KR20110040083A - Aluminium paste for a back electrode of solar cell - Google Patents
Aluminium paste for a back electrode of solar cell Download PDFInfo
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- KR20110040083A KR20110040083A KR1020090097217A KR20090097217A KR20110040083A KR 20110040083 A KR20110040083 A KR 20110040083A KR 1020090097217 A KR1020090097217 A KR 1020090097217A KR 20090097217 A KR20090097217 A KR 20090097217A KR 20110040083 A KR20110040083 A KR 20110040083A
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 129
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 85
- 239000004411 aluminium Substances 0.000 title 1
- 239000011521 glass Substances 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 5
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 claims description 5
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 5
- 238000004383 yellowing Methods 0.000 abstract description 4
- 235000012431 wafers Nutrition 0.000 description 25
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 20
- 229910052710 silicon Inorganic materials 0.000 description 20
- 239000010703 silicon Substances 0.000 description 20
- 238000000034 method Methods 0.000 description 19
- 238000010304 firing Methods 0.000 description 16
- -1 glycerin ester Chemical class 0.000 description 9
- 238000007639 printing Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 239000002952 polymeric resin Substances 0.000 description 6
- 229920003002 synthetic resin Polymers 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229940051841 polyoxyethylene ether Drugs 0.000 description 5
- 229920000056 polyoxyethylene ether Polymers 0.000 description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 229910052709 silver Inorganic materials 0.000 description 4
- 239000004332 silver Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 229910004205 SiNX Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 235000014113 dietary fatty acids Nutrition 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 3
- 239000000194 fatty acid Substances 0.000 description 3
- 229930195729 fatty acid Natural products 0.000 description 3
- 238000007650 screen-printing Methods 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- 239000013008 thixotropic agent Substances 0.000 description 3
- ULQISTXYYBZJSJ-UHFFFAOYSA-N 12-hydroxyoctadecanoic acid Chemical compound CCCCCCC(O)CCCCCCCCCCC(O)=O ULQISTXYYBZJSJ-UHFFFAOYSA-N 0.000 description 2
- 239000001856 Ethyl cellulose Substances 0.000 description 2
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerol Natural products OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- 239000002202 Polyethylene glycol Substances 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229920001249 ethyl cellulose Polymers 0.000 description 2
- 235000019325 ethyl cellulose Nutrition 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 150000004665 fatty acids Chemical class 0.000 description 2
- 235000011187 glycerol Nutrition 0.000 description 2
- 239000003906 humectant Substances 0.000 description 2
- DNIAPMSPPWPWGF-UHFFFAOYSA-N monopropylene glycol Natural products CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 2
- 229920001223 polyethylene glycol Polymers 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- DAFHKNAQFPVRKR-UHFFFAOYSA-N (3-hydroxy-2,2,4-trimethylpentyl) 2-methylpropanoate Chemical compound CC(C)C(O)C(C)(C)COC(=O)C(C)C DAFHKNAQFPVRKR-UHFFFAOYSA-N 0.000 description 1
- IBLKWZIFZMJLFL-UHFFFAOYSA-N 1-phenoxypropan-2-ol Chemical compound CC(O)COC1=CC=CC=C1 IBLKWZIFZMJLFL-UHFFFAOYSA-N 0.000 description 1
- 229940114072 12-hydroxystearic acid Drugs 0.000 description 1
- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 description 1
- WMDZKDKPYCNCDZ-UHFFFAOYSA-N 2-(2-butoxypropoxy)propan-1-ol Chemical compound CCCCOC(C)COC(C)CO WMDZKDKPYCNCDZ-UHFFFAOYSA-N 0.000 description 1
- GZMAAYIALGURDQ-UHFFFAOYSA-N 2-(2-hexoxyethoxy)ethanol Chemical compound CCCCCCOCCOCCO GZMAAYIALGURDQ-UHFFFAOYSA-N 0.000 description 1
- XYVAYAJYLWYJJN-UHFFFAOYSA-N 2-(2-propoxypropoxy)propan-1-ol Chemical compound CCCOC(C)COC(C)CO XYVAYAJYLWYJJN-UHFFFAOYSA-N 0.000 description 1
- COBPKKZHLDDMTB-UHFFFAOYSA-N 2-[2-(2-butoxyethoxy)ethoxy]ethanol Chemical compound CCCCOCCOCCOCCO COBPKKZHLDDMTB-UHFFFAOYSA-N 0.000 description 1
- JDSQBDGCMUXRBM-UHFFFAOYSA-N 2-[2-(2-butoxypropoxy)propoxy]propan-1-ol Chemical compound CCCCOC(C)COC(C)COC(C)CO JDSQBDGCMUXRBM-UHFFFAOYSA-N 0.000 description 1
- WFSMVVDJSNMRAR-UHFFFAOYSA-N 2-[2-(2-ethoxyethoxy)ethoxy]ethanol Chemical compound CCOCCOCCOCCO WFSMVVDJSNMRAR-UHFFFAOYSA-N 0.000 description 1
- WAEVWDZKMBQDEJ-UHFFFAOYSA-N 2-[2-(2-methoxypropoxy)propoxy]propan-1-ol Chemical compound COC(C)COC(C)COC(C)CO WAEVWDZKMBQDEJ-UHFFFAOYSA-N 0.000 description 1
- UPGSWASWQBLSKZ-UHFFFAOYSA-N 2-hexoxyethanol Chemical compound CCCCCCOCCO UPGSWASWQBLSKZ-UHFFFAOYSA-N 0.000 description 1
- QCDWFXQBSFUVSP-UHFFFAOYSA-N 2-phenoxyethanol Chemical compound OCCOC1=CC=CC=C1 QCDWFXQBSFUVSP-UHFFFAOYSA-N 0.000 description 1
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229910021364 Al-Si alloy Inorganic materials 0.000 description 1
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 125000002877 alkyl aryl group Chemical group 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- XXJWXESWEXIICW-UHFFFAOYSA-N diethylene glycol monoethyl ether Chemical compound CCOCCOCCO XXJWXESWEXIICW-UHFFFAOYSA-N 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- HHFAWKCIHAUFRX-UHFFFAOYSA-N ethoxide Chemical compound CC[O-] HHFAWKCIHAUFRX-UHFFFAOYSA-N 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000007646 gravure printing Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 238000007645 offset printing Methods 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920002503 polyoxyethylene-polyoxypropylene Polymers 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000600 sorbitol Substances 0.000 description 1
- JMXKSZRRTHPKDL-UHFFFAOYSA-N titanium ethoxide Chemical compound [Ti+4].CC[O-].CC[O-].CC[O-].CC[O-] JMXKSZRRTHPKDL-UHFFFAOYSA-N 0.000 description 1
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 1
- RBNWAMSGVWEHFP-UHFFFAOYSA-N trans-p-Menthane-1,8-diol Chemical compound CC(C)(O)C1CCC(C)(O)CC1 RBNWAMSGVWEHFP-UHFFFAOYSA-N 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- AJSTXXYNEIHPMD-UHFFFAOYSA-N triethyl borate Chemical compound CCOB(OCC)OCC AJSTXXYNEIHPMD-UHFFFAOYSA-N 0.000 description 1
- JLGLQAWTXXGVEM-UHFFFAOYSA-N triethylene glycol monomethyl ether Chemical compound COCCOCCOCCO JLGLQAWTXXGVEM-UHFFFAOYSA-N 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/20—Conductive material dispersed in non-conductive organic material
- H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
- H01L31/056—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means the light-reflecting means being of the back surface reflector [BSR] type
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/52—PV systems with concentrators
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Power Engineering (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Sustainable Energy (AREA)
- Sustainable Development (AREA)
- Life Sciences & Earth Sciences (AREA)
- Photovoltaic Devices (AREA)
- Conductive Materials (AREA)
Abstract
Description
본 발명은 태양전지의 후면 전극용 알루미늄 페이스트에 관한 것이다.The present invention relates to an aluminum paste for a back electrode of a solar cell.
