WO2013140549A1 - Cellule solaire et son procédé de fabrication - Google Patents

Cellule solaire et son procédé de fabrication Download PDF

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Publication number
WO2013140549A1
WO2013140549A1 PCT/JP2012/057190 JP2012057190W WO2013140549A1 WO 2013140549 A1 WO2013140549 A1 WO 2013140549A1 JP 2012057190 W JP2012057190 W JP 2012057190W WO 2013140549 A1 WO2013140549 A1 WO 2013140549A1
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WIPO (PCT)
Prior art keywords
electrode
paste
solar cell
height
photoelectric conversion
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PCT/JP2012/057190
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English (en)
Japanese (ja)
Inventor
平　茂治
志敦 寺中
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三洋電機株式会社
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Application filed by 三洋電機株式会社 filed Critical 三洋電機株式会社
Priority to PCT/JP2012/057190 priority Critical patent/WO2013140549A1/fr
Publication of WO2013140549A1 publication Critical patent/WO2013140549A1/fr

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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41P—INDEXING SCHEME RELATING TO PRINTING, LINING MACHINES, TYPEWRITERS, AND TO STAMPS
    • B41P2215/00—Screen printing machines
    • B41P2215/50—Screen printing machines for particular purposes
    • 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

Definitions

  • the present invention relates to a solar cell and a manufacturing method thereof.
  • the solar cell includes an electrode on the main surface of the photoelectric conversion unit in order to collect carriers generated by light reception.
  • Such an electrode is required to suppress the resistance of the electrode itself, the contact resistance between the electrode and the photoelectric conversion unit, the contact resistance between the electrode and the wiring material, and the like.
  • Patent Documents 1 and 2 disclose a method for manufacturing a solar cell in which electrodes are formed by repeating screen printing of a conductive paste a plurality of times.
  • the unevenness of the electrode surface can be reduced, for example, the contact resistance between the electrode and the wiring material can be lowered.
  • further improvement in photoelectric conversion efficiency is required.
  • a solar cell includes a photoelectric conversion unit, a binder, and an electrode provided on a main surface of the photoelectric conversion unit, and at least a part of the electrode has a length of 1 mm or more.
  • the variation coefficient of the electrode height over the entire length is 15% or less.
  • a method for manufacturing a solar cell according to one embodiment of the present invention is a method for manufacturing a solar cell including an electrode on a main surface of a photoelectric conversion unit, and is printed by printing a paste for forming an electrode on the main surface. And pressing the at least part of the paste in the height direction to flatten the upper surface of the paste, and then curing the paste.
  • a solar cell having good photoelectric conversion characteristics can be provided.
  • a second object for example, a transparent conductive layer
  • a first object for example, a main surface of a photoelectric conversion unit
  • FIG. 1 is a plan view of a solar cell 10 as an example of an embodiment of the present invention as viewed from the light receiving surface side.
  • FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 and shows a cross section of the solar cell 10 cut in the thickness direction along the direction in which the finger electrodes 21 and 31 extend.
  • the solar cell 10 includes a photoelectric conversion unit 11 that generates carriers by receiving light such as sunlight, a first electrode 20 that is a light-receiving surface electrode provided on the light-receiving surface of the photoelectric conversion unit 11, and photoelectric conversion. And a second electrode 30 that is a back surface electrode provided on the back surface of the portion 11. On the back surface of the solar cell 10, the second electrode 30 can be formed in a larger area than the first electrode 20 because the influence of the light blocking loss on the photoelectric conversion characteristics is less than that of the light receiving surface.
  • the “light-receiving surface” means a main surface on which sunlight mainly enters from the outside of the solar cell 10. For example, more than 50% to 100% of the sunlight incident on the solar cell 10 enters from the light receiving surface side.
  • the “back surface” means a main surface opposite to the light receiving surface. In other words, the surface having the large electrode area among the main surfaces is the back surface.
  • the photoelectric conversion unit 11 includes a substrate made of a semiconductor material such as crystalline silicon (c-Si), gallium arsenide (GaAs), or indium phosphorus (InP).
  • the photoelectric conversion unit 11 is, for example, a translucent conductive material mainly composed of an i-type amorphous silicon layer, a p-type amorphous silicon layer, indium oxide, and the like on a light-receiving surface of an n-type single crystal silicon substrate.
