A Radioactive Isotope Nuclear Battery Film and Its Preparation Method

Abstract

The present invention relates to a thin film for a radioisotope nuclear battery and a preparation method thereof. The thin film includes: a substrate; a planar thermoelectric conversion unit disposed on the substrate, which includes an inner electrode, an outer electrode disposed on the substrate, and at least one group of P-type thermoelectric material layers and N-type thermoelectric material layers. Both ends of the P-type thermoelectric material layer and the N-type thermoelectric material layer are respectively connected to the inner electrode and the outer electrode, and the inner electrode and the outer electrode are arranged in segments; a nuclear power conversion unit: including a high-resistance substrate disposed on the inner electrode and a nuclear power conversion material located on the high-resistance substrate; a radioisotope layer located on the nuclear power conversion material. The thin film of the radioisotope nuclear battery of the present invention simultaneously utilizes the photovoltaic effect and the thermoelectric conversion effect, which is beneficial to improving the utilization rate of isotope radiation energy, and has a long lateral dimension, can establish a large temperature difference, and improve the output performance of the thermoelectric conversion unit, etc.

Description

Technical Field

[0001] The present invention belongs to the technical fields of semiconductor devices and nuclear science and technology, and relates to a radioactive isotope nuclear battery thin film and a preparation method thereof. Background Art

[0002] A radioactive isotope battery (abbreviated as nuclear battery) is a battery that uses a transducer material to convert the energy of rays released during the decay of radioactive isotopes into electrical energy. Compared with traditional batteries, nuclear batteries have the advantages of long life, high energy density, strong environmental adaptability, and good working stability. Therefore, nuclear batteries have high potential application value in the fields of aerospace, deep sea and polar exploration, microelectromechanical systems, and modern medicine.

[0003] Nuclear batteries can be classified according to different radioactive isotope sources. Currently, the relatively mature ones are α nuclear batteries and β nuclear batteries. The energy conversion mechanisms in nuclear batteries can be divided into the thermoelectric effect, the thermophotovoltaic effect, and the radiovoltaic effect. The thermoelectric effect uses the interaction between ray particles and a dielectric material to generate heat, and then uses a thermoelectric device to convert the thermal energy into electrical energy. The thermo (radiation) photovoltaic effect uses the material to absorb the decay energy of ray particles and convert it into light energy, and then uses a photovoltaic device to convert the thermal energy into electrical energy. The radiovoltaic effect is a process in which ray particles interact with the material of a semiconductor device to generate electron-hole pairs, and under the action of a built-in electric field, they migrate to both ends of the electrodes, and electrical energy conversion is achieved through a closed loop.

[0004] With the development of isotope source preparation technology and semiconductor processing technology, researchers' attention has shifted to various new materials, new semiconductor transducer units, and new nuclear battery structure designs. However, there is still a lack of relevant research on the comprehensive utilization of nuclear battery energy and the simple and rapid large-area preparation. Summary of the Invention

[0005] The purpose of the present invention is to provide a radioactive isotope nuclear battery thin film and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention provides a radioactive isotope nuclear battery thin film, including:

[0008] A substrate;

[0009] A planar thermoelectric transducer unit disposed on the substrate: It includes an inner electrode, an outer electrode disposed on the substrate, and at least one group of P-type thermoelectric material layers and N-type thermoelectric material layers. Both ends of the P-type thermoelectric material layer and the N-type thermoelectric material layer are respectively connected to the inner electrode and the outer electrode. The inner electrode and the outer electrode are arranged in segments and connect all the P-type thermoelectric material layers and N-type thermoelectric material layers in series;

[0010] Nuclear power conversion unit: including a high-resistance substrate disposed on the inner electrode and a nuclear power conversion material located on the high-resistance substrate;

[0011] A radioactive isotope layer located on the nuclear power conversion material.

[0012] Furthermore, the planar thermoelectric conversion unit is arranged in a surrounding type or a symmetric type,

[0013] When the planar thermoelectric conversion unit is arranged in a surrounding type, the segmented inner electrodes and outer electrodes respectively enclose an inner circle and an outer circle at intervals, and the P-type thermoelectric material layer and the N-type thermoelectric material layer are disposed between the inner electrodes and the outer electrodes;

[0014] When the planar thermoelectric conversion unit is arranged in a symmetric type, the inner electrodes and the outer electrodes are respectively arranged at intervals and form two symmetric rows, the P-type thermoelectric material layer and the N-type thermoelectric material layer are also symmetrically arranged between the inner electrodes and the outer electrodes, and the outer electrodes at the same end in the two rows of outer electrodes are also connected.