실리콘 결정형 태양전지는, P형 실리콘 웨이퍼 표면에 인(P)을 확산시킴으로써 PN접합을 형성하고, 여기에 입사되는 태양빛의 반사손실을 줄이기 위하여 반사방지막을 코팅하고, 이렇게 구성된 웨이퍼의 전면 N층에 Ag 전극을 형성하고, 후면 P층에 Ag와 Al전극을 형성함으로써 구성된다. 전면 전극으로 사용되는 은-페이스트는 실리콘의 N-측에 연결되어 전극을 형성하고, 알루미늄 페이스트는 실리콘의 후면, 즉 P층과 연결되어 전극을 형성한다.Silicon crystalline solar cells form a PN junction by diffusing phosphorus (P) on the surface of a P-type silicon wafer, coating an antireflection film to reduce the reflection loss of sunlight incident thereon, and the front N layer of the wafer thus configured. It is configured by forming an Ag electrode on the substrate and forming an Ag and an Al electrode on the backside P layer. The silver paste used as the front electrode is connected to the N-side of silicon to form an electrode, and the aluminum paste is connected to the backside of silicon, that is, the P layer, to form an electrode.
실리콘 결정형 태양전지는 일반적으로 두께가 180-220μm인 P형 실리콘 기판을 사용한다. 상기 기판의 전면부에는 0.2-0.6μm 두께의 n형 불순물층이 형성되고, 그 위에 반사 방지를 위한 SiNx층과 전면 전극이 형성된다. 후면부에는 알루미늄 전극이 형성되는데, 알루미늄 전극은 알루미늄 페이스트를 스크린 인쇄 등에 의해 도포하고 이를 건조한 후, 저온(약 600℃)과 고온(800-950℃)의 2단 소성과정을 거쳐 형성된다. 이러한 소성과정에서 알루미늄이 P형 실리콘 웨이퍼의 내부로 확산 되면서 Al-Si 합금층이 형성된다. 이러한 확산층(P+층)에 의해, 태양전지에서 생성되는 전자의 재결합을 방지하고 생성된 캐리어(Carrier)의 수집 효율을 향상시키는 BSF(Back Surface Field)가 형성된다. 이렇게 형성되는 BSF층의 두께 및 균일도에 따라 태양전지의 효율이 좌우되는데 두께가 얇아지면 태양전지의 효율이 저하되고 두꺼워지면 효율이 상승된다. Silicon crystalline solar cells generally use P-type silicon substrates with a thickness of 180-220 μm. An n-type impurity layer having a thickness of 0.2-0.6 μm is formed on the front surface of the substrate, and a SiNx layer and a front electrode are formed thereon to prevent reflection. An aluminum electrode is formed on the rear side. The aluminum electrode is formed by applying an aluminum paste by screen printing and the like and drying it, followed by a two-stage baking process of low temperature (about 600 ° C.) and high temperature (800-950 ° C.). In this firing process, aluminum diffuses into the P-type silicon wafer to form an Al-Si alloy layer. The diffusion layer (P + layer) forms a back surface field (BSF) that prevents recombination of electrons generated in the solar cell and improves the collection efficiency of the generated carriers. The efficiency of the solar cell depends on the thickness and uniformity of the BSF layer formed as described above. As the thickness becomes thinner, the efficiency of the solar cell decreases and the efficiency increases when the thickness becomes thicker.
한편, 최근 태양전지의 비용절감을 도모하기 위하여 실리콘 웨이퍼의 기판을 얇게 하는 것이 추세인데, 실리콘 웨이퍼의 두께를 얇게 하면 실리콘 웨이퍼와 알루미늄의 팽창계수 차이로 인하여 웨이퍼의 휨이 발생하며, 그에 따라 웨이퍼 갈라짐 등의 현상도 발생된다.On the other hand, in recent years, in order to reduce the cost of solar cells, it is a trend to thin the substrate of the silicon wafer. When the thickness of the silicon wafer is thinned, the warpage of the wafer occurs due to the difference in the expansion coefficient between the silicon wafer and the aluminum, and thus the wafer Phenomena such as cracking also occur.
이러한 문제를 개선하기 위하여, 후면 전극인 알루미늄 전극의 두께를 얇게 형성할 필요가 있으며, 이는 알루미늄 페이스트의 도포량을 줄이는 방법으로 달성될 수 있다. 그러나, 알루미늄 페이스트의 도포량을 줄이게 되면 후면 전계층인 BSF층의 두께가 감소되어 태양전지의 효율이 저하될 뿐만 아니라, 소성공정 중에 전극층에 알루미늄 기포나 범프(Bμmp)의 발생이 증가하는 문제가 야기된다. 이와 같이 발생된 알루미늄 기포나 돌출부위인 범프(Bμmp)는 웨이퍼 후면의 평활도를 떨어뜨리며, 그들로 응력이 집중됨에 따라, 태양전지의 제조 공정이나 모듈제조 공정에서 전지의 깨짐을 야기한다. In order to improve this problem, it is necessary to form a thin thickness of the aluminum electrode, which is the rear electrode, which can be achieved by reducing the amount of the aluminum paste applied. However, if the coating amount of aluminum paste is reduced, the thickness of the BSF layer, which is the rear electric field layer, is reduced, which reduces the efficiency of the solar cell, and also causes the problem that the generation of aluminum bubbles or bumps (Bμmp) increases in the electrode layer during the firing process. do. The aluminum bubbles or bumps (Bμmp) generated as described above decrease the smoothness of the back surface of the wafer, and as stress is concentrated thereon, the battery breaks in the solar cell manufacturing process or the module manufacturing process.