  • a transparent conductive layer made of an oxide (TCO).
  • TCO oxide
  • an i-type amorphous silicon layer, an n-type amorphous silicon layer, and a transparent conductive layer are sequentially provided on the back surface of the n-type single crystal silicon substrate.
  • the photoelectric conversion unit 11 is not limited to this configuration, and various configurations can be adopted as will be described later.
  • the light receiving surface and the back surface of the photoelectric conversion unit 11 have a texture structure (not shown).
  • the texture structure is a surface uneven structure having a height of about 1 ⁇ m to 15 ⁇ m that suppresses surface reflection and increases the light absorption amount of the photoelectric conversion unit 11.
  • the texture structure there is a pyramidal (quadrangular pyramid or quadrangular pyramid-shaped) uneven structure obtained by performing anisotropic etching on the light receiving surface of a substrate made of single crystal silicon having a (100) plane. It can be illustrated.
  • the first electrode 20 includes, for example, a plurality (for example, 50) of finger electrodes 21 and a plurality (for example, two) of bus bar electrodes 22.
  • the finger electrode 21 is a thin line-shaped electrode formed over a wide range on the light receiving surface in order to collect carriers generated by the photoelectric conversion unit 11.
  • the bus bar electrode 22 is an electrode that collects carriers from the finger electrodes 21, and is electrically connected to all the finger electrodes 21.
  • the first electrode 20 two bus bar electrodes 22 are arranged in parallel with each other at a predetermined interval, and a plurality of finger electrodes 21 are arranged so as to intersect with each other.
  • the plurality of finger electrodes 21 are arranged so that a part thereof extends from each of the bus bar electrodes 22 to the edge side of the light receiving surface and the remaining part connects the two bus bar electrodes 22.
  • the second electrode 30 has the same electrode arrangement as that of the first electrode 20 and includes a plurality (for example, 250) of finger electrodes 31 and a plurality (for example, two) of bus bar electrodes 32.
  • the first electrode 20 and the second electrode 30 are both preferably formed using a conductive paste described later, and include an insulating binder and a conductive filler as electrode materials.
  • the electrode material may contain a small amount of an additive such as a filler dispersant.
  • the electrode material and composition may be changed between the finger electrode and the bus bar electrode, and between the first electrode 20 and the second electrode 30, but in this embodiment, the finger electrodes 21 and 31 and the bus bar electrodes 22 and 32 are It shall be comprised with the same material and the same composition.
  • the width (average value) of the finger electrode 21 is not particularly limited, but is preferably 30 ⁇ m to 150 ⁇ m from the viewpoint of reducing light shielding loss.
  • the width may be narrowed as the distance from the bus bar electrode 22 increases.
  • the width of the finest details is preferably 30 ⁇ m to 80 ⁇ m.
  • the width (average value) of the bus bar electrode 22 is preferably 0.5 mm to 1.5 mm, for example.
  • the width of the finger electrode 31 is preferably larger than that of the finger electrode 21, and is set to 60 ⁇ m to 250 ⁇ m, for example.
  • the height (average value) of the first electrode 20 is not particularly limited, but is preferably 20 ⁇ m to 140 ⁇ m, more preferably 30 ⁇ m to 110 ⁇ m, and particularly preferably 40 ⁇ m to 90 ⁇ m from the viewpoint of reducing resistance loss.
  • the height of the bus bar electrode 22 may be higher than that of the finger electrode 21, but in this embodiment, the average height of the finger electrode 21 and the bus bar electrode 22 is substantially equal.
  • the “substantially equivalent” includes a state that can be regarded as substantially equivalent, for example, a case where the difference in average values is ⁇ 5% or less (the same applies hereinafter).
  • the height of the first electrode 20 is “height h 20 ”
  • the height of the finger electrode 21 is “height h 21 ”
  • the height (average value) of the second electrode 30 is also not particularly limited. However, since the electrode area can be made larger than that of the first electrode 20, it can be made lower than that of the first electrode 20 from the viewpoint of reducing the electrode material. Is preferred. Specifically, it is preferably 5 ⁇ m to 70 ⁇ m, more preferably 10 ⁇ m to 60 ⁇ m, and particularly preferably 15 ⁇ m to 50 ⁇ m.
