Portable light electricity production device and method of producing electricity

Abstract

A portable electricity production device is disclosed. The devoice comprising: a container comprising: a reservoir comprising hydride salt powder; a selective membrane covering the container and configured to allow an entrance of water molecules into the container and restricts the exit of hydrogen molecules from escaping the container; a first membrane exchange assembly (ME A) electrode attached to an inner side of the selective membrane facing the reservoir; and a outer electrode attached to an outer side of the selective membrane, opposite to the inner electrode, and exposed to the oxygen in the air, wherein the selective membrane is further configured to transfer either protons or hydroxide anions from the inner electrode to the outer electrode.

Description

PORTABLE LIGHT ELECTRICITY PRODUCTION DEVICE AND METHODOF PRODUCING ELECTRICITYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of IL Patent Application No. 298456, filed 21 November 2022, and titled: “PORTABLE LIGHT ELECTRICITY PRODUCTION DEVICE AND METHOD OF PRODUCING ELECTRICITY” which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates generally to portable electricity production devices. More specifically the invention relates to a portable electricity production device based on hydrogen fuel cells.BACKGROUND OF THE INVENTION

[0003] Portable electricity production devices are devices that can produce electricity independently from stored chemical or physical energy. The most commonly used devices are batteries, which convert chemical energy into electricity.

[0004] Many battery chemicals are corrosive, poisonous or both. If leakage occurs, either spontaneously or through accident, the chemicals released may be dangerous. Many types of batteries employ toxic materials such as lead, mercury, and cadmium as an electrode or electrolyte. When each battery reaches the end of life it must be disposed of to prevent environmental damage. Batteries are one form of electronic waste (e-waste). E- waste recycling services recover toxic substances, which can then be used for new batteries. Of the nearly three billion batteries purchased annually in the United States, about 179,000 tons end up in landfills across the country.

[0005] Fuel-cells are electrochemical cells that convert the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.

[0006] In addition to electricity, hydrogen-based fuel-cells produce water vapor and heat, using non-polluting electrodes and membranes, thus regarded as a green energy power source. In order to make fuel-cell green energy packs, there is a need to develop a portable light (low weight) source for hydrogen production that can be integrated into the fuel-cell.SUMMARY OF THE INVENTION

[0007] Some aspects of the invention may be directed to a portable electricity production device, comprising: a container comprising: a reservoir comprising hydride salt powder; a selective membrane covering the container and configured to allow an entrance of water molecules into the container and restricts the exit of hydrogen molecules from escaping the container; a first membrane exchange assembly (MEA) electrode attached to an inner side of the selective membrane facing the reservoir; and a outer electrode attached to an outer side of the selective membrane, opposite to the inner electrode, and exposed to the oxygen in the air, wherein the selective membrane is further configured to transfer either protons or hydroxide anions from the inner electrode to the outer electrode.

[0008] In some embodiments, the selective membrane is an ion conductor. In some embodiments, the hydride salt is configured to react with water to evolve hydrogen gas exothermically. In some embodiments, the hydride salt is selected from: LiH, LiAlH4, NaBH4, NaAlH4, NaH, LiBH4, MgH2, Mg(AlH4)2, Mg(BH4)2, Mg(AlH4)2and any combination thereof.

[0009] In some embodiments, the hydride salt is configured to react with water to evolve hydrogen gas endothermically and wherein the device further comprises a heating element for heating the hydride salt. In some embodiments, the reservoir further comprises a first catalyst configured to accelerate the hydrogen production from the hydride salt. In some embodiments, the first catalysator is selected from: Ru, Co, Cu, Mg, Ni and Fe. In some embodiments, the reservoir further comprises water absorbers.

