CN102760777A

CN102760777A - Solar cell, solar cell module and preparation method thereof

Info

Publication number: CN102760777A
Application number: CN2011101100022A
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 cell, a solar cell module and a preparation method thereof, and belongs to the field of photovoltaic technology. A plurality of lines/rows of main gate electrodes, back electric fields, a plurality of lines/rows of back electrodes which are electrically connected to the back electric fields and a first insulation medium layer are disposed on the back of the solar cell. The plurality of lines/rows of main gate electrodes and the plurality of lines/rows of back electrodes are parallel basically. Each line/row of main gate electrodes are arranged symmetrical to a corresponding line/row of back electrodes along a central line, which is parallel with the each line/row of main gate electrodes, of a substrate of the solar cell. The solar cell module comprises a solar cell string. The solar cell string comprises a plurality of the solar cells which are arranged in lines/rows. The solar cell has fine insulated isolation characteristics, is convenient to connect in the solar cell module assembling, and is low in cost. The solar cell module is high in reliability, low in manufacture cost, and high in 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 isolated groove 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 be provided with the preparation method of the MWT back of the body contact solar cell of insulating medium layer, this solar cell, connect a plurality of MWT back of the body contact solar cells through interconnector on same basically plane the solar module and the preparation method of this solar module.

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 application module 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 a layer insulating, and this insulating barrier 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 and second conductivity type regions that are used to form PN junction, and said first conductivity type regions is positioned at the back side of cell substrate, and said second conductivity type regions of part is positioned at the front of cell substrate;

A plurality of through holes, it passes said cell substrate;

Secondary gate electrode, it is arranged at the front of 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 back side of said cell substrate;

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, 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.

According to MWT back of the body contact solar cell provided by the invention, wherein, said solar cell also comprises first isolated groove that is arranged at the said cell substrate back side, and said first isolated groove is used to realize the electrical isolation between said main grid electrode and the said back of the body electric field.

In the above MWT that reaches back of the body contact solar cell; Preferably; Said second conductivity type regions coats said first conductivity type regions basically; The said second conductivity type regions autoregistration counter doping that said back of the body electric field is used for it is contacted forms counterdopant region, and the electric current that said first conductivity type regions is produced exports said back of the body electric field to through said counterdopant region.

Preferably, said first isolation channel is drawn through laser and is carved or the formation of accurate wet etching.

Preferably, the said main grid electrode of every row/row is by the segmentation setting, and every section said main grid electrode is surrounded by said first isolated groove.

In one example, said first isolated groove is filled by said first insulating medium layer.

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 hole between the adjacent said secondary gate electrode.

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

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.

Preferably; Said solar cell also is included in second isolated groove of border area all around said cell substrate front and/or back side formation, that be positioned at said solar cell, and said second isolated groove is used to realize the electrical isolation between said secondary gate electrode and the said back of the body electric field.

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 said back electrode or steel mesh printing form.

Among the embodiment again according to MWT back of the body contact solar cell provided by the invention; 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.

Preferably, equidistantly distribute with first spacing between said multirow/row main grid electrode, equidistantly distribute with second spacing between said multirow/row, 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, a kind of preparation method who prepares the above MWT back of the body contact solar cell 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 second conductivity type regions;

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, and said back of the body electric field is to the said second conductivity type regions autoregistration counter doping that it contacted;

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

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

Preferably,, said cell substrate back-patterned also carries out step before or after forming first insulating medium layer: draw first isolated groove that quarter or accurate wet etching are formed for realizing the electrical isolation between said main grid electrode and the said back of the body electric field through laser.

Preferably, when forming first isolation channel, also draw through laser simultaneously and carve or accurate wet etching border area around the front of said solar cell and/or the back side forms second isolated groove.

Preferably, form after the 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.

According to one side more of the present invention; A kind of solar module is provided; 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.

