CN102610666A - MWT (metal wrap through) back-contact solar cell, preparation method and module thereof - Google Patents
MWT (metal wrap through) back-contact solar cell, preparation method and module thereof Download PDFInfo
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- 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
- H01L31/022441—Electrode arrangements specially adapted for back-contact solar cells
- H01L31/02245—Electrode arrangements specially adapted for back-contact solar cells for metallisation wrap-through [MWT] type solar cells
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- 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
- Y02E10/547—Monocrystalline silicon PV cells
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Abstract
The invention provides an MWT (metal wrap through) back-contact solar cell, a preparation method and a module thereof, belonging to the field of photovoltaic techniques. The MWT back-contact solar cell comprises a first conductive type area, a second conductive type area, an auxiliary gate electrode, a through hole, a main gate electrode and a second electrode, wherein the first conductive type area is arranged on the back surface of a cell substrate, the second conductive type area is arranged on the front surface of the cell substrate, and the contact between the main gate electrode and the cell substrate is set as a non-ohmic contact, or an insulating layer is also arranged between the main gate electrode and the cell substrate so as to realize the electrical isolation of positive and negative electrodes of the cell. Therefore, the solar cell is simple in preparation method and high in conversion efficiency, a step of forming an isolation channel is omitted, and the breakage rate of a corresponding cell preparation module is low.
Description
Technical field
The invention belongs to the photovoltaic technology field, be specifically related to metal around wearing type (Metal Wrap Through, MWT) back of the body contact solar cell, preparation method and assembly thereof.
Background technology
Because the finiteness that conventional energy resource is supplied with and the increase of environmental protection pressure; Many in the world countries have started the upsurge of development and use solar energy and regenerative resource at present; Solar utilization technique has obtained fast development, wherein utilizes utilization that semi-conductive photovoltaic effect changes solar energy into electric energy more and more widely.And solar cell is exactly that wherein general to be used to solar energy converting be the device of electric energy.In practical application, generally be as basic applying unit with the battery component that forms by a plurality of solar cells series connection (being connected in series) with the interconnector welding.
Normally, solar cell comprises pn knot, and the inside photogenerated current that produces because of shining upon in its cell substrate (like monocrystalline silicon) need be collected and it is compiled and draw through the electrode of battery.Solar cell comprises the front and the back side, is defined as the front of solar cell when wherein battery operated by the one side that sunlight shone, and the one side opposite with this front is defined as the back side.Routinely, be formed for the main grid electrode that the secondary gate electrode (or inferior grid line) of collected current and being used to compiles the electric current of secondary gate electrode in its front; On its back side, form backplate with projected current.
Along with the development of solar cell technology, proposed in recent years main grid electrode with battery front side place the cell substrate back side (with backplate on one side) back of the body contact-type solar cell.Than conventional solar cell, the solar cell of back of the body contact-type has the following advantages at least: the firstth, and, the solar cell of back of the body contact-type has higher conversion efficiency because of having eliminated front main grid electrode pair irradiation of sunlight obstruction loss (the shading area reduces); The secondth,, main grid electrode and backplate all are formed at (on the back side) on the same surface, therefore be equipped to battery component more easily between a plurality of batteries, cost of manufacture is lower; The 3rd is, having avoided needs the situation of solder interconnections bar simultaneously at front and back, helps the automated production of assembly; The 4th is, the main grid electrode places the back side to make battery have outward appearance more uniformly, the battery component of prepared formation (attractive in appearance is important for some application, and for example BIPV is used) more attractive in appearance relatively.
Wherein, metal is a kind of in the back of the body contact solar cell around the type of wearing, and in this battery, forms a plurality of through holes in the cell substrate, is connected with the main grid electrode electricity that is arranged on cell backside through the secondary gate electrode of through hole with the front.
Metal for prior art shown in Figure 1 is carried on the back the structural representation of contact solar cell around wearing type.As shown in Figure 1,10 for being formed at the positive secondary gate electrode of cell substrate, and main grid electrode 9 is formed at the cell substrate back side, and secondary gate electrode 10 electrically connects through through hole with main grid electrode 9, and backplate 6 also is formed at the cell substrate back side.Backplate 6 is used to draw the electric current that first conductiving type semiconductor area 7 of cell substrate is produced, and secondary gate electrode 10 and main grid electrode 9 are used to draw the electric current that second conductiving type semiconductor area 8 of cell substrate is produced.
As shown in Figure 1; For avoiding backplate 6 and main grid electrode 9 short circuits to cause the battery plus-negative plate short circuit; Usually when forming second conductivity type regions 8 of second conduction type, reserve overleaf first conduction type first conductivity type regions 7 expose the zone, form backplate 6 with composition above that.When diffusing, doping forms second conductiving type semiconductor area 8, need extra mask composition like this, and after diffusion, again mask is removed complex technical process.Thereby be unfavorable for reducing the cost of solar cell.And in other prior art, the isolation between backplate 6 and the main grid electrode 9 can also realize that groove can be isolated perhaps accurate wet etching isolation through laser and realized through the method that forms groove.The performing step of groove can increase the preparation cost of solar cell, reduces the conversion efficiency of battery, and particularly the laser isolation possibly cause follow-up assembly to prepare fragment rate increase in the process, reduces rate of finished products.
Therefore, to the defective of prior art, need the research and development metal that a kind of technology is simple, conversion efficiency is high, preparation cost is low, the assembly fragment rate is low around wearing the contact of the type back of the body solar cell, preparation method and assembly thereof.
Summary of the invention
The technical problem that the present invention will solve is to reduce the preparation cost of back of the body contact solar cell, the technological process of simplification back of the body contact solar cell and the rate of finished products that improves solar cell.
For solving above technical problem, provide a kind of metal around wearing type back of the body contact solar cell according to one side of the present invention, it comprises:
Cell substrate; Comprise first conductivity type regions and second conductivity type regions; Said second conductivity type regions and first conductivity type regions lay respectively at the front and back of said cell substrate, and said second conductivity type regions and first conductivity type regions form PN junction;
The secondary gate electrode that composition is formed on said second conductivity type regions and electrically connects with said second conductivity type regions;
Pass the through hole of said cell substrate, the conduction type of the inner surface of said through hole is first conduction type;
Be connected with said secondary gate electrode based on said through hole, composition is formed at the main grid electrode on said first conductivity type regions; And
Second electrode that composition is formed on said first conductivity type regions and electrically connects with said first conductivity type regions;
Wherein, said main grid electrode is non-ohmic contact with contacting of said cell substrate, also is provided with insulating barrier between perhaps said main grid electrode and the said cell substrate.
Carry on the back an embodiment of contact solar cell according to metal provided by the invention around wearing type; Wherein, Said main grid electrode comprises back portion and around wearing part; Said back portion is arranged on said first conductivity type regions, saidly is arranged in the said through hole and extends on second conductivity type regions with secondary gate electrode and electrically connect around wearing part.