[0015] Furthermore, the nuclear power conversion unit is circular or rectangular.

[0016] Furthermore, the number of series connections in the planar thermoelectric conversion unit is n, n≥1, that is, the number of sets of the P-type thermoelectric material layer and the N-type thermoelectric material layer is n.

[0017] Furthermore, the nuclear power conversion material is a PN junction, a PIN junction or a Schottky diode.

[0018] Furthermore, the widths of the P-type thermoelectric material layer and the N-type thermoelectric material layer are 1 to 100 mm, the lengths are 1 to 100 mm, and the thicknesses are 1 to 1000 μm.

[0019] Furthermore, the widths of the inner electrodes and the outer electrodes are 1 to 100 mm, the lengths are 1 to 100 mm, and the thicknesses are 1 to 1000 μm.

[0020] Furthermore, the radioactive source of the radioactive isotope layer is nickel-63, krypton-85, strontium-90 or promethium-147, and its thickness is 1 to 50 μm.

[0021] Furthermore, the area of the radioactive isotope layer is less than or equal to the area of the nuclear power conversion unit.

[0022] Furthermore, the nuclear power conversion unit and the planar thermoelectric conversion unit are also connected by an internal circuit to serially export the generated electric energy.

[0023] Further, the radioactive isotope nuclear battery thin films are also connected in series to form a nuclear battery pack for supplying power to an electrical appliance, where the number of radioactive isotope nuclear battery thin films connected in series is m, and m is an integer not less than 1.

[0024] Furthermore, when different radioactive isotope nuclear battery thin films are connected in series to form a nuclear battery pack, a radioactive isotope layer or a substrate is shared between two adjacent radioactive isotope nuclear battery thin films.

[0025] Further, the radioactive isotope nuclear battery thin films are also covered with an isolation and protection layer, which can be specifically arranged between the substrates of two radioactive isotope nuclear battery thin films connected in series.

[0026] Further, the substrate can be one or more of textiles, paper, coatings, plastics, polymers, ceramics, metals, silicon wafers, and glass.

[0027] The second technical solution of the present invention provides a method for preparing a radioactive isotope nuclear battery thin film, which is characterized by including the following steps:

[0028] (1) Dispose segmented inner electrodes and outer electrodes on the substrate;

[0029] (2) Dispose a P-type thermoelectric material layer and an N-type thermoelectric material layer between the inner electrode and the outer electrode, so that the P-type thermoelectric material layer and the N-type thermoelectric material layer are connected in series through the inner electrode and the outer electrode to obtain a planar thermoelectric conversion unit;

[0030] (3) After drying the planar thermoelectric conversion unit, attach a high-resistance substrate above the inner electrode;

[0031] (4) Deposit a nuclear power conversion unit and a radioactive isotope layer on the high-resistance substrate in sequence;

[0032] (5) Connect and export the electric energy generated by the planar thermoelectric conversion unit and the nuclear power conversion unit in series through wires.

[0033] The present invention provides a device for efficiently utilizing the ray energy released during the decay of radioactive isotopes and a method for preparing the same. When a radioactive isotope decays, the released particles bombard a nuclear power conversion material, generating a large number of electron-hole pairs inside the material. These electron-hole pairs move directionally under the action of the built-in electric field to form an electric current. During the decay of the radioactive isotope and the process of particle bombardment of the nuclear power conversion material, a large amount of heat is released, and this heat can drive the directional movement of electron-hole pairs in the thermoelectric conversion materials (N-type thermoelectric material and P-type thermoelectric material), thereby generating an electric current. By comprehensively utilizing these two ways of generating an electric current, the overall output performance of the device can be improved. In the present invention, the radioactive isotope layer and the nuclear power conversion material are distributed in a planar manner up and down, which can increase the contact area and improve the utilization rate of the isotope decay energy. The nuclear power conversion material and the thermoelectric conversion material are distributed in a planar manner up and down, which can increase the contact area and improve the utilization rate of low-quality heat energy. The high-resistance substrate is used to isolate the nuclear power conversion material and the inner electrode, preventing the electrons in the inner electrode material from neutralizing the holes in the nuclear power conversion material. In addition, the high-resistance substrate can also make the heat generated by the nuclear power conversion material more evenly introduced into the thermoelectric conversion material. The thermoelectric conversion materials in the present invention are arranged in a planar manner on the substrate, which can increase the lengths of the N-type thermoelectric material and the P-type thermoelectric material, establish a larger temperature difference, and improve the comprehensive utilization efficiency of heat energy.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] ① This radioactive isotope nuclear battery thin film can simultaneously utilize the radiovoltaic effect and the thermoelectric conversion effect, improving the utilization efficiency of nuclear energy and extending the service life of the radioactive isotope nuclear battery.