[0010] In some embodiments, the reservoir is covered by a protective filter configured to allow water molecules to reach the hydride salt and hydrogen molecules to escape towards the inner electrode while maintaining the hydride salt inside the reservoir. In some embodiments, the selective membrane is a proton exchange membrane (PEM) and whereinthe inner electrode is an anode comprising a second catalyst configured to convert hydrogen to protons. In some embodiments, the selective membrane is an anion exchange membrane (AEM) and wherein the inner electrode is a cathode comprising a third catalyst configured to convert hydroxide anions and hydrogen to water and electricity. In some embodiments, the container comprises a flexible expendable material. In some embodiments, the portable electricity production device further comprises a cover, covering at least a portion of the container and constraining the expansion of the container due to the production of hydrogen.

[0011] In some embodiments, the portable electricity production device further comprises 0.01-100 grams of hydride salt powder. In some embodiments, the reservoir containing the hydride salt powder is a replaceable capsule. In some embodiments, the portable electricity production device further comprises a piercing element configured to pierce the replaceable capsule prior to operating the device.

[0012] In some embodiments, the reservoir containing the hydride salt powder is further covered with a breakable cover configured to block the hydride salt powder from the moisture in the air when the device is not operative. In some embodiments, an area of the selective membrane is between 1 cm2to 400 cm2.

[0013] Some additional aspects of the invention may be directed to an airborne vehicle comprising: a propulsion unit powered by one or more electric motors; and one or more portable electricity production devices according to any one of the embodiments of the invention providing electricity to the one or more electric motors. In some embodiments, the container is a balloon configured to expand due to the hydrogen production.

[0014] Some additional aspects of the invention may be directed to a method of producing electricity, comprising: exposing a portable electricity production device to humidity in the air, wherein the device comprises: a container comprising: a reservoir comprising hydride salt powder, a selective membrane covering the container and configured to allow an entrance of water molecules into the container and restrict the exit of hydrogen molecules from escaping the container, a first membrane exchange assembly (MEA) electrode attached to an inner side of the selective membrane facing the reservoir, and a outer electrode attached to an outer side of the selective membrane, opposite to the inner electrode, and exposed to the oxygen in the air wherein the selective membrane is further configured totransfer either protons or hydroxide anions from the inner electrode to the outer electrode; collecting in the container hydrogen produced by a reaction between the humidity and the hydride salt powder, providing the hydrogen to the inner electrode; exposing the outer electrode to the oxygen in the air, producing electricity using a fuel cell formed by the inner electrode, the membrane and the outer electrode.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0016] Fig. 1 is an illustration of a portable electricity production device according to some embodiments of the invention;

[0017] Figs. 2A and 2B are images of portable electricity production devices connected to an electricity consumer with and without a cover, respectively, according to some embodiments of the invention;

[0018] Fig. 3 is an illustration of an airborne platform with a compliant floating component according to some embodiments of the invention;

[0019] Fig. 4 is an illustration of an airborne platform according to some embodiments of the invention; and

[0020] Fig. 5 is a flowchart of a method of producing electricity according to some embodiments of the invention.

[0021] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0022] One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting ofthe invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

[0023] Some aspects of the invention are direct to a light and portable electricity production device, that comprises a controlled hydrogen production source and a fuel-cell for converting the hydrogen to electricity and water vapor. The light and portable electricity production device according to embodiments of the invention may be light in weight, therefore may be included in small to medium size airborne platforms (e.g., 0.5-20 Kg drones, etc.)

[0024] In some embodiments, the controlled hydrogen production source may include a reservoir comprising hydride salt powder that when exposed to the humidity in the air, produces hydrogen and non-polluting products. The released hydrogen reaches with a first electrode of a fuel-cell (Membrane electrode assembly, MEA), which can either be an anode of proton exchange membrane (PEM) of a fuel-cell or an anion exchange membrane (AEM) of a fuel-cell, or any permeable ionic and water conducting to produce electricity and water.

[0025] As used herein, a non-polluting product is a chemical composition or a mixture of chemical compositions that cause little to no pollution. A non-polluting product is a material that can be safely discharged into the environment under the required standards.

