CN102760778A

CN102760778A - Solar battery, solar battery module and manufacturing method of solar battery and solar battery module

Info

Publication number: CN102760778A
Application number: CN2011101100041A
Authority: CN
Inventors: 周杰; 温建军; 蔡昭; 周豪浩; 王玉林; 臧智毅; 艾凡凡; 刘皎彦; 杨健; 陈如龙; 严婷婷; 唐应堂; 张光春
Original assignee: Wuxi Suntech Power Co Ltd
Current assignee: Wuxi Suntech Power Co Ltd
Priority date: 2011-04-29
Filing date: 2011-04-29
Publication date: 2012-10-31

Abstract

The invention provides a solar battery, a solar battery module and a manufacturing method of the solar battery and a solar battery module, belonging to the technical field of photovoltaics. The back surface of the solar battery is provided with multiple rows/lines of main grid electrodes, a back electric field, multiple rows/line of back electrodes electrically connected with the back electric field, and a first insulating medium layer, wherein the multiple rows/lines of main grid electrodes are mutually and basically parallel to the multiple rows/lines of back electrodes; and each row/line of main grid electrodes and the corresponding one row/line of back electrodes are symmetrically distributed along a central line of a battery substrate parallel to the row/line main grid electrodes. The solar battery module comprises a solar battery array string which comprises a plurality of solar batteries arranged in row/line. The solar battery has good insulating and isolating property; and when the solar batteries are assembled into the solar battery module, interconnectors are conveniently connected and the cost is low; and the solar battery module has the advantages of high reliability, low preparation cost and high production efficiency.

Description

Solar cell, solar module and preparation method thereof

Technical field

The invention belongs to the photovoltaic technology field; Relate to realize electrical isolation between main grid electrode and the back of the body electric field through non-ohmic contact or second insulating medium layer metal around wearing type (Metal Wrap Through; MWT) back of the body contact solar cell, the back side that relates in particular to solar cell are provided with the preparation method of the MWT back of the body contact solar cell of first insulating medium layer, this solar cell, the solar module that can a plurality of MWT back of the body contact solar cells be connected through interconnector and the preparation method of this solar module on same basically plane.

Background technology

Utilize application 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 solar module that forms by a plurality of solar cells series connection (being connected in series) with the interconnector welding.

Normally, solar cell comprises the pn knot that is formed on the cell substrate (like monocrystalline silicon or polysilicon), and collects the photogenerated current that produces because of shining upon on the cell substrate and it is compiled the electrode of drawing.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 back of the body electric field and back electrode with projected current.When this solar cell forms solar module through the interconnector series connection; Article one, an end of interconnector need be welded to connect back electrode at the back side of a solar cell, its other end need be welded to connect the main grid electrode in the front of another solar cell; Interconnector is not at grade, and this is unfavorable for the automated production of solar module; And,, have the bigger latent risk of splitting at the pad place of the edge of solar cell along with the continuous attenuate of cell substrate.

Along with the development of solar cell technology, proposed the main grid electrode of battery front side is placed the back of the body contact-type solar cell at the cell substrate back side in recent years.U.S. Patent number is US6,384, a kind of MWT back of the body contact solar cell is specifically disclosed in patent 317B1, that be entitled as " Solar Cell and Process of Manufacturing the Same (solar cell and preparation method thereof) ".The conventional relatively solar cell of MWT back of the body contact solar cell has conversion efficiency height, characteristics attractive in appearance; And avoided needing the situation of solder interconnections bar simultaneously, improved the conversion efficiency of solar module and be easy to solar cell is packaged into solar module at front and back.

The structural change sketch map that MWT back of the body contact solar cell is encapsulated as solar module for prior art shown in Figure 1; Wherein, Fig. 1 (a) is the structure sketch map that the MWT back of the body contacts solar cell, puts the electric connection sketch map after backboard (Back Sheet) interconnects when adopting conductive adhesive technology in the manufacturing process of Fig. 1 (b) for MWT back of the body contact solar module.In the prior art, when MWT back of the body contact solar cell is interconnected as solar module, generally adopt backboard to realize conductive adhesive technology.Shown in Fig. 1 (a), 900 substrates for MWT back of the body contact solar cell, 910 are the back electrode in the back of the body electric field (for example forming through the silver slurry), 920 for being formed at the main grid electrode at the back side.Shown in Fig. 1 (b), adopt integrated backboard 930 to be packaged into solar module at the back side of MWT back of the body contact solar cell.In the backboard 930, the one deck that contacts the solar cell contact with the MWT back of the body is weather-proof insulated substrate panel material and encapsulant; The intermediate layer is a metal film layer, through to the metal film layer composition, can realize be connected (like the white curve among the figure) of corresponding main grid electrode and back electrode; The outermost layer of backboard 930 also covers one deck insulating medium layer, and this insulating medium layer is the electrode contact hole 931 shown in the coverage diagram not.At the zone that the back electrode of solar cell or main grid electrode need electrically conduct with the metallic copper thin layer, filled conductive glue in the electrode contact hole 931 on its respective regions (for example sliver-powder conducting glue).Therefore, need electrode contact hole 931 to aim at respective electrode.Illustrated interconnection between two solar cells among Fig. 1, for a plurality of solar cells, same being suitable for.Therefore, interconnection mode shown in Figure 1 is not to adopt traditional welding manner solder interconnections bar.

But when forming solar module with interconnection mode shown in Figure 1, have following shortcoming: be connected through conducting resinl between (1) electrode and the metal film layer, reliability is lower; (2) electrode of MWT cell backside need accurately be aimed at corresponding electrode contact hole on the metallic film, needs accurately control in the technical process, and complicate fabrication process, difficulty are higher; (3) accomplish above interconnection process devices needed costliness, increase the cost of solar module virtually; (4) backboard, encapsulant and the sliver-powder conducting glue price of the weather-proof insulation of surface coverage metallic film (for example copper film material) are higher, have increased the cost of solar module.

Summary of the invention

One of the object of the invention is, the MWT back of the body contact solar cell that a kind of isolation characteristic that insulate is good, be convenient to be assembled into through interconnector solar module is provided.

Two of the object of the invention is, provides a kind of conventional welding manner or conductive tape bonding way can used to realize that interconnector interconnection MWT back of the body contact solar cell forms solar module.

