RU2165117C1 - Electrical energy generating unit - Google Patents

Abstract

FIELD: direct chemical-to- electrical energy conversion; chemical current supplies. SUBSTANCE: unit has electrode pairs each being, essentially, multilayer plate assembled of a solid and a gas-tight switch-over electrodes. Central part of plate is formed by solid electrode whose both sides are covered with semiconductor layer that functions as rectifying contact; gas-tight electrode is formed by semiconductor catalyst layer functioning as current-generating member and provided with current-carrying tracks. Conducting spacers inserted between plates complete series change-over circuit for solid and gas-tight electrodes of adjacent plates and set plates apart to provide clearance for gas mixture flow. There are through hollows in semiconductor layers and in gas-tight electrode to prevent shorting between spacer secured on one side of plates and solid electrode at points of electric contact with spacer. Plates may have through holes for passing some portion of working medium flow through plate-to-plate clearance; plates may be made of different geometry. EFFECT: enhanced power efficiency. 3 cl, 4 dwg

Description

 The invention relates to the field of direct conversion of chemical energy into electrical energy and can be used in current sources.

 A device for producing electric energy is known that contains an electrode pair consisting of a continuous and gas-permeable electrodes, equipped with commutation and separated from each other by a layer of semiconductor material with hole conductivity, having the properties of a catalyst for redox reactions in a gas working mixture of reactants and reaction products supplied to gas permeable electrode (Russian Patent N 2079934, H 01 M 8/10, 14/00, application. 16.03.94).

 The disadvantages of the known device are the difficulty in choosing the material of the semiconductor catalyst while ensuring optimal conditions for the formation of a double electric layer on its surface due to the adsorption of reagents and the effective course of the catalytic reaction. Since it is difficult to select such a material, the energy efficiency of the device and its efficiency are reduced.

 Closest to the claimed device by the number of matching essential features is a device for producing electrical energy containing an electrode pair consisting of commutated solid and gas-permeable electrodes separated from each other by a semiconductor catalyst of redox reactions in a gaseous medium of a reactant mixture and a rectifying contact, formed between the semiconductor catalyst and the solid electrode, wherein the thickness of the semiconductor layer layer the catalyst does not exceed the value of the diffusion length for minority charge carriers in a semiconductor material (Russian Patent N 2140122, H 01 M 8/10, 14/00, declared. 22.07.98).

 The disadvantages of the known device are as follows.

 Since the output voltage of a single electrode pair is limited to tenths of a volt, with a significant area of the working surface, the strength of the current flowing through the electrodes increases. This will cause ohmic loss of the output power and require an increase in the cross section of the electrodes, which, in turn, leads to a deterioration in the weight characteristics of the device. To increase the output voltage of the device, it is advisable to perform it in the form of an assembly of series-connected electrode pairs with direct electrical contact between the gas-permeable and solid electrodes of adjacent pairs. However, when using extended contacts of the surfaces of gas-permeable and solid electrodes with each other, their working surface decreases, the conditions for supplying a mixture of reagents and removal of reaction products to the surface of gas-permeable electrodes deteriorate, and the overall hydraulic resistance of such an assembly increases. As a result, the energy efficiency of the known device is reduced.

 The objective of the invention is to increase the energy efficiency of the device for generating electrical energy. The technical result that can be obtained using the proposed device is to increase the output voltage and output power.

 The problem is solved by the proposed device for producing electrical energy, containing at least one electrode pair, consisting of commutated solid and gas-permeable electrodes, separated from each other by a semiconductor catalyst of redox reactions in the gaseous medium of the reactant mixture and a rectifying contact formed between the semiconductor a catalyst and a continuous electrode, each electrode pair is made in the form of a multilayer plate, the central part which is formed by a solid electrode, the semiconductor catalyst and the gas-permeable electrode are located on both sides of the solid electrode, the portions of the gas-permeable electrode on the opposite sides of the plate are electrically connected to each other, the plates are arranged with a gap for the gas mixture to flow between them, and the electrodes are switched by means of conductive spacers located between the plates, while in the places of electrical contact of the spacers with continuous Through the electrode in the semiconductor layers and the gas-permeable electrode through holes are formed. In addition, through holes can be made in the plates, and the spacers can be fixed on one side of the plates. The implementation of the electrode pair in the form of a multilayer plate with a central layer as a continuous electrode surrounded by semiconductor layers with a rectifying contact and an external gas-permeable electrode allows us to produce such plates of various geometric shapes, using a solid electrode as a substrate for applying the corresponding coatings. The use of electrically conductive spacers allows you to dial a package of plates placed with the necessary gap, with a serial electrical switching of the electrodes to increase the output voltage. Moreover, the contact area of the remote controllers with the electrodes is a small fraction of the area of the plates and practically does not affect the value of the total working surface of the catalyst. As a result, the mixture is effectively accessible to both surfaces of the plates and optimal thermo-hydraulic parameters of the gas flow can be ensured for the catalytic reaction to proceed efficiently.

