JP7385260B2 - Nuclear battery, nuclear battery system - Google Patents

Description

The present invention relates to a nuclear battery that generates power using radiation emitted from a radiation source, and a nuclear battery system in which nuclear batteries are combined.

Nuclear batteries, which convert radiation emitted by radioactive isotopes (sources) with long half-lives into electrical energy (electromotive force) and output them, can be used for long periods of time by using sources with long half-lives. It is widely used, especially in unmanned exploration equipment (space probes, etc.). In order to convert the energy of radiation into electrical energy, there are techniques that convert the heat generated by absorption of radiation into electrical energy using the thermoelectric effect (for example, Non-Patent Document 1), and methods that convert radiation into light such as visible light. However, a technique is used in which a solar cell converts this light into electrical energy by photoelectric conversion in a semiconductor (for example, Patent Document 1).

In the former, a thermoelectric conversion element is used that is composed of two types of semiconductor layers having different Seebeck coefficients and electrodes connected to these layers. In the latter, a structure using a semiconductor similar to a solar cell that generates electricity by absorbing visible light is used, and in this case, a phosphor that emits visible light by absorbing radiation is used, and this visible light is In some cases, it is configured to be absorbed by a solar cell.

If a radiation source with a sufficiently long half-life is used, it is expected that the battery will have a lifespan of 100 years or more, which cannot be achieved with other batteries. However, while nuclear cells generate electricity using radiation as described above, this radiation causes crystal defects in the semiconductor materials that make up thermoelectric conversion elements and solar cells (thermoelectric conversion elements, etc.). . These crystal defects deteriorate the characteristics of thermoelectric conversion elements, etc., and in reality, the lifespan of nuclear batteries is often determined by such deterioration of thermoelectric conversion elements, and it is not easy to obtain the long lifespan described above. . Particularly, radiation that causes crystal defects in this manner includes gamma rays. Furthermore, even when a radiation source emits radiation other than gamma rays, gamma rays may be emitted as secondary radiation from this radiation. For this reason, nuclear batteries require shielding to prevent damage caused by radiation exposure to thermoelectric conversion elements, etc., but this shielding structure essentially increases the size and weight of the nuclear battery. .

From this point of view, the above-mentioned radiation sources include ²³⁸ Pu and ²¹⁰ Po etc. are used.

Japanese Patent Application Publication No. 54-032281

Japan Atomic Energy Agency, National Research and Development Agency, Atomic Energy Encyclopedia ATOMICA, <Title> Nuclear Battery, URL: https://atomica. jaea. go. jp/data/detail/dat_detail_08-04-02-08. html

However, even when such a radiation source and shield are used, the actual lifespan of nuclear batteries is determined by the deterioration of thermoelectric conversion elements and other components caused by radiation, and is significantly shorter than the half-life of the radiation source. Furthermore, ²³⁸ Pu and ²¹⁰ Po used as radiation sources are very expensive because they are not easy to manufacture or are rare.

For this reason, there has been a desire for nuclear batteries that are small, have a long life, and are less susceptible to deterioration due to radiation.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configuration.
The nuclear battery of the present invention is a nuclear battery in which a radiation source that constantly emits radiation and a thermoelectric conversion element that generates an electromotive force between a first electrode and a second electrode due to a temperature gradient generated by the radiation are combined. The thermoelectric conversion element is formed on a substrate, and is composed of a ferromagnetic layer having a magnetic field in an in-plane direction, and a metal material that exhibits a reverse spin Hall effect. and a metal layer with a thickness of 50 nm or less formed at a location where the first electrode and the second electrode are spaced apart in the in-plane direction and the direction intersecting the magnetic field, and the radiation is a neutron beam. The radiation source is connected to the thermoelectric conversion element to generate the temperature gradient in the thickness direction of the ferromagnetic layer, and the substrate is made of gallium gadolinium garnet (GGG). ) and is characterized by being coated with boron (B) or cadmium (Cd) .
The nuclear battery of the present invention is characterized in that a magnetic field application layer that applies the magnetic field to the ferromagnetic layer and the metal layer is connected to the end portions of the ferromagnetic layer and the metal layer in the in-plane direction. shall be.
In the nuclear power cell of the present invention, the ferromagnetic layer is made of yttrium-iron-garnet (YIG) or YIG added with gallium (Ga).
In the nuclear battery of the present invention, the metal layer includes platinum (Pt), gold (Au), niobium (Nb), nickel (Ni), or stainless steel.
In the nuclear power cell of the present invention, the radiation source is connected to a side of the substrate opposite to the side on which the ferromagnetic layer is formed.
In the nuclear battery system of the present invention, a plurality of nuclear batteries are arranged and connected in series so that the magnetic field in each of them is in a common direction, and the first electrode and the second electrode in each of them are on a common side. It is characterized in that it is formed on a supporting base.
In the nuclear battery system of the present invention, the support base has a substantially cylindrical shape, and a plurality of the nuclear cells are arranged along the circumferential direction of the outer peripheral surface of the substantially cylindrical shape.
The nuclear battery system of the present invention is characterized in that the support base is made of a material that constantly emits the radiation, and the support base also serves as the radiation source in each of the nuclear batteries.

