JP2009076603A - Manufacturing method of thermoelectric conversion module for power generation, and thermoelectric conversion module for power generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a manufacturing method of a thermoelectric conversion element having an inexpensive manufacturing cost and high manufacturing efficiency; and the thermoelectric conversion module having high output density per unit area. <P>SOLUTION: This thermoelectric conversion module for power generation is manufactured by a first process in which a grid-like honeycomb spacer formed of a material having a thickness of 0.2 mm-0.8 mm is put in the top opening part of a honeycomb molding die, and 0.5 mm-1.5 mm square rod-shaped P-type and N-type thermoelectric element are alternately inserted through each grid in the honeycomb molding die the top opening part of which is partitioned in a grid shape by the honeycomb spacer, a second process in which an insulating resin is impregnated and cured to mold it as a block in a gap mutually between the P-type and N-type thermoelectric elements installed in the honeycomb molding die with a fixed space existing between them, a third process in which the block is cut in the direction perpendicular to the longitudinal direction of each element for every prescribed thickness to make block pieces, and a fourth process in which after plating so that the P-type and N-type thermoelectric elements on both sides of the block piece are alternately and electrically connected in series, an electrode is soldered to the forefront and last elements in an element group connected in series. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a thermoelectric conversion module for power generation that directly converts a temperature difference into electricity, and a thermoelectric conversion module for power generation.

  Thermoelectric materials are applied in two ways: temperature control elements that use the Peltier effect and power generation elements that use the Seebeck effect.

  The former temperature control element using the Peltier effect is used for temperature control, and has become indispensable for cooling a laser oscillator with the spread of optical communication in addition to a portable temperature refrigerator.

  On the other hand, for the power generation element using the latter Seebeck effect, a power generation system of several W to several tens W class using industrial waste heat has been studied, but the thermoelectric conversion efficiency is low, the power generation cost is high, etc. Has not yet been put into practical use.

  In recent years, in a generator installed in a factory, various sensors are installed and remote monitoring / control is performed. These sensors are supplied with electricity from a battery or a 100 V power source. However, when the battery is used, it is naturally consumed with the passage of time, so that it is necessary to replace the battery at regular intervals.

  By the way, although the driving power of the sensor depends on the type, it is generally several tens to hundreds of tens of mW. On the other hand, heat is generated during operation of the generator, so the temperature difference between the heat generation temperature of the generator and the outside temperature If this is used, there is a possibility that a driving power source for the sensor can be obtained by the thermoelectric conversion module.

  FIG. 5 is a diagram schematically showing a thermoelectric power generation system using a conventional thermoelectric conversion module.

  As shown in FIG. 5, this thermoelectric power generation system is configured such that a heat conductive sheet 2 is provided on the upper surface of the thermoelectric conversion module 1 and a heat sink 3 is disposed on the upper surface, and the generated power obtained from the thermoelectric conversion module 1 is output to the output terminal 4. It is taken out and given to the DC / DC converter 5 to be converted into a desired voltage.

  However, in the configuration of the thermoelectric power generation system as shown in FIG. 5, since the amount of heat generated from the generator is small, the power necessary for driving the sensor can be obtained unless a large number of thermoelectric conversion modules are connected in series. In addition, the power generation cost is not only expensive, but also the desired amount of power generation per installation area cannot be obtained.

By the way, as a method of manufacturing a thermoelectric element that uses P-type and N-type thermoelectric semiconductor materials to enable temperature difference power generation by the Seebeck effect and electronic cooling / heating by the Peltier effect, a columnar shape is sandwiched between a pair of substrates. When the P-type thermoelectric material and the N-type thermoelectric material are electrically joined alternately, the thermoelectric material is installed in the concave portion of the electrode patterned on the substrate (Patent Document 1), or the P-type thermoelectric material When the substrate to which the P-type thermoelectric material is bonded and the substrate to which the N-type thermoelectric material are bonded face each other by cutting and deleting the N-type thermoelectric material, the first substrate and the second substrate and P Type thermoelectric material and N-type thermoelectric material are temporarily mounted using a bonding agent (Patent Document 2), both of which are themes when installing or mounting a substrate and a thermoelectric material Is, Not intended for position to increase the amount of power generation per area.
JP 2006-278352 A JP 2006-261152 A

  A commercially available thermoelectric conversion module is manufactured on the assumption that it is used as a Peltier element. Usually, a large number of elements obtained by cutting a bismuth-tellurium-based material of 1.5 mm to 2.0 mm square into a dice are 1 They are arranged in series at intervals of ˜1.5 mm.

