Method for producing a nuclear battery cell

Abstract

The invention relates to a method for producing a nuclear battery cell (1) for generating electric energy from the radiation energy emitted by a radionuclide (2), having the steps of: providing mechanical and / or electric operating components (27), in particular at least one electrode (15, 15A, 15B) and / or a photodiode (23); assembling the mechanical and / or electric operating components (27) within a battery cell housing (3) of the nuclear battery cell (1); filling a radionuclide receiving chamber of the battery cell housing (3) in the assembled state of the mechanical and / or electric operating components (27) with the radionuclide (2) through at least one radionuclide inlet opening (5) of the battery cell housing (3); and closing the at least one radionuclide inlet opening (5) of the battery cell housing (3) in order to obtain the nuclear battery cell (1).

Description

[0001] Process for producing a radionuclide battery cell

[0002] The invention relates to a method for producing a radionuclide battery cell for generating electrical energy from emitted radiation energy of a radionuclide.

[0003] Radionuclide batteries are energy sources that convert the radiation energy from the spontaneous nuclear decay of a radionuclide into electrical energy. Compared to the energy density of conventional (chemical) batteries, the energy density of radionuclide batteries is up to two orders of magnitude higher, which makes radionuclide batteries particularly suitable for applications that require a supply over a very long period of time. One area of ​​application is space, for example. Various principles for using radiation energy are known, which can be divided into thermal conversions and non-thermal conversions. For example, the resulting heat can be absorbed by a thermocouple. Alternatively, semiconductors can be used, for example, in which electron-hole pairs are generated due to the incident radiation from the radionuclide, which in turn generate an electric current.Beta-voltaic batteries, which use beta radiation, and alpha-voltaic batteries, which use alpha radiation, are particularly common. Another possibility for the indirect use of radioactive radiation is to convert the radiation into photons using a luminescent material and then use the resulting photons to generate electrical energy.

[0004] For example, US 2018 / 0372891 A1 shows various embodiments of a nuclide battery. Radiation from radioactive material can, on the one hand, be converted directly into electrical energy using two electrodes and / or semiconductors. Alternatively, or in parallel, a scintillating layer can be provided, which is excited by the incident radiation and subsequently emits photons. The photons are, in turn, used to generate electrical energy by providing semiconductor structures that absorb the photons. Other radionuclide batteries are known, for example, from CN111755142A and US5008759.

[0005] One difficulty in the manufacture of radionuclide batteries lies in the handling of the radioactive substances. There is always a risk of radioactive contamination and spread of radioactive material. For this reason, strict regulations apply to the handling of these materials and consequently also to the manufacture of radionuclide batteries. Typically, the radioactive material is geometrically arranged centrally in the radionuclide battery, on the one hand to shield the radioactive material as reliably as possible from the outside world and on the other hand to be able to use the greatest possible proportion of the radiation if the radionuclide is surrounded by electrodes, for example. Because of this arrangement, the radionuclide has to be handled and installed during or before the assembly of the other components of the radionuclide battery. This means that further, sometimes complex manufacturing steps are necessary after the radionuclide has been introduced.This makes it difficult to clearly separate the production line into an area without the risk of radioactive radiation and an area with appropriate radiation protection measures. This entails a higher risk potential, which necessitates complex safety regulations and has a detrimental impact on production.

[0006] Another disadvantage of radionuclide batteries compared to conventional batteries, such as lithium batteries, is that radionuclide batteries are not rechargeable. Radioactive decay is an irreversible process, so energy cannot be introduced and stored in the radionuclide battery. Once the radionuclide is used up or its activity has fallen below a certain threshold, radionuclide batteries are typically no longer usable.

[0007] A further complication is material fatigue of the radionuclide battery components. Radioactive radiation, for example, can cause a drop in the efficiency of a semiconductor. Therefore, prolonged storage of a radionuclide battery prior to use is not advisable. Instead, it is best to manufacture the radionuclide battery as close to use as possible. This places high demands on production and logistics.

[0008] It is therefore an object of the invention to mitigate or eliminate at least some of the disadvantages of the prior art. The aim of the invention is preferably to make the manufacture of the radionuclide battery safer and simpler.

[0009] The object is achieved by a method according to claim 1. The method comprises at least the following steps:

[0010] Providing mechanical and / or electrical operating components, in particular at least one electrode and / or one photodiode;

[0011] Assembling the mechanical and / or electrical operating components within a battery cell housing of the radionuclide battery cell;

[0012] Filling a radionuclide receiving space of the battery cell housing in the assembled state of the mechanical and / or electrical operating components with the radionuclide through at least one inlet opening of the battery cell housing; and

[0013] Closing at least one inlet opening of the battery cell housing to receive the radionuclide battery cell.