Particularly, 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 preparation method who prepares the above solar module is provided according to of the present invention, comprises step:

The above a plurality of MWT back of the body contact solar cell that reach is arranged by row/row;

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 the 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 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 100, 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 100.

Fig. 7 is the decomposition texture sketch map of the solar module that provides according to one embodiment of the invention.

Fig. 8 is the method flow sketch map of preparation solar cell embodiment illustrated in fig. 2.

Fig. 9 is extremely shown in Figure 17 to be to change sketch map according to preparation method's structure of process shown in Figure 8.

Figure 18 is the partial schematic diagram according to the cross section structure of the MWT back of the body contact solar cell of further embodiment of this invention.

Figure 19 is the partial schematic diagram according to the cross section structure of the MWT back of the body contact solar cell of yet another embodiment of the invention.

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., the MWT back of the body contact solar cell of this embodiment is elaborated to shown in Figure 5 in conjunction with Fig. 2.

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 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 110 can also be the solar cell basis material of polycrystalline silicon material or other type.The cell substrate 110 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 100) of cell substrate 110, with describing in the solar module thereafter.As shown in Figure 5; In this embodiment; Comprise p semiconductor regions 112 that substrate itself provides in the cell substrate 110 and to the n semiconductor regions 111 of mixing and forming of cell substrate 110, in this example, n semiconductor regions 111 coats said p semiconductor regions 112.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 secondary gate electrode 130 of the electric current of n semiconductor regions through the front (also being the front of cell substrate 110) of solar cell collect and further the main grid electrode 150 through the back side compile and draw, the back of the body electric field 160 of the electric current of p semiconductor regions 112 through solar cell compiles and draws through back electrode 161.

Consult Fig. 2 (b) and Fig. 4, form some secondary gate electrodes 130 on the front 120 of solar cell, routinely; Secondary gate electrode 130 is with the wire setting; The live width of secondary gate electrode 130 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 111 like this; For example, parallel and spaced set between the secondary gate electrode.But the live width of the spacing between the secondary gate electrode 130 and secondary gate electrode 130 itself etc. is not limited by the present invention.Normally; Secondary gate electrode 130 is to starch again with silk screen (or steel mesh) printing conductive silver that high temperature sintering forms; 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 photogenerated current.

For forming MWT back of the body contact solar cell, on the cell substrate of secondary gate electrode 130 corresponding positions, can form the through hole 190 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, thereby main grid electrode 150 can compile and draw the electric current that secondary gate electrode 130 is collected effectively.In this embodiment; Can select wherein to form a plurality of through holes 190 on some secondary gate electrodes 130; Preferably, on many secondary gate electrodes 130 that are arranged in parallel, the layout that is in line in the horizontal of the through hole on the secondary gate electrode 130 of each bar; Many the through hole connecting lines 155 that are basically perpendicular to secondary gate electrode are set on n semiconductor regions 111 surfaces; Through hole connecting line 155 conducting that can (promptly with delegation) through hole point-blank be linked together, therefore, some secondary gate electrode that through hole 190 is not set also can be collected to the main grid electrode 150 at the back side through through hole connecting line 155; So, reduced the position accuracy demand of getting through the hole (when through hole is not arranged on the place, crosspoint of through hole connecting line 155 and secondary gate electrode 130, also can realize the electric connection of secondary gate electrode and back side main grid electrode).Schematically; Be formed with through hole 190 as being provided with altogether among Fig. 2 (b) on 130,28 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 155 be arranged in parallel equally spacedly and with secondary gate electrode 130 square crossings, through hole is arranged on the place, crosspoint of secondary gate electrode 130 and through hole connecting line 155; Correspondingly, shown in Fig. 2 (a), the 150 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 155 is provided with, therefore, corresponding to arranging fully continuously with the non-of the through hole in the delegation; Main grid electrode 150 is divided into 7 sections; By rows, 7 sections of delegation, triplex row altogether.Therefore, through above concrete setting, positive n semiconductor regions 111 electric currents compile with the mode of low relatively series resistance draws.Because through hole connecting line 155 laterally arranges equally spacedly, therefore, triplex row main grid electrode 150 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. are 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 190 can form through methods such as chemical corrosion, mechanical punching, laser drilling, electronic beam drillings.Through hole connecting line 155 can form through modes such as silk screen printings with secondary gate electrode 130, and the width of through hole connecting line 155 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 155), 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) to laterally arrange.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 130 that through hole 190 is set and on through hole connecting line 155; 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 155 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 130 that through hole 190 is set and on through hole connecting line 155, 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 150 in parallel to each other by rows, it can be laterally arranged basically equally spacedly; Main grid electrode 150 comprises back portion 150a and around wearing part 150b, the two all is to form through integrated printing.In this embodiment, n semiconductor regions 111 is formed at the surface and the basic p of the coating semiconductor regions 112 of p semiconductor regions 112.Therefore, main grid electrode 150 is directly to contact (comprising through-hole inner surface and back of solar cell) with n semiconductor regions 111, wherein; Back portion 150a is arranged on the n semiconductor regions 111 at the back side; Be arranged on the n semiconductor regions 111 in the through hole around wearing part 150b, preferably, main grid electrode 150 can form ohmic contact with n semiconductor regions 111; Its contact resistance is lower, more helps drawing compiling of electric current .In other preferred embodiment, hollow out zone (not shown) can be set on the main grid electrode 150, 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.