[0026] Reference is now made to Fig. 1 which is an illustration of a light portable electricity production device according to some embodiments of the invention. A portable electricity production device 100 may act as a green electricity power source that may replace batteries. Device 100 may provide electricity to various consumers, such as, but not limited to, airborne platforms (e.g., as illustrated in Figs. 2A, 2B, 3, and 4), toys (e.g., toy trains, toy cars, robots, dolls, etc.), electric shavers, and the like.

[0027] Device 100 may include a container 10 comprising a reservoir 20 comprising hydride salt powder 22, a selective membrane 30 covering the container, a first membrane exchange assembly (MEA) electrode 40 attached to an inner side of selective membrane 30 facing the reservoir 20 and a outer electrode 50 attached to an outer side of selective membrane 30, opposite to inner electrode 40.

[0028] In some embodiments, container 10 may be made from a flexible material, an expendable material, or a rigid material. A nonlimiting example, for a rigid container 10 may include a piston or folded structure (harmonica). In some embodiments, container 10 maybe made from any suitable polymer, for example, polypropylene, polyethylene, silicone elastomers and the like. In some embodiments, container 10 may include an entrance for receiving replaceable reservoirs 20, as discussed herein below.

[0029] In some embodiments, reservoir 20 includes a predetermined amount of hydride salt powder 22 which can produce a known amount of hydrogen. In some embodiments, reservoir 20 may include between 0.01 to 100 gr. of hydride salt powder 22, or any value in between, for example, 0.5 gr., 1 gr., 2 gr., 5 gr., 8 gr., 10 gr., 20 gr., 30 gr., 50 gr., 80 gr. and 90 gr.

[0030] In some embodiments, the hydride salt may be selected from lithium hydride (LiH), lithium aluminum hydride (LiAlH4), sodium borohydride (NaBH4), NaAlH4, NaH, LiBH4,MgH2, MgCAlH4)2, Mg(BH4)2, and any combination thereof. The hydride salt may react with water molecules from the humidity in the air to produce hydrogen and a solid product. In some embodiments, the solid product may be non-polluting. Some nonlimiting examples for such reactions may include:

[0031] LiAlH4+ 4H2O LiOH + A1(OH)3+ 4H2

[0032] NaBH4+ (2+x) H2O -> 4H2(g) + NaBO2.xH2O + heatWherein x represents the excess water of hydration in the sodium borate crystal

[0033] LiH + H2O -> LiOH+ H2(g)

[0034] In some embodiments, the hydride salt is configured to react with water to evolve hydrogen gas exothermically. Alternatively, the hydride salt is configured to react with water to evolve hydrogen gas endothermically and therefore, device 100 may further comprise a heating element (not illustrated) for heating the hydride salt. For example, the heating element may be a heating plate located at the bottom of reservoir 20 beneath hydride salt powder 22.

[0035] In some embodiments, hydride salt powder 22 may further include a first catalyst configured to accelerate the hydrogen production from the hydride salt. Some nonlimiting examples for first catalysts may include, Ru, Co, Cu, Mg, Ni, and Fe, and their oxides, sulfides and nitrides. In some embodiments, hydride salt powder 22 may further include water absorption or materials for hydrogen absorption, for the slow release of water or hydrogen as needed.

[0036] In some embodiments, reservoir 20 is covered by a protective filter 25 configured to allow water molecules to reach the hydride salt and hydrogen molecules to escape towardsinner electrode 40 while maintaining the hydride salt inside reservoir 20. In some embodiments, protective filter 25 may be made from porous or perforated materials: e.g., polymer films, graphite, metals foils, ceramic materials and carbonized films, oxides, zeolites and the like.