[0014] The object is also achieved by a radionuclide battery cell according to claim 10. The radionuclide battery cell has at least: mechanical and / or electrical operating components, in particular at least one electrode and / or one photodiode, a battery cell housing in which the mechanical and / or electrical operating components are assembled, wherein the battery cell housing has a radionuclide receiving space in which the radionuclide is arranged, wherein the battery cell housing has at least one radionuclide inlet opening for filling the radionuclide receiving space of the battery cell housing with the radionuclide in the assembled state of the mechanical and / or electrical operating components. The battery cell housing preferably forms the outer casing of the radionuclide battery cell. The dimensions of the battery cell housing thus determine the external dimensions of the radionuclide battery cell.The battery cell housing ensures the mechanical stability of the radionuclide battery cell and protects the interior of the radionuclide battery cell from external influences such as mechanical stress or atmospheric humidity. At the same time, the battery cell housing protects the environment of the radionuclide battery cell from radioactive radiation. For this purpose, the battery cell housing can enclose the radionuclide in a substantially radiation-tight manner, in particular also in a substantially gas-tight manner. The radionuclide can, for example, 3 H, 10 Be , 32 Si , 40 K, 90 Sir, 137 Cs, 144 Nd, 2O4 T1, 232 Th, 241 On, 63 No, 90Y. These I isotopes have little gamma emission, which makes them particularly suitable for use in radionuclide battery cells. The half-life of the radionuclide can be between 1 second (s) and 14 billion years, preferably between 10 and 300 years. The radionuclide can be metallic or oxide, either in gaseous, liquid or solid, granular form. The battery cell casing can be made from a metal, preferably aluminum. For example, the battery cell casing can be made from a single piece to ensure high stability.

[0015] The mechanical and / or electrical operating components of the radionuclide battery cell vary depending on the type of radionuclide battery cell.

[0016] In one embodiment, one or more electrodes can be provided as the operating component(s), which absorb released radioactive radiation, whereby an electrical voltage can be generated. The electrodes can consist of a semiconducting material in which incident radioactive radiation can generate electron-hole pairs. For example, II IV semiconductors or quantum dot cells can be used, which suffer relatively little damage from incident radioactive radiation. In a further embodiment, radioluminescent material, for example in the form of a layer, can be provided as the operating component. The radioluminescent material can absorb incident radiation and subsequently release photons.In addition, a photosensitive layer, in particular a photodiode, can be provided which can absorb the photons emitted by the radioluminescent layer and convert them into electrical energy. For example, II IV semiconductors or quantum dot cells can be used in the photodiode. The photodiode can, for example, be a Grätzel cell, preferably in a bifacial transparent design. The radioluminescent material can, for example, be mixed with the radionuclide and introduced into the radionuclide receiving space. Alternatively, the radioluminescent material can be applied directly to a photodiode. The photodiode with a layer of radioluminescent material can, for example, be rolled up, wherein spacers can be arranged on the photodiodes, by means of which spacers a volume is defined within the rolled up photodiode.It is advantageous if radionuclide is arranged in this volume. Furthermore, the mechanical and / or electrical operating components comprise electrical lines with which the radionuclide battery cell can be connected, for example, to a load. Separating structures can be provided that separate individual operating components from one another.

[0017] In a further embodiment, a thermocouple can be provided as the operating component, which converts the heat released by the radionuclide into an electrical voltage. For example, a motor, in particular a Sterling motor, can be provided, which can be driven by the released heat and can convert the heat into electrical energy.

[0018] Depending on the design of the radionuclide battery cell, different mechanical and / or electrical operating components can be provided, which are assembled within the battery cell housing. The manufacture, provision, and assembly of the mechanical and / or electrical operating components and the battery cell housing can take place without radiation protection measures, since none of these components come into contact with radionuclide up to this point.

[0019] According to the invention, the battery cell housing has a radionuclide inlet opening which is connected to the radionuclide receiving space. The radionuclide inlet opening can be a through-bore of the battery cell housing. The cross-section of the radionuclide inlet opening can be round, in particular circular, or for example rectangular, in particular square. The radionuclide inlet opening can have a diameter or a diagonal in cross-section of, for example, 0.3 millimeters (mm) to 50 mm. The cross-sectional area of ​​the radionuclide inlet opening can be significantly smaller than the outer surface of the battery cell housing on which the radionuclide inlet opening is arranged. The radionuclide inlet opening may, for example, have a diameter corresponding to 1% or up to 10% of the diagonal of a circular outer surface of the battery cell casing on which the radionuclide inlet opening is arranged.The radionuclide receiving space can, for example, be a tank separate from the battery cell housing. Alternatively, the radionuclide receiving space can be delimited by the battery cell housing. For example, the mechanical and / or electrical operating components can be in direct contact with the radionuclide. For example, a photodiode with a layer of radioluminescent material and spacers can be provided, which is rolled up or folded and assembled in the battery cell housing. In this design, the spacers can be used to define a volume between the layers of photodiodes, into which volume the radionuclide can be introduced. In this case, the radionuclide receiving space is enclosed by the outer walls of the battery cell housing. In this design, the photodiode is also located in the radionuclide receiving space.To obtain the radionuclide battery cell, in the next step the radionuclide receiving space of the battery cell housing is filled with the radionuclide through the radionuclide inlet opening of the battery cell housing, while the mechanical and / or electrical operating components are already in an assembled state. The radionuclide can be solid or granular, liquid or gaseous. In the next step the radionuclide inlet opening is closed so that the battery cell housing is ready for operation. The closure is preferably essentially gas-tight to ensure reliable shielding of the radionuclide. To ensure greater mechanical operational reliability, especially for use in mobile applications, the radionuclide battery cell can then be arranged within a protective casing. This protective casing can absorb mechanical shocks and improve safety.Depending on the design, several radionuclide battery cells can be interconnected to form a radionuclide battery. Alternatively, a single radionuclide battery cell can be used as a radionuclide battery. Since the radionuclide is only added or introduced after the mechanical and / or electrical operating components have been assembled, it is particularly easy to complete the radionuclide battery cell shortly before use. This optimizes the service life of the radionuclide battery cell with regard to its application. Furthermore, a clear separation of the production line into an area without the risk of radioactive radiation and an area with appropriate radiation protection measures is possible.

