WO1982000922A1 - Voltage generating device utilizing thermovoltaic cells and method of making - Google Patents

Abstract

A voltage generating device comprises a first (14) and a second (16) electrode having conductive surfaces of different materials, the first electrode (14) having a greater electron heat flux than that of the second electrode (16) and the heat flux is appreciably increased when the electrode is subjected to an additional thermal excitation and also has an increased positive potential compared to an electrolyte (12) in which these electrodes are kept in contact on the surface during this thermal excitation. Several cells (10) comprising this first and this second electrode and an electrolyte (12) are sandwiched and internally connected in series so that the voltage of the resulting device is multiplied by the number of cells (10) contained in the device sandwich. Electric current can be extracted from individual cells or from a sandwich assembly of a series of cells when an external load resistor (34) is connected to the terminals (36, 38) of the electrodes of the device. When placed in an initial enclosure (40) thermally separated from an associated enclosure, the thermovoltaic cell (10) can be used as an essential element of a heat pump to extract thermal energy in the form of heat from its environment in the enclosure (42) and to transfer this heat to the associated enclosure (44) using an electric current passing through a load resistor (34) connected to the cell, this resistor being physically and thermally separated from the initial enclosure and arranged in the associated enclosure.

Description

VOLTAGE GENERATING DEVICE UTILIZING THERMOVOLTAIC CELLS AND METHOD OF MAKING

BACKGROUND OF THE INVENTION

The present invention relates to voltage generating devices or cells and, more specifically to energy generating cells capable of producing an electrical voltage derived from the ion or charge carrier concentration of an electrolyte and the relatively different work functions of the associated electrodes of the device. The interaction between the positive electrode and the electrolyte is one of charge exchange or flow and does not necessarily involve any chemical reactions between the electrodes and the electrolyte.

The prior art which may appear initially to relate to the present invention has been characterized as ionic generating devices, thermal batteries, solid state thermally active batteries, sea water batteries and the like.

In the sea water batteries, the cells thereof convert chemical energy to electrical energy. Such a prior art device may be seen as described in U. S. Patent No. 3,907,596, to Albert E. Ketler, Jr., issued September 23, 1975; a solid state thermally activated battery may be seen as described in U. S. Patent No. 3,725,132, to J. R. Moser, et al, issued April 3, 1973; another type of thermal battery may be seen as described in U. S. Patent o. 3,899,353, to Masao Tomita, issued August 12, 1975; and a type of ionic detecting device may be seen as described in U. S. Patent No. 4,074,027, to Robert F. Akers, et al, issued February 14, 1978.

Thus, the prior art discloses a wide range of chemically activated cells and/or battery devices which represent a broad variety of capabilities for the possible detection and generation of electrical voltages or currents. In. general, the majority of these prior art devices rely primarily upon chemical reactions within the devices for their operation, that is, some type of galvanic corrosion of an electrode in the presence of an electrolyte.

The. prior art disclosure given in U. S. Patent No. 4,074,027, noted herein above, depends somewhat upon the ion concentration of an electrolyte for its operation. However, the most striking aspect of its novelty and operation is dependent upon the use of an electrode of copper in its preferred embodiment which has been irradiated with electromagnetic energy at a specified wavelength for excitation of the K-shell electrons of the copper atom. In this prior art device irridation of the electrode is critical and important to its successful operation.

From the foregoing discussion the closest prior art is exemplified by U. S. Patent No. 4,074,027, which consists of first and second electrodes made of dissimilar metals, one of said electrodes being irradiated with electromagnetic energy at a specific wavelength, for the purpose of exciting specific atoms of the molecular structure of the electrode. However, there is no specific disclosure, of what mechanism is utilized to effectuate the ion detection as a function of such irradiation and therefore, no thorough understanding of the precise process by which the irradiated electrode function is disclosed.

The present invention is uniquely different from the prior art device in that it is neither dependent upon the directed irradiation of either of the electrodes or chemical reaction between electrodes and the electrolyte for its operation and novelty.

