Structural design method of isotope battery and isotope battery

Abstract

The embodiment of the invention provides a structural design method of an isotope battery and the isotope battery, and the structural design method of the isotope battery comprises the steps that a geometric model of the isotope battery is established, and a thermoelectric conversion device of the isotope battery comprises multiple pairs of thermoelectric unicouples which are connected in series; each pair of thermoelectric unicouples comprises two thermoelectric unicouples which have different polarities and are connected in series; determining output heat energy of a source core of the isotope battery; variable parameters of the thermoelectric unicouple are set, the maximum output efficiency of the isotope battery is obtained based on the variable parameters, and the variable parameters comprise at least one of the height variable, the cross sectional area variable and the logarithmic variable of the thermoelectric unicouple. According to the structural design method of the isotope battery provided by the embodiment of the invention, simulation research is carried out on the structural design of the isotope battery through COMSOL software, and a reasonable theoretical basis is provided for high-integration and high-output-efficiency design of the isotope battery.

Description

Technical Field

[0001] The present application relates to the technical field of thermoelectric power sources, and in particular to a structural design method of an isotope battery and an isotope battery. Background Art

[0002] Radioisotope thermoelectric generator (RTG), also known as radioisotope thermoelectric battery, isotope battery for short, in which thermoelectric conversion device is an important component of isotope battery. Thermoelectric conversion device can convert the heat energy generated by the decay of radioisotopes into electrical energy by using the Seebeck effect.

[0003] Among the related technologies, isotope batteries have the advantages of long life, good environmental adaptability, and high reliability, so they have broad application prospects in exploration environments such as space, deep sea, and polar regions. For microelectronic devices, the required battery power is very small, often only a few milliwatts, but the volume and mass of the battery need to be as small as possible to meet the needs of highly integrated electronic devices. Summary of the invention

[0004] In view of this, the embodiments of the present application hope to provide a structural design method of an isotope battery and an isotope battery to improve the integration of the isotope battery and the battery output efficiency.

[0005] To achieve the above-mentioned purpose, one aspect of an embodiment of the present application provides a structural design method for an isotope battery, the structural design method comprising:

[0006] Establishing a geometric model of the isotope battery, wherein the thermoelectric conversion device of the isotope battery includes a plurality of pairs of thermoelectric monocouples connected in series, and each pair of the thermoelectric monocouples includes two thermoelectric monocouples with different polarities and connected in series;

[0007] determining the output heat energy of the source core of the isotope battery;

[0008] The variable parameters of the thermocouple are set, and based on the variable parameters, the maximum output efficiency of the isotope battery is obtained, wherein the variable parameters include at least one of a height variable, a cross-sectional area variable, and a logarithmic variable of the thermocouple.

[0009] In some embodiments, obtaining the maximum output efficiency of the isotope battery includes:

[0010] The maximum output power of the isotope battery is obtained, wherein the maximum output power of the isotope battery is the product of the maximum output efficiency of the isotope battery and the output thermal energy of the source core.

[0011] In some embodiments, obtaining the maximum output efficiency of the isotope battery includes:

[0012] Obtaining a thermal efficiency distribution diagram of the isotope battery;

[0013] Obtaining a thermoelectric efficiency distribution diagram of the isotope battery;

[0014] Among them, the thermal efficiency of the isotope battery is the ratio of the thermal energy actually obtained by all the thermoelectric monocouples to the output thermal energy of the source core, and the thermoelectric efficiency of the isotope battery is the ratio of the electric energy actually converted by the thermoelectric conversion device to the thermal energy actually obtained by the thermoelectric conversion device; the electric energy actually converted by the thermoelectric conversion device is the output power of the isotope battery, and the output efficiency of the isotope battery is the product of the thermal efficiency of the isotope battery and the thermoelectric efficiency of the isotope battery.

[0015] In some embodiments, the setting of the variable parameters of the thermocouple includes:

[0016] The height value and logarithmic value of the thermocouple are arbitrarily determined, and the cross-sectional area variable of the thermocouple is set.

[0017] In some embodiments, the setting of the variable parameters of the thermocouple includes:

[0018] The logarithmic value and cross-sectional area value of the thermocouple are arbitrarily determined to set the height variable of the thermocouple.

[0019] In some embodiments, the setting of the variable parameters of the thermocouple includes:

[0020] The height value and cross-sectional area value of the thermocouple are arbitrarily determined, and the logarithmic variable of the thermocouple is set.

[0021] In some embodiments, the setting of the variable parameters of the thermocouple includes:

[0022] Obtaining a cross-sectional area value and a height value of the isotope battery at any determined logarithm and at maximum output power;

[0023] Set the logarithmic variable of the thermocouple.

[0024] In some embodiments, obtaining the cross-sectional area value and height value of the isotope battery at the maximum output power includes:

[0025] Taking any determined logarithmic value of the thermoelectric monocouple, determining a plurality of different cross-sectional area values, setting a height variable of the thermoelectric monocouple, and obtaining a power output distribution diagram of the isotope battery at each cross-sectional area value;

[0026] A plurality of power output distribution diagrams obtained under a plurality of different cross-sectional area values ​​are fitted to obtain the height value and the cross-sectional area value corresponding to the maximum output power.

[0027] In some embodiments, the multiple different cross-sectional area values ​​vary linearly.

[0028] In some embodiments, obtaining the maximum output efficiency of the isotope battery includes:

[0029] Based on the logarithmic variable of the thermoelectric monocouple, obtaining an output power distribution diagram of the isotope battery;

[0030] Obtain the maximum output power of the isotope battery and its logarithmic value at the maximum output power;

[0031] The maximum output efficiency of the isotope battery is determined.

