CN114597278B

CN114597278B - Photovoltaic module and manufacturing method thereof

Info

Publication number: CN114597278B
Application number: CN202210031353.2A
Authority: CN
Inventors: 张军; 何帅; 范靖
Original assignee: Hefei Ja Solar Technology Co ltd; Jingao Yangzhou New Energy Co ltd; Shanghai Ja Solar Pv Technology Co ltd
Current assignee: Hefei Ja Solar Technology Co ltd; Jingao Yangzhou New Energy Co ltd; Shanghai Ja Solar Pv Technology Co ltd
Priority date: 2022-01-12
Filing date: 2022-01-12
Publication date: 2024-06-25
Anticipated expiration: 2042-01-12
Also published as: CN114597278A

Abstract

The invention discloses a photovoltaic module and a manufacturing method thereof. The photovoltaic module includes: a plurality of battery strings, bus bars, packaging adhesive films and a backboard with a plurality of reflecting film layers, wherein the battery strings, the bus bars and the packaging adhesive films are respectively arranged on two sides of the bus bars; each battery string comprises a plurality of battery pieces connected in series through welding strips, and each battery string is connected with the bus bar through the welding strips; the plurality of reflecting film layers are covered on the backboard, and each reflecting film layer corresponds to a gap between two adjacent battery strings; among the plurality of battery strings, a first battery string arranged on one side of the bus bar and a second battery string arranged on the other side of the bus bar are arranged in a staggered manner; among the plurality of reflecting film layers, the first reflecting film layer covered between two adjacent first battery strings and the second reflecting film layer covered between two adjacent second battery strings are arranged in a staggered way. The photovoltaic module can enable the position of the reflecting film layer to accurately cover the cell gap under the condition that the reflecting film layer is not widened.

Description

Photovoltaic module and manufacturing method thereof

Technical Field

The invention relates to a photovoltaic module and a manufacturing method thereof.

Background

Along with the development of assembly technology, the double-sided assembly technology is becoming the mainstream, and the double-sided assembly on the market is mainly formed by laminating and packaging materials such as a glass cover plate, an upper packaging adhesive layer, a double-sided battery piece, a lower packaging adhesive layer, a transparent back plate made of glass or high polymer materials. In order to increase the power gain, a reflecting film layer is arranged on the inner side of the backboard, the position of the reflecting film layer corresponds to the cell gap, and the reflecting film layer reflects light passing through the cell gap back to be reused.

However, the position of the reflecting film layer cannot accurately cover the cell gap, so that the problem of light leakage exists. If the problem of light leakage is solved by widening the reflective film layer, the back surface rate of the assembly is lowered.

Disclosure of Invention

Accordingly, the present invention is directed to a photovoltaic module and a method for manufacturing the same, which solve the technical problems in the prior art.

In order to solve the technical problems, the invention provides the following technical scheme:

In a first aspect of the present invention, an embodiment of the present invention provides a photovoltaic module, including a plurality of cell strings disposed on both sides of a bus bar, the bus bar, a packaging film, and a back plate having a plurality of reflective film layers; wherein,

Each of the battery strings includes a plurality of battery pieces connected in series by a solder ribbon, and each of the battery strings is connected with the bus bar by the solder ribbon;

The plurality of reflecting film layers are covered on the backboard, and each reflecting film layer corresponds to a gap between two adjacent battery strings;

Among the plurality of battery strings, a first battery string arranged on one side of the bus bar and a second battery string arranged on the other side of the bus bar are arranged in a staggered manner;

Among the plurality of reflecting film layers, a first reflecting film layer arranged between two adjacent first battery strings and a second reflecting film layer arranged between two adjacent second battery strings are arranged in a staggered mode.

In some embodiments of the invention, the cell strings are offset by the same distance as the reflective film layers.

In some embodiments of the invention, the ratio of the string spacing between the strings of cells to the misalignment distance of the reflective film layer is (9-18): 10;

And/or the number of the groups of groups,

Along the width direction of the back plate, the ratio of the string spacing between the battery strings to the width of the reflecting film layer is (2-3): 10.

In some embodiments of the invention, the reflective film layer has a misalignment distance of 0.1 to 2mm and/or a width of 5 to 15mm along the width of the back plate.

In some embodiments of the invention, the orthographic projection of the gap between the cells onto the back plate is located within the reflective film layer.

In some embodiments of the present invention, if the dimension elongation of the back sheet after lamination of the back sheet is X, the ratio of the pitch of the reflective film layer before lamination of the back sheet to the pitch of the reflective film layer after lamination of the back sheet is 1 (1+x).

In some embodiments of the invention, the reflective film layer has a width of 5 to 15mm along the length of the back plate.

In some embodiments of the invention, the reflective film layer includes a reflective powder, an inorganic binder, and an aqueous resin.

In some embodiments of the invention, the reflective powder is selected from at least one of calcium carbonate powder, silica powder, and titanium white powder;

And/or the number of the groups of groups,

The inorganic binder is glass powder.

