CN112271225A

CN112271225A - Solar cell module and method for manufacturing same

Info

Publication number: CN112271225A
Application number: CN202011272550.0A
Authority: CN
Inventors: 陈登运; 孙俊; 尹丙伟; 石刚; 李岩
Original assignee: Chengdu Yefan Science and Technology Co Ltd
Current assignee: Tongwei Solar Hefei Co Ltd
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2021-01-26

Abstract

The invention relates to a solar cell module and a manufacturing method thereof. The solar cell module includes at least two cell strings and a bus bar. Each cell string comprises a plurality of solar cells provided with a conductive structure. The bus bar spans across the at least two cell strings in the second direction and is in direct contact with the conductive structure of the solar cell sheet at the end of each cell string, and the bus bar is secured together with the individual cell strings by a non-conductive adhesive. The conductive structure may include a positive electrode, a back electrode, a subgrid, a back electric field, a conductive connection, and the like. The invention can avoid the defects of the conventional welding mode and the mode of utilizing the conductive adhesive, for example, the reliability risk of the assembly caused by the failure of the conductive adhesive/solder paste can be greatly reduced, and the defect of incomplete double functions of the adhesion and the conduction of the conductive adhesive is avoided.

Description

Solar cell module and method for manufacturing same

Technical Field

The invention relates to the field of energy, in particular to a solar cell module and a manufacturing method thereof.

Background

With the increasing consumption of conventional fossil energy such as global coal, oil, natural gas and the like, the ecological environment is continuously deteriorated, and particularly, the sustainable development of the human society is seriously threatened due to the increasingly severe global climate change caused by the emission of greenhouse gases. Various countries in the world make respective energy development strategies to deal with the limitation of conventional fossil energy resources and the environmental problems caused by development and utilization. Solar energy has become one of the most important renewable energy sources by virtue of the characteristics of reliability, safety, universality, long service life, environmental protection and resource sufficiency, and is expected to become a main pillar of global power supply in the future.

In a new energy revolution process, the photovoltaic industry in China has grown into a strategic emerging industry with international competitive advantages. However, the development of the photovoltaic industry still faces many problems and challenges, and the conversion efficiency and reliability are the biggest technical obstacles restricting the development of the photovoltaic industry, while the cost control and the scale-up are economically restricted. The photovoltaic module is taken as a core component of photovoltaic power generation, and the development of high-efficiency modules by improving the conversion efficiency of the photovoltaic module is a necessary trend. Various high efficiency modules, such as shingles, half-sheets, multi-master grids, double-sided modules, etc., are currently emerging on the market. With the application places and application areas of the photovoltaic module becoming more and more extensive, the reliability requirement of the photovoltaic module becomes higher and higher, and particularly, the photovoltaic module with high efficiency and high reliability needs to be adopted in some severe or extreme weather frequent areas.

Under the background of vigorous popularization and use of green solar energy, the power loss of the laminated assembly is greatly reduced by utilizing a low-current low-loss electrical principle (the power loss of a photovoltaic assembly is in a direct proportional relation with the square of working current), and the laminated assembly is higher in energy density per unit area by fully utilizing the inter-cell spacing of a battery assembly to lay more batteries for power generation.

In the arrangement of the existing tile-stacked assembly, the mutual connection mode of the bus bar and each solar cell has some defects. In particular, in the existing tile assembly, the bus bars and the solar cells are fixed by a soldering method or via a bonding agent such as conductive adhesive or solder paste.

The soldering method is realized by smearing the soldering flux on the tin-coated copper strip and then soldering the bus bar and the main grid/PAD point on the battery piece at high temperature. The disadvantages of this approach are as follows: the welding temperature is about 370-400 ℃, the heterojunction cell cannot be compatible, and the TCO film and the amorphous silicon layer of the heterojunction cell can be damaged due to high temperature, so that the cell piece fails; the welding shrinkage rates of the welding strip and the battery piece are different under the high-temperature condition, and the risk of cracking is large; the surface of the bus bar must be coated with a tin layer, so that the cost is high and the production process is complex.

The method using the conductive adhesive or the solder paste and other adhesives has the following disadvantages: the dual functions of adhesion and conduction lead to higher material requirements, and the reliability risks in consideration of the two functions; the conductive adhesive is expensive, so that the use cost is high; the spraying precision requirement of the production process and equipment is high, and the short circuit risk caused by glue overflow exists.

It is therefore desirable to provide a solar cell module and a method of manufacturing the same that at least partially solves the above problems.

Disclosure of Invention

The invention aims to provide a solar cell module and a manufacturing method thereof. The connection mode of the solar cell pieces and the bus bar in the invention is different from the traditional welding mode or the mode of utilizing adhesives such as conductive adhesive or tin paste, and the bus bar of the solar cell module in the invention is directly contacted with the conductive structure of each solar cell piece and is fixed with each solar cell piece through the non-conductive adhesives. The invention can avoid the defects of the conventional welding mode and the mode of utilizing the conductive adhesive, for example, the reliability risk of the assembly caused by the failure of the conductive adhesive/solder paste can be greatly reduced, and the defect of incomplete double functions of the adhesion and the conduction of the conductive adhesive is avoided. And moreover, the risk of glue overflow of the conductive adhesive can be avoided, the assembly cost is greatly reduced, and the possibility of cracking caused by welding stress is avoided. In addition, the bus bar is not provided with the tin layer, so that the cost can be further reduced.

The fixing of the binding agent between the bus bar and the solar cell is realized by adopting a low-temperature curing mode, the mode can be applied to various solar cells such as heterojunction solar cells and the like, the solar cell module can also be various modes such as a laminated module, a conventional module or a half-module and the like, and the solar cell can be not provided with structures such as a main grid line, a welding disc and the like.

