CN1076809A

CN1076809A - Capacitive thermoelectric device

Info

Publication number: CN1076809A
Application number: CN 92113668
Authority: CN
Inventors: 伊万·I·格里戈特切克; 伊万·D·科茨米克; 维克托·V·内蒂亚加; 博丹·P·巴马蒂尤克
Original assignee: Zaha D, Walid uicker
Current assignee: Zaha D, Walid uicker
Priority date: 1992-10-29
Filing date: 1992-10-29
Publication date: 1993-09-29

Abstract

A kind of thermoelectric device that is used for cooling object includes the capacitor of two electrodes, and with object thermo-contact to be cooled.When capacitor repeated to do isothermal charging and adiabatic discharge, capacitor produced cooling effect.

Description

Capacitive thermoelectric device

The application is the part continuation application of No. 07/784544, the U. S. application submitted on October 29th, 1991.

The present invention relates to solid state thermoelectric device, more specifically say, relate to the thermoelectric device material.

The peltier effect that the work of general solid state thermoelectric device is based on, this effect are to occur by the flow through joint of different metal of electric current.Such device is made of two semiconductor pieces usually, one of them highly doped n section bar material, another low-doped P-type material.Partly be that conductor block is connected in parallel with heat by the electricity series connection.In this device, heat is absorbed at the cold junction place of so-called semiconductor piece, and to be proportional to by the semiconductor piece electric current, is delivered to so-called hot junction place.When electric current was added on the n type of series connection and the p N-type semiconductor N piece, electronics transitted to the higher energy level of n section bar material from the low-lying level of p section bar material.This similar diode operation produces heat, and is hot then transferred by two cold junction, and is pumped into the hot junction place through these pieces (parallel connection).

At present, bismuth telluride be modal be used for the peltier effect thermoelectric device partly lead material, this material demonstrates three required specific characters of thermoelectric device, i.e. high mechanical properties, high conductivity and low heat conductivity energy.The bismuth telluride Po Er of commercial manufacturing pastes device can reach about 65 ℃ temperature difference, the heat that the energy pumping is tens of watts.

Just generally speaking, in one case, the present invention is characterised in that thermoelectric device comprises two electrodes of being isolated by electrolyte.Each electrode all contains crystalline material, and crystalline material has Fan Dewaer stone road.The Fan Dewaer stone can hold electrolyte in the road, when applying voltage between two electrodes, forms two charge layers at the interface of Fan Dewaer stone road and electrolyte.The temperature that thermoelectric device demonstrates two cooling procedure stages descends, and comprises making alive between the electrode, forms bilayer with this, and makes double-deck discharge come alternate voltages by load.Utilize the material of selecting, thermoelectric device of the present invention shows, and two stage cooling procedures of every repetition reduce by 0.5 ℃ with regard to temperature, and a kind of important thermoelectric effect so just is provided.Have the compound in Fan Dewaer stone road and being described in further detail of the device that utilizes these compounds, to in following application documents, provide, the application of all propositions on the same day as " electrolytic double-layer capacitor ", also comprises thus with reference to " capacitive thermoelectric device " and " energy storage device ".

In most preferred embodiment, control added voltage, make said bilayer do the isothermal charging, and make double-deck adiabatic discharge.Be preferably, crystalline material is the chalcogenide of bismuth, and best two electrodes all comprise a kind of chalcogenide of bismuth of monocrystalline.In another most preferred embodiment, two electrodes all comprise the monocrystal particulate of crystalline material.By comprising the water conservancy diversion process that electrolyte is inserted into passage, make the Fan Dewaer stone road of crystalline material be suitable for holding electrolyte.Be preferably,, make electrolyte infiltrate Fan Dewaer stone road, reach insertion by means of sufficiently high water conservancy diversion voltage.Interelectrode polarity is preferably made periodically anti-phase change water conservancy diversion voltage.

In another case, the invention provides a kind of thermoelectric device usually with cooling material.Device contains capacitor, and capacitor have two electrodes and with this material thermal coupling.When capacitor is done isothermal charging and adiabatic discharge repeatedly, just provide cooling effect.Be preferably, capacitor is a double layer capacitor, is more preferably electrolytic capacitor.

Under the another kind of situation, generally speaking, the invention provides a kind of thermoelectric device that comprises two electrodes that separate by electrolyte.Each electrode all comprises porous material, and when voltage was applied between two electrodes, above-mentioned material can form electric double layer at the interface of itself and electrolyte.This device all demonstrates decrease of temperature in two cooling stages.Cooling comprises that making alive forms bilayer between the electrode, and by load the alternating voltage of double-deck discharge is changed.

In most preferred embodiment, porous material comprises a kind of compound, activated carbon and heat treated graphite of chalkogenide of bismuth, and preferably electrolyte contains sulfuric acid.Preferably to control the voltage that applies, make described bilayer do isothermal charging and adiabatic discharge.

Thermoelectric device of the present invention is by the circulation repeatedly of two stage cooling procedures, and the temperature that forms accumulation reduces, and so-called two stages are charge and discharge.Component compact, control is exquisite simple and easy, obviously is better than existing thermoelectric device.By following description and claim, other performance of the present invention and advantage will be more obvious.

