JP5855876B2 - Power generation system - Google Patents

Description

  The present invention relates to a power generation system.

  Conventionally, in internal combustion engines such as automobile engines, heat exchangers such as boilers and air conditioning equipment, electric engines such as generators and motors, and various energy utilization devices such as light emitting devices such as lighting, for example, as exhaust heat, light, etc. A lot of thermal energy is released and lost.

  In recent years, from the viewpoint of energy saving, it is required to recover the released thermal energy and reuse it as an energy source. As such a method, thermoelectric conversion power generation using a pyroelectric element is known. Yes.

  Specifically, for example, a heating source that increases the temperature of each of the plurality of pyroelectric elements, a cooling source that decreases the temperature of each of the pyroelectric elements, a heating source and a cooling source, and / or a pyroelectric element A method of taking out DC power or AC power from a pyroelectric element by periodically raising and lowering the temperature of the pyroelectric element by a heating source and a cooling source using a power generation device including a moving unit that moves the element, It has been proposed (see, for example, Patent Document 1).

JP-A-11-332266

  On the other hand, such a power generation method is required to generate power with even better efficiency.

  An object of the present invention is to provide a power generation system capable of generating power with higher efficiency.

  To achieve the above object, the power generation system of the present invention comprises a heat source whose temperature rises and falls over time, an electrically polarizable matrix, and a dispersed material having a specific heat capacity lower than the specific heat capacity of the matrix, It is characterized by comprising a first device that is electrically polarized by a temperature change of a heat source, and a second device for taking out electric power from the first device.

  In the power generation system of the present invention, it is preferable that the dispersion material is in a reduced state at 200 to 500 ° C.

  According to the power generation system of the present invention, since the first device made of the electrically polarizable matrix and the dispersed material having the specific heat capacity lower than the specific heat capacity of the matrix is used, the device that can be simply electrically polarized is used as the first device. Compared with the case of using, it is possible to generate power with superior efficiency.

FIG. 1 is a schematic configuration diagram showing an embodiment of a power generation system of the present invention. FIG. 2 is a schematic configuration diagram showing an embodiment of the first device shown in FIG. FIG. 3 is a schematic configuration diagram showing another embodiment of the first device shown in FIG. FIG. 4 is a schematic configuration diagram showing an embodiment in which the power generation system of the present invention is mounted on a vehicle. FIG. 5 is an enlarged view of a main part of the power generation system shown in FIG. FIG. 6 is a graph showing the relationship between the generated voltage and the temperature change in the first embodiment. FIG. 7 is a graph showing the relationship between the generated voltage and the temperature change in the second embodiment. FIG. 7 is a graph showing the relationship between the generated voltage and the temperature change in Comparative Example 1.

  FIG. 1 is a schematic configuration diagram showing an embodiment of a power generation system of the present invention.

  In FIG. 1, a power generation system 1 includes a heat source 2 whose temperature rises and falls over time, a first device 3 that is electrically polarized by a temperature change of the heat source 2, and a second device 4 that extracts electric power from the first device 3. It has.

  The heat source 2 is not particularly limited as long as the temperature rises and falls over time, and examples thereof include various energy utilization devices such as an internal combustion engine and a light emitting device.

  An internal combustion engine is a device that outputs power, for example, for a vehicle. For example, a single cylinder type or a multi-cylinder type is adopted, and a multi-cycle type (for example, a 2-cycle type, a 4-cycle type) is used in each cylinder. System, 6-cycle system, etc.).

  In such an internal combustion engine, pistons are repeatedly moved up and down in each cylinder. For example, in a 4-cycle system, an intake process, a compression process, an explosion process, an exhaust process, and the like are sequentially performed, and fuel is discharged. It is burned and power is output.

  In such an internal combustion engine, in the exhaust process, high-temperature exhaust gas is exhausted through an exhaust gas pipe. At this time, the exhaust gas pipe transfers the thermal energy of the exhaust gas, and the temperature rises.

  On the other hand, in other processes (steps excluding the exhaust process), the amount of exhaust gas in the exhaust gas pipe is reduced, so the heat energy transferred by the exhaust gas pipe is reduced, and as a result, the temperature of the exhaust gas pipe decreases. To do.

  As described above, the temperature of the internal combustion engine rises in the exhaust process and falls in the intake process, the compression process, and the explosion process, that is, rises and falls over time.

  In particular, since each of the above steps is periodically repeated sequentially according to the piston cycle, the exhaust gas pipe of each cylinder in the internal combustion engine periodically changes in temperature with the repetition cycle of each of the above steps. More specifically, the high temperature state and the low temperature state are periodically repeated.

  When the light emitting device is turned on (light emission), for example, the temperature rises due to thermal energy of light such as infrared rays and visible light, and when the light is turned off, the temperature drops. Therefore, the temperature of the light emitting device increases and decreases over time by turning on (emitting) and turning off over time.

  In particular, for example, when the light-emitting device is a light-emitting device (blinking (flashing) type light-emitting device) in which lighting is turned on and off intermittently over time, the light-emitting device is turned on (light-emitting). Due to the thermal energy of the light, a temperature change periodically, more specifically, a high temperature state and a low temperature state are periodically repeated.

