Peltier element

Abstract

A conventional thermoelectric cooling device using a Peltier element provides a Peltier element with excellent cooling efficiency. [Solution] The Peltier element 1 is a thermal battery consisting of a first electrode 2 and a second electrode 3 facing each other with an electrolyte 4 interposed therebetween, and the Peltier element effect is obtained by passing positive and negative current through the thermal battery. The electrolyte is an electrolytic solution containing an alkali metal salt or alkaline earth metal salt and a solvent.

Description

[Technical Field]

[0001] The present invention relates to a Peltier element. [Background technology]

[0002] Conventionally, cooling devices that use fluorocarbons as a refrigerant have been used to cool heat-generating equipment and indoor spaces. In recent years, due to regulations such as the Fluorocarbons Emission Control Law, there has been a demand for cooling devices that do not use fluorocarbons as a refrigerant.

[0003] As a cooling device that does not use chlorofluorocarbon as a refrigerant, for example, a thermoelectric cooling device that uses a Peltier element is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-194926 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional thermoelectric cooling devices using Peltier elements have a problem in that they have low cooling efficiency and are difficult to put into practical use.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a Peltier element having excellent cooling efficiency in a conventional thermoelectric cooling device using a Peltier element. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A thermal battery comprising a first electrode and a second electrode facing each other with an electrolyte interposed therebetween; A Peltier element in which a Peltier element effect is obtained by passing positive and negative currents through the thermal battery. [2] The Peltier element according to [1], wherein the electrolyte is an electrolytic solution containing an alkali metal salt or an alkaline earth metal salt and a solvent. [Effects of the Invention]

[0008] According to the present invention, a thermoelectric cooling device using a conventional Peltier element can provide a Peltier element with excellent cooling efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a Peltier element made of a thermal battery according to one embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram showing a first example of an application of a Peltier element in one embodiment of the present invention. [Figure 3] FIG. 10 is a block diagram showing a second example of an application of a Peltier element in one embodiment of the present invention. [Figure 4] FIG. 10 is a block diagram showing a third example of an application of a Peltier element in one embodiment of the present invention. [Figure 5] FIG. 10 is a block diagram showing a fourth example of an application of a Peltier element in one embodiment of the present invention. [Figure 6] FIG. 10 is a block diagram showing a fifth example of an application of a Peltier element in one embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing the results of evaluating temperature changes in Example 1, in which a current of I=±1 mA is applied to a thermal battery in a thermostatic chamber at 25° C., and the direction of the current is switched every 20 seconds. [Figure 8] FIG. 10 is a diagram showing the results of evaluating temperature changes in Example 2 when a current of I=±1 mA is applied to a thermal battery in a thermostatic chamber at 25° C. and the direction of the current is switched every 20 seconds. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the Peltier element of the present invention will be described. It should be noted that the present embodiment is specifically described to allow a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[0011] [Peltier element] The Peltier element of this embodiment will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the Peltier element of this embodiment. The Peltier element 1 of this embodiment is a thermal battery. As shown in Fig. 1, the Peltier element 1 of this embodiment includes a unit 5 having a first electrode 2, a second electrode 3, and an electrolyte 4. In the Peltier element 1, the first electrode 2 is provided on one surface 6a of the collector electrode 6, and the second electrode 3 is provided on the other surface 6b of the collector electrode 6, with the first electrode 2 and the second electrode 3 arranged opposite each other with the collector electrode 6 interposed therebetween. The first electrode 2 and the second electrode 3 are arranged opposite each other with a separator 7 interposed therebetween. The first electrode 2 and the second electrode 3 are arranged opposite each other with a predetermined distance between them and a single electrolyte 4 impregnated in the separator 7. A plurality of units 5 each having the first electrode 2, the second electrode 3, and the electrolyte 4 are stacked such that the first electrode 2 of one unit 5 and the second electrode 3 of the other unit 5 are adjacent to each other with the collector electrode 6 interposed therebetween. The first electrode 2 and the second electrode 3 are electrically connected via a lead wire 8. A circuit (not shown) or a device (not shown) for extracting the current generated in the Peltier element (thermal battery) 1 may be provided along the lead wire 8. Furthermore, these components are sealed with a laminate film 9.