Fig. 1 is the schematic diagram of an embodiment of thermoelectric device of the present invention;

Fig. 2 A is the schematic diagram at first water conservancy diversion device of accompanying drawing 1 in the stage;

Fig. 2 B is the schematic diagram at back water conservancy diversion device of Fig. 2 A in the stage;

Fig. 2 C is the schematic diagram of water conservancy diversion Fig. 2 A device in the stage in the end;

Fig. 2 D is the schematic diagram that comprises Fig. 2 A device that forms the electric charge bilayer; And

Fig. 3 is the sketch of the electric current of control thermoelectric device of the present invention.

At first, we describe the operation principle of thermoelectric device of the present invention in detail.Thermoelectric device of the present invention is a capacitive device, it is characterized in that, can hold very high charge density, quite high energy storage and very low internal resistance.Therefore, capacitor can reach very high discharge capability.In fact, the velocity of discharge can reach abundant thermal insulation soon.In addition, in the discharge process very abortion give birth to resistance heat or Joule heat.It is such that the back also will illustrate, these features of discharge process are so outstanding, so that can provide cooling effect by the work of following device.At first the capacitor element isothermal is charged to very high charge density, Here it is reduces device with the isothermal form

The adiabatic discharge of capacitor element then, thereby the raising device

, the result must make device cooling or cooling.Can understand charge and discharge cycles like this, regard it as classical Carnot cycle, circulating temperature wherein be directly connected to circulation dynamics with Change.

At this, the inventor recognizes, though any in theory capacitance structure all can be made thermoelectric (al) cooler, specific capacitor system and special device material are suitable for realizing thermoelectric-cooled most.Based on above-mentioned operation principle, desirable electric capacity cooling device comprises a kind of capacitance structure that can gather very high charge density and very low internal resistance; Particularly, the electrode internal resistance of ideal capacitance will keep lower.Provide these criterions, have been found that electrolytic double-layer capacitor will have very high electric charge to gather ability, just can be cooling device good capacitance structure is provided.Therefore, cooling device of the present invention is just based on the double layer capacity structure.

As an example of condenser charge density accumulation limit, the capacity of parallel plate capacitor amount provides by following formula usually, by analyzing the work electrical characteristics of this structure, at first considers

C＝ε ₀εS/d

ε wherein ₀Be constant; ε is the dielectric constant of capacitor electrode interpolar medium, and S is the electrode surface area of capacitor, and d then is the medium width of spaced-apart electrodes.The charge density of the capacitor of being given is admitted ability, and just, capacitance is limited by geometry, and promptly the medium by surface area, electrode spacing, electrode material character and spaced-apart electrodes limits.

The definition of the capacitance of double layer capacitor further will be determined by the double-decker and the geometry thereof of charging.This bilayer comprises the accumulation of the ion of the electric charge accumulation of electrode surface and electrode surface and electrolyte interface.Like this, for double-layer electrolytic capacitor, the width d in the capacitance equation is just provided by the distance between the center that constitutes two double-deck zones.This distance is several dusts, and therefore, given capacitor surface amasss and has very big capacitance.

Increase the surface area of electrode for capacitors, make it to surpass existing two-layer electrode, and through suitably selecting electrode material and electrolyte for use, the capacitance of electric capacity cooling device of the present invention just has a continuous bigger increase (admitting ability with charge density).In addition, as hereinafter describing in detail, electrode material that this is selected for use and electrolyte have very low internal resistance, and this work to cooling device is the parameter of a key.

Electric capacity cooling device of the present invention is using the material of Special Category, promptly is the compound that is mingled with of characteristics with the stratification structure, so, realized the increase of electrode surface area.The crystal layer that is mingled with compound comprises that these molecules or atomic plane also separate each other by Fan Dewaer stone road with low binding molecule or atomic plane together.In the lattice between molecule or atomic plane, these Fan Dewaersi zones have formed anisotropic passage, and the result is actually " two dimension " crystal structure.Inclusion material, common every millimeter material thickness has 10 ⁶～10 ⁷Layer.Because the van der waals force between crystal layer is faint, so the physics of the external alloy of lattice passage receivability is introduced or what is called is mingled with.

The inventor recognizes, particular type be mingled with compound, promptly the chalkogenide of bismuth especially comprises Bi ₂Te ₃And Bi ₂Se ₃Be suitable for being used to provide very much Fan Dewaer stone road, with the expansion electrode surface area.When lumping together when using with suitable electrolyte, by the electrode that these materials are formed, the height that just forms desired structure is bilayer uniformly.Those skilled in the art knows that the chalkogenide of bismuth presents the layer winding of molecular level stratification, and every layer is 3～4 by width

Fan Dewaer stone road separate.And the performance of the chalcogenide material of bismuth provides hereinafter, can referring to the pending application of submitting to same period of the present invention that is entitled as " Layered Crystalline Material Capable of High Guest Loading ".To the mensuration of material, the inventor has been found that the chalkogenide of bismuth, Bi ₂Te ₃Demonstrate best conductance, corresponding internal resistance is also minimum, therefore, is suitable for doing electrode material most; Yet Bi ₂Se ₃It is lower to demonstrate conductance, then is not best as electrode material therefore.

Must emphasize, when the chalkogenide of believing bismuth has good electrical properties, other inclusion material also can be used for electric capacity cooling device of the present invention, and the material that it is characterized by other crystalline texture that high charge density can be provided also can be used as electrode material, such as, activated carbon, porous material also can be used as electrode material.Porous activated carbon has increased the effective surface area of material.