소성공정 중에 태양전지의 휨이나 알루미늄 기포의 발생을 감소시키기 위하여 제안된 종래의 기술로는 다음과 같은 것들이 있다. 대한민국 등록특허공보 제 10-0825580에는 0.5-10μm 크기의 알루미늄 분말과 유기비히클에 금속알콕사이드를 첨가한 알루미늄 페이스트가 기재되어 있으며, 대한민국 특허공개공보 제10-2008-0068638에는 2-20μm 크기의 알루미늄 분말, 글라스 프릿, 유기 비히클과 더불어 금속 수산화물을 포함하는 알루미늄 페이스트가 기재되어 있으며, 대한민국 특허공개공보 제10-2008-0057230에는 2-20μm 크기의 알루미늄 분말, 글라스 프릿, 유기 비히클과 더불어 가소제를 포함하는 알루미늄 페이스트가 기재되어 있으며, 또한 대한민국 특허공개공보 제10-2008-0104179에는 4-10μm 크기의 알루미늄 입자와 알칼리계 글라스 프릿을 포함하고, 여기에 보론 에톡사이드(Boron Ethoxide), 티타늄 에톡사이드(Titaniμm Ethoxide), 흄실리카(Fμmed silica) 등을 첨가한 알루미늄 페이스트가 기재되어 있다.Conventional techniques proposed to reduce the warpage of the solar cells and the generation of aluminum bubbles during the firing process are as follows. Korean Patent Publication No. 10-0825580 describes aluminum powder having a size of 0.5-10 μm and aluminum paste having metal alkoxide added to an organic vehicle, and Korean Patent Publication No. 10-2008-0068638 describes an aluminum powder having a size of 2-20 μm. And aluminum paste containing metal hydroxides in addition to glass frit and organic vehicle, and Korean Patent Publication No. 10-2008-0057230 includes a plasticizer in addition to aluminum powder, glass frit and organic vehicle having a size of 2-20 μm. Aluminum paste is described, and also the Republic of Korea Patent Publication No. 10-2008-0104179 includes 4-10μm aluminum particles and alkali glass frit, including boron ethoxide, titanium ethoxide (Titaniμm) Aluminum paste with Ethoxide, Fμmed silica, etc. is described. .
그러나 상기 특허문헌들에 소개된 알루미늄 페이스트들은 모두 알루미늄과 글라스 프릿, 유기 비히클 외에 유기 또는 무기 첨가제들을 포함하고 있다. 그런데, 이러한 첨가제들은 페이스트의 소성 과정에서 잔류물로 남거나 공극으로 존재하여 페이스트의 저항을 떨어트릴 뿐만 아니라, 균일도를 저하시켜서 태양전지의 효율에 악영향을 미치는 문제를 야기한다. 또한 상기 알루미늄 페이스트들은 알루미늄 입자의 크기가 최대 10-20μm이기 때문에 텍스쳐링(texturing)된 태양전지의 후면 표면과 균일한 접촉을 형성하기 어려우므로, 내부 기공에 의해 알루미늄 범프(bμmp)가 발생될 가능성이 높은 단점을 갖는다.However, the aluminum pastes introduced in the above patent documents all contain organic or inorganic additives in addition to aluminum, glass frit, and organic vehicle. However, these additives remain as residues or voids in the firing process of the paste, which not only lowers the resistance of the paste, but also lowers the uniformity, thereby causing a problem that adversely affects the efficiency of the solar cell. In addition, since the aluminum pastes have a maximum particle size of 10-20 μm, it is difficult to form a uniform contact with the back surface of the textured solar cell, so that aluminum bumps (bμmp) may be generated by internal pores. Has a high disadvantage.
본 발명은, 종래기술의 상기와 같은 문제를 해결하기 위한 것으로서, 소성 공정 중에 태양전지의 휨이나 알루미늄 후면 전극 층에 대한 알루미늄 기포, 범프(Bμmp) 및 황변의 발생을 최소화하며, Isc 및 Voc 값을 크게 향상시킬 뿐만 아니라, 태양전지의 효율도 획기적으로 향상시키는 태양전지 후면 전극용 알루미늄 페이스트를 제공하는 것을 목적으로 한다.The present invention is to solve the above problems of the prior art, to minimize the generation of aluminum bubbles, bumps (Bμmp) and yellowing of the solar cell warpage or aluminum back electrode layer during the firing process, Isc and Voc value It is an object of the present invention to provide an aluminum paste for solar cell back electrode that not only greatly improves the efficiency but also significantly improves the efficiency of the solar cell.
본 발명은 D50=4~6㎛인 알루미늄 분말과 D50=2~4㎛인 알루미늄 분말을 6:4 ~ 9.5:0.5의 중량비로 혼합한 알루미늄 분말을 포함하는 것을 특징으로 하는 태양전지 후면 전극용 알루미늄 페이스트를 제공한다. The present invention is a solar cell rear electrode comprising an aluminum powder of D 50 = 4 ~ 6㎛ aluminum powder and D 50 = 2 ~ 4㎛ aluminum powder mixed in a weight ratio of 6: 4 to 9.5: 0.5 To provide aluminum paste.
또한, 본 발명은 In addition,
상기의 알루미늄 페이스트를 사용하여 후면 전극을 형성하는 공정을 포함하는 것을 특징으로 하는 태양전지의 제조방법을 제공한다.It provides a solar cell manufacturing method comprising the step of forming a back electrode using the aluminum paste.
본 발명은 알루미늄 페이스트 조성물은 평균 입자 크기가 다른 2종 이상의 알루미늄 분말을 사용하여 텍스쳐링되어 있는 실리콘 웨이퍼와 알루미늄 페이스트 간의 접촉을 향상시킴으로써 소성 공정 중에 태양전지의 휨이나 알루미늄 후면 전극 층에 대한 알루미늄 기포, 범프(Bμmp) 및 황변의 발생을 최소화하며, Isc 및 Voc 값을 크게 향상시킬 뿐만 아니라, 태양전지의 효율도 획기적으로 향상시킨다.According to the present invention, the aluminum paste composition may improve the contact between the silicon wafer and the aluminum paste, which is textured using two or more kinds of aluminum powders having different average particle sizes, so that the aluminum foam to the warpage of the solar cell or the aluminum back electrode layer during the baking process, It minimizes the occurrence of bumps (Bμmp) and yellowing, greatly improves Isc and Voc values, and dramatically improves the efficiency of solar cells.
본 발명은 D50=4~6㎛인 알루미늄 분말과 D50=2~4㎛인 알루미늄 분말을 6:4 ~ 9.5:0.5의 중량비로 혼합한 알루미늄 분말을 포함하는 것을 특징으로 하는 태양전지 후면 전극용 알루미늄 페이스트에 관한 것이다.The present invention is a solar cell rear electrode comprising an aluminum powder of D 50 = 4 ~ 6㎛ aluminum powder and D 50 = 2 ~ 4㎛ aluminum powder mixed in a weight ratio of 6: 4 to 9.5: 0.5 It is related with the aluminum paste for.
일반적으로 실리콘 태양전지의 경우 태양빛의 수광면적을 넓히기 위하여 앞뒤 표면을 텍스쳐링(texturing) 하게 된다. 일반적으로 단결정 텍스쳐링의 형태는 피라미드 형태의 구조를 갖게 되는데 이러한 피라미드 구조의 높이는 2 μm~15μm / 폭은 2μm~20μm 내외로 형성된다. 또한 다결정 실리콘 텍스쳐링은 불규칙한 미로형태의 구조를 갖는다. 이러한 구조를 갖는 실리콘 웨이퍼상에 스크린 인쇄, 그라비아 인쇄 또는 옵셋인쇄를 통해 후면 알루미늄 페이스트를 인쇄하고 건조한 후, 소성 공정을 거쳐 알루미늄 전극을 형성한다. 이러한 공정에서 알루미늄 입자의 크기가 너무 크게 되면 알루미늄 페이스트와 실리콘 웨이퍼와의 접촉이 잘 이루어지지 않고, 인쇄 및 건조 후에 페이스트와 실리콘 웨이퍼의 텍스쳐 구조 사이에 공극이 형성된다. 이러한 공극은 소성과정을 진행하는 동안 알루미늄 페이스트층을 통과하여 알루미늄 전극 표면으로 분출되는데, 이러한 과정과 동반하여 알루미늄의 범프(bump)와 기포가 발생하게 된다. In general, in the case of silicon solar cells, the front and rear surfaces are textured to broaden the light receiving area of sunlight. In general, the form of single crystal texturing has a pyramidal structure, and the height of the pyramid structure is about 2 μm to 15 μm and the width is about 2 μm to 20 μm. In addition, polycrystalline silicon texturing has an irregular maze structure. The backside aluminum paste is printed and dried on the silicon wafer having such a structure by screen printing, gravure printing or offset printing, and then formed through the firing process to form an aluminum electrode. In this process, when the size of the aluminum particles is too large, the aluminum paste is not in contact with the silicon wafer well, and voids are formed between the paste and the texture structure of the silicon wafer after printing and drying. These pores are ejected through the aluminum paste layer to the surface of the aluminum electrode during the firing process, and bumps and bubbles of aluminum are generated along with this process.
또한, 본 발명자들은 예의 연구 결과, 단일 입도분포를 갖는 알루미늄 분말을 사용할 경우 공극을 원활히 채울 수가 없으며, 평균 입자 크기가 다른 2종 이상의 알루미늄 분말을 사용하는 경우에 실리콘 웨이퍼의 텍스쳐 구조 사이의 공극을 최소화 할 수 있음을 확인하였다.In addition, the inventors of the present invention have shown that, when using aluminum powder having a single particle size distribution, the present inventors cannot smoothly fill the voids, and when two or more kinds of aluminum powders having different average particle sizes are used, the gaps between the texture structures of the silicon wafers can be reduced. It was confirmed that it can be minimized.
그러므로, 본 발명의 태양전지 후면 전극용 알루미늄 페이스트는 D50=4~6㎛인 알루미늄 분말과 D50=2~4㎛인 알루미늄 분말이 6:4 ~ 9.5:0.5의 중량비로 혼합된 알루미늄 분말을 포함하는 것을 특징으로 한다.Therefore, the aluminum paste for solar cell rear electrode of the present invention is an aluminum powder in which D 50 = 4 ~ 6 ㎛ aluminum powder and D 50 = 2 ~ 4 ㎛ aluminum powder mixed in a weight ratio of 6: 4 ~ 9.5: 0.5 It is characterized by including.
상기와 같은 범위의 입도분포를 갖는 알루미늄 분말을 사용하여 페이스트를 제조하게 되면, 웨이퍼의 텍스쳐링 구조사이에 깊숙이 페이스트가 침투할 수 있을 뿐만 아니라 페이스트 내의 공극률도 감소된다. 따라서, 후면 BSF층이 균일하게 형성되고 알루미늄 전극의 저항도 낮아지며, 웨이퍼의 휨도 억제된다. 그러므로, 상기와 같은 알루미늄 분말을 사용하여 제조되는 태양전지는 최대출력전류(Isc)가 상승되고 효율도 증가된다. 또한, 소성공정 후 알루미늄 전극에서 발생하는 황변 현상이 방지되는 효과도 얻을 수 있다.When the paste is manufactured using aluminum powder having a particle size distribution in the above range, not only the paste can penetrate deeply between the texturing structures of the wafer but also the porosity in the paste is reduced. Therefore, the back side BSF layer is formed uniformly, the resistance of the aluminum electrode is also lowered, and the warping of the wafer is also suppressed. Therefore, in the solar cell manufactured using the aluminum powder as described above, the maximum output current Isc is increased and the efficiency is also increased. In addition, it is also possible to obtain an effect of preventing the yellowing phenomenon occurring in the aluminum electrode after the firing process.
또한, 본 발명은, 페이스트 총 중량에 대하여, (a) D50=4~6㎛인 알루미늄 분말과 D50=2~4㎛인 알루미늄 분말을 6:4 ~ 9.5:0.5의 중량비로 혼합한 알루미늄 분말 65~75 중량%; (b) 글라스 프릿 0.01~5 중량%; 및 (c) 유기 비히클 용액 20~34.90 중량%를 포함하는 태양전지 후면 전극용 알루미늄 페이스트에 관한 것이다.In addition, the present invention relates to an aluminum in which (a) an aluminum powder having D 50 = 4 to 6 µm and an aluminum powder having D 50 = 2 to 4 µm are mixed at a weight ratio of 6: 4 to 9.5: 0.5 with respect to the total weight of the paste. Powder 65-75 wt%; (b) 0.01-5% by weight of glass frit; And (c) 20 to 34.90 wt% of an organic vehicle solution.
본 발명의 알루미늄 페이스트에 포함되는 상기 (a) 알루미늄 분말은, 페이스트 총 중량에 대하여 65~75 중량%로 포함되는 것이 바람직하다. 65 중량% 미만으로 포함되면 소성 후 인쇄된 알루미늄 층이 얇아져 후면 BSF층이 충분히 형성되지 않아 효율이 떨어지는 문제가 발생하며, 75 중량%를 초과하면 인쇄두께가 너무 두꺼워 지고 이로 인해 실리콘 웨이퍼의 휨을 초래할 수 있다.It is preferable that the said (a) aluminum powder contained in the aluminum paste of this invention is contained in 65 to 75 weight% with respect to the paste total weight. If the content is less than 65% by weight, the printed aluminum layer becomes thinner after firing, so that the rear BSF layer is not sufficiently formed, resulting in a problem of inefficiency. If the content exceeds 75% by weight, the printing thickness becomes too thick, which may cause warpage of the silicon wafer. Can be.
본 발명의 알루미늄 페이스트에 포함되는 상기 (b) 글라스 프릿은 페이스트 총 중량에 대하여 0.01~5 중량%, 바람직하게는 0.05~3 중량%, 더욱 바람직하게는 0.1~1 중량%로 포함된다. 글리스프릿이 0.01 중량% 미만으로 포함되면 웨이퍼의 휨(Bowing)이 증가하고 부착력이 떨어지는 문제가 발생되고, 5 중량%를 초과하여 포함되면 저항이 높아져 태양전지의 효율이 떨어지는 문제가 발생된다.The (b) glass frit included in the aluminum paste of the present invention is contained in an amount of 0.01 to 5% by weight, preferably 0.05 to 3% by weight, and more preferably 0.1 to 1% by weight, based on the total weight of the paste. When the glysprit is included in less than 0.01% by weight, the warpage of the wafer is increased and adhesion is reduced. When the content is included in an amount of more than 5% by weight, the resistance is increased, resulting in a decrease in efficiency of the solar cell.
상기 글라스 프릿으로는 예컨대, Bi2O3-Al2O3-SiO2-SrO-B2O3계를 들 수 있다. 상기 글라스 프릿의 조성비는 특별히 한정되는 것은 아니지만 Bi2O3 20~30mol%, Al2O3 5~15mol%, SiO2 25~35mol%, SrO 1~10mol% 및 B2O3 20~40mol%의 조성을 갖는 것이 바람직하다. Examples of the glass frit include a Bi 2 O 3 -Al 2 O 3 -SiO 2 -SrO-B 2 O 3 system. The composition ratio of the glass frit is not particularly limited, but 20 to 30 mol% of Bi 2 O 3 , 5 to 15 mol% of Al 2 O 3 , 25 to 35 mol% of SiO 2 , 1 to 10 mol% of SrO, and 20 to 40 mol% of B 2 O 3. It is preferable to have a composition of.
또한, 본 발명에서 사용되는 글라스 프릿은 연화점이 400~600℃인 것이 바 람직하다. 글라스 프릿의 연화점이 400℃ 미만인 경우에는 글라스 프릿의 열팽창계수가 상대적으로 커져 이로 인해 태양전지 제조 공정 중 소성공정을 거친 후 웨이퍼의 휨을 증가시키는 문제가 발생하며, 600℃를 초과하는 경우에는 글라스 프릿이 용융되어 알루미늄 층과 실리콘 웨이퍼 층 사이에서 밀착성을 부여해야 되는데 소성과정에서 글라스 프릿이 충분히 용융되지 않아 밀착성이 저하되는 문제가 발생할 수 있다.In addition, the glass frit used in the present invention is preferably a softening point of 400 ~ 600 ℃. If the softening point of the glass frit is less than 400 ℃, the coefficient of thermal expansion of the glass frit is relatively large, which causes a problem of increasing the warpage of the wafer after the firing process during the solar cell manufacturing process. This melted to give the adhesion between the aluminum layer and the silicon wafer layer, but the glass frit is not sufficiently melted during the firing process may cause a problem that the adhesion is reduced.
본 발명의 알루미늄 페이스트에 포함되는 상기 (c) 유기 비히클 용액은 페이스트 총 중량에 대하여 20~34.90 중량%로 포함되는 것이 바람직하다. 유기 비히클 용액이 20 중량% 미만으로 포함되면 점도가 너무 높아져 인쇄성이 떨어지는 문제가 발생되고, 34.90 중량%를 초과하여 포함되면 알루미늄 함유량이 떨어져 충분한 알루미늄 층의 두께를 확보하기 어려운 문제가 발생된다. (C) The organic vehicle solution included in the aluminum paste of the present invention is preferably included in 20 to 34.90% by weight based on the total weight of the paste. If the organic vehicle solution is included in less than 20% by weight, the viscosity is too high, the printability is inferior, and when included in excess of 34.90% by weight, the aluminum content is lowered, it is difficult to secure a sufficient thickness of the aluminum layer.
상기 유기 비히클 용액은 유기용매에 고분자 수지를 녹여서 제조하며, 필요에 따라, 요변성제, 습윤제, 첨가제 등을 더 포함할 수 있다.The organic vehicle solution is prepared by dissolving a polymer resin in an organic solvent, and may further include a thixotropic agent, a humectant, an additive, and the like, as necessary.
본 발명에 사용되는 유기 비히클 용액은 용액 총 중량에 대하여, 75 중량% 이상의 용매, 1~25중량%의 고분자 수지, 약 5 중량% 이하의 습윤제와 요변성제, 및 1~10 중량% 첨가제를 더 포함할 수 있다. The organic vehicle solution used in the present invention further contains at least 75% by weight of solvent, 1-25% by weight of polymer resin, up to about 5% by weight of wetting agent and thixotropic agent, and 1-10% by weight of additive, based on the total weight of the solution. It may include.
상기 용매로는 인쇄공정 중 페이스트의 건조를 막고 유동성을 조절할 수 있도록 약 150-300℃ 범위의 끊는점을 갖는 용매가 적합하다. 널리 사용되는 용매로는 글리콜 에테르 계열로 트리프로필렌글리콜 메틸에테르, 디프로필렌글리콜 n-프 로필에테르, 디프로필렌글리콜 n-부틸에테르, 트리프로필렌글리콜 n-부틸에테르, 프로필렌글리콜 페닐에테르, 디에틸렌글리콜 에틸에테르, 디에틸렌글리콜 n-부틸에테르, 디에틸렌글리콜 헥실에테르, 에틸렌글리콜 헥실에테르, 트리에틸렌글리콜 메틸에테르, 트리에틸렌글리콜 에틸에테르, 트리에틸렌글리콜 n-부틸에테르, 에틸렌글리콜 페닐에테르, 터피놀, Texanol® 에틸렌글리콜 등을 들 수 있다.As the solvent, a solvent having a breaking point in the range of about 150-300 ° C. is suitable to prevent drying of the paste during the printing process and to control fluidity. Widely used solvents include glycol ether-based tripropylene glycol methyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether, diethylene glycol ethyl Ether, diethylene glycol n-butyl ether, diethylene glycol hexyl ether, ethylene glycol hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol n-butyl ether, ethylene glycol phenyl ether, terpinol, Texanol ® can be given ethylene glycol, and the like.
상기 고분자 수지로는 폴리비닐피롤리돈, 폴리비닐알코올, 폴리에틸렌글리콜, 에틸셀룰로오스, 로진, 페놀 수지, 아크릴 수지 등을 들 수 있다. 고분자 수지의 함량은 유기 비히클 용액 총 중량에 대하여 1~25 중량%, 바람직하게는 5~25 중량%가 좋다. 고분자수지의 첨가량이 1 중량% 미만일 경우 페이스트의 인쇄성 및 분산 안정성이 저하되고, 25 중량%를 초과할 경우에는 페이스트가 인쇄되지 않는 문제를 초래 할 수 있다.Examples of the polymer resin include polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, ethyl cellulose, rosin, phenol resin, acrylic resin and the like. The content of the polymer resin is 1 to 25% by weight, preferably 5 to 25% by weight based on the total weight of the organic vehicle solution. If the amount of the polymer resin is less than 1% by weight, the printability and dispersion stability of the paste may be lowered. If the amount of the polymer resin exceeds 25% by weight, the paste may not be printed.
상기 요변성제 및 습윤제로는 이 분야에서 일반적으로 사용되는 것을 제한 없이 사용할 수 있다.As the thixotropic agent and the humectant, any one generally used in the art may be used without limitation.
상기 첨가제로는 분산제 등 이 분야에서 일반적으로 사용되는 것을 들 수 있다. 상기 분산제로는 시판되는 계면 활성제를 이용할 수 있고, 이들은 각각 단독으로 또는 2종 이상을 조합하여 사용할 수 있다. 상기의 계면 활성제는, 예를 들면, 비이온성 계면활성제로서 알킬 폴리옥시에틸렌에테르, 알킬아릴 폴리옥시에틸렌에테르, 폴리옥시에틸렌 폴리옥시프로필렌 공중합체와 같은 에테르형; 글리세린에스테르의 폴리옥시에틸렌에테르, 솔비탄 에스테르의 폴리옥시에틸렌에테르, 솔비 톨 에스테르의 폴리옥시에틸렌에테르 같은 에스테르에테르형; 폴리에틸렌글리콜지방산에스테르, 글리세린에스테르, 솔비탄에스테르, 프로필렌글리콜에스테르, 슈가에스테르, 알킬폴리글루코시드 같은 에스테르형; 지방산알카놀아미드, 폴리옥시에틸렌지방산아미드, 폴리옥시에틸렌알킬아민, 아민 옥사이드 같은 함질소형이 있으며; 고분자계 계면활성제로서 폴리비닐알콜, 폴리비닐피롤리돈, 폴리아크릴산, 폴리아크릴산-말레인산 공중합체, 폴리 12-히드록시스테아린산 등이 있다.The additives include those generally used in this field such as dispersants. Commercially available surfactants can be used as the dispersant, and these can be used alone or in combination of two or more thereof. The surfactant may be, for example, an ether type such as alkyl polyoxyethylene ether, alkylaryl polyoxyethylene ether, polyoxyethylene polyoxypropylene copolymer as a nonionic surfactant; Ester ether types such as polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, and polyoxyethylene ether of sorbitol ester; Ester type such as polyethylene glycol fatty acid ester, glycerin ester, sorbitan ester, propylene glycol ester, sugar ester, alkyl polyglucoside; Nitrogen-containing types such as fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, amine oxides; Polymeric surfactants include polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylic acid-maleic acid copolymers, poly 12-hydroxystearic acid, and the like.
시판되는 상품으로는 하이퍼머(hypermer) KD(Uniqema 제조), AKM 0531(일본유지㈜ 제조), KP(신에쯔 가가꾸 고교㈜ 제조), 폴리플로우 (POLYFLOW)(교에이샤 가가꾸㈜ 제조), 에프톱(EFTOP)(토켐 프로덕츠사 제조), 아사히가드(Asahi guard), 서플론(Surflon)(이상, 아사히 글라스㈜ 제조), 솔스퍼스(SOLSPERSE)(제네까㈜ 제조), EFKA(EFKA 케미칼스사 제조), PB 821(아지노모또㈜ 제조), BYK-184, BYK-185, BYK-2160, Anti-Terra U(BYK사 제조) 등을 들 수 있다. Commercially available products include Hypermer KD (manufactured by Uniqema), AKM 0531 (manufactured by Nippon Yuji Co., Ltd.), KP (manufactured by Shin-Etsu Chemical Co., Ltd.), and polyflow (POLYFLOW) (manufactured by Kyoeisha Kagaku Co., Ltd.). ), EFTOP (manufactured by Tochem Products), Asahi guard, Suflon (above, manufactured by Asahi Glass), SOLSPERSE (manufactured by Geneva), EFKA (EFKA) Chemicals Co., Ltd.), PB 821 (made by Ajinomoto Co., Ltd.), BYK-184, BYK-185, BYK-2160, Anti-Terra U (by BYK Co., Ltd.), etc. are mentioned.
상기 분산제는 유기 비히클 용액 총 중량에 대하여 1~10 중량%로 포함되는 것이 바람직하며, 더욱 바람직하게는 1~5 중량%가 좋다.The dispersant is preferably included in 1 to 10% by weight based on the total weight of the organic vehicle solution, more preferably 1 to 5% by weight.
본 발명에 따른 페이스트는 자전과 공전을 동시에 수행하는 플래너리 믹서를 이용하여 쉽게 제조될 수 있다. 즉, 상기에서 언급된 성분들을 해당 조성비에 따라 플래너리 믹서 용기에 넣고 교반을 실시하여 고형분과 유기 비히클 용액을 적절히 혼합 및 분산키켜 제조 할 수 있다. 이렇게 제조된 페이스트의 점도는 25℃에서 부룩필드(Brookfield) HBDV-III Ultra Rheometer, 스핀들 CPE-52로 측정했을 때, 5rpm에서 20,000~200,000cps이다. 바람직하게는 40,000~100,000cps 범위로 제조되는 것이 좋다.The paste according to the present invention can be easily prepared by using a planetary mixer which simultaneously performs both rotating and revolving. That is, the above-mentioned components may be prepared by mixing and dispersing the solid content and the organic vehicle solution appropriately by putting the above-mentioned components into the planetary mixer container according to the corresponding composition ratio and stirring. The viscosity of the paste thus prepared was 20,000-200,000 cps at 5 rpm as measured by a Brookfield HBDV-III Ultra Rheometer, spindle CPE-52 at 25 ° C. Preferably it is preferably produced in the range of 40,000 ~ 100,000cps.
또한, 본 발명은In addition,
상기 알루미늄 페이스트를 사용하여 후면 전극을 형성하는 공정을 포함하는 것을 특징으로 하는 태양전지의 제조방법을 제공한다.It provides a method of manufacturing a solar cell comprising the step of forming a back electrode using the aluminum paste.
상기 방법에 의하여 제조된 태양전지는 휨이나 전극 층에 알루미늄 기포 및 범프(Bμmp)의 발생이 최소화되어, Isc 및 Voc 값이 향상될 뿐만 아니라 태양전지의 효율도 획기적으로 향상된다.The solar cell manufactured by the above method minimizes warpage and generation of aluminum bubbles and bumps (Bμmp) in the electrode layer, thereby improving Isc and Voc values as well as dramatically improving the efficiency of the solar cell.
이하에서, 실시예를 통하여 본 발명을 보다 상세히 설명한다. 그러나, 하기의 실시예는 본 발명을 더욱 구체적으로 설명하기 위한 것으로서, 본 발명의 범위가 하기의 실시예에 의하여 한정되는 것은 아니다. 하기의 실시예는 본 발명의 범위 내에서 당업자에 의해 적절히 수정, 변경될 수 있다.Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention.
실시예1: 알루미늄 페이스트의 제조Example 1 Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 63 중량%와 D50=2~4㎛인 알루미늄 분말 7 중량%를 넣고(4~6㎛ : 2~4㎛ = 9 : 1(중량비), 알루미늄 분말 총량 = 70 중량%), 하기 표 1의 조성의 글라스 프릿 0.5 중량%, 에틸셀룰로오스를 글리콜 에테르에 녹여 용해시 킨 유기 비히클 용액 29.5 중량%를 순차적으로 첨가 한 후, 자전 및 공전을 동시에 수행하는 믹서를 이용하여 1,000rpm에서 3분간 교반을 실시하여 알루미늄 페이스트를 제조하였다. 63 wt% of aluminum powder having D 50 = 4-6 μm and 7 wt% of aluminum powder having D 50 = 2-4 μm (4-6 μm: 2-4 μm = 9: 1 (weight ratio)), and the total amount of aluminum powder = 70% by weight), 0.5% by weight of glass frit having the composition shown in Table 1, and 29.5% by weight of an organic vehicle solution dissolved by dissolving ethyl cellulose in glycol ether, and then sequentially rotating and rotating. The aluminum paste was prepared by stirring at 1,000 rpm for 3 minutes.
실시예2: 알루미늄 페이스트의 제조Example 2 Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 42 중량%와 D50=2~4㎛인 알루미늄 분말 28 중량%를 넣은(4~6㎛ : 2~4㎛ = 6 : 4(중량비), 알루미늄 분말 총량 = 70 중량%) 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다. 42 weight% of aluminum powder having D 50 = 4-6 μm and 28 weight% of aluminum powder having D 50 = 2-4 μm (4-6 μm: 2-4 μm = 6: 4 (weight ratio)) = 70% by weight) aluminum paste was prepared in the same manner as in Example 1.
실시예3: 알루미늄 페이스트의 제조Example 3 Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 66.5 중량%와 D50=2~4㎛인 알루미늄 분말 3.5 중량%를 넣은(4~6㎛ : 2~4㎛ = 9.5 : 0.5(중량비), 알루미늄 분말 총량 = 70 중량%) 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다. 66.5% by weight of aluminum powder having D 50 = 4-6 µm and 3.5% by weight of aluminum powder having D 50 = 2-4 µm (4-6 µm: 2-4 µm = 9.5: 0.5 (weight ratio)) = 70% by weight) aluminum paste was prepared in the same manner as in Example 1.
실시예4: 알루미늄 페이스트의 제조Example 4 Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 58.5 중량%와 D50=2~4㎛인 알루미늄 분말 6.5 중량%를 넣고(4~6㎛ : 2~4㎛= 9 : 1(중량비), 알루미늄 분말 총량 = 65 중량%), 유기 비히클 용액을 34.5 중량%로 첨가한 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다. 58.5% by weight of aluminum powder having D 50 = 4-6 μm and 6.5% by weight of aluminum powder having D 50 = 2-4 μm (4-6 μm: 2-4 μm = 9: 1 (weight ratio)), and the total amount of aluminum powder = 65% by weight), an aluminum paste was prepared in the same manner as in Example 1 except that the organic vehicle solution was added at 34.5% by weight.
실시예5: 알루미늄 페이스트의 제조Example 5 Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 67.5 중량%와 D50=2~4㎛인 알루미늄 분말 7.5 중량%를 넣고(4~6㎛ : 2~4㎛ = 9 : 1(중량비), 알루미늄 분말 총량 = 75 중량%), 유기 비히클 용액을 24.5 중량%로 첨가한 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다. 67.5 wt% of aluminum powder having D 50 = 4-6 μm and 7.5 wt% of aluminum powder having D 50 = 2-4 μm (4-6 μm: 2-4 μm = 9: 1 (weight ratio)), and the total amount of aluminum powder = 75 wt%), an aluminum paste was prepared in the same manner as in Example 1 except that the organic vehicle solution was added at 24.5 wt%.
비교예1: 알루미늄 페이스트의 제조Comparative Example 1: Preparation of Aluminum Paste
D50=4~6㎛인 알루미늄 분말 35 중량%와 D50=2~4㎛인 알루미늄 분말 35 중량%를 넣고(4~6㎛ : 2~4㎛ = 5 : 5(중량비), 알루미늄 분말 총량 = 70 중량%), 유기 비히클 용액을 29.5 중량%로 첨가한 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다. 35 wt% of aluminum powder having D 50 = 4-6 μm and 35 wt% of aluminum powder having D 50 = 2-4 μm (4-6 μm: 2-4 μm = 5: 5 (weight ratio)), and the total amount of aluminum powder = 70% by weight), an aluminum paste was prepared in the same manner as in Example 1 except that the organic vehicle solution was added at 29.5% by weight.
비교예2: 알루미늄 페이스트의 제조Comparative Example 2: Preparation of Aluminum Paste
D50=2~4㎛인 알루미늄 분말 70 중량%, 유기 비히클 용액을 29.5 중량%로 첨가한 것을 제외하고는 실시예 1과 동일한 방법으로 알루미늄 페이스트를 제조하였다An aluminum paste was prepared in the same manner as in Example 1, except that 70 wt% of aluminum powder having a D 50 = 2˜4 μm and 29.5 wt% of an organic vehicle solution were added.
시험예: 태양전지의 제조 및 특성 테스트Test Example: Manufacturing and Characteristic Test of Solar Cell
156X156mm, 200μm 두께의 단결정 웨이퍼에 표면 텍스쳐링 공정을 수행하여 피라미드 높이가 약 4-6μm로 형성된 후, 웨이퍼의 N-측 상에 SiNx를 코팅하였다. 이어서, 웨이퍼의 후면에 은-페이스트를 이용하여 Bus Bar를 인쇄 한 후 건조시킨 후, 상기 실시예와 비교예에 예시된 페이스트를 250mesh의 스크린 인쇄판을 이용하여 도포하고 건조 시켰다. 도포량은 건조전에 1.5±0.1g이 되도록 인쇄한 후 건조시키고, 전면 SiNx측 상에 은-페이스트를 이용하여 Finger Line을 인쇄하고 건조하였다.A surface texturing process was performed on a 156 × 156 mm, 200 μm thick single crystal wafer to form a pyramid height of about 4-6 μm, followed by coating SiNx on the N-side of the wafer. Subsequently, the Bus Bar was printed on the back surface of the wafer using silver paste, followed by drying. Then, the pastes exemplified in Examples and Comparative Examples were applied and dried using a 250-mesh screen printing plate. The coating amount was printed to be 1.5 ± 0.1 g before drying and dried, and the Finger Line was printed and dried using silver paste on the front SiNx side.
상기 과정을 거친 실리콘 웨이퍼를 적외선 연속 소성로에서 소성영역의 온도가 720~900℃가 되도록 하여 소성하여 태양전지를 제조하였다.The silicon wafer passed through the above process was fired in an infrared continuous firing furnace such that the temperature of the firing region was 720 to 900 ° C. to manufacture a solar cell.
상기 소성공정은 상기 실리콘 웨이퍼를 벨트 로(Belt Furnace) 내로 통과 시키면서 전후면 동시 소성으로 수행될 수도 있다. 이때, 벨트 로(Belt Furnace)는 약 600℃의 Burn-out 구간과 800~950℃ 부근의 Firing 구간을 포함하며, 페이스트 내 유기물을 태워 없앤 후, 전후면 은과 알루미늄을 용융시켜서 전극이 형성되게 한다.The firing process may be performed by simultaneous firing of the front and rear surfaces while passing the silicon wafer into a belt furnace. At this time, the belt furnace includes a burn-out section of about 600 ° C. and a firing section around 800 ° C. to 950 ° C., and burns away the organic material in the paste, and then melts the silver and aluminum on the front and rear surfaces to form an electrode. do.
상기에서 제조된 태양전지의 네모서리를 바닥과 일치시킨 후, 중앙부의 들뜸정도를 측정하여 태양전지의 휘어짐 정도를 평가하였다. 또한, 후면 알루미늄 전극 부위의 범프(bμmp) 및 알루미늄 기포의 발생은 육안으로 관찰하여 개수를 카운트 하였다. 평가 결과는 하기 표 2에 나타내었다.After matching the four corners of the solar cell manufactured above with the bottom, the degree of lifting of the center portion was measured to evaluate the degree of warpage of the solar cell. In addition, the occurrence of bumps (bμmp) and aluminum bubbles in the rear aluminum electrode region was visually observed and the number was counted. The evaluation results are shown in Table 2 below.
태양전지의 효율은 FitTech사의 태양전지 성능 평가 장치인 SCM-1000을 이용하여 평가하고, 그 결과를 하기 표 3에 나타내었다.The efficiency of the solar cell was evaluated using SCM-1000, a solar cell performance evaluation apparatus of FitTech, and the results are shown in Table 3 below.
4~6㎛ : 2~4㎛
(중량비)D 50 =
4 ~ 6㎛: 2 ~ 4㎛
(Weight ratio)
※ Isc = 단락 전류(A)※ Isc = short circuit current (A)
Voc = 개방 전압(V)Voc = open voltage (V)
Rs = Series ResistanceRs = Series Resistance
FF = Fill FactorFF = Fill Factor
실시예 6: 알루미늄 페이스트 인쇄량 조절 Example 6: Adjusting the amount of aluminum paste printing
실시예 1에 의해 제조된 알루미늄 페이스트를 인쇄조건을 변경하여 알루미늄 페이스트의 인쇄량을 1.0g, 1.2g, 1.5g, 1.8g, 2.0g을 인쇄한 후 위의 동일한 방법으로 평가하고 그 결과를 표 4에 나타내었다.After changing the printing conditions of the aluminum paste prepared in Example 1 by printing 1.0g, 1.2g, 1.5g, 1.8g, 2.0g of aluminum paste printing amount and evaluated in the same manner as above and the results are shown in Table 4 Shown in
상기 표 4에 나타난 것과 같이 후면 알루미늄 페이스트의 인쇄량에 따라 효율편차가 크지 않아 상업적 이용측면에서 기존 2g정도 사용하는 알루미늄 페이스트에 비해 적은 사용량으로도 충분한 태양전지 효율을 나타내었다.As shown in Table 4, the efficiency deviation was not large according to the printing amount of the rear aluminum paste, and thus, sufficient efficiency of the solar cell was shown even with a small amount of use compared to the aluminum paste used about 2g in terms of commercial use.
Claims (6)
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| KR1020090097217A KR20110040083A (en) | 2009-10-13 | 2009-10-13 | Aluminium paste for a back electrode of solar cell |
| CN201080037313.4A CN102576578B (en) | 2009-10-13 | 2010-10-13 | For the aluminium paste of back electrode of solar cell |
| PCT/KR2010/006993 WO2011046360A2 (en) | 2009-10-13 | 2010-10-13 | Aluminum paste for back electrode of solar cell |
| TW099134929A TW201133510A (en) | 2009-10-13 | 2010-10-13 | Aluminum paste for back electrode of solar cell |
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| CN103000247A (en) * | 2012-11-10 | 2013-03-27 | 江苏瑞德新能源科技有限公司 | Solar cell backside aluminum paste powder adaptable to high sheet resistance and shallow junction |
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| CN102522141B (en) * | 2011-12-28 | 2013-11-06 | 彩虹集团公司 | Conducting aluminum paste for silicon solar cell and preparation method thereof |
| CN102522142B (en) * | 2011-12-28 | 2013-11-06 | 彩虹集团公司 | Conducting paste for silicon solar cell and preparation method thereof |
| CN103489502B (en) * | 2013-10-18 | 2015-11-18 | 南通天盛新能源科技有限公司 | Be applied to back field aluminum paste of N-type crystalline silicon solar cell and preparation method thereof |
| CN103811100A (en) * | 2014-01-16 | 2014-05-21 | 北京林业大学 | Silicon solar cell back-surface field forming aluminum paste and preparation method thereof |
| CN105405488A (en) * | 2015-11-30 | 2016-03-16 | 无锡帝科电子材料科技有限公司 | Aluminium paste for laser pore-forming partial back contact-passivating emitter crystalline silicon solar cell and preparation method and application thereof |
| US10174210B2 (en) * | 2015-12-15 | 2019-01-08 | National Cheng Kung University | Method of fabricating high-conductivity thick-film aluminum paste |
| CN106448805B (en) * | 2016-09-30 | 2018-01-02 | 江苏瑞德新能源科技有限公司 | A kind of solar energy aluminum conductor slurry and preparation method thereof |
| CN108877988A (en) * | 2018-06-14 | 2018-11-23 | 扬州鑫晶光伏科技有限公司 | High-performance crystal silicon solar back field aluminum paste material and preparation method thereof and crystal silicon solar batteries prepared therefrom |
| CN111129176A (en) * | 2019-12-20 | 2020-05-08 | 浙江爱旭太阳能科技有限公司 | Method for producing a solar cell and solar cell |
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| US6814795B2 (en) * | 2001-11-27 | 2004-11-09 | Ferro Corporation | Hot melt conductor paste composition |
| US7771623B2 (en) * | 2005-06-07 | 2010-08-10 | E.I. du Pont de Nemours and Company Dupont (UK) Limited | Aluminum thick film composition(s), electrode(s), semiconductor device(s) and methods of making thereof |
| KR101031060B1 (en) * | 2005-10-20 | 2011-04-25 | 도요 알루미늄 가부시키가이샤 | Paste composition and solar battery element using the same |
| CN100463229C (en) * | 2006-07-17 | 2009-02-18 | 谭富彬 | Synthesizing silicon solar energy cell back field aluminum conductive size |
| TWI370552B (en) * | 2007-06-08 | 2012-08-11 | Gigastorage Corp | Solar cell |
| JP2009146578A (en) * | 2007-12-11 | 2009-07-02 | Noritake Co Ltd | Solar cell and solar cell aluminum paste |
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| CN103000247A (en) * | 2012-11-10 | 2013-03-27 | 江苏瑞德新能源科技有限公司 | Solar cell backside aluminum paste powder adaptable to high sheet resistance and shallow junction |
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| WO2011046360A3 (en) | 2011-08-25 |
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