[0012] The first electrode 2 and the second electrode 3 include a material into which the same metal ions reversibly enter and exit. Alternatively, the first electrode 2 and the second electrode 3 may include a material into which the same metal ions precipitate or are alloyed.

[0013] The material contained in the first electrode 2 is Na x1 Co 1-y1 A z1 [Fe(CN)6] z1(However, A is at least one selected from the group consisting of Fe, Mn, Ni, and Zn, 0.8 < x1 < 2.0, 0.0 < y1 < 1.0, 0.7 < z1 < 1.0), and examples of the compound (cobalt Prussian blue analog (Co-PBA)) represented thereby include Na 1.60 Co 0.44 Mn 0.56 [Fe(CN)6] 0.90 and the like.

[0014] Examples of the material contained in the second electrode 3 include Na x2 M 1-y2 [Fe(CN)6] z2 (However, M is at least one selected from the group consisting of Ni, Mn, Cu, and Cd, 0.8 < x2 < 2.0, 0.0 < y2 < 1.0, 0.7 < z2 < 1.0), and examples of the compound represented thereby include Na 1.76 Ni[Fe(CN)6] 0.94 and the like.

[0015] In addition to the above electrode materials, the first electrode 2 and the second electrode 3 may contain a binder resin (binder) and a conductive aid. Examples of the binder resin include polyvinylidene fluoride (PVdF) resin, polytetrafluoroethylene (PTFE) resin, fluororubber, and the like. Examples of the conductive aid include Ketjen black, acetylene black (AB), furnace black, vapor-grown carbon fiber (VGCF), carbon nanotube, and the like.

[0016] The electrolyte 4 is not particularly limited as long as it is used in a thermal battery, but an electrolytic solution containing an alkali metal salt or an alkaline earth metal salt and a solvent is preferred.

[0017] Examples of the alkali metal salt include lithium salts, sodium salts, and the like. Examples of the alkaline earth metal salt include magnesium salts, and the like.

[0018] Examples of lithium salts include lithium nitrate (LiNO3), lithium chloride (LiCl), lithium perchlorate (LiCLO4), lithium sulfate (Li2SO4), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Examples of sodium salts include sodium nitrate (NaNO3), sodium chloride (NaCl), sodium sulfate (Na2SO4), sodium perchlorate (NaClO4), and sodium bis(trifluoromethanesulfonyl)imide (NaTFSI). Examples of magnesium salts include magnesium nitrate (Mg(NO3)2), magnesium chloride (Mg(Cl)2), magnesium sulfate (MgSO4), magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2), and the like.

[0019] Examples of the solvent include water, propylene carbonate (PC), ethylene carbonate (EC), and diethyl carbonate (DEC).

[0020] The concentration of the electrolyte in this embodiment is preferably 0.1 mol / L or more, and is preferably a concentration at which the electrolyte becomes a saturated solution. When the concentration of the electrolyte is equal to or more than the lower limit, the resistance of the electrolyte does not become too high, and there is no adverse effect when the electrolyte is used in a Peltier element.

[0021] The electrolyte solution in this embodiment can be obtained by dissolving the lithium salt, the sodium salt, or the magnesium salt in a solvent. The method for dissolving the lithium salt or the magnesium salt in the solvent is not particularly limited, and examples thereof include a method of stirring a mixture of the solvent and the lithium salt, the sodium salt, or the magnesium salt with a stirring blade or a magnetic stirrer.

[0022] 1 illustrates a case in which a plurality of units 5, each having a first electrode 2, a second electrode 3, and an electrolyte 4, are stacked in the Peltier element 1 such that the first electrode 2 of one unit 5 is adjacent to the second electrode 3 of the other unit 5, but this embodiment is not limited to this. The Peltier element 1 of this embodiment may be composed of a single unit 5 having the first electrode 2, the second electrode 3, and the electrolyte 4.

