Passive high-performance pyroelectric thermodynamic cycle energy collection system and application

Abstract

The invention provides a passive high-performance pyroelectric thermodynamic cycle energy collection system and application, and belongs to the technical field of energy storage. According to the system, a dielectric elastomer capacitor and a ferroelectric capacitor are utilized to form a double-capacitor structure, and a ferroelectric charge pump circuit is matched to realize pyroelectric thermodynamic cycle passive high-performance energy collection. The ferroelectric capacitor constructs the self-pumping electric characteristic of the charge pump circuit, so that the system does not need to be externally connected with a high-voltage power supply, spontaneous high voltage is realized, and a pyroelectric thermodynamic cycle is effectively constructed; spontaneous shuttling of charges is realized based on an alternating current mode of double-capacitor charges, so that effective operation of a high-performance thermodynamic cycle is guaranteed, dependence on an active switch is reduced, and efficient and continuous energy output is realized; based on the system, the temperature of the dielectric elastomer capacitor and the temperature of the ferroelectric charge pump circuit are synchronously controlled through the heat exchange structure, then a synergistic effect is formed, larger capacitance change is provided, the energy collection capacity of the system is enhanced, and the system has the advantages of being low in cost, simple in structure and high in applicability.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a passive high-performance pyroelectric thermodynamic cycle energy collection system and its application. Background Art

[0002] Low-grade thermal energy (below 100-230℃) is widely present in waste heat emission occasions such as industrial production and transportation vehicles, and the total amount is huge (about 1.1X105 TW). At present, the research on its recycling and utilization is mainly focused on three directions, namely organic Rankine cycle, thermoelectric materials and pyroelectric materials. Based on the perspective of Carnot efficiency, the latter has the most application prospects. Ferroelectric materials with pyroelectric effect are solid materials with mature preparation technology and low cost. They can generate current in the external circuit under temperature fluctuation conditions, but the energy conversion efficiency of ferroelectric materials is usually lower than 1% Carnot efficiency directly through thermal stimulation discharge. For this reason, some researchers have constructed a pyroelectric thermodynamic cycle (i.e., Olson cycle) of ferroelectric materials, whose theoretical conversion efficiency can reach 50% Carnot efficiency. Therefore, the pyroelectric thermodynamic cycle has received extensive attention and research in the field of thermal energy collection.

[0003] In 2022, Emmanuel Defay published a paper in Nature, successfully achieving an energy conversion of 11.2 J per cycle at room temperature through a relaxor-type ferroelectric thick film stack module in a liquid flow heat exchange mode, but there are still problems in the face of the next step of practical development. The traditional pyroelectric thermodynamic cycle system mainly consists of four parts: (1) Ferroelectric capacitor, which is a capacitor composed of ferroelectric materials, is the core of energy conversion and is equivalent to the working fluid of traditional thermodynamics; (2) High voltage source, as a charge source, it acts as a charge source in the pyroelectric thermodynamic cycle to maintain the voltage state of the ferroelectric capacitor; (3) Heat exchange structure, which makes the ferroelectric capacitor form a temperature fluctuation change and establishes the required temperature change conditions for the cycle process; (4) Active switching unit module, which is used to control temperature changes, voltage changes, and charge input and output to ensure the formation of different types of thermodynamic cycles. The traditional pyroelectric thermodynamic cycle process is based on "active" energy harvesting established in a constant voltage mode, that is, an external high-voltage power supply must be added to maintain the high-voltage state of the ferroelectric material and an active control module must be added to control the cycle mode, resulting in additional energy consumption and inability to effectively harvest low-grade thermal energy. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and provide a passive high-performance pyroelectric thermodynamic cycle energy harvesting system and application. The "self-pumping" characteristics of the self-bias circuit can be used to achieve high-voltage passivity in this system; based on the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure, the power output of the pyroelectric thermodynamic cycle can be made passive.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The first purpose of the present invention is to provide a passive high-performance pyroelectric thermodynamic cycle energy collection system, including a dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure and a heat exchange structure, the heat exchange structure provides a heat source or a cold source for the ferroelectric capacitor, the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure includes a dielectric elastomer capacitor and a self-bias circuit, a plurality of ferroelectric capacitors are arranged on the self-bias circuit, the heat source and the cold source provide heat or cold to the plurality of ferroelectric capacitors, the self-pumping electrical characteristics of the self-bias circuit realize dynamic high-voltage changes of the ferroelectric capacitor; the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure can realize the passivity of the electric energy output of the pyroelectric thermodynamic cycle.