  In order to manufacture such a thermoelectric conversion module, first, a bismuth-tellurium unidirectionally solidified bar made into a 20 to 40 mm rod shape is cut into a wafer shape with a thickness of about 1 to 2 mm using a wire saw or the like. Then, it is cut into a predetermined dice shape with a dicing saw.

  Then, the thermoelectric conversion module was manufactured by arranging the dice-like thermoelectric conversion materials so that P and N were alternately arranged in series and connected to the electrodes with solder. In this case, in terms of the accuracy of the dicing saw, the element size can be 1 mm or less.

  However, bismuth-tellurium-based thermoelectric conversion materials are brittle materials, and if they are 1 mm or less, the incidence of materials that cannot be used due to chipping increases, the accuracy of element positioning jigs becomes strict, and the cost of element assembly Problems such as rising.

  Furthermore, as a problem peculiar to the assembly process of the thermoelectric conversion module using a machine, there is a short circuit between elements due to excessive solder at the time of soldering. It is produced with the interval of.

  When the thermoelectric conversion module manufactured in this way is used as a power source for a sensor or the like, it is necessary to generate a minimum input voltage of a step-up electric circuit (DC / DC converter).

  Moreover, since the installation area of the thermoelectric conversion module is limited, a module with high output density is required. In this case, the electromotive voltage per unit area is determined by the number of element pairs of P-type elements and N-type elements per unit area, and the electromotive voltage increases as the number of element pairs increases.

  However, since the conventional thermoelectric conversion module has a large element size and a wide element interval, it has not been possible to obtain a sufficient electromotive voltage under desired use conditions.

  The present invention has been made in view of the above circumstances, and a method for producing a thermoelectric conversion module for power generation and a thermoelectric conversion module for power generation that have a high electromotive voltage per unit area, a low production cost, and a high production efficiency. The purpose is to provide.

  In order to achieve the above object, the present invention sandwiches a lattice-shaped honeycomb spacer made of a plate material having a thickness of 0.2 mm to 0.8 mm in the upper surface opening of the honeycomb mold, and the upper surface opening is formed by the honeycomb spacer. A first step of alternately inserting 0.5 mm to 1.5 mm square rod-shaped P-type thermoelectric elements and N-type thermoelectric elements through each grid into a honeycomb mold in which the portions are partitioned in a grid pattern; In a second step of forming a block by impregnating and curing an insulating resin in a gap between a P-type thermoelectric element and an N-type thermoelectric element installed at a certain interval in the mold, and in this second step A third step of cutting the formed block into a block piece by cutting at a predetermined thickness in a direction orthogonal to the longitudinal direction of each element, and both sides of the block piece cut in the third step P-type and N-type thermoelectric elements And the fourth step of soldering the electrode serving as the output terminal to the first and last elements of the series-connected elements after plating so that they are alternately electrically connected in series, and the thermoelectric conversion module for power generation Manufacturing.

  According to the present invention, a thermoelectric conversion module with low manufacturing cost and high manufacturing efficiency can be manufactured, and a thermoelectric conversion module with high output density per unit area can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a process diagram showing a first embodiment for explaining a method for producing a thermoelectric conversion module for power generation according to the present invention.

  In FIG. 1, the rod-shaped P-type element 6 and N-type element 7 are two-part molds that have a desired rod-like shape made of isotropic high-density graphite material (for example, ISO-88 manufactured by Toyo Tanso Co., Ltd.). It is prepared as a rod-shaped bismuth and tellurium material by pouring and solidifying bismuth and tellurium dissolved in a mold that combines these, solidifying, and then separating the mold into the original two-part mold. (Not shown). This rod-shaped bismuth and tellurium material can be easily obtained in a range of 0.5 mm to 1.5 mm square, or 0.8 mm to 1.1 mmφ and 100 mm or more.

  Next, a honeycomb spacer 9 assembled in a lattice shape with a plate material having a thickness of 0.2 mm to 0.8 mm, for example, 0.5 mm, is sandwiched in the opening on the upper surface of the honeycomb forming die 8 such as a rectangular insulating box. For example, the above-described 0.5 mm square rod-shaped P-type elements 6 and N-type elements 7 are alternately inserted through the respective lattices into the honeycomb forming die 8 in which the upper surface openings are partitioned in a lattice shape by 9. Are arranged at constant intervals (0.5 mm intervals) in the vertical and horizontal directions.