  • the height of the bus bar electrode 32 may be higher than that of the finger electrode 31 as in the case of the first electrode 20, but in this embodiment, the average height of the finger electrode 31 and the bus bar electrode 32 is substantially equal. It is.
  • the height of the second electrode 30 is “height h 30 ”
  • the height of the finger electrode 31 is “height h 31 ”
  • the height h 20 (the same applies to the height h 30 ) is measured by cross-sectional observation using a scanning electron microscope (SEM), and is measured from the uppermost surface of the photoelectric conversion unit 11 (for example, the convex portion of the texture structure). This is the length to the top surface of one electrode 20.
  • the height h 20 is measured for a cross section obtained by cutting the finger electrode 21 along its longitudinal direction.
  • the coefficient of variation (referred to as “CV 30 ”) is 15% or less. That is, in the solar cell 10, the upper surfaces 23 and 33 of the first electrode 20 and the second electrode 30 are flat and have less unevenness.
  • CV 20 (same for CV 30 ) is a value obtained by dividing the standard deviation of the height h 20 measured over a length of 1 mm or more of the first electrode 20 by the average value of the height h 20. . As CV 20 is smaller, the variation in height h 20 is smaller and the flatness of the upper surface 23 of the first electrode 20 is higher.
  • the standard deviation can be obtained using Microsoft's Excel STDEV function in the above-mentioned range.
  • the coefficient of variation (referred to as “CV 21 ”) of the height h 21 of the finger electrode 21 is such that CV 21 is 15% or less over a length of 1 mm or more along the longitudinal direction.
  • CV 21 is preferably 12% or less, particularly preferably 8% or less.
  • the coefficient of variation (referred to as “CV 22 ”) of the height h 22 of the bus bar electrode 22 is substantially equal to, for example, CV 21 . That is, in the first electrode 20, the upper surfaces 24 and 25 of the finger electrode 21 and the bus bar electrode 22 are both flat and uneven.
  • the finger electrode 21 and the bus bar electrode 22 preferably have CV 21 and CV 22 within the above-mentioned range over their entire length. Furthermore, it is preferable that CV 21 and CV 22 are within the above range in more than half of the plurality of finger electrodes 21 and the plurality of bus bar electrodes 22. In particular, it is preferable CV 22 CV 21 and all of the bus bar electrodes 22 of all the finger electrodes 21 is within the above range. That is, CV 20 is preferably 15% or less over the entire first electrode 20, more preferably 12% or less, and particularly preferably 8% or less.
  • the CV 30 of the second electrode 30 is preferably 15% or less, more preferably 12% or less, and particularly preferably 8% or less over the entire second electrode 30.
  • the coefficient of variation (referred to as “CV 31 ”) of the height h 31 of the finger electrode 31 and the coefficient of variation (referred to as “CV 32 ”) of the height h 32 of the bus bar electrode 32 are CV 31 , CV over the entire length. 32 is 15% or less, preferably 12% or less, particularly preferably 8% or less.
  • CV 21 and CV 22 may be different from each other.
  • the CV 22 may be smaller than the CV 21 . That is, the upper surface 25 of the bus bar electrode 22 may be flatter than the upper surface 24 of the finger electrode 21. By flattening the upper surface 25 to reduce the unevenness, for example, connectivity with a wiring material attached in the modularization is improved.
  • FIG. 3 sectional drawing of the solar cell 10x which is a modification of the solar cell 10 is shown. Similar to the solar cell 10, the solar cell 10 x includes a first electrode 20 x and a second electrode 30 x. On the other hand, in the solar cell 10x, a metal film 31x such as silver (Ag) is provided instead of the finger electrode 31. The metal film 31x is formed in substantially the entire region on the back surface of the photoelectric conversion unit 11 (for example, 95% or more on the transparent conductive layer).
  • the bus bar electrode 32x is formed on the metal film 31x. As with the bus bar electrode 32, the bus bar electrode 32x has a height variation coefficient of 15% or less over a length of 1 mm or more along the longitudinal direction thereof.
  • the height of the finger electrode 21x and the bus bar electrode 22x varies greatly, the upper surface has large irregularities, and the coefficient of variation in height exceeds 15%. That is, in the solar cell 10x, the variation coefficient of the height of the bus bar electrode 32x (second electrode 30x) is smaller than the variation coefficient of the height of the finger electrode 21x and the bus bar electrode 22x (first electrode 20x). The flatness of the electrodes is different between 20x and the second electrode 30x.