[0020] Depending on the design, the radionuclide can be removed from the radionuclide battery cell once its activity has fallen below a certain threshold, and a radionuclide with a higher activity can be added. In this design, the radionuclide battery cell is refillable. To do so, the radionuclide inlet can be opened, and the radionuclide can be removed through the radionuclide inlet. In the next step, radionuclide can be introduced through the radionuclide inlet, and the radionuclide inlet can be closed again.

[0021] Preferably, a closure element is attached to the inlet opening to close the inlet opening. The closure element can, for example, be inserted into the inlet opening in a form-fitting manner. The closure element can be a plate that covers the inlet opening. The closure element and the battery cell housing can be made of the same material. In a preferred embodiment, the closure element can be connected to the battery cell housing via a permanent connection, in particular a joint, for example a welded or adhesive connection. By means of a permanent connection, the interior of the radionuclide battery, in particular the radionuclide, can be particularly reliably shielded from the environment.

[0022] Alternatively, the closure element can be connected to the battery cell housing via a detachable connection, in particular a screw connection or a clamp connection. A detachable connection is particularly advantageous if the radionuclide is to be replaced as soon as the activity of the radionuclide in the radionuclide battery cell falls below a limit or has reached a certain age.

[0023] In a preferred embodiment, at least one membrane is arranged at the radionuclide inlet opening before the radionuclide is introduced. An injection element, in particular a cannula, is then guided through the membrane and finally the radionuclide is introduced into the radionuclide receiving space of the battery cell housing via the injection element. The use of a membrane is particularly advantageous when the radionuclide is in liquid form, since the membrane can prevent uncontrolled or unintentional leakage of liquids. Introducing the radionuclide by means of a cannula allows particularly good control over the introduction or filling of the radionuclide. The membrane can also be designed as a double membrane with a further membrane.The double membrane is arranged at the radionuclide inlet opening, with an injection element, in particular a cannula, being passed through both membranes of the double membrane. The use of a double membrane is particularly advantageous when the radionuclide is in gaseous form, since this makes it particularly safe to prevent uncontrolled or unintentional escape of gaseous radionuclide. In a preferred variant, a further injection element, such as a further cannula, can be passed through the same membrane or double membrane; air can escape from the radionuclide receiving space through the further injection element and is displaced by the radionuclide introduced via the injection element.

[0024] In a further preferred embodiment, a valve body is arranged at the radionuclide inlet opening prior to filling with the radionuclide. A filling element is then connected to the valve body, and the radionuclide is introduced by means of the filling element through the valve body into the radionuclide receiving space of the battery cell housing. The valve body can, for example, be brought into an open valve position by the intended arrangement of the filling element in order to be able to fill with radionuclide through the valve body. The use of a valve body leads to a particularly safe and reproducible filling process.

[0025] In this embodiment, the valve body is preferably arranged in a closed valve position after the radionuclide receiving chamber has been filled with the radionuclide. The valve body can, for example, be automatically or independently moved into a closed valve position when the filling element is released or removed from the valve body. In this embodiment, the valve body can only be arranged in the open valve position as long as the filling element is connected to the valve body.

[0026] In a further preferred embodiment, the radionuclide is introduced through the free, i.e., unsealed, radionuclide inlet opening, wherein the radionuclide is preferably in a solid, particularly granular, or liquid state. For example, the radionuclide can be introduced into the radionuclide battery cell through the free radionuclide inlet opening using a funnel.

[0027] Preferably, the method comprises the following further step:

[0028] Filling an electrolyte receiving space of the battery cell housing with an electrolyte through an electrolyte inlet opening. The use of an electrolyte is particularly advantageous in embodiments in which at least one electrode is provided as the operating component(s). In this embodiment, an electrolyte receiving space can be provided which can receive the electrolyte. The electrolyte receiving space can be identical to the radionuclide receiving space. The electrolyte receiving space can be the radionuclide receiving space, so that the electrolyte is present together with the radionuclide in the same radionuclide receiving space. For this purpose, the electrolyte inlet opening can also be the radionuclide inlet opening, so that the radionuclide and the electrolyte are introduced through the same inlet opening. As described above, a valve body or a membrane can be arranged at the electrolyte inlet opening.The electrolyte can be gaseous, liquid, or granular.