  Moreover, as the heat source 2, for example, a plurality of heat sources can be provided, and a temperature change can be caused by switching between the plurality of heat sources.

  More specifically, for example, two heat sources, a low-temperature heat source (such as a coolant) and a high-temperature heat source (eg, a heating material) having a higher temperature than the low-temperature heat source, are prepared as the heat source. A mode in which a low-temperature heat source and a high-temperature heat source are alternately switched is used.

  Thereby, the temperature as a heat source can be raised or lowered with time, and in particular, the temperature can be periodically changed by periodically switching the low-temperature heat source and the high-temperature heat source.

  Although it does not restrict | limit especially as the heat source 2 provided with the several heat source which can be switched, For example, the high temperature air provided with the low temperature air supply system for combustion, the thermal storage heat exchanger, the high temperature gas exhaust system, and the supply / exhaust switching valve Combustion furnace (for example, a high-temperature gas generator described in Republished No. 96-5474), for example, a seawater exchange device (hydrogen storage alloy actuator-type seawater exchange device) using a high-temperature heat source, a low-temperature heat source, and a hydrogen storage alloy Is mentioned.

  As these heat sources 2, the said heat source can be used individually or in combination with 2 or more types.

  The heat source 2 is preferably a heat source whose temperature changes periodically with time.

  The heat source 2 is preferably an internal combustion engine.

  The first device 3 is a device that is electrically polarized in accordance with a temperature change of the heat source 2.

  The electric polarization referred to here is a phenomenon in which a potential difference occurs due to dielectric polarization due to displacement of positive and negative ions due to crystal distortion, such as a piezo effect and / or a phenomenon in which a dielectric constant changes due to a temperature change and a potential difference occurs, such as pyroelectricity. It is defined as a phenomenon in which an electromotive force is generated in a material such as an effect and / or a phenomenon in which an electric charge is biased due to a temperature change, a temperature gradient, or the like, for example, a Seebeck effect.

  More specifically, examples of the first device 3 include a device that is electrically polarized by a piezo effect, a device that is electrically polarized by a pyroelectric effect, and a device that is electrically polarized by a Seebeck effect.

  The piezo effect is an effect (phenomenon) in which when a stress or strain is applied, it is electrically polarized according to the magnitude of the stress or strain.

  The first device 3 that is electrically polarized by such a piezo effect is not particularly limited, and for example, a known piezo element (piezoelectric element) such as a thin film type or a bulk type can be used.

  When a piezo element is used as the first device 3, the piezo element is, for example, close to the heat source 2 in a state where the periphery thereof is fixed by a fixing member and volume expansion is suppressed, or will be described later. It arrange | positions so that it may contact via an electrode. The fixing member is not particularly limited, and for example, a second device 4 (for example, an electrode) described later can be used.

  In such a case, the piezo element is heated or cooled by the temperature change of the heat source 2 over time, and thereby expands or contracts.

  At this time, since the volume expansion of the piezo element is suppressed by the fixing member, the piezo element is pressed by the fixing member and is electrically polarized by the piezo effect (piezoelectric effect) or phase transformation near the Curie point. . Thereby, although mentioned later in detail, electric power is taken out from the thermoelectric conversion element via the second device 4.

  In addition, such a piezo element is normally maintained in a heated state or a cooled state, and when its temperature becomes constant (that is, a constant volume), the electric polarization is neutralized, and then cooled or heated, Again, it is electrically polarized.

  Therefore, as described above, when the temperature of the heat source 2 periodically changes and the high temperature state and the low temperature state are periodically repeated, the piezo element is periodically heated and cooled. Electrical polarization and its neutralization are repeated periodically.

  As a result, electric power is extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates periodically by the second device 4 described later.

  The pyroelectric effect is, for example, an effect (phenomenon) in which the insulator is electrically polarized in accordance with a change in temperature when the insulator (dielectric) is heated and cooled, and includes the first effect and the second effect. It is out.

  The first effect is an effect in which, when the insulator is heated and cooled, it spontaneously polarizes due to the temperature change and generates a charge on the surface of the insulator.

  In addition, the second effect is an effect that pressure deformation occurs in the crystal structure due to temperature changes during heating and cooling of the insulator, and piezoelectric polarization occurs due to stress or strain applied to the crystal structure (piezo effect, piezoelectric effect). ).

  As a device that is electrically polarized by such a pyroelectric effect, a composite element (hereinafter referred to as a pyroelectric composite element) obtained using a known pyroelectric element material as a matrix material can be used, as will be described in detail later.

  When a pyroelectric composite element (described later) is used as the first device 3, the pyroelectric composite element (described later) contacts, for example, the heat source 2 through proximity or an electrode described later. Arranged.

  In such a case, the pyroelectric composite element (described later) is heated or cooled by the temperature change of the heat source 2 over time, and the electric polarization is caused by the pyroelectric effect (including the first effect and the second effect). To do. Thereby, as will be described in detail later, power is taken out from the pyroelectric composite element (described later) through the second device 4.