SUMMARY OF THE INVENTION

In accordance with the present invention a voltage generating device utilizing thermovoltaic cells is disclosed wherein an electrolyte containing an equal concentration of plus and minus charge carriers is sandwiched between two dissimilar conductive elements which function as electrodes of the cells. More specifically, in a preferred embodiment of the present invention the electrolyte of the cells is a liquid aqueous salt solution, while the first electrode of the sandwich arrangement has a larger thermal flux of electrons than the second electrode and therefore, has a larger positive electrical potential with respect to the electrolyte, such that an open-circuit voltage is presnt, and as charge moves from the positive electrode to the negative electrode through an external load resistance, electrical energy is generated at the expense of an internal process involving thermal energy effects. Among the objects of the present invention is the provision of a voltaic cell which has means of continually and efficiently generating voltages between two electrodes without the presence of any chemical reaction between the electrolyte and electrodes.

A further object of the invention is the provision of a thermovoltaic device in which the electrolyte may be either a liquid, solid or gas containing equal concentrations of plus and minus charge carriers.

Another object of the invention is the provision of a device in which several thermovoltaic cells can be connected together in series internally such that the voltage thereof is a multiple of the number of cells in the device.

Still another object of the invention is the provision of a device which thermally cools itself as electrical power is dissipated in an external Joad resistance connected thereto.

Yet another object of the invention is the provision of a device in which there is an electric potential gradient induced adjacent to the surface of the positive electrode which attracts negative charges existing in the electrolyte towards the positive electrode and repells positive charges in the electrolyte away from the positive electrode.

Still a further object of the invention is the provision of a device that can convert the heat of its local environment directly into electricity without the use of moving parts.

Yet a further object of the invention is the provision of a heat-pump wherein all or part of the thermal energy in an initial environment is transformed or converted into electrical energy by means of a thermovoltaic device, then transmitted by electrical conductors to another environment at higher temperature and reconverted into heat by dissipation in an external load resistance.

Briefly, the above stated and other objects of the invention are achieved by the provision of a thermovoltaic generating device including an electrolyte sandwiched between two conductive electrodes, one of said electrodes having a larger thermal flux of electrons than the other electrode and a larger positive electrical potential with respect to the electrolyte than the other electrode. In operation, the individual cells of the device generate a voltage by some of the thermally excited electrons in the positive electrode emigrating therefrom out into the electrolyte which are replaced by electrical charges from the electrolyte as a result of an electric potential gradient which is induced near the surface of the electrolyte. The resulting exchange of charge carriers at the surface of the positive electrode adjacent the electrolyte accounts for the possible movement of electrical charge from the positive electrode to the negative electrode in an external circuit if they are connected to one another through an external electrical resistance load.

BRIEF DESCRIPTION OF THE DRAWINGS

The realization of the above features and advantages along with others of the present invention will be apparent from the following description and the accompanying drawings in which:

Figure 1 is a fragmentary cross-sectional view of a portion of a thermovoltaic cell illustrating the relative position of the elements of a cell embodying the present invention;

,

Figure 2 is a cross-section view of three thermovoltaic cells connected in series embodying the present invention;

Figure 3 illustrates an embodiment of the present invention wherein a thermovoltaic device is connected to a matching load resistance for transferring heat from one reservoir of a chamber containing one or more cells connected in series to a second reservoir of the chamber containing a matching load resistor;

Figure 4 illustrates another embodiment of the invention wherein a group of cavities are connected in a series and/or a Branching arrangement to be utilized advantageously to heat and/or cool the various enclosures;

Figure 5 is a plot of voltage versus temperature in degrees Rankine, (^OR) , which illustrates the operation of a thermovoltaic device in accordance with the present invention wherein the voltage output of the cell varies linearly with temperature;

Figure 6 is a plot of the voltage (V) versus the current (I) for a cell with stainless steel and aluminum foil for electrodes which illustrates the load line therefore as it compares with a theoretical load line shown in the plot;

Figure 7 is a plot of the natural logarithm of current density divided by temperature squared versus the reciprocal of temperature illustrating agreement with Dushman's equation; Figure 8 is a plot of voltage (V) versus current density (J) for three different cells where the positive electrodes are stainless steel, stainless steel plated with gold and stainless steel plated with rhodium illustrating the improvement in the perform