In an embodiment of electric capacity cooling device of the present invention; Used and be mingled with electrode material.Be the Fan Dewaersi zone of using electrode material like this, make the surface of lattice passage,, thus, increase the surface area of the active electrode that surpasses macro surface significantly though, total electrode surface area is also made contributions in electrode interior.Following further describing forms double-deck equally with the electric capacity macro surface, and the surface in the Fan Dewaer stone road of electrode material also can form the bilayer with electrolyte.The discovery of this physical process and exploitation can make cooling device of the present invention, owing to increase result to the admittance ability of electric density, and realize the significantly effect of cooling.

Depend on cooling device selected be mingled with electrode material and electrolyte, be handled or " water conservancy diversion " the Fan Dewaer stone road of electrode, make it can admit electrolyte effectively.The situation of this requirement is to propose according to the compound radius of the size in Fan Dewaer stone road and electrolyte solvent thing ion.If the compound radius of solvate ion is greater than the Fan Dewaersi width of channel, electrolyte can not penetrate passage so, also just can not form double-deck in passage.Therefore, the material that has less than the Fan Dewaer stone road width of solvate ionic radius must add water conservancy diversion, so that can contact bigger ion, thereby admits electrolyte itself by water conservancy diversion.The Fan Dewaer stone road width of the sulfide of bismuth is too narrow, has influenced electrolyte and has penetrated wherein, will give the chalkogenide " water conservancy diversion " of bismuth like this, after detailed water conservancy diversion operation is described in.

Electrode material resembles activated carbon and there is no and be mingled with compound, does not just need such water conservancy diversion process, because it does not contain the Fan Dewaersi zone.As mentioned above, the pore surface of activated carbon inside has increased surface area, and hole can be admitted electrolyte, can form electric double layer.

The purity of the selection of material and defect concentration also obviously influence electrode material, and the charge density capacity and the internal resistance of specific inclusion material.Here it is just shows by the efficient of utilizing Fan Dewaer stone road to increase electrode surface area.The impurity in Fan Dewaer stone road, lattice defect, geometry distortion and regional characteristics make it to be difficult to be mingled with again, make the channel surface structure degradation, thereby the electromechanical properties of passage are descended.Therefore, the capacitance electrode material of selecting for use is the prepared high-purity and perfect as far as possible material of unique technology of inventor's exploitation preferably.For this purpose, following monocrystalline growing process is best suited for the chalcogenide material of bismuth.What other technology was made can not be desirable purity and flawless material, uses but can be used as special cooling device.Those skilled in the art can recognize the parameter of critical material and the causality of respective performances.

Be mingled with in the manufacture process of compound in the best, insert in the quartz ampoule by the high purity bismuth (purity 99.999%) and the tellurium (or chalkogenide of alternative) of stoichiometric composition.If needed, to make zone-refine to material before the use.The nonstoichiometry composition, the result produces lattice structure and reaches the n of relevant mis-behave or the material that the p type mixes.Ampoule is evacuated to 10 ^-7MmHg uses inert gas in a small amount again, recharges pressure 10 as argon or reducing gas ^-3MmHg(3～10 are time repeatedly), sealing then.Best with hydrogen, because hydrogen and oxygen reaction during technology can be prevented oxidation, and pass through to lower the vapour pressure of chalkogenide, and reduce its fractional condensation.

In first operation, the high polycrystalline material uniformly of preparation earlier.Be placed on hermetically sealed ampoule in the heating furnace under the room temperature and heating, make its temperature be higher than 5～10 ℃ of the fusing points of material.Heating rate, temperature and reaction time are decided by final compound.The polycrystalline Bi that makes ₂S ₃, Bi ₂Se ₃And Bi ₂Te ₃Reaction condition, for example in table 1.The heating furnace temperature of whole ampoule scope all is controlled at ± 0.5 ℃ in.Because of chalkogenide volatility height, it is very important carefully accurately to control temperature.Can cause the fractional condensation of chalkogenide along the variations in temperature of ampoule length, this fractional condensation then causes nonstoichiometry to become score value.In order to reach temperature control optimum, can use long heating furnace along ampoule length.The available auxiliary heater coil of stove end is to reduce the temperature gradient at furnace outlet place.

The processing conditions of table I polycrystalline material

Processing conditions Bi ₂Te ₃Bi ₂Se ₃Bi ₂S ₃

Be heated to T liquid (℃/h) speed 30 20 15

Heated time (h) 10 15 20

T liquid+℃ following cooldown rate (℃/h) 50 40 35

In last 1 hour of reaction, stir or the vibration ampoule, to keep the mixing fully of component in the ampoule.The ampoule oscillating region was 25～100 weeks, and was fixed on the vibration source by the end with ampoule and realizes.By the present invention, also can expect with any common vibrating device.After the reaction, be with slowly controlled speed cooling ampoule.

In case obtain uniform polycrystalline material, again it further be processed into the chalkogenide monocrystalline of complete flawless bismuth.Can use any known method for monocrystal growth, such as the Bridgman-Stockbarger technique, cut krousky process technology and zone-refine (recrystallization).Particularly zone refining plays a big part on the high-purity monocrystalline of acquisition.

Be preferably in splendid attire and desirable lattice structure, for example make zone-refine in the quartz boat of the seed crystal of the crystal structure of hexagonal crystal system.The suggestion clean room remains on 100 grades.Seed crystal is along the long orientation of boat, and crystal layer is a horizontal direction like this.Entire equipment is answered damping and is isolated with ambient vibration.The placement that also will contact of the stylobate of polycrystalline material with the surface of seed crystal.