According to a first aspect of the present invention, there is provided a solar cell module comprising:

the solar cell comprises at least two cell strings, wherein each cell string comprises a plurality of solar cells which are sequentially arranged along a first direction and are connected together in a conductive manner, a conductive structure is arranged on the surface of each solar cell, all the cell strings are arranged along a second direction which is perpendicular to the first direction, and the first direction and the second direction are both parallel to the extending direction of each solar cell;

and the bus bars span all the cell strings in the second direction and are in direct contact with the conductive structure of the solar cell sheet at the end part of each cell string, and the bus bars are fixed together with the cell strings through non-conductive adhesives.

In one embodiment, a non-conductive adhesive is applied at the location where the bus bars and the conductive structures of the solar cell sheet at the end of each cell string are in direct contact.

In one embodiment, each solar cell sheet includes a grid line disposed on a surface of the solar cell sheet, and the bus bar is in direct contact with the grid line of the solar cell sheet at an end of each cell string.

In one embodiment, the grid lines of each solar cell include a plurality of sub-grid lines and a main grid line in contact with each sub-grid line, and the bus bar is in direct contact with the main grid line or the sub-grid line of the solar cell at the end of each cell string.

In one embodiment, each solar cell includes a grid line disposed on a surface of the solar cell and a conductive connection portion connected to the grid line, and the bus bar is in direct contact with the conductive connection portion of the solar cell at an end of each cell string.

In one embodiment, the grid line of each solar cell comprises a plurality of sub-grid lines and a main grid line in contact with each sub-grid line, wherein:

each main grid line is a linear type main grid line, a plurality of conductive connecting parts are arranged on the linear type main grid lines, and the width of each conductive connecting part is larger than that of each linear type main grid line; or

Each main grid line comprises two parallel linear main grid lines, and a plurality of conductive connecting parts are connected between the two linear main grid lines and are arranged along the extending direction of the two linear main grid lines; or

Each conductive connection portion is disposed across more than two finger lines.

In one embodiment, the bottom surface of each solar cell sheet is provided with a back field, and the bus bars are in direct contact with the portions of the solar cell sheets at the ends of each cell string forming the back field.

In one embodiment, the bottom surface of each solar cell is provided with a back field on which a plurality of conductive connections are provided, the bus bars being in direct contact with the conductive connections of the solar cells at the end of each cell string.

In one embodiment, the non-conductive adhesive is a dot structure made of acrylic resin, silicone resin, epoxy resin, or polyurethane.

In one embodiment, the bus bar is a continuous strip structure made of tin-plated copper or copper foil.

In one embodiment, the surface of the bus bar is not provided with a tin layer.

In one embodiment, in each cell string, the solar cells are arranged in a shingled manner, and adjacent solar cells are electrically connected through direct contact of the conductive structure; or

In each cell string, the solar cells are distributed in a tiled mode, and the solar cells are connected together in a conductive mode through the solder strips, wherein the solar cells are whole solar cells or half solar cells.

According to a second aspect of the present invention, there is provided a method of manufacturing a solar cell module, the method comprising the steps of:

arranging a plurality of solar cells, wherein each solar cell is provided with a conductive structure;

setting at least two battery strings, wherein the step of setting the at least two battery strings comprises the following steps:

arranging a plurality of solar cells along a first direction and connecting the solar cells together in a conductive manner to form each cell string;

arranging at least two cell strings along a second direction perpendicular to the first direction, wherein the first direction and the second direction are both parallel to the extending direction of each solar cell;

arranging the bus bars such that the bus bars span all the cell strings in the second direction and are in direct contact with the conductive structure of the solar cell sheet at the end of each cell string;

applying a non-conductive adhesive between the bus bar and each of the battery strings, and curing the non-conductive adhesive at a temperature of less than 200 ℃.

In one embodiment, the step of applying the non-conductive adhesive comprises: a non-conductive adhesive is applied at locations where the bus bars are in direct contact with the conductive structures of the solar cell sheet at the end of each cell string.

In one embodiment, the step of providing a plurality of solar cells includes: applying grid lines on the surface of a large cell piece forming a plurality of solar cell pieces;

the step of providing the bus bar includes: so that the bus bars are in direct contact with the grid lines of the solar cell sheet at the end of each cell string.

In one embodiment, for each solar cell, the grid lines comprise a plurality of secondary grid lines and a main grid line in contact with each secondary grid line; the step of providing the bus bar includes: so that the bus bars are in direct contact with the sub-grid lines or the main grid lines of the solar cell pieces at the end of each cell string.

In one embodiment, the step of providing a plurality of solar cells includes: applying grid lines on the surface of a large cell piece forming a plurality of solar cell pieces; conductive connecting parts connected with the grid lines are applied on the surface of the large sheet of the battery piece,

the step of providing the bus bar includes: so that the bus bars are in direct contact with the conductive connections of the solar cell sheets at the ends of each cell string.

In one embodiment, the step of providing a plurality of solar cells includes: arranging a back electric field on the bottom surface of a cell sheet of the plurality of solar cell sheets;

the step of providing the bus bar includes: so that the bus bars are in direct contact with the portions of the solar cells at the ends of each cell string where the back electric field is disposed.

In one embodiment, the step of providing a plurality of solar cells includes: arranging a back electric field on the bottom surface of a large cell piece forming a plurality of solar cell pieces, and arranging a conductive connecting part on the back electric field;

In one embodiment, acrylic, silicone, epoxy, or polyurethane is selected as the conductive binder.

In one embodiment, a curing agent, a crosslinking agent, a coupling agent, or rubber balls are added to the material used to make the adhesive.

In one embodiment, tin-plated copper or copper foil is selected for making the bus bar.

In one embodiment, the method does not include the step of providing a tin layer on the surface of the bus bar.