  Further, such a pyroelectric composite element (described later) is usually maintained in a heated state or a cooled state, and when its temperature becomes constant, the electric polarization is neutralized, and then cooled or heated, Again, it is electrically polarized.

  Therefore, as described above, when the temperature of the heat source 2 periodically changes and the high temperature state and the low temperature state are periodically repeated, the pyroelectric composite element (described later) is heated and cooled periodically and repeatedly. Therefore, the electric polarization of the pyroelectric composite element (described later) and its neutralization are repeated periodically.

  As a result, electric power is extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates periodically by the second device 4 described later.

  The Seebeck effect is, for example, an effect (phenomenon) in which an electromotive force is generated in a metal or semiconductor according to the temperature difference when a temperature difference is generated between both ends of the metal or semiconductor.

  As a device that electrically polarizes due to the Seebeck effect, a composite element obtained by using a known thermoelectric conversion element material as a matrix material (hereinafter referred to as a thermoelectric conversion composite element) can be used as will be described in detail later.

  When a thermoelectric conversion composite element (described later) is used as the first device 3, for example, one end of the thermoelectric conversion composite element (described later) is close to the heat source 2 or described later. And the other end is arranged so as to be separated from the heat source 2.

  In such a case, only one end portion of the thermoelectric conversion system composite element (described later) is heated or cooled by the temperature change of the heat source 2 over time, and both ends of the thermoelectric conversion system composite element (described later). A temperature difference occurs between the one side end and the other side end. At this time, an electromotive force is generated in the thermoelectric conversion composite element (described later) due to the Seebeck effect. Thereby, although mentioned later in detail, electric power is taken out from the thermoelectric conversion system composite element (described later) through the second device 4.

  In addition, when such a thermoelectric conversion composite element (described later) has a large temperature difference at both ends, the electromotive force becomes high and high power can be taken out. The electromotive force is reduced and the extracted power is reduced.

  Therefore, as described above, when the temperature of the heat source 2 periodically changes and the high temperature state and the low temperature state are periodically repeated, the temperature at one end of the thermoelectric conversion composite element (described later) is: Since it rises and falls periodically, the magnitude of the electromotive force rises and falls periodically accordingly.

  As a result, electric power is extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates periodically by the second device 4 described later.

  These first devices 3 can be used alone or in combination of two or more.

  FIG. 2 is a schematic configuration diagram showing an embodiment of the first device shown in FIG.

  As shown in FIG. 2, the first device 3 can be used in a stacked arrangement, for example.

  In such a case, a second device 4 (for example, an electrode, a conductive wire, etc.) described later is interposed between the plurality of first devices 3 (preferably pyroelectric composite elements (described later)), thereby The first devices 3 are connected so as to be electrically in series during the electric polarization.

  And the laminated body of the 1st device 3 obtained in this way is arrange | positioned so that it may contact or adjoin to the heat source 2, as shown in FIG. 1, and each 1st device 3 laminated | stacked is heated or cooled simultaneously. To do.

  As a result, a plurality of first devices 3 can be electrically polarized at the same time, and they can be electrically connected in series. As a result, compared with the case where the first device 3 is used alone (as a single layer), a larger electric power is required. It can be taken out.

  FIG. 3 is a schematic configuration diagram showing another embodiment of the first device shown in FIG.

  As shown in FIG. 3, the first device 3 can also be used, for example, arranged in the same plane.

  In such a case, the plurality of first devices 3 are connected to each other by a second device 4 (for example, an electrode, a conductive wire, etc.) to be electrically connected in series during electric polarization.

  Then, as shown in FIG. 1, the plurality of first devices 3 arranged in this manner are arranged so as to be in contact with or close to the heat source 2, and the first devices 3 arranged in alignment are heated simultaneously. Or cool.

  Thereby, the several 1st device 3 can be electrically polarized simultaneously, and they can be electrically connected in series, As a result, big electric power can be taken out compared with the case where the 1st device 3 is used independently.

  At this time, for example, when the first device 3 is a pyroelectric composite element (described later), a thermoelectric conversion composite element (described later) made of a p-type semiconductor, or a thermoelectric conversion composite made of an n-type semiconductor. In the case where only the element (described later) is used, each first device 3 is in contact with or close to the heat source 2, and either one of them is a positive electrode or a negative electrode, and the other side separated from the heat source 2 is either a negative electrode or a positive electrode. It is electrically polarized so as to be (see FIG. 3A).

  Therefore, in such a case, the side that is in contact with or close to the heat source 2 of the first device 3 and the side that is separated from the heat source 2 of the other first device 3 are electrically connected.

  On the other hand, for example, as the first device 3, a thermoelectric conversion composite element (described later) made of a p-type semiconductor and a thermoelectric conversion composite element (described later) made of an n-type semiconductor are used and arranged alternately. Since a thermoelectric conversion composite element (described later) made of a p-type semiconductor and a thermoelectric conversion composite element (described later) made of an n-type semiconductor are electrically polarized in opposite directions, the heat source 2 of each first device 3 On one side in contact or proximity, the positive and negative electrodes are alternately aligned.