, ance of the thermovoltaic cell by utilizing materials for the positive electrode which provide a larger flux of the thermionic electrons;

Figure 9 is a chart which summarizes the predictable performance of a thermovoltaic cell at various temperatures illustrating the practical use of such cells in terms of power output;

Figure 10 is a diagramatic sketch of another embodiment of the present invention illustrating a fragmentary cross-sectional view of a thermovoltaic cell where a heated electrolyte flows through the cell;

Figure 11 is a cross-sectional view of a thermovoltaic device which is adapted to permit a heated liquid electrolyte to flow through the device in a manner as illustrated in Figure 10; and

Figure 12 is a cross-sectional veiw of the thermovoltaic device shown in Figure 11, taken along the line 12-12.

In accordance with the present invention a class of voltaic cells is disclosed which obey the first and second laws of thermodynamics. Gibbs and Helmholtz independently derived an expression for the open circuit voltage of an electro-chemical cell as follows :

which after integration, becomes:

(2)

In the above equation, ΔX is the change in chemical potential of a unit charge as it moves through different chemical species in the cell, β is the temperature coefficient and T is the temperature of the cell.

In accordance with the present invention it has been discovered that commercial electro-chemical cells are molecular ions in an electrolyte solution to transport charge from one electrode to another. During such process there usually is a different chemical reaction at each electrode and there is a net chemical change within the cell as charge is transferred. The second term on the right side of equations (1) and (2) is usually small compared to the first, and has generally been ignored in the prior art. In accordance with the present invention it has been recognized to correspond to the thermal energy in the cell that is converted directly into electrical energy independent of any chemical changes which may occur.

Thus based upon the thermodynamics of the situation alone, the present invention discloses a class of cells in which there are essentially no chemical changes during the generation of voltages. More specifically, cells of the present invention comprise an electrolyte, in the form of a liquid, solid or gas, sandwiched between two dissimilar conductive surfaces that are essentially chemically inert to the electrolyte. The thermal fluxes of posi tive and negative charges from the electrolyte to the electrodes are unequally influenced by the thermal flux of electrons from the dissimilar conductive surfaces causing charge separation and an induced electric field in thin boundary layers at each elec , trode. Since the thermal electron fluxes in the dissimilar conductive surfaces differ, the sheath or barrier potentials at each electrode differ, and there is a net open circuit voltage. Analysis in accordance with the present invention reveals that the open circuit voltage (V_OC) is proportional to temperature as required by the laws of thermodynamics and the Gibbs-Helmholtz relationship.

With reference to Figure 1, there is shown a cross-sectional view of a portion of a thermovoltaic cell 10 in accordance with the present invention comprising an eletrolyte 12, a first electrode 14, and a second electrode 16. There is shown adjacent electrode 14, a sheath potential (Φ₁) 18, and a sheath thickness (λ ₁) 20, and adjacent electrode 16 a second sheath potential ( Φ₂ ) 22, which is less than Φ and a second sheath thickness (λ ₂) which is equal to λ₁ . As shown, both of the sheath potentials Φ₁ and Φ₂ are positive due to the copious injection of electrons from the electrodes when thermionic emission occurs. As illustrated electrode 14 is a better emitter than electrode 16 such that a positive conduction current density J is illustrated as flowing from electrode 16 to electrode 14 and the resulting output voltage is the difference between the sheath potentials (Φ₁ ) and ( Φ₂) as expressed by the equation: (3)

where J is the conduction current density and б is the conductivity of the electrolyte. λ ₁ and λ ₂ are the respective sheath thickness of the electrodes 14 and 16, or the Debye length which is expressed by the equation:

(4)

where ∈_θ is the permittivity of free spece, and n is the concentration of plus and minus charges in the electrolyte. It has been observed that λ ₁ and λ ₂are much less than S, and that for S less than 10^-3m. the conductivity is so large in those electrolytes of interest that

(5)

and consequently equation (3) can be written: (6)

The relationship between the voltage (V) and the conduction current density (J) has been derived by writing the charge conservation equations at each interface of the electrodes. Thus, the conduction current density at electrode 14 is:

(7)

The foregoing equation is based upon the fact that the flux of negative and positive charges from the electrolyte to electrode 14 are

respectively,

where

(8)

and the thermionic flux of electrons from electrode 14 to the electrolyte is J₁ . In equation (8) Φ is the sheath potential of the electrode, B is the charge on an electron, k is Boltzmann's constant and T is the temperature.