[0037] In some embodiments, reservoir 20 may be a replaceable container, such as, a replaceable capsule or a replaceable bag that may be replaced upon the completion of the hydrogen production from all hydride salt powder 22, or when the production rate fell below a certain threshold value. In such an embodiment, container 10 may include an inlet comprising a connector for receiving replaceable reservoir 20, and reservoir 20 may include a corresponding connector to be connected to container 10. In some embodiments, replaceable reservoir 20 may be completely sealed in order to prohibit the entrance of humidity and the inlet connector in container 10 may be able to open / tear the seal and allow hydride salt powder 22 to enter container 10 and be exposed to humidity. In some embodiments, container 10 may be a breakable capsule.

[0038] In some embodiments, selective membrane 30 may cover container 10. In some embodiments, membrane 30 may be connected to container 10 using connectors 35. In the nonlimiting example, illustrated in Fig. 1 connectors 35 are made from silicone based polymer. As should be understood by the skill in the art, any type of connectors 35 that can connect membrane 30 to container 10 may be included in device 10.

[0039] Membrane 30 is designed to allow an entrance of water molecules into the container and blocks / restricts the exit of hydrogen molecules from escaping the container. Thus, humidity from the surrounding of device 100 may enter a container 10 reaching hydride salt powder 22 in reservoir 20 and producing hydrogen gas. Membrane 30 blocks / restricts the escape of the hydrogen into the surrounding, allowing the hydrogen to accumulate near inner electrode 40.

[0040] In some embodiments, membrane 30 may have a thickness of between 10 to 200 pm, and any value in between, for example, 20 pm, 40 pm, 50 pm, 80 pm, 100 pm, 120 pm, 150 pm and 175 pm. In some embodiments, membrane 30 may have an area of between 1 cm2to 400 cm2, or any value in between, for example, 5 cm2, 10 cm2, 20 cm2, 50 cm2, 100 cm2, 150 cm2, 200 cm2, 250 cm2, 300 cm2, and 400 cm2. In some embodiments, the pore size of membrane 30 may be between 2 to 6 nm and any value in between, for example, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, and 5.5 nm.

[0041] In some embodiments, selective membrane 30 is further configured to transfer either protons or hydroxide anions from inner electrode 40 to outer electrode 50. Membrane 30 may be any selective polymeric membrane either PEM membranes or AEM membranes.

[0042] In a nonlimiting example, for a PEM fuel cell membrane 30 may be made from sulfonated tetrafluoroethylene-based fhioropolymer-copolymer (Nation) with 1100 or 1000 EW, (Equivalent Weight), other perflourinated polymers, such as, polybenzimidazole PEM, and AEM containing quaternary ammonium or phosphonium, composite polymers (e.g., PBI+H3PO4) and other organic or inorganic cationic exchange polymeric membranes.

[0043] In some embodiments, inner electrode 40 is attached to the inner side of selective membrane 30 facing reservoir 20. In some embodiments, inner electrode 40 receives the hydrogen produced from the reaction of hydride salt powder with the humidity. In some embodiments, selective membrane 30 is PEM and inner electrode 40 is an anode comprising a second catalyst (e.g., Pt and Pd and their alloys) configured to convert hydrogen to protons. In some embodiments, inner electrode 40 may include in addition to the catalyst also ion conducting polymer matrix, a conducting filler (e.g., carbon particles) and the like. In some embodiments, gas diffusion layer (GDL) may be deposited on the free surface of inner electrode 40. In some embodiments, selective membrane 30 is AEM and inner electrode 40 is a cathode comprising a third catalyst (e.g., Ir, Ru, Pt and Pd and their alloys) configured to convert hydroxide anions and hydrogen to water and electrons.

[0044] In some embodiments, outer electrode 50 is attached to an outer side of selective membrane 30, opposite to inner electrode 40, and exposed to the oxygen in the air. In some embodiments, outer electrode 50 may include a catalyst, such as, (e.g., Pt and Pd and their alloys). In some embodiments, outer electrode 40 may include in addition to the catalyst also ion conducting polymer matrix, a conducting filler (e.g., carbon particles) and the like. In some embodiments, gas diffusion layer (GDL) may be deposited on the free surface of outer electrode 50. In PEM fuel cell, outer electrode 50 may produce water from protons, the oxygen in the air, electrons and protons. In AEM fuel cell, outer electrode 50 may produce hydroxide anions from water and oxygen in the air.