Around the another embodiment that wears type back of the body contact solar cell, wherein, said main grid electrode is to be that 0 slurry printing and sintering form basically through frit content according to metal provided by the invention.
Preferably, said main grid electrode is silver-colored material.
Preferably, said solar cell also comprises the connection electrode that is used to connect said main grid electrode and said secondary gate electrode that is formed on said cell substrate front.
Preferably, said main grid electrode and said connection electrode all form through low-temperature setting.
Said main grid electrode is arranged to continuous or discontinuous.
Preferably, be provided with the hollow out zone in the said main grid electrode.
Preferably, also comprise the antireflection layer that is formed on said second conductivity type regions.
Around an embodiment again who wears type back of the body contact solar cell, wherein, said first conductivity type regions is the p semiconductor regions according to metal provided by the invention, and said second conductivity type regions is the n semiconductor regions.
Preferably, said second electrode is an aluminium material, and said second electrode and said first conductivity type regions form ohmic contact.
Preferably, said solar cell comprises that also composition is formed at the third electrode on said first conductivity type regions, and said third electrode and said second electrode electrically connect.
Preferably, said third electrode and said main grid electrode print formation synchronously.
Carry on the back another embodiment of contact solar cell according to metal provided by the invention around wearing type; Wherein, Said insulating barrier is through forming in composition printing on the said through-hole inner surface and on the back side of said first conductivity type regions, and the marginal portion of said insulating barrier extends beyond the contact area of main grid electrode and cell substrate.
Around the another embodiment that wears type back of the body contact solar cell, wherein, said main grid electrode forms through printing of silver slurry and sintering according to metal provided by the invention, and said insulating barrier is that said silver slurry forms in said sintering process with said cell substrate.
Preferably, said silver slurry is for containing the silver slurry of frit, and said insulating barrier is the glass medium layer that forms in the sintering process.
According to another aspect of the present invention, provide more than one any metals of addressing around the preparation method who wears type back of the body contact solar cell, it comprises step:
(1) cell substrate with first conductivity type regions is provided;
(2) said cell substrate is carried out making herbs into wool and cleaning;
(3) doping of second conduction type being carried out in the front of said cell substrate is to form second conductivity type regions;
(4) etching is to remove the doped region of second conduction type except that said front;
(5) the deposition antireflection layer in the front of said cell substrate; And
(6) composition forms the main grid electrode and second electrode on said first conductivity type regions, and composition forms secondary gate electrode in the front of said cell substrate;
Wherein, also be included in location formation through hole and the step of removing the formed damage of drilling in the said cell substrate between any two steps in step (1) to (6).
According to a preparation method's provided by the invention embodiment, the step of location formation through hole is positioned between step (1) and (2) in said cell substrate, and the step of removing the formed damage of drilling realizes through the making herbs into wool in the step (2).
According to preparation method's provided by the invention another embodiment, the step of location formation through hole and the formed damage of removal drilling is positioned between step (5) and (6) in said cell substrate.
Embodiment again according to preparation method provided by the invention in said step (6), also comprises: on said first conductivity type regions, form third electrode, said third electrode is used to realize the electric connection of said second electrode and interconnector.
Preferably, in said step (6), also comprise: on said second conductivity type regions, form connection electrode, said connection electrode is used to connect said main grid electrode and said secondary gate electrode.
Wherein, said step (6) may further comprise the steps:
(6a) composition printing third electrode on the back side of said cell substrate;
(6b) composition prints said second electrode;
(6c) composition prints said secondary gate electrode;
(6d) sintering;
(6e) with low temperature curing type condensate slurry composition printing main grid electrode and connection electrode; And
(6f) solidify.
Preferably, the peak temperature of said sintering is 800 ℃ basically, and the temperature range of said curing is 100 ℃-650 ℃.
Preferably; In said step (6); Form said second electrode, third electrode, secondary gate electrode through printing and sintering; And through frit content is that 0 slurry printing and sintering form said main grid electrode basically, is sintered between said main grid electrode and the said cell substrate and forms non-ohmic contact.
According to another embodiment of preparation method provided by the invention, printing earlier forms said main grid electrode, republishes and forms said secondary gate electrode.
Preferably, said third electrode and said main grid electrode are all silver-colored material, and said third electrode and said main grid electrode print formation synchronously.
Another embodiment according to preparation method provided by the invention; In said step (6); Form said main grid electrode through printing of silver slurry and sintering; And in said sintering process, at the insulating barrier that is formed for realizing electrical isolation between said main grid electrode and the said cell substrate between said main grid electrode and the said cell substrate.
Preferably, said silver slurry is for containing the silver slurry of frit, and said insulating barrier is the glass medium layer.
According to a preparation method's provided by the invention embodiment again, in step (6), be formed for realizing the insulating barrier of the electrical isolation between said main grid electrode and the said cell substrate in printing on the said cell substrate.
Preferably, in said step (4), said etching is a wet etching.
Wherein, form said through hole through chemical wet etching, mechanical punching, laser drilling or electronic beam drilling.
According to another aspect of the present invention; A kind of solar module is provided; Said solar module comprises any solar cell that the above reaches, and connects through interconnector between the said solar cell, and carries out lamination and frame up back formation with prebasal plate, backboard and the layer that is sealing adhesive.
Technique effect of the present invention is, through between main grid electrode and cell substrate, forming non-ohmic contact or insulating barrier, to realize the electrical isolation of said battery plus-negative plate.Therefore, do not need to form isolation channel through method etchings such as laser in addition; And second conductivity type regions that is formed on first conductivity type regions only gets final product positive formation of cell substrate.Therefore, solar cell preparation method simply and because of saving the step that forms isolation channel makes the fragment rate of cell preparation assembly low.
Description of drawings
From the following detailed description that combines accompanying drawing, will make above and other objects of the present invention and advantage clear more fully.
Fig. 1 is the structural representation of the MWT back of the body contact solar cell of prior art;
Fig. 2 is the partial schematic diagram according to the structure of the MWT back of the body contact solar cell of the embodiment of the invention;
Fig. 3 is partial cross section's structural representation that the MWT back of the body embodiment illustrated in fig. 2 contacts solar cell;
Fig. 4 is the structure for amplifying sketch map in the indicated zone of A among Fig. 3, and wherein Fig. 4 (a) is an instance wherein, and Fig. 4 (b) is another instance wherein;
Fig. 5 is the preparation method's process sketch map according to the MWT back of the body contact solar cell of first embodiment provided by the invention;
Fig. 6 to Figure 11 changes sketch map according to preparation method's structure of process shown in Figure 5;
Figure 12 is the preparation method's process sketch map according to the MWT back of the body contact solar cell of second embodiment provided by the invention;
Figure 13 is the preparation method's process sketch map according to the MWT back of the body contact solar cell of the 3rd embodiment provided by the invention;
Figure 14 to Figure 19 changes sketch map according to preparation method's structure of process shown in Figure 13;
Figure 20 is the partial schematic diagram according to the structure of the MWT back of the body contact solar cell of further embodiment of this invention;
Figure 21 is preparation method's process embodiment sketch map of the electrode of solar cell shown in Figure 20.