  • the second electrode 30 x including the metal film 31 x may be provided instead of the second electrode 30.
  • FIG. 4 is a diagram for explaining the principle of the screen printing method.
  • 5 and 6 are diagrams showing an electrode forming process of the solar cell 10.
  • 7 and 8 are diagrams showing another example of the electrode forming process of the solar cell 10.
  • 5 to 8 are schematic views of FIG. 5 to 8, the paste 50 printed on the light receiving surface of the photoelectric conversion unit 11 to form the first electrode 20 is “paste 50a”, and the paste 50 printed on the back surface to form the second electrode 30 is “ This is referred to as “paste 50b”.
  • paste 50b the paste 50 printed on the light receiving surface of the photoelectric conversion unit 11 to form the first electrode 20
  • the paste 50 printed on the back surface to form the second electrode 30 is “ This is referred to as “paste 50b”.
  • a description will be given by attaching a and b to the related elements of the pastes 50a and 50b.
  • the photoelectric conversion unit 11 is manufactured by a known method.
  • the paste 50a to be the first electrode 20 and the paste 50b to be the second electrode 30 are printed on the main surface.
  • the electrode printing method is not particularly limited as long as the paste 50 containing the electrode material (the binder and the filler) can be printed on the main surface.
  • a stencil printing method offset printing method, screen printing method
  • a paste jet method can be used.
  • the printing order of the pastes 50a and 50b is not limited, the following description will be made assuming that the paste 50b is printed first.
  • the paste 50b is preferably printed by a screen printing method from the viewpoint of productivity and accuracy.
  • a screen printing method plate making and squeegee 44 are used.
  • a screen plate 40 illustrated in FIG. 4 or a metal mask plate (not shown) can be used.
  • the screen printing method using the screen plate 40 is illustrated.
  • the screen plate 40 b having the opening 43 b corresponding to the shape of the second electrode 30 and the squeegee 44 are used on the back surface of the photoelectric conversion unit 11.
  • the paste 50b is transferred to the substrate.
  • the paste 50b is preferably printed at substantially the same height according to the shape of the finger electrode 31 and the bus bar electrode 32. That is, it is preferable that the paste 50b transferred onto the back surface has substantially the same height over the entire length of each electrode.
  • the screen printing process of the paste 50b is performed, for example, by placing the photoelectric conversion unit 11 on the flat table 51 with the back surface facing the screen plate 40b. More specifically, the paste 50 is placed on the screen plate 40b in which the opening 43b is formed only on the portion to which the paste 50b is to be transferred, and the squeegee 44 is slid to fill the opening 50 with the paste 50. Subsequently, when the portion of the screen plate 40b through which the squeegee 44 passes is separated from the back surface, the paste 50 is discharged from the opening 43b and transferred onto the back surface. In this embodiment, off-contact printing is described, but on-contact printing may be applied.
  • the screen plate 40 has a mesh 41 stretched on a frame (not shown).
  • the mesh 41 is a woven fabric or the like that transmits the paste 50, and the mesh 41 is provided with a mask material 42 corresponding to a region on the main surface where the paste 50 is not desired to be applied. That is, the screen plate 40 allows the paste 50 to pass through only the opening 43 which is a portion of the mesh 41 that is not masked by the mask material 42.
  • the material, wire diameter, number of meshes, opening, opening rate, etc. of the mesh 41 are selected according to the width, height, etc. of the second electrode 30 to be formed.
  • the mesh 41 is made of, for example, a resin fiber such as polyester or a metal wire such as stainless steel.
  • the wire diameter of the mesh 41 is selected according to the height of the second electrode 30 and the like.
  • the number of meshes is selected according to the strength of the mesh 41 and the definition of the second electrode 30.
  • the opening is selected according to the particle size of the filler contained in the paste 50, and is generally preferably at least twice the particle size.
  • the opening rate is selected according to the height and the width of the second electrode 30.
  • a photosensitive emulsion is usually used.
  • the emulsion is selected according to the resolution, exposure sensitivity, and the like.
  • a diazo or stilbazolium material is used.
  • a metal foil can be used.
  • the emulsion is coated on the mesh 41 and becomes a mask material 42 through an ultraviolet exposure process and an unexposed part removal process.