Heating furnace comprises two parts, and one along the outer burner hearth of whole stylobate length direction maintenance temperature rising and a fraction of movably narrow melting zone of a heating polycrystalline material.Outer fire box temperature remains on following 35 ℃ of fusing point, and melting zone length is 2～3cm, and temperature remains on above 10 ℃ of polycrystalline material fusing point.Preparing different with polycrystalline material is that according to the first above-mentioned operation, stylobate can be heated to working temperature rapidly.Be positioned at seed crystal and stylobate when the melting zone begins at the interface, and this position be heated to the fusing point of material.Slowly move along the length direction of stylobate in the melting zone again.The speed that move in the melting zone changes with material component, except other technological parameters, has showed typical speed in the table II.The speed that move in the melting zone is an important technical parameters, if too fast, then crystallization is incomplete, can form defective; Cross slowly, then produce layer distortion.The bottom portion of the heat treatment stylobate that contacts with quartz boat is preferably removed before use.

The process conditions of table II hexagonal crystal system crystal growth

Process conditions Bi ₂Te ₃Bi ₂Se ₃Bi ₂S ₃

MP-35 ℃ Mp-35 ℃ Mp-35 ℃ of stylobate temperature

℃ Mp+10 ℃ of melting zone temperature MP+10 ℃ Mp+10

Melting zone rate travel 8mm/ hour 8mm/ hour 3mm/ hour

50 ℃/hour 40 ℃/hour 35 ℃/hour of cooldown rates

Change above-mentioned technical process a little, also can make the crystal of diamond structure.In this case, to use the rhombus seed crystal in the zone refining.In addition, in order to obtain rhomboidan, furnace temperature will remain on following 30 ℃ of fusing point, and the melting zone remains on the fusing point of polycrystalline material.

Preferably use above-mentioned technology growing single-crystal to be mingled with compound, especially the chalkogenide of bismuth is made the monocrystalline electrode structure.For example, in one embodiment of the invention, the electrode of the chalkogenide of the monocrystalline bismuth of manufacturing is a rectangular geometry, long 5mm, wide 4mm and thick between 0.5～1mm.Preferably to allow the plane in crystal Nei Fandewaer stone road perpendicular to one of monocrystal material metallization crystal face.Metallization comprises, as nickel cream is coated on the crystal, forms the metal level of thick 10～20 μ.Metallization provides the excellent electric contact with wafer, and has improved the rigidity of wafer.

Another kind method is to make electrode to the chalcogenide material pulverize of monocrystalline bismuth.Chippy like this material comes easier processing compared with monocrystal material.Can adopt, as ball mill or other lapping device, carry out the crystal attrition process, preferably making every monocrystalline particulate all has about 70 microns of diameter.Under specific circumstances, other mean particle dias may be better.Then, crystal fine particle and suitable compound, they are bonded together.In fact, when the adhesive effect with particulate " gummed " together the time, electric insulation fully mutually between the particulate.Also to select the adhesive material for use according to electrolyte.When using the inertia electrolyte solvent, adhesive preferably contains the aqueous solution of 3% carboxymethyl cellulose, and particulate is mixed in the solution.For other electrolyte, available another kind of gummed mediator for example contains a sub polyethylene prose style free from parallelism of 5% in neutral hexane.The plastic powder mixture mixture that makes is put into electrode die, at room temperature dry then.The geometry of reason mould determining electrode, for example, it is common that disc is used for capacitor, thickness of electrode is between 0.3～1mm.Other electrode geometry also is feasible.

Above-mentioned grinding step produces certain damage and corresponding crystal defective.Yet, because it is very weak to be mingled with the Vander Waals attraction of compound crystal interlayer, so these compounds split along the crystallographic axis of passage easily, and do not have a lot of lens lesions or distortion.

Among the present invention, the inventor has also improved the technical process preferably of the electrode of chalkogenide, activated carbon and the heat treatment graphite material mixture of making bismuth.In this process program, the chalkogenide of bismuth is as Bi ₂Te ₃Scope that can from 0 to 100%.Active carbon material (ACM) also can from 0 to 100% scope and heat treated graphite (HTG) final mixture, account for 0 to 40% scope.Have superior performance, but the higher electrode of cost should contain the chalkogenide of the bismuth of higher proportion, yet have poorer performance and lower-cost electrode should contain the ACM of higher proportion.Therefore, select for use the specific proportioning should be according to the analysis of Cost And Performance.These component adhesives combine as polytetrafluoroethylene (teflon).

If electrode comprises the chalkogenide of bismuth, as Bi ₂Te ₃, just adopt above-mentioned technology to make the monocrystal particulate.The raw material that is used for ACM is cellulose fibre (cellulose fiber).Cellulose fibre heat treatment 2 hours in oxygen-free environment, temperature is 800～950 ℃.Then, in atmospheric steam, under 800～900 ℃, made its activation through 2～3 hours.Then, it is 4～8mm that material is crushed to diameter range, and length is the particle of 0.5mm.This material should have specific area 1300～2500m ²/ g.Heat treated cellulosic fibre material, phosphorus content is 85～90% as a result.