Back of the body electric field 160 is formed at the back side of solar cell in large area, and it is used to collect and draw the photogenerated current (being the electric current of the p end of pn knot) of p semiconductor regions 112.In this embodiment, back of the body electric field 160 is to be formed directly on the n semiconductor regions 111 that coats p semiconductor regions 112, thereby contacts with local n semiconductor regions 111.Specifically can be through selecting the type of electrode, make them can be to n semiconductor regions 111 counter dopings that it contacted, the metallic element of for example selecting III A bunch is as back of the body electric field material; Preferably, back of the body electric field 160 is aluminium or aluminium alloy, and therefore, aluminium can carry out p type doping (particularly in the metallization processes that forms the aluminium electrode) to the n semiconductor regions 111 that it contacted.Thereby can carry on the back at each and form counterdopant region 180 on the cell substrate of 160 adjacency of electric field.In this embodiment, counterdopant region 180 is the p semiconductor regions, and its p type doping content can be greater than the doping content of p semiconductor regions 112, thereby is easy to and carries on the back electric field 160 form ohmic contact, reduces the contact resistance between electrode 160 and the cell substrate.Need to prove; Counterdopant region 180 and p semiconductor regions 112 normally do not have obvious boundary as shown in Figure 6; This is because with back of the body electric field when mixing in cell substrate as doped source; According to the characteristics of diffusing, doping, doped chemical aluminium can diffuse in the p semiconductor regions 112 always.

In back of the body electric field 160 zones, back electrode 161 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 160 is further led to interconnector.Back electrode 161 is surrounded by back of the body electric fields 160, so the n semiconductor regions of back electrode 161 corresponding contacts are also isolated by additional doped region 180 territories, 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 110 of solar cell is a square, and back electrode 161 also is provided with by row as main grid electrode 150, and one side correspondence of every capable main grid electrode 150 is provided with delegation's back electrode 161.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; 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 111 and every capable main grid electrode symmetry arrangement of cell substrate 110, and center line 111 is parallel to main grid electrode 150.Therefore, also be parallel to each other between every capable back electrode 161, the line number of back electrode 161 (or columns) equates with the line number (or columns) of main grid electrode 150.Normally, single back electrode 161 is generally point-like (being used for being connected with interconnector), and multiple spot back electrode 161 (for example figure shown in 11) is arranged and formed row.When 150 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 160 of a side of main grid electrode 150 can the back electrode 161 through back of the body electric field drainage to its opposite side between the intersegmental crack of main grid electrode.