  • the thickness (plate thickness) of the screen plate 40 can be easily adjusted by increasing or decreasing the thickness (emulsion thickness) of the mask material 42.
  • the electrode height can be increased as the plate thickness increases.
  • the squeegee 44 is made of a material suitable for spreading the paste 50 on the screen plate 40.
  • the squeegee 44 is preferably composed of an elastic body having solvent resistance.
  • urethane rubber or the like is suitable.
  • the shape of the squeegee 44 is not particularly limited, but a flat squeegee is suitable.
  • the paste 50 is a fluid fluid paste.
  • a heat-curing type conductive paste in which a binder and a filler, which are electrode materials, and a solvent are mixed is suitable.
  • a binder for example, an epoxy resin, a urethane resin, a urea resin, an acrylic resin, an imide resin, a thermosetting resin such as a phenol resin, or a modified or mixture thereof can be used.
  • epoxy resins are preferred.
  • metal particles such as silver (Ag), copper (Cu), nickel (Ni), aluminum (Al), silver-coated copper, silver-coated aluminum, carbon, or a mixture thereof can be used. . Of these, silver particles are preferred.
  • solvent for example, alcohol-based, glycol ether-based, hydrocarbon-based organic solvents, or mixed solvents thereof can be used.
  • a squeegee angle As main parameters for determining printing conditions, a squeegee angle, a squeegee speed, a squeegee printing pressure (also simply referred to as a printing pressure), a clearance that is a distance between the screen plate 40 and the photoelectric conversion unit 11, and the like.
  • the squeegee angle is preferably about 50 ° to 80 °
  • the printing pressure is preferably about 2 to 6 kgf / cm 2 .
  • the paste 50b printed on the back surface is pressed in the height direction, and the upper surface 53b of the paste 50b is flattened.
  • a pressing device is placed on the paste 50b printed on the back surface and the upper surface 53b is pressed.
  • a flattening screen plate 45 that is a plate making without an opening and a squeegee 44 used in the screen printing step can be used.
  • the flattening screen plate 45 is composed of the same mesh 41 and mask material 42 as the screen plate 40. However, the flattening screen plate 45 does not have an opening corresponding to the electrode shape.
  • the entire mesh 41 is masked by the mask material 42.
  • the surface of the mask material 42 that contacts the paste 50b is a flat surface without unevenness, and preferably has no unevenness of 5 ⁇ m or more.
  • the squeegee 44 is slid on the surface opposite to the surface that contacts the paste 50b of the screen plate 45 for flattening.
  • the paste 50b is compressed and the upper surface 53b is flattened.
  • the angle and speed of the squeegee 44, the pressing force by the squeegee 44 (the force by which the squeegee 44 pushes the flattening screen plate 45), etc. are not particularly limited, and can be set similarly to the screen printing step. Normally, the higher the pressing force by the squeegee 44, the stronger the paste 50b is compressed, the lower the height of the paste 50b, and the higher the flatness of the upper surface 53b.
  • the solvent contained in the paste 50b Before proceeding to the flattening step, it is preferable to remove the solvent contained in the paste 50b as long as the upper surface 53b can be flattened.
  • the solvent can be removed by heat treatment or the like.
  • the heat treatment hereinafter referred to as “temporary drying process” is performed at 150 ° C. for 5 minutes to eliminate the tack (adhesiveness) of the paste 50b and the paste with the printing pressure in the printing process of the paste 50a. 50b is crushed and adjusted to an amount of solvent that can be plastically deformed.
  • the curing reaction of the binder resin may proceed as long as the upper surface 53b can be flattened.
  • the paste 50b whose upper surface 53b is flattened is subjected to a heat treatment (hereinafter referred to as “main drying treatment”) at a temperature higher than the temporary drying treatment for a long time (for example, 200 ° C. ⁇ 60 minutes).
  • the paste 50b can be cured by removing the solvent and heat-curing the binder.
  • the main drying process of the paste 50b is preferably performed together with the main drying process of the paste 50a from the viewpoint of reducing process costs.
  • the paste 50a is printed on the light receiving surface, and the upper surface 53a of the paste 50a is flattened using the flattening screen plate 45 similarly to the paste 50b, and then the pastes 50a and 50b are simultaneously subjected to the main drying process. It is. In this case, if the paste 50a is printed on the table 51 as described later, the paste 50b may be further flattened.
