Back contact solar cell module

Abstract

The invention discloses a back contact solar cell module, which comprises a plurality of back contact solar cells arranged along a first direction and a solder strip extending along the first direction and interconnecting the back contact solar cells, and is characterized in that the back surface of each back contact solar cell is provided with a plurality of groups of bonding pads arranged at intervals along a second direction; each group of bonding pads comprises a plurality of bonding pads which are arranged at intervals along the first direction, the first direction is perpendicular to the second direction, and the welding strips for connecting the adjacent back contact solar cells in series are respectively connected with the bonding pads which are closest to each other of the adjacent back contact solar cells; an isolating layer is arranged between the part of the welding strip between the pair of bonding pads closest to each other and the pair of adjacent back contact solar cells, and the isolating layer continuously extends from the bonding pads closest to each other to the adjacent edges of the pair of back contact solar cells along the first direction. Due to the blocking of the isolating layer, no physical connection is formed between the part of the welding strip and the electrode below the isolating layer, and the risk that the electrode at the edge of the back contact solar cell is pulled out of the grid by the welding strip is reduced.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to a back-contact solar cell module. Background Art

[0002] The positive and negative electrodes of a back-contact solar cell are both located on the side facing away from the light. This leaves the light-receiving side unobstructed, increasing the optical absorption of the solar cell. Multiple back-contact solar cells are interconnected to form a back-contact solar cell string, which can then be packaged into a back-contact solar cell module.

[0003] In the related art, back-contact solar cells are generally connected in series using soldering ribbons, and there is a high risk that the main grid near the edge pad of the cell will be pulled off by the soldering ribbons. Summary of the Invention

[0004] The present invention provides a back-contact solar cell module, which reduces the risk of a main grid near a cell edge pad being pulled off by a welding ribbon.

[0005] The back-contact solar cell module of the present invention includes a plurality of back-contact solar cells arranged along a first direction and a welding ribbon extending along the first direction and interconnecting the back-contact solar cells. The back of the back-contact solar cell has a plurality of groups of welding pads spaced apart along a second direction. Each group of welding pads has a plurality of welding pads spaced apart along the first direction. The first direction and the second direction are perpendicular to each other. The welding ribbons connecting adjacent back-contact solar cells in series are respectively connected to the welding pads of the adjacent back-contact solar cells that are closest to each other. An isolation layer is provided between the portion of the welding ribbon located between the pair of welding pads closest to each other and the pair of adjacent back-contact solar cells. The isolation layer extends continuously along the first direction from the welding pads closest to each other to the adjacent edges of the pair of back-contact solar cells.

[0006] In some embodiments, along the extension path of the isolation layer, all electrodes between the pads of the adjacent back-contact solar cells closest to each other and the edges of the pair of back-contact solar cells adjacent to each other are covered by the isolation layer.

[0007] In some embodiments, the isolation layer has a center line of the pair of pads closest to each other along the first direction as a center line, and a minimum width of the isolation layer in the second direction is 1.5-2.5 mm.

[0008] In some embodiments, a back-contact solar cell includes a first bus electrode and a second bus electrode having different conductivity types, the first bus electrode and the second bus electrode being formed on the back side of the back-contact solar cell, the first bus electrode and the second bus electrode extending parallel to each other in a first direction and alternately arranged in a second direction.

[0009] In some embodiments, the back-contact solar cell further includes a first finger electrode of the same conductive type as and connected to the first bus electrode and a second finger electrode of the same conductive type as and connected to the second bus electrode, the first finger electrodes extending parallel to each other along the second direction between adjacent first bus electrodes and second bus electrodes and arranged at intervals in the first direction, the ends of the first finger electrodes are spaced apart from the second bus electrodes, the second finger electrodes extending parallel to each other along the second direction between adjacent first bus electrodes and second bus electrodes and arranged at intervals in the first direction, the ends of the first finger electrodes are spaced apart from the second bus electrodes, and the first finger electrodes and the second finger electrodes between adjacent first bus electrodes and second bus electrodes are alternately arranged in the first direction.

[0010] In some embodiments, each first bus electrode and each second bus electrode are respectively connected to a plurality of pads arranged at intervals in the first direction.

[0011] In some embodiments, a width of the pad in the second direction is greater than a width of the first bus electrode and the second bus electrode.

