WO2017017757A1 - Thermoelectric conversion module and method for manufacturing same - Google Patents

Thermoelectric conversion module and method for manufacturing same Download PDF

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Publication number
WO2017017757A1
WO2017017757A1 PCT/JP2015/071226 JP2015071226W WO2017017757A1 WO 2017017757 A1 WO2017017757 A1 WO 2017017757A1 JP 2015071226 W JP2015071226 W JP 2015071226W WO 2017017757 A1 WO2017017757 A1 WO 2017017757A1
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thermoelectric conversion
conversion element
conversion module
element film
electrode
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PCT/JP2015/071226
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French (fr)
Japanese (ja)
Inventor
悦子 高根
藤原 伸一
知丈 東平
山口 欣秀
早川 純
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株式会社日立製作所
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Priority to PCT/JP2015/071226 priority Critical patent/WO2017017757A1/en
Publication of WO2017017757A1 publication Critical patent/WO2017017757A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02NELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N3/00Generators in which thermal or kinetic energy is converted into electrical energy by ionisation of a fluid and removal of the charge therefrom
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01Manufacture or treatment
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80Constructional details
    • H10N10/81Structural details of the junction
    • H10N10/817Structural details of the junction the junction being non-separable, e.g. being cemented, sintered or soldered

Definitions

  • the present invention relates to a thermoelectric conversion module and a manufacturing method thereof.
  • thermoelectric conversion member As a background art in this technical field, there is JP-A-2003-133600 (Patent Document 1).
  • Patent Document 1 describes a thermoelectric conversion member in which a P-type thermoelectric conversion element layer and an N-type thermoelectric conversion element layer are formed on the surface of a flexible substrate. The thermoelectric conversion member itself has flexibility. is doing.
  • thermoelectric conversion module having flexibility has been proposed by forming a thermoelectric conversion element film on a flexible substrate.
  • thermoelectric conversion module having desired reliability and thermoelectric performance also referred to as conversion performance or power generation performance
  • thermoelectric conversion module of the present invention directly joins the first joining surface of the P-type thermoelectric conversion element film with the high-temperature side electrode metal film formed on the high-temperature side substrate.
  • the second bonding surface opposite to the surface is bonded to the low-temperature electrode metal film through the bonding layer.
  • first bonding surface of the N-type thermoelectric conversion element film is directly bonded to the low temperature side electrode metal film formed on the low temperature side substrate, and the second bonding surface opposite to the first bonding surface is bonded to the bonding layer.
  • thermoelectric conversion module with improved reliability and thermoelectric performance can be provided. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
  • FIG. 3 is a main part cross-sectional view showing the manufacturing process of the thermoelectric conversion module following FIG. 2;
  • FIG. 4 is a main part cross-sectional view showing the manufacturing process of the thermoelectric conversion module following FIG. 3;
  • FIG. 5 is a main-portion cross-sectional view illustrating the manufacturing process of the thermoelectric conversion module following FIG. 4.
  • FIG. 6 is a cross-sectional view of the principal part showing the manufacturing process of the thermoelectric conversion module following FIG. 5.
  • thermoelectric conversion module It is a principal part side view which shows the element vicinity of the thermoelectric conversion module which the present inventors examined as a comparative example. It is a graph which shows the output power ratio of the thermoelectric conversion module by a present Example, and the thermoelectric conversion module by a comparative example. It is a principal part side view which shows the element vicinity of the thermoelectric conversion module by the modification 1. FIG. It is a principal part side view which shows the element vicinity of the thermoelectric conversion module by the modification 2.
  • the constituent elements are not necessarily indispensable unless otherwise specified and clearly considered essential in principle. Needless to say.
  • thermoelectric conversion element film refers to a thermoelectric element formed by an aerosol deposition method or the like.
  • thermoelectric conversion element film may be described as a thermoelectric element without particular notice.
  • Thermoelectric conversion modules are attracting attention as a method for recovering exhaust heat as thermal energy for the realization of an environmentally harmonious society. Watches and hot springs are used at low temperatures, incinerators, industrial furnaces, Expansion to related products such as automobiles is under consideration.
  • thermoelectric conversion module mainly adopts a so-called ⁇ -type structure in which P-type thermoelectric conversion elements and N-type thermoelectric conversion elements are arranged in series and alternately between a high temperature side substrate and a low temperature side substrate. For this reason, if the P-type thermoelectric conversion element and the N-type thermoelectric conversion element are rearranged even at one place during assembly, the thermoelectric conversion module may not operate because it does not flow. Therefore, it is an important issue to simplify the manufacturing process and establish a process without manufacturing errors. Furthermore, a melted material or a sintered material using a thermoelectric conversion material that is currently in practical use, such as a bismuth-tellurium-based material, has a problem of low strength and low workability.
  • thermoelectric conversion element layer on a flexible resin substrate by vapor deposition, the yield of element arrangement and element processing is improved, and the versatility of the installation form is improved.
  • a manufacturing method of a thermoelectric conversion module having a high flexible structure is described (see FIG. 5).
  • Patent Document 1 a plurality of P-type and N-type thermoelectric conversion element layers are formed by vapor deposition on the surface of either the high-temperature side or the low-temperature side flexible substrate.
  • N vapor deposition mask for forming a P-type thermoelectric conversion element film
  • N The alignment of the deposition mask for forming the type thermoelectric conversion element film must be strictly performed so that there is no pitch shift, and then the N type thermoelectric conversion element must be formed. This alignment requires a high level of technology, and is the most complicated step in the manufacturing process.
  • thermoelectric conversion module This warpage is expected to cause a crack in the thermoelectric conversion element layer, a decrease in the contact area with the heat source, and the like, and may reduce the reliability and thermoelectric performance of the thermoelectric conversion module.
  • An object of the present invention is to provide a technique for improving the reliability and thermoelectric performance of a thermoelectric conversion module.
  • FIG. 1 is a side view of an essential part showing the vicinity of an element of a thermoelectric conversion module according to the present embodiment.
  • reference numeral 1 is a thermoelectric conversion module element assembly
  • reference numeral 51 is a P-type thermoelectric conversion element film
  • reference numeral 52 is an N-type thermoelectric conversion element film
  • reference numeral 21 is a high-temperature side substrate
  • reference numeral 22 is a low-temperature side substrate
  • reference numeral 23 is
  • Reference numeral 24 denotes a high temperature side electrode metal film
  • reference numeral 24 denotes a low temperature side electrode metal film
  • reference numeral 32 denotes a bonding layer.
  • the first bonding surface of the P-type thermoelectric conversion element film 51 is directly bonded to the high temperature side electrode metal film 23 formed on the high temperature side substrate 21, and the first bonding surface on the opposite side to the first bonding surface.
  • the two bonding surfaces are bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22 via the bonding layer 32.
  • first bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22, and the second bonding surface opposite to the first bonding surface is The high temperature side electrode metal film 23 formed on the high temperature side substrate 21 is bonded via the bonding layer 32.
  • the P-type thermoelectric conversion element film 51 is directly formed on the high-temperature side electrode metal film 23 using any one of a vapor deposition method, a sputtering method, an aerosol deposition method, and a printing method.
  • the film 52 is directly formed on the low-temperature electrode metal film 24 using any one of a vapor deposition method, a sputtering method, an aerosol deposition method, and a printing method.
  • the high temperature side electrode metal film 23 and the low temperature side electrode metal film 24 may be patterned on the high temperature side substrate 21 and the low temperature side substrate 22, respectively, and the formation method thereof is not limited.
  • the high temperature side electrode metal film 23 and the low temperature side electrode metal film 24 are preferably composed of 90% by mass or more of copper, which has high electrical conductivity and thermal conductivity and is suitable as an electrode member.
  • the film thickness is preferably 0.5 mm or less.
  • the film thickness is preferably 1.0 ⁇ m or more.
  • the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 have a high power generation performance within the above temperature range in the case of a thermoelectric conversion module assumed to be used in the range of about 300 ° C. to 1,000 ° C.
  • a thermoelectric conversion element film made of any combination of germanium, magnesium-silicon, manganese-silicon, lead-tellurium, skutterudite, and half-Heusler alloy is preferred.
  • a Heusler alloy system and a bismuth-tellurium system are preferable from the viewpoint of power generation performance.
  • the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 have high oxidation resistance up to about 600 ° C., and the Heusler structure is stable up to about 1,150 ° C. Mention may be made of iron-vanadium-aluminum of certain Heusler alloys.
  • the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are mainly formed by using an aerosol deposition method.
  • the aerosol deposition method is a method of forming a thermoelectric conversion element film by colliding nanosized thermoelectric conversion material particles into a base material.
  • a force for expanding the collision caused by the particle collision and a restraining force from the inside of the base material without the influence of the particle collision work simultaneously.
  • thermoelectric conversion element film a compressive stress remains inside the thermoelectric conversion element film, and a tensile stress remains on the base material so as to balance the stress.
  • the film thickness is preferably in the range of 10 ⁇ m to 1,000 ⁇ m. If the thickness is less than 10 ⁇ m, it is difficult to control the thickness of the solder for connecting the thermoelectric element and the electrode, and there is a risk that the solder will elute and short-circuit at the time of joining. If it is thicker than 1,000 ⁇ m, the thermoelectric conversion element film may break.
  • the bonding layer 32 is made of a metal such as aluminum, indium, zinc, tin, gold or germanium, or solder.
  • the bonding layer 32 may be formed by any method such as vapor deposition, sputtering, aerosol deposition, thermal spraying, or ion plating. However, if the bonding layer 32 is too thin, there is a concern about a decrease in bonding strength and a decrease in thermoelectric performance due to the occurrence of unbonded portions.
  • the bonding layer 32 is too thick, the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 may be cracked due to the stress of the bonding layer 32.
  • the thickness of the bonding layer 32 is preferably in the range of 5.0 ⁇ m to 20.0 ⁇ m.
  • the bonding layer 32 has good bonding properties with thermoelectric elements when lead-free solder containing tin is used.
  • an electrode material when nickel is formed on the surface of copper and connected with the solder, a stable and highly reliable bonding layer interface can be formed.
  • the high temperature side substrate 21 and the low temperature side substrate 22 are insulating materials made of a resin such as polyimide, polyethylene terephthalate, polysulfone, polyether ketone, polyethylene or polyphenylene sulfite, or ceramics such as alumina, silicon nitride, or aluminum nitride.
  • a resin such as polyimide, polyethylene terephthalate, polysulfone, polyether ketone, polyethylene or polyphenylene sulfite, or ceramics such as alumina, silicon nitride, or aluminum nitride.
  • the resin can be produced in a sheet form. It is suitable for the present invention because it can be manufactured as a large-sized sheet-like member by the aerosol deposition method or the like, cut out to a necessary size, and used as appropriate.
  • the high temperature side substrate 21 and the low temperature side substrate 22 are preferably made of the same material. This is because, when the difference between the thermal expansion coefficient of the high temperature side substrate 21 and the thermal expansion coefficient of the low temperature side substrate 22 is smaller, the stress generated in the entire joint portion and the thermoelectric conversion module is reduced, so that the warpage of the thermoelectric conversion module is suppressed. This is because it can.
  • the high temperature side substrate 21 and the low temperature side substrate 22 can be polyimide resin, and the film thickness thereof can be 75 ⁇ m.
  • the first bonding surface of the P-type thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23 formed on the high-temperature side substrate 21, and the first bonding surface of the P-type thermoelectric conversion element 51 is The second bonding surface on the opposite side is bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22 via the bonding layer 32.
  • the first bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24 formed on the low-temperature side substrate 22, and is opposite to the first bonding surface of the N-type thermoelectric conversion element 52.
  • the second bonding surface is bonded to the high temperature side electrode metal film 23 formed on the high temperature side substrate 21 via the bonding layer 32.
  • thermoelectric conversion module the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are joined on one high-temperature side electrode metal film 23.
  • the N type thermoelectric conversion element film 52 is bonded to the high temperature side electrode metal film 23 through the bonding layer 32.
  • thermoelectric conversion module a P-type thermoelectric conversion element film 51 and an N-type thermoelectric conversion element film 52 are bonded on one low-temperature side electrode metal film 24, but the N-type thermoelectric conversion element film 52 is on the low temperature side.
  • the P-type thermoelectric conversion element film 51 is bonded to the low-temperature-side electrode metal film 24 via the bonding layer 32 while being directly bonded to the electrode metal film 24.
  • the bonding layer 32 can form a compound layer containing tin in the P-type thermoelectric conversion element film 51 and the low-temperature-side electrode metal film 24, thereby ensuring bondability and the above compound
  • the layer exhibits an effect as a diffusion preventing layer.
  • thermoelectric conversion module first, only the P-type thermoelectric conversion element film 51 is directly bonded on the high-temperature side electrode metal film 23 and only the N-type thermoelectric conversion element film 52 is formed on the low-temperature side electrode metal film 24. Are directly bonded, and thereafter, bonding is performed via the bonding layer 32.
  • thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are bonded on the high temperature side electrode metal film 23 or the low temperature side electrode metal film 24 (for example, FIG. Compared with the reference), the warpage of the high temperature side substrate 21 and the low temperature side substrate 22 can be reduced.
  • thermoelectric conversion module since the element arrangement is not manually arranged, the P-type thermoelectric element and the N-type thermoelectric element are not interchanged. Details of the manufacturing method will be described in a manufacturing method of a thermoelectric conversion module described later.
  • thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23
  • one bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24.
  • thermoelectric conversion element film 51 is bonded to the low temperature side electrode metal film 24 via the bonding layer 32, and only one bonding surface of the N-type thermoelectric conversion element film 52 is bonded to the bonding layer 32. Therefore, the amount of the bonding material used for manufacturing the bonding layer 32 is reduced, and the cost of the thermoelectric conversion module can be reduced.
  • the aerosol deposition method described above is a film forming method characterized by injecting a material while roughening the surface of a base material and forming a film on the surface of the injected target.
  • the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 enter the high-temperature-side electrode metal film 23 or the low-temperature-side electrode metal film 24 made of copper and adhere to each other without voids and peeling. It has been confirmed with a microscope, and the adhesion strength is about 50 MPa, which is equivalent to the case of joining with an active brazing material.
  • thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are firmly and directly bonded to the high-temperature side electrode metal film 24. .
  • thermoelectric conversion module in which the P-type thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23 and the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24 is exemplified.
  • a thermoelectric conversion module in which the thermoelectric conversion element film 51 is directly bonded to the low temperature side electrode metal film 24 and the N type thermoelectric conversion element film 52 is directly bonded to the high temperature side electrode metal film 23 may be used. [Improvement of thermoelectric conversion module performance]
  • thermoelectric conversion material The performance of the thermoelectric conversion material is expressed by (Equation 1), where Z is a figure of merit.
  • Z S 2 / ⁇ (Equation 1)
  • Z is a thermoelectric figure of merit
  • S is a Seebeck coefficient
  • is electrical resistivity
  • thermal conductivity
  • thermoelectric conversion material having high thermoelectric performance is a material having a large Seebeck coefficient S, a low electrical resistivity ⁇ , and a low thermal conductivity ⁇ .
  • these factors are all electronic functions, they are linked, and in order to obtain a thermoelectric conversion material with high thermoelectric performance, a material composition that provides an optimum electron concentration is required.
  • thermoelectric conversion element of the thermoelectric conversion module is bonded to the metal electrode film via the bonding layer.
  • the contact resistance exists at the interface between the thermoelectric conversion element and the bonding layer, the generated power is reduced. Therefore, the interface between the thermoelectric conversion element and the bonding layer needs to be bonded so that no contact resistance is generated.
  • the generated power P of the thermoelectric conversion material is obtained by multiplying the electromotive force V and the current I.
  • V S ⁇ ⁇ T (Equation 2)
  • P S ⁇ ⁇ T ⁇ I (Equation 3)
  • (Equation 3) represents the case where there is no resistance inside the thermoelectric conversion module.
  • ⁇ T represents the temperature difference between the junction layer / thermoelectric conversion element / junction layer
  • R represents the internal resistance
  • thermoelectric conversion module In the description of [Improvement of performance of thermoelectric conversion module], the structure of a thermoelectric conversion module having bonding layers on both sides of the thermoelectric conversion element has been described. [Method of manufacturing thermoelectric conversion module]
  • thermoelectric conversion module according to the present embodiment will be described with reference to FIGS. 2 to 6 are cross-sectional views of relevant parts for explaining the manufacturing process of the thermoelectric conversion module according to the present embodiment.
  • a mask pattern 61 made of, for example, a resin is formed on the high temperature side substrate 21 on which the high temperature side electrode metal film 23 is formed, and the high temperature side electrode metal film 23 is formed using an aerosol deposition method.
  • a P-type thermoelectric conversion element film 51 is formed thereon (high temperature side element portion HP).
  • a mask pattern 61 made of, for example, a resin is formed on the low-temperature side substrate 22 on which the low-temperature side electrode metal film 24 is formed, and N-type thermoelectric conversion is performed on the low-temperature side electrode metal film 24 using an aerosol deposition method.
  • An element film 52 is formed (low temperature side element portion LP).
  • the carrier gas is nitrogen
  • the gas flow rate is 12 liters / minute
  • the deposition pressure is 150 Pa to 350 Pa
  • the deposition temperature is room temperature.
  • the film thickness of the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 is in the range of 10 ⁇ m to 1,000 ⁇ m.
  • thermoelectric conversion element film 51 is directly bonded on the high-temperature side electrode metal film 23
  • N-type thermoelectric conversion element film 52 is directly bonded on the low-temperature side electrode metal film 24.
  • thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are bonded on the high-temperature side electrode metal film 23, or the P-type thermoelectric conversion element film 51 and the N-type on the low-temperature side electrode metal film 24. Compared with the case where both of the thermoelectric conversion element films 52 are bonded, warpage of the high temperature side substrate 21 and the low temperature side substrate 22 is reduced.
  • the bonding material 31 is formed on the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52, respectively, using an aerosol deposition method.
  • the bonding material 31 is made of tin-silver-copper solder. Thereafter, the mask pattern 61 is removed.
  • the bonding material 31 may be a bonding material such as solder having another composition as long as it functions as a bonding material.
  • the low temperature side substrate 22 having the N-type thermoelectric conversion element film 52 and the like is placed on the support jig 43 with the surface having the N-type thermoelectric conversion element film 52 facing upward.
  • the bonding material 31 on the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 are in contact with each other, and the N-type thermoelectric conversion element film 52 is
  • the high temperature side substrate 21 having the P-type thermoelectric conversion element film 51 and the like is placed on the low temperature side substrate 22 having the N type thermoelectric conversion element film 52 and the like so that the connecting material 31 and the high temperature side electrode metal film 23 are in contact with each other. Install.
  • pressurization is performed from above by the pressurizing jig 44 and heating is performed, and the high-temperature side electrode metal film 23, the N-type thermoelectric conversion element film 52, and the low-voltage side electrode metal film 24. And the P-type thermoelectric conversion element film 51 are collectively bonded through the bonding material 31.
  • the joining temperature can be exemplified by 250 ° C. and the pressurization can be exemplified by 0.5 KPa.
  • the bonding atmosphere may be a non-oxidizing atmosphere, and a vacuum atmosphere, a nitrogen atmosphere, a nitrogen-hydrogen mixed atmosphere, or the like can be used.
  • the bonding temperature varies depending on the atmospheric pressure in the chamber, but may be a temperature at which the bonding material melts, and is desirably as low as possible.
  • the chamber is a furnace used when the bonding material and the member to be bonded are bonded, and is filled with nitrogen. Oxidation of the bonding material or the like is prevented by filling with nitrogen, and the molten bonding material and the member to be bonded are bonded by heating.
  • the gas to be filled may not be nitrogen, but may be another gas as long as oxidation of the bonding material can be prevented.
  • the bonding material 31 when a member capable of diffusion bonding is used as the bonding material 31, it is not necessarily just the melting temperature of the member, and may be higher than the temperature at which diffusion bonding is performed.
  • the bonding material 31 includes a diffusion reaction between the high-temperature side electrode metal film 23 and the N-type thermoelectric conversion element film 52 during bonding, and the low-voltage side electrode metal film 24 and the P-type thermoelectric.
  • the bonding layer 32 is formed by a diffusion reaction with the components of the conversion element film 51.
  • the high temperature side substrate 21 and the low temperature side substrate caused by the internal stress of the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are collectively bonded to the low temperature side substrate 22 on which only the film 52 is formed. 22 warpage can be reduced.
  • the number of times of joining may be one, the number of times of exposure to high temperature can be reduced. Furthermore, since the bonding material is disposed only on one side with respect to the thermoelectric element, the pressure applied is reduced. That is, the thermoelectric element is hardly broken at the time of joining.
  • thermoelectric conversion element film 51 since only the P-type thermoelectric conversion element film 51 is formed on the high-temperature side electrode metal film 23 and only the N-type thermoelectric conversion element film 52 is formed on the low-temperature side electrode metal film 24, the P-type thermoelectric conversion element Since misalignment or misalignment of the film 51 and the N-type thermoelectric conversion element film 52 can be avoided, the manufacturing yield of the thermoelectric conversion module is improved.
  • thermoelectric conversion element film 51 is bonded to the low temperature side electrode metal film 24 via the bonding layer 32, and only one bonding surface of the N-type thermoelectric conversion element film 52 is bonded to the bonding layer 32. Therefore, the amount of the bonding material used for manufacturing the bonding layer 32 is reduced, and the cost of the thermoelectric conversion module can be reduced.
  • thermoelectric conversion module when a resin such as polyimide is used for the high temperature side substrate 21 and the low temperature side substrate 22 and tin-silver-copper solder is used for the bonding layer 32, the high temperature side is 200. It is limited to use in a low temperature range up to about ° C. This depends on the melting temperature of the tin-silver-copper solder. Since polyimide can be used at a temperature up to about 300 ° C., the present invention can be carried out at about 300 ° C. by using a material whose bonding material does not melt at a temperature higher than 200 ° C. [Output of thermoelectric conversion module]
  • thermoelectric conversion module according to the present example The results of comparing the output of the thermoelectric conversion module according to the present example and the output of the thermoelectric conversion module having the bonding layers on both sides of the thermoelectric conversion element, which the present inventors examined as a comparative example, will be described below.
  • a configuration of a thermoelectric conversion module examined by the present inventors as a comparative example is shown in FIG.
  • the P-type thermoelectric conversion element 53 and the N-type thermoelectric conversion element 54 constituting the thermoelectric conversion module according to the comparative example are manufactured by sintering a thermoelectric conversion material.
  • thermoelectric conversion material is iron-vanadium-aluminum
  • the cross-sectional area is 1.0 ⁇ 10 ⁇ 6 m 2
  • the thickness is 25 ⁇ 10 ⁇ 6 m
  • the thermal conductivity is 4.5 W / m ⁇ K
  • the electrical conductivity is 1 ⁇ 10 ⁇ . 5 ⁇ ⁇ m.
  • the bonding material is tin-silver-copper solder
  • the cross-sectional area is 1.0 ⁇ 10 ⁇ 6 m 2
  • the thickness is 5 ⁇ 10 ⁇ 6 m to 25 ⁇ 10 ⁇ 6 m
  • the thermal conductivity is 55.0 W / m. K
  • Rth represents the bonding material thermal resistance
  • ⁇ c represents the bonding material thermal conductivity
  • A represents the bonding material cross-sectional area
  • t represents the bonding material thickness
  • the output power is represented by an output power ratio that is a value obtained by dividing the output power of the thermoelectric conversion element having the bonding material by the output power of the thermoelectric conversion element alone.
  • the output Pi does not include contact resistance.
  • Equation 7 is derived from the above (Equation 5).
  • S is the Seebeck coefficient
  • is the element electrical resistivity
  • A is the element cross-sectional area
  • 10 is the element thickness
  • ⁇ T is the temperature difference between both ends of the single element.
  • thermoelectric conversion element is proportional to the square of the Seebeck coefficient S, and the temperature difference ⁇ T applied to both ends of the thermoelectric conversion element is the maximum factor that determines the element output. I understand.
  • the output Pc of the thermoelectric conversion element having contact resistance (bonding material) is shown in (Equation 8).
  • is the element electric resistivity
  • ⁇ c is the bonding material electric resistivity
  • 10 is the element thickness
  • lc is the bonding material thickness
  • is the element thermal conductivity
  • ⁇ c is the bonding material thermal conductivity
  • the output Pc indicates a state in which the output Pi includes contact resistance and thermal resistance, and is derived by the ratio of the resistance increase due to the bonding material.
  • Equation 8 derives the output of the thermoelectric conversion module according to the comparative example having the bonding material on both surfaces of the thermoelectric conversion element.
  • Equation 9 shows the output calculation of the thermoelectric conversion module according to the present example having the bonding material on one side of the thermoelectric conversion element.
  • FIG. 8 is a graph showing the output power ratio of the thermoelectric conversion module according to the present embodiment and the thermoelectric conversion module according to the comparative example.
  • the vertical axis in FIG. 8 represents the output power ratio, and the horizontal axis represents the thickness of the bonding material.
  • thermoelectric conversion module according to this example can improve the output by 3.2% when the bonding material thickness is 0.005 mm, compared with the thermoelectric conversion module according to the comparative example.
  • the output can be improved by 8.4%.
  • thermoelectric conversion module according to the present embodiment having the bonding material on one side of the thermoelectric conversion element can improve the power generation as compared with the thermoelectric conversion module according to the comparative example having the bonding material on both sides of the thermoelectric conversion element.
  • thermoelectric conversion module according to Modification 1 will be described below with reference to FIG.
  • FIG. 9 is a main part side view showing the vicinity of the elements of the thermoelectric conversion module according to the first modification.
  • thermoelectric conversion module according to the modified example 1 differs from the thermoelectric conversion module shown in FIG. 1 described above.
  • the structure of the connecting portion connecting the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 and the N-type thermoelectric is a structure of a connection portion for connecting the conversion element film 52 and the high temperature side electrode metal film 23.
  • the connecting portion is constituted by a bonding layer 32.
  • the connecting portion includes the bonding material 31 and the bonding layer 32, and the bonding material 31 is left in a part.
  • thermoelectric conversion module shown in FIG. 1 pressurization and heating are performed using the support jig 43 and the pressurization jig 44, and the bonding material 31 is entirely changed to the bonding layer 32. 31 may remain. Also in this case, substantially the same effect as the thermoelectric conversion module shown in FIG. 1 described above can be obtained. (Modification 2)
  • thermoelectric conversion module according to Modification 2 will be described below with reference to FIG.