[0032] In some embodiments, after obtaining the maximum output efficiency of the isotope battery, the structural design method further includes:

[0033] Based on the variable parameters corresponding to the maximum output efficiency, determining the corresponding geometric model of the isotope battery;

[0034] Obtaining a temperature distribution diagram of each structure of the isotope battery;

[0035] Based on the temperature distribution diagram, it is determined whether the isotope battery is within a preset operating temperature range.

[0036] Another aspect of the embodiment of the present application provides an isotope battery, which adopts any of the above structural design methods, including:

[0037] The housing assembly comprises an outer housing and an end cover, wherein the end cover is arranged at one end of the outer housing along the axial direction to define a closed accommodation space;

[0038] A source core, disposed in the accommodation space, for dissipating heat energy;

[0039] A thermoelectric conversion device is disposed in the accommodation space, and is used to convert the thermal energy of the source core into electrical energy;

[0040] The cross-sectional area of ​​the thermocouple is 1 mm 2 ~4mm 2 ;

[0041] And / or, the height of the thermocouple is 30 mm to 50 mm;

[0042] And / or, the number of pairs of the thermoelectric monocouples is 40-60.

[0043] The structural design method of the isotope battery provided in the embodiment of the present application can provide a theoretical basis for the preparation of the actual isotope battery by simulating the structural design of the isotope battery in COMSOL software, setting the output heat energy of the source core to be determined, and setting at least one of the height variable, the cross-sectional area variable, and the logarithmic variable of the thermoelectric monopole as a variable parameter, so that the environment in which the isotope battery is located is close to the environment in which the actual application is located, and by setting the variable parameters, the variation law of the output efficiency of the isotope battery is obtained, thereby obtaining the maximum output efficiency of the isotope battery, so as to facilitate the design of various parameters of the thermoelectric monopole corresponding to the maximum output efficiency, so that the isotope battery actually used is in the best working state, and under the condition of the determined output heat energy, the output power of the isotope battery can also be in the best state, thereby improving the integration of the isotope battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of a structural design method for an isotope battery provided in an embodiment of the present application;

[0045] Figure 2 A schematic flow chart of a structural design method for an isotope battery provided in another embodiment of the present application;

[0046] Figure 3 A first line graph in an embodiment of the present application;

[0047] Figure 4 The thermal efficiency distribution diagram and thermoelectric efficiency distribution diagram of the isotope battery in one embodiment of the present application;

[0048] Figure 5 A second line graph in one embodiment of the present application;

[0049] Figure 6 This is a temperature distribution diagram of the various parts of the isotope battery structure in one embodiment of the present application;

[0050] Figure 7 A temperature distribution diagram of a thermoelectric conversion component of an isotope battery in one embodiment of the present application;

[0051] Figure 8 This is a schematic diagram of the structure of an isotope battery in one embodiment of the present application;

[0052] Fig. 9 An exploded schematic diagram of a thermoelectric conversion component and a heat source component of an isotope battery in one embodiment of the present application;

[0053] Fig.10 Schematic diagram of the structure of a thermoelectric conversion component and a heat source component in one embodiment of the present application.

[0054] Description of Reference Numerals

[0055] 10. Isotope battery; 11. Thermoelectric conversion assembly; 111. Thermoelectric conversion device; 1111. Electrode sheet; 1112. Thermoelectric monocouple; 112. Substrate; 12. Heat source assembly; 121. Source core; 122. Pressure head; 123. Tungsten lining; 124. Sealing cladding; 125. Structural cladding; 13. Structural functional assembly; 131. Collector; 132. Heat-conducting tube; 133. Insulation layer; 134. Shielding layer; 135. Shell assembly; 1351. Shell; 1352. End cover. DETAILED DESCRIPTION

[0056] The following is a further detailed description of the implementation of the present application in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application.

[0057] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0058] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] Radioisotope thermoelectric generator (RTG), also known as radioisotope thermoelectric battery, isotope battery for short, in which thermoelectric conversion device is an important component of isotope battery. Thermoelectric conversion device can convert the heat energy generated by the decay of radioisotopes into electrical energy by using the Seebeck effect.

[0061] Among the related technologies, isotope batteries have the advantages of long life, good environmental adaptability, and high reliability, so they have broad application prospects in exploration environments such as space, deep sea, and polar regions. For microelectronic devices, the required battery power is very small, often only a few milliwatts, but the volume and mass of the battery need to be as small as possible to meet the needs of highly integrated electronic devices.

[0062] Based on the above situation, the first aspect of the embodiment of the present application provides a structural design method of an isotope battery 10, please refer to Figure 1 as well as Figures 8 to 10 The structural design methods include:

[0063] S100: establishing a geometric model of an isotope battery, wherein a thermoelectric conversion device of the isotope battery includes a plurality of pairs of thermoelectric monocouples connected in series, and each pair of thermoelectric monocouples includes two thermoelectric monocouples with different polarities and connected in series;

[0064] S200: determining the output heat energy of the source core of the isotope battery;

[0065] S300: setting variable parameters of the thermocouple, and obtaining the maximum output efficiency of the isotope battery based on the variable parameters, wherein the variable parameters include at least one of a height variable, a cross-sectional area variable, and a logarithmic variable of the thermocouple.

[0066] It should be noted that the structural design method of the isotope battery 10 provided in the embodiment of the present application can be applied to COMSOL software.

[0067] It should be noted that step S100 refers to establishing a geometric model of the isotope battery 10 in COMSOL software. The established model structure of the isotope battery 10 may include a thermoelectric conversion component 11, a heat source component 12, and a structural function component 13. The thermoelectric conversion component 11 includes a thermoelectric conversion device 111. The heat source component 12 includes a source core 121.