In a second aspect of the present invention, an embodiment of the present invention provides a method for manufacturing a photovoltaic module, including:

step1, covering a plurality of reflecting film layers on a backboard in a dislocation mode;

step 2, connecting the battery pieces in series into a battery string through a welding belt, and connecting the battery strings with a bus bar;

and 3, sequentially arranging the backboard covered with the reflecting film layer, the lower packaging adhesive layer, the battery string, the upper packaging adhesive layer and the glass cover plate, and then laminating to form the photovoltaic module.

The technical scheme of the embodiment of the invention has the following advantages or beneficial effects: according to the photovoltaic module provided by the embodiment of the invention, the first reflecting film layers and the second reflecting film layers on two sides of the bus bar are arranged in a staggered mode to replace the first reflecting film layers and the second reflecting film layers on two sides of the bus bar in the prior art to be positioned on the same straight line, so that the reflecting film layers can accurately cover the gaps of the battery pieces, and light passing through the gaps of the battery pieces is reflected back for secondary utilization, so that the problem of light leakage of the gaps of the battery pieces is reduced.

In addition, after the reflecting film layers are arranged in a staggered mode, the light leakage problem of the photovoltaic module is remarkably improved, and in order to achieve the consideration of the back surface rate, the width of the reflecting film layers is properly reduced under the condition that the module light leakage does not occur on the basis of staggered arrangement of the reflecting film layers, and then the back surface shielding of a battery piece is reduced, so that the back surface rate is increased, the material consumption of the reflecting film layers is reduced, and the cost is reduced.

In addition, considering that the distance between the reflecting film layers can be extended after the components are laminated, the embodiment of the invention performs shrinkage design on the distance between the reflecting film layers, namely reduces the distance between the reflecting film layers, so that the positions of the reflecting film layers after the components are laminated can more accurately cover the gaps of the battery plates, and light leakage is further reduced. After the interval of the reflecting film layers is shrunk, the light leakage problem of the photovoltaic module is remarkably improved, and in order to achieve the back surface rate, the width of the reflecting film layers is properly reduced under the condition that the module light leakage does not occur on the basis of shrinking the interval of the reflecting film layers, and then the back surface shielding of a battery piece is reduced, so that the back surface rate is increased, the material consumption of the reflecting film layers is reduced, and the cost is reduced.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an arrangement of a prior art bus bar, solder strip, battery tab, and reflective film layer;

FIG. 2 is a schematic diagram of an arrangement of a prior art battery sheet and a reflective film layer;

FIG. 3 is a schematic view of an arrangement of bus bars, solder strips, battery cells, and reflective film layers according to an embodiment of the invention;

FIG. 4 is a schematic view of an arrangement of a battery sheet and a reflective film layer according to an embodiment of the present invention;

FIG. 5 is an extended schematic view of a back plate according to an embodiment of the invention;

FIG. 6 is an illustration of an extension of the reflective film layer spacing according to an embodiment of the present invention;

fig. 7 is a schematic flow chart of a method for manufacturing a photovoltaic module according to an embodiment of the present invention.

The reference numerals are as follows:

Prior Art

10-Bus bars;

11-welding a tape;

12-cell pieces;

13-battery strings;

131-string spacing;

14-a reflective film layer;

The invention is that

30-Bus bars;

31-welding the tape;

32-cell pieces;

33-battery strings;

331-a first battery string;

332-a second battery string;

34-a reflective film layer;

341-a first reflective film layer;

342-a second reflective film layer;

40-backboard.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

In the actual welding process, considering the limited width and welding effect of the bus bar 10, the reserved welding strips 11 on the battery sheets at both sides of the bus bar 10 are welded to the bus bar 10 in a staggered manner, as shown in fig. 1, which causes the string spacing 131 of the battery strings 13 at both sides of the bus bar to be staggered. In the prior art, as shown in fig. 2 (bus bars and solder strips are omitted in fig. 2 for clearly showing the positional relationship between the battery cells and the reflective film layers), the reflective film layer 14 on the back plate is merely disposed symmetrically, so that the position of the reflective film layer 14 cannot precisely cover the battery cell gap, or a problem of light leakage is caused, or the back surface rate needs to be sacrificed by widening the reflective film layer.

Compared with the existing photovoltaic module, the photovoltaic module provided by the embodiment of the invention has the advantages that the position of the reflecting film layer can accurately cover the cell gap under the condition that the reflecting film layer is not widened, so that the light leakage problem is avoided.