The manufacturing of heat treatment graphite (HTG), to be not more than 2% crystalline graphite sheet initial to contain ash amount.This material is ground, and filter out the particle of maximum gauge with 200 μ m.Then, with these granular materials heat treated in electric furnace, temperature range is 2200～2500 ℃, carries out under the vacuum atmosphere.Preferably vacuum degree is 10 ^-4MmHg does heat treatment.This material will stop time enough in heating furnace, residual content of ashes is reduced to be less than 0.1%.After heat treated, dusty material is sieved with vibrating screen device, obtain the particulate that diameter range is 80～200 μ m.

The adhesive material of selecting for use as teflon, is at first processed in blender, reaches 3～5cm ³/ g's is loose long-pending.Adhesive is added in the dusty material, and its amount is no more than the 20wt% of electrode weight.

As long as be ready to raw material, just can carry out following steps, make the ACM electrode.At first, the chalkogenide powder of monocrystalline bismuth (if containing the words of a bit), heat treated graphite and teflon are put into blender, stir 2～3 minutes, and rotating speed is not less than 4000 rev/mins., add a selected amount of ACM, stirred 2～3 minutes, make material reach loose long-pending 4.3～4.7cm with same speed thereafter ³/ g.A kind of suitable material is to begin with 97% HTG and 3% teflon, adds then that to account for total weight be 80% ACM.

Then, electrode material is pressed onto on the metal substrate, the pressure of used hydraulic press is about 270MPa.The electrode suitable dimensions is 10 * 10 * 0.1cm ³The backing material that is fit to is a nickel foil of having beaten the hole, and the aperture is 0.7～1.0mm, and the spacing in hole is 0.6～0.8mm.Can also punch with other way.The optimum thickness of the substrate of metal is 0.1mm.

After electrode mixture is compressed on the metal substrate, the electrode that obtains is being evacuated to 10 ^-1Make annealing in process in the container of mmHg, 1～2 hour time, temperature is 100～140 ℃.

After the annealing, with suitable electrolyte, as with 28～30% caustic potash aqueous solution impregnated electrode.This electrode will be at room temperature, and pressurization was soaked about 5～10 minutes.

Adopt suitable electrode production process, both comprised that above-mentioned technology also comprises the technical process that other is fit to, and was assembled into following system with electric capacity cooling device of the present invention.With reference to Fig. 1, in the structure 60 of this preferred device, two identical electrodes are preferably the chalkogenide electrode 20 of bismuth, are separated by electrolyte 30.When using the chalkogenide electrode of bismuth, corresponding electrolyte 30 comprises uses the aqueous solution, as containing the LiClO of 1.0M in caustic alkali or the propene carbonate (propylene carbonate) ₄In this case, comprise two layers of non-polypropylene that is made into, every bed thickness 100 μ m, and with a kind of separator that electrolyte soaked into, provide the mechanical support of electrolyte.On the other hand, for different electrode materials, electrolyte also can comprise organic cation, the caustic potash aqueous solution, the monovalent metal sulfate solution that is dissolved with the 1.2M perchlorate in the mixture of dimethoxy-ethane and propene carbonate, or other aqueous solution.Use above-mentioned LiClO ₄Propene carbonate electrolyte will suitably flood the polypropylene separator with electrolyte, and separator is placed between the electrode 20.Because the separator material has increased total internal resistance of device, in the time of therefore with consideration related device parameter, the thickness of separator will be done minimumly as far as possible.Electrode is installed separately with separator, is inserted into the support frame (not shown) again, and is sealed to press type.

As mentioned above, depend on the electrode material and the electrolyte of cooling device, material may need " water conservancy diversion ", and particularly, some are mingled with in addition water conservancy diversion of compound, allows electrolyte infiltrate Fan Dewaer stone road, forms the electric charge bilayer of channel surface.Though the chalkogenide electric conductivity of bismuth is good,, be a kind of need the water conservancy diversion process be mingled with the section bar material.Therefore, will narrate water conservancy diversion below, " water conservancy diversion " is a kind of course of processing, by being activated at the electrolyte (and ion) in the Fan Dewaer stone road, to make things convenient for the electrolyte access way.Though what describe is water conservancy diversion technical process to this material, it should be understood that same technical process also can use other materials.

With reference to Fig. 2 A, showed when the water conservancy diversion process begins to have the sulfide electrode 20a of two bismuths, the electric capacity cooling device 60 of 20b here.The Fan Dewaer stone road 70a of electrode, the size of 70b are for convenient understanding is had a mind to exaggerative.Should recall, each electrode all has quantity about 10 ⁶～10 ⁷Individual such passage.Between two electrodes, adorning with LiClO ₄Electrolyte 30 for base.In the water conservancy diversion process, allow power supply 40 supply with a voltage, this voltage is greater than faraday's current potential that cation is inserted, thereby voltage depends on the component and the employed electrolyte of the electrode material of particular device.The combination of given a kind of electrode of selecting for use especially and electrolyte, those skilled in the art is clear, by the standard chart of material series and faraday's voltage, just can determine corresponding faraday's current potential.

Electrode carries out at the beginning of the water conservancy diversion, and when device being added a voltage that is higher than faraday's current potential, the electrode 20b that is connected to positive source assembles positive surface charge.This kind positive surface charge is equally also being assembled on the surface of the Fan Dewaer stone road 70b of electrode.Corresponding, no matter macro surface, negative surface charge is all assembled on the surface of Fan Dewaer stone road 70a that still is connected to the electrode 20a of power cathode.