[0045] In some embodiments, water produced in the reaction may reenter container 10 and reservoir 20 and may further react with hydride salt powder 22. Therefore, even at relatively dry places with low amount of humidity in the air (e.g., below 20 vol.%) a sufficient amount of humidity will reach hydride salt powder 22, at least from the humidity produced by thefuel cell. In some embodiments, further humidity may be received from oxygen diffusion through membrane 30 and reaction of the oxygen with hydride powder 22 leading to water formation.

[0046] In some embodiments, container 10 may include a self-regulated component (such as, sponge or hydrogels soaked with water, covered by self-morphing material and the like- not illustrated) for slow release of water, to be used in dry environment as needed.

[0047] In some embodiments, device 100 may further include a cover unit 60, comprising a cover 62 covering at least a portion of the container and constraining the expansion of the container due to the production of hydrogen. Cover 62 may cover mainly selective membrane 30 in order to prevent water penetration when needed. Cover 62 may act as a selfregulation control mechanism that may stop the hydrogen production and apply it only on demand. For example, when container 10 is full and no electricity is consumed, it may be desired to stop the reaction and prevent container 10 from exploding. After consuming the hydrogen accumulated in container 10, cover 62 is detached (or partially removed) and the membrane is exposed to humidity again to produce more hydrogen. The ratio between the portion of membrane 30 covered by cover 62 to the portion exposed to the humidity in the air, may control the humidity provision rate, thus the hydrogen production rate.

[0048] Some nonlimiting examples for cover unit 60 may include nylon or foil (e.g. aluminum foil) that may prevent water from coming in. In some embodiments, cover unit 60 may include mesh / wires / frame 65 connecting the cover to container 10 and constraining the expansion of container 10 due to the production of hydrogen. As should be understood by the skill in the art any other motion blocking mechanism may be included in cover unit 60, for example, motion stopper, wires, cage etc. For example, in case of a rigid container 10 with a piston or folded structure, the stopper could be a simple knob.

[0049] Reference is now made to Figs. 2A and 2B which are images of portable electricity production devices connected to an electricity consumer with and without a cover, respectively, according to some embodiments of the invention. Devices 100 shown in Figs. 2A and 2B are similar to device 100 of Fig. 1. Devices 100 may provide electrical power to an electricity consumer 5, for example, the airborne platform illustrated, or a toy, a sensor, or a home appliance, or the like. Devices 100 may include substantially the same components of device 100 shown and discussed with respect to Fig. 1. Device 100 shown in Fig. 2A includes cover 62 and wires 65 while device 100 shown in Fig. 2B does not includethe cover at all. As shown in Fig. 2B, water molecules penetrate membrane 30 to meet the hydride salt powder 22 in container 10 and produce hydrogen which is provided to inner electrode 40 (located in the inner part of outer electrode 50) for producing electricity using the MEA (e.g., a fuel cell) assembled from inner electrode 40, membrane 30 and outer electrode 50 and the oxygen and optionally water molecules provided form the air to outer electrode 50.

[0050] Reference is now made to Fig. 3 which is an illustration of an airborne platform with a balloon according to some embodiments of the invention. An airborne platform 300 may include: a propulsion unit 306 powered by one or more electric motors 305 and one or more portable electricity production devices 301 providing electricity to one or more electric motors 305. Portable electricity production devices 301 may include a container 310 comprising a reservoir 320 comprising hydride salt powder 322, a selective membrane 330 covering the container, a first membrane exchange assembly (MEA) electrode (not shown) attached to an inner side of selective membrane 330 facing the reservoir 320 and a outer electrode 350 attached to an outer side of selective membrane 330, opposite to the inner electrode. In some embodiments, portable electricity production devices 310 may include substantially the same components as portable electricity production devices 100.

[0051] In some embodiments, container 310 is a balloon configured to expand due to hydrogen production, thus, since hydrogen is lighter than air, balloon-like container 310 may add to the lift forces of airborne platform 300. Balloon-like container 310 may be mounted on or to airborne platform 300. In some embodiments, airborne platform 300 may include more than one portable electricity production device 310 each being connected to and configured to power electric motors 305 of a corresponding propulsion unit 306. In some embodiments, airborne platform 300 may include a body, not illustrated.

[0052] Reference is now made to Fig. 4 which is an illustration of an airborne platform according to some embodiments of the invention. An airborne platform 400 may include: a propulsion unit 406 powered by one or more electric motors 405, for providing thrust to airborne platform 400, and one or more portable electricity production devices 401 providing electricity to one or more electric motors 405. Portable electricity production devices 401 may include substantially the same components as portable electricity production devices 100, for example, an inflatable container 410 and a selective membrane 430. In some embodiments, two inflatable containers 410 may each be included in each wing of body 402airborne platform 400. When inflated with hydrogen, inflatable containers 410 may add to the lift forces of airborne platform 400.

[0053] Reference is now made to Fig. 5 which is a flowchart of a method of producing electricity according to some embodiments of the invention. The method of Fig. 5 may be performed by a portable electricity production device, such as, portable electricity production devices 100, 301 and 401, discussed herein above.

[0054] In step 510, a portable electricity production device (e.g., device 100, 301 and 401) is exposed to humidity in the air. The natural humidity in the air may be diffuse via selective membrane 30, 330 or 430 toward reservoir 20 or 320 comprising hydride salt powder. The water molecules react with the hydride salt powder to produce hydrogen and solids, for example, salts and may be non-polluting.

[0055] In step 520, the hydrogen produced by a reaction between the humidity and the hydride salt powder may be collected inside containers 10, 310 or 410.

[0056] In step 530, the hydrogen may be provided to inner electrode, such as, inner electrode 40.

[0057] In step 540, outer electrode 50 or 350 may be exposed to the oxygen and optionally humidity in the air.

[0058] In step 550, electricity may be produced using a fuel cell formed by the inner electrode, the membrane and the outer electrode. For example, if membrane 30 or 330 is a PEM, the inner electrode may convert the hydrogen to protons and electrons and the outer electrode may produce water from the protons, the electrons and the oxygen in the air. Alternatively, if membrane 30 or 330 is an AEM, the outer electrode may produce hydroxide anions form oxygen, electrons and water molecules in the air and the inner electrode may produce water from electrons, the hydroxide anions and the hydrogen converted into protons.

[0059] In some embodiments, the method may further include providing the electricity to a consumer, such as, an airborne platform, a toy and the like.

[0060] Unless explicitly stated, the method embodiments described herein are not constrained to a particular order or sequence. Furthermore, all formulas described herein are intended as examples only and other or different formulas may be used. Additionally, some of the described method embodiments or elements thereof may occur or be performed at the same point in time.

[0061] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[0062] Various embodiments have been presented. Each of these embodiments may of course include features from other embodiments presented, and embodiments not specifically described may include various features described herein.

Claims

CLAIMS1. A portable electricity production device, comprising: a container comprising: a reservoir comprising hydride salt powder, a selective membrane covering the container and configured to allow an entrance of water molecules into the container and restricts the exit of hydrogen molecules from escaping the container, an inner electrode attached to an inner side of the selective membrane facing the reservoir, and an outer electrode attached to an outer side of the selective membrane, opposite to the inner electrode, and exposed to the oxygen in the air, wherein the selective membrane is also either a Proton Exchange Membrane (PEM), or an Anion Exchange Membrane (AEM).