For isolating in the insulation that realizes main grid electrode 150 on the same solar cell and carry on the back between the electric field 160; The back side at solar cell 100 (also being cell substrate 110) is provided with first insulating medium layer 140; In this embodiment; First insulating medium layer 140 is filled first isolated groove, 145, the first isolated grooves 145 specifically can draw quarter or other method (for example accurate wet etching) formation through laser.First isolated groove 145 can be realized the physical isolation (the n semiconductor regions 111 that separates the back side) of main grid electrode 150 and back of the body electric field 160, thereby also realizes electrical isolation.The concrete setting of first insulating medium layer 140 and effect will be explained in solar module.

It is shown in Figure 6 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. 6 (a) is the arrangement mode sketch map of polylith solar cell 100, 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 100.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. 6, structure of solar panel string 1000 and preparation method thereof is described.

Consult Fig. 6 (a), being connected in series with three solar cells shown in Figure 2 100 forms solar panel string 1000 and carries out schematic illustration.Three solar cells are respectively 100A, 100B, 100C; In this example; At first with they (also can by row) by rows; Wherein, Solar cell 100B is with respect to

solar cell

100A or 100C Rotate 180 degree, thus can be with delegation's main grid electrode of one of them solar cell (for example solar cell 100A) delegation's back electrode of the solar cell (for example solar cell 100B) adjacent align basically point-blank (this be because every capable back electrode 161 along the center line 111 and every capable main grid electrode symmetry arrangement of cell substrate 110) 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. 6 (b), an end of every interconnector 940 wherein delegation's main grid electrode of a solar cell (for example 100A) connects, and its other end connects alignment delegation's back electrode point-blank of another adjacent block solar cell (for example 100B); 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); When adopting welding connecting mode, can use existing welding equipment to accomplish, connection reliability height and equipment requirements are low, so preparation cost is low.Shown in Fig. 6 (b), three interconnectors are welded to connect solar cell 100A and 100B, and it is connected in series the main grid electrode of solar cell 100A and the back electrode of solar cell 100B; Article three, interconnector is welded to connect solar cell 100B and 100C, and it is connected in series the main grid electrode of solar cell 100B and the back electrode of solar cell 100C; 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. 6 and shown in Figure 2, realize above purpose through first insulating medium layer 140, particularly; First insulating medium layer, 140 banded settings; Corresponding every capable main grid electrode 150 is provided with banded first insulating medium layer 140, and the cell substrate zone between main grid electrode 150 and the back of the body electric field 160 is covered by banded first insulating medium layer 140, and first insulating medium layer 140 also partly covers the edge of main grid electrode 150; Cover part back of the body electric field 160 (for example, the edge of the part of the back of the body electric field between the gap of the main grid electrode 150 of overlay segments, back of the body electric field etc.) partly also.One end of interconnector 940 places 150 last times of main grid electrode, first insulating medium layer 140 can realize that back of the body electric field 160 insulation of itself and same solar cell isolate; The other end of interconnector 940 is connected in 161 last times of back electrode, and first insulating medium layer 140 can further reduce the probability of interconnector 940 and main grid electrode 150 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 140.

Structural representation for the solar module that provides according to one embodiment of the invention shown in Figure 7.The solar module of this embodiment comprises the solar panel string 1000 of embodiment as shown in Figure 6, also mainly comprises front light-transmitting substrate 1100, positive face seal adhesive linkage 1200A, sealing backside adhesive linkage 1200B, back substrate 1300.Front light-transmitting substrate 1100, positive face seal adhesive linkage 1200A, solar panel string 1000, sealing backside adhesive linkage 1200B, back substrate 1300 set gradually by under last, and positive face seal adhesive linkage 1200A and sealing backside adhesive linkage 1200B coat solar panel string 1000 basically.Particularly; Front light-transmitting substrate 1100 can be high-intensity armorplate glass;

Sealing adhesive linkage

1200A and 1200B 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 1300 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.