Above-mentioned purpose of the present invention or other purpose realize through following technical scheme:

According to one side of the present invention, a kind of MWT back of the body contact solar cell is provided, it comprises:

Cell substrate comprises first conductivity type regions that is positioned at its back side and second conductivity type regions that is positioned at its front, and said second conductivity type regions and said first conductivity type regions form PN junction;

A plurality of through holes, it passes said cell substrate, and the conduction type of said through-hole inner surface is first conduction type;

Secondary gate electrode, it is positive that it is arranged at said cell substrate;

Multirow/row main grid electrode, it is arranged at the said cell substrate back side and electrically connects through through hole in the said cell substrate and said secondary gate electrode;

Back of the body electric field, it is arranged at the said cell substrate back side;

Multirow/row back electrode, it is used to export the collected electric current of said back of the body electric field and the interconnection between the said solar cell when being used to be packaged into assembly; And

First insulating medium layer, it is arranged at the back side of said cell substrate;

Wherein, said main grid electrode is non-ohmic contact with contacting of said cell substrate, also is provided with second insulating medium layer between perhaps said main grid electrode and the said cell substrate;

Mutual substantially parallel setting between multirow/row main grid electrode and multirow/row back electrode, every row/row main grid electrode is along the center line and the corresponding delegation/row back electrode symmetry arrangement of cell substrate in parallel;

Operationally connect through interconnector between two said solar cells, said first insulating medium layer is used to prevent that said interconnector is electrically connected at the said main grid electrode and the said back of the body electric field of same said solar cell simultaneously.

In one embodiment, when said main grid electrode was non-ohmic contact with contacting of said cell substrate, said main grid electrode was 0 slurry printing and sintering formation basically through frit content.

In another embodiment; When being provided with second insulating medium layer between said main grid electrode and the said cell substrate; Said main grid electrode forms through printing of silver slurry and sintering, and said second insulating medium layer is that said silver slurry forms in said sintering process with said cell substrate.

In the above MWT that reaches back of the body contact solar cell, preferably, said silver slurry is the silver slurry that contains frit, and said second insulating medium layer is the glass medium layer that forms in the sintering process.

In going back an embodiment; Said second insulating medium layer 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 second insulating medium layer extends beyond the contact area of main grid electrode and cell substrate.

According to MWT back of the body contact solar cell provided by the invention, preferably, the said main grid electrode of every row/row is by the segmentation setting.

Preferably, said through hole is provided with on said secondary gate electrode equal intervals ground, and m the through hole that lays respectively on the said secondary gate electrode of m bar basically point-blank arranged by row/row, and wherein, m is the integer more than or equal to 3.

Preferably, said solar cell also comprises the through hole connecting line that is arranged at said cell substrate front, and said through hole connecting line connects the said through hole of arranging by row/row.

Preferably, on the said through hole connecting line, also be provided with one or more through holes between the adjacent said secondary gate electrode.

Preferably, the live width scope of said through hole connecting line can be 100 microns to 1 millimeter basically.

In a further example, the bar number of said secondary gate electrode is n, and n is greater than m, by said m through hole discontinuous arrangement on the secondary gate electrode of n bar of row/row arrangement.

Preferably, in the said main grid electrode hollow out zone is set.

Preferably, said back of the body electric field is aluminium or aluminum alloy materials, and said back of the body electric field and said first conductivity type regions form ohmic contact.

Preferably, said solar cell also comprises the antireflection layer that is formed at said cell substrate front.

Preferably, silk screen printing simultaneously of said main grid electrode and back electrode or steel mesh printing form.

According to MWT back of the body contact solar cell provided by the invention; Wherein, Said first insulating medium layer is banded, and said first insulating medium layer is on the cell substrate between said row/row main grid electrode and the said back of the body electric field and partly cover the edge and the said back of the body electric field of part of said main grid electrode.

Preferably, the width of said first insulating medium layer is greater than the width of said interconnector.

Also embodiment according to MWT back of the body contact solar cell provided by the invention; Wherein, Equidistantly distribute with first spacing between said multirow/row main grid electrode, equidistantly distribute with second spacing between said multirow/row back electrode, said first spacing equals said second spacing.

Preferably, said first insulating medium layer is processed by low temperature curing type organic substance material or high temperature sintering type inorganic non-metallic oxide material.

According to another aspect of the present invention, the method for the above MWT back of the body contact solar cell of preparation is provided, it may further comprise the steps:

Cell substrate with first conductivity type regions is provided;

The location forms through hole in said cell substrate;

The doping of said cell substrate surface being carried out second conduction type is to form the second conduction type doped region;

The second conduction type doped region of etching except that the front of said cell substrate is to form the second positive conductivity type regions of said cell substrate;

Composition forms main grid electrode and back electrode on the said cell substrate back side;

Composition forms back of the body electric field on the said cell substrate back side;

Composition forms secondary gate electrode in said cell substrate front; And

Form first insulating medium layer in said cell substrate back-patterned.

Preferably, after forming through hole, also comprise step: said cell substrate is carried out making herbs into wool and cleaning, and remove system formed damage of through hole and residue.

Preferably, carry out also comprising step after the doping of second conduction type: remove phosphorosilicate glass.

Preferably, carry out also comprising step after the doping of second conduction type: deposition antireflection layer in the front of said cell substrate.

Preferably, when composition formed secondary gate electrode, also composition formed the through hole connecting line in said cell substrate front simultaneously.

Preferably, the composition of said main grid electrode, back electrode, back of the body electric field, secondary gate electrode realizes that through silk screen printing or steel mesh printing said main grid electrode, back electrode form through identical slurry.

In one embodiment, said main grid electrode to form through frit content be that 0 slurry printing and sintering form basically, said main grid electrode is non-ohmic contact with contacting of said cell substrate.

In another embodiment, forming through printing of silver slurry and sintering of said main grid electrode forms, and in said sintering process, is formed on second insulating medium layer between said main grid electrode and the said cell substrate simultaneously.

Preferably, said silver slurry is for containing the silver slurry of frit, and said second insulating medium layer is the glass medium layer that forms in the sintering process.

In an embodiment also, this preparation method also comprises step: the composition printing forms said second insulating medium layer on the back side of the inner surface of said through hole and said first conductivity type regions; Wherein, the marginal portion of said second insulating medium layer extends beyond the contact area of main grid electrode and cell substrate.

According to preparation method provided by the invention, wherein, said etching is a wet etching, and said cell substrate floats in the employed etching liquid of wet etching with facing up.

According to one side more of the present invention; A kind of solar module is provided; Comprise the solar panel string; Said solar panel string comprises that a plurality of aforesaid any one metals of arranging by row/row are around wearing type back of the body contact solar cell; Connect through interconnector between adjacent two said solar cells in the solar cell of every row/row, every interconnector is connected to the back electrode of corresponding line/row of main grid electrode and another said solar cell of the corresponding line/row of a said solar cell simultaneously on same basically plane, same basically straight line.

Preferably, in two the adjacent said solar cells in same delegation/said solar cell of row, one of them said solar cell another said solar cell Rotate 180 degree relatively is provided with.

Preferably, said interconnector be connected to be welded to connect or conductive tape bonding.

Preferably, said solar module also comprises front light-transmitting substrate, positive face seal adhesive linkage, sealing backside adhesive linkage, back substrate, and said positive face seal adhesive linkage and sealing backside adhesive linkage coat said solar panel string.