  Therefore, in such a case, the side that is in contact with or close to the heat source 2 of the first device 3 is electrically connected to the side that is in contact with or close to the heat source 2 of the other first device 3. The side of the one device 3 that is separated from the heat source 2 and the side of the other first device 3 that is separated from the heat source 2 are electrically connected (see FIG. 3B).

  In FIG. 1, the second device 4 is provided to extract power from the first device 3.

  More specifically, the second device 4 is not particularly limited, but, for example, two electrodes (for example, a copper electrode, a silver electrode, etc.) disposed opposite to each other with the first device 3 interposed therebetween, for example, ., And the like, and are electrically connected to the first device 3.

  In the power generation system 1 shown in FIG. 1, the second device 4 is electrically connected sequentially to the booster 5, the AC / DC converter (AC-DC converter) 6, and the battery 7.

  In order to generate electric power using such a power generation system 1, for example, first, the temperature of the heat source 2 is changed over time, preferably periodically, and the first device 3 described above according to the temperature change. Is preferably electrically polarized periodically. Thereafter, the electric power is taken out as a waveform (for example, alternating current, pulsating current, etc.) that periodically fluctuates according to the periodic electric polarization of the first device 3 through the second device 4.

  In such a thermoelectric system 1, the temperature of the heat source 2 is, for example, 500 to 1200 ° C., preferably 700 to 900 ° C. in the high temperature state, and the temperature in the low temperature state is lower than the temperature in the above high temperature state. More specifically, for example, 200 to 800 ° C., preferably 200 to 500 ° C., and the temperature difference between the high temperature state and the low temperature state is, for example, 10 to 600 ° C., preferably 20 to 500 ° C. is there.

  Moreover, the repetition period of these high temperature states and low temperature states is, for example, 10 to 400 cycles / second, preferably 30 to 100 cycles / second.

  Then, the electric power extracted by the power generation system 1 in this manner is boosted in a state of a waveform (for example, alternating current, pulsating current) that periodically varies in the booster 5 connected to the second device 4. As the booster 5, a booster capable of boosting AC voltage with excellent efficiency by a simple configuration using, for example, a coil and a capacitor is used.

  Next, the electric power boosted by the booster 5 is converted into a DC voltage by the AC / DC converter 6 and then stored in the battery 7.

  According to such a power generation system 1, since the heat source 2 whose temperature rises and falls with time is used, it is possible to take out a fluctuating voltage (for example, AC voltage), and as a result, take it out as a constant voltage (DC voltage), Compared to the case of conversion by a DC-DC converter, the voltage can be boosted with superior efficiency and stored.

  In addition, if the heat source 2 is a heat source that periodically changes in temperature, electric power can be extracted as a waveform that periodically fluctuates, and as a result, it can be boosted and stored with higher efficiency.

  FIG. 4 is a schematic configuration diagram showing an embodiment in which the power generation system of the present invention is mounted on a vehicle.

  In FIG. 4, the automobile 10 includes an internal combustion engine 11, a catalyst mounting portion 12, an exhaust pipe 13, a muffler 14, and a discharge pipe 15.

  The internal combustion engine 11 includes an engine 16 and an exhaust manifold 17.

  The engine 16 is a four-cylinder four-cycle engine, and an upstream end portion of a branch pipe 18 (described later) of the exhaust manifold 17 is connected to each cylinder.

  The exhaust manifold 17 is an exhaust manifold provided for converging exhaust gas exhausted from each cylinder of the engine 16, and a plurality of (four) branch pipes 18 (these are connected to each cylinder of the engine 16. 4 are referred to as the branch pipe 18a, the branch pipe 18b, the branch pipe 18c, and the branch pipe 18d in order from the upper side of FIG. 4), and each branch pipe on the downstream side of the branch pipe 18. And an air collecting tube 19 that integrates 18 into one.

  In such an exhaust manifold 17, the upstream end portion of the branch portion 18 is connected to each cylinder of the engine 16, and the downstream end portion of the branch pipe 18 and the upstream end portion of the air collecting pipe 19 are connected to each other. It is connected. Further, the downstream end of the air collecting pipe 19 is connected to the upstream end of the catalyst mounting portion 12.

The catalyst mounting unit 12 includes, for example, a catalyst carrier and a catalyst coated on the carrier, and hydrocarbons (HC), nitrogen oxides (NO _x ) contained in exhaust gas discharged from the internal combustion engine 11, In order to purify harmful components such as carbon monoxide (CO), it is connected to the downstream end of the internal combustion engine 11 (exhaust manifold 17).

  The exhaust pipe 13 is provided to guide the exhaust gas purified in the catalyst mounting portion 12 to the muffler 14. The upstream end is connected to the catalyst mounting portion 12 and the downstream end is the muffler 14. It is connected to the.

  The muffler 14 is provided to silence noise generated in the engine 16 (in particular, an explosion process), and an upstream end thereof is connected to a downstream end of the exhaust pipe 13. The downstream end of the muffler 14 is connected to the upstream end of the discharge pipe 15.