In one embodiment, the step of providing each battery string comprises: arranging all solar cells in a shingled manner, and realizing conductive connection between adjacent solar cells through direct contact of a conductive structure; or

The step of setting each battery string includes: the solar cell pieces are distributed in a tiled mode, so that the solar cell strings are connected together in a conductive mode through the solder strips, wherein the solar cell pieces are whole solar cell pieces or half solar cell pieces.

Drawings

For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. Like reference numerals in the drawings refer to like parts. It will be appreciated by persons skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention without any limiting effect on the scope of the invention, and that the various components in the drawings are not drawn to scale.

Fig. 1 is a schematic top surface view of a solar cell module according to a preferred embodiment of the present invention, in which only the outline of each solar cell sheet is shown, and a grid line structure on the top surface of each solar cell sheet is not shown;

FIG. 2 is an enlarged view of a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a cross-sectional view taken along line B-B of FIG. 1;

FIG. 4 is a cross-sectional view taken along line C-C of FIG. 1;

fig. 5 is a schematic top surface view of a solar cell module according to another preferred embodiment of the present invention, in which only the outline of each solar cell sheet is shown, and the grid line structure on the top surface of each solar cell sheet is not shown;

fig. 6 is a schematic bottom surface view of a portion of the terminal solar cell sheet and bus bar of one of the cell strings of fig. 5;

fig. 7 is a schematic view after applying a non-conductive tape over the terminal solar cell sheet and bus bar in fig. 6;

FIG. 8 is a cross-sectional view taken along line E-E in FIG. 5;

FIG. 9 is an alternative view of FIG. 6;

FIG. 10 is a view taken along line F-F in FIG. 9 and after being flipped 180 in a clockwise direction into the page;

FIG. 11 is an alternative view of FIG. 10;

fig. 12 is a schematic top surface view of a solar cell module according to a third embodiment of the present invention;

fig. 13 is a schematic top surface view of a solar cell module according to a fourth embodiment of the present invention.

Reference numerals:

solar cell module

100, 200, 300, 400

Battery strings

1, 4, 7, 401

Solar cells

11, 41, 71

Half solar cell 402

Head end

solar cell

12, 42, 72

End

solar cell sheets

13, 43', 73

Positive electrode 101

Back electrode

102, 202

Top bus bar

2, 5, 8, 403

Bottom bus bar

3, 6', 9, 404

Conductive connection parts

23, 33 "

Back electric field 202'

Sub-grid line 203

Nonconductive tape 7

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. What has been described herein is merely a preferred embodiment in accordance with the present invention and other ways of practicing the invention will occur to those skilled in the art and are within the scope of the invention.

In the present invention, a solar cell module and a method for manufacturing the same are provided, and fig. 1 to 4 show a structure according to a first embodiment of the present invention; fig. 5 to 11 show a structure according to a second embodiment of the present invention; fig. 12 shows a structure according to a third embodiment of the present invention; fig. 13 shows a structure according to a fourth embodiment of the present invention.

It is first noted that the directional terminology referred to herein is for purposes of illustration only and not of limitation, the first direction referred to herein being shown, for example, in the figures as D1; the second direction referred to herein is illustrated, for example, by D2 in the figures; the height direction of the solar cell sheet mentioned herein may also be understood as the thickness direction of the solar cell sheet, which is shown by D3 in the drawings; the first direction D1, the second direction D2, and the height direction D3 are orthogonal to each other in space.

Reference is first made to fig. 1-4. In the first embodiment of the present invention, the solar cell module 100 includes three cell strings 1 arranged in the second direction D2, and each cell string 1 includes, for example, 8 solar cell sheets 11 along the first direction D1 perpendicular to the second direction D2. In other embodiments, the solar cell module 100 may include two or more cell strings 1, and the number of the solar cells 11 in each cell string 1 is not limited to 8. The respective cell strings 1 may have a gap therebetween (as shown in fig. 1) or may be closely adjacent so as not to have a gap.

Each solar cell 11 in each cell string 1 is provided with a conductive structure, and in this embodiment, the conductive structure may include a grid line structure disposed on the surface of the solar cell 11.

The solar module 100 also includes two bus bars — a top bus bar 2 and a bottom bus bar 3. The bus bars span all the cell strings 1 in the second direction D2 and are in direct contact with the conductive structure of the solar cell sheet 11 at the end of each cell string 1, and the bus bars are fixed together with the respective cell strings 1 by a non-conductive adhesive.

For convenience of description, the solar cell pieces 11 at both end portions of each cell string 1 are referred to as a head-end solar cell piece 12 and a tail-end solar cell piece 13, but it is understood that the head-end solar cell piece 12, the tail-end solar cell piece 13, and the other solar cell pieces 11 within the cell string 1 differ only in position, and may be identical in other aspects of structure and the like.

In the present embodiment, the solar cell module 100 is a laminated module, and the solar cells 11 in each cell string 1 are connected to each other in a laminated manner. Referring to fig. 2, the grid line structure of each solar cell sheet 11 includes a positive electrode 101 and a back electrode 102, and when two adjacent solar cell sheets 11 are interconnected in a shingled manner, the positive electrode 101 of one solar cell sheet 11 and the back electrode 102 of the other solar cell sheet 11 are aligned and contacted in the height direction D3 to achieve conductive connection of the two solar cell sheets 11. In the present embodiment, the surface of the solar cell sheet 11 is also provided with the sub-grid lines, but the sub-grid lines are not shown in the figure. Specifically, a plurality of sub-grid lines extending in the first direction D1 are disposed on the top surface of each solar cell sheet 11, and the positive electrode 101 is in contact with each sub-grid line to collect the current of the sub-grid line. When the solar cell pieces 11 are double-sided solar cell pieces 11, the bottom surface of each solar cell piece 11 may also be provided with sub-grid lines, and the back electrode 102 contacts the sub-grid lines to collect the current of the sub-grid lines.