 The proposed device for generating electrical energy is shown in the following drawings. In FIG. 1 is a diagram of a device with a cut of one plate, in FIG. 2 - views B and C of FIG. 1, in FIG. 3 and 4 are enlarged breakouts of FIG. 1 and type B of FIG. 2.

 The device comprises a package consisting of multilayer plates arranged one after another, having the form of disks 1 with a central hole. The central part of the disk is a continuous electrode 2 and is surrounded by a layer of semiconductor catalyst 3. A rectifying contact is formed between this electrode and the catalyst, to create which an intermediate semiconductor layer 4 can be used. On the catalyst surface there are conductive paths of cellular geometry, of which gas permeable is formed on the entire surface of the disk electrode 5. On one side of the disk in the gas-permeable electrode and semiconductor layers there are three through circular recesses through Three cylindrical spacers — current outlets 6 soldered by one end face into a continuous electrode — are brought out with an annular gap relative to the catalyst layer and the gas-permeable electrode. The opposite ends of each spacer protrude above the surface of the given disk by the size of the gas gap 7 and are in contact with the conductive paths of the adjacent disk, ensuring the distance of the disks from each other and the series electrical connection of the electrodes. The conductive paths are expanded in places of their possible contact with the remote controllers to the size of the latter. The connection of the extreme disks of the package with an electric load 8 is provided using current-output terminals 9 and 10, the end surfaces of which are identical in shape to the corresponding surfaces of the disks. One or both terminals have central holes corresponding to similar holes in the disks. The package of disks can be placed in a common case (not shown in the drawings).

 The proposed device operates as follows.

 The gaseous mixture of fuel and oxidizer 11 through the central hole in terminal 9 enters the channel formed by the central holes in the disks, from which it flows into the slotted channels formed by the gaps between the disks. This ensures that the mixture flows around the entire surface of the disks, and the spent mixture exits from the device along their periphery. In this case, a catalytic oxidation reaction of fuel occurs on the surface of the semiconductor catalyst of each disk, accompanied by the processes of adsorption of reagents and desorption of gaseous reaction products, causing the generation of nonequilibrium electron-hole pairs in the semiconductor layer. As a result of the separation of electron-hole pairs by rectifying contacts, a potential difference arises between solid and gas-permeable electrodes. The electric current carried by minority carriers (electrons in a p-type semiconductor) is collected from the surface of the catalyst by the conductive paths of gas-permeable electrodes on both sides of the disks to the contact areas of these electrodes with spacers soldered into adjacent disks. Through remote controllers, current flows into solid electrodes and through rectifying contacts, which only minority carriers pass, into a semiconductor catalyst. Serial switching of each disk in an electric circuit formed by means of remote controllers and terminals leads to an increase in the output voltage at the load.

 Example.

The device contains a pack of disks with a diameter of 50 mm and a thickness of 0.5 mm, with a central hole of 12 mm in diameter, made of metal with a low electron work function (for example, titanium). On the surface of each disk, a catalytic coating up to 1 μm thick based on transition metal oxides (e.g. NiO) and metal conductive paths with high work function (stainless steel, Ni, etc.), forming a gas-permeable electrode with a cellular surface and with a characteristic mesh size of ≈2 mm. In this case, a rectifying contact (Schottky barrier) occurs between the disk material and the coating. The distance between the discs is not more than 0.5 mm is supported by three stainless steel spacers with a diameter of 2 mm, mounted on one side of the disc. At a working temperature of the disks of 320 ^o C and the use of a mixture of acetylene with an excess of air relative to stoichiometry, each disk generates a current of more than 0.8 A at a voltage of about 0.3 V. With the number of disks in the package equal to 40 pcs., Rated power the device is 10 W with an output voltage of 12 V and an energy conversion efficiency of up to 20%. Such a device can be used as an autonomous source of electrical and thermal (up to 40 W) energy, for example, for automatic alarm systems, control, communications, etc.

 Multilayer plates, representing electrode pairs, can be made with different geometric shapes, determined from the specific purpose of the device and the conditions of its operation.

Claims (3)

 1. Device for producing electrical energy, containing at least one electrode pair, consisting of commutated solid and gas-permeable electrodes, separated from each other by a semiconductor catalyst of redox reactions in a gaseous medium of a reactant mixture and a rectifying contact formed between the catalyst and the solid electrode, characterized in that each electrode pair is made in the form of a multilayer plate, the central part of which is formed by a continuous electrode ohm, the semiconductor catalyst and the gas permeable electrode are located on both sides of the solid electrode, and the portions of the gas permeable electrode located on opposite sides of the plate are electrically connected to each other, the plates are located with a gap for the gas mixture to flow between them, and the electrodes are switched by means of electrically conductive remote controllers, located between the plates, while in the places of electrical contact of the remote controllers with a solid electrode in the semiconductor layer x and a gas permeable electrode are formed through holes.  2. The device according to claim 1, characterized in that the through holes are made in the plates.  3. The device according to claim 1, characterized in that the spacers are mounted on one side of the plates.

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