阅读说明：本技术 导电背板及生产方法、光伏组件及制备方法 (Conductive back plate and production method thereof, photovoltaic module and preparation method thereof ) 是由 李华 刘继宇 于 2020-06-08 设计创作，主要内容包括：本发明提供导电背板及生产方法、光伏组件及制备方法,涉及光伏技术领域。导电背板包括：连接层和背膜层,以及位于两者之间的导电层；连接层包括：基体部分和凸出基体部分的凸起部分；连接层具有电连接太阳能电池的背面电极与导电线路的导电区、和阻断相邻导电区的绝缘区；导电区和绝缘区均贯穿连接层；导电粒子位于导电区内。进而,太阳能电池倾斜设置在连接层中基体部分和凸起部分形成的空间内,凸起部分的凸起面和太阳能电池的背光面相对,连接层中凸起部分的绝缘基膜在层压过程中熔化、并流动至相邻太阳能电池之间,形成粘接介质,无需在太阳能电池之间施加连接材料,工艺简单,隐裂少。(The invention provides a conductive back plate, a production method, a photovoltaic module and a preparation method, and relates to the technical field of photovoltaics. The conductive backsheet includes: the connecting layer and the back film layer, and the conducting layer between the connecting layer and the back film layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connecting layer is provided with a conductive region for electrically connecting the back electrode of the solar cell and the conductive circuit and an insulating region for blocking the adjacent conductive region; the conductive region and the insulating region both penetrate through the connecting layer; the conductive particles are located within the conductive region. Furthermore, the solar cells are obliquely arranged in the space formed by the base body part and the protruding part in the connecting layer, the protruding surface of the protruding part is opposite to the backlight surface of the solar cells, the insulating base film of the protruding part in the connecting layer is melted in the laminating process and flows between the adjacent solar cells to form an adhesive medium, connecting materials do not need to be applied between the solar cells, the process is simple, and hidden cracks are few.)

1. A conductive backsheet, comprising: the back film layer is arranged on the back film layer and is provided with a connecting layer; the conductive layer is provided with a conductive circuit;

the connection layer includes: a base portion and a projection portion projecting from the base portion;

the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located within the conductive region.

2. The conductive backsheet of claim 1, wherein the raised portions are periodically distributed in the connecting layer.

3. The conductive backsheet according to claim 1 or 2, wherein a distance between centers of two adjacent convex portions is equal to or less than a length of one solar cell in a direction parallel to the backsheet layer.

4. The conductive backsheet according to claim 1 or 2, wherein the height of the protrusion portion protruding from the base portion is 20-200 um.

5. The conductive backsheet according to claim 1 or 2, wherein a cross-sectional shape of the convex portion in an arrangement direction of the connection layer and the backsheet layer includes: triangular, rectangular, circular arc and wave.

6. The conductive backplane according to claim 1 or 2, wherein the width of each of the conductive areas is less than or equal to the width of the back electrode to be electrically connected.

7. The conductive backsheet according to claim 1 or 2, wherein the material of the conductive particles is selected from the group consisting of: silver particles, copper particles, aluminum particles, indium alloy particles, tin alloy particles, silver-coated copper particles, graphene oxide particles, poly (3, 4-ethylenedioxythiophene): at least one of poly (styrene sulfonate) particles, particles of silver coated thermoplastic polymer;

the shape of the conductive particles is at least one of spherical, spheroidal and irregular;

the average particle diameter of the conductive particles is 0.1-100 um.

8. The conductive backsheet according to claim 1 or 2, wherein the connection layer has a series resistivity in a vertical direction of less than 1 Ω -cm with the conductive layer after heating and/or pressure²。

9. The conductive backsheet according to claim 1 or 2, wherein the material of the insulating base film is selected from: at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral, or silicone gel.

10. The conductive backsheet according to claim 1 or 2, wherein the conductive layer is a patterned metal foil or a plurality of conductive wires disposed on an adhesive film.

11. A method for producing a conductive backboard is characterized by comprising the following steps:

providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are positioned in the conductive region;

providing a back film layer and a conductive layer; the conductive layer is provided with a conductive circuit;

and sequentially laminating the connecting layer, the conductive layer and the back film layer, and performing hot-press fitting.

12. The method for producing a conductive backsheet according to claim 11, wherein the step of providing a connection layer comprises:

and the insulating base film precursor particles and the mixture of the insulating base film precursor particles and the conductive particles are extruded, cast and cooled to form the connecting layer.

13. The method for producing a conductive backsheet according to claim 11, wherein the hot pressing temperature is 60 to 120 ℃, the pressure is 0.01 to 0.2MPa, and the hot pressing time is 1 to 30 min.

14. The method for producing a conductive backsheet according to claim 11, wherein the base portion and the convex portion are integrally formed.

15. A photovoltaic module comprising a plurality of solar cells having a back electrode, conductive regions in the conductive backsheet of any one of claims 1 to 10 electrically connecting the back electrode of the solar cells and the conductive traces of the conductive backsheet;

in the packaging process of forming the assembly, the solar cell is obliquely arranged in an inner concave space formed by the base part and the convex part in the connecting layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell;

an adhesive medium is arranged between the adjacent solar cells, and the adhesive medium is formed by melting and flowing the insulating base film of the convex part in the connecting layer in the laminating process.

16. The photovoltaic module of claim 15, wherein the front encapsulant film on the light-facing side of the solar cell comprises: a base film portion and a projecting portion projecting from the base film portion;

the base part and the convex part in the connecting layer, and the base film part and the convex part in the front packaging adhesive film form an inner concave space together, and the solar cell is obliquely arranged in the inner concave space;

in the photovoltaic module, the convex parts in the connecting layer and the convex parts in the front packaging adhesive film which are positioned at two sides of the same solar cell are distributed in a staggered mode, and the convex surfaces of the convex parts of the front packaging adhesive film are opposite to the light facing surfaces of the solar cell.