Referring to fig. 1 to 3, it can be seen that the top bus bar 2 of the solar cell module 100 is disposed at the edge of the top surface of each cell string 1 along the second direction D2 and is in conductive contact with the positive electrode 101 of the head-end solar cell sheet 12 of each cell string 1, and the top bus bar 2 is formed in a complete bar-shaped structure.

Further, a nonconductive adhesive is applied to a position where the top bus bar 2 directly contacts the positive electrode 101 of each head solar cell sheet 12, the nonconductive adhesive is pressed between the top bus bar 2 and the positive electrode 101 of each head solar cell sheet 12, and the nonconductive adhesive may have a dot structure uniformly arranged along the second direction D2.

Referring to fig. 4, the bottom bus bar 3 of the solar cell module 100 is disposed at the bottom surface edge of each cell string 1 along the second direction D2 and is in conductive contact with and fixed together with the back electrode 102 of the terminal solar cell piece 13 of each cell string 1. Wherein a non-conductive adhesive is applied to a position where the bottom bus bar 3 directly contacts the back electrode 102 of each end solar cell 13, the non-conductive adhesive is pressed between the bottom bus bar 3 and the back electrode 102 of each end solar cell 13, and the non-conductive adhesive may be a dot structure uniformly arranged along the second direction D2. The bottom bus bar 3 is formed in a complete bar structure.

In manufacturing the solar cell module 100, the non-conductive adhesive may be applied to each electrode and then the bus bars may be printed such that the non-conductive adhesive is embedded in the bus bars. A specific manufacturing process of the solar cell sheet 100 will be described in detail later.

Further, in addition to the bus bar being able to contact the electrode of the solar cell, an electrically conductive connection for better electrically conductive connection with the bus bar may be additionally provided, the electrically conductive connection may have a better electrical conductivity than the grid line, and the electrically conductive connection may be made of, for example, aluminum. The conductive connection portion is configured to be in conductive contact with the gate line (the main gate line and/or the sub gate line), and the bus bar is in direct contact with the conductive connection portion. That is, in the case where the conductive connection part is present, the "conductive structure" of the solar cell sheet for direct contact with the bus bar may include the conductive connection part. The conductive connection may also be referred to as a pad point or pad.

For example, referring to fig. 3, the positive electrode 101 is a straight-line-shaped main grid line, the plurality of conductive connection portions 23 are arranged on the straight-line-shaped main grid line, and the width of the conductive connection portions 23 (i.e., the dimension in the direction perpendicular to the paper surface in fig. 3) is larger than the width of the straight-line-shaped main grid line. The top bus bar 2 can be in conductive contact with the positive electrode 101 and the conductive connection portion 23 at the same time, and the conductive connection portion 23 is more conductive than the positive electrode 101.

In addition to the structure shown in fig. 3, each positive electrode may further include two parallel linear bus bars, and a plurality of conductive connection portions may be connected to the linear bus bars directly and arranged along the extending direction of the two linear bus bars. The top bus bar can be in conductive contact with the two linear main grid lines and the conductive connecting part at the same time, and the top bus bar can also be in conductive contact with the two linear main grid lines only.

Similarly, referring to fig. 4, the back electrode 102 may be a straight-line-type bus bar, the plurality of conductive connection portions 23 are arranged on the straight-line-type bus bar, and the width of the conductive connection portions 23 (i.e., the dimension perpendicular to the paper surface in fig. 4) is greater than the width of the straight-line-type bus bar. The bottom bus bar 3 can be in conductive contact with the back electrode 102 and the conductive connection portion 23 at the same time, and the conductive connection portion 23 is more conductive than the back electrode 102.

In addition to the structure shown in fig. 4, each of the back electrodes may further include two parallel linear bus bars, and a plurality of conductive connection portions may be connected to the linear bus bars directly and arranged along the extending direction of the two linear bus bars. The bottom bus bar can be in conductive contact with the two linear main grid lines and the conductive connecting part at the same time, and the bottom bus bar can also be in conductive contact with the two linear main grid lines only.

In embodiments where a non-conductive connection is provided, care should be taken to bypass the conductive connection when applying the non-conductive adhesive.

Preferably, the top and bottom bus bars 2 and 3 are made of tin-plated copper or copper foil without any treatment, and the top and bottom bus bars 2 and 3 may have various shapes, thicknesses, and widths. Also preferably, the non-conductive adhesive may be made of acrylic resin, silicone resin, epoxy resin, or polyurethane, and the non-conductive adhesive is doped with a curing agent, a cross-linking agent, a coupling agent, or rubber balls in order to form a certain thickness.

Preferably, before the bus bars are arranged, a non-conductive adhesive may be sprayed or printed on the electrodes of each of the head end solar cell sheet 12 and the end solar cell sheet 13, and then the bus bars are bonded to the corresponding positions, and the adhesive is cured at a temperature of less than 200 °. The post-curing lamination step provides a tighter and more uniform fit between the bus bar and the corresponding electrode.

Fig. 5-11 show a second embodiment according to the invention. In the present embodiment, the solar cell module 200 is still a stack module, and for the sake of simplicity, the same or similar portions as those in the first embodiment may be omitted from the description.

In the present embodiment, the conductive structure of the solar cell sheet 41 includes a positive electrode disposed on the top surface and the finger lines 203 and the back electrode 202 disposed on the bottom surface.

Referring to fig. 6, a plurality of finger lines 203 on the bottom surface of the solar cell sheet 43 extend in the first direction D1 and are sequentially arranged in the second direction D2, and a back electrode 202 is disposed at the bottom surface of the longitudinal edge of the solar cell sheet 43 and is in conductive contact with each finger line 203.