Fig. 3 is a schematic view of an arrangement structure of a bus bar, a solder strip, a battery cell, and a reflective film layer according to an embodiment of the present invention, and fig. 4 is a schematic view of an arrangement structure of a battery cell and a reflective film layer according to an embodiment of the present invention (the bus bar and the solder strip are omitted in fig. 4 in order to clearly show a positional relationship of the battery cell and the reflective film layer). As shown in fig. 3-4, in the embodiment of the invention, the photovoltaic module is divided into a plurality of cell strings 33 disposed on both sides of the bus bar 30, a packaging film, and a back sheet 40 having a plurality of reflective film layers 34; wherein each cell string 33 includes a plurality of cell pieces 32 connected in series by a solder ribbon 31, and each cell string 33 is connected to the bus bar 30 by the solder ribbon 31; the plurality of reflecting film layers are arranged on the backboard, and each reflecting film layer corresponds to a gap between two adjacent battery strings 33; among the plurality of battery strings 33, the first battery string 331 disposed at one side of the bus bar 30 is staggered with the second battery string 332 disposed at the other side of the bus bar 30; among the plurality of reflective film layers, the first reflective film layers 341 disposed between the adjacent two first cell strings 331 are staggered with the second reflective film layers 342 disposed between the adjacent two second cell strings 332. Considering that the string pitches of the first battery strings 331 and the second battery strings 332 on both sides of the bus bar 30 are staggered, in order to accurately cover the respective cell gaps at the positions of the reflective film layers 34, the reflective film layers 34 are optimized in the embodiment of the present invention, and the arrangement manner of the first reflective film layers 341 and the second reflective film layers 342 on both sides of the bus bar 30 is adjusted, so that the first reflective film layers 341 and the second reflective film layers 342 on both sides of the bus bar 30 are also arranged in a staggered manner.

Since the first and second reflective film layers 341 and 342 on both sides of the bus bar 30 are also disposed in a staggered manner, the reflective film layer 34 can precisely cover the cell gap, and reflect the light passing through the cell gap back for reuse, thereby reducing the problem of light leakage in the cell gap.

In the prior art, the first reflective film layer and the second reflective film layer on two sides of the bus bar are positioned on the same straight line, and the first reflective film layer and the second reflective film layer are arranged in a staggered manner, so that the first reflective film layer and the second reflective film layer which are originally positioned on the same straight line are staggered.

It should be noted that, in the embodiment of the present invention, as shown in fig. 3, the first battery string on the left side of the bus bar is taken as the first battery string, and the second battery string on the right side of the bus bar is taken as the second battery string; however, the battery string on the right side of the bus bar may be used as the first battery string, and the battery string on the left side of the bus bar may be used as the second battery string, which is not limited in the embodiment of the present invention. Similarly, the reflective film layer on the left side of the bus bar can be used as a first reflective film layer, and the reflective film layer on the right side of the bus bar can be used as a second reflective film layer; the reflective film layer on the right side of the bus bar may be used as the first reflective film layer, and the reflective film layer on the left side of the bus bar may be used as the second reflective film layer.

In some embodiments of the present invention, as shown in fig. 4, the misalignment distance of the cell strings 33 is the same as the misalignment distance of the reflective film layers 34, so that each reflective film layer can be ensured to precisely cover the cell string gap corresponding thereto.

As shown in fig. 4, the misalignment distance of the reflective film layer 34 is a distance d1 between the center line of the first reflective film layer 341 and the center line of the second reflective film layer 342 on both sides of the bus bar 30. In the prior art, the distance d1=0 between the center line of the first reflective film layer 341 and the center line of the second reflective film layer 342 on both sides of the bus bar 30, and the first reflective film layer 341 and the second reflective film layer 342 are arranged in a staggered manner, and the staggered distance d1 of the first reflective film layer 341 and the second reflective film layer 342 is the same as the staggered distance of the cell string 33.

In some embodiments of the present invention, the ratio of the string spacing between the cell strings 33 to the misalignment distance of the reflective film layer 34 is (0.9-1.8): 1, the misalignment distance of the reflective film layer 34 is related to the string spacing between the cell strings 33, and the misalignment distance of the reflective film layer 34 can be controlled within a suitable range according to the string spacing between the cell strings 33, so that it can be ensured that the reflective film layer can precisely cover the cell gap, thereby reducing the light leakage problem. As shown in fig. 4, if the string pitch d2 between the battery strings 33 is 1.8mm, the misalignment distance d1 of the reflective film layer 34 may be 0.2mm, 0.5mm, 1mm, 1.2mm, 2mm, or the like; if the string spacing d2 between the battery strings 33 is 2mm, the misalignment distance d1 of the reflective film layer 34 may be 0.12mm, 0.45mm, 1.3mm, 1.8mm, 2.2mm, or the like; if the string spacing d2 between the battery strings 33 is 1.5mm, the misalignment distance d1 of the reflective film layer 34 may be 0.1mm, 0.7mm, 1mm, 1.4mm, 1.6mm, or the like; in these embodiments, the reflective film layer can precisely cover the cell gap, and reflect light passing through the cell gap back to be reused, thereby reducing the light leakage problem.

Since the reflective film layer 34 is dislocated along the width direction of the back plate 40, controlling the size of the dislocating distance of the reflective film layer 34 by the size of the string pitch can ensure that the reflective film layer can accurately cover the cell gap.

Alternatively, the offset distance of the reflective film layer 34 is 0.1-2 mm, so that the reflective film layer 34 can precisely cover the cell gap, and the light passing through the cell gap is reflected back for secondary use, thereby reducing the problem of light leakage from the cell gap. The offset distance of the reflective film layer 34 is typically, but not limited to, preferably 0.2mm, 0.5mm, 1mm, 1.3mm, 1.45mm, 1.6mm, or 1.8mm, and in these embodiments, the reflective film layer 34 is arranged in an offset manner, so that the cell spacing can be precisely covered, and the light passing through the cell gap is reflected back for reuse, so that the problem of light leakage in the cell gap is significantly reduced.