A similar analysis for electrode 16 gives a second equation,

(9)

Equations (7) and (9) may be solved for Φ ₁ and Φ₂ respectively:

(10)

(11)

so that equation (6) may be used to express the voltage generated by a thermovoltaic cell:

(12)

which includes the previously stated assumption that S is much greater than λ ₁ and λ ₂; and further, it has been discovered in those cases of interest, the thermionic current densities far exceed the thermal current densities in the electrolyte, such that J₁ ² is greater than J² ₂ which is much greater than J- J₊

Using equation (12) the open-circuit voltage of (V_oc) a thermovoltaic device is found by setting J=0 to be:

The short-circuit current (J_sc) is found by setting V=0 in equation (12)

(14)

and since it has been observed that J₁ i0 much larger that J₂

- ⁽¹⁵⁾

An expression for the maximum predictable power density (W) which can be generated by a thermovoltaic device is. found using equation (12) since it has been observed that J₁/J₂ can be as large as 10⁶ or greater. If J₁/J₂ is equal to 10⁶, then the maximum power density is:

^, (16)

where P is the power generated, A is the area of the cell and S is the thickness of the electrolyte.

It has been found that a liquid such as common water can provide a power density at room temperature of 100 watts/m³ and greater when the thickness of the electrolyte is less than .007 inch.

Further analysis and experiments relating to equation (16) indicate that the first electrode 14 should have a high thermionic flux of electrons, that is, J₁ should be very much larger than J₂; that operation at higher temperatures gives higher power; and that the electrolyte thickness should be as small as possible.

Using Dushman's equation for thermonic emission:

(17)

it is possible to express the voltage generated by a thermovoltaic cell in terms of Richardson's constant (A) and the work function (w) of the electrode. That is: (18)

(19)

By using equation (19) with equation (13) we derive the following equation for V_oc (20)

In this form equation (20) satisfies the Gibbs-Helmholtz relationship, and hence it satisfies the first and second laws of thermodynamics.

Referring now to Figure 2 there is shown a cross-sectional view of three thermovoltaic cells 10 which are connected in series. As shown electrodes 16 and 14 of alternate cells are connected to one another to complete the series connections. A dielectric gasket 26 at each end of the spece between electrodes 14 and 16 is utilized to retain the electrolyte between electrodes 14 and I6 of each cell 10. A second dielectric material 28 is employed along gaskets 26 to retain the entire configuration in place as a series of connected cells. As shown in Figure 2 a portion of electrode 14 designated 30 at each end thereof end and a portion of electrode 16 designated 32 at each end thereof, respectively constitute fins or exposed ends. The extending and exposed fin sections of each cell or a

, series of cells, in accordance with the present invention, may be utilized as means for absorbing thermal energy from the environment in which the cells may be located.

Figure 3, illustrates an embodiment of the invention,wherein a thermovoltaic device 10 is connected to a matching load resistance 34 through external leads 36 and 38 which are respectively connected to electrodes 14 and 16. As shown in the drawing the thermovoltaic device 10 and matching load resistor 34 are enclosed in a chamber 40, having two cavities 42 and 44 within said chamber. An internal member designated 46 divides the chamber 40 into the cavities 42 and 44. Electrical leads 36 and 38 pass through apertures in chamber section 46 and are electrically insulated therefrom. The cabities are hermetically sealed at opposite ends of the apertures 48 and 50 with a suitable sealing material.