Also on the one hand a kind of method for preparing the above solar module that reaches is provided according to of the present invention, it may further comprise the steps:

The above any a plurality of metal that reach is arranged by row/row around wearing type back of the body contact solar cell;

Arrange every row/be listed as said solar cell, so that the back electrode of the corresponding line/row of the main grid electrode of the corresponding line/row of a said solar cell in adjacent two said solar cells and another said solar cell is on same basically straight line; And

On same basically plane, connect interconnector.

Preferably, in adjacent two said solar cells, one of them said solar cell is another said solar cell Rotate 180 degree relatively.

Preferably, through being welded to connect or the bonding mode of conductive tape realizes the connection of interconnector.

Technique effect of the present invention is, through with mutual substantially parallel setting between multirow/row main grid electrode and the multirow/row back electrode, every row/row main grid electrode is along the center line and the corresponding delegation/row back electrode symmetry arrangement of cell substrate in parallel; Assemble solar module thereby can connect interconnector easily, the cost that interconnector connects is low; Every interconnector connects two solar cells basically on same plane, same straight line, is difficult for producing latent splitting in the edge of solar cell, and reliability is high, cost is low, production efficiency is high, and can guarantee the high conversion efficiency of solar cell.In addition, because the existence of first insulating medium layer of back of solar cell, the insulation isolation characteristic of solar cell is good.

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, wherein, same or analogous key element adopts identical label to represent.

Fig. 1 is the structural change sketch map that MWT back of the body contact solar cell is encapsulated as solar module of prior art; Wherein, Fig. 1 (a) is the structure sketch map that the MWT back of the body contacts solar cell, puts the electric connection sketch map after backboard (Back Sheet) interconnects when adopting conductive adhesive technology in the manufacturing process of Fig. 1 (b) for MWT back of the body contact solar module.

Fig. 2 is that wherein, Fig. 2 (a) is the structure sketch map of this solar cell according to the partial schematic diagram of the structure of the MWT back of the body contact solar cell of one embodiment of the invention, and Fig. 2 (b) is the Facad structure sketch map of this solar cell.

Fig. 3 is the structure for amplifying sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts A part in the solar cell.

Fig. 4 is the structure for amplifying sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts B part in the solar cell.

Fig. 5 is the C-C cross section structure sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts solar cell.

Fig. 6 is the structure for amplifying sketch map of A part among Fig. 5, and wherein Fig. 6 (a) is an instance wherein, and Fig. 6 (b) is another instance wherein.

Fig. 7 contacts the process sketch map of solar cells interconnection with the solar panel string of formation solar module with a plurality of MWT back ofs the body shown in Figure 2; Wherein, Fig. 6 (a) is the arrangement mode sketch map of polylith solar cell 500, and Fig. 6 (b) is welded to connect the structural representation of the solar panel string of back formation through interconnector for polylith solar cell 500.

Fig. 8 is the decomposition texture sketch map of the solar module that provides according to one embodiment of the invention.

Fig. 9 is the method flow sketch map of preparation solar cell embodiment illustrated in fig. 2.

Figure 10 is extremely shown in Figure 180 to be to change sketch map according to preparation method's structure of process shown in Figure 9.

Figure 19 is the second embodiment method flow sketch map of preparation solar cell embodiment illustrated in fig. 2.

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.

" 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 one embodiment of the invention, and wherein, Fig. 2 (a) is the structure sketch map of this solar cell, and Fig. 2 (b) is the Facad structure sketch map of this solar cell.Shown in Figure 3 is the structure for amplifying sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts A part in the solar cell.Shown in Figure 4 is the structure for amplifying sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts B part in the solar cell.Shown in Figure 5 is the C-C cross section structure sketch map that the MWT back of the body embodiment illustrated in fig. 2 contacts solar cell.Shown in Figure 6 is the structure for amplifying sketch map of A part among Fig. 5., the MWT back of the body contact solar cell of this embodiment is elaborated to shown in Figure 6 in conjunction with Fig. 2.

The MWT back of the body contact solar cell 500 of this embodiment forms based on cell substrate 510.In this embodiment, select p type monocrystalline silicon piece or polysilicon chip 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 510 can also be the solar cell basis material of polycrystalline silicon material or other type.The cell substrate 510 of solar cell can be chosen as the shape of symmetry structure; For example; Can be approximate rectangle or square; Its concrete shape does not receive illustrated embodiment restriction (for example also possibly can be parallelogram) yet, confirms the factor of the shape (yet being the shape of solar cell 500) of cell substrate 510, with describing in the solar module thereafter.As shown in Figure 5, in this embodiment, comprise p semiconductor regions 512 that substrate itself provides and the n semiconductor regions 511 that the front that is entrained in cell substrate of cell substrate 510 is formed in the cell substrate 510.The thickness range of n semiconductor regions 511 can be 0.1 micron to 1 micron.P semiconductor regions 512 and the n semiconductor regions 511 common pn knots that form solar cell; The secondary gate electrode 530 of the electric current of n semiconductor regions through the front (also being the front of cell substrate 510) of solar cell collect and further the main grid electrode 550 through the back side compile and draw, the back of the body electric field 560 of the electric current of p semiconductor regions 512 through solar cell compiles and drawn by back electrode 561.

Consult Fig. 2 (b) and Fig. 4, form some secondary gate electrodes 530 on the front 520 of solar cell, routinely; Secondary gate electrode 530 is with the wire setting; The live width of secondary gate electrode 530 is about 30 microns to 140 microns, and rule is evenly distributed between many secondary gate electrodes, helps collecting the electric current of n semiconductor regions 511 like this; For example, parallel and equidistantly laterally arrange between the secondary gate electrode.But the live width of the spacing between the secondary gate electrode 530 and secondary gate electrode 530 itself etc. is not limited by the present invention.Normally; Secondary gate electrode 530 is to form with silk screen (or steel mesh) printing conductive silver slurry sintering; In this embodiment, secondary gate electrode 530 is formed in positive n semiconductor regions 511 surfaces and goes up and electrically connect with the n semiconductor regions, thereby can collect its photogenerated current.