  • FIG. 10 is a main part side view showing the vicinity of the elements of the thermoelectric conversion module according to the second modification.
  • thermoelectric conversion module according to the modified example 2 differs from the thermoelectric conversion module shown in FIG. 1 described above.
  • the structure of the connecting portion connecting the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 and the N-type thermoelectric is a structure of a connection portion for connecting the conversion element film 52 and the high temperature side electrode metal film 23.
  • the connecting portion is constituted by a bonding layer 32.
  • the connection portion is formed by stacking the metal layer 33 and the bonding layer 32. That is, the metal layer 33 is formed between the bonding layer 32 and the P-type thermoelectric conversion element film 51 and between the bonding layer 32 and the N-type thermoelectric conversion element film 52.
  • the metal layer 33 is a metal layer made of, for example, titanium, nickel, chromium, or cobalt, or a metal layer mainly composed of any one of these metals.
  • the main component refers to a component having the highest content rate in a member containing a plurality of elements.
  • the metal film 33 has a function of preventing diffusion of elements constituting the bonding layer 32 into the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52.
  • the metal layer 33 functioning as a diffusion prevention film is formed so as to be laminated with the bonding layer 32, thereby suppressing doping of the impurity element into the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52. Therefore, it is possible to prevent a decrease in thermoelectric characteristics (electromotive force) of the thermoelectric module due to deterioration of the thermoelectric performance of the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52.
  • Modification 3 A thermoelectric conversion module according to Modification 3 will be described below.
  • thermoelectric conversion module according to the modification 3 The difference between the thermoelectric conversion module according to the modification 3 and the thermoelectric conversion module shown in FIG. 1 described above is the material of the high temperature side substrate 21 and the low temperature side substrate 22 and the material of the bonding layer 32.
  • thermoelectric conversion module shown in FIG. 1 described above, a resin such as polyimide is used for the high temperature side substrate 21 and the low temperature side substrate 22, and tin-silver-copper solder is used for the bonding layer 32.
  • a resin such as polyimide
  • tin-silver-copper solder is used for the bonding layer 32.
  • ceramics such as alumina is used for the high temperature side substrate 21 and the low temperature side substrate 22, and copper is used for the bonding layer 32.
  • the thickness of the ceramic is, for example, about 0.3 mm.
  • the thermoelectric conversion module can be used even in the middle / high temperature range of about 300 ° C. to 600 ° C.
  • thermoelectric conversion module by the modification 3 can improve electric power generation rather than the thermoelectric conversion module shown in FIG. 1 mentioned above. Further, since the melting point of copper is as high as 1,085 ° C., the thermoelectric conversion module can be used also in the middle / high temperature range of about 300 ° C. to 600 ° C.
  • thermoelectric conversion module that can be used in a low, medium, and high temperature range of about 200 ° C. to 600 ° C.

Abstract

To provide a thermoelectric conversion module having improved reliability and thermoelectric performance. In order to solve the above-mentioned problem, in a thermoelectric conversion module of the present invention, a first bonding surface of a P-type thermoelectric conversion element film is directly bonded to a high temperature-side electrode metal film formed on a high temperature-side substrate, and a second bonding surface on the reverse side of the first bonding surface is bonded to a low temperature-side electrode metal film by having a bonding layer therebetween. Furthermore, a first bonding surface of an N-type thermoelectric conversion element film is directly bonded to a low temperature-side electrode metal film formed on a low temperature-side substrate, and a second bonding surface on the reverse side of the first bonding surface is bonded to the high temperature-side electrode metal film by having the bonding layer therebetween.

Description

熱電変換モジュールおよびその製造方法Thermoelectric conversion module and manufacturing method thereof
 本発明は、熱電変換モジュールおよびその製造方法に関する。 The present invention relates to a thermoelectric conversion module and a manufacturing method thereof.
 本技術分野の背景技術として、特開2003-133600号公報(特許文献1)がある。この公報には、柔軟性を有する基板の表面上に、P型熱電変換素子層とN型熱電変換素子層とを形成した熱電変換部材が記載されており、熱電変換部材自体、柔軟性を有している。 As a background art in this technical field, there is JP-A-2003-133600 (Patent Document 1). This publication describes a thermoelectric conversion member in which a P-type thermoelectric conversion element layer and an N-type thermoelectric conversion element layer are formed on the surface of a flexible substrate. The thermoelectric conversion member itself has flexibility. is doing.
特開2003-133600号公報JP 2003-133600 A
 近年、フレキシブル基板上に熱電変換素子膜を形成することにより、フレキシブル性を有する熱電変換モジュールが提案されている。しかし、熱電変換素子膜の内部応力等に起因したフレキシブル基板の反りにより、所望する信頼性および熱電性能(変換性能、発電性能とも言う。)を有する熱電変換モジュールが得られないという課題がある。 Recently, a thermoelectric conversion module having flexibility has been proposed by forming a thermoelectric conversion element film on a flexible substrate. However, there is a problem that a thermoelectric conversion module having desired reliability and thermoelectric performance (also referred to as conversion performance or power generation performance) cannot be obtained due to warping of the flexible substrate caused by internal stress of the thermoelectric conversion element film.
 上記課題を解決するために、本発明の熱電変換モジュールは、P型熱電変換素子膜の第1接合面を、高温側基板上に形成された高温側電極金属膜と直接接合し、第1接合面と反対側の第2接合面を、接合層を介して低温側電極金属膜と接合する。また、N型熱電変換素子膜の第1接合面を、低温側基板上に形成された低温側電極金属膜と直接接合し、第1接合面と反対側の第2接合面を、接合層を介して高温側電極金属膜と接合する。 In order to solve the above-described problem, the thermoelectric conversion module of the present invention directly joins the first joining surface of the P-type thermoelectric conversion element film with the high-temperature side electrode metal film formed on the high-temperature side substrate. The second bonding surface opposite to the surface is bonded to the low-temperature electrode metal film through the bonding layer. Further, the first bonding surface of the N-type thermoelectric conversion element film is directly bonded to the low temperature side electrode metal film formed on the low temperature side substrate, and the second bonding surface opposite to the first bonding surface is bonded to the bonding layer. To the high temperature side electrode metal film.
 本発明によれば、信頼性および熱電性能の向上した熱電変換モジュールを提供することができる。
 上記した以外の課題、構成および効果は、以下の実施の形態の説明により明らかにされる。
According to the present invention, a thermoelectric conversion module with improved reliability and thermoelectric performance can be provided.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
本実施例による熱電変換モジュールの素子近傍を示す要部側面図である。It is a principal part side view which shows the element vicinity of the thermoelectric conversion module by a present Example. 本実施例による熱電変換モジュールの製造工程を示す要部断面図である。It is principal part sectional drawing which shows the manufacturing process of the thermoelectric conversion module by a present Example. 図2に続く、熱電変換モジュールの製造工程を示す要部断面図である。FIG. 3 is a main part cross-sectional view showing the manufacturing process of the thermoelectric conversion module following FIG. 2; 図3に続く、熱電変換モジュールの製造工程を示す要部断面図である。FIG. 4 is a main part cross-sectional view showing the manufacturing process of the thermoelectric conversion module following FIG. 3; 図4に続く、熱電変換モジュールの製造工程を示す要部断面図である。FIG. 5 is a main-portion cross-sectional view illustrating the manufacturing process of the thermoelectric conversion module following FIG. 4. 図5に続く、熱電変換モジュールの製造工程を示す要部断面図である。FIG. 6 is a cross-sectional view of the principal part showing the manufacturing process of the thermoelectric conversion module following FIG. 5. 本発明者らが比較例として検討した熱電変換モジュールの素子近傍を示す要部側面図である。It is a principal part side view which shows the element vicinity of the thermoelectric conversion module which the present inventors examined as a comparative example. 本実施例による熱電変換モジュールおよび比較例による熱電変換モジュールの出力電力比を示すグラフ図である。It is a graph which shows the output power ratio of the thermoelectric conversion module by a present Example, and the thermoelectric conversion module by a comparative example. 変形例1による熱電変換モジュールの素子近傍を示す要部側面図である。It is a principal part side view which shows the element vicinity of the thermoelectric conversion module by the modification 1. FIG. 変形例2による熱電変換モジュールの素子近傍を示す要部側面図である。It is a principal part side view which shows the element vicinity of the thermoelectric conversion module by the modification 2.
 以下の実施の形態において、便宜上その必要があるときは、複数のセクションまたは実施の形態に分割して説明するが、特に明示した場合を除き、それらはお互いに無関係なものではなく、一方は他方の一部または全部の変形例、詳細、補足説明等の関係にある。 In the following embodiments, when necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other, and one is the other. There are some or all of the modifications, details, supplementary explanations, and the like.
 また、以下の実施の形態において、要素の数等(個数、数値、量、範囲等を含む)に言及する場合、特に明示した場合および原理的に明らかに特定の数に限定される場合等を除き、その特定の数に限定されるものではなく、特定の数以上でも以下でもよい。 Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.
 また、以下の実施の形態において、その構成要素(要素ステップ等も含む)は、特に明示した場合および原理的に明らかに必須であると考えられる場合等を除き、必ずしも必須のものではないことは言うまでもない。 Further, in the following embodiments, the constituent elements (including element steps) are not necessarily indispensable unless otherwise specified and clearly considered essential in principle. Needless to say.
 また、「Aからなる」、「Aよりなる」、「Aを有する」、「Aを含む」と言うときは、特にその要素のみである旨明示した場合等を除き、それ以外の要素を排除するものでないことは言うまでもない。同様に、以下の実施の形態において、構成要素等の形状、位置関係等に言及するときは、特に明示した場合および原理的に明らかにそうでないと考えられる場合等を除き、実質的にその形状等に近似または類似するもの等を含むものとする。このことは、上記数値および範囲についても同様である。 In addition, when referring to “consisting of A”, “consisting of A”, “having A”, and “including A”, other elements are excluded unless specifically indicated that only that element is included. It goes without saying that it is not what you do. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.
 また、以下の実施の形態で用いる図面においては、側面図であっても図面を見易くするためにハッチングを付す場合もある。また、以下の実施の形態を説明するための全図において、同一機能を有するものは原則として同一の符号を付し、その繰り返しの説明は省略する。以下、本実施の形態を図面に基づいて詳細に説明する。 Also, in the drawings used in the following embodiments, hatching may be added to make the drawings easy to see even if they are side views. In all the drawings for explaining the following embodiments, components having the same function are denoted by the same reference numerals in principle, and repeated description thereof is omitted. Hereinafter, the present embodiment will be described in detail with reference to the drawings.
 また、以下の実施の形態において、熱電変換素子膜とは、エアロゾルデポジション法等によって成膜した熱電素子を言う。本願明細書においては、特に断わりなく熱電変換素子膜を熱電素子として説明することがある。 In the following embodiments, the thermoelectric conversion element film refers to a thermoelectric element formed by an aerosol deposition method or the like. In the present specification, the thermoelectric conversion element film may be described as a thermoelectric element without particular notice.
 熱電変換モジュールは、環境調和型社会の実現に向けて、排熱を熱エネルギーとして回収できる手法として注目が集まっており、低温域では腕時計、温泉等、中・高温域では焼却炉、工業炉、自動車等の関連製品等への展開が検討されている。 Thermoelectric conversion modules are attracting attention as a method for recovering exhaust heat as thermal energy for the realization of an environmentally harmonious society. Watches and hot springs are used at low temperatures, incinerators, industrial furnaces, Expansion to related products such as automobiles is under consideration.
 排熱のエネルギー利用を考慮すると、排熱は、さまざまな場面で生じるため、熱電変換モジュールは、設置形態における汎用性の高い構造にする必要がある。また、熱電変換モジュールは、高温側の基板と低温側の基板との間に、P型熱電変換素子とN型熱電変換素子とを直列・交互に配置した、いわゆるπ型構造を主に採る。このため、熱電変換モジュールは、組立時に、P型熱電変換素子およびN型熱電変換素子を1箇所でも並べ違えると、電流が流れず、動作しないことがある。そのため、製造プロセスの簡略化と、製造ミスのないプロセスを確立することは重要な課題である。さらに、現在実用化されている熱電変換材料、例えばビスマス-テルル系材料を用いた溶製材または焼結材は、強度が低く、加工性が低いという課題を有している。 考慮 す る Considering the use of exhaust heat energy, exhaust heat occurs in various situations, so the thermoelectric conversion module needs to have a highly versatile structure in the installation form. The thermoelectric conversion module mainly adopts a so-called π-type structure in which P-type thermoelectric conversion elements and N-type thermoelectric conversion elements are arranged in series and alternately between a high temperature side substrate and a low temperature side substrate. For this reason, if the P-type thermoelectric conversion element and the N-type thermoelectric conversion element are rearranged even at one place during assembly, the thermoelectric conversion module may not operate because it does not flow. Therefore, it is an important issue to simplify the manufacturing process and establish a process without manufacturing errors. Furthermore, a melted material or a sintered material using a thermoelectric conversion material that is currently in practical use, such as a bismuth-tellurium-based material, has a problem of low strength and low workability.