[0012] In some embodiments, the solder pad near the edge of the back-contact solar cell is farther away from the edge than the first bus electrode and / or the second bus electrode near the edge of the back-contact solar cell, and the solder pad near the edge is conductively connected to the first bus electrode and / or the second bus electrode near the edge through the connecting electrode.

[0013] Along the extension path of the isolation layer, all electrodes between the end pads and the edge of the back-contact solar cell are covered by the isolation layer. When the back-contact solar cells are interconnected using a soldering ribbon, the isolation layer blocks the connection, preventing a physical connection between portions of the soldering ribbon and the electrodes beneath the isolation layer. This reduces the risk of portions of the soldering ribbon pulling electrodes at the edge of the back-contact solar cell off the grid when adjacent back-contact solar cells undergo relative movement that deviates from the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A back view of a cell string of a back-contact solar cell module according to an example embodiment of the present disclosure is shown.

[0016] Figure 2A back view of a back-contact solar cell according to an example embodiment of the present disclosure is shown.

[0017] Figure 3 A diagram illustrating an arrangement of back-contact solar cells in a back-contact solar cell string according to an example embodiment of the present disclosure is shown.

[0018] Figure 4 Shown Figure 1 A partial enlarged view of position A in FIG.

[0019] Figure 5 Shown Figure 1 A partial enlarged view of position B in FIG.

[0020] Figure 6 Shown Figure 1 A partial enlarged view of the C position in FIG. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] The inventors of this disclosure discovered that the inevitable relative movement between cells during the transfer process of a solar cell string can cause the solder ribbons connecting the solar cells in series to pull on the grid lines at the edges of the pads, causing the grid lines to become detached. The solder ribbons of a back-contact solar cell string are all located on the back of the back-contact solar cells. The inconsistent vertical jitter of adjacent back-contact solar cells further increases the risk of grid lines becoming detached at the edges of the pads. Attempts have been made to improve the adhesion between the grid lines of back-contact solar cells and the semiconductor silicon substrate to address this issue.

[0024] In view of the problems of the prior art, the inventors of the present disclosure propose a new solution.

[0025] Figure 1 1 shows a cell string of a back-contact solar cell module according to an example embodiment of the present disclosure. More specifically, Figure 1 A back-contact solar cell string including three adjacent back-contact solar cells 10 is shown. The three adjacent back-contact solar cells 10 have a rectangular thin plate shape, are arranged substantially on the same plane, are aligned along a first direction D1, and are connected to each other. Figure 2 Shown Figure 1 A back view of a back-contact solar cell of a back-contact solar cell string according to an example embodiment of the present invention. Figure 3 Shown Figure 1 Shown is a rear view of a back-contact solar cell string without being interconnected.

[0026] like Figure 1 As shown, the back-contact photovoltaic module includes a plurality of back-contact solar cells 10 arranged along a first direction D1 and a solder ribbon 20 extending along the first direction D1 and connecting the back-contact solar cells 10 in series.

[0027] like Figure 2 As shown, the back-contact solar cell 10 includes a first bus electrode 11 and a second bus electrode 12 having different conductivity types. The first bus electrode 11 and the second bus electrode 12 are formed on the back side of the back-contact solar cell 10 to collect and transport electrons and holes, respectively.

[0028] The first bus electrodes 11 and the second bus electrodes 12 extend parallel to each other in a first direction D1 and are alternately arranged in a second direction D2, wherein the first direction D1 and the second direction D2 are two directions perpendicular to each other. Figure 2 As shown, the first bus electrodes 11 extend parallel to each other along the first direction D1 and are spaced apart in the second direction D2. The second bus electrodes 12 extend parallel to each other along the first direction D1 and are spaced apart in the second direction D2. The first bus electrodes 11 and the second bus electrodes 12 are alternately arranged in the second direction D2 and are spaced apart from each other by a uniform or substantially uniform distance.

[0029] Please continue to refer to Figure 2 The back-contact solar cell 10 further includes first finger electrodes 13 of the same conductivity type as the first bus electrodes 11 and second finger electrodes 14 of the same conductivity type as the second bus electrodes 12. The first finger electrodes 13 and the second finger electrodes 14 are formed on the back side of the back-contact solar cell 10, connected to the first bus electrodes 11 and the second bus electrodes 12, respectively, to collect electrons and holes. The first finger electrodes 13 extend parallel to each other along the second direction D2 between adjacent first bus electrodes 11 and second bus electrodes 12, and are arranged at intervals in the first direction D1. The ends of the first finger electrodes 13 are spaced apart from the second bus electrodes 12. The second finger electrodes 14 extend parallel to each other along the second direction D2 between adjacent first bus electrodes 11 and second bus electrodes 12, and are arranged at intervals in the first direction D1. The ends of the first finger electrodes 13 are spaced apart from the second bus electrodes 12. The first finger electrodes 13 and the second finger electrodes 14 between adjacent first bus electrodes 11 and second bus electrodes 12 are alternately arranged in the first direction D1 and are spaced apart by a uniform distance.

