plurality of thermocouple pairs are connected in series, the plurality of first thermoelectric materials 12 and the plurality of second thermoelectric materials 13 will generate a thermoelectric potential under the action of the temperature difference. At this time, the conductive copper sheet 14 introduces the current of the thermocouple pair into the load resistor 15, and outputs the electric energy through the wire 16.

[0072] At the same time, the base layer heat sink 21 of the piezoelectric conversion unit 2 absorbs and dissipates heat, causing the piezoelectric sheet 22 to generate thermal stress deformation. Under the action of external wind force, the piezoelectric sheet 22 generates mechanical vibration and converts mechanical energy into electrical energy using the piezoelectric effect. The two conversion units work together to significantly improve the energy collection efficiency.

[0073] The present invention combines a thermoelectric energy converter and a piezoelectric energy converter into a hybrid energy collection device, which can simultaneously convert environmental waste heat and environmental wind energy into electrical energy, thereby reducing the manufacturing cost of the energy collector and improving the environmental energy utilization efficiency.

[0074] The laminated thermoelectric-piezoelectric hybrid energy harvester of the present invention can fully utilize the heat energy generated by the waste heat discharge device and the ambient wind energy to recover and generate electricity, has a high energy collection efficiency, and the device has a stable structure and is easy to manufacture and maintain, which greatly improves the practicality of the device and shows good application prospects in the field of energy collection.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A laminated thermoelectric-piezoelectric hybrid energy harvester, comprising a thermoelectric conversion unit and a piezoelectric conversion unit, characterized in that: The thermoelectric conversion unit is a laminated thermoelectric conversion unit (1), comprising: The heat conducting sheet (11) is arranged in multiple layers in the horizontal direction from top to bottom, and multiple conductive copper sheets (14) connected to the heat conducting sheets (11) are arranged in the horizontal direction in the gap between each two layers of the heat conducting sheets (11), and the heat conducting sheet (11) at the bottom layer exchanges heat with the heat source, so that the heat of the multiple layers of the heat conducting sheets (11) decreases from bottom to top; Thermoelectric materials are provided in plurality, and the plurality of thermoelectric materials are arranged in each gap at intervals along the horizontal direction and connected to a plurality of conductive copper sheets (14) in the gap, two adjacent thermoelectric materials are a P-type semiconductor material and an N-type semiconductor material, each P-type semiconductor material and each N-type semiconductor material and a conductive copper sheet (14) form a pair of PN thermocouples, and the plurality of PN thermocouple pairs form an electrical series relationship in the gap; A piezoelectric conversion unit (2), comprising: A plurality of base layer heat sinks (21) are provided, and the plurality of base layer heat sinks (21) are vertically arranged on the topmost heat conducting sheet (11) and connected thereto; A plurality of piezoelectric sheets (22) are provided, and each piezoelectric sheet (22) is provided on both sides of each base layer heat sink (21) and is tightly connected thereto.

2. A laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The operating temperatures of the multiple thermoelectric materials located in each gap decrease from bottom to top.

3. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The conductive copper sheets (14) respectively connected to the bottom of each heat conducting sheet (11) in two adjacent gaps can be connected via a first wire, and the conductive copper sheets (14) respectively connected to the bottom of each heat conducting sheet (11) in two adjacent gaps can be connected to a load resistor (15) or an electrical appliance via a second wire (16).

4. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: A mass block (23) is provided on the top of the base layer heat sink (21).

5. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The heat conducting sheet (11) is made of a dielectric material or a semiconductor material with high thermal conductivity, and an insulating layer is provided on the surface of the heat conducting sheet (11), wherein the insulating layer is silica gel.

6. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The thickness of the conductive copper sheet (14) is 0.005 mm to 0.1 mm.

7. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The P-type semiconductor material is any one of bismuth telluride, lead antimonide or bismuth selenide, and the N-type semiconductor material is any one of tin sulfide, aluminum nitride or lead telluride.

8. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The thickness of the piezoelectric sheet (22) is smaller than that of the base layer heat sink (21).

9. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The material of the base layer heat sink (21) may be a copper-aluminum alloy, and the material of the piezoelectric sheet (22) includes but is not limited to one of piezoelectric ceramics, barium titanate or lead zirconate titanate.

10. The laminated thermoelectric-piezoelectric hybrid energy harvester according to claim 1, characterized in that: The base layer heat sink (21) is fixedly connected to the top layer heat conducting sheet (11).

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