Also shown in the drawing are two temperatures of the respective cavities 42 and 44. Prior to closing a switch 56, the two chambers 42 and 44 are substantially at the same temperature. Operation of the arrangement shown in Figure 3 is commenced by closing switch 56. After switch 56 is closed current flows from the device 10 and the temperature of cavity 42 commences to cool down, while the temperature of cavity 44 is raised. The maximum induced temperature difference between the two enclosures depends upon the power output of the cell device 10 and the heat conductance between the two thermal enclosures 42 and 44.

In the arrangement shown in Figure 3, there are at least two externally important applications and uses of the thermovoltaic device according to the present invention illustrated. First, it can be appreciated that the device 10 is useful as a means of generating electrical power and thus acting as a cooling device or a heat-pump. A further useful function of the thermovoltaic device illustrated by Figure 3 is that heat may be introduced into enclosure 42 by appropriate means to enable it to continue its current generating capabilities. More specifically and importantly, the thermovoltaic device is capable of absorbing heat from its surrounding environment and converting the same to electrical energy.

This feature of the thermovoltaic device makes it uniquely adaptable for receiving and capturing thermal energy from its environment, such as thermal energy from the sun or thermal heat (energy) from fossil or nuclear fuel or from the smoke and heat exhaust from the stack of a oil, gas, or coal fired power station. These hot exhaust gases are traditionally vented to the open atmosphere of the stack's envrionment and are lost. The present invention enables such traditionally wasted heated gases to be readily used for a wide range of practical purposes and uses.

A further useful application of the present invention is shown in Figure 4, wherein a chamber 58 and a series of enclosures or cavities 60 through 70 are shown within the chamber. Enclosure 60 has an initial thermovoltaic device 10 feeding cavity 62 which utilizes the thermal energy generated by the resistor 34 to generate heat for the next series connected cavity 64. This process is repeated for as many cycles as may be desired. Con

, tinuing with the description of Figure 4, there is shown a second thermovoltaic device 10 in cavity 68 which is coupled to branching cavity 72.

Thus, Figure 4 illustrates the use of the thermovoltaic device 10 and cavity arrangement wherein such cavities may be used in series or with branching circuit cavities. This flexibility provides broad utility of device 10 for many applications to thereby enhance the novelty of the device.

Another modification to the application of thermal energy to a cavity is shown in cavity 64 where a second resistor 34 is fed By a branching cavity 74.

It will be readily recognized that the various cavities may be thermally heated by sources other than by the resistors 34 to provide broad use and versatility to the use of the thermovoltaic device.

Continuing with the description of the figures, Figure 5 is a plot of actual data points for voltage (V_oc) versus temperatures (^oR). The plot of data is typical data derived from many cells which have been evaluated. The data demonstrates that the thermovoltaic cell voltage is linear in relation to temperature.

Figure 6 is a plot of voltage (V) versus current (I) for a typical thermovoltaic cell in accordance with the present invention. Shown is a plot of the voltage versus current for a theoretical curve 78 utilizing the equations disclosed (equations 12, 13, and 15). An actual curve is designated 80 and the points which determine the shape of this curve were derived by using resistances of 500 ohms, 50.4 ohms, and 5.04 ohms. As can

, be seen, the actual curve is similar in shape to the theoretical curve. The similarity in the form of the curves illustrates agreement between actual discovery and measurement with the theory developed herein.

Figure 7 is a plot of the versus reciprocal of tem

perature ) at various temperatures. The curve, a straight

line fitted to the data points, confirms the fact the thermovoltaic cell of the present invention follows Dushman's equation (17).

Figure 8 is a plot of three different curves for voltage versus current for three different cells where the positive electrodes 14 were respectively, stainless-steel (SS); stainless-steel plated with gold (G); and stainless-steel plated with rhodium (R); and the negative electrode 16 was aluminum foil having a thin oxide coating adjacent the electrolyte. Each of the cells were tested with resistor loads of 5.04 ohms, 50.4 ohms, and 500 ohms, to derive the points for fitting the respective curves.

Figure 8 illustrates that the current generating capacity of thermovoltaic cells may be enhanced by use of materials which emit higher thermionic fluxes of electrons and do not oxidize readily.