Since the nuclear power cell of the present invention is configured as described above, it suffers less deterioration due to radiation and has a long life.

FIG. 1 is a cross-sectional perspective view showing the structure of a nuclear battery according to an embodiment of the present invention. It is the result of measuring the magnetic field dependence of the output voltage in an example of the present invention. It is the temperature difference dependence of the output voltage in the example before γ-ray irradiation (a) and after γ-ray irradiation in a high temperature and dry atmosphere (b). The temperature difference dependence of the output voltage for each gamma ray exposure dose (a) and the exposure dose dependence of the temperature coefficient (b) in gamma ray irradiation at high temperature and in steam are shown, respectively. 1 is a diagram illustrating an example of a configuration of a nuclear battery system in which a plurality of nuclear batteries are combined according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the structure of another example of the nuclear battery system according to the embodiment of the present invention.

Hereinafter, a nuclear battery and a nuclear battery system according to an embodiment of the present invention will be described. This nuclear battery is similar to conventional nuclear batteries in that it generates electricity using heat caused by radiation emitted from the radiation source used, but its structure and power generation mechanism are different from conventional nuclear batteries. different.

In conventional nuclear batteries that convert heat into electrical energy, p-type and n-type semiconductor layers, for example, are used to utilize the Seebeck effect of semiconductors. Electromotive force is generated due to the flow of holes and electrons in the n-type semiconductor.

On the other hand, the nuclear battery of the present invention utilizes the spin Seebeck effect described in, for example, JP-A-2009-130070 and JP-A-2015-179746. In thermoelectric conversion elements that use the spin Seebeck effect, when a magnetic field is applied to the ferromagnetic layer or when the ferromagnetic layer is magnetized, electrons flow parallel to the magnetic field (up-spin electrons). , a difference is created in the flow of electrons with antiparallel spins (down-spin electrons), and this difference is output as a voltage (electromotive force) due to the reverse spin Hall effect in the paramagnetic metal layer that is in contact with the ferromagnetic layer. .

In a thermoelectric conversion element that utilizes the Seebeck effect in a semiconductor as described above, the flow of holes and electrons that generate electromotive force is greatly affected by crystal defects in the semiconductor. Since these crystal defects are generated particularly by radiation irradiation, they increase over time in an environment with a high radiation dose, and the output voltage decreases accordingly.

On the other hand, as will be described later, the spin current in a ferromagnetic material is less affected by radiation irradiation than the flow of holes and electrons in a semiconductor. Therefore, a thermoelectric conversion element using such a spin Seebeck effect is particularly suitable for use in an environment with a high radiation dose.

FIG. 1 is a cross-sectional perspective view showing the structure of a nuclear power cell 1 according to an embodiment of the present invention. In this nuclear cell 1, a ferromagnetic insulating layer 20 and a metal layer 30 are sequentially formed on a substrate 10 along the film thickness direction (z direction). In this nuclear battery 1, a thermoelectric conversion element 5 is constituted by a ferromagnetic insulating layer (ferromagnetic layer) 20 and a metal layer 30.

Further, a radiation source (heat source) 40 that emits radiation is connected to the lower side of the substrate 10. Furthermore, magnetic field application layers 51 and 52 are connected to both sides of this structure in the x direction, respectively. If the metal layer 30 were made thick enough to have negligible sheet resistance, the metal layer 30 would have the same potential in the in-plane direction, but as will be described later, since the metal layer 30 is formed sufficiently thin, the metal layer 30 A potential difference occurs in the in-plane direction of the layer 30. Since a potential difference due to the spin Seebeck effect occurs in the y-axis direction in the figure, a first electrode 31 and a second electrode 32 are connected to both ends of the metal layer 30 in the y-axis direction, and the first electrode 31 and the second electrode An electromotive force (voltage) V0 is extracted between the electrodes 32.