[0023] The Peltier element 1 of this embodiment achieves the Peltier element effect by passing positive and negative current through the Peltier element (thermal battery) 1. That is, by passing a negative current through the Peltier element 1, the temperature of the Peltier element 1 decreases, and by passing a positive current through the Peltier element 1, the temperature of the Peltier element 1 increases. In this way, by switching the current passed through the Peltier element 1 between a positive current and a negative current, the change in temperature of the Peltier element 1 can be reversed between positive and negative.

[0024] An application example of the Peltier element of this embodiment will be described.

[0025] (First example) Fig. 2 is a block diagram showing a first example of application of the Peltier element of this embodiment, in which the Peltier element of this embodiment is applied to an automobile air conditioning system. As shown in FIG. 2, the automobile air conditioning system of this example includes a battery 11, a blower 12, and a Peltier element 13.

[0026] The battery 11 is connected to the blower 12 and the Peltier element 13 via wiring. The battery 11 supplies current to the blower 12 to drive the blower 12, and also supplies current to the Peltier element 13 to control the temperature of the Peltier element 13.

[0027] In this example of an automobile air conditioning system, hot or cold air generated around the Peltier element 13 due to changes in temperature of the Peltier element 13 is sent by a blower 12 to the object to be heated or cooled (a drive device such as an engine, or the interior of the automobile).

[0028] In this example of an automotive air conditioning system, the Peltier element 13 can be used to downsize the air conditioning system. This allows for increased space inside the vehicle. Furthermore, the use of the Peltier element 13 can replace existing automotive gas refrigerants in light of PFAS regulations.

[0029] (Second example) 3 is a block diagram showing a second example of application of the Peltier element of this embodiment, in which the Peltier element of this embodiment is applied to a battery early warm-up system during cold start. As shown in FIG. 3, the battery early warm-up system of this example includes a battery 21, a vehicle drive device 22, and a Peltier element 23.

[0030] Battery 21 is connected via wiring to vehicle drive device 22 and Peltier element 23. Battery 21 supplies current to vehicle drive device 22 to drive vehicle drive device 22, and also supplies current to Peltier element 23 to control the temperature of Peltier element 23.

[0031] The vehicle drive device 22 has a motor MG, a power transmission mechanism GT (a reduction gear and a differential gear mechanism), and a power supply module PWR (an inverter INV, a converter, and a charging circuit).

[0032] In this example of the battery early warm-up system, the heat generated in the Peltier element 23 is transferred to the battery 21 by changing the temperature of the Peltier element 23, thereby promoting chemical reactions within the battery 21 during cold starting and improving the performance of the battery 21.

[0033] (Third example) Fig. 4 is a block diagram showing a third example of application of the Peltier element of this embodiment, in which the Peltier element of this embodiment is applied to a battery early warm-up system during cold start. As shown in FIG. 4, the early battery warm-up system of this example includes a battery 31, a vehicle drive device 32, a Peltier element 33, and an external power supply .

[0034] The battery 31 is connected to the vehicle drive device 32 via wiring. The battery 31 supplies current to the vehicle drive device 32 to drive the vehicle drive device 32.

[0035] The external power supply 34 is connected via a wire to the Peltier element 33. The external power supply 34 controls the temperature of the Peltier element 33 by supplying a current to the Peltier element 33.

[0036] In this example of the battery early warm-up system, the heat generated in the Peltier element 33 is transferred to the battery 31 by changing the temperature of the Peltier element 33, thereby promoting chemical reactions within the battery 31 during cold starting and improving the performance of the battery 31.

[0037] (Example 4) Fig. 5 is a block diagram showing a fourth example of application of the Peltier element of this embodiment, in which the Peltier element of this embodiment is applied to a cooling system for charging a battery. 5, the cooling system of this example includes an external power supply 41, a battery 42, and a Peltier element 43. The battery 42 and the Peltier element 43 are mounted on the automobile.