  The exhaust pipe 15 is provided to discharge exhaust gas that has been exhausted from the engine 16 and sequentially passes through the exhaust manifold 17, the catalyst mounting portion 12, the exhaust pipe 13, and the muffler 14, and has been purified and silenced. The upstream end is connected to the downstream end of the muffler 14, and the downstream end is open to the outside air.

  The automobile 10 is equipped with the power generation system 1 as shown by a dotted line in FIG.

  FIG. 5 is an enlarged view of a main part of the power generation system shown in FIG.

  In FIG. 5, the power generation system 1 includes the heat source 2, the first device 3, and the second device 4 as described above.

  In this power generation system 1, the branch pipe 18 of the exhaust manifold 17 in the internal combustion engine 11 is used as the heat source 2, and the first device 3 is disposed around the branch pipe 18.

  The first device 3 is a composite element composed of an electrically polarizable matrix and a dispersed material having a specific heat capacity lower than the specific heat capacity of the matrix, and is formed by dispersing the dispersed material in the matrix. Is done.

  Such a composite element can be obtained as a mixture of, for example, a powder of a matrix material for forming a matrix and a powder of a dispersion material, and dispersing the dispersion material in the matrix material. .

Examples of the matrix material include known pyroelectric element materials (for example, BaTiO ₃ , CaTiO ₃ , (CaBi) TiO ₃ , BaNd ₂ Ti ₅ O ₁₄ , BaSm ₂ Ti ₄ O ₁₂ , lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ )), known thermoelectric conversion element materials (for example, Bi—Te based thermoelectric conversion elements (for example, Bi ₂ Te ₃ , Bi ₂ Te ₃ / Sb ₂ Te ₃ )), PbTe , AgSbTe ₂ / GeTe, NaCo ₂ O ₄ , CaCoO ₃ , SrTiO ₃ / SrTiO ₃ : Nb, SiGe, β-FeSi ₂ , Ba ₈ Si ₄₆ , Mg ₂ Si, MnSi _1.73 , ZnSb, Zn ₄ Sb ₃ , _{CeFe 3 CoSb 12, LaFe 3 CoSb} 12, SrTiO 3 / SrTiO 3: Nb / SrT O _3, Si nanowire _{arrays, NaCo 2 O 4, (Ce} 1-x La x) Ni 2, (Ce 1-x La x) In 3, etc. _{CeInCu 2, NaV 2 O 5,} V 2 O 5) , Known piezo element materials (for example, quartz (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), Rochelle salt (potassium sodium tartrate) (KNaC ₄ H ₄ O ₆ ), zircon titanate Lead acid (PZT: Pb (Zr, Ti) O ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), langasite (La ₃ Ga ₅₎ SiO ₁₄ ), aluminum nitride (AlN), tourmaline (tourmaline), polyvinylidene fluoride (PVDF) and the like.

  These matrix materials can be used alone or in combination of two or more.

  If a pyroelectric element material is used as the matrix material, a composite element that is electrically polarized by the pyroelectric effect (pyroelectric composite element) can be obtained. If a thermoelectric conversion element material is used, the matrix material is electrically polarized by the Seebeck effect. A composite element (thermoelectric conversion system composite element) is obtained, and if a piezo element material is used, a composite element (piezo system composite element) that is electrically polarized by the piezoelectric effect is obtained.

  The average particle diameter (measurement method: scanning electron microscope) of these matrix materials is, for example, 0.1 to 100 μm, preferably 0.5 to 10 μm.

  This is because, when the particle size of the matrix material is less than the above range, the crystal grain boundary fraction increases, so the temperature dependence of the dielectric constant increases, and the usable temperature range narrows. This is because when the particle size of the material exceeds the above range, the strength of the material is lowered because the fracture source size of the matrix material is increased.

  The specific heat capacity of the matrix material and the matrix formed from the matrix material is, for example, 0.01 to 10 J / g · K, and preferably 0.1 to 5 J / g · K.

  This is because if the specific heat capacity of the matrix material and the matrix formed from the matrix material is too low, the temperature of the entire material immediately rises due to the heat from the heat source, and the heat at the interface between the material and the electrode, etc. There is a possibility that the stress is remarkably increased and the electrode may be peeled. On the other hand, if the heat capacity is too high, the temperature change inside the material becomes dull with respect to the heat change from the outside. This is because it becomes difficult to generate electricity using the power.

  The dispersion material is not particularly limited as long as it has a specific heat capacity lower than that of the matrix material and the matrix formed from the matrix material. For example, Ru (ruthenium), Rh (rhodium), Pd (Palladium), Ag (silver), Os (osmium), Ir (iridium), noble metals such as Pt (platinum), such as Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Examples include transition metal simple substances such as Ni (nickel), Cu (copper), and Zn (zinc), and oxides, carbonates, nitrates, sulfates, diketone metal complexes, and hydride complexes thereof.

  These dispersion materials can be used alone or in combination of two or more.