[0036] ② This planar thermoelectric conversion unit has a relatively long lateral dimension, can establish a large temperature difference, and improve the output performance of the thermoelectric conversion unit.

[0037] ③ This radioactive isotope nuclear battery thin film has less dependence on the substrate, can be prepared on a flexible or rigid substrate, and has a broad application scenario.

[0038] ④ This radioactive isotope nuclear battery thin film is convenient for large-area planar preparation, and has a small thickness and small volume, which is convenient for assembly and implementation. Description of the Drawings

[0039] Figure 1 It is a top view schematic diagram of the annular radioactive isotope nuclear battery thin film of the present invention;

[0040] Figure 2 It is a cross-sectional schematic diagram of the annular radioactive isotope nuclear battery thin film of the present invention;

[0041] Figure 3Top view schematic diagram of the symmetric radioisotope nuclear battery thin film of the present invention;

[0042] Figure 4 Cross-sectional schematic diagram of the symmetric radioisotope nuclear battery thin film of the present invention;

[0043] Figure 5 Double-layer assembly schematic diagram of the radioisotope nuclear battery thin film of the present invention;

[0044] Figure 6 Double-layer isolation type assembly schematic diagram of the radioisotope nuclear battery thin film of the present invention;

[0045] Figure 7 Multi-layer isolation type assembly schematic diagram of the radioisotope nuclear battery thin film of the present invention;

[0046] Explanation of the marks in the figure:

[0047] 1. Outer electrode; 2. N-type thermoelectric material layer; 3. P-type thermoelectric material layer; 4. Inner electrode; 5. Substrate; 6. Radioisotope layer; 7. Nuclear power conversion material; 8. High-resistance substrate; 9. Isolation and protection layer. Detailed implementation manners

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. It should be noted that the present invention can be implemented in different forms and should be adjusted according to the actual situation. The proposed embodiments are intended to achieve a full and complete disclosure, so that those skilled in the art can fully understand the scope of the present invention and should not be construed as being limited by the proposed embodiments.

[0049] In the following reference drawings, for the convenience of description, the sizes of different layers and regions are enlarged or reduced. Therefore, the sizes shown do not necessarily represent the actual sizes and do not reflect the proportional relationship of the sizes. The reference drawings are schematic diagrams of the idealized embodiments of the present invention. The embodiments shown in the present invention should not be considered limited to the specific shapes of the regions shown in the drawings, but include the obtained shapes, such as deviations caused by manufacturing. In the embodiments of the present invention, each part is represented by a rectangle, and the representation in the drawings is schematic, but this should not be considered as limiting the scope of the present invention.

[0050] In the following embodiments or implementation manners, if there is no special description of the raw materials or processing techniques, it means that they are all conventional commercially available raw materials or conventional processing techniques in the art.

[0051] The present invention provides a radioisotope nuclear battery thin film, and its structure is shown in Figures 1 to 7 as follows, including:

[0052] Substrate;

[0053] Planar thermoelectric conversion unit disposed on the substrate: It includes an inner electrode, an outer electrode disposed on the substrate, and at least one set of P-type thermoelectric material layers and N-type thermoelectric material layers. Both ends of the P-type thermoelectric material layers and N-type thermoelectric material layers are respectively connected to the inner electrode and the outer electrode. The inner electrode and the outer electrode are arranged in segments, and all the P-type thermoelectric material layers and N-type thermoelectric material layers are connected in series;

[0054] Nuclear power conversion unit: It includes a high-resistance substrate disposed on the inner electrode, and a nuclear power conversion material located on the high-resistance substrate;

[0055] A radioactive isotope layer located on the nuclear power conversion material.

[0056] In some specific embodiments, the planar thermoelectric conversion unit is arranged in a circular arrangement or a symmetric arrangement.

[0057] Please refer to Figures 1 to 2 As shown, when the planar thermoelectric conversion unit is arranged in a circular arrangement, the segmented inner electrode and outer electrode respectively enclose an inner circle and an outer circle at intervals, and the P-type thermoelectric material layers and N-type thermoelectric material layers are disposed between the inner electrode and the outer electrode;

[0058] Please refer to Figures 3 to 4 As shown, when the planar thermoelectric conversion unit is arranged in a symmetric arrangement, the inner electrode and the outer electrode are respectively arranged at intervals and form two symmetric rows, and the P-type thermoelectric material layers and N-type thermoelectric material layers are also symmetrically arranged between the inner electrode and the outer electrode. The outer electrodes at the same end in the two rows of outer electrodes are also directly connected.