[0038] The external power supply 41 is connected via wiring to the battery 42 and the Peltier element 43. The external power supply 41 charges the battery 42 and also controls the temperature of the Peltier element 43 by passing a current through the Peltier element 43.

[0039] In this example of the cooling system, the cool air generated in the Peltier element 43 due to changes in the temperature of the Peltier element 43 is transferred to the battery 42, thereby suppressing heat generation in the battery 42 when the battery 42 is being charged and preventing deterioration or damage to the battery 42.

[0040] (Fifth Example) Fig. 6 is a block diagram showing a fifth example of application of the Peltier element of this embodiment, in which the Peltier element of this embodiment is applied to a cooling system for a vehicle drive device. As shown in FIG. 6, the cooling system of this example includes a battery 51, a vehicle drive device 52, and a Peltier element 53.

[0041] Battery 51 is connected via wiring to vehicle drive device 52 and Peltier element 53. Battery 51 drives vehicle drive device 52 and also supplies current to Peltier element 53 to control the temperature of Peltier element 53.

[0042] In the cooling system of this example, the heat generated by the vehicle drive device 52 is reduced by the Peltier element 53, thereby suppressing heat generation by the vehicle drive device 52 and improving the performance of the vehicle drive device 52. [Example]

[0043] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0044] [Example 1] (Preparation of Co-PBA electrode) A cobalt Prussian blue analogue was precipitated by mixing aqueous solutions containing 10 mmol / L of Na4[Fe(CN)6], 10 mmol / L of CoCl2, and 4 mol / L of NaCl. The precipitate was filtered, washed thoroughly with distilled water, and dried to obtain a powder. The composition of the obtained cobalt Prussian blue analogue (Co-PBA) was analyzed by energy dispersive X-ray spectroscopy (SEM-EDXS). 1.48 Co[Fe(CN)6] 0.87 The SEM-EDXS device used was a scanning electron microscope JSM-IT200 manufactured by JEOL Ltd. The Co-PBA powder obtained as described above, acetylene black, and polyvinylidene fluoride (PVdF) resin were mixed in a ratio of 7:2:1, and dispersed in N,N-dimethylformamide solvent to form a slurry. The slurry was applied to an indium tin oxide (ITO) electrode and dried overnight at 65°C in vacuum to obtain a Co-PBA electrode.

[0045] (Preparation of Ni-PBA electrodes) A nickel Prussian blue analogue was precipitated by mixing aqueous solutions containing 10 mmol / L of Na4[Fe(CN)6], 10 mmol / L of NiCl, and 4 mol / L of NaCl. The precipitate was filtered, washed thoroughly with distilled water, and dried to obtain a powder. The composition of the obtained nickel Prussian blue analogue (Ni-PBA) was analyzed by energy dispersive X-ray spectroscopy (SEM-EDXS). 1.76 Ni[Fe(CN)6] 0.94 The SEM-EDXS device used was a scanning electron microscope JSM-IT200 manufactured by JEOL Ltd. The Ni-PBA powder obtained as described above, acetylene black, and polyvinylidene fluoride (PVdF) resin were mixed in a ratio of 7:2:1, and the mixture was dispersed in N,N-dimethylformamide solvent to form a slurry. The slurry was then applied to an indium tin oxide (ITO) electrode and dried overnight in vacuum at 65°C to obtain a Ni-PBA electrode.

[0046] (Adjusting the electrodes) The Co-PBA electrode obtained above was initially oxidized to 0.55 V by passing a constant current through a charge-discharge device (model: HJ1001SD8, manufactured by Meiden Hokuto Co., Ltd.) in a three-electrode cell using platinum as the counter electrode, an Ag / AgCl standard electrode as the reference electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as the electrolyte, to obtain a positive electrode. In addition, the Ni-PBA electrode obtained above was initially oxidized to 0.55 V by passing a constant current through a three-electrode cell using platinum as the counter electrode, an Ag / AgCl standard electrode as the reference electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as the electrolyte using a charge-discharge device (model: HJ1001SD8, manufactured by Meiden Hokuto Co., Ltd.), to obtain a negative electrode. A thermal battery was fabricated using a positive electrode, a negative electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as an electrolyte.