[0006] Furthermore, a voltage stabilizing diode is arranged in parallel on the self-bias circuit, and the self-bias circuit and the voltage stabilizing diode constitute a self-bias voltage stabilizing circuit. The self-bias circuit is composed of a plurality of ferroelectric capacitors and internal diodes, and the ferroelectric capacitors are put into a series-parallel mode by turning on and off the internal diodes.

[0007] Furthermore, the self-bias circuit includes four ferroelectric capacitors and five internal diodes, and the series-parallel state of the internal capacitors is changed by turning on and off the internal diodes. The four ferroelectric capacitors are C1, C2, C3 and C4, and the five internal diodes are D1, D2, D3, D4 and D5.

[0008] Furthermore, the five internal diodes are connected in sequence and in series with the Zener diode, C1 is connected on the branch between D1 and D2, C2 is connected on the branch between D2 and D3, C3 is connected on the branch between D3 and D4, and C4 is connected on the branch between D4 and D5, and C1, C2, C3 and C4 are all connected in parallel with the Zener diode.

[0009] Furthermore, the dielectric elastomer capacitor is connected in series with an external load and then connected in parallel on both sides of the self-biased voltage stabilization circuit; the dielectric elastomer capacitor includes a dielectric elastomer and variable electrodes on both sides thereof.

[0010] Furthermore, the external load is a resistor, a light emitting diode, or a charging load consisting of a rectifier bridge and a capacitor.

[0011] Furthermore, the dielectric elastomer capacitor is a stretchable elastomer capacitor, which is composed of a dielectric elastomer and variable electrodes on both sides. The dielectric elastomer is a stretchable elastic material selected from any one of silicone rubber, block copolymer, and thermoplastic bioplastics, and the variable electrodes on both sides are selected from any one of conductive silicone grease, silver nanowires, hydrogel, and ion conductors.

[0012] Furthermore, the voltage stabilizing diode releases the excess charge in the system to achieve the purpose of stabilizing the system.

[0013] Furthermore, the ferroelectric capacitor is made of a ferroelectric material having a pyroelectric effect. When the temperature changes, the ferroelectric capacitor value will change, the capacitance value will decrease when the temperature rises, and the capacitance value will increase when the temperature drops.

[0014] The second object of the present invention is to provide an energy storage device, comprising the above-mentioned passive high-performance pyroelectric thermodynamic cycle energy collection system.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a passive high-performance pyroelectric thermodynamic cycle energy collection system. The self-pumping characteristics of a charge pumping circuit constructed by a ferroelectric capacitor can enable the system to achieve a constant charge and high-voltage state during operation. The dynamic high-voltage change of the ferroelectric capacitor can be achieved without a bulky external high-voltage power supply to supplement the charge, thereby effectively constructing a passive thermodynamic pyroelectric cycle. The characteristics that the charge can spontaneously shuttle between a dual-capacitor structure in an alternating current form as the capacitance changes in an alternating current mode are utilized to ensure the effective circulation of the passive high-performance thermodynamic cycle, achieve efficient and continuous energy output, and do not require complex active switch components to control charge charging and discharging, thereby reducing dependence on an external power supply. The characteristics of integrating an elastomer capacitor and a ferroelectric pumping circuit into a heat exchange structure to achieve force-heat dual-field coupling are utilized to achieve force field synchronous control of the temperature change of the dielectric elastomer capacitor and the ferroelectric charge pumping circuit, thereby forming a synergistic effect, efficiently constructing a thermodynamic cycle to provide a greater capacitance change for the system, and enhancing the energy collection capability of the system. The system has the characteristics of low cost, simple structure, and high applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the pyroelectric thermodynamic cycle energy harvesting system of the prior art; Figure 2 It is a schematic diagram of the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure of the present invention; Figure 3 This is a schematic diagram of the thermodynamic cycle principle in this example of the present invention; Figure 4 A schematic diagram of the structure of a passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention; Figure 5 It is a schematic diagram of the structure of this embodiment of the present invention; Figure 6 is a structural diagram of a self-bias circuit of this embodiment of the present invention; Figure 7 This is the schematic diagram of the self-bias circuit when the force field and thermal field work; Figure 8 It is the system output current curve and the temperature change curve of the temperature field when the pyroelectric thermodynamic cycle system is working; Fig. 9 It is the energy density diagram of the pyroelectric thermodynamic cycle system; Fig.10 Another structural schematic diagram shown in an embodiment of the present invention.