 前記特許文献1には、柔軟性(フレキシブル)を有する樹脂基板上に、直接熱電変換素子層を蒸着によって形成することにより、素子配列および素子加工の歩留りが向上し、かつ設置形態における汎用性の高いフレキシブル構造の熱電変換モジュールの製造方法が記載されている(図5参照)。 In Patent Document 1, by directly forming a thermoelectric conversion element layer on a flexible resin substrate by vapor deposition, the yield of element arrangement and element processing is improved, and the versatility of the installation form is improved. A manufacturing method of a thermoelectric conversion module having a high flexible structure is described (see FIG. 5).
 しかしながら、前記特許文献1では、高温側または低温側のどちらか一方のフレキシブル基板の面上に、複数のP型およびN型熱電変換素子層が蒸着によって形成される。蒸着でP型およびN型熱電変換素子層を同一面上に同一ピッチで形成するには、例えばP型熱電変換素子をP型熱電変換素子膜形成用の蒸着マスクを用いて形成した後、N型熱電変換素子膜形成用の蒸着マスクの位置合せをピッチずれがないように厳密に行ない、その後、N型熱電変換素子を形成しなければならない。この位置合せには高度な技術が求められ、本製造プロセスにおいて最も煩雑な工程である。また、複数のP型およびN型熱電変換素子層が形成された面側に応力が集中して、フレキシブル基板が反ることが懸念される。 However, in Patent Document 1, a plurality of P-type and N-type thermoelectric conversion element layers are formed by vapor deposition on the surface of either the high-temperature side or the low-temperature side flexible substrate. In order to form the P-type and N-type thermoelectric conversion element layers at the same pitch on the same surface by vapor deposition, for example, after forming the P-type thermoelectric conversion element using a vapor deposition mask for forming a P-type thermoelectric conversion element film, N The alignment of the deposition mask for forming the type thermoelectric conversion element film must be strictly performed so that there is no pitch shift, and then the N type thermoelectric conversion element must be formed. This alignment requires a high level of technology, and is the most complicated step in the manufacturing process. In addition, there is a concern that stress concentrates on the surface side on which a plurality of P-type and N-type thermoelectric conversion element layers are formed, and the flexible substrate warps.
 この反りにより、熱電変換素子層の割れ、熱源への接触面積の減少等が予想され、熱電変換モジュールの信頼性と、熱電性能が低下する場合がある。 This warpage is expected to cause a crack in the thermoelectric conversion element layer, a decrease in the contact area with the heat source, and the like, and may reduce the reliability and thermoelectric performance of the thermoelectric conversion module.
 本願発明は、熱電変換モジュールの信頼性と、熱電性能を向上させる技術を提供することを目的とする。 An object of the present invention is to provide a technique for improving the reliability and thermoelectric performance of a thermoelectric conversion module.
 [熱電変換モジュールの構成]
 本実施例による熱電変換モジュールの構成を、図1を用いて説明する。図1は、本実施例による熱電変換モジュールの素子近傍を示す要部側面図である。図中、符号1は熱電変換モジュール素子組立体、符号51はP型熱電変換素子膜、符号52はN型熱電変換素子膜、符号21は高温側基板、符号22は低温側基板、符号23は高温側電極金属膜、符号24は低温側電極金属膜、符号32は接合層である。
[Configuration of thermoelectric conversion module]
The configuration of the thermoelectric conversion module according to the present embodiment will be described with reference to FIG. FIG. 1 is a side view of an essential part showing the vicinity of an element of a thermoelectric conversion module according to the present embodiment. In the figure, reference numeral 1 is a thermoelectric conversion module element assembly, reference numeral 51 is a P-type thermoelectric conversion element film, reference numeral 52 is an N-type thermoelectric conversion element film, reference numeral 21 is a high-temperature side substrate, reference numeral 22 is a low-temperature side substrate, and reference numeral 23 is Reference numeral 24 denotes a high temperature side electrode metal film, reference numeral 24 denotes a low temperature side electrode metal film, and reference numeral 32 denotes a bonding layer.
 図1に示すように、P型熱電変換素子膜51の第1接合面は、高温側基板21上に形成された高温側電極金属膜23と直接接合し、第1接合面と反対側の第2接合面は、低温側基板22上に形成された低温側電極金属膜24と接合層32を介して接合する。 As shown in FIG. 1, the first bonding surface of the P-type thermoelectric conversion element film 51 is directly bonded to the high temperature side electrode metal film 23 formed on the high temperature side substrate 21, and the first bonding surface on the opposite side to the first bonding surface. The two bonding surfaces are bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22 via the bonding layer 32.
 また、N型熱電変換素子膜52の第1接合面は、低温側基板22上に形成された低温側電極金属膜24と直接接合し、第1接合面と反対側の第2接合面は、高温側基板21上に形成された高温側電極金属膜23と接合層32を介して接合する。 Further, the first bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22, and the second bonding surface opposite to the first bonding surface is The high temperature side electrode metal film 23 formed on the high temperature side substrate 21 is bonded via the bonding layer 32.
 本実施例では、P型熱電変換素子膜51は、蒸着法、スパッタリング法、エアロゾルデポジション法または印刷法のいずれかを用いて高温側電極金属膜23上に直接形成され、N型熱電変換素子膜52は、蒸着法、スパッタリング法、エアロゾルデポジション法または印刷法のいずれかを用いて低温側電極金属膜24上に直接形成される。 In the present embodiment, the P-type thermoelectric conversion element film 51 is directly formed on the high-temperature side electrode metal film 23 using any one of a vapor deposition method, a sputtering method, an aerosol deposition method, and a printing method. The film 52 is directly formed on the low-temperature electrode metal film 24 using any one of a vapor deposition method, a sputtering method, an aerosol deposition method, and a printing method.
 高温側電極金属膜23および低温側電極金属膜24は、それぞれ高温側基板21および低温側基板22上にパターン加工されていればよく、その形成方法は問わない。 The high temperature side electrode metal film 23 and the low temperature side electrode metal film 24 may be patterned on the high temperature side substrate 21 and the low temperature side substrate 22, respectively, and the formation method thereof is not limited.
 高温側電極金属膜23および低温側電極金属膜24は、電気伝導度および熱伝導度が高く、電極部材として適している90質量%以上の銅で構成されることが好ましい。 The high temperature side electrode metal film 23 and the low temperature side electrode metal film 24 are preferably composed of 90% by mass or more of copper, which has high electrical conductivity and thermal conductivity and is suitable as an electrode member.
 但し、高温側電極金属膜23および低温側電極金属膜24が厚すぎると、熱電変換モジュール稼働時に発生する熱膨張応力が大きくなることから、その膜厚は、0.5mm以下とすることが好ましい。その一方で、高温側電極金属膜23および低温側電極金属膜24が薄すぎると、電流が流れにくくなることから、その膜厚は、1.0μm以上とすることが好ましい。 However, if the high-temperature side electrode metal film 23 and the low-temperature side electrode metal film 24 are too thick, the thermal expansion stress generated during operation of the thermoelectric conversion module increases, so the film thickness is preferably 0.5 mm or less. . On the other hand, if the high temperature side electrode metal film 23 and the low temperature side electrode metal film 24 are too thin, it becomes difficult for current to flow. Therefore, the film thickness is preferably 1.0 μm or more.
 P型熱電変換素子膜51およびN型熱電変換素子膜52は、300℃~1,000℃程度の範囲で使用を想定した熱電変換モジュールの場合は、上記温度範囲内で発電性能が高いシリコン-ゲルマニウム系、マグネシウム-シリコン系、マンガン-シリコン系、鉛-テルル系、スクッテルダイト系、ハーフホイスラー合金系のいずれかの組み合わせからなる熱電変換素子膜が好ましい。室温(27℃程度)~300℃程度の範囲で使用を想定した熱電変換モジュールの場合は、ホイスラー合金系、ビスマス-テルル系が発電性能の点から好ましい。 The P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 have a high power generation performance within the above temperature range in the case of a thermoelectric conversion module assumed to be used in the range of about 300 ° C. to 1,000 ° C. A thermoelectric conversion element film made of any combination of germanium, magnesium-silicon, manganese-silicon, lead-tellurium, skutterudite, and half-Heusler alloy is preferred. In the case of a thermoelectric conversion module assumed to be used in the range of room temperature (about 27 ° C.) to about 300 ° C., a Heusler alloy system and a bismuth-tellurium system are preferable from the viewpoint of power generation performance.
 本実施例における代表的な例としては、P型熱電変換素子膜51およびN型熱電変換素子膜52は、600℃程度まで高い耐酸化性を示し、1,150℃程度までホイスラー構造が安定であるホイスラー合金の鉄-バナジウム-アルミニウムを挙げることができる。 As a typical example in this embodiment, the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 have high oxidation resistance up to about 600 ° C., and the Heusler structure is stable up to about 1,150 ° C. Mention may be made of iron-vanadium-aluminum of certain Heusler alloys.
 本実施例では、P型熱電変換素子膜51およびN型熱電変換素子膜52を、主としてエアロゾルデポジション法を用いて形成する。 In this embodiment, the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are mainly formed by using an aerosol deposition method.
 エアロゾルデポジション法は、微粒子化したナノオーダーの熱電変換材料粒子を、基材に衝突させることにより熱電変換素子膜を形成する方法である。熱電変換素子膜には、粒子衝突による衝突を拡大させようとする力と、粒子衝突の影響のない基材内部からの拘束力が同時に働く。 The aerosol deposition method is a method of forming a thermoelectric conversion element film by colliding nanosized thermoelectric conversion material particles into a base material. In the thermoelectric conversion element film, a force for expanding the collision caused by the particle collision and a restraining force from the inside of the base material without the influence of the particle collision work simultaneously.
 そのため、熱電変換素子膜の内部には圧縮応力が残留し、基材にはその応力につりあうように引張応力が残留する。 Therefore, a compressive stress remains inside the thermoelectric conversion element film, and a tensile stress remains on the base material so as to balance the stress.
 しかし、この内部応力が大きいと熱電変換素子膜の内部で割れが発生する。このため、エアロゾルデポジション法によりP型熱電変換素子膜51およびN型熱電変換素子膜52を形成する場合は、その膜厚は、10μm~1,000μmの範囲とすることが好ましい。10μmよりも薄くなると、熱電素子と電極とを接続するためのはんだ厚の制御が難しく、接合の際には、はんだが溶出して短絡する恐れがある。1,000μmよりも厚くなると、熱電変換素子膜が割れる恐れがある。 However, if this internal stress is large, cracks occur inside the thermoelectric conversion element film. Therefore, when the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are formed by the aerosol deposition method, the film thickness is preferably in the range of 10 μm to 1,000 μm. If the thickness is less than 10 μm, it is difficult to control the thickness of the solder for connecting the thermoelectric element and the electrode, and there is a risk that the solder will elute and short-circuit at the time of joining. If it is thicker than 1,000 μm, the thermoelectric conversion element film may break.
 接合層32は、アルミニウム、インジウム、亜鉛、錫、金またはゲルマニウム等の金属、あるいははんだからなる。接合層32の形成方法は、蒸着法、スパッタリング法、エアロゾルデポジション法、溶射法またはイオンプレーティング法等であればよく、その形成方法は問わない。但し、接合層32が薄すぎると、接合強度の低下および未接合部の発生による熱電性能の低下が懸念される。 The bonding layer 32 is made of a metal such as aluminum, indium, zinc, tin, gold or germanium, or solder. The bonding layer 32 may be formed by any method such as vapor deposition, sputtering, aerosol deposition, thermal spraying, or ion plating. However, if the bonding layer 32 is too thin, there is a concern about a decrease in bonding strength and a decrease in thermoelectric performance due to the occurrence of unbonded portions.
 逆に、接合層32が厚すぎると、接合層32の応力によるP型熱電変換素子膜51およびN型熱電変換素子膜52の割れが懸念される。 Conversely, if the bonding layer 32 is too thick, the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 may be cracked due to the stress of the bonding layer 32.
 そのため、接合層32の膜厚は、5.0μm~20.0μmの範囲とすることが好ましい。本実施例における代表的な例として、接合層32は錫を含有する鉛フリーはんだを用いると熱電素子との接合性がよい。特に電極材として、銅の表面にニッケルを形成し、当該はんだで接続をすると安定した信頼性の高い接合層界面を形成することができる。 Therefore, the thickness of the bonding layer 32 is preferably in the range of 5.0 μm to 20.0 μm. As a typical example in the present embodiment, the bonding layer 32 has good bonding properties with thermoelectric elements when lead-free solder containing tin is used. In particular, as an electrode material, when nickel is formed on the surface of copper and connected with the solder, a stable and highly reliable bonding layer interface can be formed.
 高温側基板21および低温側基板22は、ポリイミド、ポリエチレンテレフタレート、ポリサルフォン、ポリエーテルケトン、ポリエチレンまたはポリフェニレンサルファイト等の樹脂、あるいはアルミナ、窒化珪素または窒化アルミニウム等のセラミックス等からなる絶縁性を有する材料が適している。特に樹脂はシート状に製造できる。エアロゾルデポジション法等でまとめて大きいサイズのシート状部材として製造し、適宜必要なサイズに切り出して利用できるため、本発明に適している。 The high temperature side substrate 21 and the low temperature side substrate 22 are insulating materials made of a resin such as polyimide, polyethylene terephthalate, polysulfone, polyether ketone, polyethylene or polyphenylene sulfite, or ceramics such as alumina, silicon nitride, or aluminum nitride. Is suitable. In particular, the resin can be produced in a sheet form. It is suitable for the present invention because it can be manufactured as a large-sized sheet-like member by the aerosol deposition method or the like, cut out to a necessary size, and used as appropriate.