[0029] Preferably, a closure element is provided, with which the electrolyte inlet opening is closed, preferably in a substantially gas-tight manner. The closure element can be designed as described above in connection with the radionuclide inlet opening.

[0030] The battery cell housing can preferably have at least one first air outlet opening to simplify filling with radionuclide. For this purpose, the air outlet opening can be separate and spaced from the radionuclide inlet opening. Air can escape from the radionuclide receiving space through the air outlet opening, which is successively displaced by the introduced radionuclide during filling. The air outlet opening and the radionuclide inlet opening can be identical; for example, a valve body or a membrane can be arranged on both. Depending on whether the introduced radionuclide has a higher or lower density than the air originally present in the radionuclide receiving space, it may be advantageous to rotate the battery cell housing relative to the acceleration due to gravity during filling in such a way that the radionuclide inlet opening is located higher or lower than the air outlet opening.If the radionuclide has a higher density than air, for example, it is advantageous if the air outlet opening is the same height as or higher than the radionuclide inlet opening, since the air is displaced upwards (relative to gravity). In the event that the radionuclide has a lower density than air, it is advantageous to use the i l.

[0031] The air outlet opening should be lower than the radionuclide inlet opening, at the same height or as low as possible.

[0032] In addition, a further closure element can be provided, with which the first air outlet opening is closed, preferably in a substantially gas-tight manner. Like the radionuclide inlet opening, the air outlet opening must also be closed. The further closure element for closing the air outlet opening can be designed in the same way as the closure element for closing the radionuclide inlet opening.

[0033] The battery cell housing can preferably have an electrolyte receiving space in which an electrolyte is arranged, wherein the battery cell housing has at least one electrolyte inlet opening for filling the electrolyte receiving space of the battery cell housing with the electrolyte in the assembled state of the mechanical and / or electrical operating components. If at least one electrode is provided as the operating component, the use of an electrolyte can be advantageous in order to enable a REDOX reaction. For this purpose, an electrolyte receiving space can be provided which can receive the electrolyte. The electrolyte receiving space can be designed identically to the radionuclide receiving space. The electrolyte receiving space can be the radionuclide receiving space, thus the electrolyte can be present together with the radionuclide in the same radionuclide receiving space.

[0034] The following further step is preferably provided: filling a receiving space for radioluminescent material in the battery cell housing with a radioluminescent material through an inlet opening for radioluminescent material. If at least one photodiode is provided as the operating component, the use of radioluminescent material can be advantageous or necessary. For this purpose, a receiving space for radioluminescent material can be provided which can receive the radioluminescent material. The receiving space for radioluminescent material can be designed in the same way as the radionuclide receiving space. The receiving space for radioluminescent material can be the radionuclide receiving space, so the radioluminescent material can be present together with the radionuclide in the radionuclide receiving space. This arrangement is particularly advantageous because the radionuclide can be surrounded by radioluminescent material ormixed with radioluminescent material. This can increase the yield of photons. The inlet opening for radioluminescent material can be designed in the same way as the radionuclide inlet opening; in particular, both can be designed identically; for example, a valve body or a membrane can be arranged on both.

[0035] The present invention is further explained with reference to embodiments shown in the drawings, to which it is not intended, however, to be limited.

[0036] Fig. 1A-D show a schematic representation of a radionuclide battery cell according to the invention, which can be filled with radionuclide by means of a valve body.

[0037] Fig. 2A-D show a schematic representation of another radionuclide battery cell according to the invention, which can be filled with radionuclide by means of an in ection element and a membrane.

[0038] Fig . 3 shows a schematic representation of a radionuclide battery cell which can be filled with radionuclide and an electrolyte .

[0039] Fig. 4A-C show sections of a battery cell housing of the radionuclide battery cell according to the invention.

[0040] Fig. 5 shows a schematic representation of another radionuclide battery cell according to the invention with radio-luminescent material and a photodiode.

[0041] Fig. 6A shows schematically a layer structure of a photodiode of the radionuclide battery cell according to the invention with a layer of radio-luminescent material and spacers in a rolled-up state.

[0042] Fig. 6B shows schematically the layer structure from Fig. 6A in a folded state. Fig. 1A shows a radionuclide battery cell 1 for generating electrical energy from emitted radiation energy of a radionuclide 2 (see Fig. 1D). The radionuclide battery cell 1 has a cylindrical battery cell housing 3 with two valve bodies 4, which are arranged at a radionuclide inlet opening 5 and an air outlet opening 6, respectively. The radionuclide battery cell 1 also has two electrical connections 7, to which the radionuclide battery cell 1 can be electrically connected. Figure 1B shows a plan view of the radionuclide battery cell 1 shown in Fig. 1A.