[0047] (evaluation) An applied current of I = ±1 mA was applied to the thermal battery in a constant temperature bath at 25°C, and the direction of the current was switched every 20 seconds to evaluate the temperature change (-I → open state → +I → open state, etc.). The results are shown in Figure 7. From the results shown in Figure 7, it was confirmed that by passing positive and negative currents through the thermal battery, the temperature change of the thermal battery reversed from positive to negative.

[0048] [Example 2] (Preparation of Co-PBA electrode) A Co-PBA electrode was prepared in the same manner as in Example 1.

[0049] (Preparation of Mn-PBA electrode) A manganese Prussian blue analogue was precipitated by mixing aqueous solutions containing 40 mmol / L of Na4[Fe(CN)6], 40 mmol / L of MnCl2, and 4 mol / L of NaCl. The precipitate was filtered, washed thoroughly with distilled water, and dried to obtain a powder. The composition of the obtained manganese Prussian blue analogue (Mn-PBA) was analyzed by energy dispersive X-ray spectroscopy (SEM-EDXS). 1.56 Mn[Fe(CN)6] 0.89 The SEM-EDXS device used was a scanning electron microscope JSM-IT200 manufactured by JEOL Ltd. The Mn-PBA powder obtained as described above, acetylene black, and polyvinylidene fluoride (PVdF) resin were mixed in a ratio of 7:2:1, and dispersed in N,N-dimethylformamide solvent to form a slurry. The slurry was then applied to an indium tin oxide (ITO) electrode and dried overnight at 65°C in vacuum to obtain a Mn-PBA electrode.

[0050] (Adjusting the electrodes) The Co-PBA electrode obtained above was initially oxidized to 0.55 V by passing a constant current through a charge-discharge device (model: HJ1001SD8, manufactured by Meiden Hokuto Co., Ltd.) in a three-electrode cell using platinum as the counter electrode, an Ag / AgCl standard electrode as the reference electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as the electrolyte, to obtain a positive electrode. In addition, the Mn-PBA electrode obtained above was initially oxidized to 0.55 V by passing a constant current through a three-electrode cell using platinum as the counter electrode, an Ag / AgCl standard electrode as the reference electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as the electrolyte using a charge-discharge device (model: HJ1001SD8, manufactured by Meiden Hokuto Co., Ltd.), to obtain a negative electrode. A thermal battery was fabricated using a positive electrode, a negative electrode, and a 17 mol / kg aqueous solution of sodium perchlorate (NaClO4) as an electrolyte.

[0051] (evaluation) An applied current of I = ±1 mA was applied to the thermal battery in a constant temperature bath at 25°C, and the direction of the current was switched every 20 seconds to evaluate the temperature change (-I → open state → +I → open state, etc.). The results are shown in Figure 8. From the results shown in Figure 8, it was confirmed that by passing positive and negative currents through the thermal battery, the temperature change of the thermal battery reversed from positive to negative. [Industrial Applicability]

[0052] The Peltier element of the present invention can be used in automobile air conditioning systems, systems for quickly warming up a battery during cold start, cooling systems for charging a battery, cooling systems for a vehicle drive unit, and the like. [Explanation of symbols]

[0053] 1 Peltier element 2 First electrode 3 Second electrode 4 Polyelectrolyte 5 units 6 Collector electrode 7 Separator 8 Lead Wires 9. Laminating film

Claims

1. a thermal battery having a first electrode and a second electrode facing each other with an electrolyte interposed therebetween; A Peltier element in which a Peltier element effect is obtained by passing positive and negative currents through the thermal battery.

2. 2. The Peltier element according to claim 1, wherein the electrolyte is an electrolytic solution containing an alkali metal salt or an alkaline earth metal salt and a solvent.

Images