In the prior art, the problem of light leakage of the photovoltaic module is generally solved by widening the reflecting film layer, which can lead to more shielding of the back of the battery piece and influence the back power generation. In the embodiment, after the reflecting film layers are arranged in a staggered mode, the light leakage problem of the photovoltaic module is remarkably improved, and in order to achieve the consideration of the back surface rate, the width of the reflecting film layers is properly reduced under the condition that the module light leakage does not occur on the basis of the staggered arrangement of the reflecting film layers, so that the back surface shielding of a battery piece is reduced, the back surface rate is increased, the material consumption of the reflecting film layers is reduced, and the cost is reduced.

In other embodiments of the present invention, the ratio of the string spacing between the cell strings 33 to the width of the reflective film layer 34 along the width direction y of the back plate 40 is (2-3): 10, which not only solves the problem of light leakage of the module, but also properly reduces the width of the reflective film layer 34. The width of the reflective film layer 34 is related to the string spacing between the battery strings 33, and the width of the reflective film layer 34 can be controlled within a proper range according to the string spacing between the battery strings 33, so that the reflective film layer can be ensured to accurately cover the battery piece gap, and the shielding of the back of the battery piece can be reduced. As shown in fig. 4, if the string spacing d2 between the battery strings 33 is 1.8mm, the width d3 of the reflective film layer 34 may be 6mm, 6.5mm, 7mm, 8.8mm, 9mm, or the like; if the string spacing d2 between the battery strings 33 is 2mm, the width d3 of the reflective film layer 34 may be 6.7mm, 7.3mm, 8mm, 9.5mm, 10mm, or the like; if the string spacing d2 between the battery strings 33 is 1.5mm, the width d3 of the reflective film layer 34 may be 5mm, 5.6mm, 6mm, 6.9mm, 7.5mm, or the like; in these embodiments, the reflective film layer can accurately cover the cell gap while also reducing cell backside shadowing, thereby increasing backside rate, reducing reflective film layer materials, and reducing cost.

Alternatively, as shown in fig. 4, the width d3 of the reflective film layer 34 is 5 to 15mm along the width direction y of the back plate 40, so that not only can the reflective film layer 34 be ensured to precisely cover the string spacing between the battery strings 33, but also the width of the reflective film layer 34 can be appropriately reduced, thereby reducing the back shading of the battery pieces. Of these, the width d3 of the reflective film layer 34 is typically, but not limited to, preferably 5mm, 6mm, 6.5mm, 6.8mm, 7.8mm, 8.3mm, 8.7mm, 9mm, 12mm, 15mm, etc., and in these embodiments, the back shading of the cell sheet can be reduced due to the reduced width of the reflective film layer 34, thereby increasing the back rate, reducing the reflective film layer material, and reducing the cost.

In the embodiment of the invention, the front projection of the gaps between the battery pieces 32 on the back plate 40 is located in the reflective film layer 34, and the first reflective film layers 341 and the second reflective film layers 342 on two sides of the bus bar 30 are arranged in a staggered manner, and meanwhile, the width of the reflective film layers 40 is properly reduced, so that the front projection of the gaps between the battery pieces 32 on the back plate 40 is located in the reflective film layer 34, and therefore, the reflective film layer 34 not only can accurately cover the gaps of the battery pieces, but also can reduce the back shielding of the battery pieces, thereby increasing the back rate, reducing the material consumption of the reflective film layers and reducing the cost.

The back sheet 40 may be laminated with transparent glass, or may be laminated with a polymer material such as polyethylene terephthalate or polyvinylidene fluoride. However, if the lamination is performed using a polymer material, as shown in fig. 5, the back sheet 40 is subjected to high temperature and high pressure and the flow of the contact surface polyolefin film is involved in the pulling action during the lamination of the assembly, and the size of the back sheet 40 is easily extended to the periphery. Since the reflective film 34 is disposed on the back plate 40, as shown in fig. 6, the distance d4 between the reflective film 34 extends along the length direction x of the back plate 40, and the distance d5 between the reflective film 34 extends along the width direction y of the back plate 40, which results in a shift of the position of the reflective film 34, and thus the reflective film 34 cannot precisely cover the cell gap after the lamination of the components, resulting in light leakage.

Considering that the distance between the reflective film layers 34 will extend after the lamination of the components, the embodiment of the invention performs shrinkage design on the distances d4 and d5 between the reflective film layers 34, that is, reduces the distances d4 and d5 between the reflective film layers 34, so that the positions of the reflective film layers 34 after the lamination of the components can cover the gaps of the battery plates more accurately, thereby further reducing light leakage.