[0043] Fig. 1C shows a cross-section through the battery cell housing 3 before filling with the radionuclide 2. The radionuclide battery cell 1 has mechanical and / or electrical operating components 27 (see Figure 3) within the battery cell housing 3, which are already assembled according to Fig. 1C. For the sake of clarity, the mechanical and / or electrical operating components 27 are not shown in Figs. 1A to 1D. Provided in the battery cell housing 3 is a radionuclide receiving space 8, into which the radionuclide 2 is introduced. The radionuclide receiving space 8 can be enclosed by a housing. This housing can be made of a material adapted to the type of radiation of the radionuclide 2. For beta radiation, a radiation-resistant, for example transparent, plastic container enclosing the radionuclide receiving space 8 can be provided.The plastic container can be made of polyimide, for example, with wall thicknesses of, for example, 100 pm to 1 mm, preferably 300 pm to 0.7 mm. Alternatively, the housing can be made of glass, for example borosilicate glass, with wall thicknesses of 50 pm to 4 mm, in particular 300 pm to 3 mm, preferably 500 pm to 2 mm. The housing of the radionuclide receiving space 8 can be made of aluminum, for example. For gaseous radionuclides 2, the radionuclide receiving space 8 can be enclosed by a tank that is essentially gas-tight and essentially transparent to the respective type of radiation emitted, and which can be fastened inside the battery cell housing 3. The gas diffusion properties with respect to the tightness of the material from which the tank is made should be in the order of magnitude from three times to at least once the half-life of the radionuclide.If the half-life is, for example, 12 years, gaseous radionuclide should not diffuse through the tank within at least 12 to approximately 36 years. Glass or plastic can be used for beta radiation. Since there is no suitable material that is transparent to alpha radiation, an alpha-emitting radionuclide 2 can, for example, be arranged together with a radioluminescent material 22 (see Fig. 5) in the radionuclide receiving space 8. This arrangement can also be favorable for beta-emitting radionuclides 2.

[0044] 1A to 1D, the valve body 4 is arranged at the radionuclide inlet opening 5. According to Fig. 1C, a filling element 9 is connected to the valve body 4. By means of the filling element 9, the radionuclide 2 is introduced into the radionuclide receiving space 8 through the valve body 4 arranged in the radionuclide inlet opening 5. The battery cell housing 3 has the first air outlet opening 6, at which one of the valve bodies 4 is arranged, which is connected to a further filling element 9. By connecting the valve bodies 4 to the filling elements 9, the valve bodies 4 are moved from a closed position to an open position. Accordingly, the valve bodies 4 can be moved into a closed position by pulling off or separating the filling elements 9 from the valve bodies 4.The air outlet opening 6 simplifies filling with radionuclide 2, since the air displaced by the radionuclide 2 can escape through the air outlet opening 6. In the embodiment shown, the air outlet opening 6 and the radionuclide inlet opening 5 are used simultaneously. After filling with the radionuclide 2, the filling elements 9 are separated from the valve bodies 4, whereby the valve bodies 4 are in a closed position (cf. Fig. 1D). This closes both the radionuclide inlet opening 5 and the air outlet opening 6. Due to the arrangement of the valve bodies 4 and the closed position of the valve bodies 4, the first air outlet opening 6 and the radionuclide inlet opening 5 are essentially sealed gas-tight.Further mechanical and / or electrical operating components 27 are not shown in this embodiment, since the invention is independent of the type of radionuclide battery cell 1 and therefore the design can vary. For example, an electrode 15 (see Figure 3) and / or a photodiode (see Figure 5 or 6) can be assembled inside the battery cell housing 3 while the radionuclide 2 is being filled in.

[0045] Fig. 1D shows a cross-section through the radionuclide battery cell 1 from Fig. 1A. At this point in time, the radionuclide 2 has already been filled into the radionuclide receiving space 8 and the filling elements 9 have been separated from the valve bodies 4. To securely close the radionuclide inlet opening, a closure element 11 is arranged on each of the two valve bodies 4. The closure elements 11 are connected to the valve bodies 4 via permanent connections, in particular via adhesive connections. Alternatively, the closure elements 11 can be welded to the valve bodies 4. Furthermore, detachable connections, for example screw connections or clamp connections, can be provided between the closure elements 11 and the valve bodies 4.

[0046] In an alternative embodiment (not shown), the radionuclide 2 can be introduced, for example, by means of a funnel through the exposed radionuclide inlet opening 5. In this embodiment, the radionuclide 2 is preferably in the solid, particularly granular, state, or in the liquid state.

[0047] Fig. 2A shows a further embodiment of the radionuclide battery cell 1, in which closure elements 11 are arranged at the radionuclide inlet opening 5 and the air outlet opening 6. In the embodiment shown, the closure elements 11 can be connected to the battery cell housing 3 via adhesive bonds. Fig. 2B shows a plan view of the radionuclide battery cell 1 from Fig. 2A.