While Figure 8 has been discussed with reference to stain less-steel, stainless-steel plated with gold, and stainless- steel plated with rhodium, it should be noted that such material as copper, silver, platinum, palladium, alloys of the foregoing or other metals or ceramics treated to have electrical conductive properties may be utilized as envisioned by the invention.

Referring to Figure 9, there is shown a chart which illustrates the performance capabilities of thermovoltaic cells in accordance with the present invention. The chart lists four parameters associated with the cells and illustrates the unique capabilities of the present invention over prior art devices. As shown in the chart, as the temperature (T) of the environment and thus as the temperature of the cell increases, the current (J), voltage (V) and the power density (W) increases, as would be expected utilizing the theory and equations 12, 16, and 17 derived and set forth herein.

Referring to Figure 10, there is shown a diagramatic sketch of a segment of a thermovoltaic cell 10' having a positive electrode 14', a negative electrode 16' and an electrolyte 12' which flows Between the two electrodes. Connected between the electrodes 14' and 16' is a load resistor 34 through which current flows when switch 56 is closed.

As shown in Figure 10, electrolyte 12' passes through the cell 10' to an outlet line 80 and thence to an external heat source 78 which functions to heat the electrolyte 12' as it passes along the flow-path of the electrolyte. The heated electrolyte 12' flows out of the heat source along a path 82 to a liquid pump 76 which functions to maintain the flow of liquid into cell 10' along an inlet path 88. As can be seen from Figure 10, the mode of operation of the thermovoltaic device is different than that discussed where the electrolyte was a static liquid sandwiched between the electrodes.

The discussions hereinabove were directed toward heat being delivered to the device by conduction or radiation from an external source. In constrast, this embodiment illustrates the heat is being conveyed by the liquid electrolyte directly as heat is removed from the circulating electrolyte.. It should be noted that the rate of flow of the liquid electrolyte may be controlled so that the maxiτmιm thermal energy is extracted therefrom. The rate of flow may depend upon the temperature of the circulating liquid electrolyte 12', the rate of thermovoltaic heat-to-electrical current conversion, the resistance of the load resistance and other factors.

Shown in Figure 11 is a thermovoltaic device having an internal configuration adapted to permit the flow of electrolyte 12' therethrough when utilized in an embodiment as illustrated in Figure 10. In Figure 11 the device has a positive electrode 14' having a plurality of inward extending elements 84 and a negative electrode 16' having inward extending elements 86. Also shown are two T-shaped elements 92, and two end U-shaped elements 90. The elements 90 and 92 hold the positive and negative electrodes electrically separated while preventing any leakage of the electrolyte as it flows and circulates through the main body of the device. Figure 12 is a view of the device shown in Figure 11, illustrating the flow of the electrolyte 12' through device 10' between the extensions 86 of negative electrode 16'.

The mode of operation for the device with respect to the thermo-electric conversion between the electrolyte 12' and the electrodes 14' and 16' is identical to that discussed hereinabove. The embodiment illustrates another way in which a larger and high capacity device can be constructed, while utilizing the benefit of a heated circulating electrolyte.

Yet another embodiment within the scope of the present invention is where the thermovoltaic cell contains a radio active isotope, such as plutonium, radium or tritium and the like. The isotope material may be disposed internally such that it generates heat within the cell derived from the radio active particles as the isotope decays during its half-life. The specific location of the isotopes within the cell is not critical and may be disposed, for example, as shown in Figure 11 at location cavaties 94 and 96. A single location may be utilized or it may be desirable to utilize multiple placements of the isotopes within the cell.

Various advantages may be derived by the use of these radio active isotopes in cells of the present invention. For example, it may be desirable to maintain the voltage generating capabilities of a cell at some minimum level when the external thermal energy of the environment in which the cell is disposed fluctuates or it may be desirable to utilize a cell containing an isotope to function as a long-life signal source or generator device in applications where the cell is disposed in some remote location not readily accessible for replacement. Numerous other applications and uses of this embodiment will be discovered by others as they become more familiar with the utility of the cells containing an isotope material.