For forming MWT back of the body contact solar cell, on the cell substrate of secondary gate electrode 530 corresponding positions, can form the through hole 590 that several penetrate cell substrate 510 (also promptly passing n semiconductor regions 511 and p semiconductor regions 512).On every or some secondary gate electrode 530, separated by a distance after can and 550 interconnections of main grid electrode, thereby main grid electrode 550 can compile and draw the electric current that secondary gate electrode 530 is collected effectively.In this embodiment; Can select wherein to form a plurality of through holes 590 on some secondary gate electrodes 530; Preferably, on many secondary gate electrodes 530 that are arranged in parallel, the layout that is in line in the horizontal of the through hole on the secondary gate electrode 530 of each bar; Many the through hole connecting lines 555 that are basically perpendicular to secondary gate electrode are set on n semiconductor regions 511 surfaces; Through hole connecting line 555 conducting that can (promptly with delegation) through hole point-blank be linked together, therefore, some secondary gate electrode 530 that through hole 590 is not set also can be collected to the main grid electrode 550 at the back side through through hole connecting line 555; So, reduced the position accuracy demand (when through hole is not arranged on the place, crosspoint of through hole connecting line 555 and secondary gate electrode 530, also can realize the electric connection of secondary gate electrode and back side main grid electrode) of system through hole.Schematically; Be formed with through hole 590 as being provided with altogether among Fig. 2 (b) on 530,28 secondary gate electrodes of 57 secondary gate electrodes, wherein; On 4 secondary gate electrodes arranging continuously through hole is set; On 4 secondary gate electrodes arranging continuously in addition through hole is not set, 4 secondary gate electrode and 4 secondary gate electrodes that through hole is not set that through hole is set are spaced, and promptly realize through hole non-arrangement fully continuously on all secondary gate electrodes; Be provided with on the secondary gate electrode of through hole, 3 through hole spaced sets, 3 through hole connecting lines 555 be arranged in parallel equally spacedly and with secondary gate electrode 530 square crossings, through hole is arranged on the place, crosspoint of secondary gate electrode 530 and through hole connecting line 555; Correspondingly, shown in Fig. 2 (a), the 550 segmentation settings of main grid electrode; One section main grid electrode that the corresponding back side of 4 continuous through holes on the through hole connecting line 555 is provided with, therefore, corresponding to arranging fully continuously with the non-of the through hole in the delegation; Main grid electrode 550 is divided into 7 sections; By rows, 7 sections of delegation, triplex row altogether.Therefore, through above concrete setting, positive n semiconductor regions 511 electric currents compile with the mode of low relatively series resistance draws.Because through hole connecting line 555 laterally arranges equally spacedly, therefore, triplex row main grid electrode 550 also is to laterally arrange basically equally spacedly.

Need to prove that the segments of the concrete quantity of secondary gate electrode, the concrete quantity of through hole connecting line, main grid electrode etc. is not restrictive, those skilled in the art can be provided with each respective numbers according to the enlightenment of above illustrative example.

Particularly, through hole 590 can form through methods such as chemical corrosion, mechanical punching, laser drilling, electronic beam drillings.Through hole connecting line 555 can form through modes such as silk screen printings with secondary gate electrode 530, and the width of through hole connecting line 555 is little a lot of with respect to traditional width that is arranged at positive main grid electrode, and for example, its width range is between 100 microns to 1 millimeter.

In other instance; Also can every secondary gate electrode equal intervals some through holes are set; Through hole on the different secondary gate electrodes is laterally being arranged by row with straight line continuously; Thereby on the same main grid electrode at the equal drainage of all secondary gate electrodes to the back side (main grid not segmentation of electrode this moment and front no longer are provided with through hole connecting line 555), every main grid electrode also laterally arranges basically equally spacedly.Those skilled in the art are to be understood that; Through hole arrangement mode is set; Also have many alternate manners, for example, two shared through holes of secondary gate electrode or the like; Decide the position of main grid electrode through arranging lead to the hole site, make the main grid electrode of arranging by row (or by row) equidistantly (be meant between the row or the spacing between the row) the parallel setting.Need to prove, in the above instance, for delegation's (or row) main grid electrode during by segmentation, section with section between spacing might not require to equate that it is not restrictive.

In a preferred embodiment, as shown in Figure 4, between two secondary gate electrodes 530 that through hole 590 is set and on through hole connecting line 555; Can increase again 1 through hole (shown in dotted line circle among the figure) is set; Like this, 8 through holes of arranging continuously can be connected to same section main grid electrode simultaneously, can more reliably the electric current on the through hole connecting line 555 be led to the main grid electrode at the back side; Improve the ducting capacity of electric current, reduce the series resistance of battery.In other instance, between two secondary gate electrodes 530 that through hole 590 is set and on through hole connecting line 555, increase the through hole that is provided with and also can also be two or more.

Continue to consult 3 and Fig. 5; In this embodiment, triplex row main grid electrode 550 in parallel to each other by rows, it can be laterally arranged basically equally spacedly; Main grid electrode 550 comprises back portion 550a and around wearing part 550b, the two all is to form through integrated printing.Back portion 550a is arranged on the p semiconductor regions 512; Be arranged in the said through hole and extend on the n semiconductor regions 511 around wearing part 550b; Thereby realize be connected (structure roughly as shown in Figure 5) with secondary gate electrode 530, can avoid the electrode material of secondary gate electrode 530 to get in the through hole 590 like this and with the p semiconductor regions 512 formation ohmic contact of through hole 590.Every main grid electrode 550 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 550 is discontinuous (as shown in Figure 2), also promptly is made up of the block main grid electrode of multistage.In addition, (being on the p semiconductor regions 512) also forms back of the body electric field 560 on the back side of cell substrate.According to the basic principle of solar cell, between the back of the body electric field 560 and the main grid electrode 550 (being directly electrically connection between positive pole and the negative pole of pn knot) that needs electrical isolation.Therefore, through through hole 590 cause cell substrate 510 the back side main grid electrode 550 need with cell substrate electrical isolation (especially need with p semiconductor regions 512 electrical isolation).

Shown in Figure 6 is the structure for amplifying sketch map of A part among Fig. 5, and wherein Fig. 6 (a) is an instance wherein, and Fig. 6 (b) is another instance wherein.Main grid electrode 550 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 510 to be realized:

First kind; Shown in Fig. 6 (a); To form in the instance of main grid electrode 550 through silver slurry silk screen printing and sintering, main grid electrode 550 is non-ohmic contact at the inner surface place of through hole 590 with contacting of cell substrate 510 (for example the p semiconductor regions 512), and is same; Main grid electrode 550 also is non-ohmic contact with the contacting of (for example the p semiconductor regions 512) at the back side of cell substrate 510; Like this, the electric current that p semiconductor regions 512 is produced can not flow to main grid electrode 550, thereby can not form the loop with the electric current that n semiconductor regions 511 is produced; Preferably, to be chosen as glass (glass) material content be 0 silver paste basically for silver slurry.

Second kind; Shown in Fig. 6 (b); Realize electrical isolation through second insulating medium layer 551 is set between main grid electrode 550 and cell substrate 510, in this example, main grid electrode 550 forms with slurry silk screen printing and sintering; Second insulating medium layer 551 can be formed on the backside surface of inner surface and p semiconductor regions 512 of through hole 590 through printing; Thereby when forming main grid electrode 550 with silver slurry silk screen printing and sintering, the silver slurry does not directly contact with cell substrate 510, and second insulating medium layer 551 can be nonconducting nonmetal oxide material; In addition; In sintering process; Second insulating medium layer 551 also can be through spontaneously forming at the contact area of silver slurry with cell substrate 510 (for example the p semiconductor regions 512), and preferably, the silver slurry is chosen as the slurry that contains glass (glass) material; The mass percent scope of frit in silver slurry is 1%-80% (for example 35%); Thereby can be implemented in the sintering process, the frit composition can concentrate on cell substrate 510 forms thin layer with the contact-making surface place of slurry glass medium layer, also is second insulating medium layer 551.