[0048] Fig. 2C shows a cross-section through the battery cell housing 3 from Figure 2A before filling with radionuclide 2. The mechanical and / or electrical operating components 27 (not shown, see Figure 3) within the battery cell housing 3 of the radionuclide battery cell 1 have already been assembled. A radionuclide receiving space 8 is provided in the battery cell housing 3, into which the radionuclide 2 is introduced. Two membranes 12 are arranged at the radionuclide inlet opening 5, which membranes together form a double membrane 13 through which an injection element 14, here a cannula, is guided. By means of the injection element 14, the radionuclide 2 is introduced through the double membrane 13 into the radionuclide receiving space 8 of the battery cell housing 3. The battery cell housing 3 has a first air outlet opening 6, at which a double membrane 13 is also arranged.The air outlet opening 6 simplifies filling with radionuclide 2 because the air displaced by the radionuclide 2 can escape through the air outlet opening 6. For this purpose, a further injection element 14, here again a cannula, is guided through the membrane 13. The air outlet opening 6 and the radionuclide inlet opening 5 are used simultaneously. After the radionuclide 2 has been filled, the injection elements 14 are removed. The radionuclide inlet opening 5 and the air outlet opening 6 are closed by means of the closure elements 11. Further mechanical and / or electrical operating components 27 are provided in this embodiment as in the embodiment of Fig. 1A to Fig. ID is not shown, since the invention is independent of the type of radionuclide battery cell and therefore the design can vary. For example, an electrode 15 (see Fig. 3) and / or a photodiode 23 (see Fig. 5) can be provided.

[0049] Fig. 2D shows a cross-section of the radionuclide battery cell 1 shown in Fig. 2A. In the state shown, the radionuclide 2 has already been filled into the radionuclide receiving space 8, and the closure elements 11 have been glued into the air outlet opening 6 and the radionuclide inlet opening 5 to seal the battery cell housing 3 in a substantially gas-tight manner. The closure elements 11 are connected to the battery cell housing 3 via non-detachable connections, in particular via adhesive connections.

[0050] Fig. 3 shows a battery cell housing 3 with assembled mechanical and / or electrical operating components 27, which can be manufactured using one of the methods described above. The battery cell housing 3 can, for example, have a side length of 10 mm to 1000 mm, in particular of 20 mm to 300 mm, preferably of 30 mm to 200 mm, particularly preferably 80 mm to 140 mm. Alternatively, the battery cell housing can be cylindrical, spherical or designed as a polyhedron. Two electrodes 15A, 15B are provided, each of which is arranged directly on the battery cell housing 3. The radionuclide receiving space 8 is delimited by the electrode 15A, a separating structure 16 and the battery cell housing 3. Thus, the electrode 15A, which may be the cathode, is in direct contact with the radionuclide 2 in the radionuclide battery cell 1.Effects such as diffusion and / or corrosion can be taken into account when selecting the materials in order to avoid chemical changes or damage to the electrode 15A. The separation structure 16 is preferably used together with liquid and / or gaseous radionuclides 2, wherein in this case beta emitters are primarily considered as the radionuclide 2, since the separation structure 16 blocks alpha radiation. Beta radiation, on the other hand, also penetrates thin layers, wherein the thickness of the separation structure 16 can be in a range from 10 nm to 1 mm, in particular 50 nm to 300 pm, preferably between 300 nm and 100 pm. Polymers and thin glass layers, but also metallized polymer films and graphene layers can be used as materials for the separation structure 16.The radionuclide receiving space 8 can be filled with radionuclide 2 during production via the radionuclide inlet opening 5, wherein air can escape via the first air outlet opening 6. In addition, an electrolyte receiving space 17 is delimited by the electrode 15B, which can be the anode, the separating structure 16, and the battery cell housing 3. An electrolyte (not shown) is introduced into the electrolyte receiving space 17 via an electrolyte inlet opening 18. This step, like the filling with radionuclide 2, takes place after the mechanical and / or electrical operating components 27 of the radionuclide battery cell 1 have been assembled. Preferably, the electrolyte receiving chamber 17 is filled with the electrolyte and the electrolyte inlet opening 18 is closed before the radionuclide receiving chamber 8 is filled with radionuclide 2.Air can escape from the electrolyte receiving chamber 17 via a second air outlet opening 19 and is displaced by the introduced electrolyte. The radionuclide inlet opening 5, the air outlet opening 6, the electrolyte inlet opening 18 and the second air outlet opening 19 are each closed after filling with radionuclide or with the electrolyte. At least the electrode 15B can have structural elements 21 that increase the surface of the electrode 15B and thus the probability of interaction with radioactive radiation released by the radionuclide 2. The structural elements 21 can be or have, for example, nano- or microstructure elements that can be applied, for example, using nanotechnological deposition processes. For example, nanotubes can be used, which can be made of TiO2.The use of nanostructures is particularly advantageous in connection with beta emitters in order to increase the efficiency of the radionuclide battery cell 1. The structural elements 21 are surrounded by the electrolyte in the radionuclide battery cell 1 or are located in the electrolyte receiving space 17 and form an intimate connection to the REDOX process of electron conduction in the radionuclide battery cell 1. The electrolyte can contain iodine or potassium iodide, for example, and can accelerate the regeneration of the electrode 15B after the incidence of radioactive radiation and thus improve the efficiency of the conversion of radiation into electrical current. In this exemplary embodiment, the radionuclide inlet opening 5, the air outlet opening 6, the electrolyte inlet opening 18 and the second air outlet opening 19 are exposed; The radionuclide 2 and the electrolyte can be introduced using a funnel, for example.The height of the electrolyte inlet opening 18 can differ from the height of the second air outlet opening 19. If the electrolyte has a higher density than air, the electrolyte collects (relative to the acceleration due to gravity) below the air in the electrolyte receiving space 17. It is therefore advantageous if the second air outlet opening 19 is arranged above the electrolyte inlet opening 18. It is particularly advantageous if the second air outlet opening 19 is arranged as high as possible at the highest point of the electrolyte receiving space 17 in order to be able to fill the electrolyte receiving space 17 as completely as possible with electrolyte. The radionuclide 2 and / or the electrolyte can be filled in the same way as in the embodiments of Fig. 1A to Fig. 1D or Fig. 2A to Fig. 2D can be filled.For example, valve bodies 4 (see Fig. 1A-D) or membranes 12 (see Fig. 2A-D) can be arranged at the radionuclide inlet opening 5, the air outlet opening 6, the electrolyte inlet opening 18, and / or the second air outlet opening 19. In this exemplary embodiment, the mechanical and / or electrical operating components 27 comprise two electrodes 15A and 15B, the structural elements 21, and the separating structure 16, which are assembled before filling with the electrolyte and the radionuclide 2. The radionuclide 2 is freely filled into the radionuclide receiving space 8. For this purpose, the radionuclide 2 is in solid or granular, liquid, or gaseous form.