In order to adapt to electric charge and Energy distribution, also because its ratio of ionic radii Fan Dewaersi width of channel is little a lot, in the distribution of this surface charge of response, free Li ⁺Ion 72 just inserts among the electronegative electrode 20a easily.In addition, the Li of solvate ⁺76 in complex compound shift to positively charged electrode surface.Positively charged electrode has only 3～4A Fan Dewaer stone road 70b of wide (existing before the water conservancy diversion technical process), to penetrating ClO wherein - ₄Complex compound is a size.But in fact, with free Li ⁺Ion works the Li that is transferred to the solvate in electrode surface and the electrode channel together ⁺Complex compound can penetrate the wide by 3～4 of electronegative electrode slightly

Passage 70a in.As a result, the Li of this solvate ⁺Complex compound can make them partly enter electronegative electrode channel to expand a little.

In order to make the Li of solvate ⁺Complex compound penetrates the electrode 20b on opposite, so, the polarity reversal of power supply be come.Then, the surface charge of gathering distributes also conversely, and originally positively charged electrode is assembled negative surface charge now, and attracts Li freely ⁺The complex compound 74 of ion 72 and solvate.Free Li ⁺Ion 72 is easy to insert these passages, and the complex compound 74 of solvate just partly enters corresponding Fan Dewaer stone road, thereby only expands this passage slightly.

With reference to Fig. 2 B, the repetition of this process of polarity of voltage conversion, each Fan Dewaersi width of channel of

expansion electrode

20a, 20b gradually.Whole such process, according to initial added voltage, this voltage also will increase, and strengthens whereby to attract ion and electrolyte to go to Fan Dewaer stone road.In the interstage of water conservancy diversion process, as depicted in FIG., the Li of solvate ⁺Complex compound 74 and free Li ⁺Ion may penetrate broadening fully, show the passage 70b of electronegative electrode 20b usually.Yet, have greater than solvate Li ⁺The ClO of the sort of solvate of complex compound size - ₄Complex compound still can not penetrate usually the passage of positively charged electrode 70a fully.

The water conservancy diversion process end of term, shown in Fig. 2 C, the ClO of solvate - ₄The Li of complex compound 76 and solvate ⁺Complex compound 74 all can penetrate Fan Dewaer stone road 70a, the 70b of electrode 20a, 20b.Shown in Fig. 2 D, at this moment, be electroneutral electrolyte and (comprise ClO - ₄ Complex compound 76 and Li ⁺Complex compound 74) all can penetrate Fan Dewaer stone road, and the interface that spreads all over the electrode in each Fan Dewaer stone road and electrolyte has formed the electric double layer of

electric charge

86,82 and 84,86.Similar therewith, this situation also occurs in the electrode surface of macroscopic view.The electrolyte permeability that spreads all over each passage of crystal is the basis that reaches surprising charge density, and consequently the present invention has reached the effect of cooling.

The water conservancy diversion degree that the electrolyte that requires in the Fan Dewaer stone road of electrode to reach penetrates, key is the component and the electrolyte of employed special electrodes material.The radius of the electrode Fan Dewaersi width of channel when not standing any water conservancy diversion process and the complex compound of electrolyte internal solvent thing decides needed water conservancy diversion degree.To bigger complex compound radius and less Fan Dewaer stone road width, need the long water conservancy diversion time.For electrode material Bi ₂Te ₃With with LiClO ₄Be the electrolyte of base, water conservancy diversion preferably has the circulation of 20 water conservancy diversion, and each circulated about 30 minutes and each circulation all will be reversed polarity of electrode.Yet,, can adjust this water conservancy diversion cycle-index to the requirement of special capacitor element.With regard to less water conservancy diversion cycle-index, only require that then the electrolyte that reaches than low degree infiltrates in passage, therewith corresponding meeting is lower double layer capacity amount.Like this, for giving fixed electrode,, then should make water conservancy diversion to greatest extent for reaching the electric capacity of maximum possible.Those skilled in the art can recognize, given electrode and electrolyte liquor combination and charge density are admitted index, can rule of thumb determine best water conservancy diversion measure.

The present invention gives another water conservancy diversion technical process of deciding within the scope, and in for example above-mentioned technical process, the polarity of voltage remains unchanged, or utilizes charging and discharging process to come broadening Fan Dewaer stone road.In such process,, the time with one-period, between electrode, apply a voltage that is higher than faraday's current potential according to above-mentioned method.Then, allow capacitor discharge by suitable load.If the polarity of voltage of this process remains unchanged, if or changing voltage polarity not during the previous described water conservancy diversion process, so, have the electrode just can not its passage of broadening, this depends on the component of electrode material and electrolyte.Such as, in the constant water conservancy diversion process of polarity of voltage, use Bi ₂Te ₃Electrode and with LiClO ₄Be the electrolyte of base, then have freely Li with solvate with the electrode of negative polarity ⁺Complex compound (thereby admitting electrolyte) inserts.But the electrode of positive polarity never is beneficial to the free Li that sets about opening up the crystal passage ⁺Ion and complex compound, like this, the ClO of solvate - ₄Complex compound just can not expanded those passages to admit electrolyte.As a result, the electrode of positive polarity can not form the Fan Dewaersi surface of having expanded.