In above first kind of instance; For as much as possible guaranteeing to form non-ohmic contact between main grid electrode 550 and the cell substrate 510; Realize the electrical isolation between the positive and negative electrode, preferably, the scope of the resistivity of cell substrate 510 (for example p type doping content) is 0.1ohm Cm-20ohm Cm.

In other preferred embodiment, hollow out zone (not shown) can be set on the main grid electrode 550, thereby reduce the contact area of metal and silicon, effectively reduce the recombination rate of metal and silicon, and the consumption of minimizing metal paste, reduce cost.

Continue to consult Fig. 2 and Fig. 5; Back of the body electric field 560 is formed directly on the backside surface of p semiconductor regions 512 and with p semiconductor regions 512 and electrically connects, thereby can the electric current of p semiconductor regions 512 collected and draw through the back of the body electric field 560 of solar cell.Preferably; For reducing p semiconductor regions 512 and the contact resistance of carrying on the back electric field 560; As shown in Figure 3, back of the body electric field 560 selects IIIA bunch metallic element as back of the body electric field 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 512 it is further carried out the doping of p type; Thereby form the zone 580 of relative high-dopant concentration, zone 580 is easy to and carries on the back electric field 560 to form ohmic contact, and reduce contact resistance; Most of back of the body electric field material still is retained in the back side and has formed aluminium back of the body field, also promptly carries on the back electric field 560.Need to prove; The zone 580 and the p semiconductor regions 512 of high-dopant concentration normally do not have obvious boundary as shown in Figure 5; This is because with back of the body electric field during as doped source; According to the characteristics of diffusing, doping, doped chemical aluminium diffuses in the p semiconductor regions 512 with the concentration gradient mode.

In back of the body electric field 560 zones, back electrode 561 is set also, one of its function is to realize to carry on the back being connected between electric field and the interconnector, and two of its function is the electric current of back of the body electric field 560 is further led to interconnector.Back electrode 561 is surrounded by back of the body electric fields 560, so the n semiconductor regions of back electrode 561 corresponding contacts are also isolated by additional doped region 580, so it can not cause pn to tie the short circuit of both positive and negative polarity.In this embodiment, as shown in Figure 2, the cell substrate 510 of solar cell is a square, and also as main grid electrode 550, back electrode 561 is provided with by row back electrode 561, and one side correspondence of every capable main grid electrode 550 is provided with delegation's back electrode 561.For making solar cell at grade behind the Rotate 180 °, every capable main grid electrode can align with the back electrode of the corresponding line of another adjacent solar cell basically, and every capable back electrode also can align with the main grid electrode of the corresponding line of another adjacent solar cell basically; Every capable back electrode is along the center line 501 and every capable main grid electrode symmetry arrangement of cell substrate 510, and center line 501 is parallel to main grid electrode 550, and laterally arranges between all row back electrodes.The line number of back electrode 561 (or columns) equates with the line number (or columns) of main grid electrode 550; Laterally arrange equally spacedly between the multirow back electrode 561; Laterally arrange equally spacedly between the multirow main grid electrode 550; And the spacing of adjacent lines back electrode 561 equals the spacing between the adjacent lines main grid electrode 550.Normally, single back electrode 561 is generally point-like (being used for being connected with interconnector), and multiple spot back electrode 561 (for example figure shown in 11) is arranged and formed row.When 550 segmentations of main grid electrode are provided with the discontinuous setting of main grid electrode of delegation (also with), on the electric current of the back of the body electric field 560 of a side of main grid electrode 550 can the back electrode 561 through back of the body electric field drainage to its opposite side between the intersegmental crack of main grid electrode.

Continue to consult Fig. 5, in another specific embodiment, solar cell 500 also comprises and is deposited on cell substrate 510 antireflection layer 513 positive, on the n semiconductor regions 511.Antireflection layer 513 can be materials such as silicon nitride, and its concrete thickness range can be the 50-120 nanometer.Through antireflection layer 513 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 500 of above embodiment, do not form isolation channel or accurate wet etching formation isolation channel because the isolation between the positive and negative electrode need not draw to carve through laser, therefore, its conversion efficiency is higher relatively.

It is shown in Figure 7 for a plurality of MWT back ofs the body shown in Figure 2 are contacted the process sketch map of solar cells interconnection with the solar panel string of formation solar module; Wherein, Fig. 7 (a) is the arrangement mode sketch map of polylith solar cell 500, and Fig. 7 (b) is welded to connect the structural representation of the solar panel string of back formation through interconnector for polylith solar cell 500.Normally, the solar panel string is to form (i.e. the main grid electrode of a solar cell connect another piece solar cell back electrode) through the polylith solar cell both positive and negative polarity of connecting successively.Below in conjunction with Fig. 7, structure of solar panel string 5000 and preparation method thereof is described.

Consult Fig. 7 (a), being connected in series with three solar cells shown in Figure 2 500 forms solar panel string 5000 and carries out schematic illustration.Three solar cells are respectively 500A, 500B, 500C; In this example; At first with they (also can by row) by rows; Wherein, Solar cell 500B is with respect to

solar cell

500A or 500C Rotate 180 degree, thus can be with delegation's main grid electrode of one of them solar cell (for example solar cell 500A) delegation's back electrode of the solar cell (for example solar cell 500B) adjacent align basically point-blank (this be because every capable back electrode 561 along the center line 501 and every capable main grid electrode symmetry arrangement of cell substrate 510) with another.When the solar cell basic setup is square shape (when perhaps being oblong-shaped), the edge of solar cell by rows also can align.

Further; Consult Fig. 7 (b), an end of every interconnector 940 wherein delegation's main grid electrode of a solar cell (for example 500A) connects, and its other end connects alignment delegation's back electrode point-blank of another adjacent block solar cell (for example 500B); Particularly; Being connected between interconnector 940 and main grid electrode or the back electrode can be welding connecting mode, also can be other connected mode (for example adopting the bonding mode of conductive tape).Shown in Fig. 7 (b), in this embodiment, three interconnectors are welded to connect solar cell 500A and 500B, and it is connected in series the main grid electrode of solar cell 500A and the back electrode of solar cell 500B; Article three, interconnector is welded to connect solar cell 500B and 500C, and it is connected in series the main grid electrode of solar cell 500B and the back electrode of solar cell 500C; Arranged crosswise successively between colleague's solar cell, thus can realize interconnection easily.Therefore; Interconnection between the solar cell can realize connecting through conventional welding manner, and every welding bar is welded to connect two solar cells basically on same plane, same straight line; With respect to being welded to connect and the interconnection connected mode of existing MWT back of the body contact solar cell of traditional solar cell; Its (for example can adopt conventional welding manner to connect) easy to connect also is difficult for producing latent splitting in the edge of solar cell, and reliability is high, cost is low; The production in enormous quantities (production efficiency is high) of solar module can be guaranteed, and the high conversion efficiency of solar cell can be guaranteed.