[0051] Fig. 4A shows two sections of a battery cell housing 3 with a radionuclide inlet opening 5 and a first air outlet opening 6, each sealed by a double membrane 13. An injection element 14, which is a cannula here, is inserted through each of the double membranes 13. Radionuclide 2 is introduced through the radionuclide inlet opening 5, while simultaneously air is removed through the first air outlet opening 6. The same volume of air is removed as is introduced with radionuclide 2 to accelerate the filling process.

[0052] Fig. 4B shows a section of a battery cell housing 3, showing the radionuclide inlet opening 5. The double membrane 13, through which two injection elements 14A, 14B pass, is arranged at the radionuclide inlet opening 5. One injection element 14A is used to introduce radionuclide 2 through the double membrane 13 into the radionuclide receiving space 8. The other injection element 14B is used to remove air displaced by the radionuclide 2 from the radionuclide receiving space 8. This eliminates the need for a separate air outlet opening 6.

[0053] Fig. 4C shows a detailed view of an embodiment of the radionuclide inlet opening 5 in the nuclide battery housing 3, which was closed with the closure element 11 after filling the radionuclide receiving space 8.

[0054] Fig. 5 shows an embodiment of the radionuclide battery cell 1 with the radionuclide receiving space 8, a layer of radioluminescent material 22, and a photodiode 23. The radioluminescent material 22 is excited by the radiation of the radionuclide 2, whereupon photons are emitted. The emitted photons can preferably have a wavelength in a range from 1 nm to 10 pm, in particular 200 nm to 2000 nm, preferably 200 nm to 900 nm. The photodiode 23 can, for example, comprise silicon (Si), crystalline silicon (c-Si), monocrystalline silicon (m-Si), GaAs, or perovskite. The photodiode 23 can alternatively be an organic solar cell or a DSSC ("dye-sensitized solar cell"). The central emitted wavelength may coincide with a sensitivity maximum of the photodiode 23 in order to increase the efficiency of the radionuclide battery cell.The photons are absorbed by the photodiode 23, causing an electric current. No radionuclide inlet opening 5 is visible in this figure; see Figures 1 to 4 for details.

[0055] The conversion of incoming radioactive radiation into photons by the radioluminescent material 22 is achieved through the use of rare earth oxides, such as doped ZnS. The incoming radioactive radiation releases energy, leading to excited states in the radioluminescent material 22 and to a secondary emission of photons. The radioluminescent material 22 is selected such that the wavelengths of the photon emissions spectrally overlap with the sensitivity of the photodiode 23, thus allowing the maximum number of photons to be utilized. The radioluminescent material can comprise earth oxides and phosphorus substances, such as silver-doped ZnS with admixture of green phosphorus or strontium aluminate, in a mass ratio of 100:1 to 1:100, in particular 10:1 and 1:10, preferably 1:4. The radioluminescent material can, for example, be ZnS:Cu or ZnS:Cu:Ag.The radioluminescent material can be tailored to the species of radionuclide 2 or the expected radiation. The yield of photons from the incident radiation can be optimized. For example, the ratio of photons / MeV ("light yield") can be optimized. For each emitted alpha particle from the radionuclide, for example, up to 10 A 5 photons are created.

[0056] Wavelength optimization can be achieved by using quantum dot semiconductors in conjunction with the photodiode 23, whereby the sensitivity is precisely matched to the central wavelength of the emission of the radio-luminescent material 22 by means of quantum dots.