While the thermovoltaic cells or devices of the present invention have been described with reference to only several particular embodiments, it will be understood that various different modifications or changes could be made in the construction, application, use of material, electrolytes, etc. thereof without departing from the spirit and scope of the invention. For example, the present invention encompasses the use of solid electrolyte materials such, as semiconductive material of the class including germanium, silicon and gallium arsenide or solid electrolyte material consisting of fibrous material such as paper, cloth or synthetic substances in which liquid electrolyte is suspended.

In another embodiment of the present invention, it has been found that either the positive or negative electrodes may be coated with conductive coating materials on their surfaces adjacent the electrolyte to form respectively, high or low, electron thermionic emitters, in lieu of the metallic electrodes disclosed and taught hereinabove. One of the primary advantages of utilizing such coatings appears to be economic or cost benefits to be derived in mass productions of certain types of thermovoltaic cells or devices. Such coatings are readily adaptable and com patable with modern manufacturing techniques and therefore offer additional benefits. Various types of coating materials may be employed such as inks containing electrical conductive materials such conductive particles and the like.

The invention also encompases the use of gas media for the electrolyte. However, it is readily recognized that the use of gas or gaseous plasma will require very high temperature operation and therefore may have certain limitations in view of current technology.

Accordingly, it is to be expressly understood that the foregoing description and disclosure shall be interpreted only as illustrative of the inventive concepts and the invention, and that the appended claims be accorded as broad an interpretation as is consistent with the basic concepts herein taught.

Claims

What is claimed as new is:

1. A voltage generating device comprising a sandwich arrangement of:

(a) a first electrode having a first predetermined surface area;

(b) a second electrode having a second predetermined mined surface area;

(c) an electrolyte sandwiched between said first and second electrodes containing an equal concentration of plus and minus charge carriers said first and second electrodes having dissimilar conductive surfaces, and said first electrode having a larger thermal flux of electrons than said second electrode as the conductive surfaces are maintained in surface contact with said electrolyte; and

(d) output means connected between said first and second electrodes for providing an electrical output to the outside environment of said output means.

2. The voltage generating device of Claim 1, wherein said first electrode is further defined as a positive electrode and said second electrode is further defined as a negative electrode.

3. The voltage generating device of Claim 1, wherein said first electrode is further defined as metal and being selected from the metallic group essentially consisting of stainless-steel, copper, gold, rhodium, silver, platinum and palladium and alloys of these or other metals and ceramics.

4. The voltage generating device of Claim 1, wherein said electrolyte is further defined as a liquid.

5. The voltage generating device of Claim 4, wherein said electrolyte is further defined as an aqueous liquid.

6. The voltage generating device of Claim 5, wherein said electrolyte is further defined as a non-aqueous liquid.

7. The voltage generating device of Claim 5, wherein said electrolyte is further defined as a salt, acid or base in a liquid mixture.

8. The voltage generating device of Claim 6, wherein said electrolyte is further defined as a hydrocarbon in liquid form.

9. The voltage generating device of Claim 7, wherein said electrolyte is further defined as common salt water.

10. The generating device of Claim 1, wherein said electrolyte is further defined as a solid material.

11. The generating device of Claim 10, wherein solid electrolyte is further defined as a semiconductor, and being selected from the semiconductor group essentially consisting of germanium, silicon and gallium arsenide.

12. The generating device of Claim 1, wherein said voltage output varies substantially linerally with the temperature of the surrounding environment.

13. The generating device of Claim 1, wherein said surface contact between said electrolyte and said first electrode is further defined as having thermally excited electrons migrating from said first electrode into said electrolyte which are replaced by negative charges from said electrolyte in the presence of an electric potential gradient induced near the surface of said first electrode adjacent said electrolyte. ,

14. The generating device of Claim 13, where said migrating exchange of charge carriers at the surface of said first electrode adjacent to the electrolyte causes charge from said first electrode to flow through a circuit external to the device to said second electrode when said first and second electrodes are connected to one another by means of an external load resistance.

15. The voltage generating device of Claim 1, wherein said first and second electrodes are further defined as each having at least one end thereof which extends beyond said surface contact with said electrolyte to thereby form fins for absorbing thermal energy.