[0030] The back side of the back-contact solar cell also has multiple groups of solder pads spaced apart in the second direction D2. Each group of solder pads includes multiple solder pads 15 spaced apart in the first direction D1. Specifically, each first bus electrode 11 and each second bus electrode 12 is connected to the multiple solder pads 15 spaced apart in the first direction D1. The width of the solder pads 15 in the second direction D2 is greater than the width of the first bus electrode 11 and the second bus electrode 12. More specifically, the solder pads 15 include a first solder pad 151 conductively connected to the first bus electrode 11 and a second solder pad 152 conductively connected to the second bus electrode 12.

[0031] In some examples, the pad 15 is formed as a portion of the first bus electrode 11 and the second bus electrode 12 .

[0032] In some examples, the solder pads 15 of a local area of ​​the back-contact solar cell 10 are allowed to be separated from the bus electrodes. For example, at the edge of the back-contact solar cell 10, the solder pads 15 are physically separated from the first bus electrode 11 and / or the second bus electrode 12 near the edge of the solar cell. The solder pads 15 are farther away from the edge to which the first bus electrode 11 and / or the second bus electrode 12 are close relative to the first bus electrode 11 and / or the second bus electrode 12, and the solder pads 15 are conductively connected to the first bus electrode 11 and / or the second bus electrode 12 at the edge through the connecting electrode 16. The solder ribbon 20 is physically and conductively connected to the solder pads 15, separating the bus electrodes at the edge from the solder pads 15, thereby reducing the risk of hidden cracks at the edge of the cell caused by welding the solder ribbon 20 at the edge of the back-contact cell. The current of the first bus electrode 11 and / or the second bus electrode 12 at the edge is transmitted to the solder pads 15 and the solder ribbon 20 through the connecting electrode 16.

[0033] The back-contact solar cells 10 are arranged along a first direction D1. The first and second bus electrodes 11, 12 extend along the first direction D1. The first and second bus electrodes 11, 12 of adjacent back-contact solar cells are aligned. More specifically, the first and second soldering pads 151, 152 of adjacent back-contact solar cells are aligned. For example, the first soldering pad 151 of the second back-contact solar cell 10b is aligned with the second soldering pads 152 of the adjacent first and third back-contact solar cells 10a, 10c. The second soldering pad 152 of the second back-contact solar cell 10b is aligned with the first soldering pads 151 of the adjacent first and third back-contact solar cells 10a, 10c.

[0034] Please refer to Figure 1The first soldering pad 151 and the second soldering pad 152 are respectively connected to the soldering ribbon 20, and then connected to the second soldering pad 152 and the first soldering pad 151 of another back contact solar cell 10 adjacent to the back contact solar cell 10. The soldering ribbon 20 is configured to connect multiple back contact solar cells in series. Figure 1 As shown, a cell string consisting of three back-contact solar cells 10 is taken as an example.

[0035] Figure 1 The back-contact solar cell string shown includes a first back-contact solar cell 10 a , a second back-contact solar cell 10 b , and a third back-contact solar cell 10 c , which are sequentially arranged in a first direction D1 .

[0036] Taking the middle second back-contact solar cell 10b as an example, the soldering ribbon 20 includes a first soldering ribbon 21 and a second soldering ribbon 22, both extending along the first direction D1. One side of the first soldering ribbon 21 is conductively connected to the first soldering pad 151 of the second back-contact solar cell 10b, and the other side is conductively connected to the second soldering pad 152 of the first back-contact solar cell 10a. One side of the second soldering ribbon 22 is conductively connected to the second soldering pad 152 of the second back-contact solar cell 10b, and the other side is conductively connected to the first soldering pad 151 of the third back-contact solar cell 10c. This connects the first, second, and third back-contact solar cells 10a, 10b, and 10c in series.