  • the first electrode 20 having a CV 20 of 15% or less and the second electrode 30 having a CV 30 of 15% or less can be produced.
  • the screen printing of the paste 50a can be performed in the same manner as the screen printing of the paste 50b. However, since height h 20 > height h 30 , printing is performed using the screen plate 40a having a plate thickness larger than that of the screen plate 40b used for printing the paste 50a. In the screen plate 40a, it is possible to print a paste 50a in which the mask material 42a is thicker than the mask material 42b and higher than the paste 50b. Further, since the width of the finger electrode 21 ⁇ the width of the finger electrode 31, the opening width of the opening 43a is narrower than the opening width of the opening 43b, and a paste 50a having a smaller width than the paste 50b can be printed.
  • the paste 50b can be flattened by a method different from the above method.
  • the photoelectric conversion unit 11 is inverted, and the photoelectric conversion unit 11 is arranged on the table 51 with the light receiving surface facing the screen plate 40a side. To do.
  • the paste 50a is printed on the light receiving surface while pressing the paste 50b printed on the back surface onto the table 51 to flatten the upper surface 53b.
  • the paste 50b is strongly pressed in the height direction by the printing pressure of the paste 50a in the screen printing process, and the upper surface 53b is flattened.
  • the table 51 is, for example, a table having a flat surface without unevenness (preferably having no unevenness of 5 ⁇ m or more). Such a flat surface is larger than the main surface of the photoelectric conversion unit 11, and it is preferable that the entire main surface can be uniformly supported and pressed.
  • the printing pressure in the screen printing of the paste 50a affects not only the printing characteristics of the paste 50a but also the flattening of the paste 50b. Normally, as the printing pressure increases, the pressing force against the paste 50b increases and the paste 50b is strongly compressed, the height of the paste 50b decreases, and the flatness of the upper surface 53b improves.
  • the intermediate body 12 in which the paste 50 b having the flat upper surface 53 b is formed on the back surface of the photoelectric conversion unit 11 and the paste 50 a is printed on the light receiving surface can be obtained. Since the intermediate body 12 has not undergone the flattening process of the paste 50a, large irregularities exist on the upper surface 53a.
  • the solvent in the pastes 50a and 50b can be removed, and the binder can be subjected to a thermosetting reaction to cure the pastes 50a and 50b.
  • the CV 30 of the second electrode 30 is 15% or less, and the CV 20 of the first electrode 20 exceeds 15%. That is, the second electrode 30 is flatter than the first electrode 20.
  • a flattening step of the paste 50a can be further provided.
  • a flattening screen plate 45 may be used, or the photoelectric conversion unit 11 may be reversed and the paste 50 a may be pressed against the table 51.
  • the main drying process is performed after the flattening step of the paste 50a or in a state where pressing by the press plate 52 is continued.
  • the solvents in the pastes 50a and 50b can be removed, and the pastes 50a and 50b can be cured by thermosetting the binder.
  • the first electrode 20 having a flat upper surface 25 and CV 20 of 15% or less and the second electrode 30 having a flat upper surface 35 and CV 30 of 15% or less are manufactured. be able to.
  • the paste for forming the second electrode 30x by limiting the printing order of each paste for forming the first electrode 20x and the second electrode 30x. is there. Specifically, after the paste for forming the bus bar electrode 32x is printed on the metal film 31x and planarized, the paste for forming the first electrode 20x is printed on the light receiving surface. Thereby, the sulfidation and oxidation of the metal film 31x in the heat treatment step of the first electrode 20x can be prevented, and the contact resistance between the metal film 31x and the bus bar electrode 32x can be kept low.
  • FIG. 9A shows measured values of the height along the longitudinal direction of the finger electrode 81 of the conventional battery 60
  • FIGS. 9B and 9C show the measured value along the longitudinal direction of the finger electrode 31 of the solar cell 10.
  • the measured value of the height h 31 is shown.
  • the horizontal axis represents the electrode length
  • the vertical axis represents the electrode height.
  • FIG. 10 shows a cross-sectional view of the conventional battery 60.
  • the solar cell 10 and the conventional battery 60 are provided with the same photoelectric conversion unit 11 and differ only in electrode form. Similar to the solar battery 10, the conventional battery 60 includes the finger electrode 71, the first electrode 70 including the bus bar electrode 72, and the second electrode 80 including the finger electrode 81 and the bus bar electrode 82. , 50b is different from the solar cell 10 in that it has not undergone the flattening process.