  As a dispersion material, Preferably, the dispersion material which exists in a reduced state in 200-1000 degreeC, More preferably, in 200-500 degreeC is mentioned. Specific examples of such a dispersion material include Rh (rhodium), Pd (palladium), Ag (silver), Pt (platinum), Cr (chromium), Ni (nickel), and Cu (copper). Examples thereof include oxides, carbonates, nitrates, sulfates, diketone metal complexes, and hydride complexes.

  When such a dispersed material is used, since these dispersed materials are decomposed by reduction during the sintering of the matrix (described later), a fine dispersed phase can be formed.

  The average particle diameter (measurement method: scanning electron microscope) of these dispersed materials is, for example, 0.002 to 10 nm, preferably 0.01 to 3 nm.

  If the dispersed phase becomes too small, it will inhibit the sintering of the matrix (described later). If the dispersed phase becomes too large, it becomes easy to separate from the matrix, and the electrical conductivity, thermal conductivity, This is because the effect of mechanical properties is reduced.

  Further, the specific heat capacity of the dispersion material is lower than the specific heat capacity of the matrix material and the matrix formed from the matrix material from the viewpoint of changing the temperature in the composite element in conjunction with a heat source given from the outside. Specifically, for example, it is 0.01 to 10 J / g · K, preferably 0.1 to 5 J / g · K.

  The mixing ratio of the matrix material and the dispersion material is, for example, 0.01 to 50 parts by mass, preferably 0.1 to 40 parts by mass with respect to 100 parts by mass of the matrix material.

  In this method, the matrix material and the dispersion material are mixed by a known mixing method such as dry mixing or wet mixing, and, if necessary, formed by using a mold or the like (for example, press molding). A composite element in which a dispersion material is dispersed in a matrix can be obtained.

  In this method, the composite element can be sintered as necessary.

  As the sintering conditions, for example, in an inert gas atmosphere, the heating temperature is, for example, 500 to 1800 ° C., preferably 800 to 1500 ° C., and the heating time is, for example, 0.1 to 24 hours, preferably Is 0.5 to 4 hours. These conditions are appropriately optimized depending on the volume and shape of the sample so that the density of the composite element is most improved.

  And if such a 1st device 3 and the 1st device 3 which consists of a dispersive material which has a specific heat capacity lower than the specific heat capacity of a matrix in detail and an electrically polarizable matrix are used as the 1st device 3 simply, Compared with the case of using an electrically polarizable device, it is possible to generate electric power with superior efficiency.

  When the first device 3 is a pyroelectric composite element and / or a piezo composite element (insulator (dielectric)), the relative dielectric constant is, for example, 1 or more, preferably 100 or more. More preferably, it is 2000 or more.

  In such a power generation system 1, the higher the relative dielectric constant of the first device 3 (insulator (dielectric)), the higher the energy conversion efficiency and the higher voltage can be taken out. If the relative dielectric constant is less than the above lower limit, the energy conversion efficiency is low, and the voltage of the obtained power may be low.

  The first device 3 (insulator (dielectric)) is electrically polarized by the temperature change of the heat source 2, and the electrical polarization may be any of electronic polarization, ionic polarization, and orientation polarization.

  For example, it is expected that a material that exhibits polarization by orientation polarization (for example, a liquid crystal material) can improve power generation efficiency by changing its molecular structure.

  When the first device 3 is a thermoelectric conversion composite element, the performance is represented by, for example, the following formula (1).

ZT = S ² σT / κ (1)
(In the formula, Z represents a figure of merit, T represents an absolute temperature, S represents a Seebeck coefficient, σ represents electrical conductivity, and κ represents thermal conductivity.)
In such a first device 3 (thermoelectric conversion composite element), the ZT value (dimensionless figure of merit) is, for example, 0.3 or more.

  When the ZT value (dimensionless figure of merit) is less than the above lower limit, the energy conversion efficiency is low, and the voltage of the obtained power may be low.

  In general, since the thermoelectric conversion composite element generates power with a temperature difference inside the material, the lower the thermal conductivity, the higher the energy conversion efficiency. In this power generation system 1, the first device 3 (thermoelectric conversion system) There is no need for a temperature difference between both ends of the composite element). Therefore, the thermal conductivity of the first device 3 (thermoelectric conversion composite element) is not particularly limited.

  The second device 4 includes two electrodes arranged opposite to each other with the first device 3 interposed therebetween, and a conductive wire connected to the electrodes. In addition, the electrode and conducting wire which are arrange | positioned at one side of the 1st device 3 are arrange | positioned so that it may interpose between the 1st device 3 and the branch pipe 18 (heat source 2), and the other side of the 1st device 3 The electrodes and the conductors arranged in (1) are exposed without contacting the branch pipe 18 (heat source 2).

  Further, as shown in FIG. 4, the power generation system 1 is sequentially electrically connected to the booster 5, the AC / DC converter 6, and the battery 7.

  In such an automobile 10, the piston 16 is repeatedly moved up and down in each cylinder by driving the engine 16, and an intake process, a compression process, an explosion process, and an exhaust process are sequentially performed.