The fact of particular importance is that the water conservancy diversion process does not have any significant deformation or distortion to the crystal face of stratification crystalline electrode material.Crystal face deformation degree is relevant with other character that original purity, defect concentration and the growth course of electrode material cause.The genetic defects of crystal is less, its result, and water conservancy diversion also only causes decimal crystal face deformation lattice point.When water conservancy diversion finished, crystal face only slightly a bit or not distorted, and the surface, Fan Dewaer stone road of electrode is uniform and stable.In addition, the internal resistance of material still keeps very low.These situations are for the cooling device of the present invention adiabatic discharge mechanism that exists of relying provides assurance.Also have material facts to be, after electrolyte was admitted in the Fan Dewaer stone road of water conservancy diversion technical process institute broadening, passage can not be withdrawn into original width.

Should emphasize, another kind of material, resembling the mixture that comprises activated carbon also is the electrode material that is fit to, and need not the water conservancy diversion technical process.

Referring now to Fig. 3.Cooling device of the present invention is by following configuration effort.Capacitor structure 60 is by calorimeter 35 or any suitable insulator and the isolation of environment heat.By, for example switch 62 is in parallel with device and charging, discharge circuit.This circuit is outside calorimeter 35.Charging circuit comprises power supply 40 and is used to limit the electric control element 64 of power supply to the double-deck charging rate of capacitor element, as demand limiter.Discharge circuit comprises suitable load 65, as lead, resistor or other load elements.Preferably, select load elements according to density for the electric charge accumulation of the capacitor element that reaches the highest as far as possible velocity of discharge.Thermocouple device 66 can be positioned near the cooling device 60, and in order to measure cooling effect, such thermocouple device can comprise the measuring instrument 68 that is used to show the cooling effect detection usually.

During work, capacitance structure 60 is by the suitable control of switch 62, and at first with power connection, at this moment, capacitance structure provides the bilayer of charging.Demand limiter 64 produces " trickle charge " effects, with this speed of controlling charging work, makes enough slow of its course of work, in order that make this device can keep the temperature state such as grade.The device that utilizes suitable resistor or transistor formation is as demand limiter.In case capacitance structure has accumulated specific charge density, master cock 62 just makes the capacitance structure discharge by load.Because this capacitance structure has very high charge density and very low internal resistance, and the most handy low load resistance, so this structure can be to be bordering on the speed discharge of adiabatci condition.As a result, at the discharge duration of work, the temperature of capacitance structure descends.The circulation of charge and discharge process is carried out, and causes the accumulation of cooling effect.

According to thermodynamic principles, the thermal insulation that the mechanism of cooling is produced when resulting from the capacitance structure discharge

Increase.As the requirement of the second law of thermodynamics,

Increase can cause decrease of temperature.Isothermal electric capacity charging process causes orderly, with accordingly

Decline, in fact be exactly that discharge process discharges Reduce.According to this phenomenon, should be taken into account that it is more effective that the electrode material that shows high order degree is used in the material that will relatively hang down order degree in the cooling device.Here so-called " order degree " is meant and describes crystal purity, defect concentration, the uniformity and other influences about structure and electrical property.Such as, be appreciated that the monocrystalline electrode structure can provide bigger than polycrystalline electrodes structure

Change reduce with corresponding temperature.

Proved the 20mm size, with Bi ₂Te ₃, LiClO ₄Cooling device for base discharges and recharges the cycle cooling effect that reaches (each cycle comprises once charging and the process of once discharging) 0.5～0.7 ℃ of reduction each time.So significant cooling effect is also with making circulative accumulation continuously, and till having proved that can proceed to electrolyte condenses.Preferably finish 1 second of the stage that discharges and recharges of given each circulation.Known that the superior electric charge of this device admits capacity and low internal resistance, strengthened every cubic centimetre of cooling effect process-be device charging capacity between 30～100 farads, and the device internal resistance has been approximately near 0.02 Ω/cm ²So extremely low internal resistance obtains high-power ability when the capacitor discharge is provided.In theory, it is 1000 farads every cubic centimetre that the monocrystalline capacitance structure of the chalkogenide of pure flawless bismuth will demonstrate capacitance, and the higher velocity of discharge is arranged.

Must understand that electric capacity cooling device of the present invention also can use other material and electrolyte, and still can reach cooling effect.Yet the performance of device is to be realized by selected especially combination of materials and electrolyte.Such as comprising active carbon electrode, and use and form as electrolyte, still can reach the cooling device of cooling effect, but its efficient outline is less than comprising the device of being made up of the chalkogenide electrode of bismuth as sulfuric acid.Consider with Bi ₂Te ₃LiClO ₄Be enough to cooling degree that electrolyte is solidified for the cooling device of base can reach, therefore, can use other the subzero electrolyte series that is adapted to electrode material.In theory, for example use solidifying point be-60 ℃ propene carbonate as electrolyte, this will obtain the ability of big cooling range.

The inventor recognizes, the cooling capacity that all can use electric capacity cooling device of the present invention to provide in numerous application scenarios, and the unnumbered application of solid-state cooling device all is better than traditional condensing type cooling device.These application comprise, as electronic component, medicine equipment, fibre system, food refrigeration equipment, chemical analysis device and the cooling that expands to many other systems, have the characteristics that volume is little, in light weight, power is low or be not subjected to materials limitations (replacement fluorine chlorine methane series system is exactly this situation) invariably.

In addition, the embodiment of the other materials of cooling device, water conservancy diversion process, working method and application should be included in the spiritual scope of the present invention.