Embodiment
What introduce below is some among a plurality of possibility embodiment of the present invention, aims to provide basic understanding of the present invention, is not intended to confirm key of the present invention or conclusive key element or limits claimed scope.Understand easily, according to technical scheme of the present invention, do not changing under the connotation of the present invention, but one of ordinary skill in the art can propose other implementation of mutual alternative.Therefore, following embodiment and accompanying drawing only are the exemplary illustrations to technical scheme of the present invention, and should not be regarded as qualification or the restriction to technical scheme of the present invention that all perhaps be regarded as of the present invention.
In the accompanying drawings, for the sake of clarity, might amplify the thickness of layer or the area in zone, but should not be considered to the proportionate relationship that strictness has reflected physical dimension as sketch map.And in the accompanying drawings, same or analogous key element adopts identical label to represent.
" front of solar cell " among the present invention is meant the one side that receives solar light irradiation when battery operated, i.e. light receiving surface, and " back side of solar cell " among the present invention is meant and " front of solar cell " opposite one side.
Shown in Figure 2 is the partial schematic diagram that contacts the structure of solar cell according to the MWT back of the body of the embodiment of the invention.Shown in Figure 3 is partial cross section's structural representation that the MWT back of the body embodiment illustrated in fig. 2 contacts solar cell.In conjunction with Fig. 2 and shown in Figure 3 solar cell of the present invention is elaborated as follows.
The MWT back of the body contact solar cell 100 of this embodiment forms based on cell substrate 110.In this embodiment, select p type monocrystalline silicon piece as cell substrate, like this, in this embodiment, first conductivity type regions is the p type, the second conductivity type regions n type.The material type of cell substrate is not restrictive, and for example cell substrate 110 can also be the solar cell basis material of polycrystalline silicon material or other types.The concrete shape of the cell substrate 110 of solar cell is not limited by illustrated embodiment yet.As shown in Figure 3; In this embodiment; Comprise p semiconductor regions 112 that substrate itself provides and the n semiconductor regions of being mixed and form in the front of cell substrate 110 111 in the cell substrate 110; Particularly, can mix to form p semiconductor regions 112 and n semiconductor regions 111 through the front of the p type monocrystalline silicon piece of cell substrate 110 being carried out the n type.The thickness range of n semiconductor regions 111 can be 0.1 micron to 1 micron.P semiconductor regions 112 and the n semiconductor regions 111 common pn knots that form solar cell; The electric current of n semiconductor regions is drawn through the secondary gate electrode 130 in the front of solar cell and the main grid electrode 150 at the back side, and the electric current of p semiconductor regions 112 is drawn through the backplate 160 of solar cell.
Consult Fig. 3, form some secondary gate electrodes 130 on the front 120 of solar cell, secondary gate electrode 130 is used to collect the electric current that the front 120 of solar cell is produced.Routinely, laterally arrange between the secondary gate electrode 130, spacing between the secondary gate electrode 130 and secondary gate electrode 130 width own are not limited by the present invention.Normally, secondary gate electrode 130 is to form with the silk screen printing of silver slurry, and in this embodiment, secondary gate electrode 130 is formed in positive n semiconductor regions 111 surfaces and goes up and electrically connect with the n semiconductor regions, thereby can collect its electric current.
For forming MWT back of the body contact solar cell, on the substrate of secondary gate electrode 130 corresponding positions, can form the through hole 140 that several penetrate cell substrate 110 (also promptly passing n semiconductor regions 111 and p semiconductor regions 112).On every or some secondary gate electrode 130, separated by a distance after can and 150 interconnections of main grid electrode, main grid electrode 150 can compile and draw the electric current of the battery front side that secondary gate electrode 130 collects effectively.In this invention; In the junction of secondary gate electrode 130 with corresponding main grid electrode 150; Through hole 140 is set, and the conduction type of the cell substrate of the inner surface of through hole 140 is p type conduction type, main grid electrode 150 is drawn from the back side 190 of cell substrate around reach through hole 140.Through hole 140 can pass through methods such as chemical wet etching, mechanical punching, laser drilling, electronic beam drilling and form.
Consult Fig. 2 and Fig. 3; Main grid electrode 150 can be starched silk screen printing or the steel mesh printing forms through silver, and many main grid electrodes 150 are parallel to be formed at the back side 190 of solar cell by row, and main grid electrode 150 comprises back portion 150a and around wearing part 150b; The two all is to form through integrated printing; Wherein, back portion 150a is arranged on the p semiconductor regions 112, is arranged on the n semiconductor regions 111 around wearing part 150b; Preferably; Be arranged in the said through hole and extend on the n semiconductor regions 111 around wearing part 150b, thereby realize be connected (structure roughly as shown in Figure 3) with secondary gate electrode 130, can avoid the electrode material of secondary gate electrode 130 to get in the through hole 140 like this and with the p semiconductor regions 111 formation ohmic contact of through hole 140.Every main grid electrode 150 can be continuously; Also can be for discrete, those skilled in the art can select according to concrete designing requirement, in this embodiment; Every main grid electrode 150 is discontinuous (as shown in Figure 2), also promptly is made up of a plurality of block main grid electrodes.In addition, also form second electrode on the back side of solar cell, promptly backplate 160.According to the basic principle of solar cell, between backplate 160 and the main grid electrode 150 (being directly electrically connection between positive pole and the negative pole of pn knot) that needs electrical isolation.Therefore, through through hole 140 cause cell substrate 110 the back side main grid electrode 150 need with the cell substrate electrical isolation.
Shown in Figure 4 is the structure for amplifying sketch map in the indicated zone of A among Fig. 3, and wherein Fig. 4 (a) is an instance wherein, and Fig. 4 (b) is another instance wherein.Main grid electrode 150 can pass through dual mode with the electrical isolation (also being the electrical isolation of the positive and negative electrode of solar cell) of cell substrate 110 to be realized:
First kind; Shown in Fig. 4 (a); To form in the instance of main grid electrode 150 through silver slurry silk screen printing and sintering, main grid electrode 150 is non-ohmic contact at the inner surface place of through hole 140 with contacting of cell substrate 110 (for example the p semiconductor regions 112), and is same; Main grid electrode 150 also is non-ohmic contact with the contacting of (for example the p semiconductor regions 112) at the back side of cell substrate 110; Like this, the electric current that p semiconductor regions 112 is produced can not flow to main grid electrode 150, thereby can not form the loop with the electric current that n semiconductor regions 111 is produced; Preferably, to be chosen as glass (glass) material content be 0 silver paste basically for silver slurry.