When interconnector 940 connects the main grid electrode of solar cell, must avoid interconnector 940 perhaps to carry on the back electric field and electrically connect with the cell substrate of this solar cell; Equally, when interconnector 940 is welded to connect the back electrode of a solar cell, must avoid the interconnector 940 and the main grid electrode of this solar cell to electrically connect.Therefore; Like Fig. 7 and shown in Figure 2, realize above purpose through first insulating medium layer 540, particularly; First insulating medium layer, 540 banded settings; Corresponding every capable main grid electrode 550 is provided with banded first insulating medium layer 540, and the cell substrate zone (part p semiconductor regions 512) between main grid electrode 550 and the back of the body electric field 560 is by 540 coverings of banded first insulating medium layer, first insulating medium layer 540 and partly cover the edge of main grid electrode 550; Cover part back of the body electric field 560 (for example, the edge of the part of the back of the body electric field between the gap of the main grid electrode 550 of overlay segments, back of the body electric field etc.) partly also.One end of interconnector 940 places 550 last times of main grid electrode, first insulating medium layer 540 can realize that back of the body electric field 560 insulation of itself and same solar cell isolate; The other end of interconnector 940 is connected in 561 last times of back electrode, and first insulating medium layer 540 can further reduce the probability of interconnector 940 and main grid electrode 550 short circuits of same battery.Therefore, battery component isolation characteristic shown in Figure 6 is good.Preferably, the width of interconnector 940 is less than the width of banded first insulating medium layer 540.

Structural representation for the solar module that provides according to one embodiment of the invention shown in Figure 8.The solar module of this embodiment comprises the solar panel string 5000 of embodiment as shown in Figure 6, also mainly comprises front light-transmitting substrate 5100, positive face seal adhesive linkage 5200A, sealing backside adhesive linkage 5200B, back substrate 5300.Front light-transmitting substrate 5100, positive face seal adhesive linkage 5200A, solar panel string 5000, sealing backside adhesive linkage 5200B, back substrate 5300 set gradually by under last, and positive face seal adhesive linkage 5200A and sealing backside adhesive linkage 5200B coat solar panel string 5000 basically.Particularly; Front light-transmitting substrate 5100 can be high-intensity armorplate glass;

Sealing adhesive linkage

5200A and 5200B can select shock resistance and the better adhesive material of durability, for example, can select using plasma encapsulant, PVB (Polyvinyl Butyral; Polyvinyl butyral resin) material, EVA material etc., back substrate 5300 can be selected TPT (polyvinyl fluoride composite membrane) substrate or armorplate glass etc.Other detail parts of solar module detail at this no longer one by one.

The first embodiment method flow sketch map for preparation solar cell embodiment illustrated in fig. 2 shown in Figure 9.Figure 10 is extremely shown in Figure 180 to be to change sketch map according to preparation method's structure of process shown in Figure 9.Preparation method's process of this solar cell is described below in conjunction with Fig. 2, Fig. 9 to Figure 18.

At first, step S410 provides the cell substrate with first conductivity type regions.

Consult Figure 10, in this embodiment, solar cell is based on cell substrate 510 preparations and forms, and selects p type monocrystalline silicon or polysilicon as cell substrate 510 (also promptly first conduction type is the p type).Particularly, the electrical resistivity range of p type monocrystalline silicon (original silicon chip substrate) can be 0.1ohm Cm to 20ohm Cm, but this is not restrictive, and p type cell substrate 510 can directly be used to form first conductivity type regions 512.By solar light irradiation, cell substrate is chosen as the shape of symmetry structure when solar cell is worked in the front 520 of cell substrate 510, for example, can be rectangle or square.

Further, step S420, the location forms through hole in said cell substrate.

Consult Figure 11, on cell substrate 510, form several through holes 590, through hole 590 penetrates into the back side of cell substrate from the front of cell substrate.Methods such as through hole 590 can chemical corrosion, mechanical punching, laser drilling, electronic beam drilling form, and normally, select laser drilling to form.Through hole can be chosen as the substantial cylindrical hole, and its diameter range is about 10 microns to 1000 microns.Location layout and the quantity of through hole 590 in cell substrate can be with reference to Fig. 2 and Fig. 4 and above related description thereof.

Need to prove, after step 420, also generally include step 425 (not shown), promptly cell substrate is carried out making herbs into wool and cleaning, and remove system formed damage of through hole and residue.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 590 is also by formed matte roughening simultaneously, and this helps improving the reliability that slurry is filled.

Further, step 430 is mainly carried out the doping of second conduction type to the front of cell substrate.

Consult shown in Figure 12ly, in this embodiment, n type mix (also i.e. second conduction type) is carried out in the front of cell substrate 510; 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 510 inevitably; The inner surface of same through hole 590 also is doped, and therefore can form the n N-type semiconductor N doped region 511a on cell substrate shown in figure 12 510 surfaces, and this moment, n N-type semiconductor N doped region 511a coated p semiconductor regions 512 basically.Particularly, can select methods such as diffusing, doping, ion implantation doping to mix.

Further, step S440, wet etching is removed the side of cell substrate and the doped region of second conduction type on the back side.

Such as step S440 description, main when mixed in the front of cell substrate, can (for example side) be mixed simultaneously in the place outside the positive top layer inevitably.Shown in figure 13; Can cell substrate 510 be floated in the etching liquid; Wherein face up; Thereby the front of cell substrate 510 can not be etched, and other n type zones (the for example hole wall of through hole, side of substrate and/or the back side) except that the n N-type semiconductor N doped region in front will be etched away, thereby n N-type semiconductor N doped region 511a is formed the n semiconductor regions 511 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 510 floats in the etching liquid; Because the capillary effect of liquid level, in the positive edge of cell substrate 510, 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 510 by etching (not shown) partly; The corner, edge that also is n semiconductor regions 511 will be by etching partly, and still, its zone that is etched is limited.

Need to prove, in this wet etching process, can remove the phosphorosilicate glass layer that forms on cell substrate 510 surfaces in the doping process simultaneously.

Further, step S450, deposition antireflection layer in the front of said cell substrate.

Consult Figure 14; In this embodiment, the antireflection layer 513 of positive deposition on the n semiconductor regions, it can pass through methods such as PECVD, LPCVD or APCVD and form; Antireflection layer 513 can be chosen as materials such as silicon nitride, and its concrete thickness range can be the 50-120 nanometer.Through antireflection layer 513 is set, can effectively improve the conversion efficiency of solar cell.

Further, step S460 print filling vias with formation main grid electrode in said cell substrate back-patterned, and printing forms back electrode simultaneously.