[0068] It should be noted that the thermoelectric conversion device 111 can convert the heat energy generated by the source core 121 into electrical energy through the Seebeck effect. The Seebeck effect, also known as the first thermoelectric effect, refers to the thermoelectric phenomenon of the voltage difference between two substances caused by the temperature difference between two different electrical conductors or semiconductors. The direction of the thermoelectric potential is generally stipulated as follows: electrons flow from negative to positive at the hot end. The source core 121 can generate heat energy through the decay of radioactive isotopes.

[0069] In step S200, the output heat energy of the source core 121 of the isotope battery 10 is determined according to the decay heat of the radioactive isotope of the source core 121, and the output heat energy of the source core 121 is set in the COMSOL software to provide a calculation basis for the subsequent simulation results of the COMSOL software. Here, determining the output heat energy of the source core 121 of the isotope battery 10 means that under the established isotope battery 10 model, the output heat energy of the source core 121 remains unchanged, so that under the determined output heat energy, the variable parameters of the thermocouple 1112 are set to obtain the maximum output efficiency.

[0070] Here, the output heat energy of the source core 121 may be the heat energy that the source core 121 can generate under normal working conditions, so that the geometric model is in an environment close to the actual application conditions of the isotope battery 10 .

[0071] Here, multiple pairs of thermocouples 1112 connected in series refer to multiple pairs of thermocouples 1112 connected in series to form a whole, each pair of thermocouples 1112 includes two thermocouples 1112 with different polarities and connected in series, and illustratively, each pair of thermocouples 1112 may include a P-type thermocouple 1112 and an N-type thermocouple 1112, and the P-type thermocouple 1112 and the N-type thermocouple 1112 may be connected through an electrode sheet 1111, and each pair of adjacent thermocouples 1112 may also be connected through an electrode sheet 1111. Multiple pairs of thermocouples 1112 may be arranged in an array.

[0072] It should be noted that any adjacent P-type thermocouples 1112 and N-type thermocouples 1112 are arranged with an interval therebetween.

[0073] It is understandable that the thermocouple 1112 may have a cold end and a hot end along the height direction, the hot end is close to the source core 121 and receives heat from the source core 121, and the cold end is away from the source core 121. The thermocouple 1112 may obtain heat energy from the source core 121 by end surface heat collection.

[0074] In step S300 , the variable parameter of the thermocouple 1112 that is set may be one of the height variable, the cross-sectional area variable, and the logarithmic variable of the thermocouple 1112 , or two of them, or all three of them.

[0075] It is understandable that the height, cross-sectional area and logarithm of the thermoelectric monocouple 1112 will affect the thermoelectric conversion effect of the thermoelectric conversion device 111 , thereby affecting the overall output efficiency of the isotope battery 10 .

[0076] For example, the height variation of the thermocouple 1112 can affect the temperature difference between the hot end and the cold end of the thermocouple 1112 , thereby affecting the output electrical energy.

[0077] Exemplarily, the cross-sectional area variation of the thermocouple 1112 can affect the heating area of ​​the hot end of the thermocouple 1112 and the source core 121 , thereby affecting the output electrical energy.

[0078] Exemplarily, the logarithm of the thermoelectric monocouple 1112 can affect the contact area between the thermoelectric conversion device 111 and the source core 121 , thereby affecting the efficiency of heat transfer. In addition, the logarithm of the thermoelectric monocouple 1112 can also affect the total output power of the thermoelectric conversion device 111 .

[0079] Here, the output efficiency of the isotope battery 10 refers to the ratio of the output power of the isotope battery 10 to the output heat energy of the source core 121. The maximum output efficiency is the maximum output efficiency value under the change law obtained under the set variable parameters. When the output heat energy of the source core 121 is determined, when the isotope battery 10 is at the maximum output efficiency, the output power of the isotope battery 10 is also the maximum, and the overall reliability of the isotope battery 10 is high.

[0080] By setting at least one of the height variable, cross-sectional area variable, and logarithm variable of the thermocouple 1112 as a variable parameter, the variation law of the output efficiency of the isotope battery 10 under the changed height and / or cross-sectional area and / or logarithm is obtained according to the simulation results in the COMSOL software, so as to obtain the maximum output efficiency of the isotope battery 10, and then according to the design values ​​of the height and / or cross-sectional area and / or logarithm of the thermocouple 1112 under the maximum output efficiency, the isotope battery 10 is designed, providing a reasonable theoretical basis for the high integration and high output efficiency design of the isotope battery 10.

[0081] The structural design method of the isotope battery 10 provided in the embodiment of the present application can provide a theoretical basis for the preparation of actual isotope batteries by simulating the structural design of the isotope battery 10 in COMSOL software, setting the output heat energy of the source core 121 to be determined, and setting at least one of the height variable, cross-sectional area variable, and logarithmic variable of the thermoelectric monocouple 1112 as a variable parameter, so that the environment in which the isotope battery 10 is located is close to the environment in which the isotope battery 10 is located. By setting the variable parameters, the variation law of the output efficiency of the isotope battery 10 is obtained, thereby obtaining the maximum output efficiency of the isotope battery 10. In this way, it is convenient to design various parameters of the thermoelectric monocouple 1112 corresponding to the maximum output efficiency, so that the isotope battery 10 actually used is in the best working state. Under the condition of the determined output heat energy, the output power of the isotope battery 10 can also be in the best state, thereby improving the integration of the isotope battery 10.