  An insulating resin accommodated in the container 10 is impregnated and cured in a gap existing between the P-type element 6 and the N-type element 7 installed in the honeycomb forming die 8 to form a block 11 in which the whole is integrated. .

  Next, this block 11 is cut by a cutter 12 at a predetermined thickness in a direction orthogonal to the longitudinal direction of each element to form block pieces, and P-type elements and N-type elements on both sides (cut planes) Are plated so that they are alternately electrically connected in series, and then an electrode (not shown) is soldered to the most advanced element and the last element serving as an entrance / exit for energization by a micro soldering technique to manufacture the thermoelectric conversion module 13.

  According to such a manufacturing method, the P-type element 6 and the N-type element 7 are arranged at an interval corresponding to the thickness of the honeycomb spacer 9 between the elements, in this case 0.5 mm. In this way, it is possible to efficiently manufacture a thermoelectric conversion module having a high mounting density of 40 / cm 2 or more per unit area without causing the above-described problem. In addition, the element spacing can be 0.5 mm or less even in mass-produced products.

  Incidentally, a commercially available thermoelectric conversion module usually has 1.5 mm to 2.0 mm square elements assembled at intervals of 1 mm to 1.5 mm because of the assembly process using a machine. The mounting density per area is lower than that of the present invention, and there is a limit to increasing the electromotive voltage per unit area.

Here, the measurement results of the voltage generated by the thermoelectric conversion module (invention module) manufactured by the method of the present invention and the voltage generated by the conventional thermoelectric conversion module (conventional module) are verified by Table 1 as follows.

In Table 1 above, typical use conditions are a low temperature side temperature of 25 ° C. and a heat input of 0.28 W / cm ² . The invention module has an installation area of 42 mm square (1764 mm ² ) and P / N pairs of 392 pairs, whereas the conventional module has an installation area of 40 mm square (1600 mm ² ) and P / N pairs of 127 pairs.

Element logarithm per unit area of the invention the module 44.8 present / cm ² to 15.8 present / cm ² conventional module, which is about 2.8 times. Further, since the thermoelectromotive voltage is almost proportional to the number of elements, the electromotive voltage of the inventive module is 1.61 V, which is more than three times that of the conventional product.

  By the way, the minimum starting voltage of the current DC / DC converter requires 0.9 V (for example, when a linear regulator IC LTC3025 or the like is used).

As is clear from Table 1 above, the DC / DC converter is activated in the conventional module under typical usage conditions (low temperature 25 ° C., heat input 0.28 W / cm ² , sensor installation area 40 to 42 mm square). It can be seen that sufficient voltage is not obtained to activate the DC / DC converter in the inventive module, although sufficient voltage cannot be obtained to achieve this.

  It is a schematic diagram which shows the state which installed the thermoelectric conversion module produced by this invention in FIG.

  2 to 4, the heat source side steel plate 14 to be installed is ground on the surface of the plate, and the flatness is adjusted to 0.02 mm or less.

  FIG. 2 shows an installation example (hereinafter referred to as installation example 1) in which the heat source side plate 14 uses a material such as ferrite or a martensitic steel plate that adsorbs a magnet. That is, as shown in FIG. 2, a heat conduction sheet 15 for improving heat conduction is attached to the heat source side steel plate 14, and the thermoelectric conversion module 13 manufactured by the process shown in FIG. A generator having a configuration in which a heat sink 3 is provided via a heat conductive sheet 2 is installed, and an opening portion of a holding jig 17 in which a magnet 16 is stretched around the lower surface of a frame made of a steel plate is attached to the heat sink 3 of the generator. In a state where the small generator is brought into close contact with the heat source side steel plate 14 by inserting the magnet 16 to the heat source side steel plate 14 so as to press the flange portion on the heat conductive sheet 2 side of the heat sink 3 from above. It is to be fixed.

  FIG. 3 shows an example (hereinafter referred to as installation example 2) in which the generator is installed on the heat source side steel plate 14 and fixed with bolts. That is, as shown in FIG. 3, a heat conduction sheet 15 for improving heat conduction is pasted on the heat source side steel sheet 14, and a heat sink 3 is provided on the upper surface of the thermoelectric conversion module 13 and the heat conduction sheet 2 thereon. The generator having the above-described configuration is installed, the opening of the holding jig 18 made of a frame-shaped steel plate is inserted into the heat sink portion of the generator, and the flange portion on the heat conductive sheet 2 side of the heat sink 3 is pressed from above. Thus, the generator is fixed in a state of being in close contact with the heat source side steel plate 14 by screwing bolts 20 into taps or screw holes 19 provided in advance in the holding jig 18 and the heat source side steel plate 14, respectively. is there.