Referring to fig. 6 and 8, in the present embodiment, the bottom bus bar 6 is in conductive contact with the sub-grid lines 203 of the solar cell sheets 43 each in contact therewith. Also, a non-conductive adhesive is further applied at the position where the bottom bus bar 6 and the finger line 203 of each end solar cell 43 directly contact. The non-conductive adhesive is formed in a plurality of dot-like structures arranged in the second direction D2 and is pressed between the bottom bus bar 6 and the base sheet of each of the terminal solar cell sheets 43.

Preferably, before the bottom bus bar 6 is disposed, a non-conductive adhesive may be sprayed or printed on the region of each end solar cell sheet 43 where the subgrid 203 is disposed, and then the bottom bus bar 6 is bonded to the end solar cell sheet 43 and the adhesive is cured at a temperature of less than 200 °.

In addition to or instead of the non-conductive adhesive, a non-conductive tape may be used to secure the bus bar and the solar cell sheet together. Specifically, in the case where a nonconductive adhesive is applied between the bus bar and the solar cell sheet, a nonconductive tape may be simultaneously provided to fix the bus bar and the solar cell sheet together; alternatively, in the case where a nonconductive adhesive is not applied between the bus bar and the solar cell sheet, a nonconductive tape may be directly applied to the bus bar and the solar cell sheet after the bus bar and the solar cell sheet are accurately positioned to fix the bus bar and the solar cell sheet together. For example, fig. 8 shows a scheme of providing the non-conductive tapes 7 on the end solar cell sheet 43 and the bottom bus bar 6 in fig. 6, the non-conductive tapes 7 may be one or more, each non-conductive tape 7 extends substantially in a direction perpendicular to the bottom bus bar 6 and directly covers the bottom surface of the bottom bus bar 6 while being in direct contact with the bottom surface of the end solar cell sheet 43.

The non-conductive adhesive tape 7 shown in fig. 8 can also be applied to other embodiments. For example, in embodiments where the bus bars are in direct contact with the bus bars and the bus bars, in embodiments where the bus bars are in direct contact with the back field, and in embodiments where the bus bars are in direct contact with the conductive connection portions, a non-conductive adhesive tape may be provided that directly covers the surfaces of the bus bars and the solar cell sheet, respectively, to secure the bus bars and the solar cell sheet together.

Further, referring to fig. 8, a plurality of conductive connection portions 33 are further disposed on the bottom surface of the terminal solar cell 43, and each conductive connection portion 33 is disposed to cross at least two sub-grid lines 203. The bottom bus bar 6 can be in conductive contact with the finger 203 and the conductive connection 33 at the same time, and the conductive connection 33 is more conductive than the finger 203.

It should be noted that, the manner that the bus bar is in conductive contact with the grid lines (including the main grid lines and the sub grid lines) and the conductive connecting parts at the same time is preferable, because the manner utilizes the conductivity of the grid lines and the conductive connecting parts at the same time, and the arrangement can enhance the conductivity between the solar cell and the bus bar, so that the bus bar can be more effectively subjected to bus bar.

Fig. 9 is an alternative embodiment of the arrangement shown in fig. 6, and fig. 10 is a bottom surface view of the terminal solar cell sheet 43 'and a portion of the bottom bus bar 6' in the cell string shown in fig. 9 disposed at the end along the second direction D2. In order to maintain the same shape in the height direction D3 of each sectional view, fig. 10 is a view taken along the line F-F in fig. 9 and after being turned 180 ° in the paper, and thus "top" and "bottom" shown in fig. 10 correspond to "top" and "bottom" shown in fig. 8.

The back field 202 'is disposed on the bottom surface of the solar cell 43' over a large area, and the bottom bus bar 6 'only needs to be in contact with the back field 202'. That is, the bus bars do not have to be aligned to narrow electrodes, and thus such an arrangement is highly tolerant of alignment accuracy, allowing for some degree of angular and positional shifting of the bus bars. For example, the bottom bus bar 6 ' may be disposed at an intermediate position of each of the end solar cell sheets 43 ' in the first direction D1, and the bottom bus bar 6 ' need not extend to the end of all the cell strings in the second direction D2 in the second direction D2.

Referring to fig. 9 to 10, the solar cell in this embodiment is a single-sided solar cell, and the bottom surface of the single-sided solar cell is not provided with the sub-grid lines but is provided with a back electric field 202 ', such as an aluminum back field, and a back electrode (the back electrode is not shown in the figure) may be further provided on the back electric field 202'. The bottom bus bar 6 ' is in direct contact with the back field 202 ' of the end solar cell 43 ' to be electrically connected. Similarly, the bottom bus bar 6 'and the back field 20' 2 may be secured together by a non-conductive adhesive. Preferably, before the bottom bus bar 6 'is disposed, a non-conductive adhesive may be sprayed or printed on the back field 202' of each end solar cell 43 ', and then the bottom bus bar 6' is attached to the back field 202 and the adhesive is cured at a temperature of less than 200 °. The lamination step after curing allows the bottom bus bar 6 'to conform more closely and uniformly to the back field 202', which is suitable for single sided batteries.

Fig. 11 shows an alternative embodiment of fig. 10. In the embodiment shown in fig. 11, the conductive connection 33 is applied to the back field 202 "of the terminal solar cell 43", and the bottom bus bar 6 "and the conductive connection 33" are in direct contact. The conductivity of the conductive connection 33 "is stronger than that of the back electric field 202". In the embodiment shown in fig. 11, care should be taken to bypass the conductive connection 33 "when applying the non-conductive adhesive.

Note that the above-described manner of disposing the bus bars at the non-edge positions of the solar cell sheet is applicable only to the bottom bus bars and not to the top bus bars. Since the solar cell generally requires the top to receive light, the top bus bar needs to be disposed at the edge of the solar cell. More preferably, the bottom bus bar is also preferably disposed at the edge.

Also, various ways of providing the bus bars shown in fig. 1 to 11 may be used in combination. For example, for a solar cell module comprising a single-sided solar cell sheet: the top bus bar may also be in conductive contact with the positive electrode and/or the conductive connection of the solar cell sheet; the bottom bus bar may be in conductive contact with the back field and the conductive connection of the solar cell, and in the presence of the back electrode, the bottom bus bar may also be in conductive contact with the back electrode and/or the conductive connection of the solar cell. For solar cell modules comprising bifacial solar cells, the top bus bar may also be in conductive contact with the positive electrode of the solar cell; the bottom bus bar can be in conductive contact with the bottom surface secondary grid line of the solar cell, and the bottom bus bar can also be in conductive contact with the back electrode of the solar cell (.

Fig. 12 shows a schematic view of a solar cell module according to a third embodiment of the present invention.

The solar cell module 300 shown in fig. 12 is not a shingled module, but a conventional solar cell module in which individual solar cells are tiled. In each cell string 7, the plurality of solar cells 71 are tiled along the first direction D1, and a conductive structure such as a grid line structure, an electric field, etc. may be disposed on each solar cell 71. Each cell string 7 further comprises a conductive solder ribbon 74, and the conductive solder ribbon 74 electrically connects the conductive structures of the respective solar cells 71. The structure of the conductive solder strip 74 shown in fig. 12 is merely illustrative, and in practice the conductive solder strip will have a more complex structure than that shown in fig. 12. For example, in practice, each pair of adjacent solar cells may collectively correspond to a conductive solder strip extending from the bottom surface of one of the pair of adjacent solar cells to the top surface of the other of the pair of adjacent solar cells, thereby conductively connecting the two solar cells.

In the present embodiment, the arrangement of the top bus bar 8 and the bottom bus bar 9 may be similar to the embodiment shown in fig. 1 to 11. Specifically, the top bus bar 8 may be in conductive contact with the positive electrode on the top surface of each head end solar cell sheet 72; the bottom bus bars 9 may be in conductive contact with conductive structures (e.g., grid line structures or back electric fields) on the bottom surface of each terminal solar cell piece 73.

The respective cell strings 7 may have a gap therebetween (as shown in fig. 12) or may be closely adjacent so as not to have a gap; the individual solar cells 71 in each cell string 7 may have gaps therebetween (as shown in fig. 12) or may be closely adjacent without gaps.

In embodiments such as shown in fig. 13, each of the full-sheet solar cells shown in fig. 11 may also be replaced with a half-sheet solar cell 402 to form a half-sheet assembly. The solar cell module 400 formed as a half-sheet module includes a plurality of cell strings 401, each cell string 401 includes a half-sheet solar cell 402, a top bus bar 403 of the half-sheet module 400 is in direct contact with a positive electrode of a leading solar cell of each cell string 401, and a bottom bus bar 404 of the half-sheet module 400 is in direct contact with a conductive structure of a trailing solar cell of each cell string 401.

The individual cell strings 401 may have gaps between them (as shown in fig. 13) or may be closely adjacent so as not to have gaps; the individual solar cells 402 in each cell string 401 may have gaps (as shown in fig. 13) or may be closely adjacent without gaps.

Embodiments provided herein also include methods for fabricating a solar cell module as shown in fig. 1-13. The method specifically comprises the following steps: arranging a plurality of solar cells, wherein each solar cell is provided with a conductive structure; setting at least two battery strings, wherein the step of setting the at least two battery strings comprises the following steps: arranging and electrically connecting a plurality of solar cells along a first direction D1 to form each cell string; at least two cell strings are arranged along a second direction D2 perpendicular to the first direction D1, and both the first direction D1 and the second direction D2 are parallel to the extending direction of each solar cell.

The method further comprises the following steps: arranging the bus bars such that the bus bars span across at least two cell strings in the second direction D2 and are in direct contact with the conductive structure of the solar cell sheet at the end of each cell string; applying a non-conductive adhesive between the bus bar and each of the battery strings, and curing the non-conductive adhesive at a temperature of less than 200 ℃.

Wherein the step of applying the non-conductive adhesive comprises: a non-conductive adhesive is applied at locations where the bus bars are in direct contact with the conductive structures of the solar cell sheet at the end of each cell string. This step can be achieved by means of dispensing or screen printing. Specifically, the dispensing method is suitable for a scheme of connecting the bus bar and the sub-gate line or the back electric field.

The step of arranging a plurality of solar cells comprises the following steps: applying grid lines on the surface of the solar cell; the step of providing the bus bar includes: so that the bus bars are in direct contact with the grid lines of the solar cell sheet at the end of each cell string. Specifically, for each solar cell, the grid lines comprise a plurality of auxiliary grid lines and main grid lines in contact with each auxiliary grid line; the step of providing the bus bar includes: so that the bus bars are in direct contact with the sub-grid lines or the main grid lines of the solar cell pieces at the end of each cell string.

The step of providing a plurality of solar cells may include: arranging a back electric field on the bottom surface of the solar cell; the step of providing the bus bar includes: so that the bus bars are in direct contact with the portions of the solar cells at the ends of each cell string where the back electric field is disposed.

In the above method, acrylic resin, silicone resin, epoxy resin or polyurethane may be selected as the conductive adhesive, and in order to form a certain thickness, a curing agent, a cross-linking agent, a coupling agent or rubber balls may be doped therein; in the above method, the bus bar may be made of tin-plated copper or copper foil.

Also, preferably, the above method does not include a step of providing a tin layer on the surface of the bus bar.

In the above method, the solar cell module may be provided as a stack module, or may be provided as a conventional module or a half-module. That is, the step of setting each battery string may include: the solar cells are arranged in a shingled mode, and the adjacent solar cells are in conductive connection through direct contact of the conductive structure. The step of setting each battery string may also include: the solar cell pieces are distributed in a tiled mode, so that the solar cell strings are connected together in a conductive mode through the solder strips, wherein the solar cell pieces are whole solar cell pieces or half solar cell pieces.

The method described above also has other set-up steps. For example, a method of manufacturing a solar cell module mainly includes the steps of: arranging a large substrate sheet; printing a grid line on a large substrate sheet; an intermediate treatment step; and splitting the cell into a plurality of solar cells in a large scale.

Wherein each step may have a variety of preferred settings. For example, the step of providing a larger sheet of substrate may comprise: and arranging the substrate sheet large sheet, wherein the substrate sheet large sheet comprises a plurality of substrate sheet units which are connected together, and after the cell large sheet is split, each substrate sheet unit forms a substrate sheet of the solar cell sheet, and each substrate sheet unit has two longitudinal edges and two transverse edges. The step of providing a larger sheet of substrate may further comprise the steps of: arranging a monocrystalline silicon wafer; preparing wool and cleaning residual liquid during wool preparation; introducing phosphorus oxychloride to form a PN junction on the surface of the monocrystalline silicon wafer; etching and removing phosphorosilicate glass; high temperature oxidation to form silicon dioxide layers on the top and bottom surfaces of the single crystal silicon wafer; forming an aluminum oxide film on the surface of the silicon dioxide layer; forming a silicon nitride film on the surface of the aluminum oxide film, thereby generating a large substrate sheet; and laser grooving is carried out on the bottom surface of the large substrate sheet.

The method also comprises the following steps before splitting: and confirming whether the front and back surfaces of the large battery piece are preset surfaces or not, and if the front and back surfaces are the preset surfaces, controlling the mechanical arm to turn over the large battery piece by the control mechanism.

Wherein the step of printing the gate line may include: printing top surface grid lines on the top surface of the base sheet large sheet, and printing bottom surface grid lines on the bottom surface of the base sheet large sheet, wherein the printing directions of the top surface grid lines and the bottom surface grid lines are such that when two solar cell sheets are arranged in a tiling mode, the bottom surface grid lines of a first solar cell sheet in the two solar cell sheets and the top surface grid lines of a second solar cell sheet in the two solar cell sheets are in cross contact to realize electric connection.

Intermediate processing steps may include, for example, sintering, passing through a light decay oven or an electrical injection oven, reducing cell light decay, test grading, etc.

Subsequent processing steps after the solar cell is split may include: arranging all solar cells into cell strings in a tiling mode, assembling the cell strings, automatically typesetting and converging the strings, laying an adhesive film and a back plate, detecting, laminating, trimming, framing, connecting a middle junction box, curing, cleaning, testing and the like to finish packaging of the solar cell module.

The various steps described above may be further expanded. For example, in a complete manufacturing process, the following steps may be included: a single crystal silicon wafer is adopted to obtain a good suede structure through surface texturing, so that the specific surface area is increased, more photons (energy) can be received, and the reflection of incident light is reduced; the residual liquid during the texturing is cleaned, so that the influence of acidic and alkaline substances on the battery knot making is reduced; phosphorus oxychloride reacts with the silicon wafer to obtain phosphorus atoms. After a certain time, phosphorus atoms enter the surface layer of the silicon wafer and permeate and diffuse into the silicon wafer through gaps among the silicon atoms to form an interface of the N-type semiconductor and the P-type semiconductor.

Because the diffusion junction forms a short circuit channel at the edge of the silicon wafer, photogenerated electrons collected by the front surface of the PN junction flow to the back surface of the PN junction along the region with phosphorus atoms diffused at the edge, and the short circuit is caused. And etching and removing the PN junction at the edge through plasma etching, thereby avoiding short circuit at the edge. Because the diffusion junction making process can form a layer of phosphorosilicate glass on the surface of the silicon wafer, the influence on the efficiency of the laminated cell is reduced through the phosphorosilicate glass removing process. And etching the silicon wafer without the phosphorosilicate glass, and then producing a silicon dioxide layer on the front and back surfaces of the cell through an oxygen high-temperature furnace at a certain temperature. And then laminating an aluminum oxide passivation film layer in an ALD or PECVD mode. A silicon nitride film is laminated on the aluminum oxide film layer, the silicon nitride on the front surface plays a role in reducing reflection and passivating, and the silicon nitride film on the rear surface plays a role in protecting aluminum oxide. Laser grooving is carried out on the back of the coated silicon wafer, back and front printing is completed through screen printing, small front and back electrodes are required to be in staggered positions on the front and back surfaces after the printed pattern is cut, then a sintering process is carried out, photoinduced attenuation of a battery cell is reduced through a light attenuation furnace or an electric injection furnace, and finally battery testing is graded.

Adding an online laser cutting scribing process to the whole sintered laminated cell, entering the sintered laminated cell into a scribing detection position for appearance inspection and visually positioning an OK sheet (poor appearance detection can automatically shunt to an NG position), and freely setting a multi-track scribing machine or presetting a cache stack area according to an online production beat so as to realize online continuous feeding operation. And setting relevant parameters of the laser according to the optimal effect of cutting and scribing so as to realize higher cutting speed, narrower cutting heat affected zone and cutting line width, better uniformity, preset cutting depth and the like. After the automatic cutting is finished, the automatic sheet breaking mechanism of the online laser scribing machine is used for breaking sheets at the cutting position to realize natural separation of the small laminated tiles (the laser cutting surface is far away from the side of a PN junction to avoid leakage current caused by damage of the PN junction, the directions of the front surface and the back surface of the battery sheet are confirmed before the sheet is scribed and fed, and if the directions are opposite, a single 180-degree reversing device is required to be added); the dice are then subjected to an interconnect string.

The connection mode of the solar cell pieces and the bus bar in the invention is different from the traditional welding mode or the mode of utilizing adhesives such as conductive adhesive or tin paste, and the bus bar of the solar cell module in the invention is directly contacted with the conductive structure of each solar cell piece and is fixed with each solar cell piece through the non-conductive adhesives. The invention can avoid the defects of the conventional welding mode and the mode of utilizing the conductive adhesive, for example, the reliability risk of the assembly caused by the failure of the conductive adhesive/solder paste can be greatly reduced, and the defect of incomplete double functions of the adhesion and the conduction of the conductive adhesive is avoided. And moreover, the risk of glue overflow of the conductive adhesive can be avoided, the assembly cost is greatly reduced, and the possibility of cracking caused by welding stress is avoided. In addition, the bus bar is not provided with the tin layer, so that the cost can be further reduced.

The foregoing description of various embodiments of the invention is provided for the purpose of illustration to one of ordinary skill in the relevant art. It is not intended that the invention be limited to a single disclosed embodiment. As mentioned above, many alternatives and modifications of the present invention will be apparent to those skilled in the art of the above teachings. Thus, while some alternative embodiments are specifically described, other embodiments will be apparent to, or relatively easily developed by, those of ordinary skill in the art. The present invention is intended to embrace all such alternatives, modifications and variances of the present invention described herein, as well as other embodiments that fall within the spirit and scope of the present invention as described above.

Claims

1. A solar cell module, comprising:

2. The solar cell module as claimed in claim 1, wherein the non-conductive adhesive is applied at a position where the bus bar is in direct contact with the solar cell sheet at the end of each cell string.

3. The solar cell assembly of claim 1, wherein each solar cell segment includes grid lines disposed on a surface of the solar cell segment, the bus bars being in direct contact with the grid lines of the solar cell segment at the ends of each cell string.

4. The solar cell module of claim 3, wherein the grid lines of each solar cell segment comprise a plurality of minor grid lines and a major grid line in contact with each minor grid line, and the bus bar is in direct contact with the major or minor grid line of the solar cell segment at the end of each cell string.

5. The solar cell module as claimed in claim 1, wherein each solar cell sheet includes a grid line disposed on a surface of the solar cell sheet and a conductive connection portion connected to the grid line, and the bus bar is in direct contact with the conductive connection portion of the solar cell sheet at an end of each cell string.

6. The solar cell module of claim 5, wherein the grid lines of each solar cell slice comprise a plurality of minor grid lines and a major grid line in contact with each minor grid line, wherein:

7. The solar cell module according to claim 1, wherein the bottom surface of each solar cell sheet is provided with a back field, and the bus bar is in direct contact with a portion of the solar cell sheet at the end of each cell string where the back field is formed.

8. The solar cell module as claimed in claim 1, wherein the bottom surface of each solar cell is provided with a back field on which a plurality of conductive connections are provided, the bus bars being in direct contact with the conductive connections of the solar cells at the end of each cell string.

9. The solar cell module according to any one of claims 1 to 8, wherein the non-conductive adhesive is a dot structure made of acrylic resin, silicone resin, epoxy resin, or polyurethane.

10. The solar cell module as claimed in any one of claims 1 to 8, wherein the bus bar is a continuous strip structure made of tin-plated copper or copper foil.

11. The solar cell module as claimed in any one of claims 1 to 8, wherein the surface of the bus bar is free of a tin layer.

12. The solar cell module according to any one of claims 1 to 8,

in each cell string, all solar cells are arranged in a shingled mode, and adjacent solar cells are in conductive connection through direct contact of a conductive structure; or

13. A method of manufacturing a solar cell module, the method comprising the steps of:

14. The method of claim 13, wherein the step of applying a non-conductive adhesive comprises: a non-conductive adhesive is applied at a location where the bus bar is in direct contact with the solar cell sheet at the end of each cell string.

15. The method of claim 13,

the step of arranging a plurality of solar cells comprises the following steps: applying grid lines on the surface of a large cell piece forming a plurality of solar cell pieces;

16. The method of claim 15, wherein for each solar cell, the grid lines comprise a plurality of minor grid lines and a major grid line in contact with each minor grid line; the step of providing the bus bar includes: so that the bus bars are in direct contact with the sub-grid lines or the main grid lines of the solar cell pieces at the end of each cell string.

17. The method of claim 13,

the step of arranging a plurality of solar cells comprises the following steps: applying grid lines on the surface of a large cell piece forming a plurality of solar cell pieces; conductive connecting parts connected with the grid lines are applied on the surface of the large sheet of the battery piece,

18. The method of claim 13,

the step of arranging a plurality of solar cells comprises the following steps: arranging a back electric field on the bottom surface of a cell sheet of the plurality of solar cell sheets;

19. The method of claim 13,

the step of arranging a plurality of solar cells comprises the following steps: arranging a back electric field on the bottom surface of a large cell piece forming a plurality of solar cell pieces, and arranging a conductive connecting part on the back electric field;

20. Method according to any of claims 13-19, characterized in that acrylic, silicone, epoxy or polyurethane is chosen as the non-conductive adhesive.

21. The method of claim 20, wherein a curing agent, a cross-linking agent, a coupling agent, or rubber balls are added to the material from which the non-conductive adhesive is made.

22. The method according to any one of claims 13-19, wherein the bus bar is made of tin-plated copper or copper foil.

23. Method according to any of claims 13-19, characterized in that the method does not comprise the step of providing a tin layer on the surface of the bus bar.

24. The method according to any one of claims 13 to 19,

the step of setting each battery string includes: arranging all solar cells in a shingled manner, and realizing conductive connection between adjacent solar cells through direct contact of a conductive structure; or