Claims

1, a kind of thermoelectric device, comprise two electrodes that separate by electrolyte, each electrode is made up of crystalline material, it is characterized in that there is Fan Dewaer stone road in crystalline material, receivability electrolyte in it, when applying voltage between two electrodes, the interface of passage and electrolyte forms the electric charge bilayer, device demonstrates temperature and descends in two cooling stages, these two stage cooling procedures are included in and apply voltage between the electrode, form bilayer with this,, make double-deck discharge by load with a load voltage of transformation.

2, thermoelectric device as claimed in claim 1 is characterized in that, said crystalline material is the chalkogenide of bismuth.

3, thermoelectric device as claimed in claim 1 is characterized in that, said crystalline material comprises solid solution Bi _X(Te _3-ySe _y), wherein x is 1 or 2, y is 0～3.

4, as claim 1,2 or 3 described thermoelectric devices, it is characterized in that each of said two electrodes all is made of the monocrystalline of crystalline material.

As claim 1,2 or 3 described thermoelectric devices, it is characterized in that 5, each of said two electrodes all is made of the monocrystal particulate of said crystalline material.

As claim 1 or 3 described thermoelectric devices, it is characterized in that 6, said electrolyte comprises the LiClO of dissolving 1.0M in the propene carbonate ₄

As claim 1 or 3 described thermoelectric devices, it is characterized in that 7, said electrolyte comprises the organic cation of the perchlorate of dissolving 1.2M in the mixture of dimethoxy-ethane and propene carbonate.

8, thermoelectric device as claimed in claim 1 is characterized in that, also comprises the power supply of said voltage, controls the device of said voltage application and is used to provide the resistive device of said load.

9, thermoelectric device as claimed in claim 8 is characterized in that, controls said voltage application, makes described double-deck isothermal charging.

10, thermoelectric device as claimed in claim 9 is characterized in that, said bilayer is adiabatic by said load discharge.

11, thermoelectric device as claimed in claim 1 or 2 is characterized in that, makes said Fan Dewaer stone road be suitable for admitting electrolyte by the water conservancy diversion process, and the water conservancy diversion process comprises makes electrolyte insert Fan Dewaer stone road.

12, thermoelectric device as claimed in claim 11 is characterized in that, by apply water conservancy diversion voltage between said electrode, produces said being mingled with, and it is enough high that said water conservancy diversion voltage is wanted, and can penetrate said passage with the ion fluor-complex of realizing solvate.

13, thermoelectric device as claimed in claim 12 is characterized in that, said water conservancy diversion voltage reverse periodically between electrode.

14, thermoelectric device as claimed in claim 13 is characterized in that, said water conservancy diversion voltage is increased in time, is enough to produce faradic process electrolyte from first voltage, is enough to realize that to second voltage electrolyte penetrates said passage.

15, thermoelectric device as claimed in claim 14 is characterized in that, applies water conservancy diversion voltage about 600 minutes for said electrode.

16, thermoelectric device as claimed in claim 15 is characterized in that, said water conservancy diversion voltage is polarity of conversion in per 30 minutes approximately.

17, a kind of thermoelectric device that is used for cooling object, this device comprise having two electrodes, and with the capacitor element of said object thermal coupling, when capacitor element repeats to discharge and recharge, provide a kind of cooling effect.

18, thermoelectric device as claimed in claim 17 is characterized in that, said charging is an isothermal, and said discharge is adiabatic.

19, thermoelectric device as claimed in claim 18 is characterized in that, said capacitor comprises a double layer capacity device.

20, thermoelectric device as claimed in claim 19 is characterized in that, said capacitor comprises electrolytic capacitor.

21, thermoelectric device as claimed in claim 19 is characterized in that, each electrode of said capacitor is that the crystalline material of feature constitutes by there being Fan Dewaer stone road.

22, thermoelectric device as claimed in claim 19 is characterized in that, each electrode of said capacitor all comprises porous material.

23, thermoelectric device as claimed in claim 22 is characterized in that, each electrode of said capacitor all comprises activated carbon.

24, thermoelectric device as claimed in claim 21 is characterized in that, said crystalline material comprises the chalcogenide of bismuth.

25, thermoelectric device as claimed in claim 23 is characterized in that, each electrode of said capacitor comprises (Bi ₂Te ₃) _X(Carbon) _1-X, wherein x is 0～1.

26, a kind of thermoelectric device, comprise two electrodes that separate by electrolyte, each electrode all is made of porous material, when applying voltage between two electrodes, can form the electric charge bilayer at the interface of porous material, in two stage cooling procedures, this device demonstrates temperature and descends, and two cooling stages apply voltage between electrode, forms double-deck whereby, and use the load voltage of transformation, make double-deck discharge by load.

27, thermoelectric device as claimed in claim 26 is characterized in that, said porous material comprises compound, activated carbon and the heat treated graphite of the chalkogenide of bismuth.

28, thermoelectric device as claimed in claim 27 is characterized in that, said electrolyte comprises sulfuric acid.

29, as claim 1 or 26 described thermoelectric devices, it is characterized in that, control said voltage and apply, make said double-deck isothermal charging.

30, thermoelectric device as claimed in claim 29 is characterized in that, said double-deck discharge is adiabatic.

As claim 1 or 26 described thermoelectric devices, it is characterized in that 31, said device demonstrates by repeating the temperature decline that said two stage cooling procedures produce accumulation.

32, thermoelectric device as claimed in claim 31 is characterized in that, once described repetition approximately takes place each second.