Second kind; Shown in Fig. 4 (b); Realize electrical isolation through insulating barrier 151 is set between main grid electrode 150 and cell substrate 110, in this example, main grid electrode 150 forms with slurry silk screen printing and sintering; The inner surface that insulating barrier 151 can be formed at through hole 140 through printing is or/and on the backside surface of p semiconductor regions 112; Thereby when forming main grid electrode 150 with silver slurry silk screen printing and sintering, the silver slurry does not directly contact with cell substrate 110, and insulating barrier 151 can be nonconducting nonmetal oxide material; In addition, in sintering process, insulating barrier 151 also can spontaneously form insulating barrier 151 through the contact area in silver slurry and cell substrate 110 (for example the p semiconductor regions 112); Preferably; The silver slurry is chosen as the slurry that contains glass (glass) material, and the mass percent scope of frit in the silver slurry is 1%-80%, thereby can be implemented in the sintering process; The frit composition can concentrate on cell substrate 110 forms thin layer with the contact-making surface place of slurry glass medium layer, also is insulating barrier 151.
In above first kind of instance; For as much as possible guaranteeing to form non-ohmic contact between main grid electrode 150 and the cell substrate 110; Realize the electrical isolation between the positive and negative electrode; Preferably, the scope of the resistivity of cell substrate 110 (for example p type doping content) is 0.1ohm.cm-20ohm.cm.
Continue as shown in Figure 2; Preferably, some hollow outs zone 152 is set on main grid electrode 150, thereby can reduces the contact area of main grid electrode metal and silicon (also being p semiconductor regions 112) greatly; Reduce the recombination rate of metal and silicon effectively, and then improve the conversion efficiency of solar cell.Simultaneously, vacancy section is set also can significantly reduces main grid electrode metal consumption (for example silver paste), thus the cost of reduction solar cell.Hollow out zone 152 is set to square shape or toroidal in this embodiment, but its concrete shape is not receive embodiment of the invention restriction, for example can also other are irregularly shaped etc. for triangle etc.Position and the shape size of hollow out zone 152 on the main grid electrode is principle with the electric connection that does not influence metal in main grid electrode and the through hole.
Continue as shown in Figure 3ly, backplate 160 is formed directly on the backside surface of p semiconductor regions 112 and with p semiconductor regions 112 and electrically connects, thereby can the electric current of p semiconductor regions 112 be drawn through the backplate 160 of solar cell.Preferably; For reducing the contact resistance of p semiconductor regions 112 and backplate 160, as shown in Figure 3, backplate 160 selects IIIA bunch metallic element as backplate material (for example aluminium or aluminium alloy) particularly; Thereby in the process of sintering; Aluminium element can diffuse into surf zone, the realization of p semiconductor regions 112 it is further carried out the doping of p type, thereby forms the zone 180 of relative high-dopant concentration, zone 180 is easy to and backplate 160 formation ohmic contact; And the reduction contact resistance, reach the effect of back surface field simultaneously; Most of back electrode material still is retained in the back side and has formed aluminum back electric field, also is backplate 160.Need to prove; The zone 180 and the p semiconductor regions 112 of high-dopant concentration normally do not have obvious boundary as shown in Figure 3; This is because with backplate during as doped source; According to the characteristics of diffusing, doping, doped chemical aluminium diffuses in the p semiconductor regions 112 with the concentration gradient mode.
Continue as shown in Figure 3ly, in another specific embodiment, solar cell 100 also comprises and is deposited on cell substrate 110 antireflection layer 113 positive, on the n semiconductor regions 112.Antireflection layer 113 can be materials such as silicon nitride, and its concrete thickness range can be the 70-90 nanometer.Through antireflection layer 113 is set, can further effectively reduces the reflectivity of solar battery surface, thereby improve the conversion efficiency of solar cell.Need to prove that in the solar cell 100 of above embodiment, because the isolation between the positive and negative electrode need not form isolation channel or accurate wet etching formation isolation channel through laser, with respect to the solar cell of prior art, its conversion efficiency is higher relatively.
Consult shown in Figure 2; In this embodiment; Solar cell 100 also comprises the third electrode 161 that is arranged on the back of solar cell; It mainly is used in preparation the medium that is connected between battery and the battery being provided during assembly, is used for improving the connection performance of battery and interconnector, helps improving the connection reliability that solar cell is interconnected to form solar module.The quantity of third electrode 161 can be according to the characteristic decision of bonding strength requirement and the interconnector that uses, and it is not restrictive.Preferably; Third electrode 161 is selected and main grid electrode 150 identical materials; For example silver-colored, thus in silk screen printing or steel mesh printing process formation main grid electrode 150, composition forms synchronously; Help further simplifying the step of preparation process of battery, thereby reduce the cost of manufacture of solar cell.
Below will specify preparation method's process of Fig. 2, MWT embodiment illustrated in fig. 3 back of the body contact solar cell.
Shown in Figure 5 is the preparation method's process sketch map that contacts solar cell according to the MWT back of the body of first embodiment provided by the invention.Fig. 6 is extremely shown in Figure 11 to be to change sketch map according to preparation method's structure of process shown in Figure 5.Below in conjunction with Fig. 5, Fig. 6 to Figure 11 preparation method's process of this embodiment is described, also the concrete structure of this MWT back of the body contact solar cell is done schematically explanation simultaneously.
At first, step S 10, and the cell substrate with first conduction type is provided.As shown in Figure 6, in this embodiment, solar cell is based on cell substrate 110 preparations and forms, and selects p type monocrystalline silicon as cell substrate 110 (also promptly first conduction type is the p type).Particularly, the electrical resistivity range of p type monocrystalline silicon can be 0.1ohmcm-20ohmcm, but it is not limited by present embodiment.The front 120 of cell substrate 110 is by solar light irradiation, the back side 190 of cell substrate 110 when battery operated not by solar light irradiation.
Further, step S20, the location forms through hole in cell substrate.As shown in Figure 7, on cell substrate 110, form several through holes 140, through hole 140 penetrates into the back side of cell substrate from the front of cell substrate.Methods such as through hole 140 can chemical wet etching, mechanical punching, laser drilling, electronic beam drilling form, and normally, select laser drilling to form.The concrete shape of through hole 140 is relevant with selected manufacturing process, for example, when selecting laser drilling, forms columniform through hole as shown in Figure 7.Through hole 140 is mainly used in from the back side and draws the main grid electrode, and its concrete shape and size are not restrictive.For example, through hole can select to be roughly cylindrical or the truncated cone-shaped hole, and its diameter range is about 10 microns to 1000 microns.Through hole 140 is to be formed to desire composition and form on the position of secondary gate electrode, through the position of positioning through hole 140, and can locating pair gate electrode 130 and the position of the junction of corresponding main grid electrode 150.
Further, step S30 carries out making herbs into wool and cleaning to cell substrate, and removes the formed damage of drilling.The detailed process of process for etching and cleaning is basic identical with conventional technology in this step.Through making herbs into wool, for example can form matte (not shown), thereby help improving the conversion efficiency of battery on the cell substrate surface such as Pyramid; Through hole 140 is also by formed matte roughening simultaneously, and this helps improving the reliability that slurry is filled.