 さらに、高温側基板21および低温側基板22は、同一材料であることが好ましい。これは、高温側基板21の熱膨張係数と低温側基板22の熱膨張係数の差が小さい方が、接合部および熱電変換モジュール全体に発生する応力が低減するので、熱電変換モジュールの反りを抑制できるためである。本実施例における代表的な例として、高温側基板21および低温側基板22はポリイミド樹脂、その膜厚は75μmを挙げることができる。 Furthermore, the high temperature side substrate 21 and the low temperature side substrate 22 are preferably made of the same material. This is because, when the difference between the thermal expansion coefficient of the high temperature side substrate 21 and the thermal expansion coefficient of the low temperature side substrate 22 is smaller, the stress generated in the entire joint portion and the thermoelectric conversion module is reduced, so that the warpage of the thermoelectric conversion module is suppressed. This is because it can. As a typical example in this embodiment, the high temperature side substrate 21 and the low temperature side substrate 22 can be polyimide resin, and the film thickness thereof can be 75 μm.
 前述したように、P型熱電変換素子膜51の第1接合面は、高温側基板21に形成された高温側電極金属膜23と直接接合し、P型熱電変換素子51の第1接合面と反対側の第2接合面は、低温側基板22に形成された低温側電極金属膜24と接合層32を介して接合する。 As described above, the first bonding surface of the P-type thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23 formed on the high-temperature side substrate 21, and the first bonding surface of the P-type thermoelectric conversion element 51 is The second bonding surface on the opposite side is bonded to the low temperature side electrode metal film 24 formed on the low temperature side substrate 22 via the bonding layer 32.
 一方、N型熱電変換素子膜52の第1接合面は、低温側基板22に形成された低温側電極金属膜24と直接接合し、N型熱電変換素子52の第1接合面と反対側の第2接合面は、高温側基板21に形成された高温側電極金属膜23と接合層32を介して接合する。 On the other hand, the first bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24 formed on the low-temperature side substrate 22, and is opposite to the first bonding surface of the N-type thermoelectric conversion element 52. The second bonding surface is bonded to the high temperature side electrode metal film 23 formed on the high temperature side substrate 21 via the bonding layer 32.
 言い換えると、熱電変換モジュールは、一つの高温側電極金属膜23上に、P型熱電変換素子膜51およびN型熱電変換素子膜52が接合されるが、P型熱電変換素子膜51は高温側電極金属膜23と直接接合し、N型熱電変換素子膜52は接合層32を介して高温側電極金属膜23と接合する。 In other words, in the thermoelectric conversion module, the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are joined on one high-temperature side electrode metal film 23. The N type thermoelectric conversion element film 52 is bonded to the high temperature side electrode metal film 23 through the bonding layer 32.
 同様に、熱電変換モジュールは、一つの低温側電極金属膜24上に、P型熱電変換素子膜51およびN型熱電変換素子膜52が接合されるが、N型熱電変換素子膜52は低温側電極金属膜24と直接接合し、P型熱電変換素子膜51は接合層32を介して低温側電極金属膜24と接合する。 Similarly, in the thermoelectric conversion module, a P-type thermoelectric conversion element film 51 and an N-type thermoelectric conversion element film 52 are bonded on one low-temperature side electrode metal film 24, but the N-type thermoelectric conversion element film 52 is on the low temperature side. The P-type thermoelectric conversion element film 51 is bonded to the low-temperature-side electrode metal film 24 via the bonding layer 32 while being directly bonded to the electrode metal film 24.
 接合後の接合層32は電極側にはんだの成分を含む化合物層が形成され、化合物層上には、使用したはんだの成分が残存する。特に錫を含有する鉛フリーはんだを用いた場合の接合層32は、P型熱電変換素子膜51および低温側電極金属膜24に錫を含む化合物層ができることで、接合性を確保するとともに上記化合物層が、拡散防止層として効果を発揮する。 In the bonded layer 32 after bonding, a compound layer containing a solder component is formed on the electrode side, and the used solder component remains on the compound layer. In particular, when the lead-free solder containing tin is used, the bonding layer 32 can form a compound layer containing tin in the P-type thermoelectric conversion element film 51 and the low-temperature-side electrode metal film 24, thereby ensuring bondability and the above compound The layer exhibits an effect as a diffusion preventing layer.
 すなわち、熱電変換モジュールの製造工程においては、まず、高温側電極金属膜23上にP型熱電変換素子膜51のみが直接接合され、低温側電極金属膜24上にN型熱電変換素子膜52のみが直接接合され、その後、接合層32を介した接合が行われる。 That is, in the manufacturing process of the thermoelectric conversion module, first, only the P-type thermoelectric conversion element film 51 is directly bonded on the high-temperature side electrode metal film 23 and only the N-type thermoelectric conversion element film 52 is formed on the low-temperature side electrode metal film 24. Are directly bonded, and thereafter, bonding is performed via the bonding layer 32.
 従って、高温側電極金属膜23上または低温側電極金属膜24上に、P型熱電変換素子膜51とN型熱電変換素子膜52の両方が接合される場合(例えば前記特許文献1の図5参照)と比較して、高温側基板21および低温側基板22の反りを低減することができる。 Therefore, when both the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are bonded on the high temperature side electrode metal film 23 or the low temperature side electrode metal film 24 (for example, FIG. Compared with the reference), the warpage of the high temperature side substrate 21 and the low temperature side substrate 22 can be reduced.
 これにより、P型熱電変換素子膜51およびN型熱電変換素子膜52の内部応力等に起因した高温側基板21および低温側基板22の反りを低減することができるので、熱電モジュールの信頼性を向上することができる。 As a result, warpage of the high temperature side substrate 21 and the low temperature side substrate 22 due to internal stresses or the like of the P type thermoelectric conversion element film 51 and the N type thermoelectric conversion element film 52 can be reduced. Can be improved.
 また、手作業によって素子配列を並べないため、P型熱電素子とN型熱電素子との入れ替わりも起こらないこととなる。
 その製造方法の詳細は、後述の熱電変換モジュールの製造方法において説明する。
In addition, since the element arrangement is not manually arranged, the P-type thermoelectric element and the N-type thermoelectric element are not interchanged.
Details of the manufacturing method will be described in a manufacturing method of a thermoelectric conversion module described later.
 また、P型熱電変換素子膜51の一方の接合面を高温側電極金属膜23に直接接合し、N型熱電変換素子膜52の一方の接合面を低温側電極金属膜24に直接接合することにより、熱が伝わりやすくなるので、熱電モジュールの熱電性能(起電力)を向上することができる。 Also, one bonding surface of the P-type thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23, and one bonding surface of the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24. Thus, heat can be easily transmitted, so that the thermoelectric performance (electromotive force) of the thermoelectric module can be improved.
 また、P型熱電変換素子膜51の一方の接合面のみを接合層32を介して低温側電極金属膜24と接合し、N型熱電変換素子膜52の一方の接合面のみを接合層32を介して高温側電極金属膜23と接合するので、接合層32の製造に用いる接合材の使用量が減り、熱電変換モジュールの低コスト化が可能となる。 Further, only one bonding surface of the P-type thermoelectric conversion element film 51 is bonded to the low temperature side electrode metal film 24 via the bonding layer 32, and only one bonding surface of the N-type thermoelectric conversion element film 52 is bonded to the bonding layer 32. Therefore, the amount of the bonding material used for manufacturing the bonding layer 32 is reduced, and the cost of the thermoelectric conversion module can be reduced.
 前述したエアロゾルデポジション法は、基材の表面を粗しながら材料を射出し、射出された対象の表面に成膜することを特徴とする成膜方法である。 The aerosol deposition method described above is a film forming method characterized by injecting a material while roughening the surface of a base material and forming a film on the surface of the injected target.
 P型熱電変換素子膜51およびN型熱電変換素子膜52は、銅からなる高温側電極金属膜23または低温側電極金属膜24に入り込み、ボイドおよび剥離を介さずに密着することを透過型電子顕微鏡で確認しており、また、密着強度も活性ろう材で接合した場合と同等の約50MPaを有している。 The P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 enter the high-temperature-side electrode metal film 23 or the low-temperature-side electrode metal film 24 made of copper and adhere to each other without voids and peeling. It has been confirmed with a microscope, and the adhesion strength is about 50 MPa, which is equivalent to the case of joining with an active brazing material.
 よって、エアロゾルデポジション法を用いることにより、P型熱電変換素子膜51は高温側電極金属膜23に、N型熱電変換素子膜52は低温側電極金属膜24に、強固に直接接合すると考えられる。 Therefore, by using the aerosol deposition method, it is considered that the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are firmly and directly bonded to the high-temperature side electrode metal film 24. .
 なお、本実施例では、P型熱電変換素子膜51を高温側電極金属膜23に、N型熱電変換素子膜52を低温側電極金属膜24に直接接合した熱電変換モジュールを例示したが、P型熱電変換素子膜51を低温側電極金属膜24に、N型熱電変換素子膜52を高温側電極金属膜23に直接接合した熱電変換モジュールであってもよい。
 [熱電変換モジュールの性能向上]
In this embodiment, the thermoelectric conversion module in which the P-type thermoelectric conversion element film 51 is directly bonded to the high-temperature side electrode metal film 23 and the N-type thermoelectric conversion element film 52 is directly bonded to the low-temperature side electrode metal film 24 is exemplified. A thermoelectric conversion module in which the thermoelectric conversion element film 51 is directly bonded to the low temperature side electrode metal film 24 and the N type thermoelectric conversion element film 52 is directly bonded to the high temperature side electrode metal film 23 may be used.
[Improvement of thermoelectric conversion module performance]
 熱電変換材料の性能は、性能指数をZとすると、(数1)で表される。
   Z=S/ρκ                 (数1)
The performance of the thermoelectric conversion material is expressed by (Equation 1), where Z is a figure of merit.
Z = S 2 / ρκ (Equation 1)
(数1)において、Zは熱電性能指数、Sはゼーベック係数、ρは電気抵抗率、κは熱伝導率を表わす。 In (Expression 1), Z is a thermoelectric figure of merit, S is a Seebeck coefficient, ρ is electrical resistivity, and κ is thermal conductivity.
 (数1)により、熱電性能の高い熱電変換材料とは、ゼーベック係数Sが大きく、電気抵抗率ρが低く、熱伝導率κが低い材料であることが分かる。しかし、これらの因子は、すべて電子関数となることから、連動しており、熱電性能の高い熱電変換材料を得るには、最適な電子濃度となるような材料組成が必要とされる。 (Equation 1) shows that a thermoelectric conversion material having high thermoelectric performance is a material having a large Seebeck coefficient S, a low electrical resistivity ρ, and a low thermal conductivity κ. However, since these factors are all electronic functions, they are linked, and in order to obtain a thermoelectric conversion material with high thermoelectric performance, a material composition that provides an optimum electron concentration is required.
 熱電変換モジュールの熱電変換素子は、接合層を介して金属電極膜と接合される。熱電変換素子と接合層との界面に接触抵抗が存在すると、発電力が低下するため、熱電変換素子と接合層との界面は、接触抵抗が生じないように接合される必要がある。 The thermoelectric conversion element of the thermoelectric conversion module is bonded to the metal electrode film via the bonding layer. When the contact resistance exists at the interface between the thermoelectric conversion element and the bonding layer, the generated power is reduced. Therefore, the interface between the thermoelectric conversion element and the bonding layer needs to be bonded so that no contact resistance is generated.
 例えば(数2)および(数3)に示すように、熱電変換材料の発電力Pは、起電力Vと電流Iを乗じて求められる。
   V=S×ΔT                  (数2)
   P=S×ΔT×I                (数3)
なお、(数3)は、熱電変換モジュール内部に、抵抗が無い場合を表わしている。
 (数3)より、熱電変換モジュール内部に抵抗がある場合、実効発電力Peffは、
   Peff=(S×ΔT×I)-(I×R)    (数4)
For example, as shown in (Equation 2) and (Equation 3), the generated power P of the thermoelectric conversion material is obtained by multiplying the electromotive force V and the current I.
V = S × ΔT (Equation 2)
P = S × ΔT × I (Equation 3)
In addition, (Equation 3) represents the case where there is no resistance inside the thermoelectric conversion module.
From (Equation 3), when there is resistance inside the thermoelectric conversion module, the effective power generation Peff is
Peff = (S × ΔT × I) − (I 2 × R) (Equation 4)
で表わされる。(数2)、(数3)および(数4)において、ΔTは接合層/熱電変換素子/接合層間の温度差、Rは内部抵抗を表わす。 It is represented by In (Equation 2), (Equation 3), and (Equation 4), ΔT represents the temperature difference between the junction layer / thermoelectric conversion element / junction layer, and R represents the internal resistance.
 (数4)より、内部抵抗Rが小さい方が、実効発電力Peffが大きくなることが分かる。また、I=S・ΔT/2・Rの時、実効発電力Peffが最大値を取る(数5)ことが分かる。
   Peff・max=(S・ΔT)/4R     (数5)
From (Equation 4), it can be seen that the smaller the internal resistance R, the greater the effective power Peff. It can also be seen that when I = S · ΔT / 2 · R, the effective power generation Peff takes the maximum value (Equation 5).