  FIG. 4 shows an example in which the generator is installed on the heat source side steel plate 14 and fixed by vacuum degassing (hereinafter referred to as installation example 3). That is, as shown in FIG. 4, a heat conductive sheet 15 for improving heat conduction is attached to the heat source side steel plate 14, and a heat sink 3 is provided on the upper surface of the thermoelectric conversion module 13 via the heat conductive sheet 2. The heat generator 2 of the heat sink 3 is inserted through the opening of the holding jig 22 provided with the vacuum packing 21 around the lower surface of the frame made of a steel plate. The generator is fixed in a state of being in close contact with the heat source side steel plate 14 by pressing the flange portion provided on the side from above and evacuating the vacuum packing 21.

Table 2 shows that in installation examples 1 to 3, a thermoelectric conversion module with 392 P / N pairs, a module size of 42 mm square, and a module height of 3 mm was used, and the heat input was 0.28 W / at 25 ° C. It shows the generated voltage (average value) before and after the input of the DC / DC converter when cm ^{2 is} given.

Table 2 also shows the results (conventional example) of evaluating commercially available modules (40 mm square modules, 127 P / N pairs, 3 mm module height) under the same conditions.

  As can be seen from Table 2 above, in the conventional example, the electromotive voltage after the input of the DC / DC converter is 0V, whereas in the installation examples according to the present invention, it is confirmed that an output of 3.0V can be obtained.

Process drawing which shows 1st Embodiment for demonstrating the manufacturing method of the thermoelectric conversion module by this invention. The schematic diagram which shows the 1st example of the state which installed the thermoelectric conversion module produced by this invention in the heat source. The schematic diagram which shows the 2nd example of the state which installed the thermoelectric conversion module produced by this invention in the heat source. The schematic diagram which shows the 3rd example of the state which installed the thermoelectric conversion module produced by this invention in the heat source. The schematic diagram which shows the state which installed the conventional thermoelectric conversion module in the heat source.

Explanation of symbols

  2 ... heat conduction sheet, 3 ... heat sink, 5 ... DC / DC converter, 6 ... P-type element, 7 ... N-type element, 8 ... honeycomb forming mold, 9 ... honeycomb spacer, 10 ... container, 11 ... block, 12 ... Cutter, 13 ... Thermoelectric conversion module, 14 ... Heat source side steel plate, 15 ... Heat conduction sheet, 16 ... Magnet, 17, 18, 22 ... Holding jig, 19 ... Screw hole, 20 ... Bolt, 21 ... Vacuum packing

Claims (4)

A honeycomb-shaped honeycomb spacer assembled with a plate material having a thickness of 0.2 mm to 0.8 mm is sandwiched in the upper surface opening of the honeycomb mold, and the upper surface opening is partitioned into a lattice by the honeycomb spacer. A first step of alternately inserting rod-shaped P-type thermoelectric elements and N-type thermoelectric elements of 0.5 mm to 1.5 mm square through each grid;
A second step of forming a block by impregnating and curing an insulating resin in a gap between the P-type thermoelectric element and the N-type thermoelectric element installed in the honeycomb mold at a certain interval;
A third step in which the block formed in the second step is cut into a block piece by cutting at a predetermined thickness in a direction orthogonal to the longitudinal direction of each element;
After plating so that the P-type thermoelectric elements and N-type thermoelectric elements on both sides of the block piece cut in the third step are alternately electrically connected in series, the first of the elements connected in series And a fourth step of soldering an electrode serving as an output terminal to the final element. In the manufacturing method of the power generation module according to claim 1,
A method for producing a thermoelectric conversion module for power generation, wherein a material containing bismuth and tellurium is used as a material for a P-type thermoelectric element and an N-type thermoelectric element. In the manufacturing method of the thermoelectric conversion module for electric power generation of Claim 1 or Claim 2,
The method for producing a thermoelectric conversion module for power generation, wherein the number of thermoelectric conversion elements per unit area is 40 / cm ² or more.   A thermoelectric conversion module for power generation manufactured by the method according to any one of claims 1 to 3.

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