Further, step S40 mainly carries out the doping of second conduction type to the front of cell substrate.As shown in Figure 8, in this embodiment, n type doping (also being second conduction type) is carried out in the front of cell substrate 110; Preferably, can be one group with two cell substrate, back-to-back contact; Place diffusion furnace to carry out the single face diffusion then, help improving output like this.In this preferred embodiment; When mixed in the cell substrate front; Can mix to the side and the back side of cell substrate 110 inevitably, for example the inner surface of through hole 140 will be doped, and therefore can form the n semiconductor regions 111a on cell substrate as shown in Figure 8 110 surfaces.Particularly, can select methods such as diffusing, doping, ion implantation doping to mix.
Further, step S50, wet etching is removed the doped region of second conduction type on the side and the back side.Such as step S40 description, main when mixed in the front of cell substrate, can be mixed simultaneously in the place outside the n in the front semiconductor regions 111 (for example side) inevitably.As shown in Figure 9; Can cell substrate 110 be floated in the etching liquid; Wherein face up; Thereby the front of cell substrate 110 can not be etched, and removing other overseas n type zones (the for example hole wall of through hole, side of substrate and/or the back side) of positive n type semiconductor region will be etched away, thereby form the n semiconductor regions 111 on the front.Etching liquid can be the various solution that can carry out etching to silicon, and its particular type and composition do not receive the restriction of the embodiment of the invention.Need to prove in addition, in this embodiment, when cell substrate 110 floats in the etching liquid; Because the capillary effect of liquid level, in the positive edge of cell substrate 110, it can contact with etching liquid and be etched; Therefore can be in the n semiconductor regions of the edge in the front of cell substrate 110 by etching (not shown) partly; The corner, edge that also is n semiconductor regions 111 will be by etching partly, and still, its zone that is etched is limited.
Need to prove, can remove the phosphorosilicate glass layer that forms on cell substrate 110 surfaces in the doping process usually in the wet etching process simultaneously.
Further, step S60, deposition antireflection layer in the front of cell substrate.Shown in figure 10, being deposited on the n semiconductor regions 111 is the antireflection layer 113 of substrate face, and it can pass through methods such as PECVD, APCVD and form, and antireflection layer 113 can be chosen as materials such as silicon nitride, and its concrete thickness range can be the 70-90 nanometer.Through antireflection layer 113 is set, can effectively improve the conversion efficiency of solar cell.
Further, step S70 forms main grid electrode and backplate in said cell substrate back-patterned, and composition forms secondary gate electrode in said cell substrate front.Shown in figure 11, in this embodiment, can select to form secondary gate electrode 130, main grid electrode 150 and backplate 160 with technology composition such as conventional silk screen printing or steel mesh printing and sintering.Wherein, because the materials variances between secondary gate electrode 130, main grid electrode 150 and the backplate 160, it also is the pattern step formation through different silk screen printings or steel mesh printing usually.Preferably, form main grid electrode 150 and third electrode 161 (this moment, first kind of silver-colored slurry can be filled through hole 140) with first kind of silver slurry (for example frit content is 0 silver slurry basically) printing simultaneously; And then with aluminium paste silk screen printing backplate 160; And then with the secondary gate electrode 130 of second kind of silver slurry (for example containing frit) printing formation, secondary gate electrode 130 directly is connected around wearing part 150b with main grid electrode 150, contact thereby make main grid electrode 150 form good electricity with secondary gate electrode 130; And second kind of silver slurry entering hole 140 having avoided being used to form secondary gate electrode 130 contacts (the silver slurry that forms secondary gate electrode might might form ohmic contact with the p semiconductor regions behind sintering) with the p semiconductor regions; Can unify sintering at last forms.Therefore in this preferred embodiment, main grid electrode 150 can form with third electrode 160 simultaneously, helps simplifying technology like this, thereby reduces manufacturing cost.
In addition; Preferably; When silk screen printing forms the main grid electrode, pattern that can also be through half tone is set, when printing forms main grid electrode 150, forming some hollow outs zone 152 (as shown in Figure 2) simultaneously, thus can reduce the contact area of main grid electrode metal and silicon (also being p semiconductor regions 112) greatly; Reduce the compound of metal and silicon effectively, and then improve the conversion efficiency of solar cell.Simultaneously, vacancy section is set also can significantly reduces main grid electrode metal consumption (for example silver paste), thus the cost of reduction solar cell.Position and the shape size of hollow out zone 152 on the main grid electrode followed the principle that is connected that does not influence metal in main grid electrode and the through hole.
For realizing the electrical isolation of main grid electrode 150 and cell substrate 110, in this step S70, can realize through dual mode:
First kind of mode; Shown in Fig. 4 (a); To form in the process of main grid electrode 150 through silver slurry silk screen printing and sintering; Main grid electrode 150 employed first kind of silver slurry are that frit content is 0 silver slurry basically, are sintered between main grid electrode 150 and the cell substrate 110 (for example the p semiconductor regions 112) and connect non-ohmic contact;
The second way shown in Fig. 4 (b), will form in the process of main grid electrode 150 through silver slurry silk screen printing and sintering; In this example, the silver slurry is chosen as the slurry that contains glass (glass) material, and the mass percent scope in the silver slurry of frit is 1%-80%; Thereby can be implemented in the sintering process; Frit concentrates on the contact-making surface place of cell substrate 110 and slurry, thereby forms the glass medium layer of thin layer, also is insulating barrier 151; This insulating barrier 151 is formed between cell substrate 110 and the main grid electrode 150, thereby can realize the basic insulation isolation between main grid electrode 150 and the cell substrate 110.
Need to prove that in the silver slurry, comprise function phase, bonding phase and carrier mutually, bonding is generally frit mutually, the main component of frit is generally SiO
2, PbO, B
2O
3Deng inorganic oxide, it can bond together the silver powder particles of function phase, and conductive silver layer and silicon chip surface are combined securely.The mechanism of action of frit is: in solar cell and conductive silver paste high-temperature sintering process, the frit of inorganic oxide fusing is also corroded silica-based thin antireflective coating and is formed window, and with silicon face firm attached to.Therefore, silver atoms and silicon atom mutually form silver-colored silicon alloy after the melting by a certain percentage under high temperature sintering, thus can make the silver formed silver electrode of slurry and silica-based between form ohmic contact.In above-mentioned first kind of mode; When main grid electrode 150 employed first kind of silver slurry frit content are 0 basically; The formed main grid electrode 150 of silver slurry will can not form ohmic contact with cell substrate, and make between main grid electrode 150 and its cell substrate that is directly contacted and keep electrical isolation.
Further need to prove, among the present invention, in the silver slurry " frit content is 0 basically " not merely to be defined as the mass percentage content of frit definitely be 0 situation; Those skilled in the art are to be understood that; In forming process not under the situation of the silvery silicon alloy of type of formation, frit content is 0 can comprise the situation that has overgauge basically, for example at main grid electrode 150; When the mass percentage content of frit is (0%+0.5%); Or add the function that the frit additive does not possess said frit owing to can not form ohmic contact, frit content is understood that to be 0 basically.