[0017] In the figure: 1, heat source; 2, dielectric elastomer capacitor; 21, dielectric elastomer; 22, variable electrode; 3, self-bias voltage regulator circuit; 31, voltage regulator diode; 32, self-bias circuit; 4, cold source; 5, external load; 6, ferroelectric capacitor; 7, internal diode; 8, solenoid valve; 9, silicone pipe; 10, waste liquid container; 11, computer; 12, thermocouple; 13, constant current pump; 14, high voltage power supply. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0019] refer to Figure 1 , is a structural diagram of a conventional pyroelectric thermodynamic cycle energy harvesting system of the prior art. The defects of this system are as follows: (1) The establishment of the thermodynamic cycle is inseparable from the high-voltage power supply 14 used to supplement the charge to maintain the dynamic high-voltage change of the ferroelectric material under the action of the temperature field to achieve an effective thermodynamic cycle, which greatly hinders its practical application, especially for decentralized distributed low-grade thermal energy; (2) The complex active switch unit modules 11 and 12 are used to control the input and output of the charge to match the cycle temperature, which requires additional manufacturing and maintenance, which increases the cost of the system. At the same time, an additional DC power supply is required, which causes the energy consumed to be greater than the energy collected, thereby limiting the efficiency of the system.

[0020] Based on the above problems, the inventors have proposed a passive high-performance pyroelectric thermodynamic cycle energy harvesting system. Due to the good dielectric and mechanical properties of the dielectric elastomer, it can operate under high voltage and large charge. The capacitance value of the dielectric elastomer changes with deformation. Based on the capacitance change characteristics of the "dielectric elastomer-ferroelectric capacitor" dual capacitor structure and the characteristics of the charge pump circuit that can pump charge and increase voltage, the present invention has designed the following measures to improve its limitations and increase system efficiency: (1) Using ferroelectric capacitors to construct a charge pump circuit can enable the system to achieve constant charge and high voltage during operation. Without an external high-voltage power supply, the dynamic high-voltage change of the ferroelectric capacitor can be achieved, thereby effectively constructing a charge pump circuit. Construct a passive thermodynamic pyroelectric cycle; (2) The AC mode charge can spontaneously shuttle through the dual capacitor structure in AC mode as the capacitance changes, ensuring the effective circulation of the passive high-performance thermodynamic cycle and achieving efficient and continuous energy output. There is no need for active switches to control charging and discharging, reducing dependence on external power sources; (3) The elastomer capacitor and ferroelectric pumping circuit are introduced into the heat exchange structure, and through the force-heat dual field coupling, the force field is used to synchronously control the temperature change of the dielectric elastomer capacitor and the ferroelectric charge pumping circuit, thereby forming a synergistic effect, efficiently constructing a thermodynamic cycle to provide the system with a larger capacitance change and enhance the system's energy collection capability. This system has the characteristics of low cost, simple structure, and high applicability.