In some embodiments of the present invention, if the back sheet 40 is a transparent back sheet made of a polymer material, the ratio of the pitch of the reflective film layer 34 before laminating the back sheet 40 to the pitch of the reflective film layer 34 after laminating the back sheet 40 is 1 (1.0001-1.01), so that the position of the reflective film layer 34 after laminating the component can be ensured to precisely cover the cell gap, and the problem of light leakage of the component can be further improved. For example, in the case where the back sheet 40 is not considered to be extended, the pitch of the reflective film layer 34 is Lmm, and then the pitch of the reflective film layer 34 is set to L/(1.0001 to 1.01) before the back sheet 40 is laminated, and after the back sheet 40 is laminated, since the back sheet 40 is extended to the periphery, the pitch of the reflective film layer 34 is Lmm, which covers precisely the cell pitch, thereby remarkably reducing light leakage.

Since the positional deviation of the reflective film layer 34 is caused by the extension of the back plate 40, in order to ensure that the reflective film layer 34 can precisely cover the cell pitch after the lamination of the components, the ratio of the pitches of the reflective film layer 34 before and after lamination of the back plate 40 is determined by the dimensional extensibility of the back plate 40. In other embodiments of the present invention, if the dimensional extensibility of the back sheet 40 is X after lamination of the back sheet 40, the ratio of the pitch of the reflective film layer 34 before lamination of the back sheet 40 to the pitch of the reflective film layer 34 after lamination of the back sheet 40 is 1 (1+X), thereby ensuring that the position of the reflective film layer 34 after lamination of the assembly can accurately cover the cell gap.

In the embodiment, after the space between the reflecting film layers is shrunk, the light leakage problem of the photovoltaic module is remarkably improved, and in order to achieve the back surface rate, the width of the reflecting film layers is properly reduced under the condition that the light leakage of the module does not occur on the basis of shrinking the space between the reflecting film layers, so that the back surface shielding of a battery piece is reduced, the back surface rate is increased, the material consumption of the reflecting film layers is reduced, and the cost is reduced.

In other embodiments of the present invention, the ratio of the spacing between the cells 32 (including the string spacing and/or the sheet spacing) to the width of the reflective film layer 34 is (2-3): 10, which not only solves the problem of component light leakage, but also properly reduces the width of the reflective film layer 34. The width of the reflective film 34 is related to the spacing between the battery plates 32, and the width of the reflective film 34 can be controlled within a proper range according to the spacing between the battery plates 32, so that the reflective film can accurately cover the gap between the battery plates, and shielding of the back of the battery plates can be reduced. If the spacing between the cells 32 is 1.8mm, the width of the reflective film layer 34 may be 6.1mm, 6.4mm, 7.7mm, 8mm, 9mm, or the like; if the spacing between the battery pieces 32 is 2mm, the width of the reflective film layer 34 may be 6.8mm, 7.5mm, 9mm, 9.8mm, 10mm, or the like; if the spacing between the battery plates 32 is 1.5mm, the width of the reflective film layer 34 may be 5.3mm, 5.8mm, 6.6mm, 7mm, 7.3mm, or the like; in these embodiments, the reflective film layer can accurately cover the cell gap while also reducing cell backside shadowing, thereby increasing backside rate, reducing reflective film layer materials, and reducing cost. It should be noted that in these embodiments, the cell pitch is in the same direction as the reflective film layer width, e.g., both along the back plate width direction y (string pitch), or both along the back plate length direction x (sheet pitch).

Optionally, the width of the reflective film layer 34 is 5-15 mm, so that not only can the reflective film layer 34 cover the cell spacing accurately, but also the width of the reflective film layer 34 can be reduced appropriately, thereby reducing the back shielding of the cell. Of these, the width of the reflective film layer 34 is typically, but not limited to, preferably 5mm, 6mm, 6.4mm, 6.5mm, 7mm, 7.6mm, 8.5mm, 8.9mm, 9mm, 11mm, 13mm, 15mm, or the like, and in these embodiments, due to the reduced width of the reflective film layer 34, the cell backside shielding can be reduced, thereby increasing the backside ratio, reducing the reflective film layer material, and reducing the cost.

It should be noted that, the cross section of the back plate 40 is generally rectangular, and the length of the back plate 40 in the length direction is significantly longer than the length of the back plate in the width direction, in some embodiments of the present invention, only the length direction of the back plate 40 may be considered, that is, along the width direction y of the back plate 40, the reflective film layers 34 are arranged in a staggered manner, but the space d3 between the reflective film layers 34 need not be reduced; the distance d4 between the reflective film layers 34 is reduced along the length direction x of the back plate 40, so that the position of the reflective film layers 34 after lamination of the components can be ensured to accurately cover the cell gap, and the light leakage of the components is remarkably reduced.

In another embodiment of the present invention, as shown in fig. 6, the reflective film layers 34 are arranged in a staggered manner along the width direction y of the back plate 40 while narrowing the pitch d5 of the reflective film layers 34; along the length direction x of the back plate 40, the pitch d4 of the reflective film layer 34 is reduced. In these embodiments, the reflective film layer 34 is optimized in two ways simultaneously: 1) The reflective film layers 34 are arranged in a staggered manner; 2) Narrowing the pitch of the reflective film layer 34; based on the optimization of these two aspects, the component laminated reflective film layer 34 can cover the cell gap more accurately, and reflect back through the cell gap to be reused, so that the component light leakage problem is significantly reduced.