As the substrate 10, a material having sufficient mechanical strength and on which a high-quality ferromagnetic insulating layer 20 can be formed is used. For example, a 1 mm thick Gd ₃ Ga ₅ O ₁₂ (gadolinium gallium garnet) :GGG) single crystal is used. As the ferromagnetic insulating layer (ferromagnetic layer) 20, a ferrite magnetic material such as Y ₃ Fe ₅ O ₁₂ (yttrium-iron-garnet: YIG), which is magnetic garnet, or YIG added with gallium (Ga) is used. It has a thickness of about 100 nm and is formed by a coating printing method, a sputtering method, or the like. Since the spin Seebeck effect can be obtained even when a conductive (metal) ferromagnetic layer is used instead of the ferromagnetic insulating layer 20, other ferromagnetic materials can also be used, such as magneto-optical materials such as MnSb and MnBi. Materials and rare earth compounds such as SmCo can also be used. However, when a thick conductive ferromagnetic layer is used, it is difficult to obtain an electromotive force between the first electrode 31 and the second electrode 32, as in the case where the metal layer 30 is thick as described above. Therefore, it is preferable to use the ferromagnetic insulating layer 20.

As the metal layer 30, metal materials such as platinum (Pt), gold (Au), niobium (Nb), nickel (Ni), stainless steel, etc., which have a large spin-orbit interaction and strongly exhibit a reverse spin Hall effect, are preferably used. . As described above, the thickness of the metal layer 30 is sufficiently thin, 50 nm or less, for example, about 10 nm, so that the sheet resistance is sufficiently high even when a conductive metal material is used. The metal layer 30 is formed by, for example, a sputtering method. The electromotive force generated in this nuclear battery 1 is extracted from the first electrode 31 and the second electrode 32 as described above.

The magnetic field applying layers 51 and 52 are each made of a hard magnetic material having spontaneous magnetization in the illustrated direction, and are insulating or provided on both sides in the x direction so as to be insulated from the metal layer 30 etc. There is. The magnetic field applying layers 51 and 52 apply a magnetic field H to the ferromagnetic insulating layer 20 in the in-plane direction from the negative side to the positive side in the x direction in FIG.

As the radiation source 40, a radiation source that generates heat due to the radiation it emits and has a sufficiently long half-life can be used as appropriate, similar to a conventional nuclear battery. A temperature gradient ΔT (heat flow) towards the For this reason, the material constituting the radiation source 50 can be ²³⁸ Pu or ²¹⁰ Po, which emit alpha rays, similar to conventional nuclear batteries. Since the layer 20 and the metal layer 30) are less likely to be degraded by radiation irradiation, a radiation source 40 that emits radiation other than α-rays can be used. Specifically, ¹⁰ Be that emits β rays (half-life 1.4 × 10 ⁶ years, β ray energy 0.6 MeV; the same applies to years and energy descriptions below), ¹⁴ C (5.7 × 10 ^{3 26} Al (7.2 × 10 ⁵ years, 1.2 MeV), ³² Si (1.7 × 10 ² years, 0.1 MeV), ³⁶ Cl (3.0 × 10 ⁵ years, 0.7 MeV), ³⁹ Ar (2.7 x 10 ² years, 0.6 MeV), ⁴⁰ K (1.3 x 10 ⁹ years, 1.3 MeV), ⁶³ Ni (1.0 x 10 ² years, 0. 07 MeV), ⁷⁹ Se (6.4 x 10 ⁴ years, 0.16 MeV), ⁸⁷ Rb (5.0 x 10 ¹⁰ years, 0.3 MeV), ⁹³ Zr (1.5 x 10 ⁵ years, 0.06 MeV) , ¹¹⁵ In (3×10 ¹⁹ years, 0.6 MeV), ¹³⁷ Cs (30 years, 0.5 MeV), ¹³⁸ La (1×10 ¹¹ years, 1.4 MeV) can be used. In addition, ⁹⁴ Nb (2.0 x 10 ⁴ years, β rays 0.4 MeV, γ rays 0.7 MeV), ⁹⁸ TC (4.2 x 10 ⁶ years, β rays 0.3 MeV, γ ray 0.6 MeV), 176Lu (1×1010 years, β ray 0.4 MeV, γ ray 0.3 MeV) can be used. In addition, ¹⁴⁴ Nd (2 x 10 ¹⁵ years, 1.9 MeV), ¹⁴⁶ Sm (1 x 10 ¹⁸ years, 2.6 MeV), ¹⁴⁷ Sm (1 x 10 ¹¹ years, 2.7 MeV), ¹⁵² Gd that emit alpha rays (1×10 ¹⁴ years, 2.7 MeV), ¹⁹⁰ Pt (6×10 ¹¹ years, 3 MeV), ²¹⁰ Bi (2×10 ⁶ years, 4.9 MeV), ²⁰⁹ Po (10 ³ years, 4.9 MeV), ²³² Th (1×10 ¹⁰ years, 4MeV), ²³² U, ²³³ U, ²³⁴ U, ²³⁵ U, ²³⁶ U, ²³⁸ U (4 MeV), ²³⁶ Pu, ²³⁸ Pu, ²³⁹ Pu, ²⁴⁴ Pu (5 MeV), ²⁴¹ Am , ²⁴³ Am (5 MeV), ²⁴⁶ Cm, ²⁴⁷ Cm, ²⁴⁸ Cm (5 MeV), ²⁴⁹ Cf, ²⁵¹ Cf (6 MeV) can be used.