2. The portable electricity production device of claim 1, wherein the selective membrane is an ion conductor.

3. The portable electricity production device according to claim 1 or claim 2, wherein the hydride salt is configured to react with water to evolve hydrogen gas exothermically.

4. The portable electricity production device of claim 3, wherein the hydride salt is selected from: LiH, LiAlH4, NaBH4, NaAlH4, NaH, LiBH4, MgH2, Mg(AlH4)2, Mg(BH4)2, Mg(AlH4)2and any combination thereof.

5. The portable electricity production device according to claim 1 or claim 2, wherein the hydride salt is configured to react with water to evolve hydrogen gas endothermically and wherein the device further comprises a heating element for heating the hydride salt.

6. The portable electricity production device according to any one of claims 1 to 5, wherein the reservoir further comprises a first catalyst configured to accelerate the hydrogen production from the hydride salt.

7. The portable electricity production device of claim 6, wherein the first catalysator is selected from: Ru, Co, Cu, Mg, Ni and Fe.

8. The portable electricity production device according to any one of claims 1 to 7, wherein the reservoir further comprises water absorbers.

9. The portable electricity production device according to any one of claims 1 to 8, wherein the reservoir is covered by a protective filter configured to allow water molecules to reach the hydride salt and hydrogen molecules to escape towards the inner electrode while maintaining the hydride salt inside the reservoir.

10. The portable electricity production device according to any one of claims 1 to 9, when the selective membrane is PEM and wherein the inner electrode is an anode comprising a second catalyst configured to convert hydrogen to protons.

11. The portable electricity production device according to any one of claims 1 to 10 when the selective membrane is AEM and wherein the inner electrode is a cathode comprising a third catalyst configured to convert hydroxide anions and hydrogen to water and electricity.

12. The portable electricity production device according to any one of claims 1 to 11 wherein the container comprises a flexible expendable material.

13. The portable electricity production device of claim 12, further comprising a cover, covering at least a portion of the container and constraining the expansion of the container due to the production of hydrogen.

14. The portable electricity production device according to any one of claims 1 to13, comprising 0.01-100 grams of hydride salt powder.

15. The portable electricity production device according to any one of claims 1 to14, wherein the reservoir containing the hydride salt powder is a replaceable capsule.

16. The portable electricity production device of claim 15, further comprising a piercing element configured to pierce the replaceable capsule prior to operating the device.

17. The portable electricity production device according to any one of claims 1 to 14, wherein the reservoir containing the hydride salt powder is further covered with a breakable cover configured to block the hydride salt powder from the moisture in the air when the device is not operative.

18. The portable electricity production device according to any one of claims 1 to 17, wherein an area of the selective membrane is between 1 cm2to 400 cm2.

19. An airborne vehicle comprising: a propulsion unit powered by one or more electric motors; and one or more portable electricity production devices according to any one of claims 1 to 18 providing electricity to the one or more electric motors.

20. The airborne vehicle of claim 19, wherein the container is a balloon configured to expand due to the hydrogen production.

21. A method of producing electricity, comprising: exposing a portable electricity production device to humidity in the air; wherein the device comprises: a container comprising: a reservoir comprising hydride salt powder; a selective membrane covering the container and configured to allow an entrance of water molecules into the container and restrict the exit of hydrogen molecules from escaping the container; an inner electrode attached to an inner side of the selective membrane facing the reservoir, and an outer electrode attached to an outer side of the selective membrane, opposite to the inner electrode, and exposed to the oxygen in the air, wherein the selective membrane is also either a Proton Exchange Membrane (PEM), or an Anion Exchange Membrane (AEM) ; collecting in the container hydrogen produced by a reaction between the humidity and the hydride salt powder; providing the hydrogen to the inner electrode; exposing the outer electrode to the oxygen in the air; producing electricity using a fuel cell formed by the inner electrode, the membrane and the outer electrode.

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