[0082] In some embodiments, obtaining the maximum output efficiency of the isotope battery 10 includes:

[0083] The maximum output power of the isotope battery 10 is obtained. The maximum output power of the isotope battery 10 is the product of the maximum output efficiency of the isotope battery 10 and the output heat energy of the source core 121 .

[0084] It can be understood that the output power of the isotope battery 10 is the electrical energy converted by the thermoelectric conversion device 111 .

[0085] It should be noted that the COMSOL software can simulate and calculate the electric energy obtained by the isotope battery 10 under a given structure according to the output heat energy of the given source core 121, that is, obtain the variation law diagram of the output power of the isotope battery 10, thereby obtaining the maximum output power. When the output heat energy of the source core 121 is constant, the variation law diagram of the output power can be the variation law diagram of the output efficiency of the isotope battery 10, that is, the maximum output efficiency of the isotope battery 10 can be obtained through the maximum output power of the isotope battery 10.

[0086] In some embodiments, obtaining the maximum output efficiency of the isotope battery 10 includes:

[0087] Obtaining a thermal efficiency distribution diagram of the isotope battery 10;

[0088] Obtaining a thermoelectric efficiency distribution diagram of the isotope battery 10;

[0089] The thermal efficiency of the isotope battery 10 is the ratio of the thermal energy actually obtained by all the thermoelectric monocouples 1112 to the output thermal energy of the source core 121. The thermoelectric efficiency of the isotope battery 10 is the ratio of the electric energy actually converted by the thermoelectric conversion device 111 to the thermal energy actually obtained by the thermoelectric conversion device 111. The electric energy actually converted by the thermoelectric conversion device 111 is the output power of the isotope battery 10. The output efficiency of the isotope battery 10 is the product of the thermal efficiency of the isotope battery 10 and the thermoelectric efficiency of the isotope battery 10.

[0090] It is understandable that the output efficiency change law diagram of the isotope battery 10 can be directly obtained through the output power change law diagram of the isotope battery 10. The output efficiency change law diagram of the isotope battery 10 can also be obtained by first obtaining the thermal efficiency distribution diagram and the thermoelectric efficiency distribution diagram of the isotope battery 10 and then obtaining the output efficiency change law diagram of the isotope battery 10.

[0091] Here, by analyzing the thermal efficiency distribution diagram and the thermoelectric efficiency distribution diagram, the power conversion consumption process and change of the isotope battery 10 can be obtained. That is, the output efficiency is not necessarily the highest when the thermal efficiency is the highest, nor is it necessarily the highest when the thermoelectric efficiency is the highest.

[0092] For example, Figure 4 The cross-sectional area of ​​the thermocouple 1112 is 2.56 mm 2 , the height of the thermoelectric monocouple 1112 is 39 mm, and the thermal efficiency distribution diagram and thermoelectric efficiency distribution diagram of the isotope battery 10 are shown under different logarithms of the thermoelectric monocouple 1112. It can be seen that when the cross-sectional area and height of the thermoelectric monocouple 1112 remain unchanged, as the logarithm of the thermoelectric monocouple 1112 increases, the contact area between the thermoelectric conversion device 111 and the source core 121 increases, and the thermal power flowing through the thermoelectric conversion device 111 increases, thereby increasing the thermal efficiency of the isotope battery 10; similarly, as the logarithm of the thermoelectric monocouple 1112 increases, the contact area between the thermoelectric conversion device 111 and the source core 121 increases. According to the heat transfer formula, the temperature difference between the two ends of the thermoelectric conversion device 111 will decrease, thereby causing the thermoelectric efficiency of the isotope battery 10 to decrease as the logarithm of the thermoelectric monocouple 1112 increases. And because the output efficiency of the isotope battery 10 is the product of the thermal efficiency of the isotope battery 10 and the thermoelectric efficiency of the isotope battery 10, therefore Figure 4 The total efficiency in the isotope battery 10, that is, the output efficiency of the isotope battery 10, shows a trend of first increasing and then decreasing as the logarithm of the thermoelectric monocouple 1112 increases, so that the output efficiency of the isotope battery 10 has a maximum value. Figure 4 In the case of , the output efficiency of the isotope battery 10 is maximum when the number of pairs of the thermocouple 1112 is 50.

[0093] It is understandable that, depending on the cross-sectional area and height of the thermocouple 1112, Figure 4 The horizontal axis value in will change, that is, the logarithm of the thermoelectric monocouple 1112 corresponding to the maximum output efficiency of the isotope battery 10 will change.

[0094] It should be noted that in this embodiment, by arbitrarily determining two parameter values ​​among the cross-sectional area value, height value, and logarithmic value of the thermocouple 1112, and setting the remaining parameter value as a variable parameter, the changing trend of the output efficiency of the isotope battery 10 during the change of the variable parameter under the determined parameter value can be obtained, thereby providing a theoretical basis for the design of the isotope battery 10.

[0095] In some embodiments, setting the variable parameters of the thermocouple 1112 includes:

[0096] The height value and logarithmic value of the thermocouple 1112 are arbitrarily determined, and the cross-sectional area variable of the thermocouple 1112 is set.

[0097] In this way, it can be obtained that when the height value and logarithmic value of the thermocouple 1112 remain unchanged, the changing trend of the output efficiency of the isotope battery 10 during the change of the cross-sectional area of ​​the thermocouple 1112 can increase the simulation reliability and facilitate the acquisition of reliable maximum output efficiency.