17. The photovoltaic module of claim 16, wherein the protruding portions are periodically distributed in the front encapsulant film.

18. A preparation method of a photovoltaic module is characterized by comprising the following steps:

providing a conductive backsheet as claimed in any one of claims 1 to 10;

providing a solar cell having a back electrode;

obliquely laying a solar cell in an inner concave space formed by a base body part and a convex part in a connecting layer to obtain a component precursor, so that a back electrode of the solar cell is opposite to a conductive region in the connecting layer, and a convex surface of the convex part is opposite to a backlight surface of the solar cell;

laminating the stack including the assembly precursor so that the back electrode of the solar cell is electrically connected to the conductive region in the conductive backsheet, and the insulating base film of the convex portion in the connection layer is melted during the lamination process and flows between adjacent solar cells to form an adhesive medium.

19. A preparation method of a photovoltaic module is characterized by comprising the following steps:

providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are positioned in the conductive region;

providing a back film layer;

providing a conductive layer;

providing a solar cell having a back electrode;

stacking the connecting layer, the conductive layer and the back film layer in sequence, and laying a solar cell in an inclined manner in an inner concave space formed by a base body part and a convex part in the connecting layer to obtain a module precursor, so that a back electrode of the solar cell is arranged opposite to the conductive region in the connecting layer, and the convex surface of the convex part is opposite to the back surface of the solar cell;

laminating the stack including the assembly precursor so that the back electrode of the solar cell is electrically connected to the conductive region in the conductive backsheet, and the insulating base film of the convex portion in the connection layer is melted during the lamination process and flows between adjacent solar cells to form an adhesive medium.

20. The method of claim 18 or 19, wherein the laminating process comprises a second heat press application.

Technical Field

The invention relates to the technical field of photovoltaics, in particular to a conductive back plate and a production method thereof, a photovoltaic module and a preparation method thereof.

Background

The back contact solar cell has the advantages that the light facing surface is not provided with the main grid line, so that shading is reduced, the short circuit current of the cell is increased, and meanwhile, the back contact solar cell is more attractive, so that the back contact solar cell is widely applied.

Aiming at the battery assembly, the gaps among the batteries in the assembly are reduced, the power output of the battery assembly can be improved, and the appearance is more attractive.

However, for the back contact solar cell, the main grid lines are all arranged on the backlight surface, and the process for reducing the gaps among the cells in the cell module is complex.

Disclosure of Invention

The invention provides a conductive back plate and a production method thereof, a photovoltaic module and a preparation method thereof, and aims to solve the problem that the process for reducing gaps among cells in the conventional back contact solar cell is complex.

According to a first aspect of the present invention, there is provided a conductive backsheet comprising: the back film layer is arranged on the back film layer and is provided with a connecting layer; the conductive layer is provided with a conductive circuit;

the connection layer includes: a base portion and a projection portion projecting from the base portion;

the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located within the conductive region.

The conductive area in the connecting layer of the conductive backboard is used for electrically connecting the back electrode of the solar cell and the conductive circuit of the conductive layer in the conductive backboard, the insulating effect is realized through the insulating area in the connecting layer of the conductive backboard, and the short circuit between the positive electrode and the negative electrode can be avoided. The insulating base film of the convex part in the connecting layer is melted and flows between the adjacent solar cells in the subsequent laminating process to form a bonding medium so as to bond each solar cell, and then a connecting material is not required to be additionally applied between each solar cell, so that the process steps are reduced, the process is simple, and the production efficiency is improved. And the melted insulating base film is filled in gaps between adjacent solar cells or in the assembly, so that the pressure born by the solar cells in the laminating process can be reduced, the hidden crack can be reduced, and the production yield can be improved. Meanwhile, the solar cell is obliquely arranged in the concave space formed by the base body part and the convex part in the connecting layer, and the concave space can reduce the pressure born by the solar cell in the laminating process, reduce the hidden crack and improve the production yield. And the inclined arrangement is favorable for reducing gaps among the solar cells so as to improve the power output of the cell module. Meanwhile, the concave space formed by the base body part and the convex part in the connecting layer has a certain positioning function, so that the laying and alignment of the solar cell are facilitated, and the production efficiency is improved.

According to a second aspect of the present invention, there is provided a method for producing a conductive backsheet, comprising the steps of:

providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are positioned in the conductive region;

providing a back film layer and a conductive layer; the conductive layer is provided with a conductive circuit;

and sequentially laminating the connecting layer, the conductive layer and the back film layer, and performing hot-press fitting.

According to a third aspect of the present invention, there is provided a photovoltaic module comprising a plurality of solar cells having a back electrode, electrically connecting the back electrode of the solar cells and the conductive tracks of the conductive backsheet using conductive regions in the conductive backsheet as described in any of the preceding paragraphs;

in the packaging process of forming the assembly, the solar cell is obliquely arranged in an inner concave space formed by the base part and the convex part in the connecting layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell;

an adhesive medium is arranged between the adjacent solar cells, and the adhesive medium is formed by melting and flowing the insulating base film of the convex part in the connecting layer in the laminating process.