Therefore, under the condition that the defective rate of light leakage is the same, the reflecting film layers are arranged in a staggered mode and the intervals between the reflecting film layers are shrunk, so that the width of the reflecting film layers can be further narrowed to the narrowest, and the back shielding of the battery piece can be reduced to the minimum under the condition that the light leakage of the component does not occur, thereby obviously increasing the back rate, reducing the material consumption of the reflecting film layers and reducing the cost.

In some embodiments of the present invention, the reflective film layer includes a reflective powder, an inorganic binder, and an aqueous resin, where the reflective powder and the inorganic binder are dispersed in the aqueous resin, and a dense inorganic binder-reflective powder pattern layer can be constructed on the surface of the back plate, so as to reflect light. The reflective film layer material can be coated or coated by roller coating, spraying and the like, and after the coating process is finished, the back plate coated with the reflective film layer material is subjected to heat treatment to realize surface drying, and then is heated and cured at high temperature. The reflectivity of the coated back-sheet can be varied by adjusting the coating thickness.

Optionally, the reflective powder is at least one selected from calcium carbonate powder, silicon dioxide powder or titanium white powder, and the reflective powder has good reflectivity and can be uniformly dispersed in the aqueous resin, so that a uniform reflective film layer is formed on the surface of the back plate. Optionally, the inorganic binder is glass powder, which is helpful for improving the cohesiveness of the reflective film layer and the backboard, and the glass powder is uniformly dispersed in the aqueous resin.

In order to help understand the scheme of the present invention, the following describes in detail the photovoltaic module provided by the present invention in several specific embodiments.

Example 1

The battery pieces on two sides of the bus bar are arranged in a staggered mode according to 1mm, the battery piece spacing along the length direction of the back plate and the battery string spacing along the width direction of the back plate are 1.8mm, and the size of each battery piece is 91mm multiplied by 182mm.

As shown in fig. 3-4, the reflective film layers on two sides of the bus bar are arranged in a staggered mode by 1mm, the width of the reflective film layer is 9mm, and the single-side back of the battery piece is shielded by 3.6mm. The spacing of the reflective film layers is 91-3.6-3.6=83.8 mm, 182-3.6-3.6=174.8 mm.

Example 2

The cell pitch along the length direction of the back plate and the cell string pitch along the width direction of the back plate were each 1.8mm, and the dimensions of individual cells were 91mm×182mm. The reflecting film layers on the two sides of the bus bar are positioned on the same straight line.

Since the back plate extends by 0.2% after lamination, the spacing of the reflective film layers is shrunk by 0.2% before lamination, the width of the reflective film layers is arranged according to 8mm, the single-sided back shielding of the battery piece is 3.1mm, the spacing of the reflective film layers is (91-3.1-3.1) × (1-0.2%) = 84.6304mm, (182-3.1-3.1) × (1-0.2%) = 175.4484mm.

Example 3 (combination of example 1 and example 2)

As shown in fig. 6, the spacing of the reflective film layers was shrunk by 0.2% before lamination, the width of the reflective film layers was arranged in 7mm, the single-sided back of the battery sheet was masked down to 2.6mm, the spacing of the reflective film layers was (91-2.6-2.6) × (1-0.2%) = 85.6284mm, (182-2.6-2.6) × (1-0.2%) = 176.4464mm.

Example 4

As shown in fig. 3-4, the reflective film layers on two sides of the bus bar are arranged in a staggered manner by 0.5mm, the width of the reflective film layer is 9.5mm, and the single-side back of the battery piece is shielded by 3.85mm. The spacing of the reflective film layers is 91-3.85-3.85=83.3 mm, 182-3.85-3.85=174.3 mm.

Example 5:

Since the back sheet is 0.1% extended in size after lamination, the spacing of the reflective film layers is shrunk by 0.1% before lamination, the width of the reflective film layers is arranged according to 8.8mm, the single-sided back shielding of the battery piece is 3.5mm, the spacing of the reflective film layers is (91-3.5-3.5) × (1-0.1%) = 83.916mm, (182-3.5-3.5) × (1-0.1%) = 174.825mm.

Example 6 (combination of example 4 and example 5)

The battery pieces on two sides of the bus bar are arranged in a staggered mode by 0.5mm, the battery piece spacing along the length direction of the back plate and the battery string spacing along the width direction of the back plate are 1.8mm, and the size of each battery piece is 91mm multiplied by 182mm.

As shown in fig. 3 to 4 and 6, the spacing of the reflective film layers was shrunk by 0.1% before lamination, the width of the reflective film layers was arranged to 7.5mm, the single-sided back side shading of the battery sheet was reduced to 2.85mm, the spacing of the reflective film layers was (91-2.85-2.85) × (1-0.1%) = 85.2147mm, (182-2.85-2.85) × (1-0.1%) = 176.1237mm.