[0098] In some embodiments, setting the variable parameters of the thermocouple 1112 includes:

[0099] Take the logarithmic value and cross-sectional area value of the thermocouple 1112 determined arbitrarily, and set the height variable of the thermocouple 1112. Thus, the change trend of the output efficiency of the isotope battery 10 during the change of the height of the thermocouple 1112 is obtained when the logarithmic value and cross-sectional area value of the thermocouple 1112 remain unchanged. Only a single variable is changed, which can increase the reliability of the simulation and facilitate the reliable maximum output efficiency.

[0100] In some embodiments, setting the variable parameters of the thermocouple 1112 includes:

[0101] Take any determined height value and cross-sectional area value of the thermocouple 1112, and set the logarithmic variable of the thermocouple 1112. Thus, the change trend of the output efficiency of the isotope battery 10 during the change of the logarithm of the thermocouple 1112 is obtained when the height value and cross-sectional area value of the thermocouple 1112 remain unchanged. Only a single variable is changed, which can increase the reliability of the simulation and facilitate the reliable maximum output efficiency.

[0102] It can be understood that at least two of the above three embodiments can be combined.

[0103] Exemplarily, in some embodiments, setting the variable parameters of the thermocouple 1112 includes:

[0104] Obtaining the cross-sectional area and height of the isotope battery 10 at any determined logarithm and at maximum output power;

[0105] Set the logarithmic variable of the thermocouple 1112.

[0106] Here, the optimal cross-sectional area value and height value are first obtained, then the logarithm of the thermocouple 1112 is changed, and then the output power variation diagram is obtained, and then the optimal logarithmic value is obtained therefrom.

[0107] It should be noted that in the step of obtaining the cross-sectional area value of the isotope battery 10 at the maximum output power, the cross-section of the thermocouple 1112 can be rectangular, circular or convex polygonal, etc., and is not limited here.

[0108] Exemplarily, the cross section of the thermocouple 1112 is a square, and obtaining the cross-sectional area value of the isotope battery 10 at the maximum output power is equivalent to obtaining the cross-sectional side length value of the isotope battery 10 at the maximum output power.

[0109] In the step of obtaining the height value of the isotope battery 10 at the maximum output power, the height value of the thermoelectric monopole 1112 needs to be selected according to the maximum output power of the isotope battery 10, and factors such as manufacturing process and mechanical properties also need to be considered. It can be understood that the larger the height value of the thermoelectric monopole 1112, the greater the processing difficulty, and the worse the mechanical properties of the thermoelectric device, and the more likely it is to break.

[0110] In this embodiment, the cross-sectional area value and height value under a certain logarithm and at the maximum output efficiency are first obtained, and then based on this, the logarithm value is changed to obtain the output power change graph corresponding to the changed logarithm value, thereby obtaining the maximum output power. In this way, on the one hand, it is simple and reliable and reduces the number of simulations. On the other hand, it can also make the height value, cross-sectional area value and logarithm value corresponding to the maximum output power finally obtained close to the optimal situation, so that the final isotope battery 10 obtained by simulation is in the best working state.

[0111] In some embodiments, obtaining the cross-sectional area value and the height value of the isotope battery 10 at the maximum output power includes:

[0112] Taking the logarithmic value of any determined thermoelectric monocouple 1112, determining a plurality of different cross-sectional area values, setting the height variable of the thermoelectric monocouple 1112, and obtaining the power output distribution diagram of the isotope battery 10 at each cross-sectional area value;

[0113] A plurality of power output distribution diagrams obtained under a plurality of different cross-sectional area values ​​are fitted to obtain the height value and the cross-sectional area value corresponding to the maximum output power.

[0114] For example, see Figure 3 , Figure 3 It is an overlay diagram of the output efficiency of the isotope battery 10 and the height change curve of the thermocouple 1112 under multiple different cross-sectional area values. Under the overlay of multiple output efficiency distribution diagrams, it can be concluded that the maximum output efficiency of the change curve of a certain cross-sectional area value is higher than the output efficiency of the change curve of other cross-sectional area values. The output efficiency distribution diagram corresponding to the cross-sectional area value is selected, and the height value corresponding to the highest output efficiency of the cross-sectional area value is obtained, thereby determining the cross-sectional area value and height value of the thermocouple 1112.

[0115] It should be noted that the cross-sectional area value of the thermocouple 1112 needs to be selected not only based on the maximum output power of the isotope battery 10 , but also needs to consider factors such as manufacturing process and mechanical properties.

[0116] In some embodiments, the multiple different cross-sectional area values ​​vary linearly.

[0117] In this embodiment, a plurality of different cross-sectional area values ​​vary linearly, which can make the fitted plurality of power output distribution diagrams more reliable and facilitate obtaining the height value and cross-sectional area value at the maximum output efficiency.

[0118] In some embodiments, obtaining the maximum output efficiency of the isotope battery 10 includes:

[0119] Based on the logarithmic variable of the thermoelectric monocouple 1112, an output power distribution diagram of the isotope battery 10 is obtained;

[0120] Obtaining the maximum output power of the isotope battery 10 and a logarithmic value at the maximum output power;

[0121] The maximum output efficiency of the isotope battery 10 is determined.

[0122] It should be noted that the output power distribution diagram obtained in this embodiment needs to be obtained after the cross-sectional area value and the height value of the thermocouple 1112 are determined.

[0123] Exemplarily, by first obtaining the cross-sectional area value and height value of the thermocouple 1112 corresponding to the maximum output power under a certain logarithm, and then changing the logarithm of the thermocouple 1112 based on the cross-sectional area value and the height value, the output power distribution diagram of the isotope battery 10 under different logarithms of the thermocouple 1112 is obtained, so that the cross-sectional area value, height value and logarithm value of the thermocouple 1112 corresponding to the maximum output efficiency of the isotope battery 10 can be theoretically determined.