16. The voltage generating device of Claim 15, wherein said output means is further defined as allowing current to flow through an external load resistance whereby said device cools itself if thermally insulated from said external load resistance.

17. The voltage generating device of Claim 1, wherein said second electrode is further defined as aluminum foil having a thin oxide film on its surface in contact with said electrolyte.

18. A device adapted to produce a thermal output when confined within an enclosure, comprising:

(a) a chamber having at least a first and second enclosure, thermally separated from one another; (b) a thermovoltaic device disposed in said first enclosure for generating an output voltage responsive to an existing ambient temperature inside said first enclosure; and

(c) an output load resistor connected to said thermovoltaic device through electrical conductive leads extending into said first enclosure from said second enclosure to provide means for said thermovoltaic device to transfer heat by means of an electrical current from said first enclosure into said second enclosure.

19. The device described in Claim 18, wherein said thermovoltaic device is further defined as a voltage generating device as described in Claim 1.

20. A voltage generating device comprising:

(a) a first electrode having at least one predetermined contact surface area;

(b) a second electrode having at least one predetermined contact surface area, said first and second electrodes, being disposed in fixed space relationship to one another with their contact surface areas opposite each other defining input and output ends and a separation therebetween;

(c) an electrolyte which flows between said fixedly disposed electrodes making continuous contact with said opposing surfaces along a flow path into said input and out of said output end containing an equal concentration of plus and minus charge carriers;

(d) means along said flow path of said electrolyte for , supporting the flow of said electrolyte into and out of said separation between said electrodes including a heating source, a liquid pumping means and liquid piping means; said first and second electrodes having conductive surfaces, and said first electrode having a larger thermal flux of electrons than said second electrode; and

(e) output means connected between said first and second electrodes for providing an electrical output from said device.

21. The voltage generating device of Claim 20, wherein said electrodes are further defined as having multi-contact surface areas in contact with said electrolyte.

22. A voltage generating device comprising:

(a) first and second U-shaped electrode enclosure members having a base and parallel legs extending from said Base, said members being held in fixed spaced relationship at the ends of their respective legs by electrical insulating means to form an enclosure region therebetween, each of said electrodes having a plurality of elements extending from each of said base legs of said electrodes toward each other within said enclosed region to thereby define multiple contact surfaces;

(b) an electrolyte which flows between said electrodes making continuous contact with said electrode con , tact surfaces within said enclosed region along a flow path into an input region formed by said electrodes and out of an output end of said region, said electrolyte containing an equal concentration of plus and minus charge carriers;

(c) means along said flow path of said electrolyte into and out of said enclosure region between said electrodes, including a heating source, a liquid pumping means, and piping means; said first and second electrodes being of dissimilar conductive surfaces, and said first electrodes having a larger thermal flux of electrons than said second electrode; and

(d) output means connected between said first and second electrodes for providing an electrical output from said device.

23. The device described in Claim 20, wherein said thermovoltaic device is further defined as having means for retaining a radio active isotope within said device.

24. The device described in Claim 20, wherein said thermovoltaic device is further defined as including a radio active isotope material within said device.

25. The device described in Claim 24, wherein said thermovoltaic device is further defined as having a radio active isotope material within said device from the group including plutonium, radium and tritium.

26. The voltage generating device of Claim 1, wherein said first electrode is further defined as having an electrically conductive coating material deposited thereon forming a surface coating of relatively high thermionic emission of electrons, said surface coating being in contact with said electrolyte.

27. The voltage generating device of Claim 1, wherein said second electrode is further defined as having a second electrically conductive coating material deposited thereon forming a surface coating of relatively low thermionic emission of electrons, said surface coating being in contact with said electrolyte.

28. The voltage generating device of Claim 1, wherein said second electrode is further defined as a metal or alloy of metals or ceramics having a relatively low thermionic emission of electrons.

29. The voltage generating device of Claim 1, wherein said electrolyte is further defined as a solid material in which a liquid electrolyte substance is suspended.

30. The voltage generating device of Claim 7, wherein said electrolyte is further defined as a solid material in which said liquid mixture is suspended.