  • Figure 9 (b) to the finger electrode 31 measurements is shown a height h 31 (hereinafter referred to as “finger electrodes 31A”), and the finger electrode measured value of the height h 31 in FIG. 9 (c) are shown 31 (hereinafter referred to as “finger electrode 31B”) is obtained by flattening the upper surface 34 by pressing paste 50b printed at substantially the same height with different pressures.
  • the finger electrode 31A was formed through a low-pressure (0.5 MPa) flattening step, and the finger electrode 31B was formed through a high-pressure (1.0 MPa) flattening step.
  • the finger electrodes 31A and 31B both have a small variation in the height h 31 and the CV 31 over a length of 1 mm or more is 15% or less.
  • the average value of the height h 31 was 33.1 ⁇ m, and the CV 31 was 11.5%.
  • the average value of the height h 31 was 30.3 ⁇ m, and the CV 31 was 7.2%. That found the pressing force is higher in the flattening process, CV 31 becomes paste 50b is compressed strongly height h 31 low is reduced.
  • the finger electrode 81 had an average height value of 26.0 ⁇ m and a height variation coefficient of 17.9%. That is, the finger electrode 81 has a height variation coefficient of more than 15%, and the top surface has large irregularities compared to the finger electrodes 31A and 31B, and the height varies.
  • the finger electrode on the light-receiving surface side having substantially the same dimensions as the finger electrodes 31A, 31B, and 81, and the light reception, respectively.
  • Bus bar electrodes on the surface side and the back surface side were provided.
  • the wiring material was attached to the bus-bar electrode of each solar cell, and the output characteristic was evaluated. The evaluation results are shown as a ratio to the conventional battery 60 (curve factor of solar cells 10A and 10B / curve factor of conventional battery 60).
  • the solar cells 10A and 10B having a high flatness on the electrode upper surface have lower output resistance than the conventional battery 60 having a lower flatness on the electrode upper surface and have good output characteristics.
  • the output characteristics improve as the flatness increases.
  • the photoelectric conversion unit 11 is less likely to be damaged when the wiring member is thermocompression bonded to the bus bar electrode. This tendency becomes remarkable when the coefficient of variation is about 15%.
  • the paste printed on the main surface of the photoelectric conversion unit 11 is pressed and compressed, so that the unevenness on the upper surface of the paste is reduced and a flattened electrode is formed.
  • Such an electrode has a variation coefficient of electrode height of 15% or less over a length of 1 mm or more, preferably over the entire length.
  • the electrode material is strongly compressed and the fillers are in strong contact with each other, and a good conductive path is obtained. Can be formed. For this reason, the resistance of the electrode itself can be reduced.
  • the adhesion between the electrode and the photoelectric conversion unit 11 can be improved, and the contact resistance between the electrode and the photoelectric conversion unit 11 can be reduced.
  • the manufacturing cost can be reduced by reducing the amount of conductive paste used while maintaining low resistance loss. Further, the finger electrode can be further thinned while maintaining a low resistance loss, thereby reducing a light shielding loss.
  • the connectivity with the wiring material attached when modularizing is improved.
  • the contact area between the electrode and the wiring material is increased, the adhesion between the electrode and the wiring material is improved, and the contact resistance between the two is also reduced.
  • the wiring material is thermocompression bonded to the electrode, the influence of the stress generated at that time can be reduced.
  • the unevenness of the upper surface of the electrode is large, pressure is likely to be applied to the convex portion, and stress concentrates on a part of the photoelectric conversion portion 11, and damage such as cracks or cracks may occur in the photoelectric conversion portion 11.
  • the flatness of the upper surface of the electrode is high, the stress applied to the photoelectric conversion unit 11 can be dispersed, and damage to the photoelectric conversion unit 11 can be suppressed.
  • the solar cell 10 exhibits good photoelectric conversion characteristics due to, for example, a synergistic effect thereof.
  • the photoelectric conversion unit 11 includes an n-type amorphous silicon layer 101 and an n-type amorphous silicon film 102 formed on the light-receiving surface side of an n-type single crystal silicon substrate 100.