Also need to prove, form in secondary gate electrode 130, main grid electrode 150, the backplate 160 employed slurries, can also comprise the alloying element that is mixed in printing.For example, other metallic element that mixes in the silver slurry forms alloy silver electrode, and other metallic element that mixes in the aluminium paste forms aluminum alloy anode.
So far, MWT back of the body contact solar cell embodiment illustrated in fig. 3 basically forms.
Shown in Figure 12 is the preparation method's process sketch map that contacts solar cell according to the MWT back of the body of second embodiment provided by the invention.Contrast Figure 12 and Fig. 5, the preparation method's of the preparation method of second embodiment and first embodiment difference only is step S65, step S65 is the electrical isolation that is used for realizing main grid electrode 150 and cell substrate 110, forms the structure of the instance shown in Fig. 4 (b).In this embodiment, be different from the mode of the spontaneous formation insulating barrier 151 of sintering among first embodiment, through step S65 composition formation separately in addition.
In step S65, composition forms insulating barrier 151 on the cell substrate of desire formation main grid electrode.Particularly; Insulating barrier 151 can be formed on the backside surface of inner surface and p semiconductor regions 112 of through hole 140 through the printing composition; Thereby in step S70; When forming main grid electrode 150 with silk screen printing of silver slurry and sintering, the silver slurry directly contact with cell substrate 110, thus realization main grid electrode 150 and cell substrate 110 between electrical isolation.Preferably; The marginal portion of insulating barrier 151 extends beyond main grid electrode 150 and contact areas cell substrate (for example the p semiconductor regions 112) that desire forms, and prevents main grid electrode 150 direct contact of part and cell substrate (for example the p semiconductor regions 112) on the edge of.The thickness range of insulating barrier 151 can be 1 micron-50 microns.
In preparation method's process shown in Figure 12, other process is basic and Fig. 5 is basic identical, gives unnecessary details no longer one by one at this.
Shown in Figure 13 is the preparation method's process sketch map that contacts solar cell according to the MWT back of the body of the 3rd embodiment provided by the invention.Than preparation method's process of first embodiment shown in Figure 5, its main difference is that through hole forms the process sequence variation of step.Figure 14 is extremely shown in Figure 19 to be to change sketch map according to preparation method's structure of process shown in Figure 13.Further specify preparation method's process of this embodiment below in conjunction with Figure 13, Figure 14 to Figure 19.
At first, step S11 provides the cell substrate with first conductivity type regions.Shown in figure 14, structure and Fig. 6 are consistent, and in this embodiment, step S11 is identical with the step S10 of first embodiment, repeats no more at this.
Further, step S21 carries out making herbs into wool and cleaning to cell substrate.
Further, step S31 mainly carries out the doping of second conduction type to the front of cell substrate.Shown in figure 15, in this embodiment, the step S40 of the step S31 and first embodiment is basic identical, repeats no more at this.
Further, step S41, wet etching is removed the doped region of second conduction type on the side and the back side.Shown in figure 16, in this embodiment, the step S50 of the step S41 and first embodiment is basic identical, repeats no more at this.
Further, step S51, deposition antireflection layer in the front of cell substrate.Shown in figure 17, the antireflection layer 113 of positive deposition on the n semiconductor regions 111, it can pass through methods such as PECVD, APCVD and form, and antireflection layer 113 can be chosen as materials such as silicon nitride, and its concrete thickness range can be the 70-90 nanometer.
Further, step S61, the location forms through hole in said cell substrate, and removes the formed damage of drilling.
Further, step S71 forms main grid electrode and backplate in said cell substrate back-patterned, and composition forms secondary gate electrode in said cell substrate front.Shown in figure 19; Structure and Figure 11 are consistent, and in this embodiment, step S71 is identical with the step S70 of first embodiment; Main grid electrode 150 can be realized through the dual mode of corresponding description among the step S70 equally with the electrical isolation of cell substrate 110, repeat no more at this.
So far, MWT back of the body contact solar cell embodiment illustrated in fig. 3 basically forms.
Need to prove that complex chart 5 is with embodiment illustrated in fig. 12, those skilled in the art are according between any two steps that can the step that through hole forms step and removes the formed damage of drilling be placed before the preparation electrode.
Need to prove, in another embodiment, also can between step S61 and step S71, increase the step S65 in embodiment illustrated in fig. 12, to realize the electrical isolation of main grid electrode 150 and cell substrate 110.
Shown in Figure 20 is partial schematic diagram according to the structure of the MWT of further embodiment of this invention back of the body contact solar cell, in conjunction with referring to Fig. 2.In this embodiment, be that above-described first kind of mode realizes the electrical isolation between the positive and negative electrode of solar cell, also be not have dielectric layer between main grid electrode 150 and the cell substrate 110, but directly form non-ohmic contact between the two.But when directly forming non-ohmic contact, wherein, when using the silver slurry that does not contain glass paste, can there be the relatively poor problem of adhesive force of main grid electrode 150 in this silver slurry after sintering forms main grid electrode 150.Therefore; In this embodiment; When directly forming non-ohmic contact; Also can adopt the method for the alternative existing high temperature of method of low-temperature setting to form main grid electrode 150, preferably adopt the slurry (for example silver slurry) that contains resinous material to form main grid electrode 150, thereby guarantee the adhesive force between main grid electrode 150 and the cell substrate.But, because the slurry of resinous material and the slurry that is used to form secondary gate electrode etc. high temperature sintering simultaneously because high temperature sintering can change to the chemical characteristic of resinous material, thereby does not reach the technique effect that guarantees adhesive force.Therefore, in this figure embodiment, first high temperature sintering second electrode 160, third electrode 161 and secondary gate electrode 130, low-temperature setting forms main grid electrode 150 again.Form again under the situation of main grid electrode 150 at the secondary gate electrode 130 of above formation earlier; For the slurry that guarantees secondary gate electrode does not get in the through hole; Secondary gate electrode is far away relatively from through hole; Connection reliability between secondary gate electrode and the main grid electrode is existing problems further; Therefore, on the front of cell substrate 110, increase be used to connect the main grid electrode around the connection electrode 170 of wearing part 150b and secondary gate electrode 130, thereby when solution adhesive force problem, can avoid the connection reliability problem between main grid electrode 150 and the secondary gate electrode 130 simultaneously.
Compare solar cell embodiment illustrated in fig. 3 and solar cell embodiment illustrated in fig. 20; Its main difference is the structure of electrode; Therefore; Preparation method's process of the solar cell of embodiment shown in Figure 20 is than preparation method's process of Fig. 5, Figure 12 or solar cell shown in Figure 13, and its main difference part is step S70 or step S71.Therefore, the something in common of its preparation method is given unnecessary details no longer one by one, below further the formation step of electrode is elaborated.
Shown in Figure 21 is preparation method's process embodiment sketch map of the electrode of solar cell shown in Figure 20.After preparation forms Figure 10 or structure shown in Figure 180, further carry out following steps to form the electrode of solar cell.