According to a fourth aspect of the present invention, there is provided a photovoltaic module manufacturing method, comprising the steps of:

providing a conductive backsheet as described in any of the preceding;

providing a solar cell having a back electrode;

obliquely laying a solar cell in an inner concave space formed by a base body part and a convex part in a connecting layer to obtain a component precursor, so that a back electrode of the solar cell is opposite to a conductive region in the connecting layer, and a convex surface of the convex part is opposite to a backlight surface of the solar cell;

laminating the stack including the assembly precursor so that the back electrode of the solar cell is electrically connected to the conductive region in the conductive backsheet, and the insulating base film of the convex portion in the connection layer is melted during the lamination process and flows between adjacent solar cells to form an adhesive medium.

The conductive back plate production method, the photovoltaic module and the photovoltaic module preparation method have the same or similar beneficial effects as the conductive back plate, and are not repeated herein for avoiding repetition.

According to a fifth aspect of the present invention, there is provided a photovoltaic module manufacturing method, comprising the steps of:

providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are positioned in the conductive region;

providing a back film layer;

providing a conductive layer;

providing a solar cell having a back electrode;

stacking the connecting layer, the conductive layer and the back film layer in sequence, and laying a solar cell in an inclined manner in an inner concave space formed by a base body part and a convex part in the connecting layer to obtain a module precursor, so that a back electrode of the solar cell is arranged opposite to the conductive region in the connecting layer, and the convex surface of the convex part is opposite to the back surface of the solar cell;

laminating the stack including the assembly precursor so that the back electrode of the solar cell is electrically connected to the conductive region in the conductive backsheet, and the insulating base film of the convex portion in the connection layer is melted during the lamination process and flows between adjacent solar cells to form an adhesive medium.

The preparation method of the photovoltaic module achieves the same or similar beneficial effects of the conductive backboard, meanwhile, the connecting layer, the conductive layer and the back membrane layer which form the conductive backboard are not specially subjected to hot pressing and laminating, and hot pressing and laminating of the connecting layer, the conductive layer and the back membrane layer are completed by means of laminating in the process of forming the photovoltaic module, so that hot pressing steps are reduced, production efficiency is improved, energy consumption is reduced, and production cost is reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a first conductive backplane according to an embodiment of the present invention;

FIG. 2 shows a schematic structural view of a first photovoltaic stack in an embodiment of the present invention;

FIG. 3 shows a schematic diagram of a conductive layer in an embodiment of the invention;

FIG. 4 shows a schematic structural diagram of another conductive layer in an embodiment of the invention;

FIG. 5 shows a schematic structural diagram of yet another conductive layer in an embodiment of the invention;

FIG. 6 is a schematic structural diagram of a second conductive backplane according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a third conductive backsheet in an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a fourth conductive backsheet in an embodiment of the present invention;

FIG. 9 shows a schematic structural diagram of a solar cell in an embodiment of the invention;

fig. 10 shows a schematic structural view of another solar cell in an embodiment of the invention;

fig. 11 is a schematic view showing a partial structure of an insulation base film extrusion apparatus according to an embodiment of the present invention;

fig. 12 is a schematic view showing a partial structure of another insulation base film extrusion apparatus according to an embodiment of the present invention;

figure 13 shows a schematic structural view of a second photovoltaic stack in an embodiment of the present invention;

figure 14 shows a schematic structural view of a third photovoltaic stack in an embodiment of the present invention.

Description of the figure numbering:

1-a back film layer, 2-a conductive layer, 3-a connection layer, 4-a solar cell, 311-a conductive region, 312-an insulating region, 21-an adhesive film, 22-a conductive line, 23-a metal foil, 24-an isolation region, 25-a bonding site, 41-a first main gate line, 42-a second main gate line, 43-a first sub gate line, 44-a second sub gate line, 51-a first region of an insulating base film extrusion device, 52-a second region of the insulating base film extrusion device, and 5-a front encapsulation adhesive film.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the embodiment of the present invention, referring to fig. 1, fig. 1 shows a schematic structural diagram of a first conductive backplane in the embodiment of the present invention. The conductive backsheet includes: a connecting layer 3 and a backing film layer 1, and a conductive layer 2 positioned between the connecting layer 3 and the backing film layer 1. The conductive layer 2 has conductive lines.

The backing layer 1 may be only an encapsulation adhesive film, or the backing layer 1 may be a combination of an encapsulation adhesive film and a backing layer. In the embodiment of the present invention, this is not particularly limited.

The connection layer includes: a base portion and a projection portion projecting from the base portion. Referring to fig. 1, the flat region of the connection layer 3 may be a base portion, and a convex portion may protrude from the base portion. The composition of the raised portion may be the same as or different from the composition of the base portion. The projection portion and the base portion may be integrally formed or may be formed in steps. In the embodiment of the present invention, this is not particularly limited.

The connection layer 3 has conductive regions 311 for electrically connecting the back electrodes of the solar cells and the conductive lines, and insulating regions 312 blocking the adjacent conductive regions 311. Both the conductive region 311 and the insulating region 312 penetrate the connection layer 3, i.e., the conductive region and the insulating region at the base portion penetrate the base portion, and the conductive region and the insulating region at the convex portion penetrate the convex portion. The widths of the conductive regions 311 may be equal or different, and the widths of the insulating regions 312 may be equal or different, which is not particularly limited in the embodiment of the present invention. Referring to fig. 1, the conductive regions 311 and the insulating regions 312 at the base portion have a height equal to that of the base portion. The conductive regions 311 and the insulating regions 312 located at the bumpy portions have a height equal to that of the corresponding bumpy portions. The connection layer includes an insulating base film and conductive particles dispersed in the insulating base film, i.e., the base portion and the convex portion each include an insulating base film and conductive particles dispersed in the insulating base film. Conductive particles are located in the conductive region 311. That is, the conductive region 311 is composed of an insulating base film and conductive particles dispersed in the insulating base film. The insulating region 312 is composed of an insulating base film. The number of conductive particles included in each conductive region 311 is not particularly limited, so that the region can be flexibly set for the purpose of conduction. The sizes of the respective conductive regions 311 may be the same.

The solar cell may be a back contact solar cell, and a plurality of back electrodes are disposed in parallel on a back surface of the solar cell. The back electrode may be a bus bar. Referring to fig. 2, fig. 2 shows a schematic structural view of a first photovoltaic stack according to an embodiment of the present invention. The photovoltaic laminate is laminated to form a photovoltaic module. The conductive region 311 in the connecting layer 3 is used for electrically connecting the back electrode of the solar cell 4 and the conductive circuit of the conductive layer 2 in the conductive back plate, the conductive region 311 in the connecting layer 3 in the conductive back plate realizes the electrical connection between the conductive circuits of the solar cell 4 and the conductive layer 2, the insulating effect is realized through the insulating region in the connecting layer 3 of the conductive back plate, that is, only one layer of the connecting layer 3 in the conductive back plate realizes the electrical connection and the insulation at the same time, and the process is simple. Meanwhile, no hole is formed, the integrity of the connecting layer 3 cannot be damaged, and the conductive backboard is high in stability and reliability. The conductive region 311 in the connection layer 3 of the conductive backplane electrically connects the back electrode of the solar cell 4 and the conductive circuit of the conductive layer 2 in the conductive backplane, and the insulating effect is achieved through the insulating region in the connection layer 3 of the conductive backplane, so that short circuit between the positive electrode and the negative electrode can be avoided. The insulating base film of the convex part in the connecting layer 3 is melted in the subsequent laminating process and flows between the adjacent solar cells 4 to form a bonding medium so as to bond each solar cell 4, and further, a connecting material is not required to be additionally applied between each solar cell 4, so that the process steps are reduced, the process is simple, and the production efficiency is improved. Meanwhile, the solar cells are usually arranged in an overlapped mode, the light facing surface of one solar cell is overlapped with the backlight surface of the other solar cell, and the light facing surfaces of the solar cells are not provided with electrodes, so that even if a small amount of conductive particles on the convex parts move to the space between the adjacent solar cells due to melting of the insulating base film, short circuit or electric leakage cannot be caused. And the melted insulating base film is filled in the gaps between the adjacent solar cells 4 or in the assembly, so that the pressure born by the solar cells 4 in the laminating process can be reduced, the hidden cracks can be reduced, and the production yield can be improved.

Referring to fig. 2, the solar cell 4 is obliquely disposed in the concave space formed by the base portion and the convex portion in the connection layer 3, the convex surface of the convex portion is opposite to the backlight surface of the solar cell 4, and the oblique angle is specifically determined according to the height of the convex portion, the length of the solar cell, and the like, which is not specifically limited in the embodiment of the present invention. The inclined arrangement is beneficial to reducing the gaps among the solar cells 4 so as to improve the power output of the cell module. Meanwhile, the solar cell 4 is obliquely arranged in an inwards concave space formed by the base body part and the convex part in the connecting layer 3, the inwards concave space can reduce the pressure born by the solar cell in the laminating process, so that the hidden crack can be reduced, and the production yield is improved. Meanwhile, the concave space formed by the base body part and the convex part in the connecting layer 3 has a certain positioning function, the solar cells 4 can be conveniently laid and aligned by forward laying or reverse laying, and the production efficiency is improved.

Alternatively, the convex portions are periodically distributed in the connection layer, and the process is simple, for example, referring to fig. 1, the convex portions are periodically distributed on the connection layer 3.

Alternatively, referring to fig. 3, fig. 3 is a schematic structural diagram of a conductive layer in an embodiment of the present invention. The conductive layer shown in fig. 3 is a plurality of conductive lines 22 disposed on the adhesive film 21. The conductive wire 22 may be a circular solder strip or a flat solder strip commonly used in the industry, and the conductive wire 22 may further include an intermediate layer and a coating layer coated on the intermediate layer. The material of the intermediate layer may include at least one of copper, gold, silver, and aluminum. The coating may be a tin-containing solder.

Referring to fig. 4, fig. 4 is a schematic structural diagram of another conductive layer in the embodiment of the present invention. The conductive layer shown in fig. 4 is a patterned metal foil. In fig. 4, 23 is a metal foil, and 24 is a patterned isolation region. The width of the isolation region 24 is not particularly limited. The pattern may be formed by mechanical die cutting, laser die cutting or chemical etching. The pattern depends on the pattern of the solar cell backlight surface electrode, which may include a variety of shapes and/or sizes. The metal foil may be made of copper or aluminum foil or any other suitable metal or metal alloy. The thickness of the metal foil may provide a current path with low resistance. If the metal foil is selected from copper foil or aluminum foil, the thickness may be 20-100um, or 30-60 um.

Referring to fig. 5, fig. 5 is a schematic structural diagram of another conductive layer in the embodiment of the present invention. The conductive layer shown in fig. 5 is a patterned metal foil. In fig. 5, bonding sites 25 are further provided in the metal foil 23 in one-to-one correspondence with the respective conductive areas in the connection layer to facilitate accurate alignment of the connection layer with the conductive layer.

Alternatively, as shown in fig. 2, in a direction parallel to the back film layer 1, a distance between centers of two adjacent convex portions is less than or equal to a length of one solar cell 4, thereby facilitating the inclined placement of the solar cell 4.

Alternatively, as shown in fig. 1, the height d of the protruding portion protruding the base portion is 20-200um, and the insulating base film of the protruding portion in the thickness range flows after being melted in the subsequent lamination or heating process, so as to form a bonding medium fully filling between the adjacent solar cells 4, so as to bond the solar cells 4. And the melted insulating base film can be fully filled in gaps between adjacent solar cells 4 or in the assembly, so that the inclination angle of the solar cells 4 in the laminating process can be reduced, and the gaps among the solar cells 4 can be reduced, thereby improving the power output of the battery assembly. The hidden crack can be further reduced, and the production yield can be improved.

Optionally, in the setting direction of the connection layer and the back film layer, the cross-sectional shape of the convex portion includes: triangular, rectangular, circular arc and wave. And the form of the convex portion is various. For example, referring to fig. 1, the cross-section of the convex portion is triangular in shape. Referring to fig. 6, fig. 6 is a schematic structural diagram of a second conductive backplane according to an embodiment of the present invention. Referring to fig. 6, the cross-section of the convex portion is rectangular.

Optionally, the width of the conductive region is less than or equal to the width of the back electrode to be electrically connected, so that even if the conductive region has a certain deformation amount in a heating or hot-pressing process, a short circuit cannot be caused, and the insulating effect is good.

Optionally, the number of the conductive regions in each of the protruding portions is greater than or equal to 1, and a solar cell may be obliquely laid in the concave space corresponding to the base portion and the protruding portion in each of the protruding portions. For example, referring to the conductive backplane shown in fig. 1, the number of conductive regions 311 in each of the bumpy portions is 3. As another example, as shown in fig. 6, the number of the conductive regions 311 in each convex portion is 2. For another example, fig. 7 shows a schematic structural diagram of a third conductive backplane according to an embodiment of the present invention. In fig. 7, the cross-sectional shape of the convex portion is triangular in the direction in which the tie layer 3 and the backing film layer 1 are disposed. Referring to the conductive backplane shown in fig. 7, the number of the conductive regions 311 in each bump portion is 1, and the number of the conductive regions 311 in the base portion between the adjacent bump portions is 1. For another example, fig. 8 shows a schematic structural diagram of a fourth conductive backplane in an embodiment of the present invention. In fig. 8, the cross-sectional shape of the convex portion is rectangular in the direction in which the tie layer 3 and the backing film layer 1 are provided. In the conductive backsheet shown in fig. 8, the number of the conductive regions 311 in each bump portion is 1, and the number of the conductive regions 311 in the base portion between the adjacent bump portions is 1.

In the case where the number of the conductive regions in the bump portion is equal to 1, the width of each conductive region is less than or equal to half the width of the bump portion, and further, the bump portion may be further provided with an insulating region, so that short circuit can be avoided. It should be noted that if the number of the conductive regions in the protruding portion is equal to 1, the back electrode of the solar cell electrically connected thereto may be as shown in fig. 9, and fig. 9 shows a schematic structural diagram of a solar cell in an embodiment of the present invention. Fig. 9 may be a bottom view looking from the backlight surface of the solar cell toward the light-facing surface. The first and second bus bars 41 and 42 in fig. 9 are respectively disposed at both ends of the battery, wherein the first and second bus bars 41 and 42 have opposite polarities. The first sub gate line 43 is connected to the first main gate line 41, and the second sub gate line 44 is connected to the second main gate line 42. For example, if the first main gate line 41 is an anode main gate line, the second main gate line 42 is a cathode main gate line, the first sub gate line 43 is an anode sub gate line, and the second sub gate line 44 is a cathode sub gate line. The positive and negative bus bars are disposed at both ends of the battery, respectively, so that 1 conductive region 311 provided in each raised portion in the conductive back sheet shown in fig. 7 or 8 and 1 conductive region 311 of the adjacent base portion can be conductively connected to the corresponding bus bar. Two conductive regions 311 located in adjacent 2 raised portions are used to connect the positive bus bar of one of the adjacent two cells to the negative bus bar of the other cell.

If the number of the conductive regions in the convex portion is greater than 1, the back electrode of the solar cell to which the conductive regions are electrically connected may be as shown in fig. 10, and fig. 10 shows a schematic structural view of another solar cell in the embodiment of the present invention. Fig. 10 may be a bottom view looking from the backlight surface of the solar cell toward the light-facing surface. The first and second main gate lines 41 and 42 in fig. 10 are arranged in parallel and alternately, wherein the first and second main gate lines 41 and 42 have opposite polarities. The first sub gate line 43 is connected to the first main gate line 41, and the second sub gate line 44 is connected to the second main gate line 42. For example, if the first main gate line 41 is an anode main gate line, the second main gate line 42 is a cathode main gate line, the first sub gate line 43 is an anode sub gate line, and the second sub gate line 44 is a cathode sub gate line. The solar cell shown in fig. 10 may be conductively connected to a corresponding bus bar using the conductive region 311 in each of the bumpy portions and the conductive region 311 of the adjacent base portion in the conductive backsheet shown in fig. 1 or 6.

Optionally, the conductive particles have deformability in the heating and/or pressing process, on one hand, the conductive particles are not crushed in the heating and/or pressing process, and the conductive effect among the back electrode, the conductive region and the conductive layer is not affected, and on the other hand, the transverse area of each conductive particle in the conductive region is increased in the pressing and/or heating process, the contact area with the back electrode and the conductive layer is increased, and the enhancement of the conductive effect in the vertical direction is facilitated.

Optionally, the shape of the conductive region is a continuous strip shape or a discontinuous point shape, and the conductive region in the shape enables a good conductive effect among the back electrode, the conductive region and the conductive layer of the solar cell.

Optionally, after being heated and/or pressed, the series resistivity of the connection layer and the conductive layer in the vertical direction is less than or equal to 1 Ω · cm². Furthermore, after being heated and/or pressed, the back electrode, the conductive area and the conductive layer of the solar cell have good conductive effect.

Optionally, the material of the conductive particles is selected from: silver particles, copper particles, aluminum particles, indium alloy particles, tin alloy particles, silver-coated copper particles, graphene oxide particles, poly (3, 4-ethylenedioxythiophene): at least one of poly (styrene sulfonate) particles, particles of silver coated thermoplastic polymer. The conductive particles of the material have good deformability in the heating and/or pressing process and good conductivity. The particles of thermoplastic polymer may be PMMA (polymethyl methacrylate). The poly (3, 4-ethylenedioxythiophene): the poly (styrene sulfonate) particles may be/PEDOT: PSS gel.

Optionally, the conductive particles are at least one of spherical, spheroidal and irregular, and the conductive particles with the shapes have good conductive effect.

Optionally, the average particle size of the conductive particles is 0.1-100um, since the conductive particles are only distributed in the corresponding region where the connection layer is connected with the back electrode of the solar cell, the conductive particles have conductivity only in the direction where the back electrode of the cell is opposite to the conductive layer of the conductive backsheet in the vertical direction after lamination, and due to the blocking effect of the insulating region in the connection layer between adjacent electrodes in the horizontal direction, even though the deformation of the conductive particles in the conductive region may be enlarged, the conductive particles in the adjacent opposite electrical region cannot be directly contacted due to the size limitation of the conductive particles, and the defects such as short circuit and the like are not generated, and the conductive particles of the above size have a good conductive effect.

It can be understood that: the thickness of the connection layer needs to be larger than the particle diameter of the conductive particles, and the thickness of the connection layer and the average particle diameter of the conductive particles need to be set in cooperation with each other.

Alternatively, the insulating region in the connection layer may be a base insulating film, and the base insulating film in the conductive region and the base insulating film in the insulating region in the connection layer are made of materials selected from: the insulation base film comprises at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (POE), polyvinyl butyral (PVB) or silica gel, and the insulation base film has good insulation performance. The material of the insulating base film in the insulating region may be the same as or different from that of the conductive region, and this is not particularly limited in the embodiment of the present invention.

The back film layer may be an encapsulating adhesive film layer or a combination of an encapsulating adhesive film layer and a back plate layer. The encapsulating adhesive film layer may be composed of a resin including one or more of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (POE), polyvinyl butyral (PVB), or silica gel. The polymeric backsheet may use TPT, TPE, KPE, KPK, KPC or KPF. Alternatively, the polymer back sheet may include a polymer multilayer structure in which several layers of an insulating material (e.g., PET or PP) and an adhesive layer are compounded, the thickness and cost may be greatly reduced, and excellent electrical insulation and weather resistance may be secured. The embodiment of the present invention is not particularly limited thereto.

The application also provides a production method of the conductive backboard, which specifically comprises the following steps:

step S1, providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located within the conductive region.

Step S2, providing a back film layer and a conductive layer; the conductive layer has a conductive line.

And step S3, sequentially laminating the connecting layer, the conducting layer and the back film layer, and performing hot-press fitting.

It should be noted that the thermal pressing in step S3 may be the result of the lamination process of forming the photovoltaic module, or a special thermal pressing before forming the photovoltaic module, or a combination of the thermal pressing before forming the photovoltaic module and the secondary thermal pressing of the lamination process of forming the photovoltaic module. In the embodiment of the present invention, this is not particularly limited.

For example, the connection layer, the conductive layer, and the back film layer are sequentially stacked and preliminarily heated, so that the conductive particles in one conductive region in the connection layer are preliminarily deformed and locally contacted with the adjacent conductive particles in the conductive region, and the local contact does not ensure good electrical connection. And subsequently, the prepared conductive back plate, the solar cell, the packaging adhesive film and the cover plate are stacked and then sent into a laminating machine to be laminated to prepare the photovoltaic module. The laminating machine can perform secondary hot-pressing lamination, so that the conductive particles in one conductive area in the connecting layer can be further deformed to increase the contact between the adjacent conductive particles in the conductive area and the adjacent surface, and a good current path is formed.

Optionally, in step S3, the hot pressing temperature is 60-120 ℃, the pressure is 0.01-0.2MPa, and the hot pressing time is 1-30 min.

Optionally, the step S1 of providing the connection layer includes: and the insulating base film precursor particles and the mixture of the insulating base film precursor particles and the conductive particles are extruded, cast and cooled to form the connecting layer.

Specifically, referring to fig. 11, fig. 11 is a schematic view illustrating a partial structure of an insulation base film extrusion apparatus according to an embodiment of the present invention. The insulation base film extrusion apparatus may be divided into a first zone 51 and a second zone 52. The first regions 51 and the second regions 52 are alternately arranged. The first region 51 is filled with particles of the insulating base film precursor, and the particles of the insulating base film precursor in the first region 51 are extruded, cast, and cooled to form an insulating region of the connection layer. The insulating base film precursor pellets in the second region 52 are filled with the insulating base film precursor pellets in the second region 52 to which conductive particles are added, and the insulating base film precursor pellets to which conductive particles are added in the second region 52 are extruded, tape-cast, and cooled to form a conductive region of the connection layer. It should be noted that the first zone 51 and the second zone 52 can be extruded, cast, and cooled simultaneously to form the connecting layer. The shape of the convex portion in the connection layer obtained by the insulating base film extrusion apparatus shown in fig. 11 may be triangular.

Referring to fig. 12, fig. 12 is a partial schematic view showing another insulation base film extrusion apparatus according to an embodiment of the present invention. The insulation base film extrusion apparatus may also be divided into a first zone 51 and a second zone 52. The first regions 51 and the second regions 52 are alternately arranged. The first region 51 is filled with particles of the insulating base film precursor, and the particles of the insulating base film precursor in the first region 51 are extruded, cast, and cooled to form an insulating region of the connection layer. The insulating base film precursor pellets in the second region 52 are filled with the insulating base film precursor pellets in the second region 52 to which conductive particles are added, and the insulating base film precursor pellets to which conductive particles are added in the second region 52 are extruded, tape-cast, and cooled to form a conductive region of the connection layer. It should be noted that the first zone 51 and the second zone 52 can be extruded, cast, and cooled simultaneously to form the connecting layer. The shape of the convex portion in the connection layer obtained by the insulating base film extrusion apparatus shown in fig. 12 may be rectangular.

The particles of the insulating base film precursor may further include: at least one of curing agent, inorganic filler, cross-linking agent, initiator and coupling agent. The curing agent may include at least one of a silane terminated thiol, dicumyl peroxide, dicumyl hydroperoxide, or benzoyl peroxide. The inorganic filler may be at least one of titanium dioxide, barium sulfate, calcium carbonate or carbon black. The initiator may be at least one of dicumyl peroxide, dicumyl hydroperoxide or benzoyl peroxide. The coupling agent is a silane coupling agent or a titanate coupling agent.

Optionally, in the connection layer, the base portion and the protruding portion are integrally formed, so that the production efficiency can be improved. Alternatively, in the connection layer, the base portion and the convex portion are formed separately, which is not particularly limited in the embodiment of the present invention.

Embodiments of the present invention also provide a photovoltaic module, such as the photovoltaic laminate shown in fig. 2, which is laminated to form a photovoltaic module. The photovoltaic module comprises a plurality of solar cells 4, wherein each solar cell 4 is provided with a back electrode, a conductive area 311 in any one of the conductive back plates is adopted, and the conductive circuit is electrically connected with the back electrode of each solar cell 4 and the conductive layer 2 of the conductive back plate. In the packaging process of forming the module, the solar cell 4 is obliquely arranged in the concave space formed by the base part and the convex part in the connecting layer, and the convex surface of the convex part of the connecting layer is opposite to the backlight surface of the solar cell 4. Between adjacent solar cells 4, there is an adhesive medium formed by melting and flowing the insulating base film of the convex portion in the connection layer during the lamination process.

For another example, referring to fig. 13, fig. 13 shows a schematic structural view of a second photovoltaic stack in an embodiment of the present disclosure. The photovoltaic laminate is laminated to form a photovoltaic module. For another example, referring to fig. 14, fig. 14 shows a schematic structural view of a third photovoltaic stack in an embodiment of the present invention. The photovoltaic stack shown in fig. 14 may have a larger area of overlap of the individual solar cells in the photovoltaic module after lamination. The photovoltaic laminate is laminated to form a photovoltaic module. For the photovoltaic laminate and the laminated photovoltaic module, reference may be made to the above description, and details thereof are not repeated herein in order to avoid redundancy.

Each part of the photovoltaic module refers to the related description, and similar beneficial effects can be achieved, and details are not repeated herein to avoid repetition.

Optionally, as shown in fig. 2, 13, and 14, the front encapsulant film 5 on the light-facing surface of the solar cell 4 includes: a base film portion and a projecting portion projecting from the base film portion. The height of the protruding portion protruding out of the base film portion can be set according to actual needs, and is not particularly limited in the embodiment of the present invention. In photovoltaic module, the base part and the bulge of solar cell connecting layer slope setting in the connecting layer to and preceding encapsulation glued membrane in base film part and the bulge, in the common indent space that forms, the indent space that both formed is bigger, and the slope of the solar cell of being convenient for is placed.

In the photovoltaic module, the convex parts in the connecting layers positioned on two sides of the same solar cell and the convex parts in the front packaging adhesive film are distributed in a staggered mode, the convex surfaces of the convex parts of the front packaging adhesive film are opposite to the light facing surfaces of the solar cells 4, so that the solar cells can be placed in an inclined mode conveniently, and the convex parts in the connecting layers are not opposite to the convex parts in the front packaging adhesive film, so that hidden cracks in the laminating process can be reduced.

The front packaging adhesive film 5 may be only a front packaging adhesive film or may also be a combination of a front packaging adhesive film and a cover plate. The front encapsulant film and the cover plate have good light transmittance, for example, the light transmittance of the front encapsulant film and the cover plate in the visible light band is greater than or equal to 80%. In the embodiment of the present invention, this is not particularly limited.

The base film portion and the protruding portion protruding from the base film portion in the front encapsulation adhesive film may be integrally formed or formed in steps, and the materials of the base film portion and the protruding portion may be the same or different.

The solar cell 4 is obliquely arranged in the base body part and the protruding part in the connecting layer and in the concave space formed by the base film part and the protruding part in the front packaging adhesive film, so that the solar cell is placed in the groove formed by the connecting layer and the front packaging adhesive film together, the pressure born by the solar cell in the laminating process can be reduced, the hidden crack can be reduced, and the production yield is improved. And the positioning is more accurate, the laying and the alignment of the solar cell are convenient, and the production efficiency is improved.

Alternatively, the material of the base film portion of the front encapsulation adhesive film may be selected from: at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral, or silicone gel.

Optionally, the protruding portions are periodically distributed in the front encapsulant film, and the process is simple, for example, as shown in fig. 2, 13, and 14, the protruding portions are periodically distributed in the front encapsulant film 5.

The embodiment of the invention also provides a preparation method of the photovoltaic module, which comprises the following steps:

step SA1, providing a conductive backplane as mentioned above.

Step SA2, providing a solar cell having a back electrode.

Step SA3, obliquely laying the solar cell in the concave space formed by the base part and the convex part in the connection layer to obtain a module precursor, so that the back electrode of the solar cell is arranged opposite to the conductive region in the connection layer, and the convex surface of the convex part is opposite to the back surface of the solar cell.

Step SA4, laminating the laminate including the assembly precursor to electrically connect the back electrode of the solar cell with the conductive region in the conductive backsheet, wherein the insulating base film of the protruding portion of the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

The stack comprising the foregoing assembly precursors may be: the light-facing surface of the assembly precursor can be further paved with a front packaging adhesive film and a cover plate. Each part of the photovoltaic module refers to the related description, and similar beneficial effects can be achieved, and details are not repeated herein to avoid repetition. The lamination temperature may be 140 ℃ to 160 ℃. In the laminating process in step SA4, the connection layer, the conductive layer, and the back film layer in the conductive backplane may be subjected to a second hot pressing process, so that the conductive particles in each conductive region in the connection layer may be further deformed to increase the contact between the conductive particles adjacent to the conductive region and the adjacent surface, thereby forming a good current path.

It should be noted that, in the preparation method of the photovoltaic module, the front encapsulation adhesive film may be laminated on the backlight surface of the cover plate, then the solar cell is laid on the backlight surface of the front encapsulation adhesive film, and then the conductive back plate is correspondingly disposed on the backlight surface of the solar cell.

The embodiment of the invention also provides another photovoltaic module preparation method, which comprises the following steps:

step SI, providing a connection layer; the connection layer includes: a base portion and a projection portion projecting from the base portion; the connection layer has a conductive region for electrically connecting a back electrode of a solar cell and the conductive line, and an insulating region for blocking adjacent conductive regions; the conductive region and the insulating region both penetrate through the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located within the conductive region.

Step SII, providing a back film layer.

And step SIII, providing a conductive layer.

Step SIV, providing a solar cell having a back electrode.

And SV, sequentially stacking the connecting layer, the conductive layer and the back film layer, and obliquely laying the solar cell in an inner concave space formed by the substrate part and the convex part in the connecting layer to obtain an assembly precursor, so that the back electrode of the solar cell is opposite to the conductive region in the connecting layer, and the convex surface of the convex part is opposite to the back surface of the solar cell.

Step S vi, laminating the stack including the assembly precursor to electrically connect the back electrode of the solar cell with the conductive region in the conductive backsheet, wherein the insulating base film of the convex portion of the connection layer is melted during the lamination process and flows between adjacent solar cells to form an adhesive medium.

In particular, the stack comprising the aforementioned assembly precursors may be: the light-facing surface of the assembly precursor can be further paved with a front packaging adhesive film and a cover plate. In the steps of the method, the connecting layer, the conducting layer and the back membrane layer which form the conducting back plate are not specially subjected to hot-pressing lamination, but the hot-pressing lamination of the connecting layer, the conducting layer and the back membrane layer is completed by means of lamination in the process of forming the photovoltaic module, so that the hot-pressing steps are reduced, the production efficiency is improved, the energy consumption is reduced, and the production cost is reduced. In the method, each part of the photovoltaic module can refer to the related description, and similar beneficial effects can be achieved, and the description is omitted here to avoid repetition.

It should be noted that, in the preparation method of the photovoltaic module, the front encapsulation adhesive film may be laminated on the backlight surface of the cover plate, then the solar cell is laid on the backlight surface of the front encapsulation adhesive film, and then the connection layer, the conductive layer and the back film layer are correspondingly and sequentially arranged on the backlight surface of the solar cell, which is not particularly limited in the embodiment of the present invention.

Optionally, in the two methods for manufacturing the photovoltaic module, the laminating process may include: and (5) performing secondary hot-pressing and laminating. Primarily hot-pressing and attaching the laminated member including the assembly precursor; the stack including the assembly precursor is hot-pressed again. The temperature of the first hot press bonding may be lower than that of the second hot press bonding. For example, the temperature of the first hot press bonding is: and (5) 80-125 ℃, wherein the hot pressing and laminating temperature is as follows: 120 ℃ and 160 ℃. By performing primary hot-press bonding at a lower temperature on the laminated member, the protruding parts of the connecting layers in the conductive back plate and/or the protruding parts of the front packaging adhesive film in the laminated member can be fully melted and uniformly and stably flow to the interconnection part before a crosslinking reaction, so that uniform static pressure is generated. And then, hot pressing and laminating the preheated laminated member again at a higher temperature, and filling and curing the laminated member into gaps of a battery string or assembly under the condition of uniform static pressure, so that gapless connection can be realized, and hidden cracks or cracks can be further reduced.

In the two embodiments of the method, each surface of the front packaging adhesive film in the laminated member may be a plane, or the front packaging adhesive film includes: a base film portion and a projecting portion projecting the base film portion. In the photovoltaic module, the solar cell is obliquely arranged on the base part and the convex part in the connecting layer, and the base film part and the convex part in the front packaging adhesive film, and in an inner concave space formed by the base film part and the convex part together, the convex parts in the connecting layer and the convex parts in the front packaging adhesive film on two sides of the same solar cell are distributed in a staggered mode, and the convex surface of each convex part is opposite to the light facing surface of the solar cell. Namely, the solar cell is obliquely arranged in the concave space formed by the connecting layer and the front packaging adhesive film together.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative rather than restrictive, and it will be apparent to those skilled in the art that many more modifications and variations can be made without departing from the spirit of the invention and the scope of the appended claims.