[0124] For some examples, see Figure 2After obtaining the maximum output efficiency of the isotope battery 10, the structural design method further includes:

[0125] Based on the variable parameters corresponding to the maximum output efficiency, determining the corresponding geometric model of the isotope battery 10;

[0126] Obtaining a temperature distribution diagram of each structure of the isotope battery 10;

[0127] Based on the temperature distribution graph, it is determined whether the isotope battery 10 is within a preset operating temperature range.

[0128] It should be noted that the preset operating temperature range of the isotope battery 10 is determined according to the material of each component, and the intersection of the allowable operating temperature ranges of each component of the isotope battery 10 is taken as the preset operating temperature range of the isotope battery 10.

[0129] Specifically, the preset operating temperature range of the thermoelectric conversion device 111 is determined by the material of the thermocouple 1112 and the material of the electrode sheet 1111. For example, the material of the thermocouple 1112 is bismuth telluride, and the preset operating temperature range of the thermocouple 1112 is below 600°C.

[0130] It should be noted that the temperature distribution diagram in step S402 is the result of temperature simulation of various structural parts of the isotope battery 10 in COMSOL software.

[0131] In this embodiment, after obtaining the variable parameters corresponding to the maximum output efficiency, the temperature distribution diagram of the isotope battery 10 in this case is obtained. After determining that it is within the preset operating temperature range, it is possible to confirm whether all components of the isotope battery 10 are within the preset operating temperature range, and then confirm whether the design scheme of the isotope battery 10 is reasonable and feasible, thereby improving the situation where the isotope battery 10 has an unreasonable operating temperature while obtaining the maximum output efficiency.

[0132] For example, Figure 6 and Figure 7 As shown, the cross-sectional area of ​​the thermocouple 1112 is 2.56 mm 2 , the temperature distribution diagram of each part of the isotope battery 10 when the height of the thermocouple 1112 is 39 mm and the number of pairs of the thermocouple 1112 is 50.

[0133] For some examples, see Figure 2 , the structural design method of the isotope battery 10 is as follows:

[0134] S100: Establishing a geometric model of an isotope battery, wherein the thermoelectric conversion device of the isotope battery includes a plurality of pairs of thermoelectric monocouples connected in series, each pair of thermoelectric monocouples includes two thermoelectric monocouples with different polarities and connected in series, and the spacing between any two thermoelectric monocouples is 0.2 mm. The thermoelectric conversion device is placed close to the end surface of the source core;

[0135] S200: determining the output heat energy of the source core of the isotope battery;

[0136] S301: determining a logarithm, determining a first cross-sectional area value, setting a height variable range, and calculating the output efficiency of the isotope battery at different thermoelectric single couple heights through COMSOL software simulation according to the established geometric model of the isotope battery to obtain a first change trend graph;

[0137] Determine the second cross-sectional area value, set the same height variable range, and obtain a second change trend graph;

[0138] Determine a third cross-sectional area value, set the same height variable range, and obtain a third change trend graph;

[0139] Determine a fourth cross-sectional area value, set a same height variable range, and obtain a fourth change trend graph;

[0140] Fitting the first change trend graph, the second change trend graph, the third change trend graph, and the fourth change trend graph to obtain the height value and the cross-sectional area value corresponding to the maximum output efficiency;

[0141] S302: according to the height value and the cross-sectional area value obtained in S301, the logarithm of the thermoelectric single couple is changed, and the output efficiency distribution diagram of the isotope battery under different logarithms of the thermoelectric single couple is simulated and calculated by COMSOL software, so as to obtain the maximum output efficiency and the logarithm value corresponding to the maximum output efficiency;

[0142] S400: Based on the height value and cross-sectional area value obtained in S301 and the logarithmic value obtained in S302, determine the corresponding geometric model of the isotope battery; obtain the temperature distribution diagram of each part of the isotope battery structure; based on the temperature distribution diagram, determine whether the isotope battery is within a preset operating temperature range.

[0143] For example, see Fig. 9 , the cross section of the thermocouple 1112 is a square, see Figure 3 In step 301, the first cross-sectional area value is 2.25 mm 2 , the second cross-sectional area value is 2.56mm 2 , the third cross-sectional area value is 2.89mm 2 , the fourth cross-sectional area value is 3.24mm 2, corresponding to the cases where the cross-sectional side length is 1.5mm, 1.6mm, 1.7mm, and 1.8mm respectively. The first change trend graph, the second change trend graph, the third change trend graph, and the fourth change trend graph are respectively Figure 3 By fitting and superimposing the four curves, the maximum battery output efficiency at each height value and cross-sectional area value can be obtained, and the curve with the maximum battery output efficiency is obtained, and the height value and cross-sectional area value corresponding to the maximum battery output efficiency on the curve are taken as the height value and cross-sectional area value finally obtained in step S301.

[0144] It should be noted that, in step S302, the height value and the cross-sectional area value are fixed values.

[0145] For example, the cross-sectional area of ​​the thermocouple 1112 obtained in step S301 is 2.56 mm 2 The height of the thermocouple 1112 is 39 mm. In step S302, the cross-sectional area is 2.56 mm. 2 When the height is 39 mm, the output efficiency distribution diagram of the isotope battery is shown in the following figure under different logarithms of thermoelectric single couples through COMSOL software simulation calculation. Figure 5 shown.