  More specifically, for example, in two cylinders, that is, a cylinder connected to the branch pipe 18a and a cylinder connected to the branch pipe 18c, the pistons are interlocked to perform the intake process, the compression process, the explosion process, and the exhaust process. , Implemented in phase. As a result, the fuel is combusted and power is output, and high-temperature exhaust gas passes through the branch pipe 18a and the branch pipe 18c in the exhaust process.

  At this time, the temperature of the branch pipe 18a and the branch pipe 18c rises in the exhaust process and falls in other processes (intake process, compression process, explosion process), so that it rises and falls over time according to the piston cycle, The high temperature state and the low temperature state are periodically repeated.

  On the other hand, in the two cylinders, the cylinder connected to the branch pipe 18b and the cylinder connected to the branch pipe 18d at different timings from the two cylinders, the pistons are interlocked, and the intake process, the compression process, The explosion process and the exhaust process are performed in the same phase. As a result, fuel is combusted and power is output, and at a timing different from that of the branch pipe 18a and the branch pipe 18c, high-temperature exhaust gas passes through the branch pipe 18b and the branch pipe 18d in the exhaust process.

  At this time, the temperature of the branch pipe 18b and the branch pipe 18d rises in the exhaust process and falls in other processes (intake process, compression process, explosion process), so that it rises and falls over time according to the piston cycle, The high temperature state and the low temperature state are periodically repeated.

  This periodic temperature change has the same period but a different phase from the periodic temperature changes of the branch pipe 18a and the branch pipe 18c.

  And in this electric power generation system 1, the 1st device 3 is arrange | positioned at each branch pipe 18 (heat source 2).

  Therefore, the first device 3 can be periodically brought into a high temperature state or a low temperature state due to a change in temperature of each branch pipe 18 (heat source 2) with time, and the first device 3 is turned into its element (for example, piezo). Can be electrically polarized by an effect (for example, a piezo effect, a pyroelectric effect, a Seebeck effect, or the like) according to a system composite element, pyroelectric system composite element, thermoelectric conversion system composite element, or the like.

  Therefore, in this power generation system 1, power can be extracted from each first device 3 through the second device 4 as a waveform (for example, alternating current, pulsating current) that periodically varies.

  Further, in this power generation system 1, since the temperature of the branch pipe 18a and the branch pipe 18c and the temperature of the branch pipe 18b and the branch pipe 18d change periodically with the same period and different phases, Can be continuously extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates automatically.

  Then, after passing through each branch pipe 18, the exhaust gas is supplied to the air collection pipe 19, collected, then supplied to the catalyst mounting section 12, and purified by the catalyst provided in the catalyst mounting section 12. Thereafter, the exhaust gas is supplied to the exhaust pipe 13, silenced in the muffler 14, and then discharged to the outside air through the discharge pipe 15.

  At this time, since the exhaust gas passing through each branch pipe 18 is collected in the air collection pipes 19, the exhaust gas sequentially passes through the air collection pipe 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14, and the exhaust pipe 15. The temperature is smoothed.

  Therefore, the temperature of the air collection pipe 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14 and the exhaust pipe 15 through which such exhaust gas whose temperature has been smoothed normally does not increase or decrease with time, It is constant.

  Therefore, when the air collecting pipe 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14 or the exhaust pipe 15 is used as the heat source 2 and the first device 3 is arranged around the second device 4 around the heat source 2. The electric power extracted from the first device 3 has a small voltage and is constant (DC voltage).

  Therefore, in such a method, there is a problem that the obtained electric power cannot be boosted efficiently with a simple configuration and the power storage efficiency is poor.

  On the other hand, as described above, in the power generation system 1 that employs the internal combustion engine 11 (branch pipe 18) as the heat source 2, the first device 3 is periodically changed to a high temperature state or a low temperature due to a temperature change of the heat source 2 with time. The first device 3 can be brought into a state, and an effect (for example, piezo effect, pyroelectric effect, etc.) according to the device (for example, piezo composite element, pyroelectric composite element, thermoelectric conversion composite element, etc.) The electric polarization can be periodically performed by the Seebeck effect or the like.

  Therefore, in this power generation system 1, power can be extracted from each first device 3 through the second device 4 as a waveform (for example, alternating current, pulsating current) that periodically varies.

  Thereafter, in this method, for example, as indicated by a dotted line in FIG. 4, the electric power obtained as described above is periodically changed in the booster 5 connected to the second device 4 (for example, alternating current, pulse, etc.). And then the boosted power is converted into a DC voltage by the AC / DC converter 6 and then stored in the battery 7. The electric power stored in the battery 7 can be used as appropriate as the power of the automobile 10 and various electrical components mounted on the automobile 10.

  And according to such a power generation system 1, since the heat source 2 whose temperature rises and falls with time is used, a fluctuating voltage (for example, AC voltage) can be taken out, and as a result, as a constant voltage (DC voltage) Compared with the case of taking out and converting by a DC-DC converter, it is possible to store the electric power by boosting with excellent efficiency.

  In particular, according to such a power generation system 1, since the first device 3 made of an electrically polarizable matrix and a dispersed material having a specific heat capacity lower than the specific heat capacity of the matrix is used, the electric power is simply used as the first device 3. Compared with the case where a polarizable device is used, it is possible to generate power with superior efficiency.