In addition, by using a combination in which the radiation emitted by the radiation source 40 is easily absorbed by the substrate 10, the power generation efficiency can be increased, especially by making the substrate 10 more likely to generate heat. For example, when the material of the substrate 10 is GGG containing Gd with a large neutron capture cross section, a material that emits neutrons can also be used as the radiation source 40. In this case, power generation efficiency can be further improved by coating the substrate 10 with boron (B) or cadmium (Cd), which have a large reaction cross section with neutrons, for example. Even in this case, the temperature gradient formed is as shown in FIG.

In the above structure, the spin Seebeck effect in the ferromagnetic insulating layer 20 and the reverse spin Hall effect in the metal layer 30 are similar to the structures described in JP 2009-130070A and JP 2015-179746A. Accordingly, the electromotive force due to the temperature gradient and the magnetic field can be taken out from the metal layer 30. On the other hand, when the metal layer 30 is a ferromagnetic material, the abnormal Nernst effect as described in JP-A-2016-103535, for example, occurs in the metal layer 30 regardless of the presence or absence of the ferromagnetic insulating layer 20. do. The direction of the electromotive force (electric field) generated in the metal layer 30 due to this anomalous Nernst effect is the same as that due to the spin Seebeck effect. Therefore, in reality, the electromotive force output from the metal layer 30 in the structure of FIG. 1 is the sum of a component due to the spin Seebeck effect and a component due to the anomalous Nernst effect.

In FIG. 1, the radiation source 40 is connected to the lower side of the substrate 10 (negative side in the z direction), but conversely, the radiation source 40 may be connected to the upper side of the metal layer 30 (positive side in the z direction). . In this case, since the direction of the temperature gradient is opposite to that in FIG. 1, if the direction of the applied magnetic field is the same as in FIG. The direction of power is reversed. Moreover, in this case, the first electrode 31 and the second electrode 32 are provided between the metal layer 30 and the radiation source 40.

However, if the radiation source 40 is provided below the substrate 10, the radiation emitted from the radiation source 40 is absorbed by the substrate 10, so that it is suppressed from directly reaching the ferromagnetic insulating layer 20. This is particularly preferred since a temperature gradient ΔT is generated by the substrate 10 that has absorbed this radiation.

As mentioned above, YIG, which is the material used for the ferromagnetic insulating layer 20, is a soft magnetic material, and its coercive force and residual magnetization are very small. Magnetic field application layers 51 and 52 are used to generate H. On the other hand, the spin Seebeck effect as described above occurs even if the ferromagnetic insulating layer 20 is made of a hard magnetic material. In this case, the residual magnetization when the externally applied magnetic field becomes zero can be increased, and the strength of the magnetic field H in FIG. 1 can be maintained by the residual magnetization. Therefore, when the ferromagnetic insulating layer 20 is made of a hard magnetic material, the magnetic field application layers 51 and 52 are unnecessary if a magnetic field as shown in FIG. 1 is applied to the nuclear battery 1 in advance. .