[0146] The second aspect of the embodiment of the present application provides an isotope battery 10, which adopts the structural design method provided by any embodiment of the present application. Figures 8 to 10 The isotope battery 10 includes a housing assembly 135, a source core 121, and a thermoelectric conversion device 111. The housing assembly 135 includes a housing body 1351 and an end cover 1352, wherein the end cover 1352 is disposed at one end of the housing body 1351 along the axial direction to define a closed accommodation space. The source core 121 is disposed in the accommodation space for dissipating heat energy. The thermoelectric conversion device 111 is disposed in the accommodation space, and the thermoelectric conversion device 111 is used to convert the heat energy of the source core 121 into electrical energy. The cross-sectional area of ​​the thermoelectric monopole 1112 is 1 mm 2 ~4mm 2 ; and / or, the height of the thermocouple 1112 is 30 mm to 50 mm; and / or, the number of pairs of the thermocouple 1112 is 40 to 60. That is, the parameters of the thermocouple 1112 of the isotope battery 10 in this embodiment can only meet the cross-sectional area of ​​1 mm 2 ~4mm 2 , one of the following three conditions may be met: height is 30mm~50mm, and logarithm is 40~60; two of the three conditions may be met at the same time; or all three may be met at the same time.

[0147] For example, the cross-sectional area of ​​the thermocouple 1112 is 1 mm 2 , 2mm2 , 2.25mm 2 、2.56mm 2 , 2.89mm 2 , 3mm 2 、3.24mm 2 or 4mm 2 This is beneficial to the miniaturization design of the thermoelectric conversion device 111 , increasing the number of thermoelectric single couples 1112 connected in series, and improving the output power of the thermoelectric conversion device 111 .

[0148] Exemplarily, the height of the thermocouple 1112 is 30 mm, 35 mm, 39 mm, 40 mm, 45 mm or 50 mm, etc. In this way, the thermocouple 1112 can generate a sufficient temperature difference at both ends of the height to improve the efficiency of thermoelectric conversion.

[0149] Exemplarily, the number of pairs of the thermoelectric monopole 1112 is 40, 42, 45, 48, 50, 52, 55, 58, 59 or 60, etc. In this way, the thermoelectric conversion device 111 can convert and output sufficient electrical energy, and at the same time, it can also improve the situation where the temperature difference between the two ends of the thermoelectric conversion device 111 is insufficient due to the excessive contact area between the thermoelectric conversion device 111 and the heat source component 12.

[0150] For example, the cross-sectional area of ​​the thermocouple 1112 is 2.56 mm 2 , the height of the thermocouple 1112 is 39 mm, and the number of pairs of the thermocouple 1112 is 50. In this case, the battery output voltage is 0.54 V, the open circuit voltage is 1.07 V, the short circuit current is 0.022 A, the internal resistance is 24.4 Ω, and the maximum output efficiency of the battery is 1.18%. At the same time, the temperature distributions of the isotope battery 10 and the thermoelectric device are as follows: Figure 6 and Figure 7 As shown, from Figure 6 and Figure 7 It can be seen that all components of the isotope battery 10 are within the preset operating temperature range, and the design scheme is reasonable and feasible.

[0151] Exemplarily, the isotope battery 10 includes a thermoelectric conversion component 11, a heat source component 12, and a structural functional component 13. The structural functional component 13 includes a heat collector 131, a heat-conducting tube 132, an insulation layer 133, a shielding layer 134, and a shell component 135, wherein the battery is composed of a shell component 135, a shielding layer 134, and an insulation layer 133 from the outside to the inside, and the heat source component 12 and the thermoelectric conversion component 11 are arranged in the insulation layer 133. The shielding layer 134 is used to shield the radiation of the radioactive heat source component 12, the heat source component 12 provides thermal energy for the isotope battery 10, and the insulation layer 133 is used to reduce the loss of heat emitted by the heat source component 12. The heat source component 12 includes a source core 121, a pressure head 122, a tungsten liner 123, a sealing cladding 124, and a structural cladding 125. The heat-conducting tube 132 is sleeved outside the heat source component 12, and the heat collector 131 is arranged on one end surface of the heat source component 12 close to the source core 121. The thermoelectric conversion component 11 includes a thermoelectric conversion device 111 and a substrate 112 arranged at both ends of the thermoelectric conversion device 111. The thermoelectric conversion device 111 may include an electrode sheet 1111, a P-type thermoelectric monocouple 1112, and an N-type thermoelectric monocouple 1112, wherein the P-type thermoelectric monocouple 1112 and the N-type thermoelectric monocouple 1112 constitute a pair of thermoelectric monocouples 1112. A plurality of pairs of thermocouples 1112 are arranged in a matrix, and a certain gap is maintained between each pair of thermocouples 1112. The P-type thermocouple 1112 and the N-type thermocouple 1112 of each pair of thermocouples 1112 are connected at one end in the height direction by an electrode sheet 1111, and the other end is connected to a different type of thermocouple 1112 of any adjacent pair of thermocouples 1112 by the electrode sheet 1111, thereby forming an electrical series and thermal parallel relationship between the plurality of pairs of thermocouples 1112.

[0152] Exemplarily, one end of the thermoelectric conversion component 11 along the height direction is connected to the collector 131, so that the collector 131 and the heat conductive tube 132 can transfer the heat of the heat source component 12 to the thermoelectric conversion component 11 as much as possible, thereby improving the efficiency of transferring the heat of the heat source component 12 to the thermoelectric conversion device 111.

[0153] It should be noted that the efficiency of transferring heat from the heat source component 12 to the thermoelectric conversion device 111 is the thermal efficiency in this application.

[0154] Exemplarily, the gap between the thermoelectric monocouples 1112 ranges from 0.1 mm to 0.2 mm, which reduces the size of the thermoelectric conversion device 111 and improves the integration level.