Method flow sketch map for preparation solar cell embodiment illustrated in fig. 2 shown in Figure 8.Fig. 9 is extremely shown in Figure 17 to be to change sketch map according to preparation method's structure of process shown in Figure 8.Preparation method's process of this solar cell is described below in conjunction with Fig. 2, Fig. 8 to Figure 17.

At first, step S10 provides the cell substrate with first conductivity type regions.

Consult Fig. 9, in this embodiment, solar cell is based on cell substrate 110 preparations and forms, and selects p type monocrystalline silicon or polysilicon as cell substrate 110 (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 10ohm Cm, but this is not restrictive, and p type cell substrate 110 can directly be used to form first conductivity type regions 112.By solar light irradiation, cell substrate is chosen as the shape of symmetry structure when solar cell is worked in the front 120 of cell substrate 110, for example, can be square or rectangle.

Further, step S20, the location forms through hole in said cell substrate.

Consult Figure 10, on cell substrate 110, form several through holes 190, through hole 190 penetrates into the back side of cell substrate from the front of cell substrate.Methods such as through hole 190 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 190 in cell substrate can be with reference to Fig. 2 and Fig. 4 and above related description thereof.

Need to prove, after step 20, also generally include step 25 (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 190 is also by formed matte roughening simultaneously, and this helps improving the reliability that slurry is filled.

Further, step S30 carries out the doping of second conduction type to said cell substrate surface.

Consult Figure 11, in this embodiment, the n type is carried out on the surface of cell substrate 110 mix, thereby form n semiconductor regions 111 on cell substrate 110 surfaces.Particularly, can select methods such as diffusing, doping, ion implantation doping.In this step, for reducing cost, need not carry out pattern step such as photoetching in addition to this step of mixing, therefore, in this step of this embodiment, n semiconductor regions 111 is the basic original p semiconductor regions 112 that coat.

Need to prove; For removing the phosphorosilicate glass layer that forms on the cell substrate surface in the doping process; Usually carry out the step (not shown) of removing phosphorosilicate glass later in the doping of second conduction type, wherein, the dephosphorization silex glass can be removed through the method for chemical cleaning.

Further, step S40, deposition antireflection layer in the front of said cell substrate.

Consult Figure 12; In this embodiment, the antireflection layer 113 of positive deposition on the n semiconductor regions, it can pass through methods such as PECVD, LPCVD or APCVD and form; Antireflection layer 113 can be chosen as materials such as silicon nitride, and its concrete thickness range can be the 50-120 nanometer.Through antireflection layer 113 is set, can effectively improve the conversion efficiency of solar cell.

Further, step S50 print filling vias with formation main grid electrode in said cell substrate back-patterned, and printing forms back electrode simultaneously.

Consult Figure 13; In this embodiment, can form main grid electrode 150 and back electrode 161 with the mode composition of silk screen printing or steel mesh printing, in this process; Slurry (for example silver slurry) is filling vias 190 simultaneously, thereby forms the back portion 150a of main grid electrode 150 and around wearing part 150b.Can select type (for example using the filling perforation slurry of specific type) and the sintering process of slurry etc., so that main grid electrode 150 basically forms ohmic contact with n semiconductor regions 110.The particular location layout of main grid electrode 150, back electrode 161 etc. can be with reference to Fig. 2, Fig. 3, Fig. 6 and above related description thereof.

In addition; Preferably; When silk screen printing forms main grid electrode 150, pattern that can also be through half tone is set, when printing forms main grid electrode 150, form some hollow outs zone (not shown), thereby can reduce the contact area of main grid electrode metal and silicon (also being n semiconductor regions 111) 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 S60 forms back of the body electric field in said cell substrate back-patterned.