At first, step S710, composition printing third electrode on the back side of said cell substrate (as shown in Figure 2 161).In this embodiment, forming third electrode 161 employed slurries is the silver slurry that contains frit.
Further, step S720, composition printed back electrode (shown in figure 20 160).In this embodiment, backplate 160 can adopt the aluminium paste printing to form aluminum back electric field.
Further, step S730, composition print secondary gate electrode (shown in figure 20 130).In this embodiment, the slurry that forms secondary gate electrode 130 adopts the slurry (the for example used silver slurry of the positive secondary gate electrode of crystal-silicon solar cell) that contains frit.When the secondary gate electrode of printing; Form ohmic contact for avoiding the employed slurry of secondary gate electrode to get in the through hole 140 contacting with cell substrate; The patterned line segment form of secondary gate electrode; Also be that secondary gate electrode is being disconnected (in embodiment illustrated in fig. 2, secondary gate electrode can be formed on the main grid electrode of through hole continuously) near the through hole, the distance between secondary gate electrode and the through hole 140 keeps certain limit so that the employed slurry of secondary gate electrode is difficult to get into through hole 140 when printing.
Further, step S740, high temperature sintering.In this embodiment, identical with the electrode sintering process of routine, the peak temperature of sintering is basically about 800 ℃.Therefore, third electrode 161, backplate 160 and secondary gate electrode 131 form
Further, step S750 is with low temperature curing type condensate slurry composition printing main grid electrode (shown in figure 20 150) and connection electrode (shown in figure 20 170).In this embodiment; Because secondary gate electrode breaks off in the through hole, be difficult to form the main grid electrode 150 of auxiliary connection gate electrode through filling paste in through hole 140, also be the main grid electrode be difficult to be guaranteed with the reliability that is connected of secondary gate electrode 130 around wearing part 150b; Therefore; Need printing to form connection electrode 170, connection electrode 170 be patterned on the main grid electrode around wearing between part 150b and the secondary gate electrode 130, can connect main grid electrode and secondary gate electrode preferably.In addition; For guaranteeing the adhesive force between adhesive force, connection electrode (170) and the cell substrate between main grid electrode 150 and the cell substrate; The two has all selected low temperature curing type condensate slurry (the silver slurry that for example contains resinous material); This slurry can (100-650 ℃) be realized resinae or other type organic polymer body completion curing in the slurry under the low temperature drying condition, form the electrode with certain machinery, mechanical property of conduction, and this electrode and firm the combining of silicon face; Have good adhesive force, for the silver conduction passage is provided simultaneously.In the LOTES process, silver does not form alloy with silicon, can not form ohmic contact.
Further, step S760, low-temperature setting.In this embodiment; Can under hot conditions, lose the characteristic that it improves adhesive force owing to contain the slurry of resinous material; Therefore must adopt relatively low temperature to solidify main grid electrode 160 and connection electrode 170, the selection of the temperature of curing is mainly to consider following factor: (a) prevent under condition of cure, to make the further sintering such as secondary gate electrode, backplate of sintering and quilt is burnt out; (b) the patient hot conditions of resinous material.Preferably, the scope of " low temperature " is 100-650 ℃, and it is lower than the problem temperature of high temperature sintering relatively.
So far, the electrode of solar cell shown in Figure 20 basically forms.
What need explanation is, the order of step S710 to S730 can be exchanged among Figure 21, promptly can advanced row step S720 printed back electrode or S730 print secondary gate electrode, and then carry out step S710 printing third electrode.
Contact solar cell or this a plurality of MWT shown in Figure 20 back of the body contact solar cells with the MWT back of the body shown in Figure 3 with a plurality of Fig. 2; Can assemble the formation solar module; In conjunction with shown in Figure 2; A plurality of MWT back of the body contact solar cells are connected to form the battery pack string through interconnector, add prebasal plate (being generally glass), backboard then and the layer that is sealing adhesive can form the solar module with certain power output through the lamination and the step that frames up.
Need to prove, more than among all embodiment, all being based on cell substrate is that p type conduction type describes.But those skilled in the art know knowledge, and cell substrate also can be chosen as n type conduction type, and same similar solar battery structure also can prepare formation.When cell substrate is n type conduction type; Cell substrate comprises the n semiconductor regions that is arranged on its back side and is arranged on its positive p semiconductor regions; Wherein secondary gate electrode directly is connected with the p semiconductor regions; The main grid electrode is arranged at cell backside, and backplate correspondingly is to electrically connect with the n semiconductor regions.
Above example has mainly been explained the contact of the MWT back of the body solar cell, various preparation method and solar module thereof of the present invention.Although only some of them execution mode of the present invention is described, those of ordinary skills should understand, and the present invention can be in not departing from its purport and scope implements with many other forms.Therefore, example of being showed and execution mode are regarded as schematic and nonrestrictive, are not breaking away under the situation of liking defined spirit of the present invention of each claim and scope enclosed, and the present invention possibly contained various modifications and replacement.
Claims (32)
1. a metal is around wearing type back of the body contact solar cell, and it comprises:
Cell substrate; Comprise first conductivity type regions and second conductivity type regions; Said second conductivity type regions and first conductivity type regions lay respectively at the front and back of said cell substrate, and said second conductivity type regions and first conductivity type regions form PN junction;
The secondary gate electrode that composition is formed on said second conductivity type regions and electrically connects with said second conductivity type regions;
Pass the through hole of said cell substrate, the conduction type of the inner surface of said through hole is first conduction type;
Be connected with said secondary gate electrode based on said through hole, composition is formed at the main grid electrode on said first conductivity type regions; And
Second electrode that composition is formed on said first conductivity type regions and electrically connects with said first conductivity type regions;
Wherein, said main grid electrode is non-ohmic contact with contacting of said cell substrate, also is provided with insulating barrier between perhaps said main grid electrode and the said cell substrate.
2. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said main grid electrode comprises back portion and around wearing part; Said back portion is arranged on said first conductivity type regions, saidly is arranged in the said through hole and extends on second conductivity type regions with secondary gate electrode and electrically connect around wearing part.
3. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell, and said main grid electrode is to be that 0 slurry printing and sintering form basically through frit content.
4. metal as claimed in claim 3 is characterized in that around wearing type back of the body contact solar cell said main grid electrode is silver-colored material.
5. contact solar cell like claim 1 or 3 described metals around wearing the type back of the body, it is characterized in that said solar cell also comprises the connection electrode that is used to connect said main grid electrode and said secondary gate electrode that is formed on said cell substrate front.
6. metal as claimed in claim 5 is characterized in that around wearing type back of the body contact solar cell said main grid electrode and said connection electrode all form through low-temperature setting.
7. contact solar cell like claim 1 or 2 or 3 described metals around wearing the type back of the body, it is characterized in that said main grid electrode is arranged to continuous or discontinuous.
8. contact solar cell like claim 1 or 2 or 3 described metals around wearing the type back of the body, it is characterized in that, be provided with the hollow out zone in the said main grid electrode.