Consult Figure 15; In this embodiment, can form main grid electrode 550 and back electrode 561 with the mode composition of silk screen printing or steel mesh printing, in this process; Slurry (for example silver slurry) is filling vias 590 simultaneously, thereby forms the back portion 550a of main grid electrode 550 and around wearing part 550b.In this step, can select type (for example using the filling perforation slurry of specific type) and/or the sintering process of slurry etc., so that main grid electrode 550 basically forms the non-ohmic contact or second insulating medium layer 551 with p semiconductor regions 512.The particular location layout of main grid electrode 550, back electrode 561 etc. can be with reference to Fig. 2, Fig. 3, Fig. 6 and above related description thereof.

For realizing the electrical isolation of main grid electrode 550 and cell substrate 510, in this step S460, can realize through dual mode:

First kind of mode; Shown in Fig. 6 (a); To form in the process of main grid electrode 550 through silver slurry silk screen printing and sintering; Main grid electrode 550 employed first kind of silver slurry are that frit content is 0 silver slurry basically, form non-ohmic contact between main grid electrode 550 and the cell substrate 510 (for example the p semiconductor regions 512);

The second way shown in Fig. 6 (b), will form in the process of main grid electrode 550 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 510 and slurry, thereby forms the glass medium layer of thin layer, also is second insulating medium layer 551; This second insulating medium layer 551 is formed between cell substrate 510 and the main grid electrode 550, thereby can realize the basic insulation isolation between main grid electrode 550 and the cell substrate 510.

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 550 employed first kind of silver slurry frit content are 0 basically; The formed main grid electrode 550 of silver slurry will can not form ohmic contact (yet promptly can not form silver-colored silicon alloy) with cell substrate, and make between main grid electrode 550 and its cell substrate that is directly contacted and keep electrical isolation.

Need to prove, in 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 550; 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.

In addition; Preferably; When silk screen printing forms main grid electrode 550, pattern that can also be through half tone is set, when printing forms main grid electrode 550, form some hollow outs zone (not shown), thereby can reduce the contact area of main grid electrode metal and silicon (also being P type semiconductor regional 512) greatly; Reduce the compound of metal and silicon effectively, and then improve the conversion efficiency of solar energy.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 on the main grid electrode is not restricted type, and it is not to influence the principle that is connected to of metal in main grid electrode and the through hole.

Further, step S470 forms back of the body electric field in said cell substrate back-patterned.

Consult Figure 16, in this embodiment, back of the body electric field 560 can be through the silk screen printing aluminium paste in cell substrate 510 back sides, and process sequence can be between the formation of formation that forms main grid electrode 550 and secondary gate electrode 530.When selecting aluminium (it belongs to III A bunch metallic element) as back of the body electric field material; Aluminium can further carry out the p type to the p semiconductor regions 512 that it contacted and mix (particularly in the metallization processes that forms the aluminium electrode; Sintering process for example); Thereby form the zone 580 of relative high-dopant concentration, make zone 580 be easy to form ohmic contact, and reduce contact resistance with backplate 560.

Further, step S480, composition forms secondary gate electrode in said cell substrate front.

Consult Figure 17; In this embodiment; Can adopt the mode composition of silk screen printing or steel mesh printing to form secondary gate electrode 530; In this process, can select the type and the sintering process of slurry (for example silver slurry), so that forming excellent electrical property with n semiconductor regions 511, secondary gate electrode 530 contacts (for example ohmic contact).Preferably, in this step, also composition forms through hole connecting line 555 (as shown in Figure 2) simultaneously, and secondary gate electrode 530 can adopt identical slurry with through hole connecting line 555.The composition of secondary gate electrode 530, through hole connecting line 555 is provided with requirement can be with reference to Fig. 2 and above related description.

In a further example, the sintering process among above step S450, S460 and the S470 can sintering completion simultaneously behind the secondary gate electrode of printing.

Further, step S490 forms first insulating medium layer in said cell substrate back-patterned.

Consult Figure 18; In this embodiment; Can adopt method compositions such as photoetching, silk screen printing, spraying to form first insulating medium layer, 540, the first insulating medium layers 540 and specifically can be low temperature curing type organic substance material or high temperature sintering type inorganic non-metallic oxide material, for example polyimides (Polyimide; PI), epoxy resin, resistance solder paste China ink etc.Its thickness range can be 2 microns to 100 microns.The composition of first insulating medium layer 540 is provided with requirement can be with reference to Fig. 2, Fig. 7 and above related description.

So far, MWT back of the body contact solar cell 500 shown in Figure 2 basically forms.

Also need to prove, form in secondary gate electrode 530, main grid electrode 550, the back of the body electric field 560 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.

The second embodiment method flow sketch map for preparation solar cell embodiment illustrated in fig. 2 shown in Figure 19.

Contrast Figure 19 and Fig. 9; The preparation method's of the preparation method of second embodiment and first embodiment difference only is to increase step S455; Step S455 is the electrical isolation that is used for realizing main grid electrode 550 and cell substrate 510, forms the structure of the instance shown in Fig. 6 (b).In this embodiment, be different from the mode of spontaneous formation second insulating medium layer 551 of sintering among the step S460 of first embodiment, through in addition separately step S455 composition form.

In step S455, composition forms second insulating medium layer 551 on the cell substrate of desire formation main grid electrode.Particularly; Second insulating medium layer 551 can be formed on the backside surface of inner surface and p semiconductor regions 512 of through hole 590 through the printing composition; Thereby in step S70; When forming main grid electrode 550 with silk screen printing of silver slurry and sintering, the silver slurry directly contact with cell substrate 510, thus realization main grid electrode 550 and cell substrate 510 between electrical isolation.Preferably; The marginal portion of second insulating medium layer 551 extends beyond the contact area of main grid electrode 550 that desire forms and cell substrate (for example the p semiconductor regions 512), prevents main grid electrode 550 direct contact of part and cell substrate (for example the p semiconductor regions 512) on the edge of.The thickness range of second insulating medium layer 551 can be 1 micron-50 microns.

In preparation method's process shown in Figure 19, other process other process basic and Fig. 9 is basic identical, gives unnecessary details no longer one by one at this.

Need to prove that in above Fig. 9 and procedure embodiment illustrated in fig. 19, the formation order between secondary gate electrode and the back of the body electric field is not restrictive, also promptly, step S480 also can accomplish before step S470; In addition, secondary gate electrode 530 also can composition formation again after first insulating medium layer 540 forms, and promptly step S480 also can accomplish after step S490.

Need to prove that also in above Fig. 9 and procedure embodiment illustrated in fig. 19, through hole forms step (being step S420) and also can after step S440 or step S450, accomplish.

Be to be understood that; Although only described main grid electrode and back electrode situation by rows among the above embodiment; Those skilled in the art can design corresponding main grid electrode and back electrode by the solar cell of row arrangement and the embodiment of solar module according to above instruction or enlightenment.