Peff · max = (S · ΔT) 2 / 4R (Equation 5)
 (数4)および(数5)より、接合層を減らすこと、および接合層の厚さを薄くして内部抵抗Rを小さくすることは、発電力Pの向上に有効であることが分かる。 From (Equation 4) and (Equation 5), it can be seen that reducing the bonding layer and reducing the thickness of the bonding layer to reduce the internal resistance R are effective in improving the power generation P.
 なお、[熱電変換モジュールの性能向上]では、熱電変換素子の両面に接合層を有する熱電変換モジュールの構造を想定して説明した。
 [熱電変換モジュールの製造方法]
In the description of [Improvement of performance of thermoelectric conversion module], the structure of a thermoelectric conversion module having bonding layers on both sides of the thermoelectric conversion element has been described.
[Method of manufacturing thermoelectric conversion module]
 本実施例による熱電変換モジュールの製造方法を、図2~図6を用いて説明する。図2~図6は、本実施例による熱電変換モジュールの製造工程を説明する要部断面図である。 The manufacturing method of the thermoelectric conversion module according to the present embodiment will be described with reference to FIGS. 2 to 6 are cross-sectional views of relevant parts for explaining the manufacturing process of the thermoelectric conversion module according to the present embodiment.
 まず、図2に示すように、高温側電極金属膜23が形成された高温側基板21上に、例えば樹脂からなるマスクパターン61を形成し、エアロゾルデポジション法を用いて高温側電極金属膜23上にP型熱電変換素子膜51を形成する(高温側素子部HP)。 First, as shown in FIG. 2, a mask pattern 61 made of, for example, a resin is formed on the high temperature side substrate 21 on which the high temperature side electrode metal film 23 is formed, and the high temperature side electrode metal film 23 is formed using an aerosol deposition method. A P-type thermoelectric conversion element film 51 is formed thereon (high temperature side element portion HP).
 同様に、低温側電極金属膜24が形成された低温側基板22上に、例えば樹脂からなるマスクパターン61を形成し、エアロゾルデポジション法を用いて低温側電極金属膜24上にN型熱電変換素子膜52を形成する(低温側素子部LP)。 Similarly, a mask pattern 61 made of, for example, a resin is formed on the low-temperature side substrate 22 on which the low-temperature side electrode metal film 24 is formed, and N-type thermoelectric conversion is performed on the low-temperature side electrode metal film 24 using an aerosol deposition method. An element film 52 is formed (low temperature side element portion LP).
 なお、エアロゾルデポジション条件として、キャリアガスは窒素、ガス流量は12リットル/分、成膜圧力は150Pa~350Pa、成膜温度は室温を例示することができる。P型熱電変換素子膜51およびN型熱電変換素子膜52の膜厚は、10μm~1,000μmの範囲である。 As the aerosol deposition conditions, the carrier gas is nitrogen, the gas flow rate is 12 liters / minute, the deposition pressure is 150 Pa to 350 Pa, and the deposition temperature is room temperature. The film thickness of the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 is in the range of 10 μm to 1,000 μm.
 ここで、高温側電極金属膜23上にはP型熱電変換素子膜51のみが直接接合され、低温側電極金属膜24上にはN型熱電変換素子膜52のみが直接接合される。 Here, only the P-type thermoelectric conversion element film 51 is directly bonded on the high-temperature side electrode metal film 23, and only the N-type thermoelectric conversion element film 52 is directly bonded on the low-temperature side electrode metal film 24.
 従って、高温側電極金属膜23上にP型熱電変換素子膜51とN型熱電変換素子膜52の両方を接合した場合、または低温側電極金属膜24上にP型熱電変換素子膜51とN型熱電変換素子膜52の両方を接合した場合と比較すると、高温側基板21および低温側基板22の反りが低減する。 Accordingly, when both the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are bonded on the high-temperature side electrode metal film 23, or the P-type thermoelectric conversion element film 51 and the N-type on the low-temperature side electrode metal film 24. Compared with the case where both of the thermoelectric conversion element films 52 are bonded, warpage of the high temperature side substrate 21 and the low temperature side substrate 22 is reduced.
 これにより、P型熱電変換素子膜51およびN型熱電変換素子膜52の内部応力に起因する高温側基板21および低温側基板22の反りを低減することができる。 Thereby, warpage of the high temperature side substrate 21 and the low temperature side substrate 22 due to internal stress of the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 can be reduced.
 次に、図3に示すように、エアロゾルデポジション法を用いてP型熱電変換素子膜51上およびN型熱電変換素子膜52上に、それぞれ接合材31を形成する。接合材31は、錫-銀-銅はんだからなる。その後、マスクパターン61を除去する。接合材31は、接合材として機能するのであれば他の組成からなるはんだ等の接合材であってもよい。 Next, as shown in FIG. 3, the bonding material 31 is formed on the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52, respectively, using an aerosol deposition method. The bonding material 31 is made of tin-silver-copper solder. Thereafter, the mask pattern 61 is removed. The bonding material 31 may be a bonding material such as solder having another composition as long as it functions as a bonding material.
 次に、図4に示すように、N型熱電変換素子膜52を有する面を上に向けて、N型熱電変換素子膜52等を有する低温側基板22を支持冶具43上に設置する。 Next, as shown in FIG. 4, the low temperature side substrate 22 having the N-type thermoelectric conversion element film 52 and the like is placed on the support jig 43 with the surface having the N-type thermoelectric conversion element film 52 facing upward.
 さらに、P型熱電変換素子膜51を有する面を下に向けて、P型熱電変換素子膜51上の接合材31と低温側電極金属膜24とが接触し、N型熱電変換素子膜52上の接続材31と高温側電極金属膜23とが接触するように、P型熱電変換素子膜51等を有する高温側基板21を、N型熱電変換素子膜52等を有する低温側基板22上に設置する。 Further, with the surface having the P-type thermoelectric conversion element film 51 facing down, the bonding material 31 on the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 are in contact with each other, and the N-type thermoelectric conversion element film 52 is The high temperature side substrate 21 having the P-type thermoelectric conversion element film 51 and the like is placed on the low temperature side substrate 22 having the N type thermoelectric conversion element film 52 and the like so that the connecting material 31 and the high temperature side electrode metal film 23 are in contact with each other. Install.
 次に、図5に示すように、上方から加圧治具44により加圧を行うと共に、加熱を行い、高温側電極金属膜23とN型熱電変換素子膜52、および低圧側電極金属膜24とP型熱電変換素子膜51とをそれぞれ接合材31を介して一括接合させる。 Next, as shown in FIG. 5, pressurization is performed from above by the pressurizing jig 44 and heating is performed, and the high-temperature side electrode metal film 23, the N-type thermoelectric conversion element film 52, and the low-voltage side electrode metal film 24. And the P-type thermoelectric conversion element film 51 are collectively bonded through the bonding material 31.
 接合条件として、接合温度は250℃、加圧は0.5KPaを例示することができる。接合雰囲気は、非酸化性雰囲気であればよく、真空雰囲気、窒素雰囲気または窒素水素混合雰囲気等を用いることができる。 As the joining conditions, the joining temperature can be exemplified by 250 ° C. and the pressurization can be exemplified by 0.5 KPa. The bonding atmosphere may be a non-oxidizing atmosphere, and a vacuum atmosphere, a nitrogen atmosphere, a nitrogen-hydrogen mixed atmosphere, or the like can be used.
 接合温度は、チャンバ内の気圧との関係で変化するものであるが、接合材料が溶融する温度であればよく、できるだけ低い温度であることが望ましい。ここで、チャンバとは、接合材料と被接合部材とを接合させる際に用いる炉であり、窒素を充填して使用する。窒素の充填によって接合材料等の酸化を防ぎ、加熱することによって溶融した接合材料と被接合部材とを接合する。なお、充填される気体は窒素でなくても、接合材料の酸化を防ぐことができれば他の気体でもよい。 The bonding temperature varies depending on the atmospheric pressure in the chamber, but may be a temperature at which the bonding material melts, and is desirably as low as possible. Here, the chamber is a furnace used when the bonding material and the member to be bonded are bonded, and is filled with nitrogen. Oxidation of the bonding material or the like is prevented by filling with nitrogen, and the molten bonding material and the member to be bonded are bonded by heating. Note that the gas to be filled may not be nitrogen, but may be another gas as long as oxidation of the bonding material can be prevented.
 また、接合材31に拡散接合ができる部材を用いる場合は、単に部材の溶融温度である必要はなく、拡散接合される温度以上であればよい。 In addition, when a member capable of diffusion bonding is used as the bonding material 31, it is not necessarily just the melting temperature of the member, and may be higher than the temperature at which diffusion bonding is performed.
 次に、図6に示すように、接合材31は、接合中に高温側電極金属膜23とN型熱電変換素子膜52の成分との拡散反応、および低圧側電極金属膜24とP型熱電変換素子膜51の成分との拡散反応が生じることにより、接合層32となる。 Next, as shown in FIG. 6, the bonding material 31 includes a diffusion reaction between the high-temperature side electrode metal film 23 and the N-type thermoelectric conversion element film 52 during bonding, and the low-voltage side electrode metal film 24 and the P-type thermoelectric. The bonding layer 32 is formed by a diffusion reaction with the components of the conversion element film 51.
 このように、本実施例によれば、高温側電極金属膜23上にP型熱電変換素子膜51のみが形成された高温側基板21と、低温側電極金属膜24上にN型熱電変換素子膜52のみが形成された低温側基板22とが一括接合されることにより、P型熱電変換素子膜51およびN型熱電変換素子膜52の内部応力等に起因した高温側基板21および低温側基板22の反りの低減を図ることができる。 Thus, according to the present embodiment, the high temperature side substrate 21 in which only the P type thermoelectric conversion element film 51 is formed on the high temperature side electrode metal film 23 and the N type thermoelectric conversion element on the low temperature side electrode metal film 24. The high temperature side substrate 21 and the low temperature side substrate caused by the internal stress of the P-type thermoelectric conversion element film 51 and the N-type thermoelectric conversion element film 52 are collectively bonded to the low temperature side substrate 22 on which only the film 52 is formed. 22 warpage can be reduced.
 つまり、接合回数は1度でよいため、高温に晒される回数を少なくすることができる。さらに、接合材は熱電素子に対して一方だけに配置されるため、加圧する力も少なくなる。つまり、接合時に熱電素子が壊れにくくなる。 That is, since the number of times of joining may be one, the number of times of exposure to high temperature can be reduced. Furthermore, since the bonding material is disposed only on one side with respect to the thermoelectric element, the pressure applied is reduced. That is, the thermoelectric element is hardly broken at the time of joining.
 また、高温側電極金属膜23上にはP型熱電変換素子膜51のみを形成し、低温側電極金属膜24上にはN型熱電変換素子膜52のみを形成するので、P型熱電変換素子膜51およびN型熱電変換素子膜52の並べ間違いまたは位置ズレを回避することができるので、熱電変換モジュールの製造歩留りが向上する。 Further, since only the P-type thermoelectric conversion element film 51 is formed on the high-temperature side electrode metal film 23 and only the N-type thermoelectric conversion element film 52 is formed on the low-temperature side electrode metal film 24, the P-type thermoelectric conversion element Since misalignment or misalignment of the film 51 and the N-type thermoelectric conversion element film 52 can be avoided, the manufacturing yield of the thermoelectric conversion module is improved.
 また、P型熱電変換素子膜51の一方の接合面のみを接合層32を介して低温側電極金属膜24と接合し、N型熱電変換素子膜52の一方の接合面のみを接合層32を介して高温側電極金属膜23と接合するので、接合層32の製造に用いる接合材の使用量が減り、熱電変換モジュールの低コスト化が可能となる。 Further, only one bonding surface of the P-type thermoelectric conversion element film 51 is bonded to the low temperature side electrode metal film 24 via the bonding layer 32, and only one bonding surface of the N-type thermoelectric conversion element film 52 is bonded to the bonding layer 32. Therefore, the amount of the bonding material used for manufacturing the bonding layer 32 is reduced, and the cost of the thermoelectric conversion module can be reduced.
 なお、本実施例による熱電変換モジュールにおいて、高温側基板21および低温側基板22に、例えばポリイミド等の樹脂を用い、接合層32に錫-銀-銅はんだを用いた場合は、高温側は200℃程度までの低温度域での使用に限定される。これは、錫-銀-銅はんだの溶融温度による。ポリイミドは300℃程度までの温度で使用できるため、接合材が200℃よりも高い温度で溶融しないものを採用することで、300℃程度で本発明を実施することができる。
 [熱電変換モジュールの出力]
In the thermoelectric conversion module according to the present embodiment, when a resin such as polyimide is used for the high temperature side substrate 21 and the low temperature side substrate 22 and tin-silver-copper solder is used for the bonding layer 32, the high temperature side is 200. It is limited to use in a low temperature range up to about ° C. This depends on the melting temperature of the tin-silver-copper solder. Since polyimide can be used at a temperature up to about 300 ° C., the present invention can be carried out at about 300 ° C. by using a material whose bonding material does not melt at a temperature higher than 200 ° C.