  • a structure having an n-type region composed of the n-type amorphous silicon layer 107, the transparent conductive layer 108, and an insulating layer 111 provided between the p-type region and the n-type region may be employed.
  • an electrode is provided only on the back side of n-type single crystal silicon substrate 100.
  • the electrodes include a p-side collector electrode 109 formed on the p-type region and an n-side collector electrode 110 formed on the n-type region.
  • the photoelectric conversion unit 11 includes a p-type polycrystalline silicon substrate 120, an n-type diffusion layer 121 formed on the surface side of the p-type polycrystalline silicon substrate 120, and a p-type polycrystalline.
  • a structure having an aluminum metal film 122 formed on the back surface of the silicon substrate 120 may be used.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Photovoltaic Devices (AREA)

Abstract

Cellule solaire (10) munie d'une unité de conversion photoélectrique (11) ; ainsi que d'une première électrode (20) et d'une seconde électrode (30) contenant un liant et une charge et disposées sur les surfaces principales de l'unité de conversion photoélectrique (11), respectivement. Au moins une partie de la première électrode (20) et au moins une partie de la seconde électrode (30) ont un coefficient de variation de hauteur d'électrode de 15 % ou moins pour une longueur de 1 mm ou plus. La première électrode (20) et la seconde électrode (30) sont fabriquées par impression de portions de pâte (50a, 50b) sur les surfaces principales respectives, lesdites portions de pâte formant les électrodes respectives, par aplatissement des surfaces supérieures (53a, 53b) des portions de pâte (50a, 50b) par pressage, dans le sens de la hauteur, d'au moins une partie de chacune des portions de pâte imprimées (50a, 50b), enfin, par durcissement des portions de pâte (50a, 50b).
PCT/JP2012/057190 2012-03-21 2012-03-21 Cellule solaire et son procédé de fabrication WO2013140549A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10763435B2 (en) 2016-09-27 2020-09-01 Teknologian Tutkimuskeskus Vtt Oy Layered apparatus and its manufacturing method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07335921A (ja) * 1994-06-07 1995-12-22 Canon Inc 光起電力素子の集電電極作製方法
JPH11103084A (ja) * 1997-09-26 1999-04-13 Sanyo Electric Co Ltd 太陽電池素子の製造方法及び太陽電池素子
JP2008529264A (ja) * 2005-01-20 2008-07-31 コミツサリア タ レネルジー アトミーク 半導体デバイスのメタライゼーション方法
WO2011004758A1 (fr) * 2009-07-09 2011-01-13 株式会社シンク・ラボラトリー Procédé de fabrication de batterie solaire et batterie solaire
JP2011061109A (ja) * 2009-09-14 2011-03-24 Shin-Etsu Chemical Co Ltd 太陽電池素子の製造方法及び太陽電池素子
JP2011249663A (ja) * 2010-05-28 2011-12-08 Sanyo Electric Co Ltd 太陽電池モジュール及びその製造方法
JP2012005988A (ja) * 2010-06-28 2012-01-12 Dainippon Screen Mfg Co Ltd パターン形成方法およびパターン形成装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07335921A (ja) * 1994-06-07 1995-12-22 Canon Inc 光起電力素子の集電電極作製方法
JPH11103084A (ja) * 1997-09-26 1999-04-13 Sanyo Electric Co Ltd 太陽電池素子の製造方法及び太陽電池素子
JP2008529264A (ja) * 2005-01-20 2008-07-31 コミツサリア タ レネルジー アトミーク 半導体デバイスのメタライゼーション方法
WO2011004758A1 (fr) * 2009-07-09 2011-01-13 株式会社シンク・ラボラトリー Procédé de fabrication de batterie solaire et batterie solaire
JP2011061109A (ja) * 2009-09-14 2011-03-24 Shin-Etsu Chemical Co Ltd 太陽電池素子の製造方法及び太陽電池素子
JP2011249663A (ja) * 2010-05-28 2011-12-08 Sanyo Electric Co Ltd 太陽電池モジュール及びその製造方法
JP2012005988A (ja) * 2010-06-28 2012-01-12 Dainippon Screen Mfg Co Ltd パターン形成方法およびパターン形成装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10763435B2 (en) 2016-09-27 2020-09-01 Teknologian Tutkimuskeskus Vtt Oy Layered apparatus and its manufacturing method

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