Above example has mainly been explained preparation method and the solar module thereof of MWT of the present invention back of the body contact solar cell, MWT back of the body contact solar cell, the preparation method of solar module.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

1. a metal is characterized in that around wearing type back of the body contact solar cell, comprising:

2. metal as claimed in claim 1 is characterized in that around wearing the type back of the body contact solar cell when said main grid electrode was non-ohmic contact with contacting of said cell substrate, said main grid electrode was 0 slurry printing and sintering formation basically through frit content.

3. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; When being provided with second insulating medium layer between said main grid electrode and the said cell substrate; Said main grid electrode forms through printing of silver slurry and sintering, and said second insulating medium layer is that said silver slurry forms in said sintering process with said cell substrate.

4. metal as claimed in claim 3 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, and said second insulating medium layer is the glass medium layer that forms in the sintering process.

5. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said second insulating medium layer 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 second insulating medium layer extends beyond the contact area of main grid electrode and cell substrate.

6. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell the said main grid electrode of every row/row is by the segmentation setting.

7. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said through hole is provided with on said secondary gate electrode equal intervals ground; M the through hole that lays respectively on the said secondary gate electrode of m bar basically point-blank arranged by row/row, and wherein, m is the integer more than or equal to 3.

8. contact solar cell like claim 1 or 6 or 7 described metals around wearing the type back of the body, it is characterized in that said solar cell also comprises the through hole connecting line that is arranged at said cell substrate front, said through hole connecting line connects the said through hole of arranging by row/row.

9. metal as claimed in claim 8 is characterized in that around wearing type back of the body contact solar cell, on the said through hole connecting line, also be provided with one or more through holes between the adjacent said secondary gate electrode.

10. metal as claimed in claim 8 is characterized in that around wearing the type back of the body contact solar cell live width scope of said through hole connecting line is 100 microns to 1 millimeter.

11. metal as claimed in claim 7 is characterized in that around wearing the type back of the body contact solar cell bar number of said secondary gate electrode is n, n is greater than m, by said m through hole discontinuous arrangement on the secondary gate electrode of n bar of row/row arrangement.

12. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell, in the said main grid electrode hollow out zone is set.

13. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell said back of the body electric field is aluminium or aluminum alloy materials, said back of the body electric field and said first conductivity type regions form ohmic contact.

14. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell said solar cell also comprises the antireflection layer that is formed at said cell substrate front.

15. metal as claimed in claim 1 is characterized in that around wearing the type back of the body contact solar cell silk screen printing simultaneously of said main grid electrode and back electrode or steel mesh printing form.

16. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said first insulating medium layer is banded, and said first insulating medium layer is on the cell substrate between said row/row main grid electrode and the said back of the body electric field and partly cover the edge and the said back of the body electric field of part of said main grid electrode.

17. metal as claimed in claim 16 is characterized in that around wearing the type back of the body contact solar cell width of said first insulating medium layer is greater than the width of said interconnector.

18. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Equidistantly distribute with first spacing between said multirow/row main grid electrode, equidistantly distribute with second spacing between said multirow/row back electrode, said first spacing equals said second spacing.

19. metal as claimed in claim 1 is characterized in that around wearing type back of the body contact solar cell said first insulating medium layer is processed by low temperature curing type organic substance material or high temperature sintering type inorganic non-metallic oxide material.

20. a metal as claimed in claim 1 is characterized in that around the preparation method who wears type back of the body contact solar cell, may further comprise the steps:

Cell substrate with first conductivity type regions is provided;

The location forms through hole in said cell substrate;

Composition forms secondary gate electrode in said cell substrate front; And

Form first insulating medium layer in said cell substrate back-patterned.

21. preparation method as claimed in claim 20 is characterized in that, after forming through hole, also comprises step: said cell substrate is carried out making herbs into wool and cleaning, and remove system formed damage of through hole and residue.

22. preparation method as claimed in claim 20 is characterized in that, carries out also comprising step after the doping of second conduction type: remove phosphorosilicate glass.

23. preparation method as claimed in claim 20 is characterized in that, carries out also comprising step after the doping of second conduction type: deposition antireflection layer in the front of said cell substrate.

24. preparation method as claimed in claim 20 is characterized in that, when composition formed secondary gate electrode, also composition formed the through hole connecting line in said cell substrate front simultaneously.

25. preparation method as claimed in claim 20 is characterized in that, the composition of said main grid electrode, back electrode, back of the body electric field, secondary gate electrode realizes that through silk screen printing or steel mesh printing said main grid electrode, back electrode form through identical slurry.

26. preparation method as claimed in claim 20 is characterized in that, said main grid electrode to form through frit content be that 0 slurry printing and sintering form basically, said main grid electrode is non-ohmic contact with contacting of said cell substrate.

27. preparation method as claimed in claim 20; It is characterized in that; Forming through printing of silver slurry and sintering of said main grid electrode forms, and in said sintering process, is formed on second insulating medium layer between said main grid electrode and the said cell substrate simultaneously.

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 second insulating medium layer is the glass medium layer that forms in the sintering process.

29. preparation method as claimed in claim 20 is characterized in that, this preparation method also comprises step: the composition printing forms said second insulating medium layer on the back side of the inner surface of said through hole and said first conductivity type regions; Wherein, the marginal portion of said second insulating medium layer extends beyond the contact area of main grid electrode and cell substrate.

30. preparation method as claimed in claim 20 is characterized in that, said etching is a wet etching, and said cell substrate floats in the employed etching liquid of wet etching with facing up.

31. solar module; Comprise the solar panel string; It is characterized in that; Said solar panel string comprise a plurality of by row/row arrange like each described metal in the claim 1 to 19 around wearing type back of the body contact solar cell; Connect through interconnector between adjacent two said solar cells in the solar cell of every row/row, every interconnector is connected to the back electrode of corresponding line/row of main grid electrode and another said solar cell of the corresponding line/row of a said solar cell simultaneously on same basically plane, same basically straight line.

32. solar module as claimed in claim 31 is characterized in that, in two the adjacent said solar cells in same delegation/said solar cell of row, one of them said solar cell another said solar cell Rotate 180 degree relatively is provided with.

33. solar module as claimed in claim 31 is characterized in that, being connected to of said interconnector be welded to connect or conductive tape bonding.

34. solar module as claimed in claim 31; It is characterized in that; Said solar module also comprises front light-transmitting substrate, positive face seal adhesive linkage, sealing backside adhesive linkage, back substrate, and said positive face seal adhesive linkage and sealing backside adhesive linkage coat said solar panel string.

35. the preparation method of a solar module as claimed in claim 31 is characterized in that, comprises step:

To arrange by row/row around wearing type back of the body contact solar cell like each described a plurality of metals in the claim 1 to 19;

On same basically plane, connect interconnector.

36. preparation method as claimed in claim 31 is characterized in that, in adjacent two said solar cells, one of them said solar cell is another said solar cell Rotate 180 degree relatively.

37. preparation method as claimed in claim 31 is characterized in that, through being welded to connect or the bonding mode of conductive tape realizes the connection of interconnector.