[0021] refer to Figure 2 , which is a schematic diagram of the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure of the present invention. The heat exchange structure is combined with the dual capacitor structure to form a pyroelectric thermodynamic cycle energy collection system. The dual capacitor structure of the dielectric elastomer capacitor-ferroelectric capacitor is established. Under the action of external force, the dielectric elastomer capacitor will deform, according to the formula , where C, ε, S and d represent the capacitance value, dielectric constant, area and thickness of the dielectric elastomer capacitor, respectively. The capacitance value of the dielectric elastomer capacitor increases when it is stretched and decreases when it is contracted. When the dual capacitor structure composed of the ferroelectric capacitor and the dielectric elastomer capacitor works, its charge is constant, and the change in capacitance causes the charge to shuttle spontaneously between the two in an AC mode, without the need for active switches to control the flow of charge.

[0022] refer to Figure 3 , is a schematic diagram of the thermodynamic cycle principle in this embodiment of the present invention. The enclosed area represents the energy collected by the material in the cycle. As can be seen from the figure, the pyroelectric thermodynamic cycle starts from point I at the beginning, and the corresponding dielectric elastomer capacitor also starts from point 1. When the dielectric elastomer capacitor is stretched and deformed under the action of external force, the formula , Q and Uare the charge and voltage of the dielectric elastomer capacitor, and the increase in its capacitance causes the voltage at both ends to drop, as shown in process 1 to 2 in the figure; at this time, the ferroelectric capacitor begins to be heated. Due to the pyroelectric effect of the ferroelectric capacitor, the capacitance decreases and the voltage increases when heated, as shown in process Ⅰ to Ⅱ; note that at this time, the internal diode of the self-bias circuit does not conduct because the voltage difference between the dielectric elastomer capacitor and the ferroelectric capacitor is not enough, so there is no charge transfer and the charge amount remains unchanged; as the dielectric elastomer capacitor continues to stretch to the maximum deformation, the capacitance increases to the maximum value, and the voltage at both ends continues to drop to the minimum. Since the voltage of the dielectric elastomer capacitor begins to be less than the voltage between the ferroelectric capacitor and the dielectric elastomer capacitor after point 2, the internal diode of the self-bias circuit is turned on and switched to a parallel state, and the charge is transferred from the ferroelectric capacitor to the dielectric elastomer capacitor, as shown in process 2 to 3; at this time, the temperature of the ferroelectric capacitor is kept unchanged, and the transfer of charge causes the two ends of the ferroelectric capacitor to The voltage decreases, as shown in process II to III; at point 3, the dielectric elastomer capacitor has been stretched to the maximum deformation and begins to shrink, the capacitance value decreases, and the voltage across it increases, as shown in process 3 to 4; at the same time, the ferroelectric capacitor begins to cool. Due to the pyroelectric effect of the ferroelectric capacitor, the capacitance value increases when it is cooled, and its voltage decreases, as shown in process III to IV; at this time, because the voltage across the dielectric elastomer is still smaller than the voltage of the ferroelectric capacitor, there is no charge transfer; as the dielectric elastomer capacitor continues to shrink to the minimum deformation, the capacitance value drops to the minimum, and the voltage across it continues to increase to the maximum. Since the voltage of the dielectric elastomer capacitor begins to be greater than the voltage of the ferroelectric capacitor after point 4, the internal diode of the self-bias circuit is turned on and switched to a series state, and the charge is transferred from the dielectric elastomer capacitor to the ferroelectric capacitor, as shown in process 4 to 1; at the same time, the temperature of the ferroelectric capacitor is kept unchanged, and the voltage across the ferroelectric capacitor increases due to the transfer of charge, as shown in process IV to I. So far, a thermodynamic QV cycle has been completed, and the area enclosed by the entire thermodynamic cycle is the energy collected by a thermodynamic cycle.