In order to investigate the characteristics of this nuclear power cell 1, a laminated structure consisting of only the substrate 10, the ferromagnetic insulating layer 20, and the metal layer 30 was formed, excluding the magnetic field application layers 51 and 52 and the radiation source 40 in FIG. A temperature gradient (temperature difference ΔT) and a magnetic field H were applied in the x direction from the outside to measure the potential difference (output voltage V0) on both sides of the metal layer 30 in the y direction. Here, GGG with a thickness of 1 mm was used as the substrate 10, YIG with a thickness of 200 nm as the ferromagnetic insulating layer 20, Pt with a thickness of 10 nm as the metal layer 30, and ΔT=8K. FIG. 2 shows the results of measuring the dependence of the output voltage V0 on the magnetic field H. Here, the magnetic field H is scanned on both positive and negative sides, and when the magnetic field H is near zero, a certain residual magnetization in the ferromagnetic insulating layer 20 becomes a magnetic field in the x direction in FIG. 1, so hysteresis occurs depending on the direction of the residual magnetization. ing. The output voltage V0 of the nuclear battery 1 having this configuration has a saturation value on the positive side and negative side of the magnetic field H in FIG. 2, and is about 20 μV.

In addition, we irradiated γ-rays, which have the greatest effect as radiation, in the z direction in Figure 1 as described above, and measured the ΔT dependence of the output voltage (saturation value) as described above for each γ-ray dose (exposure amount). was measured. ⁶⁰ Co was used as the γ-ray source, and the maximum exposure dose was about 1 MGy.

Furthermore, three types of irradiation environments were selected: (1) room temperature and dry atmosphere, (2) high temperature (150°C) and dry atmosphere, and (3) high temperature (150°C) and steam atmosphere. FIG. 3(a) shows the ΔT dependence of the output voltage V0 before irradiation with γ-rays (a), and the same characteristics (b) after 0.86 MGy irradiation under the environment of (2), respectively. There is no significant difference between these, and γ-ray irradiation of about 1 MGy under the environment (2) does not cause the deterioration of the characteristics of the nuclear battery 1 described above. Similar results were obtained under the environment (1). Further, the output voltage in this case has high linearity with respect to ΔT.

On the other hand, in case (3), the output voltage slightly deteriorated as the exposure amount increased. Figure 4(a) shows the ΔT dependence of the output voltage for each exposure dose in this case, and Figure 4(b) shows the exposure dose dependence of the temperature coefficient (proportionality coefficient (V/K) in Figure 4(a)). Each shows its gender. Compared to (1) and (2) above, characteristic deterioration is observed due to γ-ray irradiation, but the deterioration is to the extent that the output voltage is halved at about 1 MGy. For this reason, the nuclear battery 1 described above has high gamma ray resistance and does not require a heavy metal layer for shielding gamma rays. Therefore, by using a plurality of types of radiation sources with long half-lives as described above as the radiation source 40, it is possible to obtain a compact nuclear battery 1 with a long life.

As shown in FIG. 2 and other figures, the output voltage of this nuclear battery 1 is about 10 ⁻⁶ V, which is smaller than other commonly used batteries. However, as shown in Fig. 1, the output voltage of this nuclear battery 1 is extracted in the in-plane direction due to the temperature difference in the thickness direction, so a plurality of nuclear batteries 1 are connected in series to form a new nuclear battery system, and each By applying a temperature difference in the thickness direction, a large output voltage can be obtained.

FIG. 5(a) shows a nuclear battery system 2 that is a first example of such a configuration. In this case, n nuclear batteries 1 are arranged horizontally in the figure on a support substrate (support base) 100, and in each nuclear battery 1, the magnetic field H by the magnetic field application layers 51 and 52 is applied downward in the figure. The temperature gradient ΔT caused by the radiation source 40 is applied in the direction perpendicular to the plane of the paper. At this time, since the direction of the magnetic field H is the same in all nuclear batteries 1, the strength of the magnetic field H is maintained uniformly high within the plane. Moreover, since the temperature gradient ΔT is also uniformly applied throughout the plane, each nuclear battery 1 can obtain a stable output. In this case, if each nuclear battery 1 is connected in series, an output voltage of n×V0 can be obtained, assuming that the output voltage of a single nuclear battery 1 is V0. This allows a high output voltage to be obtained. Similarly, the output voltage can be further increased by arranging such an array of nuclear batteries 1 in parallel also in the vertical direction in FIG. 5(a) and connecting the outputs of the two-dimensional array in series.