[0059] In a more specific embodiment, the nuclear power conversion unit is circular or rectangular.

[0060] In some specific embodiments, the number of series connections in the planar thermoelectric conversion unit is n, n≥1, that is, the number of P-type thermoelectric material layers and N-type thermoelectric material layers is n.

[0061] In some specific embodiments, the nuclear power conversion material is a PN junction, a PIN junction or a Schottky diode.

[0062] In some specific embodiments, the width of the P-type thermoelectric material layers and N-type thermoelectric material layers is 1 - 100 mm, the length is 1 - 100 mm, and the thickness is 1 - 1000 μm.

[0063] In some specific embodiments, the width of the inner electrode and the outer electrode is 1 - 100 mm, the length is 1 - 100 mm, and the thickness is 1 - 1000 μm.

[0064] In some specific embodiments, the radioactive source of the radioactive isotope layer is nickel-63, krypton-85, strontium-90 or promethium-147, and its thickness is 1 to 50 μm.

[0065] In some specific embodiments, the area of the radioactive isotope layer is less than or equal to the area of the nuclear power conversion unit.

[0066] In some specific embodiments, the nuclear power conversion unit and the planar thermoelectric conversion unit are also connected through an internal circuit to serially export the generated electric energy.

[0067] In some specific embodiments, please refer to Figures 5 to 7 As shown, the radioactive isotope nuclear battery thin film is also formed into a nuclear battery pack in series to supply energy to the electrical appliance. Among them, the number of series-connected radioactive isotope nuclear battery thin films is m, and m is an integer not less than 1.

[0068] In a more specific embodiment, when different radioactive isotope nuclear battery thin films are connected in series to form a nuclear battery pack, a radioactive isotope layer or a substrate is shared between two adjacent radioactive isotope nuclear battery thin films.

[0069] In some specific embodiments, the radioactive isotope nuclear battery thin film is also covered with an isolation protection layer, which can be specifically arranged between the substrates of two series-connected radioactive isotope nuclear battery thin films.

[0070] Each of the above embodiments can be implemented alone, or can be combined in any pair or more combinations.

[0071] The above embodiments will be described in more detail below in conjunction with specific examples. The preparation methods of "Bi2Te3 thermoelectric ink" and "Sb2Te3 thermoelectric ink" used in the following examples refer to the reference Energy Environ. Sci., 2014, 7, 1959 (DOI: 10.1039 / c4ee00242c).

[0072] Example 1:

[0073] Combined with the above embodiments and Figures 1 to 2 , in this example, a radioactive isotope nuclear battery thin film is prepared on A4 paper by screen printing technology, which specifically includes the following steps:

[0074] Step 1: Select A4 paper as the substrate, and use silver paste as the conductive ink to draw the inner electrode and the outer electrode on the A4 paper by screen printing technology. The electrodes are distributed in a surrounding manner. The width of the electrode is 5 mm, the length is 10 mm, and the thickness is 200 μm.

[0075] Step 2: Draw Bi2Te3 thermoelectric ink and Sb2Te3 thermoelectric ink between the inner electrode and the outer electrode through screen printing technology to form a surrounding N-type thermoelectric material layer and P-type thermoelectric material layer, and form a series structure with a series number of 5. The width of the thermoelectric ink is 5 mm, the length is 15 mm, and the thickness is 200 μm.

[0076] Step 3: Air-dry the above planar thermoelectric conversion unit at room temperature.

[0077] Step 4: Attach a 200-μm gallium arsenide substrate as a high-resistance substrate above the inner electrode, and the area of the gallium arsenide substrate is less than or equal to the area of the circle enclosed by the inner electrode.

[0078] Step 5: Deposit a 10-μm silicon carbide PN structure on the gallium arsenide substrate as a nuclear power conversion material.

[0079] Step 6: Attach a 2-μm-thick nickel-63 above the nuclear power conversion material as a radioactive isotope layer, and the area of the radioactive isotope layer is equal to the area of the nuclear power conversion unit.

[0080] Step 7: Connect the electrical energy generated by the planar thermoelectric conversion unit and the nuclear power conversion unit in series through wires and lead it out.

[0081] Example 2:

[0082] Compared with Example 1, most of them are the same, except that in this example, the N-type thermoelectric material layer and the P-type thermoelectric material layer are symmetrically distributed ( Figures 3 to 4 ).

[0083] Example 3:

[0084] Compared with Example 1, most of them are the same, except that in this example, the nuclear power conversion material is a silicon carbide Schottky junction.