Comparative example 1

Photovoltaic modules of the prior art:

As shown in figures 1-2, the reflecting film layers on two sides of the bus bar are positioned on the same straight line, the width of the reflecting film layer is more than 15mm (such as 15mm,16mm,20mm or 22mm, etc.), normal quantity production of the assembly can be met, light leakage is avoided, the single-side back of the battery piece is shielded by the width of more than 6.6mm, the back rate is influenced, and the material cost of the reflecting film layer is higher.

The back surface ratios of the photovoltaic modules prepared in the above examples and the photovoltaic modules in the prior art are shown in the following table:

	Back face rate
		Example 1	66％
Example 2	68％
		Example 3	71％
Example 4	65％
		Example 5	66％
Example 6	69％
		Comparative example 1	≤64％

As can be seen from the above data, compared with the photovoltaic module in the prior art, the photovoltaic module of the embodiment of the invention has significantly improved back surface rate due to the reduced width of the reflective film layer.

The gap light leakage defective rate of the photovoltaic module prepared by the embodiment and the cell of the photovoltaic module in the prior art is shown in the following table:

	Defective rate of light leakage
		Example 1	0.5％
Example 2	0.3％
		Example 3	0.1％
Example 4	0.4％
		Example 5	0.4％
Example 6	0.3％
		Comparative example 1	≥0.9％

As can be seen from the above data, compared with the photovoltaic module in the prior art, the photovoltaic module of the embodiment of the invention adopts the dislocation mode to arrange and/or reduce the interval between the reflecting film layers, so that the reflecting film layers can accurately cover the gaps of the battery cells, and the light leakage defective rate of the photovoltaic module is obviously reduced.

As shown in fig. 7, the manufacturing method of the photovoltaic module provided by the above embodiments may include the following steps:

In step 701, a plurality of reflective film layers are coated on the back plate in a dislocation mode.

Firstly, a reflective film layer is arranged on a backboard according to the installation position of the bus bar, so that a first reflective film layer on one side of the bus bar and a second reflective film layer on the other side of the bus bar are arranged in a staggered mode. The reflective film layer material can be coated or coated by roller coating, spraying and the like, and after the coating process is finished, the back plate coated with the reflective film layer material is subjected to heat treatment to realize surface drying, and then is heated and cured at high temperature. The reflecting film layer comprises reflecting powder, inorganic connecting materials and water-based resin, wherein the reflecting powder and the inorganic connecting materials are dispersed in the water-based resin, so that a compact inorganic connecting material-reflecting powder layer can be constructed on the surface of the backboard, and light reflection can be realized. Optionally, the reflective powder is at least one selected from the group consisting of calcium carbonate powder, silica powder and titanium white powder, and these reflective powders have a good reflectivity and can be uniformly dispersed in the aqueous resin, contributing to the formation of a uniform reflective film layer on the surface of the back sheet. Optionally, the inorganic binder is glass powder, which is helpful for improving the cohesiveness of the reflective film layer and the backboard, and the glass powder is uniformly dispersed in the aqueous resin.

After the reflecting film layers are arranged in a staggered mode, the light leakage problem of the photovoltaic module is remarkably improved, and in order to achieve the effect of considering the back surface rate, the width of the reflecting film layers is properly reduced under the condition that the module light leakage does not occur on the basis of staggered arrangement of the reflecting film layers, and then the back surface shielding of a battery piece is reduced, so that the back surface rate is increased, the material consumption of the reflecting film layers is reduced, and the cost is reduced.

In other embodiments of the present invention, considering that the distance between the reflective film layers may extend after the lamination of the components, the embodiment of the present invention performs the shrinkage design on the distance between the reflective film layers, so that the position of the reflective film layers after the lamination of the components may cover the cell gap more precisely, thereby further reducing the light leakage. If the dimension elongation of the back plate after lamination of the back plate is X, the ratio of the spacing of the reflective film layers before lamination of the back plate to the spacing of the reflective film layers after lamination of the back plate is 1 (1+X), thereby ensuring that the positions of the reflective film layers after lamination of the component can accurately cover the cell gaps.

Optionally, the ratio of the spacing between the battery pieces (including the string spacing and/or the piece spacing) to the width of the reflecting film layer is (2-3): 10, so that the problem of light leakage of the assembly can be solved, and the width of the reflecting film layer can be properly reduced.

In step 702, the battery pieces are connected in series into a battery string through a welding strip and are connected with a bus bar.

Cutting the battery piece into a layout with a set size, such as 91mm multiplied by 182mm, by a lossless laser cutting technology, then adopting an infrared welding technology, welding front and back main electrodes of the battery piece by a welding belt at 230 ℃, connecting the single battery piece in series into a battery string, and typesetting the battery string into a program setting layout.

And step 703, sequentially arranging the back plate covered with the reflecting film layer, the lower packaging adhesive layer, the battery string, the upper packaging adhesive layer and the glass cover plate, and then laminating to form the photovoltaic module.

Step 703 may specifically include the following steps:

Step (1), automatic lamination: the main structure (back plate-lower packaging adhesive layer-battery string-upper packaging adhesive layer-glass cover plate) of the assembly is paved layer by layer through an automatic paving machine, bus bars are welded to enable the battery strings to be integrally connected in series, then the bus bars are led out, and a positioning adhesive tape is added.