Consult Figure 14, in this embodiment, back of the body electric field 160 can be through the silk screen printing aluminium paste in cell substrate 110 back sides, and process sequence can be between the formation of formation that forms main grid electrode 150 and secondary gate electrode 130.When selecting aluminium (it belongs to III A bunch metallic element) as back of the body electric field material; Aluminium can carry out the p type to the n semiconductor regions 111 that it contacted and mix (particularly in the metallization processes that forms the aluminium electrode; Sintering process for example); Therefore, meeting forms counterdopant region 180 on the cell substrate of 160 adjacency of each back of the body electric field, thereby back of the body electric field 160 is collected the photogenerated current of p semiconductor regions 112 and reduced to carry on the back the contact resistance of electric field 160 and p semiconductor regions 112.

Further, step 70, composition forms secondary gate electrode in said cell substrate front.

Consult Figure 15; In this embodiment; Can adopt the mode composition of silk screen printing or steel mesh printing to form secondary gate electrode 130; 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 111, secondary gate electrode 130 contacts (for example ohmic contact).Preferably, in this step, also composition forms through hole connecting line 155 (as shown in Figure 2) simultaneously, and secondary gate electrode 130 can adopt identical slurry with through hole connecting line 155.The composition of secondary gate electrode 130, through hole connecting line 155 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 S50, S60 and the S70 can sintering completion simultaneously behind the secondary gate electrode of printing.

Further, step S80, laser draw to carve and form first isolated groove.

Consult Figure 16; In this embodiment; On the n semiconductor regions 111 at the back side of cell substrate; Laser is drawn to carve and is formed first isolated groove 145, and laser isolation channel 145 bottoms arrive p type semiconductor layer 112 at least, thereby realizes the good insulation isolation between main grid electrode 150 and the back of the body electric field 160 with the mode that laser is isolated.First isolated groove 145 surrounds every section main grid electrode 150 and forms.

Preferably; In this step; The method of simultaneously drawing quarter with laser is the etching second isolated groove (not shown) on border area around the front of cell substrate and/or the back side; This second isolated groove forms at the edge of cell substrate, thereby surrounds entire cell substrate face and/or zone, the back side basically, and this insulation that helps realizing carrying on the back between electric field 160 and the secondary gate electrode 130 is isolated.

Further, step S90 forms first insulating medium layer in said cell substrate back-patterned.

Consult Figure 17; In this embodiment; Can adopt method compositions such as photoetching, silk screen printing, spraying to form first insulating medium layer, 140, the first insulating medium layers 140 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 140 is provided with requirement can be with reference to Fig. 2, Fig. 6 and above related description.First insulating medium layer 140 has been filled first isolated groove 145 simultaneously, more helps improving the insulation isolation performance between main grid electrode 150 and the back of the body electric field 160.

So far, MWT back of the body contact solar cell 100 shown in Figure 2 basically forms.

Need to prove that in above procedure, the formation order between secondary gate electrode and the back of the body electric field is not restrictive, also promptly, step S70 also can accomplish before step S60; In addition, secondary gate electrode 130 also can composition formation again after first insulating medium layer 140 forms, and promptly step S70 also can accomplish after step S90.

Shown in Figure 180 is the partial schematic diagram that contacts the cross section structure of solar cell according to the MWT back of the body of further embodiment of this invention.Than Fig. 2, embodiment shown in Figure 5, its main difference is first isolated groove, and the difference that first isolated groove 245 is compared with first isolated groove 145 is that first isolated groove 245 forms through accurate wet etching.Therefore, in preparation method's process shown in Figure 8, preceding through subtract antireflective step (S40) in deposition, accurate wet etching forms first isolated groove 245, can prepare MWT back of the body contact solar cell 200 embodiment illustrated in fig. 18.