[Output of thermoelectric conversion module]
 本実施例による熱電変換モジュールの出力と、本発明者らが比較例として検討した、熱電変換素子の両面に接合層を有する熱電変換モジュールの出力とを比較した結果を以下に説明する。本発明者らが比較例として検討した熱電変換モジュールの構成を図7に示す。比較例による熱電変換モジュールを構成するP型熱電変換素子53およびN型熱電変換素子54は、熱電変換材料を焼結することにより製作している。 The results of comparing the output of the thermoelectric conversion module according to the present example and the output of the thermoelectric conversion module having the bonding layers on both sides of the thermoelectric conversion element, which the present inventors examined as a comparative example, will be described below. A configuration of a thermoelectric conversion module examined by the present inventors as a comparative example is shown in FIG. The P-type thermoelectric conversion element 53 and the N-type thermoelectric conversion element 54 constituting the thermoelectric conversion module according to the comparative example are manufactured by sintering a thermoelectric conversion material.
 熱電変換材料は、鉄-バナジウム-アルミニウムとし、断面積1.0×10-6、厚さ25×10-6m、熱伝導率4.5W/m・K、導電率1×10-5Ω・mとした。また、接合材は、錫-銀-銅はんだとし、断面積1.0×10-6、厚さ5×10-6m~25×10-6m、熱伝導率55.0W/m・K、導電率11×10-8Ω・mとした。 The thermoelectric conversion material is iron-vanadium-aluminum, the cross-sectional area is 1.0 × 10 −6 m 2 , the thickness is 25 × 10 −6 m, the thermal conductivity is 4.5 W / m · K, and the electrical conductivity is 1 × 10 −. 5 Ω · m. The bonding material is tin-silver-copper solder, the cross-sectional area is 1.0 × 10 −6 m 2 , the thickness is 5 × 10 −6 m to 25 × 10 −6 m, and the thermal conductivity is 55.0 W / m. K, conductivity 11 × 10 −8 Ω · m
 (数6)に示すように、接合材熱抵抗は、接合材断面積を一定と仮定すると、接合材厚さに比例することが分かる。また、電気抵抗も、厚さ(長さ)が大きくなると増大することから、本実施例では、接合材厚さを変動させて説明する。
   Rth=1/λc・t/A            (数6)
As shown in (Equation 6), it can be seen that the bonding material thermal resistance is proportional to the bonding material thickness, assuming that the bonding material cross-sectional area is constant. In addition, since the electrical resistance increases as the thickness (length) increases, this embodiment will be described by varying the thickness of the bonding material.
Rth = 1 / λc · t / A (Equation 6)
(数6)において、Rthは接合材熱抵抗、λcは接合材熱伝導率、Aは接合材断面積、tは接合材厚さを表わす。 In (Expression 6), Rth represents the bonding material thermal resistance, λc represents the bonding material thermal conductivity, A represents the bonding material cross-sectional area, and t represents the bonding material thickness.
 一般に、出力電力は、接合材を有する熱電変換素子の出力電力を熱電変換素子単体の出力電力で除した値である出力電力比で表わす。
 熱電変換素子単体の出力Piを(数7)に示す。
   Pi=S/ρ(A/l)(ΔT/4)    (数7)
In general, the output power is represented by an output power ratio that is a value obtained by dividing the output power of the thermoelectric conversion element having the bonding material by the output power of the thermoelectric conversion element alone.
The output Pi of the single thermoelectric conversion element is shown in (Expression 7).
Pi = S 2 / ρ (A / l 0) (ΔT 2/4) ( 7)
出力Piは、接触抵抗を含まない。なお、(数7)は、前述の(数5)より導かれる。(数7)において、Sはゼーベック係数、ρは素子電気抵抗率、Aは素子断面積、lは素子厚さ、ΔTは単体素子の両端温度差を表わす。 The output Pi does not include contact resistance. (Equation 7) is derived from the above (Equation 5). In (Expression 7), S is the Seebeck coefficient, ρ is the element electrical resistivity, A is the element cross-sectional area, 10 is the element thickness, and ΔT is the temperature difference between both ends of the single element.
 (数7)より、熱電変換素子の最大出力は、ゼーベック係数Sの2乗に比例し、かつ熱電変換素子の両端部に印加される温度差ΔTが、素子出力を決定する最大要因であることが分かる。
 次に、接触抵抗(接合材)を有する熱電変換素子の出力Pcを(数8)に示す。
From (Equation 7), the maximum output of the thermoelectric conversion element is proportional to the square of the Seebeck coefficient S, and the temperature difference ΔT applied to both ends of the thermoelectric conversion element is the maximum factor that determines the element output. I understand.
Next, the output Pc of the thermoelectric conversion element having contact resistance (bonding material) is shown in (Equation 8).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
(数8)において、ρは素子電気抵抗率、ρcは接合材電気抵抗率、lは素子厚さ、lcは接合材厚さ、λは素子熱伝導率、λcは接合材熱伝導率を表わす。 In (Equation 8), ρ is the element electric resistivity, ρc is the bonding material electric resistivity, 10 is the element thickness, lc is the bonding material thickness, λ is the element thermal conductivity, and λc is the bonding material thermal conductivity. Represent.
 出力Pcは、出力Piが接触抵抗および熱抵抗を含む状態を示しており、接合材による抵抗増加分の比で導出している。分母の右項は、接合材の熱抵抗によって、出力Piの素子単体よりも付与できる温度(温度付与率σ)が小さくなることを熱伝導率比で表わしている。なお、σ={接続材熱抵抗による熱損失を被った高温部温度θh-接続材熱抵抗による熱損失を被った低温部温度θc}/{素子単体での高温部温度(Th)-素子単体での低温部温度(Tc)}=Δθ/ΔTである。 The output Pc indicates a state in which the output Pi includes contact resistance and thermal resistance, and is derived by the ratio of the resistance increase due to the bonding material. The right term of the denominator represents the thermal conductivity ratio that the temperature (temperature application rate σ) that can be applied is smaller than the element of the output Pi due to the thermal resistance of the bonding material. Note that σ = {the high temperature part temperature θh that suffered heat loss due to the connecting material thermal resistance−the low temperature part temperature θc that suffered the heat loss caused by the connecting material thermal resistance} / {the high temperature part temperature of the element alone (Th) −the element alone At low temperature (Tc)} = Δθ / ΔT.
 (数8)は、熱電変換素子の両面に接合材を有する比較例による熱電変換モジュールでの出力を導出する。 (Equation 8) derives the output of the thermoelectric conversion module according to the comparative example having the bonding material on both surfaces of the thermoelectric conversion element.
 熱電変換素子の片面に接合材を有する本実施例による熱電変換モジュールの出力計算を、(数9)に示す。 (Equation 9) shows the output calculation of the thermoelectric conversion module according to the present example having the bonding material on one side of the thermoelectric conversion element.
Figure JPOXMLDOC01-appb-M000002

(数8)および(数9)を用いて、出力電力比を導出した。
Figure JPOXMLDOC01-appb-M000002

Using (Equation 8) and (Equation 9), the output power ratio was derived.
 図8は、本実施例による熱電変換モジュールおよび比較例による熱電変換モジュールの出力電力比を示すグラフ図である。図8の縦軸は出力電力比を、横軸は接合材の厚さを表わしている。 FIG. 8 is a graph showing the output power ratio of the thermoelectric conversion module according to the present embodiment and the thermoelectric conversion module according to the comparative example. The vertical axis in FIG. 8 represents the output power ratio, and the horizontal axis represents the thickness of the bonding material.
 図8に示すように、本実施例による熱電変換モジュールは、比較例による熱電変換モジュールと比較して、接合材厚さが0.005mmの場合、出力を3.2%向上することができ、接合材厚さが0.015mmの場合、出力を8.4%向上することができる。 As shown in FIG. 8, the thermoelectric conversion module according to this example can improve the output by 3.2% when the bonding material thickness is 0.005 mm, compared with the thermoelectric conversion module according to the comparative example. When the bonding material thickness is 0.015 mm, the output can be improved by 8.4%.
 このように、熱電変換素子の片面に接合材を有する本実施例による熱電変換モジュールは、熱電変換素子の両面に接合材を有する比較例による熱電変換モジュールよりも発電力を向上することができる。 Thus, the thermoelectric conversion module according to the present embodiment having the bonding material on one side of the thermoelectric conversion element can improve the power generation as compared with the thermoelectric conversion module according to the comparative example having the bonding material on both sides of the thermoelectric conversion element.
 なお、本実施例は、熱電変換素子および接合層の構成についての一例を示すものであり、ここに例示する構成のみに限定されるものではない。以下に、種々の変形例について説明する。
 (変形例1)
In addition, a present Example shows an example about the structure of a thermoelectric conversion element and a joining layer, and is not limited only to the structure illustrated here. Hereinafter, various modifications will be described.
(Modification 1)
 変形例1による熱電変換モジュールを、図9を用いて以下に説明する。図9は、変形例1による熱電変換モジュールの素子近傍を示す要部側面図である。 The thermoelectric conversion module according to Modification 1 will be described below with reference to FIG. FIG. 9 is a main part side view showing the vicinity of the elements of the thermoelectric conversion module according to the first modification.
 変形例1による熱電変換モジュールと、前述した図1に示す熱電変換モジュールとの相違点は、P型熱電変換素子膜51と低温側電極金属膜24とを接続する接続部分の構造およびN型熱電変換素子膜52と高温側電極金属膜23とを接続する接続部分の構造である。 The difference between the thermoelectric conversion module according to the modified example 1 and the thermoelectric conversion module shown in FIG. 1 described above is that the structure of the connecting portion connecting the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 and the N-type thermoelectric. This is a structure of a connection portion for connecting the conversion element film 52 and the high temperature side electrode metal film 23.
 前述した図1に示す熱電変換モジュールでは、上記接続部分は、接合層32により構成されている。これに対して、変形例1による熱電変換モジュールでは、上記接続部分は、接合材31と接合層32とからなり、一部に接合材31を残している。 In the thermoelectric conversion module shown in FIG. 1 described above, the connecting portion is constituted by a bonding layer 32. On the other hand, in the thermoelectric conversion module according to the modified example 1, the connecting portion includes the bonding material 31 and the bonding layer 32, and the bonding material 31 is left in a part.
 前述した図1に示す熱電変換モジュールでは、支持治具43と加圧治具44とを用いて加圧および加熱を行い、接合材31を全て接合層32に変えたが、一部に接合材31が残っていてもよい。この場合も、前述した図1に示す熱電変換モジュールとほぼ同様の効果が得られる。
 (変形例2)
In the thermoelectric conversion module shown in FIG. 1 described above, pressurization and heating are performed using the support jig 43 and the pressurization jig 44, and the bonding material 31 is entirely changed to the bonding layer 32. 31 may remain. Also in this case, substantially the same effect as the thermoelectric conversion module shown in FIG. 1 described above can be obtained.
(Modification 2)
 変形例2による熱電変換モジュールを、図10を用いて以下に説明する。図10は、変形例2による熱電変換モジュールの素子近傍を示す要部側面図である。 The thermoelectric conversion module according to Modification 2 will be described below with reference to FIG. FIG. 10 is a main part side view showing the vicinity of the elements of the thermoelectric conversion module according to the second modification.
 変形例2による熱電変換モジュールと、前述した図1に示す熱電変換モジュールとの相違点は、P型熱電変換素子膜51と低温側電極金属膜24とを接続する接続部分の構造およびN型熱電変換素子膜52と高温側電極金属膜23とを接続する接続部分の構造である。 The difference between the thermoelectric conversion module according to the modified example 2 and the thermoelectric conversion module shown in FIG. 1 described above is that the structure of the connecting portion connecting the P-type thermoelectric conversion element film 51 and the low-temperature side electrode metal film 24 and the N-type thermoelectric. This is a structure of a connection portion for connecting the conversion element film 52 and the high temperature side electrode metal film 23.
 前述した図1に示す熱電変換モジュールでは、上記接続部分は、接合層32により構成されている。これに対して、変形例2による熱電変換モジュールでは、上記接続部分は、金属層33と接合層32との積層からなる。すなわち、接合層32とP型熱電変換素子膜51との間および接合層32とN型熱電変換素子膜52との間に金属層33が形成されている。金属層33は、例えばチタン、ニッケル、クロムまたはコバルトからなる金属層、あるいはこれらの金属のうちのいずれかを主成分とする金属層である。ここで主成分とは、複数の元素を含有する部材において、含有率が一番多い成分をいう。 In the thermoelectric conversion module shown in FIG. 1 described above, the connecting portion is constituted by a bonding layer 32. On the other hand, in the thermoelectric conversion module according to the second modification, the connection portion is formed by stacking the metal layer 33 and the bonding layer 32. That is, the metal layer 33 is formed between the bonding layer 32 and the P-type thermoelectric conversion element film 51 and between the bonding layer 32 and the N-type thermoelectric conversion element film 52. The metal layer 33 is a metal layer made of, for example, titanium, nickel, chromium, or cobalt, or a metal layer mainly composed of any one of these metals. Here, the main component refers to a component having the highest content rate in a member containing a plurality of elements.
 金属膜33は、接合層32を構成する元素のP型熱電変換素子膜51またはN型熱電変換素子膜52への拡散を防止する機能を有する。このように、拡散防止膜として機能する金属層33を、接合層32と積層して形成することにより、P型熱電変換素子膜51またはN型熱電変換素子膜52への不純物元素のドーピングを抑制することができるので、P型熱電変換素子膜51またはN型熱電変換素子膜52の熱電性能の劣化による熱電モジュールの熱電特性(起電力)の低下を防止することができる。
 (変形例3)
 変形例3による熱電変換モジュールを以下に説明する。
The metal film 33 has a function of preventing diffusion of elements constituting the bonding layer 32 into the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52. As described above, the metal layer 33 functioning as a diffusion prevention film is formed so as to be laminated with the bonding layer 32, thereby suppressing doping of the impurity element into the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52. Therefore, it is possible to prevent a decrease in thermoelectric characteristics (electromotive force) of the thermoelectric module due to deterioration of the thermoelectric performance of the P-type thermoelectric conversion element film 51 or the N-type thermoelectric conversion element film 52.
(Modification 3)
A thermoelectric conversion module according to Modification 3 will be described below.
 変形例3による熱電変換モジュールと、前述した図1に示す熱電変換モジュールとの相違点は、高温側基板21および低温側基板22の材質、並びに接合層32の材質である。 The difference between the thermoelectric conversion module according to the modification 3 and the thermoelectric conversion module shown in FIG. 1 described above is the material of the high temperature side substrate 21 and the low temperature side substrate 22 and the material of the bonding layer 32.
 すなわち、前述した図1に示す熱電変換モジュールでは、高温側基板21および低温側基板22に、例えばポリイミド等の樹脂を用い、接合層32に錫-銀-銅はんだを用いた。これに対して、変形例3による熱電変換モジュールでは、高温側基板21および低温側基板22に、例えばアルミナ等のセラミックスを用い、接合層32に銅を用いる。 That is, in the thermoelectric conversion module shown in FIG. 1 described above, a resin such as polyimide is used for the high temperature side substrate 21 and the low temperature side substrate 22, and tin-silver-copper solder is used for the bonding layer 32. On the other hand, in the thermoelectric conversion module according to the modified example 3, ceramics such as alumina is used for the high temperature side substrate 21 and the low temperature side substrate 22, and copper is used for the bonding layer 32.
 セラミックスの厚さは、例えば0.3mm程度である。高温側基板21および低温側基板22にセラミックスを用いることにより、300℃~600℃程度の中・高温域にも熱電変換モジュールを使用することができる。 The thickness of the ceramic is, for example, about 0.3 mm. By using ceramics for the high temperature side substrate 21 and the low temperature side substrate 22, the thermoelectric conversion module can be used even in the middle / high temperature range of about 300 ° C. to 600 ° C.
 P型熱電変換素子51およびN型熱電変換素子52の接合面に、厚さ5.0μm程度の銅を形成し、高温側電極金属膜23および低温側電極金属膜24を構成する銅と常温接合、超音波接合または拡散接合させることにより、極薄の接合層32を形成することができる。これにより、変形例3による熱電変換モジュールは、前述した図1に示す熱電変換モジュールよりも発電力を向上することができる。また、銅の融点が1,085℃と高いので、300℃~600℃程度の中・高温域にも熱電変換モジュールを使用することができる。 Copper having a thickness of about 5.0 μm is formed on the bonding surface of the P-type thermoelectric conversion element 51 and the N-type thermoelectric conversion element 52, and room temperature bonding with copper constituting the high temperature side electrode metal film 23 and the low temperature side electrode metal film 24. The ultrathin bonding layer 32 can be formed by ultrasonic bonding or diffusion bonding. Thereby, the thermoelectric conversion module by the modification 3 can improve electric power generation rather than the thermoelectric conversion module shown in FIG. 1 mentioned above. Further, since the melting point of copper is as high as 1,085 ° C., the thermoelectric conversion module can be used also in the middle / high temperature range of about 300 ° C. to 600 ° C.
 このように、変形例3によれば、200℃~600℃程度の低・中・高温域で使用できる熱電変換モジュールを提供することができる。 Thus, according to Modification 3, it is possible to provide a thermoelectric conversion module that can be used in a low, medium, and high temperature range of about 200 ° C. to 600 ° C.
 以上、本発明者によってなされた発明を実施の形態に基づき具体的に説明したが、本発明は前記実施の形態に限定されるものではなく、その要旨を逸脱しない範囲で種々変更可能であることはいうまでもない。 As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.
  1 熱電変換モジュール素子組立体
 21 高温側基板
 22 低温側基板
 23 高温側電極金属膜
 24 低温側電極金属膜
 31 接合材
 32 接合層
 33 金属層
 43 支持治具
 44 加圧治具
 51 P型熱電変換素子膜
 52 N型熱電変換素子膜
 53 P型熱電変換素子
 54 N型熱電変換素子
 61 マスクパターン
 HP 高温側素子部
 LP 低温側素子部
DESCRIPTION OF SYMBOLS 1 Thermoelectric conversion module element assembly 21 High temperature side board | substrate 22 Low temperature side board | substrate 23 High temperature side electrode metal film 24 Low temperature side electrode metal film 31 Joining material 32 Joining layer 33 Metal layer 43 Support jig 44 Pressure jig 51 P-type thermoelectric conversion Element film 52 N type thermoelectric conversion element film 53 P type thermoelectric conversion element 54 N type thermoelectric conversion element 61 Mask pattern HP High temperature side element part LP Low temperature side element part

Claims (14)

  1.  第1の面と、前記第1の面と反対側の第2の面とを有する第1の熱電変換素子膜と、
     前記第1の面と同じ方向を向く第3の面と、前記第3の面と反対側の第4の面とを有する第2の熱電変換素子膜と、
     前記第1の面に接合層を介して接合され、かつ前記第3の面に直接接合された第1の電極と、
     前記第2の面に直接接合された第2の電極と、
     前記第4の面に接合層を介して接合された第3の電極と、
    を有し、
     前記第1の熱電変換素子膜と前記第2の熱電変換素子膜とが直列に接続されている、熱電変換モジュール。
    A first thermoelectric conversion element film having a first surface and a second surface opposite to the first surface;
    A second thermoelectric conversion element film having a third surface facing the same direction as the first surface and a fourth surface opposite to the third surface;
    A first electrode bonded to the first surface via a bonding layer and directly bonded to the third surface;
    A second electrode directly bonded to the second surface;
    A third electrode bonded to the fourth surface via a bonding layer;
    Have
    A thermoelectric conversion module in which the first thermoelectric conversion element film and the second thermoelectric conversion element film are connected in series.
  2.  請求項1記載の熱電変換モジュールにおいて、
     前記第1の熱電変換素子膜および前記第2の熱電変換素子膜の厚さは、10μm以上、かつ1,000μm以下である、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    The thermoelectric conversion module, wherein a thickness of the first thermoelectric conversion element film and the second thermoelectric conversion element film is 10 μm or more and 1,000 μm or less.
  3.  請求項1記載の熱電変換モジュールにおいて、
     前記接合層の厚さは、5.0μm以上、かつ20.0μm以下である、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    The thermoelectric conversion module, wherein the bonding layer has a thickness of 5.0 μm or more and 20.0 μm or less.
  4.  請求項1記載の熱電変換モジュールにおいて、
     前記第1の電極、前記第2の電極および前記第3の電極の厚さは、1.0μm以上、かつ0.5mm以下である、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    The thermoelectric conversion module, wherein the first electrode, the second electrode, and the third electrode have a thickness of 1.0 μm or more and 0.5 mm or less.
  5.  請求項1記載の熱電変換モジュールにおいて、
     前記接合層と前記第1の熱電変換素子膜または前記第2の熱電変換素子膜との間に、拡散防止膜が形成されている、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    A thermoelectric conversion module, wherein a diffusion prevention film is formed between the bonding layer and the first thermoelectric conversion element film or the second thermoelectric conversion element film.
  6.  請求項1記載の熱電変換モジュールにおいて、
     前記接合層は、錫-銀-銅はんだからなり、前記第1の電極、前記第2の電極および前記第3の電極は、銅からなる、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    The thermoelectric conversion module, wherein the bonding layer is made of tin-silver-copper solder, and the first electrode, the second electrode, and the third electrode are made of copper.
  7.  請求項1記載の熱電変換モジュールにおいて、
     前記接合層、前記第1の電極、前記第2の電極および前記第3の電極は、銅からなる、熱電変換モジュール。
    The thermoelectric conversion module according to claim 1,
    The thermoelectric conversion module, wherein the bonding layer, the first electrode, the second electrode, and the third electrode are made of copper.
  8.  以下の工程を含む熱電変換モジュールの製造方法:
     (a)複数の第1の電極のそれぞれの第1の領域上に、第1の熱電変換素子膜を形成する工程;
     (b)前記第1の熱電変換素子膜の上面上に第1の接合材を形成する工程;
     (c)複数の第2の電極のそれぞれの第2の領域上に、第2の熱電変換素子膜を形成する工程;
     (d)前記第2の熱電変換素子膜の上面上に第2の接合材を形成する工程;
     (e)前記第1の電極の前記第1の熱電変換素子膜が形成された面と、前記第2の電極の前記第2の熱電変換素子膜が形成された面とを対向させ、
     前記第2の接合材を介して、複数の前記第1電極のそれぞれの前記第1の領域に隣接する第3の領域上に前記第2の熱電変換素子膜を接合し、前記第1接合材を介して、複数の前記第2電極のそれぞれの前記第2の領域に隣接する第4の領域上に前記第1の熱電変換素子膜を接合する工程;
     (f)前記(e)工程の後、前記第1の電極と前記第2の電極との間を加圧および加熱する工程。
    A method for producing a thermoelectric conversion module including the following steps:
    (A) forming a first thermoelectric conversion element film on each first region of the plurality of first electrodes;
    (B) forming a first bonding material on the upper surface of the first thermoelectric conversion element film;
    (C) forming a second thermoelectric conversion element film on each second region of the plurality of second electrodes;
    (D) forming a second bonding material on the upper surface of the second thermoelectric conversion element film;
    (E) The surface of the first electrode on which the first thermoelectric conversion element film is formed is opposed to the surface of the second electrode on which the second thermoelectric conversion element film is formed,
    The second thermoelectric conversion element film is bonded onto the third region adjacent to the first region of each of the plurality of first electrodes via the second bonding material, and the first bonding material Bonding the first thermoelectric conversion element film on a fourth region adjacent to the second region of each of the plurality of second electrodes via
    (F) A step of pressurizing and heating between the first electrode and the second electrode after the step (e).
  9.  請求項8記載の熱電変換モジュールの製造方法において、
     前記第1の熱電変換素子膜および前記第2の熱電変換素子膜は、蒸着法、スパッタリング法、エアロゾルデポジション法または印刷法により形成される、熱電変換モジュール。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The first thermoelectric conversion element film and the second thermoelectric conversion element film are formed by a vapor deposition method, a sputtering method, an aerosol deposition method, or a printing method.
  10.  請求項8記載の熱電変換モジュールの製造方法において、
     前記第1の熱電変換素子膜および前記第2の熱電変換素子膜の厚さは、10μm以上、かつ1,000μm以下である、熱電変換モジュールの製造方法。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The manufacturing method of the thermoelectric conversion module whose thickness of the said 1st thermoelectric conversion element film | membrane and the said 2nd thermoelectric conversion element film | membrane is 10 micrometers or more and 1,000 micrometers or less.
  11.  請求項8記載の熱電変換モジュールの製造方法において、
     前記接合層の厚さは、5.0μm以上、かつ20.0μm以下である、熱電変換モジュールの製造方法。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The thickness of the said joining layer is a manufacturing method of the thermoelectric conversion module which is 5.0 micrometers or more and 20.0 micrometers or less.
  12.  請求項8記載の熱電変換モジュールの製造方法において、
     前記第1の接合材および前記第2の接合材は、錫-銀-銅はんだからなり、前記第1の電極および前記第2の電極は銅からなる、熱電変換モジュールの製造方法。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The method for manufacturing a thermoelectric conversion module, wherein the first bonding material and the second bonding material are made of tin-silver-copper solder, and the first electrode and the second electrode are made of copper.
  13.  請求項8記載の熱電変換モジュールの製造方法において、
     前記第1の接合材、前記第2の接合材、前記第1の電極および前記第2の電極は、銅からなり、
     前記(e)工程では、前記第1の接合材と前記第2の電極、および前記第2の接合材と前記第1の電極とを常温接合、超音波接合または拡散接合する、熱電変換モジュールの製造方法。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The first bonding material, the second bonding material, the first electrode, and the second electrode are made of copper,
    In the step (e), a thermoelectric conversion module that performs room temperature bonding, ultrasonic bonding, or diffusion bonding of the first bonding material and the second electrode, and the second bonding material and the first electrode. Production method.
  14.  請求項8記載の熱電変換モジュールの製造方法において、
     前記複数の第1の電極は、第1の基板上に形成され、前記複数の第2の電極は、第2の基板上に形成され、
     前記第1の基板および前記第2の基板は、樹脂またはセラミックスからなる、熱電変換モジュールの製造方法。
    In the manufacturing method of the thermoelectric conversion module of Claim 8,
    The plurality of first electrodes are formed on a first substrate, the plurality of second electrodes are formed on a second substrate,
    The method for manufacturing a thermoelectric conversion module, wherein the first substrate and the second substrate are made of resin or ceramics.
PCT/JP2015/071226 2015-07-27 2015-07-27 Thermoelectric conversion module and method for manufacturing same WO2017017757A1 (en)

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