[0155] It should be noted that the gaps between the thermocouples 1112 may be filled with insulating glue.

[0156] Exemplarily, the insulating adhesive includes polyimide.

[0157] Exemplarily, the material of the substrate 112 of the thermoelectric conversion component 11 is ceramic.

[0158] The isotope battery 10 provided in the embodiment of the present application, through the structural design method of the isotope battery 10, according to the output heat energy of the source core 121 set in the COMSOL software and the simulation results of the COMSOL software, obtains the parameter value of the thermoelectric monocouple 1112 at the maximum output efficiency of the isotope battery 10, and by setting the cross-sectional area of ​​the thermoelectric monocouple 1112 to 1mm 2 ~4mm 2 The height of the thermocouple 1112 is set to 30 mm to 50 mm, and the logarithm of the thermocouple 1112 is set to 40 to 60, which improves the integration and output efficiency of the isotope battery 10. At the same time, the temperature simulation result of the isotope battery 10 under this parameter is also within the preset operating temperature range, thereby improving the stability and reliability of the isotope battery 10.

[0159] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0160] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A structural design method for an isotope battery, applied to COMSOL software, characterized in that: The structural design method comprises: Establishing a geometric model of the isotope battery, wherein the thermoelectric conversion device of the isotope battery includes a plurality of pairs of thermoelectric monocouples connected in series, and each pair of the thermoelectric monocouples includes two thermoelectric monocouples with different polarities and connected in series; determining the output heat energy of the source core of the isotope battery; The variable parameters of the thermocouple are set, and based on the variable parameters, the maximum output efficiency of the isotope battery is obtained, wherein the variable parameters include at least one of a height variable, a cross-sectional area variable, and a logarithmic variable of the thermocouple.

2. The structural design method according to claim 1, characterized in that: The obtaining of the maximum output efficiency of the isotope battery comprises: The maximum output power of the isotope battery is obtained, wherein the maximum output power of the isotope battery is the product of the maximum output efficiency of the isotope battery and the output thermal energy of the source core.

3. The structural design method according to claim 1, characterized in that: The obtaining of the maximum output efficiency of the isotope battery comprises: Obtaining a thermal efficiency distribution diagram of the isotope battery; Obtaining a thermoelectric efficiency distribution diagram of the isotope battery; Among them, the thermal efficiency of the isotope battery is the ratio of the thermal energy actually obtained by all the thermoelectric monocouples to the output thermal energy of the source core, and the thermoelectric efficiency of the isotope battery is the ratio of the electric energy actually converted by the thermoelectric conversion device to the thermal energy actually obtained by the thermoelectric conversion device; the electric energy actually converted by the thermoelectric conversion device is the output power of the isotope battery, and the output efficiency of the isotope battery is the product of the thermal efficiency of the isotope battery and the thermoelectric efficiency of the isotope battery.

4. The structural design method according to claim 1, characterized in that: The variable parameters of the thermocouple are set as follows: Taking the height value and logarithmic value of the thermocouple determined arbitrarily, and setting the cross-sectional area variable of the thermocouple; and / or, taking the logarithmic value and cross-sectional area value of the thermocouple determined arbitrarily to set the height variable of the thermocouple; And / or, taking any determined height value and cross-sectional area value of the thermocouple to set the logarithmic variable of the thermocouple.

5. The structural design method according to claim 1, characterized in that: The variable parameters of the thermocouple are set as follows: Obtaining a cross-sectional area value and a height value of the isotope battery at any determined logarithm and at maximum output power; Set the logarithmic variable of the thermocouple.

6. The structural design method according to claim 5, characterized in that: The obtaining of the cross-sectional area value and the height value of the isotope battery at the maximum output power comprises: Taking any determined logarithmic value of the thermoelectric monocouple, determining a plurality of different cross-sectional area values, setting a height variable of the thermoelectric monocouple, and obtaining a power output distribution diagram of the isotope battery at each cross-sectional area value; A plurality of power output distribution diagrams obtained under a plurality of different cross-sectional area values ​​are fitted to obtain the height value and the cross-sectional area value corresponding to the maximum output power.

7. The structural design method according to claim 6, characterized in that: Several different cross-sectional area values ​​vary linearly.

8. The structural design method according to claim 5, characterized in that: The obtaining of the maximum output efficiency of the isotope battery comprises: Based on the logarithmic variable of the thermoelectric monocouple, obtaining an output power distribution diagram of the isotope battery; Obtain the maximum output power of the isotope battery and its logarithmic value at the maximum output power; The maximum output efficiency of the isotope battery is determined.

9. The structural design method according to claim 1, characterized in that: After obtaining the maximum output efficiency of the isotope battery, the structural design method further includes: Based on the variable parameters corresponding to the maximum output efficiency, determining the corresponding geometric model of the isotope battery; Obtaining a temperature distribution diagram of each structure of the isotope battery; Based on the temperature distribution diagram, it is determined whether the isotope battery is within a preset operating temperature range.

10. An isotope battery, using the structural design method according to any one of claims 1 to 9, characterized in that: include: The housing assembly comprises an outer housing and an end cover, wherein the end cover is arranged at one end of the outer housing along the axial direction to define a closed accommodation space; A source core, disposed in the accommodation space, for dissipating heat energy; A thermoelectric conversion device is disposed in the accommodation space, and is used to convert the thermal energy of the source core into electrical energy; The cross-sectional area of ​​the thermocouple is 1 mm 2 ~4mm 2 ; And / or, the height of the thermocouple is 30 mm to 50 mm; And / or, the number of pairs of the thermoelectric monocouples is 40-60.

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