[0023] refer to Figure 4, which is a schematic diagram of the structure of the passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention, including a dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure and a cold-heat exchange structure, the cold-heat exchange structure provides a heat source 1 or a cold source 4 for the ferroelectric capacitor, the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure includes a dielectric elastomer capacitor 2 and a self-bias circuit 32, a plurality of ferroelectric capacitors 6 are arranged on the self-bias circuit 32, the heat source 1 and the cold source 4 provide heat or cold to the plurality of ferroelectric capacitors 6, and the charge pump circuit constructed by the ferroelectric capacitor can enable the system to achieve a constant charge and a high-voltage state during operation without the need for an external high-voltage power supply. Source, to achieve dynamic high-voltage changes in ferroelectric capacitors, and thus effectively construct a passive thermodynamic pyroelectric cycle; in AC mode, the charge can spontaneously shuttle through the dual-capacitor structure in AC mode as the capacitance changes, ensuring the effective circulation of the passive high-performance thermodynamic cycle and achieving efficient and continuous energy output, without the need for active switches to control charging and discharging, reducing dependence on external power sources; using the hot and cold exchange structure to achieve force field synchronization to control the temperature changes of the dielectric elastomer capacitor and the ferroelectric charge pumping circuit, thereby forming a synergistic effect, efficiently constructing a thermodynamic cycle to provide the system with a larger capacitance change and enhance the system's energy collection capabilities.

[0024] The passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention is described below with specific implementation methods.

[0025] Example 1 refer to Figure 5-6 , which is a structural diagram of a passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention. The passive high-performance pyroelectric thermodynamic cycle energy harvesting system is composed of a heat source 1, a dielectric elastomer capacitor 2, a self-bias voltage regulator circuit 3, a cold source 4, an external load 5 and a voltage regulator diode 7; the dielectric elastomer capacitor 2 is connected in series with the external load 5 and then connected in parallel on both sides of the self-bias voltage regulator circuit 3; the dielectric elastomer capacitor 2 includes a dielectric elastomer 21 and variable electrodes on both sides thereof; the self-bias voltage regulator circuit 3 includes a voltage regulator diode 31 and a self-bias circuit 32 arranged in parallel with the voltage regulator diode 31, and the self-bias circuit 32 is composed of a plurality of ferroelectric capacitors 6 and an internal diode 7, and the ferroelectric capacitor 6 is realized in a series-parallel mode by turning on and off the internal diode 7; the heat source 1 and the cold source 4 supply heat or cold to the plurality of ferroelectric capacitors 6 to realize the dynamic high-voltage change of the ferroelectric capacitor; the passive output of the electric energy of the pyroelectric thermodynamic cycle can be realized by using the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure.

[0026] In some embodiments, the self-bias circuit 32 may be in a multi-order form, preferably in a second-order form, and may include four ferroelectric capacitors 6 and five internal diodes 7. The series-parallel state of the ferroelectric capacitors is changed by turning on and off the internal diodes. The four ferroelectric capacitors are C1, C2, C3, and C4, and the five internal diodes are D1, D2, D3, D4, and D5. The five internal diodes are sequentially connected and connected in series with the voltage stabilizing device 31. The branch between D1 and D2 is connected with C1, the branch between D2 and D3 is connected with C2, the branch between D3 and D4 is connected with C3, the branch between D4 and D5 is connected with C4, and C1, C2, C3, and C4 are all connected in parallel with the voltage stabilizing device 31. The self-bias circuit can increase the system voltage, and the voltage stabilizing device 31 can release excess charge to prevent the dielectric elastomer film from being broken down.

[0027] Due to the characteristics of the charge pump circuit, dynamic high-voltage changes will spontaneously occur. Initially, when the dielectric elastomer is at its minimum contraction, diodes D2 and D4 are turned on, and the other three diodes are reversely cut off. At this time, capacitors C1 and C2 are connected in series, and capacitors C3 and C4 are connected in series. When the voltage of the dielectric elastomer capacitor decreases to the voltage of C1 as the deformation capacitance increases with the stretching, diodes D1 and D5 are turned on, and capacitors C1 and C4 charge the dielectric elastomer capacitor. When the dielectric elastomer capacitor continues to decrease with the stretching voltage, diode D3 is turned on, and capacitors C1 and C4 charge the dielectric elastomer capacitor together with C2 and C3 in series. When the dielectric elastomer is stretched to the maximum state and its voltage is the lowest, the voltage of the entire system is equal, all diodes are reversely cut off, and the capacitors do not work. As the dielectric elastomer contracts, the capacitance decreases and the voltage rises. When its voltage is greater than the sum of capacitors C1 and C2 and the sum of capacitors C3 and C4, the dielectric elastomer charges the circuit until it returns to the initial state and starts the next cycle.