  Although not shown in detail, the first device 3 can be used in a stacked arrangement as shown in FIG. 2 according to the type of element, necessity and application, and further, as shown in FIG. Thus, it can also be arranged and arranged on the same plane.

  If the first device 3 is used in a stacked arrangement and / or arranged in the same plane, a plurality of first devices 3 can be simultaneously electrically polarized and electrically connected in series. Compared with the case where the 1st device 3 is used independently, big electric power can be taken out.

  In the above description, the first device 3 is arranged around the branch pipe 18 (outer wall). However, in order to transmit the temperature change to the first device 3 without averaging, the inside of the branch pipe 18 ( For example, it is preferable to arrange the first device 3 on the inner wall).

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the following examples.

Example 1
50 g of powder of aluminum oxide (Al ₂ O ₃ , average particle diameter (measured with a scanning electron microscope) 0.5 μm) and 12 g of powder of platinum oxide (PtO ₂ , average particle diameter (measured with a scanning electron microscope) 2 nm) Were weighed and mixed using a ball mill.

  Next, the obtained mixed powder was put into a 25 mm × 25 mm × 1.2 mm mold, pressure-molded at 30 MPa, and then sintered at 1400 ° C. for 2 hours to obtain a composite element.

  Next, a silver paste was applied on the front and back surfaces of the obtained composite element so as to have a size of 20 mm × 20 mm × 0.1 mm, thereby forming a silver electrode.

  Next, the obtained composite element and silver electrode were heat-treated at 400 ° C. for 2 hours in an atmospheric sintering furnace to obtain a sample.

  Then, while using 20 mm x 20 mm aluminum tape, one side of two conducting wires (lead wires) was stuck on each silver electrode, and the other side was connected to a digital multimeter.

  A heat gun was used as a heat source, the spray port was directed to the composite element, and the heat gun and the composite element were arranged so that the spray port was separated from the composite element by 5 cm.

  By blowing hot air from the heat gun and switching the heat gun on and off over time, the temperature of the heat gun and hot air is raised and lowered over time, and this temperature change raises and lowers the temperature of the composite element over time and electrically polarizes it. The generated voltage (electric power) was taken out through the electrode and the conductive wire.

  The temperature of the composite element was measured with an infrared radiation thermometer, and the hot air temperature was adjusted so that the temperature was 270 ° C. to 380 ° C.

  And the voltage change of the electric power taken out from the composite element was observed with the voltmeter. The relationship between the generated voltage and the temperature change is shown in FIG.

Example 2
40 g of powder of aluminum oxide (Al ₂ O ₃ , average particle diameter (measured by scanning electron microscope) 0.5 μm), and copper oxide (CuO, average particle diameter (measured by scanning electron microscope) 1.5 nm) Except for mixing 7.8 g of the powder, the temperature of the composite element was raised and lowered over time and electrically polarized in the same manner as in Example 1, and the generated voltage (electric power) was taken out through the electrode and the conductive wire. .

  And the voltage change of the electric power taken out from the composite element was observed with the voltmeter. The relationship between the generated voltage and the temperature change is shown in FIG.

Comparative Example 1
Except that the platinum oxide powder was not mixed, the temperature of the device was increased and decreased over time and the electric polarization was performed in the same manner as in Example 1, and the generated voltage (electric power) was taken out through the electrode and the conductive wire.

And the voltage change of the electric power taken out from the element was observed with the voltmeter. The relationship between the generated voltage and the temperature change is shown in FIG.
(Discussion)
The displacement (ΔV) of the generated voltage by the composite element of Example 1 is about 1.3 V (see FIG. 6), and the displacement (ΔV) of the generated voltage by the composite element of Example 2 is about 2.0 V. (See FIG. 7).

  On the other hand, the displacement (ΔV) of the generated voltage by the element of Comparative Example 1 is about 1.0 V, which is lower than the displacement (ΔV) in each example (see FIG. 8).

  As a result, the use of a composite element made of an electrically polarizable matrix and a dispersion material having a specific heat capacity lower than the specific heat capacity of the matrix produces electric power with superior efficiency compared to the case of using only an electrically polarizable element. It was confirmed that it was possible.

DESCRIPTION OF SYMBOLS 1 Power generation system 2 Heat source 3 1st device 4 2nd device 5 Booster 6 AC / DC converter 7 Battery

Claims (2)

A heat source whose temperature rises and falls over time;
An electrically polarizable matrix, and a first device made of a dispersion material having a specific heat capacity lower than the specific heat capacity of the matrix and electrically polarized by a temperature change of the heat source;
A second device for extracting power from the first device ;
The heat source is an exhaust gas pipe of an internal combustion engine in which an intake process, a compression process, an explosion process, and an exhaust process are sequentially performed, the temperature rises in the exhaust process, and the temperature decreases in the intake process, the compression process, and the explosion process. > A power generation system characterized by that. The power generation system according to claim 1, wherein the dispersion material is in a reduced state at 200 to 500C.

Images