Further, as shown in FIG. 5(b) as a nuclear battery system 3 which is a modified example (second example), a nuclear battery 1 is mounted on the outer peripheral surface of a cylindrical support base 110 in the same manner as in FIG. 5(a). Nuclear cells 3 can be arranged on the circumference. Here, two rows of arrays are formed in the vertical direction as described above, but the number of arrays in the vertical direction can also be increased.

Furthermore, in the nuclear battery system of FIGS. 5A and 5B, the radiation source 40 in each nuclear battery 1 may not be provided, and instead, the support substrate 100 and the support base 110 may be configured with the radiation source 40. Since radiation is emitted from the radiation source 40 in all directions, a high output voltage can be obtained even with this configuration. In this case, the radiation source 40 can be substantially omitted in each nuclear battery 1 used in the structure of FIG. FIG. 6 is a lateral cross-sectional view in FIG. 5(a) showing the structure of the nuclear battery system 4 having such a structure. In FIG. 6, the substrate 10 may also be used in common.

In the above example, the direction of the magnetic field H, the direction of the temperature gradient ΔT, and the direction in which the first and second electrodes are formed (direction in which the output voltage is extracted) are assumed to be orthogonal to each other. They do not need to be strictly orthogonal, and the relationship between them may be shifted from orthogonal depending on the element configuration. That is, these directions may intersect with each other as long as a sufficient output voltage can be obtained.

Further, the materials constituting the substrate, the ferromagnetic layer, and the metal layer can be appropriately set other than the above-mentioned examples.
Optical elements other than the two mirrors may be provided as appropriate.

1 Nuclear cells 2 to 4 Nuclear cell system 5 Thermoelectric conversion element 10 Substrate 20 Ferromagnetic insulating layer (ferromagnetic layer)
30 Metal layer 31 First electrode 32 Second electrode 40 Radiation sources 51, 52 Magnetic field application layer 100 Support substrate (support base)
110 Support base

Claims (8)

A nuclear battery that combines a radiation source that constantly emits radiation and a thermoelectric conversion element that generates an electromotive force between a first electrode and a second electrode due to a temperature gradient generated by the radiation,
The thermoelectric conversion element is
a ferromagnetic layer formed on a substrate and having a magnetic field in an in-plane direction;
It is made of a metal material that exhibits a reverse spin Hall effect, is formed on the ferromagnetic layer, and is located at a location where the first electrode and the second electrode are spaced apart in the in-plane direction and in the direction intersecting the magnetic field. A formed metal layer with a thickness of 50 nm or less,
Equipped with
The radiation source that emits a neutron beam is used as the radiation,
The radiation source is connected to the thermoelectric conversion element so as to generate the temperature gradient in the thickness direction of the ferromagnetic layer,
A nuclear battery, wherein the substrate is made of gallium gadolinium garnet (GGG) and coated with boron (B) or cadmium (Cd) . 2. A magnetic field applying layer that applies the magnetic field to the ferromagnetic layer and the metal layer is connected to an end of the ferromagnetic layer and the metal layer in the in-plane direction. nuclear battery. 3. The nuclear cell according to claim 2 , wherein the ferromagnetic layer is made of yttrium-iron-garnet (YIG) or YIG doped with gallium (Ga). 4. The metal layer according to claim 1 , wherein the metal layer contains platinum (Pt), gold (Au), niobium (Nb), nickel (Ni), or stainless steel. Nuclear battery. 5. The nuclear power cell according to claim 1 , wherein the radiation source is connected to a side of the substrate opposite to the side on which the ferromagnetic layer is formed. The nuclear battery according to any one of claims 1 to 5 , wherein the magnetic field in each is in a common direction, and the first electrode and the second electrode in each are on a common side. A nuclear power battery system characterized in that a plurality of batteries are arranged and connected in series and formed on a support base. The support base has a substantially cylindrical shape,
7. The nuclear power battery system according to claim 6 , wherein a plurality of said nuclear batteries are arranged along the circumferential direction of said substantially cylindrical outer peripheral surface. The nuclear battery system according to claim 6 or 7 , wherein the support base is made of a material that constantly emits the radiation, and the support base also serves as the radiation source in each of the nuclear batteries. .

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