9. contact solar cell like claim 1 or 2 or 3 described metals around wearing the type back of the body, it is characterized in that, also comprise the antireflection layer that is formed on said second conductivity type regions.
10. contact solar cell like claim 1 or 2 or 3 described metals around wearing the type back of the body, it is characterized in that said first conductivity type regions is the p semiconductor regions, said second conductivity type regions is the n semiconductor regions.
11. metal as claimed in claim 10 is characterized in that around wearing type back of the body contact solar cell said second electrode is an aluminium material, said second electrode and said first conductivity type regions form ohmic contact.
12. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell said solar cell comprises that also composition is formed at the third electrode on said first conductivity type regions, said third electrode and said second electrode electrically connect.
13. metal as claimed in claim 12 is characterized in that around wearing type back of the body contact solar cell said third electrode and said main grid electrode print formation synchronously.
14. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said insulating barrier is through forming in composition printing on the said through-hole inner surface and on the back side of said first conductivity type regions, and the marginal portion of said insulating barrier extends beyond the contact area of main grid electrode and cell substrate.
15. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell said main grid electrode forms through printing of silver slurry and sintering, said insulating barrier is that said silver slurry forms in said sintering process with said cell substrate.
16. metal as claimed in claim 15 is characterized in that around wearing type back of the body contact solar cell said silver slurry is for containing the silver slurry of frit, said insulating barrier is the glass medium layer that forms in the sintering process.
17. one kind like each described metal of claim 1 to 16 around the preparation method who wears type back of the body contact solar cell, it is characterized in that it comprises step:
(1) cell substrate with first conductivity type regions is provided;
(2) said cell substrate is carried out making herbs into wool and cleaning;
(3) doping of second conduction type being carried out in the front of said cell substrate is to form second conductivity type regions;
(4) etching is to remove the doped region of second conduction type except that said front;
(5) the deposition antireflection layer in the front of said cell substrate; And
(6) composition forms the main grid electrode and second electrode on said first conductivity type regions, and composition forms secondary gate electrode in the front of said cell substrate;
Wherein, also be included in location formation through hole and the step of removing the formed damage of drilling in the said cell substrate between any two steps in step (1) to (6).
18. preparation method as claimed in claim 17 is characterized in that, the step of location formation through hole is positioned between step (1) and (2) in said cell substrate, and the step of removing the formed damage of drilling realizes through the making herbs into wool in the step (2).
19. preparation method as claimed in claim 17 is characterized in that, the step of location formation through hole and the formed damage of removal drilling is positioned between step (5) and (6) in said cell substrate.
20. preparation method as claimed in claim 17 is characterized in that, in said step (6), also comprises: on said first conductivity type regions, form third electrode, said third electrode is used to realize the electric connection of said second electrode and interconnector.
21. preparation method as claimed in claim 20 is characterized in that, in said step (6), also comprises: on said second conductivity type regions, form connection electrode, said connection electrode is used to connect said main grid electrode and said secondary gate electrode.
22. preparation method as claimed in claim 21 is characterized in that, said step (6) may further comprise the steps:
(6a) composition printing third electrode on the back side of said cell substrate;
(6b) composition prints said second electrode;
(6c) composition prints said secondary gate electrode;
(6d) sintering;
(6e) with low temperature curing type condensate slurry composition printing main grid electrode and connection electrode; And
(6f) solidify.
23. preparation method as claimed in claim 22 is characterized in that, the peak temperature of said sintering is 800 ℃ basically, and the temperature range of said curing is 100 ℃-650 ℃.
24. preparation method as claimed in claim 20; It is characterized in that; In said step (6); Form said second electrode, third electrode, secondary gate electrode through printing and sintering, and be that 0 slurry printing and sintering form said main grid electrode basically, be sintered between said main grid electrode and the said cell substrate and form non-ohmic contact through frit content.
25., it is characterized in that printing earlier forms said main grid electrode like claim 17 or 24 described preparation methods, republish and form said secondary gate electrode.
26. preparation method as claimed in claim 20 is characterized in that, said third electrode and said main grid electrode are all silver-colored material, and said third electrode and said main grid electrode print formation synchronously.
27. preparation method as claimed in claim 17; It is characterized in that; In said step (6); Form said main grid electrode through printing of silver slurry and sintering, and in said sintering process, at the insulating barrier that is formed for realizing electrical isolation between said main grid electrode and the said cell substrate between said main grid electrode and the said cell substrate.
28. preparation method as claimed in claim 27 is characterized in that, said silver slurry is for containing the silver slurry of frit, and said insulating barrier is the glass medium layer.
29. preparation method as claimed in claim 17 is characterized in that, in step (6), is formed for realizing the insulating barrier of the electrical isolation between said main grid electrode and the said cell substrate in printing on the said cell substrate.
30. preparation method as claimed in claim 17 is characterized in that, in said step (4), said etching is a wet etching.
31. preparation method as claimed in claim 17 is characterized in that, forms said through hole through chemical wet etching, mechanical punching, laser drilling or electronic beam drilling.
32. solar module; It is characterized in that; Said solar module comprises a plurality of like each described solar cell of claim 1 to 16, connects through interconnector between the said solar cell, and carries out lamination and frame up back formation with prebasal plate, backboard and the layer that is sealing adhesive.
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| CN102800741A (en) * | 2011-05-27 | 2012-11-28 | 苏州阿特斯阳光电力科技有限公司 | Method for manufacturing back contact crystalline silicon solar battery piece |
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| CN103746040A (en) * | 2014-01-14 | 2014-04-23 | 南京日托光伏科技有限公司 | Low-cost back-contact cell production method suitable for mass production |
| CN108183147A (en) * | 2017-12-15 | 2018-06-19 | 南京日托光伏科技股份有限公司 | A kind of preparation method of MWT silicon solar cells |
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| CN103258916A (en) * | 2013-05-31 | 2013-08-21 | 英利集团有限公司 | MWT solar battery and manufacture method thereof |
| CN103258916B (en) * | 2013-05-31 | 2015-08-26 | 英利集团有限公司 | MWT solar cell and preparation method thereof |
| CN103746040A (en) * | 2014-01-14 | 2014-04-23 | 南京日托光伏科技有限公司 | Low-cost back-contact cell production method suitable for mass production |
| CN108352416A (en) * | 2015-08-26 | 2018-07-31 | 奈特考尔技术公司 | The system and method for emitter solar cell behind formation foil contact |
| CN108183147A (en) * | 2017-12-15 | 2018-06-19 | 南京日托光伏科技股份有限公司 | A kind of preparation method of MWT silicon solar cells |
| CN108198868A (en) * | 2017-12-22 | 2018-06-22 | 南京日托光伏科技股份有限公司 | A kind of MWT conductions core plate EVA hole opening technologies |
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| CN108878579B (en) * | 2018-05-29 | 2020-07-31 | 江苏日托光伏科技股份有限公司 | Preparation method of MWT solar cell cathode with low cost |
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