[0028] The self-bias circuit 32 is a charge pump circuit such as Figure 6 As shown, the amount of charge in the system can be increased to offset the charge leakage effect of the capacitor device, wherein the on-off of the internal diode makes the internal capacitor work in a series or parallel mode, and the different series and parallel states make the overall capacitance value of the self-bias circuit different, so the ferroelectric capacitor can be used to construct a self-bias circuit, which is equivalent to a variable ferroelectric capacitor, and forms a dual-capacitor structure with the dielectric elastomer capacitor. When the system is working, due to the stretching and contraction of the dielectric elastomer capacitor, the "self-pumping" characteristic of the self-bias circuit switches between the series state and the parallel state, so that the positive and negative charges are separated, the overall charge of the system increases, and the voltage gradually increases and maintains the voltage required for the dual-capacitor structure to work, so that it does not need an external high-voltage source, thereby effectively constructing a passive pyroelectric thermodynamic cycle.

[0029] In some embodiments, the dielectric elastomer capacitor 2 is a stretchable elastomer capacitor, which is composed of a dielectric elastomer and variable electrodes on both sides. The dielectric elastomer is a stretchable elastic material selected from any one of silicone rubber, block copolymer, and thermoplastic bioplastics, and the variable electrodes on both sides are selected from any one of conductive silicone grease, silver nanowires, hydrogel, and ion conductors.

[0030] In some embodiments, the voltage stabilizing diode 31 releases excess charge in the system to stabilize the system.

[0031] In some embodiments, the external load 4 is a resistor, a light emitting diode, or a charging load consisting of a rectifier bridge and a capacitor.

[0032] In some embodiments, the ferroelectric capacitor 6 is made of a ferroelectric material having a pyroelectric effect. When the temperature changes, the ferroelectric capacitor value will change, the capacitance value will decrease when the temperature rises, and the capacitance value will increase when the temperature drops.

[0033] The structures of the heat source 1 and the cold source 4 are not limited, as long as they can provide heat or cold to a number of ferroelectric capacitors 6. A heat exchange pipeline structure can be used, and phase change materials and light-heat conversion materials can also be selected to achieve heat exchange.

[0034] The self-bias circuit in this passive high-performance pyroelectric thermodynamic cycle energy harvesting system is a charge pumping circuit with a "self-pumping" characteristic, which can increase the amount of charge in the system to offset the charge leakage effect of the capacitor device. The on-off of the internal diode makes the internal capacitor work in series or parallel mode. The different series and parallel states make the overall capacitance value of the self-bias circuit different. The self-bias circuit is constructed using the capacitor of ferroelectric material, which is equivalent to a variable ferroelectric capacitor, forming a dual capacitor structure with the dielectric elastomer capacitor.

[0035] refer to Figure 7 , which is a schematic diagram of the working principle of the self-biased circuit force field and thermal field in the passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided in this embodiment. When the dielectric elastomer capacitor is stretched, the dielectric elastomer capacitance value increases and its voltage decreases. According to the formula , Q and Uare respectively the charge and voltage of the dielectric elastomer capacitor. The voltage on both sides of the dielectric elastomer capacitor is smaller than the voltage of the ferroelectric capacitor. The self-bias circuit is switched to a parallel state and the ferroelectric capacitor is heated at the same time. Due to the pyroelectric effect of the ferroelectric capacitor, the capacitance value decreases and the voltage increases when heated, and the charge is transferred from the ferroelectric capacitor to the dielectric elastomer capacitor. When the dielectric elastomer capacitor shrinks, the dielectric elastomer capacitance value decreases and its voltage increases. The voltage on both sides of the dielectric elastomer capacitor is greater than the voltage of the ferroelectric capacitor. The self-bias circuit is switched to a series state and the ferroelectric capacitor is cooled at the same time. Due to the pyroelectric effect of the ferroelectric capacitor, the capacitance value increases and its voltage decreases when cooled, and the charge is transferred from the dielectric elastomer capacitor to the ferroelectric capacitor.