[0085] Example 4:

[0086] Compared with Example 1, most of them are the same, except that in this example, the series number of the planar thermoelectric conversion unit is 50.

[0087] Example 5:

[0088] Compared with Example 1, most of them are the same, except that in this example, the structure prepared in Step 5 and the structure prepared in Step 6 are attached together to form a whole, please refer to Figure 5 as shown.

[0089] Example 6:

[0090] Compared with Example 5, most of them are the same, except that in this example, the radioactive isotope nuclear battery film is encapsulated with an isolation protection layer, please refer toFigure 6 as shown

[0091] Example 7:

[0092] Compared with Example 6, most of them are the same. Except in this example, 8 radioisotope nuclear battery films are assembled into a whole. Please refer to Figure 7 as shown

[0093] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A thin film of a radioisotope nuclear battery, characterized in that, Comprising: A substrate; A planar thermoelectric conversion unit disposed on the substrate: It includes an inner electrode, an outer electrode disposed on the substrate, and at least one group of P-type thermoelectric material layers and N-type thermoelectric material layers. Both ends of the P-type thermoelectric material layers and N-type thermoelectric material layers are respectively connected to the inner electrode and the outer electrode. The inner electrode and the outer electrode are arranged in segments and connect all the P-type thermoelectric material layers and N-type thermoelectric material layers in series; A nuclear power conversion unit: It includes a high-resistance substrate disposed on the inner electrode and a nuclear power conversion material located on the high-resistance substrate; A radioactive isotope layer located on the nuclear power conversion material; The planar thermoelectric conversion unit is arranged in a surrounding type or a symmetric type, When the planar thermoelectric conversion unit is arranged in a surrounding type, the segmented inner electrode and outer electrode respectively enclose an inner circle and an outer circle at intervals, and the P-type thermoelectric material layers and N-type thermoelectric material layers are placed between the inner electrode and the outer electrode; When the planar thermoelectric conversion unit is arranged in a symmetric type, the inner electrode and the outer electrode are respectively arranged at intervals and form two symmetric rows. The P-type thermoelectric material layers and N-type thermoelectric material layers are also symmetrically arranged between the inner electrode and the outer electrode. The outer electrodes at the same end in the two rows of outer electrodes are also connected; The nuclear power conversion material is a PN junction, a PIN junction or a Schottky diode; The area of the radioactive isotope layer is equal to the area of the nuclear power conversion unit; The width of the P-type thermoelectric material layers and N-type thermoelectric material layers is 1 - 100 mm, the length is 1 - 100 mm, and the thickness is 1 - 1000 μm; The width of the inner electrode and the outer electrode is 1 - 100 mm, the length is 1 - 100 mm, and the thickness is 1 - 1000 μm; The radioactive source of the radioactive isotope layer is nickel-63, krypton-85, strontium-90 or promethium-147, and its thickness is 1 - 50 μm.

2. The thin film of a radioisotope nuclear battery according to claim 1, wherein The nuclear power conversion unit and the planar thermoelectric conversion unit are also connected to each other through an internal circuit to serially export the generated electric energy.

3. A radioactive isotope nuclear battery thin film according to claim 1, characterized in that, The radioactive isotope nuclear battery thin films are also connected in series to form a nuclear battery pack to supply energy to an electrical appliance. Among them, the number of radioactive isotope nuclear battery thin films connected in series is m, and m is an integer not less than 1.

4. A radioactive isotope nuclear battery thin film according to claim 3, characterized in that When different radioactive isotope nuclear battery thin films are connected in series to form a nuclear battery pack, a radioactive isotope layer or a substrate is shared between two adjacent radioactive isotope nuclear battery thin films.

5. A radioactive isotope nuclear battery thin film according to claim 4, characterized in that, An isolation and protection layer is also provided between the substrates of two adjacent radioactive isotope nuclear battery thin films.

6. The preparation method of a thin film of a radioisotope nuclear battery according to any one of claims 1-5, characterized in that, Including the following steps: (1) Arrange a segmented inner electrode and outer electrode on the substrate; (2) Arrange P-type thermoelectric material layers and N-type thermoelectric material layers between the inner electrode and the outer electrode so that the P-type thermoelectric material layers and N-type thermoelectric material layers are connected in series through the inner electrode and the outer electrode to obtain a planar thermoelectric conversion unit; (3) After drying the planar thermoelectric conversion unit, attach a high-resistance substrate above the inner electrode; (4) Deposit a nuclear power conversion unit and a radioactive isotope layer on the high-resistance substrate in sequence; (5) Serially export the electric energy generated by the planar thermoelectric conversion unit and the nuclear power conversion unit through a wire.

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