[0057] Fig. 6A shows a photodiode 23 onto which a layer of radioluminescent material 22 has been applied. Spacers 24 are also provided. The spacers 24 are made of a chemically inert and electrically insulating material and are transparent to the photons emitted by the radioluminescent material 22. The spacers 24 can, for example, be honeycomb-shaped or designed as a grid, wherein the radionuclide 2 can be arranged in the free spaces within the spacers 24 and between the spacers 24. As shown in Figure 6A at the bottom right or left, the layer structure 25 can be wound up before it is arranged in the battery cell housing 3. By means of the spacers 24, a volume can be defined between the layers of radioluminescent material 22 and photodiodes 23, into which volume radionuclide 2 can be introduced at a later time.The spacers 24 improve the mechanical and electrical stability of the radionuclide battery cell 1. The spacers 24 enable the stackability or rollability of the photodiode 23, or the foldability. The wound layer structure 25 is arranged in the radionuclide receiving space of the battery cell housing 3. Alternatively, the layer structure 25 can also be arranged folded instead of rolled, as shown in Fig. 6B.

Claims

Claims:

1. A method for producing a radionuclide battery cell (1) for generating electrical energy from emitted radiation energy of a radionuclide (2), comprising the steps: Providing mechanical and / or electrical operating components (27), in particular at least one electrode (15, 15A, 15B) and / or a photodiode (23); Assembling the mechanical and / or electrical operating components (27) within a battery cell housing (3) of the radionuclide battery cell (1); Filling a radionuclide receiving space (8) of the battery cell housing (3) in the assembled state of the mechanical and / or electrical operating components (27) with the radionuclide (2) through a radionuclide inlet opening (5) of the battery cell housing (3); and Closing the at least one radionuclide inlet opening (5) of the battery cell housing (3) in order to obtain the radionuclide battery cell (1).

2. Method according to claim 1, characterized in that in order to close the radionuclide inlet opening (5) a closure element (11) is attached to the radionuclide inlet opening (5).

3. Method according to claim 2, characterized in that the closure element (11) is connected to the battery cell housing (3) via a non-detachable connection, in particular a joining connection, for example a welded or adhesive connection.

4. Method according to claim 2, characterized in that the closure element (11) is connected to the battery cell housing (3) via a detachable connection, in particular a screw connection or a clamp connection.

5. Method according to one of the preceding claims, characterized in that before filling the radionuclide (2) at least one membrane (12) is arranged at the radionuclide inlet opening (5) and then an injection element (14, 14A, 14B), in particular a cannula, is guided through the membrane (12) and finally, the radionuclide (2) is introduced into the radionuclide receiving space (5) of the battery cell housing (3) through the injection element (14, 14A, 14B).

6. Method according to one of claims 1 to 4, characterized in that before filling the radionuclide (2) a valve body (4) is arranged at the radionuclide inlet opening (5), then a filling element (9) is connected to the valve body (4) and the radionuclide (2) is introduced by means of the filling element (9) through the valve body (4) into the radionuclide receiving space (8) of the battery cell housing (3).

7. Method according to claim 6, characterized in that the valve body (4) after filling the radionuclide receiving space (8) with the radionuclide (2) in a closed valve position.

8. Method according to one of claims 1 to 4, characterized in that the radionuclide (2) is filled through the freely present radionuclide inlet opening (5), wherein the radionuclide (2) is preferably in the solid, in particular in the granular state, or in the liquid state.

9. Method according to claim 1, characterized by the further step: Filling an electrolyte receiving space (17) of the battery cell housing (3) with an electrolyte through an electrolyte inlet opening (18).

10. Radionuclide battery cell (1) for generating electrical energy from emitted radiation energy of a radionuclide (2), comprising: mechanical and / or electrical operating components (27), in particular at least one electrode (15, 15A, 15B) and / or a photodiode (23), a battery cell housing (3) in which the mechanical and / or electrical operating components (27) are assembled, wherein the battery cell housing (3) has a radionuclide receiving space (8) in which the radionuclide (2) is arranged, characterized in that the battery cell housing (3) has at least one radionuclide inlet opening (5) for filling the radionuclide receiving space (8) of the battery cell housing (3) with the radionuclide (2) in the assembled state of the mechanical and / or electrical operating components (27).

11. Radionuclide battery cell (1) according to claim 10, characterized by a closure element (1) with which the radionuclide inlet opening (5) is closed, preferably in a substantially gas-tight manner.

12. Radionuclide battery cell (1) according to one of claims 10 or 11, characterized in that the battery cell housing (3) has at least one first air outlet opening (6) in order to simplify filling with radionuclide (2).

13. Radionuclide battery cell (1) according to claim 12, characterized by a further closure element (11) with which the first air outlet opening (6) is closed, preferably in a substantially gas-tight manner.

14. Radionuclide battery cell (1) according to one of claims 10 to 13, characterized in that the battery cell housing (3) has an electrolyte receiving space (17) in which an electrolyte is arranged, wherein the battery cell housing (3) has at least one electrolyte inlet opening (18) for filling the electrolyte receiving space (17) of the battery cell housing (3) with the electrolyte in the assembled state of the mechanical and / or electrical operating components (27).

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