Shown in Figure 19 is the partial schematic diagram that contacts the cross section structure of solar cell according to the MWT back of the body of yet another embodiment of the invention.Than Fig. 2, embodiment shown in Figure 5; Its main difference is first isolated groove; The difference that first isolated groove 345 is compared with first isolated groove 145 is; Wherein first isolated groove 345 is not filled first insulating medium layer 140, and also promptly, first insulating medium layer, 140 first composition depositions form and then laser is drawn formation at quarter first isolated groove 345.Therefore, in preparation method's process shown in Figure 8, through the order of transposing step S80 and step S90, promptly first execution in step S90 is execution in step S80 again, can prepare MWT back of the body contact solar cell 300 embodiment illustrated in fig. 19.Other step of preparation MWT back of the body contact solar cell 300 is identical with corresponding other step shown in Figure 8, is not giving unnecessary details one by one at this.

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:

A plurality of through holes, it passes said cell substrate;

Secondary gate electrode, it is arranged at the front of 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; Also comprise first isolated groove that is arranged at the said cell substrate back side, said first isolated groove is used to realize the electrical isolation between said main grid electrode and the said back of the body electric field.

3. according to claim 1 or claim 2 metal is around wearing type back of the body contact solar cell; It is characterized in that; Said second conductivity type regions coats said first conductivity type regions basically; The said second conductivity type regions autoregistration counter doping that said back of the body electric field is used for it is contacted forms counterdopant region, and the electric current that said first conductivity type regions is produced exports said back of the body electric field to through said counterdopant region.

4. metal as claimed in claim 2 is characterized in that around wearing type back of the body contact solar cell said first isolation channel is drawn through laser and carved or the formation of accurate wet etching.

5. metal as claimed in claim 2 is characterized in that around wearing type back of the body contact solar cell said first isolated groove is filled by said first insulating medium layer.

6. metal as claimed in claim 2 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, and every section said main grid electrode is surrounded by said first isolated groove.

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 hole 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.

14. metal as claimed in claim 1 is around wearing type back of the body contact solar cell; It is characterized in that; Said solar cell also is included in second isolated groove of border area all around said cell substrate front and/or back side formation, that be positioned at said solar cell, and said second isolated groove is used to realize the electrical isolation between said secondary gate electrode and the said back of the body electric field.

15. 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.

16. 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.

17. 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.

18. contact solar cell like claim 1 or 17 described metals around wearing the type back of the body, it is characterized in that the width of said first insulating medium layer is greater than the width of said interconnector.

19. 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.

20. 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.

21. 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.

22. preparation method as claimed in claim 21; It is characterized in that, before or after said cell substrate back-patterned forms first insulating medium layer, also carry out step: draw first isolated groove that quarter or accurate wet etching are formed for realizing the electrical isolation between said main grid electrode and the said back of the body electric field through laser.

23. preparation method as claimed in claim 22 is characterized in that, when forming first isolation channel, also draws through laser simultaneously and carves or accurate wet etching border area around the front of said solar cell and/or the back side forms second isolated groove.

24. preparation method as claimed in claim 21 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.

25. preparation method as claimed in claim 21 is characterized in that, carries out also comprising step after the doping of second conduction type: remove phosphorosilicate glass.

26. preparation method as claimed in claim 21 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.

27. preparation method as claimed in claim 21 is characterized in that, when composition formed secondary gate electrode, also composition formed the through hole connecting line in said cell substrate front simultaneously.

28. preparation method as claimed in claim 21 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.

29. 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 20 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.

30. solar module as claimed in claim 29 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.

31. solar module as claimed in claim 29 is characterized in that, being connected to of said interconnector be welded to connect or conductive tape bonding.

32. solar module as claimed in claim 29; 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.

33. the preparation method of a solar module as claimed in claim 29 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 20;

On same basically plane, connect interconnector.

34. preparation method as claimed in claim 33 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.

35. preparation method as claimed in claim 33 is characterized in that, through being welded to connect or the bonding mode of conductive tape realizes the connection of interconnector.