[0036] In order to better explain how the passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention realizes energy harvesting, the inventors conducted the following research: Conductive grease made of flexible electrode material is coated on the upper and lower surfaces of the dielectric elastomer polyacrylate film to form a dielectric elastomer capacitor. The dielectric elastomer material is 3M's VHB 490 with a thickness of 0.1 mm. The conductive grease is from Japan's Shin-Etsu. The electrode coating area is about 10 cm 2 A self-biased voltage regulator circuit is constructed using internal capacitors and internal diodes to ensure that the amount of charge output by the self-biased voltage regulator circuit to the dielectric elastomer capacitor is greater than the amount of charge input by the dielectric elastomer capacitor to the self-biased voltage regulator circuit. The sizes of the internal capacitors from top to bottom and from left to right are 40 nF, 20 nF, 40 nF, and 20 nF, respectively. A voltage regulator diode is introduced to stabilize the voltage of the energy harvesting system. This voltage regulator circuit can also use other voltage regulator circuits.

[0037] In this example, the ferroelectric capacitor in the self-bias circuit is fixed on the dielectric elastomer capacitor, which is purchased from Guangdong Fenghua High-Tech Co., Ltd. The deformation of the dielectric elastomer is used to make the ferroelectric capacitor contact the heat source or cold source. The ferroelectric capacitor is heated when stretched and cooled when contracted. The force field is consistent with the thermal field, and the thermodynamic cycle can be operated. The heat source refers to the facilities or equipment that emits heat when the waste heat is actually collected. The structure of the system can be changed according to different heat sources to adapt to different situations; the cold source refers to the equipment with relatively low temperature or other components that can dissipate heat from the system. Similarly, the structure of the system can also be changed accordingly to adapt to a variety of situations.

[0038] like Figure 8As shown in the figure, the output current curve and the ferroelectric capacitor temperature change curve before and after the passive high-performance pyroelectric thermodynamic cycle system is started, respectively. Through the influence of the periodic thermal field on the ferroelectric capacitor and the synchronous change of the dielectric elastomer capacitor, the capacitance value of the dual capacitor structure changes, resulting in an increase in the system output current from 2.18 μA to 10.05 μA, that is, the amount of transferred charge increases, and the energy that can be collected by the external load also increases. like Fig. 9 As shown in Figure 3, the energy density of the passive high-performance pyroelectric thermodynamic cycle energy harvesting system under the influence of periodic temperature is much higher than that of the system in the first three cycles without the effect of temperature. After the thermodynamic cycle is started, the energy density of the system increases from 5 mJ / g to 9.7 mJ / g and remains stable, which is consistent with Figure 8 The current variation law can also correspond.

[0039] In another specific implementation of the present invention, the temperature of the ferroelectric capacitor is controlled by using a fluid medium, such as Fig.10 As shown, the internal ferroelectric capacitor 6 is placed in the silicone pipe 9, and the cold and hot medium fluids flow out from the cold source 4 or the hot source 1 by using the natural drop or other external forces. The solenoid valve 8 controls the on-off and time. After passing through the ferroelectric capacitor, the fluid flows into the waste liquid container 10 for collection and recycling; The heat medium fluid is selected from any one of high temperature resistant inert insulating fluids such as synthetic hydrocarbons, fluorinated liquids, silicone oils and mineral oils.