[0037] More specifically, the first soldering ribbon 21 is conductively connected to the first soldering pads 151 of the second back-contact solar cell 10b, which are arranged along the first direction D1. The ribbon extends along the first direction D1 to the adjacent first back-contact solar cell 10a and is conductively connected to the second soldering pad 152 of the first back-contact solar cell 10a, thereby connecting the second back-contact solar cell 10b and the first back-contact solar cell 10a in series. The second soldering ribbon 22 is conductively connected to the second soldering pads 152 of the second back-contact solar cell 10b, which are arranged along the first direction D1. The ribbon extends along the first direction D1 to the adjacent third back-contact solar cell 10c and is conductively connected to the second soldering pad 152 of the third back-contact solar cell 10c.

[0038] Figure 4 Shown Figure 1 The enlarged view of the back contact solar cell string at position A is shown. Figure 1The portions of the opposite-conductivity finger electrodes near the bus electrodes and the solder ribbon 20 are partially covered with an insulating layer 30 to prevent the solder ribbon 20 of the opposite conductivity type from contacting the finger electrodes and causing a short circuit. For example, the ends of the second finger electrodes 14 near the first bus electrode 11 and the first solder pad 151 are covered with the insulating layer 30, and the ends of the first finger electrodes 13 near the second bus electrode 12 and the second solder pad 152 are also covered with the insulating layer 30. The solder ribbon 20 connected to the solder pad 15 physically separated from the edge of the first bus electrode 11 and / or the second bus electrode 12 is also covered by the insulating layer 30 between the solder ribbon 20 and the opposite-conductivity electrode below. The insulating layer 30 can be an electrically insulating material primarily composed of one or more of epoxy resin, silicone resin, polyurethane, or acrylic resin.

[0039] In some examples, the solder ribbons 20 connecting adjacent back-contact solar cells in series are respectively connected to the solder pads 15 of the adjacent back-contact solar cells 10 that are closest to each other. An isolation layer 40 is provided between a portion 23 of the solder ribbon 20 located between the pair of solder pads 15 that are closest to each other and the pair of adjacent back-contact solar cells 10. The isolation layer 40 extends continuously along a first direction D1 from the solder pads 15 to the adjacent edges of the pair of back-contact solar cells 10. The isolation layer 40 can be made of the same material as the insulating layer 30.

[0040] Figure 5 Shown Figure 1 A partial enlarged view of the positions of adjacent edges B of adjacent back-contact solar cells in an exemplary embodiment is shown. More specifically, continuing with the example of the second back-contact solar cell 10b, the second back-contact solar cell 10b has a first edge e1 adjacent to the first back-contact solar cell 10a, and the first back-contact solar cell 10a has a second edge e2 adjacent to the second back-contact solar cell 10b. A first solder ribbon 21 spans the first edge e1 and the second edge e2. The first solder pads 151 disposed on the back side of the second back-contact solar cell 10b include a first end solder pad 151a closest to the first edge e1, and the second solder pads 152 disposed on the back side of the first back-contact solar cell 10a include a second end solder pad 152a closest to the second edge e2. The back side of the second back-contact solar cell 10b has an isolation layer 40 extending from the first end solder pad 151a to the first edge e1, while the back side of the first back-contact solar cell 10a has an isolation layer 40 extending from the second end solder pad 152a to the second edge e2.

[0041] Figure 6 Shown Figure 1A partial enlarged view of the positions of adjacent edges C of adjacent back-contact solar cells in the illustrated exemplary embodiment. The second back-contact solar cell 10b has a second edge e2 adjacent to the third back-contact solar cell 10c, and the third back-contact solar cell 10c has a first edge e1 adjacent to the second back-contact solar cell 10b. A second solder ribbon 22 spans the second edge e2 and the first edge e1. The second solder pads 152 disposed on the back side of the second back-contact solar cell 10b include a second end solder pad 152a closest to the second edge e2, while the first solder pads 151 disposed on the back side of the third back-contact solar cell 10c include a first end solder pad 151a closest to the first edge e1. The back side of the second back-contact solar cell 10b has an isolation layer 40 extending from the second end solder pad 152a to the second edge e2, while the back side of the third back-contact solar cell 10c has an isolation layer 40 extending from the first end solder pad 151a to the first edge e1.

