Patent Application
20230045816
The present invention relates to a thermoelectric conversion structure which includes a thermoelectric conversion element.
In order to effectively utilize heat, a thermoelectric conversion structure, which includes a thermoelectric conversion element of the Seebeck effect and the Peltier effect or the like, is used. For example, Patent Document 1 discloses a thermoelectric conversion system that includes: a thermoelectric conversion element in which a plurality of p-type and n-type semiconductor elements are alternately and electrically connected in series through metal electrodes; and a metal heat exchanger which is in indirect contact with the thermoelectric conversion element, and in the thermoelectric conversion system, an insulating layer formed with a composite film of resin and inorganic powder is integrally adhered to the thermoelectric conversion element or the metal heat exchanger, and the thermoelectric conversion element and the metal heat exchanger are joined together through a thermally conductive grease with the insulating layer arranged therebetween.
[Patent Document 1] JPH11-340523 A
In the thermoelectric conversion structure disclosed in Patent Document 1, the thermally conductive grease layer is formed on the joint surface of constituent members in order to enhance thermal conductivity between the constituent members. However, as the thermoelectric conversion structure of Patent Document 1, the uniform thermally conductive grease layer is formed while air bubbles are prevented from being mixed into the joint surface of the constituent members, and this can also reduce the productivity of the thermoelectric conversion structure. In recent years, an attempt has been made to detachably attach, to an article or part of a human body, a thermoelectric conversion module in which a thermoelectric conversion element is sandwiched between insulators to heat or cool the article or the part of the human body. As described above, when the thermoelectric conversion module is detachably attached to the article or the part of the human body, a thermally conductive grease layer cannot be formed for the purpose of enhancing heat transfer characteristics therebetween, with the result that the heat transfer characteristics therebetween is lowered.
The present invention is made in order to solve the problem described above, and an object of the present invention is to provide a thermoelectric conversion structure in which a thermoelectric conversion module having a thermoelectric conversion element sandwiched between thermally conductive members and heat transfer target members such as a heat dissipation member and a heat absorption member are removable and which can enhance heat transfer characteristics therebetween.
A thermoelectric conversion structure according to the present invention is provided to achieve the object described above. In the thermoelectric conversion structure in which a thermoelectric conversion module integrated by joining surfaces of a thermoelectric conversion element on a high temperature side and a low temperature side to thermally conductive elastomer sheets containing a thermally conductive filler is arranged between heat transfer target members that transfer heat to the thermoelectric conversion element, surfaces of the thermally conductive elastomer sheets and corresponding surfaces of the heat transfer target members are in direct intimate contact with each other.
The hardness of the thermally conductive elastomer sheet measured with a type A durometer according to JIS K 6253 is 90/s or less, and thus intimate contact between the thermally conductive elastomer sheets and the heat transfer target members can be enhanced, and the countermeasure of thermal deformation such as thermal expansion of constituent members can be further enhanced.
The thermal conductivity of the thermally conductive elastomer sheet is 1.0 W/(m·K) or more, and thus it is possible to enhance heat exchange characteristics between the thermoelectric conversion element and the heat transfer target members.
The thermoelectric conversion element and the thermally conductive elastomer sheets are integrally joined by a direct covalent bond between active groups in the surfaces of the thermoelectric conversion element and the thermally conductive elastomer sheets and/or an indirect covalent bond therebetween through a molecular adhesive, and thus even if the constituent members of the thermoelectric conversion structure are thermally deformed by thermal expansion or the like, it is possible to prevent separation between the thermoelectric conversion element and the thermally conductive elastomer sheets.
Since in the thermoelectric conversion structure according to the present invention, the thermoelectric conversion element is arranged between heat transfer target members through thermally conductive elastomer sheets, even if the constituent members are thermally deformed by thermal expansion or the like, the thermal deformation can be absorbed by the thermally conductive elastomer sheets. Moreover, in the thermoelectric conversion module of the thermoelectric conversion structure according to the present invention, the surfaces of the thermoelectric conversion element on a high temperature side and the low temperature side are integrally joined to the thermally conductive elastomer sheets containing the thermally conductive filler, and the surfaces of the thermally conductive elastomer sheets of the thermoelectric conversion module are in direct intimate contact with the corresponding surfaces of the heat transfer target members, with the result that it is possible to provide satisfactory heat transfer characteristics without the formation of a thermally conductive grease layer on the joint surfaces. As described above, the thermoelectric conversion module and the heat transfer target members can be in intimate contact with each other without the formation of the thermally conductive grease layer, and thus the productivity of the thermoelectric conversion structure can be enhanced and the thermoelectric conversion structure can also be used for an application for removing the thermoelectric conversion module from the heat transfer target members and a human body.
Although the present invention will be described in detail below, the scope of the present invention is not limited to the following description.
An example of a thermoelectric conversion structure according to the present invention is shown in
The thermally conductive elastomer sheet 20 is formed of a thermally conductive elastomer containing a thermally conductive filler. Examples of the thermally conductive filler include magnesium oxide (MgO), aluminum oxide (Al2O3), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si3N4), diamond, carbon, fullerene, carbon graphite and combinations of two or more types thereof. The amount of thermally conductive filler mixed is preferably 50 to 95% by weight (and more preferably 65 to 90% by weight).
The components of the thermally conductive elastomer are formed of an elastomer composition including at least a resin material or a rubber material. Examples of the resin material include polyimide, PEEK, PSS and the like. Examples of the rubber material include silicone rubber, ethylene-propylene-diene copolymer rubber (EPDM), urethane rubber, fluororubber and the like. Among these materials, in terms of enhancing flexibility, tackiness and a following capability, silicone rubber is preferable, and in terms of lowering gas permeability and enhancing water resistance, EPDM is preferable.
The main component of the silicone rubber serving as the rubber material is peroxide cross-linking silicone rubber, additional cross-linking silicone rubber, condensation cross-linking silicone rubber or a blend of one of these silicone rubbers and olefin rubber. A heat dissipation rubber insulator formed of silicone rubber is used, and thus high flexibility is provided in a wide temperature range of, for example, −40° C. to 200° C., flexural fatigue resistance and the following capability can be enhanced and expansion caused by a heat shock can be prevented. These silicone rubbers have a number average molecular weight of 10000 to 1 million.
Although the peroxide cross-linking silicone rubber is not particularly limited as long as the peroxide cross-linking silicone rubber is synthesized with a silicone raw material compound capable of being cross-linking by a peroxide cross-linking agent, and specific examples thereof include polydimethylsiloxane, vinylmethylsiloxane/polydimethylsiloxane copolymer, vinyl-terminated polydimethyl siloxane, vinyl-terminated diphenyl siloxane/polydimethyl siloxane copolymer, vinyl-terminated diethyl siloxane/polydimethyl siloxane copolymer, vinyl-terminated trifluoropropylmethyl siloxane/polydimethylsiloxane copolymer, vinyl-terminated polyphenylmethyl siloxane, vinylmethyl siloxane/dimethyl siloxane copolymer, trimethylsiloxane group-terminated dimethylsiloxane/vinylmethylsiloxane copolymer, trimethylsiloxane group-terminated dimethyl siloxane/vinylmethyl siloxane/diphenyl siloxane copolymer, trimethyl siloxane group-terminated dimethyl siloxane/vinylmethylsiloxane/ditrifluoropropylmethyl siloxane copolymer, trimethylsiloxane group-terminated polyvinyl methylsiloxane, metacryloxypropyl group-terminated polydimethylsiloxane, acryloxypropyl group-terminated polydimethylsiloxane, (metacryloxypropyl) methylsiloxane/dimethylsiloxane copolymer, and (acryloxypropyl) methylsiloxane/dimethylsiloxane copolymer.
Examples of the peroxide cross-linking agent which is made to coexist therewith include ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters and percarbonates, and specific examples thereof include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxycarbonate, peroxyester, benzoyl peroxide, dicumyl peroxide, dibenzoyl peroxide, t-butylhydroperoxide, di-t-butylhydroperoxide, di(dicyclobenzoyl) peroxide, 2,5-dimethyl-2,5 bis(t-butylperoxy) hexane, 2,5-dimethyl-2,5 bis(t-butylperoxy) hexine, benzophenone, Michler's ketone, dimethylaminobenzoic acid ethyl ester and benzoin ethyl ether.
Although the amount of the peroxide cross-linking agent used is selected as necessary according to the type of silicone rubber obtained, the properties of the heat dissipation rubber insulator formed of the silicone rubber and the properties of a silane coupling agent used as necessary, the amount of the peroxide cross-linking agent used is 0.01 to 10 parts by mass, and preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of silicone rubber. If the amount of peroxide cross-linking agent used is less than the range described above, the degree of cross-linking is excessively low, and thus the peroxide cross-linking agent cannot be used as silicone rubber. On the other hand, if the amount of peroxide cross-linking agent used is larger than the range described above, the degree of cross-linking is excessively high, and thus the elasticity of the silicone rubber is reduced.
The additional cross-linking silicone rubber is obtained from: a composition of vinyl group-containing polysiloxane such as vinyl methyl siloxane/polydimethyl siloxane copolymer synthesized in the presence of a Pt catalyst, vinyl-terminated polydimethyl siloxane, vinyl-terminated diphenyl siloxane/polydimethyl siloxane copolymer, vinyl-terminated diethyl siloxane/polydimethyl siloxane copolymer, viny-terminated trifluoropropyl methyl siloxane/polydimethylsiloxane copolymer, vinyl-terminated polyphenylmethyl siloxane, vinylmethyl siloxane/dimethyl siloxane copolymer, trimethylsiloxane group-terminated dimethyl siloxane/vinylmethyl siloxane/diphenyl siloxane copolymer, trimethylsiloxane group-terminated dimethylsiloxane/vinylmethyl siloxane/ditrifluoropropylmethyl siloxane copolymer or trimethylsiloxane group-terminated polyvinylmethylsiloxane and of H group-containing polysiloxane exemplified by H-terminated polysiloxane, methyl-H-siloxane/dimethylsiloxane copolymer, polymethyl-H-siloxane, polyethyl-H-siloxane, H-terminated polyphenyl (dimethyl-H-siloxy) siloxane, methyl-H-siloxane/phenylmethyl siloxane copolymer or methyl-H-siloxane/octylmethylsiloxane copolymer; or a composition of amino group-containing polysiloxane exemplified by aminopropyl-terminated polydimethylsiloxane, aminopropylmethylsiloxane/dimethylsiloxane copolymer, aminoethylaminoisobutylmethylsiloxane/dimethylsiloxane copolymer, aminoethylaminopropylmethoxysiloxane/dimethyl siloxane copolymer or dimethylamino-terminated polydimethylsiloxane, and of epoxy group-containing polysiloxane exemplified by epoxypropyl-terminated polydimethylsiloxane or (epoxycyclohexylethyl) methylsiloxane/dimethylsiloxane copolymer, acid anhydride group-containing polysiloxane exemplified by succinic acid anhydride-terminated polydimethylsiloxane and an isocyanate group-containing compound such as toluyl diisocyanate or 1,6-hexamethylene diisocyanate.
When the thermally conductive elastomer is produced from these compositions, the compositions and the thermally conductive filler are kneaded and are thereafter heated at a predetermined temperature for a predetermined time and thus the thermally conductive elastomer can be obtained. Although the production conditions such as the heating temperature and the heating time differ depending on the type and characteristics of an addition reaction, and thus they cannot be uniquely determined, in general, the heating is performed at 0 to 200° C. for one minute to 24 hours. In this way, the additional cross-linking silicone rubber with which the thermally conductive filler is mixed and which has thermal conductivity is obtained. When the physical properties of the silicone rubber are excellent, a reaction time is longer under low temperature processing conditions. When quick productivity is required as compared with the physical properties, the production is performed under the processing conditions of high temperature and short time. When the processing needs to be performed within a certain time depending on a production process and a work environment, the processing temperature is set to a relatively high temperature within the range described above according to a desired processing time, and thus the production is performed.
The condensation cross-linking silicone rubber is obtained from: a composition of a single condensing component selected from silanol group-terminated polysiloxane exemplified by silanol-terminated polydimethylsiloxane synthesized in the presence of a tin-based catalyst, silanol-terminated polydiphenylsiloxane, silanol-terminated polytrifluoromethylsiloxane or silanol-terminated diphenylsiloxane/dimethylsiloxane copolymer; a composition of the silanol group-terminated polysiloxane described above and a cross-linking agent exemplified by tetraacetoxysilane, triacetoxymethyl silane, di-t-butoxydiacetoxysilane, vinyltriacetoxysilane, tetraethoxysilane, trienoxymethylsilane, bis(triethoxysilyl) ethane, tetra-n-propoxysilane, vinyltrimethoxy silane, methyltris (methylethylketoxim) silane, vinyltris (methylethylketoximino) silane, vinyltriisopropenoxysilane, triacetoxymethylsilane, tri(ethylmethyl) oximemethylsilane, bis(N-methylbenzoamido) ethoxymethylsilane, tris(cyclohexylamino) methylsilane, triacetamide methylsilane or tridimethylaminomethylsilane; or a composition of the silanol group-terminated polysiloxane described above and terminal block polysiloxane exemplified by chlor-terminated polydimethylsiloxane, diacetoxymethyl-terminated polydimethylsiloxane or terminal polysiloxane.
When the condensation cross-linking silicone rubber with which the thermally conductive filler is mixed and which has thermal conductivity is produced from these compositions, the compositions and the thermally conductive filler are kneaded and are thereafter heated at a predetermined temperature for a predetermined time and thus the condensation cross-linking silicone rubber can be obtained. Although the production conditions such as the heating temperature and the heating time differ depending on the type and characteristics of a condensation reaction, and thus they cannot be uniquely determined, in general, the heating is performed at 0 to 100° C. for 10 minutes to 24 hours. When the physical properties of the silicone rubber are excellent, a reaction time is longer under low temperature processing conditions. When quick productivity is required as compared with the physical properties, the production is performed under the processing conditions of high temperature and short time. When the processing needs to be performed within a certain time depending on the production process and the work environment, the processing temperature is set to a relatively high temperature within the range described above according to a desired processing time, and thus the production is performed.
The thermally conductive elastomer may be a blend of silicone rubber and non-silicone rubber. Examples of the non-silicone rubber include olefin rubber such as 4-cis butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, polybutene rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, chlorinated ethylene-propylene rubber, chlorinated butyl rubber, natural rubber, 1,4-cis butadiene rubber, isoprene rubber, polychloroprene, styrene-butadiene copolymer rubber, hydrogenated styrene-butadiene copolymer rubber, acrylic nitrile-butadiene copolymer rubber, hydrogenated acrylic nitrile-butadiene copolymer rubber, polybutene rubber, polyisobutylene rubber, ethylene oxide-epichlorohydrin copolymer rubber, chlorinated polyethylene rubber, chlorsulphonized polyethylene rubber, alkylated chlorsulphonized polyethylene rubber, chloroprene rubber, chlorinated acrylic rubber, brominated acrylic rubber, fluororubber, epichlorohydrin and copolymer rubber thereof, brominated butyl rubber, tetrafluoroethylene, hexafluoropropyrene, vinylidene fluoride and homopolymer rubber such as tetrafluoroloethylene, binary and ternary copolymer rubbers thereof, ethylene-tetrafluoroethylene copolymer rubber, propylene-tetrafluoroethylene copolymer rubber, ethylene acrylic rubber, epoxy rubber, urethane rubber and a cross-linking mixture of raw rubber-like materials exemplified by a linear polymer such as double-ended unsaturated group elastomer. These may be used singly or a plurality of types may be mixed to be used.
Examples of other rubber materials include ethylene-propylene-diene copolymer rubber, urethane rubber and fluororubber.
In the thermally conductive elastomer sheet 20 formed of the thermally conductive elastomer as described above, when the thickness thereof is excessively thin, it is more likely that it is difficult to perform the processing whereas when the thickness is excessively thick, it is more likely that the thermal conductivity is lowered, with the result that the thickness is preferably 1.0 to 0.1 mm (more preferably 0.5 to 0.3 mm). In the thermally conductive elastomer sheet 20 having a thickness less than 0.1 mm, there is a tendency that the strength thereof is insufficient and thus it is difficult to perform the processing whereas in the thermally conductive elastomer sheet 20 having a thickness exceeding 1.0 mm, the thermal conductivity tends to be lowered. The thermal conductivity of the thermally conductive elastomer sheet 20 is preferably 1.0 W/(m·K) or more (more preferably 10 to 3 W/(m·K)) When the thermally conductive elastomer sheet 20 whose thermal conductivity is less than 1.0 W/(m·K) is used, the heat transfer property of the thermally conductive elastomer sheet 20 tends to be lowered. Furthermore, the hardness of the thermally conductive elastomer sheet 20 measured with a type A durometer according to JIS K 6253 is 90/s or less (preferably 85/s or less). In the thermally conductive elastomer sheet 20 having a low hardness as described above, the degree of intimate contact with the corresponding surfaces of the heat transfer target members 14 and 16 can be enhanced. Even when one of the heat transfer target members 14 and 16 has minute recesses and projections, the heat transfer target members 14 and 16 can be in intimate contact with the thermally conductive elastomer sheet 20.
The thermoelectric conversion element 18 is formed by using the conductive patterns 18c to couple two different types of thermoelectric conversion element materials such as metals or semiconductors. Although the thermoelectric conversion element material is not particularly limited, examples thereof include clathrate compounds, CNTs such as bismuth-tellurium type, lead-tellurium type, antimony-tellurium type, iron-aluminum type, silicon-germanium type, silicon system and germanium type, the thermoelectric conversion element material is selected as necessary according to a usage temperature range and a connection form. Although the conductive pattern is not particularly limited, examples thereof include gold, silver, copper, aluminum and various types of alloys, conductive inks of silver, conductive inks of carbon and the like, the conductive pattern is selected as necessary according to the usage temperature range and the connection form.
The thermoelectric conversion element 18 is formed by coupling, as shown in
In the thermally conductive elastomer sheet 20 and the constituent semiconductor elements, on part or the whole of at least any one of the surfaces serving as the joint surfaces, dry treatment such as corona treatment, plasma treatment or ultraviolet irradiation treatment may be performed. Although the ultraviolet irradiation treatment is not limited as long as the ultraviolet irradiation treatment is treatment for irradiating with ultraviolet rays, the ultraviolet irradiation treatment may be general ultraviolet treatment (UV treatment) for irradiating with ultraviolet rays in a wide wavelength range or ultraviolet rays of multiple wavelengths or excimer ultraviolet treatment (excimer UV treatment) for irradiating with excimer ultraviolet rays which can be regarded as a single wavelength. By the dry treatment described above, in addition to active groups such as a hydroxyl group originally included in the surfaces, an active group can be further generated, and the active groups originally included therein and the active group generated by the activation produce, in the surfaces opposite each other, a covalent bond and specifically a strong ether bond caused by dehydration, with the result that the thermally conductive elastomer sheets 20 and the constituent semiconductor elements can be joined chemically, directly and integrally.
The thermally conductive elastomer sheets 20 and the constituent semiconductor elements may be integrally joined by a covalent bond through a molecular adhesive. In molecular adhesive treatment, functional groups in the molecules of the molecular adhesive undergo a chemical reaction of adherends and a covalent bond, and thus the constituent semiconductor elements and the thermally conductive elastomer sheets 20 are directly bonded through a covalent bond caused by the single or multiple molecules of the molecular adhesive. The molecular adhesive is a generic term for bifunctional molecules in which two functional groups undergo a chemical reaction with the constituent semiconductor elements and the thermally conductive elastomer sheets 20 serving as the adherends to form a covalent bond. Specific examples thereof include various types of coupling agents such as a silane coupling agent.
More specifically, examples of the molecular adhesive include: an amino group-containing compound such as triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol (TES) and aminoethylaminopropyl trimethoxysilane; a triazine compound which has a trialkoxysilylalkylamino group such as a triethoxysilylpropylamino group and a mercapto group or an azido group, and which is represented by chemical formula (I) below:
(in the formula (I), W is a spacer group which may be, for example, an alkylene group or an aminoalkylene group optionally having a substituent or may be a direct bond, Y is an OH group or a reactive functional group for generating an OH group by hydrolysis or desorption such as a trialkoxyalkyl group, —Z is —N3or —NR1R2 (where R1 and R2 are the same or different and are H, an alkyl group or —R3Si(R4)m(OR5)3-m[R3 and R4 are an alkyl group, R5 is H or an alkyl group and m is 0 to 2] and the alkylene group, the alkoxy group and the alkyl group are a linear, branched and/or cyclic hydrocarbon group having 1 to 12 carbon atoms and optionally having a substituent); a thiol compound having a trialkoxysilylalkyl group; an epoxy compound having a trialkyloxysilylalkyl group; and a silane coupling agent such as vinyl alkoxysiloxane polymer exemplified by CH2═CH—Si (OCH3)2—O— [Si (OCH3)2—O—]n—Si(OCH3)2—CH═CH2(n═1.8−5.7).
Examples of the molecular adhesive include commercially available silane coupling agents serving as alkoxy group-containing and amino group-free silane coupling agents, and specific examples include: vinyl group and alkoxy group-containing silane coupling agents exemplified by vinyl trimethoxysilane (KBM-1003) and vinyl triethoxysilane (KBE-1003); epoxy group and alkoxy group-containing silane coupling agents exemplified by 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM-303), 3-glycidoxypropylmethyldimethoxysilane (KBM-402), 3-glycidoxypropyltrimethoxysilane (KBM-403), 3-glycidoxypropylmethyldiethoxysilane (KBE-402) and 3-glycidoxypropyltriethoxysilane (KBE-403); styril group and alkoxy group-containing silane coupling agents exemplified by p-styryltrimethoxysilane (KBM-1403); (meta)acrylic group and alkoxy group-containing silane coupling agents exemplified by 3-methacryloxypropylmethyldimethoxysilane (KBM-502), 3-methacryloxypropyltrimethoxy silane (KBM-503), 3-methacryloxypropylmethyldiethoxysilane (KBE-502), 3-methacryloxypropylmethyldiethoxysilane (KBE-503) and 3-acryloxypropyltrimethoxysilane (KBM-5103); ureido group and alkoxy group-containing silane coupling agents exemplified by 3-ureidopropyltriethoxysilane (KBE-585); mercapto group and alkoxy group-containing silane coupling agents exemplified by 3-mercaptopropylmethyldimethoxysilane (KBM-802) and 3-mercaptopropyltrimethoxysilane (KBM-803); sulfide group and alkoxy group-containing silane coupling agents exemplified by bis(triethoxysilylpropyl) tetrasulfide (KBE-846); isocyanate group and alkoxy group-containing silane coupling agents exemplified by 3-isocyanatopropyltriethoxysilane (KBE-9007) (all the silane coupling agents described above are made by Shin-Etsu Chemical Co., Ltd.; product names); vinyl group and acetoxy-containing silane coupling agents exemplified by vinyl triacetoxysilane (Z-6075); allyl group and alkoxy group-containing silane coupling agents exemplified by allyltrimethoxysilane (Z-6825); alkyl group and alkoxy group-containing silane coupling agents exemplified by methyltrimethoxysilane (Z-6366), dimethyldimethoxysilane (Z-6329), trimethylmethoxysilane (Z-6013), methyltriethoxysilane (Z-6383), methyltriphenoxysilane (Z-6721), ethyltrimethoxysilane (Z-6321), n-propyltrimethoxysilane (Z-6265), diisopropyldimethoxysilane (Z-6258), isobutyltrimethoxysilane (Z-2306), diisobutyldimethoxysilane (Z-6275), isobutyltriethoxysilane (Z-6403), n-hexyltrimethoxysilane (Z-6583), n-hexyltriethoxysilane (Z-6586), cyclohexylmethyldimethoxysilane (Z-6187), n-octyltriethoxysilane (Z-6341) and n-decyltrimethoxysilane (Z-6210); aryl group and alkoxy group-containing silane coupling agents exemplified by phenyltrimethoxysilane (Z-6124); alkyl group and chlorosilane group-containing silane coupling agents exemplified by n-octyldimethylchlorosilane (ACS-8); and silane coupling agents of alkoxy silane exemplified by tetraethoxysilane (Z-6697) (all the silane coupling agents described above are made by Dow Toray Co., Ltd.; product names).
The alkoxy group-containing and amino group-free silane coupling agent may be a hydrosilyl group (SiH group)-containing alkoxysilyl compound such as
Examples of the alkoxy group-containing and amino group-free silane coupling agent include a hydrosilyl group-containing alkoxysilyl compound such as
The reaction of these vinyl group and SiH group may be promoted with a metal catalyst such as a platinum-containing compound to join the base material sheet and the elastomer sheet.
The alkoxy group-containing and amino group-free silane coupling agent may be an alkoxysilyl compound containing alkoxysilyl groups at both ends such as
The alkoxy group-containing and amino group-free silane coupling agent may be a hydrolytic group and silyl group-containing alkoxysilyl compound such as easily hydrolyzable organosilane below:
Examples of the alkoxy group and amino group-containing silane coupling agent include commercially available silane coupling agents, and specific examples include: amino group-containing alkoxysilyl compounds exemplified by N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (KBM-602), N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (KBM-603), N-2-(aminoethyl)-3-aminopropyltriethoxysilane (KBE-603), 3-aminopropyltrimethoxysilane (KBM-903), 3-aminopropyltriethoxysilane (KBE-903), 3-triethoxysilyl-N-(1,3-dimethyl-butylidene) propylamine (KBE-9103), N-phenyl-3-aminopropyltrimethoxysilane (KBM-573) and hydrochloride of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane (KBM-575) (all the silane coupling agents described above are made by Shin-Etsu Chemical Co., Ltd.; product names); and amino group-containing alkoxysilyl compounds exemplified by 3-aminopropyltrimethoxysilane (Z-6610), 3-aminopropyltrimethoxysilane (Z-6611), 3-(2-aminoethyl) aminopropyltrimethoxysilane (Z-6094), 3-phenylaminopropyltrimethoxysilane (Z-6883) and hydrochloride of N-[3-(trimethoxysilyl)propyl]-N′-[(ethenylphenyl)methyl-1,2-ethanediamine (Z-6032) (all the silane coupling agents described above are made by Dow Toray Co., Ltd.; product names).
Only one of the dry treatment and the molecular adhesive treatment may be performed or they may be performed alternately and continuously. For example, the joining may be performed only by the dry treatment, the joining may be performed by the molecular adhesive treatment following the dry treatment or the joining may be performed by the molecular adhesive treatment following the dry treatment and further the dry treatment. The joining may be performed only by the molecular adhesive treatment, the joining may be performed by the dry treatment following the molecular adhesive treatment or the joining may be performed by the dry treatment following the molecular adhesive treatment and further the molecular adhesive treatment.
As described above, in the thermoelectric conversion module 12 shown in
Although examples of the present invention will be described in detail below, the scope of the present invention is not limited to these examples.
Experiments were performed on the generation of electricity by the Seebeck effect in the thermoelectric conversion module 12 of the thermoelectric conversion structure 10.
Molecular adhesive treatment was performed on a thermoelectric conversion element (bismuth-telluride semiconductor element, p-n number: 73 couples). The molecular adhesive treatment was performed with an ethanol solution of vinyl triethoxysilane (made by Shin-Etsu Chemical Co., Ltd., product name: KBE-1003) used as a molecular adhesive, and thereafter drying was performed at 80° C. for 30 minutes. Then, dry treatment was performed on a thermally conductive elastomer sheet. For the thermally conductive elastomer sheet, as thermally conductive fillers, magnesium oxide (MgO) and aluminum oxide (Al2O3) were dispersed in dimethyl silicone rubber, the thermally conductive elastomer sheet was thereafter put into a 150×150×0.5 mm mold for a sheet and was cured at 150° C. for 10 minutes with a 75t pressure heating press, with the result that the thermally conductive elastomer sheet (thermal conductivity: 3 W/(m·K), hardness: A82/s) having a thickness of 0.5 mm was obtained. The thermally conductive elastomer sheet obtained was cut into 50×50 mm, dry treatment was performed with an atmospheric pressure corona surface improvement device (made by Shinko Electric & Instrumentation Co., Ltd., product name: corona master) under conditions of power supply: AC100 V, gap length: 0.5 mm, output voltage: 18.0 kV (surface voltage), power: 18 W, oscillation frequency: 20 kHz, temperature: 20° C., movement speed: 70 mm/sec and number of movements: three times, and thus the thermally conductive elastomer sheet subjected to the dry treatment was obtained. Two thermally conductive elastomer sheets obtained and subjected to the dry treatment were prepared, the thermoelectric conversion element was sandwiched vertically and was pressurized and heated at 80° C. for 30 minutes with a thermocompression press and the thermally conductive elastomer sheets were adhered to the thermoelectric conversion element 18, with the result that a thermally conductive elastomer-type thermoelectric conversion module was obtained. The hardness “A” of the thermally conductive elastomer sheet indicates that measurements were performed with a type A durometer according to JIS K 6253.
Then, as a comparative example, a general combination of ceramic and a thermoelectric conversion element was used to produce a ceramic-type thermoelectric conversion module. As the thermoelectric conversion element, the same thermoelectric conversion element as in the thermally conductive elastomer type was used. As the ceramic, a 50×50 mm aluminum oxide plate having a thickness of 0.5 mm (thermal conductivity: 30 W/(m·K)) was used. Two ceramic plates were prepared, the thermoelectric conversion element was sandwiched vertically and the ceramic and the thermoelectric conversion element were adhered with an inorganic heat-resistant adhesive (made by 3M Company, product number: TB3732), with the result that a ceramic-type thermoelectric conversion module was obtained.
(1) Thermally Conductive Elastomer-Type (without Grease) Thermoelectric Conversion Structure 10
In the produced thermoelectric conversion module 12, as shown in
Hence, a temperature difference between the heating portion 26 and the cooling portion 24 was 40° C.
A thermally conductive elastomer-type (with grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that in the thermally conductive elastomer-type (with grease) thermoelectric conversion structure 10, a silicone heat dissipation grease (made by SHENZHEN HALNZIYE ELECTRONIC COMPANY, product number: HY-880, thermal conductivity of 5 W/mK) was applied to the surface of the copper plate 26a and the thermally conductive elastomer sheet 20 on the heating side and the surface of the thermally conductive elastomer sheet 20 on the colling side and the cooling portion 24 to form a thermally conductive grease layer.
A ceramic-type (without grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10 was changed from the thermally conductive elastomer type to the ceramic type.
A ceramic-type (with grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that in the ceramic-type (without grease) thermoelectric conversion structure 10, the silicone heat dissipation grease was applied to the surface of the copper plate 26a and the ceramic on the heating side and the surface of the ceramic on the colling side and the cooling portion 24 to form a thermally conductive grease layer.
The peak power of the thermoelectric conversion element of each of the thermoelectric conversion structures was measured with a circuit shown in
As is clear from
Experiments were performed on cooling achieved by the Peltier effect in the thermoelectric conversion module 12 of the thermoelectric conversion structure 10.
In the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10, as shown in
(2) Thermally Conductive Elastomer-Type (with Grease) Thermoelectric Conversion Structure
A thermally conductive elastomer-type (with grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that in a conductive rubber-type (with grease) thermoelectric conversion structure 10, the silicone heat dissipation grease (thermal conductivity of 5 W/mK) was applied to the surface of the copper plate 26a and the thermally conductive elastomer sheet 20 on the cooling side and the surface of the thermally conductive elastomer sheet 20 on the heating side and the cooling portion 24 to form a thermally conductive grease layer.
A ceramic-type (without grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10 was changed from the thermally conductive elastomer type to the ceramic type.
A ceramic-type (with grease) thermoelectric conversion structure had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure except that in the ceramic-type (without grease) thermoelectric conversion structure 10, the silicone heat dissipation grease was applied to the surface of the copper plate 26a and the ceramic on the heating side and the surface of the ceramic on the colling side and the cooling portion 24 to form a thermally conductive grease layer.
A predetermined drive current was supplied to the thermoelectric conversion module 12, and the temperature of the copper plate 26a was detected with the temperature sensor 34. The temperature of the copper plate 26a five minutes after the start of the supply of the drive current to the thermoelectric conversion module 12 was assumed to be the minimum reached temperature. The value of the drive current supplied to the thermoelectric conversion module 12 was changed, the minimum reached temperature of each of the thermoelectric conversion elements was measured and the results thereof are shown in
As is clear from
The minimum reached temperature of the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10 was equal to the minimum reached temperature of the thermally conductive elastomer-type (with grease) thermoelectric conversion structure. Hence, the thermoelectric conversion module 12 was used, and thus even when the thermally conductive grease layer was not formed, the heat transfer characteristics of the thermoelectric conversion module 12 and the copper plate 26a and the cooling portion 24 serving as the heat transfer target members were the same as the heat transfer characteristics when the thermally conductive grease layer was formed.
In
Experiments were performed on the influence of the hardness of the elastomer sheet of the thermoelectric conversion structure 10 using the generation of electricity by the Seebeck effect in the thermoelectric conversion module 12 of the thermoelectric conversion structure 10. Since in the thermally conductive elastomer sheet 20, not only the thermal conductivity but also the hardness was changed by addition of the thermally conductive filler, a silicone elastomer sheet was used instead of the thermally conductive elastomer sheet 20, and thus the experiments were performed.
(Production of Silicone Elastomer Sheets having Different Hardnesses)
For the silicone elastomer sheet, dimethyl silicone rubber was put into a 150×150×0.5 mm mold for a sheet and was cured at 150° C. for 10 minutes with a 75t pressure heating press, with the result that a silicone sheet having a thickness of 0.5 mm was obtained. As the dimethyl silicone rubbers used, RBB-6670 (hardness: A70/s), RBB-6650 (hardness: A50/s) and RBB-6630 (hardness: A30/s) (all the dimethyl silicone rubbers described above were made by Dow Toray Co., Ltd., thermal conductivity of 0.2 W/(m·K)) were used. The hardnesses were measured with a type A durometer according to JIS K 6253.
The thermoelectric conversion structure of the thermoelectric conversion module (without grease) whose elastomer sheet had a different hardness had the same configuration as the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10 except that, instead of the thermally conductive elastomer sheet 20 of the thermally conductive elastomer-type (without grease) thermoelectric conversion structure 10, the silicone elastomer sheet having a different hardness was used.
(2) Thermoelectric Conversion Structure of Thermoelectric Conversion Module (with Grease) whose Elastomer Sheet had Different Hardness
The thermoelectric conversion structure of the thermoelectric conversion module (with grease) whose elastomer sheet had a different hardness had the same configuration as the thermally conductive elastomer-type (with grease) thermoelectric conversion structure 10 except that, instead of the thermally conductive elastomer sheet 20 of the thermally conductive elastomer-type (with grease) thermoelectric conversion structure 10, the silicone elastomer sheet having a different hardness was used.
The peak power of the thermoelectric conversion element of each of the thermoelectric conversion structures whose elastomer sheets had different hardnesses was measured with the circuit shown in
The peak power of the thermoelectric conversion structure shown in
Experiments were performed on the influence of the thermal conductivity of the thermally conductive elastomer sheet 20 of the thermoelectric conversion structure 10 using the generation of electricity by the Seebeck effect in the thermoelectric conversion module 12 of the thermoelectric conversion structure 10.
(Production of Thermoelectric Conversion Module 12 in which Thermally Conductive Elastomer Sheet 20 had Different Thermal Conductivity)
A thermoelectric conversion module was produced in the same manner as the thermally conductive elastomer-type thermoelectric conversion module 12 except that as the thermally conductive elastomer sheet 20 of the thermally conductive elastomer-type thermoelectric conversion module 12, a thermally conductive elastomer sheet having a different thermal conductivity was used. For the thermally conductive elastomer sheet, as thermally conductive fillers, magnesium oxide (MgO) and aluminum oxide (Al2O3) were dispersed in dimethyl silicone rubber so as to achieve a predetermined thermal conductivity, the thermally conductive elastomer sheet was thereafter put into a 150×150×0.5 mm mold for a sheet and was cured at 150° C. for 10 minutes with a 75t pressure heating press, with the result that the thermally conductive elastomer sheet having a thickness of 0.5 mm was obtained. Three types of thermally conductive elastomer sheets having a thermal conductivity of 5.0 W/(m·K) (hardness: A80/s), a thermal conductivity of 3.0 W/(m·K) (hardness: A83/s) and a thermal conductivity of 0.2 W/(m·K) (hardness: A70/s) were compared.
The peak power of the thermoelectric conversion element of each of the thermoelectric conversion structures using thermally conductive elastomer sheets having different thermal conductivities was measured with the circuit shown in
As is clear from
In the thermoelectric conversion structure according to the present invention, satisfactory heat transfer characteristics are provided without the formation of a thermally conductive grease layer between the thermoelectric conversion module and the heat transfer target members, and thus the productivity of the thermoelectric conversion structure can be enhanced, and the thermoelectric conversion structure can be applied to an application for removing the thermoelectric conversion module from the heat transfer target members and to a human body.
10: thermoelectric conversion structure, 12: thermoelectric conversion module, 14 and 16: heat transfer target members, 16a: copper plate, 18: thermoelectric conversion element, 18a: n-type semiconductor element, 18b: p-type semiconductor e0lement, 18c: conductive pattern, 20: thermally conductive elastomer sheet, 24: cooling portion, 26: heating portion, 26a: copper plate, 26b: heating Peltier device, 26c: heat sink, 26d and 34: temperature sensors, 30: stage.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-003755 | Jan 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/001084 | 1/14/2021 | WO |