[0040] In summary, the passive high-performance pyroelectric thermodynamic cycle energy harvesting system provided by the present invention utilizes the "self-pumping" characteristics of the self-bias circuit to realize the high-voltage passivity of the system; based on the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure, the power output of the pyroelectric thermodynamic cycle can be made passive. Based on the above two points, the "passivity" of the pyroelectric thermodynamic cycle energy harvesting can be realized, that is, it can be well applied to energy storage equipment without the need for an external high-voltage power supply and an active control module.

[0041] For matters not mentioned above, the prior art applies.

[0042] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system, characterized in that: The invention comprises a dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure and a heat exchange structure, wherein the heat exchange structure provides a heat source (1) or a cold source (4) for the ferroelectric capacitor, the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure comprises a dielectric elastomer capacitor (2) and a self-bias circuit (32), a plurality of ferroelectric capacitors (6) are arranged on the self-bias circuit (32), the heat source (1) and the cold source (4) provide heat or cold to the plurality of ferroelectric capacitors (6), and the self-pumping electrical characteristics of the self-bias circuit (32) realize dynamic high-voltage changes of the ferroelectric capacitor; the dielectric elastomer capacitor-ferroelectric capacitor dual capacitor structure can realize the passivity of the electric energy output of the pyroelectric thermodynamic cycle.

2. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 1, characterized in that: A voltage stabilizing diode (31) is arranged in parallel on the self-bias circuit (32); the self-bias circuit (32) and the voltage stabilizing diode (31) constitute a self-bias voltage stabilizing circuit (3); the self-bias circuit (32) is composed of a plurality of ferroelectric capacitors (6) and an internal diode (7); the ferroelectric capacitors (6) are in a series-parallel mode by turning on and off the internal diode (7).

3. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 2, characterized in that: The self-bias circuit (32) comprises four ferroelectric capacitors (6) and five internal diodes (7), and the series-parallel state of the ferroelectric capacitors is changed by turning on and off the internal diodes. The four ferroelectric capacitors are C1, C2, C3 and C4, and the five internal diodes are D1, D2, D3, D4 and D5.

4. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 3, characterized in that: The five internal diodes (7) are connected in sequence and connected in series with the voltage stabilizing diode (31); C1 is connected to the branch between D1 and D2; C2 is connected to the branch between D2 and D3; C3 is connected to the branch between D3 and D4; and C4 is connected to the branch between D4 and D5; C1, C2, C3 and C4 are all connected in parallel with the voltage stabilizing diode (31).

5. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system according to any one of claims 1 to 4, characterized in that: The dielectric elastomer capacitor (2) is connected in series with an external load (5) and then connected in parallel to both sides of the self-biased voltage stabilization circuit (3); the dielectric elastomer capacitor (2) comprises a dielectric elastomer (21) and variable electrodes (22) on both sides thereof.

6. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 5, characterized in that: The external load (5) is a resistor, a light emitting diode, or a charging load composed of a rectifier bridge and a capacitor.

7. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 5, characterized in that: The dielectric elastomer capacitor (2) is a stretchable elastomer capacitor, which is composed of a dielectric elastomer and variable electrodes on both sides. The dielectric elastomer is a stretchable elastic material selected from any one of silicone rubber, block copolymer, and thermoplastic bioplastics. The variable electrodes on both sides are selected from any one of conductive silicone grease, silver nanowires, hydrogel, and ion conductors.

8. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 2, characterized in that: The voltage stabilizing diode (31) releases excess charge in the system to achieve the purpose of stabilizing the system.

9. A passive high-performance pyroelectric thermodynamic cycle energy harvesting system as claimed in claim 1, characterized in that: The ferroelectric capacitor (6) is made of a ferroelectric material having a pyroelectric effect. When the temperature changes, the ferroelectric capacitor value will change, with the temperature increasing and the capacitance value decreasing, while the temperature decreasing and the capacitance value increasing.

10. An energy storage device, characterized in that: A passive high-performance pyroelectric thermodynamic cycle energy harvesting system comprising any one of claims 1 to 9.

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