[0042] Along the extension path of the isolation layer 40, all electrodes between the end pad 15 and the edge of the back-contact solar cell are covered by the isolation layer 40. For example, bus electrodes, finger electrodes of the same and opposite sexes. When the back-contact solar cells are interconnected using the soldering ribbon 20 by welding, due to the obstruction of the isolation layer 40, no physical connection is formed between the portion 23 of the soldering ribbon 20 and the electrode below the isolation layer 40. When adjacent back-contact solar cells produce relative movement that deviates from the first direction D1, the risk of the portion 23 of the soldering ribbon 20 pulling the electrode at the edge of the back-contact solar cell off the grid is reduced.

[0043] In an exemplary embodiment of the present disclosure, the isolation layer 40 is centered about the center line of the pad 15 along the first direction D1, and the minimum width W of the isolation layer 40 in the second direction D2 is 1.5-2.5 mm. The center line of the pad 15 along the first direction D1 is a virtual line passing through the center of the pad 15 and parallel to the first direction D1. With the center line of the pad 15 along the first direction D1 as a reference, the minimum distance W / 2 from both sides of the isolation layer 40 to the center line of the pad 15 along the first direction D1 is 0.75-1.25 mm. The isolation layer 40 has a certain width, which can both prevent the portion 23 of the solder ribbon 20 from being physically connected to the gate line and reduce the alignment requirements of the solder ribbon 20.

[0044] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A back contact solar cell module, characterized in that: The invention comprises a plurality of back-contact solar cells arranged along a first direction and a welding ribbon extending along the first direction and interconnecting the back-contact solar cells, the back side of the back-contact solar cells having a plurality of groups of welding pads spaced apart along a second direction, each group of welding pads having a plurality of welding pads spaced apart along the first direction, the first direction and the second direction being perpendicular to each other, the welding ribbons connecting adjacent back-contact solar cells in series are respectively connected to the welding pads of the adjacent back-contact solar cells that are closest to each other, an isolation layer is provided between the portion of the welding ribbon located between the pair of welding pads that are closest to each other and the pair of adjacent back-contact solar cells, the isolation layer continuously extending along the first direction from the welding pads that are closest to each other to the adjacent edges of the pair of back-contact solar cells.

2. The back contact solar cell according to claim 1, characterized in that Along the extension path of the isolation layer, all electrodes between the soldering pads of the adjacent back-contact solar cells closest to each other and the edges of the pair of back-contact solar cells adjacent to each other are covered by the isolation layer.

3. The back contact solar cell according to claim 1, characterized in that The isolation layer has a center line of the pair of pads closest to each other along the first direction as a center line, and a minimum width of the isolation layer in the second direction is 1.5-2.5 mm.

4. The back contact solar cell according to claim 1, characterized in that The back-contact solar cell includes a first bus electrode and a second bus electrode of different conductivity types, the first bus electrode and the second bus electrode are formed on the back side of the back-contact solar cell, the first bus electrode and the second bus electrode extend parallel to each other in the first direction and are alternately arranged in the second direction.

5. The back contact solar cell according to claim 4, characterized in that: The back contact solar cell further includes a first finger electrode of the same conductivity type as the first bus electrode and connected thereto, and a second finger electrode of the same conductivity type as the second bus electrode and connected thereto. The first finger electrodes extend parallel to each other along the second direction between adjacent first bus electrodes and second bus electrodes and are arranged at intervals in the first direction, and ends of the first finger electrodes are spaced apart from the second bus electrodes. The second finger electrodes extend parallel to each other along the second direction between adjacent first bus electrodes and second bus electrodes and are arranged at intervals in the first direction, and ends of the first finger electrodes are spaced apart from the second bus electrodes. The first finger electrodes and the second finger electrodes between adjacent first bus electrodes and second bus electrodes are alternately arranged in the first direction.

6. The back contact solar cell according to claim 4, characterized in that: Each of the first bus electrodes and each of the second bus electrodes are respectively conductively connected to a plurality of pads arranged at intervals in the first direction.

7. The back contact solar cell according to claim 4, characterized in that: A width of the pad in the second direction is greater than widths of the first bus electrode and the second bus electrode.

8. The back contact solar cell according to claim 4, characterized in that: The soldering pad near the edge of the back-contact solar cell is farther away from the edge than the first bus electrode and / or the second bus electrode near the edge of the back-contact solar cell, and the soldering pad near the edge is conductively connected to the first bus electrode and / or the second bus electrode near the edge through a connecting electrode.

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