Step (2), front EL, appearance inspection: and (3) supplying 5-9A of current to the series-connected semi-finished product assemblies, shooting infrared pictures of the assemblies by using an infrared camera, checking defects such as hidden cracks, dislocation, cold joint, foreign matters and the like, and if the defects are found, repairing the semi-finished product stacks.

Step (3), double-cavity lamination: and vacuumizing in the laminating cavity is completed, heating the upper packaging adhesive layer and the lower packaging adhesive layer to be in a molten state through heating, and pressurizing through the adhesive plate to enable the upper packaging adhesive layer and the lower packaging adhesive layer to reach a crosslinking structure.

Step (4), automatic edging: and (3) laminating the overflowed packaging adhesive layer and the exceeded backboard by an automatic edging machine, edging to be neat and smooth with the edge of the glass cover plate.

Step (5), appearance inspection: the degree of defects in the appearance of the laminate was checked by mirror surface.

Step (6), automatic framing: the automatic framing machine is used for filling glue into the aluminum alloy frame groove body, and then the frames are installed on the periphery of the laminated piece in a mode of corner key buckling.

Step (7), junction box installation: and the back contact surface of the wire box is glued and fixed on the back of the component.

Step (8), welding a junction box: and tin-adding and welding the lead-out bus bar and the terminal block.

Step (9), junction box glue filling: the glue groove inside the wire box is filled and sealed by silica gel, and the silica gel should seal all wiring terminals.

The photovoltaic module manufactured by the method can accurately cover the cell gap, and light passing through the cell gap is reflected back for secondary use, so that the problem of light leakage of the cell gap is reduced, the width of the reflecting film layer can be properly reduced under the condition that the module light leakage does not occur, and then the shielding of the back of the cell is reduced, so that the back rate is increased, the material consumption of the reflecting film layer is reduced, and the cost is reduced.

Those of ordinary skill in the art will appreciate that: the discussion of any of the embodiments above is merely exemplary and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples; combinations of features of the above embodiments or in different embodiments are also possible within the idea of the invention, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. of the present invention should be included in the scope of the present invention.

Claims

1. The photovoltaic module is characterized by comprising a plurality of battery strings (33) which are respectively arranged at two sides of a bus bar (30), the bus bar (30), an encapsulation adhesive film and a back plate (40) with a plurality of reflection film layers (34); wherein,

Each of the battery strings (33) includes a plurality of battery pieces (32) connected in series by a solder ribbon (31), and each of the battery strings (33) is connected with the bus bar (30) by the solder ribbon (31);

The back plate is covered by a plurality of reflecting film layers, and each reflecting film layer corresponds to a gap between two adjacent battery strings (33);

Among the plurality of battery strings (33), a first battery string (331) provided on one side of the bus bar (30) is staggered with a second battery string (332) provided on the other side of the bus bar (30);

Among the plurality of reflection film layers, a first reflection film layer (341) arranged between two adjacent first cell strings (331) and a second reflection film layer (342) arranged between two adjacent second cell strings (332) are arranged in a staggered manner.

2. The photovoltaic module according to claim 1, characterized in that the cell strings (33) are offset by the same distance as the reflective film layers (34).

3. The photovoltaic module according to claim 1 or 2, characterized in that the ratio of the string spacing between the strings (33) to the misalignment distance of the reflective film layer (34) is (9-18): 10.

4. A photovoltaic module according to claim 3, characterized in that the offset distance of the reflective film layer (34) is 0.1-2 mm.

5. The photovoltaic module according to claim 1 or 2, wherein a ratio of a string pitch between the cell strings (33) to a width of the reflective film layer (34) along a width direction of the back sheet (40) is (2 to 3): 10.

6. The photovoltaic module according to claim 5, wherein the width of the reflective film layer (34) is 5 to 15mm along the width direction of the back sheet (40).

7. The photovoltaic module according to claim 1, characterized in that the orthographic projection of the gap between the cells (32) onto the backsheet (40) is located within the reflective film layer (34).

8. The photovoltaic module according to claim 1, wherein if the dimensional elongation of the backsheet (40) is X after lamination of the backsheet (40), the ratio of the pitch of the reflective film layer (34) before lamination of the backsheet (40) to the pitch of the reflective film layer (34) after lamination of the backsheet (40) is 1 (1+x).

9. The photovoltaic module according to claim 8, wherein the width of the reflective film layer (34) is 5-15 mm along the length of the backsheet (40).

10. The photovoltaic module of claim 1, wherein the reflective film layer (34) comprises a reflective powder, an inorganic binder, and an aqueous resin.

11. The photovoltaic module of claim 10, wherein the light reflective powder is selected from at least one of calcium carbonate powder, silica powder, and titanium white powder.

12. The photovoltaic module of claim 10, wherein the inorganic binder is a glass powder.

13. A method of manufacturing a photovoltaic module according to any one of claims 1 to 12, comprising: