Bifacial solar cell interconnection structure

Abstract

The present application discloses a double-sided solar cell interconnection structure, including at least two solar panels arranged in one direction, a plurality of grid lines are arranged side by side on the front and back of each solar panel, a plurality of wires are also arranged side by side on the front of each solar panel, the wires intersect with the grid lines and are conductively connected, and the wires have an extension section extending out of the solar panel where they are located; in two adjacent solar panels, the extension section of the wire on one solar panel is electrically connected to the grid line on the back of the other solar panel. The above scheme reduces the internal resistance of the interconnection structure by arranging a plurality of wires, so that the loss caused by the resistance of the interconnection structure can be greatly reduced. In addition, the use of wires can usually reflect the sunlight incident on the wires back to the surface of the solar panel, thereby improving the utilization rate of the light of the solar panel and reducing the adverse effects caused by the shading of the traditional grid line electrode.

Description

Technical Field

[0001] The present invention generally relates to the technical field of solar photovoltaic power generation, and in particular to a double-sided solar cell interconnection structure. Background Art

[0002] At present, with the gradual depletion of fossil energy, solar photovoltaic cells are becoming more and more widely used as a new energy alternative. Solar photovoltaic cells are devices that convert sunlight into electrical energy. Solar photovoltaic cells use the photovoltaic principle to generate carriers, and then use electrodes to lead the carriers out to obtain usable electrical energy.

[0003] The interconnection of solar photovoltaic cells is an important part of photovoltaic solar power generation, and its technical solution has an important impact on the performance of photovoltaic power generation. Shingled structure is a better solution to achieve the interconnection of solar photovoltaic cells. In the shingled structure, the solar photovoltaic cells are overlapped and connected to each other end by end (also called overlap), which greatly reduces the gap in the traditional arrangement and interconnection structure of solar photovoltaic cells. More solar photovoltaic cell units can be set per unit area, which improves the effective utilization of sunlight.

[0004] However, the current solar photovoltaic cell interconnection scheme using a shingled structure has some shortcomings, for example: the internal resistance of the existing shingled solar photovoltaic cell interconnection scheme is too large, affecting the overall power output; due to the limitation of the large transmission resistance of its own interconnection structure, each solar panel (also called solar cell) requires a smaller transmission distance (that is, the solar panel needs to be made narrower). Therefore, if a solar panel using a cutting process is used, the entire panel made of silicon rods needs to be sliced ​​and processed, and cut multiple times to obtain multiple solar panels with narrow widths. The increase in the number of cutting times will lead to a decrease in the yield rate and increase the risk of hidden cracks in the solar panel. In addition, the current solar panels generally form grid electrodes by screen printing silver paste. This method is relatively expensive, and the printed grid electrode has the problem of shading, which has an adverse effect on the photoelectric conversion efficiency. Summary of the invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide a double-sided solar cell interconnection structure, which can at least solve the problems of large internal resistance of the prior interconnection structure, high risk of solar cell panel breakage rate and hidden cracks, high cost of forming grid line electrodes using screen-printed silver paste, and adverse effects on photoelectric conversion efficiency.

[0006] The present invention provides a double-sided solar cell interconnection structure, comprising at least two solar cell panels arranged in one direction, wherein a plurality of grid lines are arranged side by side on the front and back sides of each solar cell panel.

[0007] A plurality of conductive wires are arranged side by side on the front of each solar cell panel, the conductive wires intersect with the grid lines and are conductively connected, and the conductive wires have extension sections extending out of the solar cell panels where they are located;

[0008] In two adjacent solar panels, the extended section of the conductor on one solar panel is electrically connected to the grid line on the back of the other solar panel.

[0009] Furthermore, the solar cell panel is a whole cell panel or a sub-cell panel formed by cutting the whole cell panel into one-half, one-third, one-quarter, one-fifth or one-sixth in a direction parallel to the grid lines.

[0010] Furthermore, adjacent edges of two adjacent solar cell panels are arranged to overlap or be flush with each other.

[0011] Furthermore, at the junction of two adjacent solar panels, the wire is a flat structure.

[0012] Furthermore, a light-transmitting polymer film is laid on the front side of each solar cell panel, and each of the wires is fixedly connected to the polymer film.

[0013] Furthermore, the polymer film includes a base layer and an adhesive layer disposed on the base layer, and the adhesive layer is attached to the front side of the solar cell panel.

[0014] Furthermore, the material of the base layer and / or the bonding layer is at least any one of cellulose acetate, polyolefin, polyamide, polyphenylene ether, fluororesin, polymethyl methacrylate, polysulfone, polyester, epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane and acrylic resin.

[0015] Furthermore, at least a portion of each of the conductive wires is located in the bonding layer.

[0016] Furthermore, a hollow pattern is provided on the polymer film, and the hollow pattern is located between two adjacent conductive wires.

[0017] Furthermore, a conductive layer is provided on the outer peripheral surface of the wire.

[0018] Further, the material of the conductive layer is a metal or alloy with a melting point between 70-180 degrees; or,

[0019] The material of the conductive layer is a conductive resin with a softening temperature between 90 and 120 degrees.

[0020] Further, the material of the conductive layer includes a single substance or alloy of any one of Ag, Bi, Cd, Ga, In, Pb, Sn, Ti, and Zn; or,

[0021] The material of the conductive layer includes a conductive resin, the conductive resin includes a resin substrate and conductive particles arranged in the resin substrate, the resin substrate includes any one of cellulose acetate, fluororesin, polysulfone resin, polyester resin, polyamide resin, polyurethane resin and polyolefin resin, and the conductive particles include at least any one of gold, silver, copper, aluminum, zinc, nickel and graphite.

[0022] Furthermore, adjacent edges of two adjacent solar cell panels are overlapped, and the width of the overlap is 0.1-3 mm.

[0023] Furthermore, the conductive wire is perpendicular to the gate line.

[0024] Furthermore, the thickness of the polymer film is between 5 micrometers and 150 micrometers.

[0025] Furthermore, the number of the wires arranged on the front side of each solar cell panel is 3-100.

[0026] Furthermore, on a straight line, one section of the grid line is arranged or a plurality of sections of the grid line are arranged at intervals.

[0027] Further, the material of the wire includes at least any one of copper, aluminum, silver, gold, copper-nickel alloy and copper-zinc alloy;

[0028] Or the conductor is a copper-clad aluminum wire.

[0029] In the above scheme, the front side of the solar panel connects the grid lines through the wires, and then electrically connects to the grid lines on the back side of the adjacent solar panel. Since the cross-sectional area of ​​the wire is larger than the cross-sectional area of ​​the conventional screen-printed silver-containing grid line electrode under the same width, it is a relatively optimized cross-section, so the maximum effect of current transmission can be achieved. In addition, by setting a plurality of wires, the internal resistance of the interconnection structure is reduced, so that the loss caused by the resistance of the interconnection structure can be greatly reduced. In addition, the use of wires can usually reflect the sunlight incident on the wires to the surface of the solar panel again, thereby improving the utilization rate of the light of the solar panel and reducing the adverse effects caused by the shading of the traditional grid line electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0031] Figure 1 A three-dimensional diagram of a double-sided solar cell interconnection structure provided by an embodiment of the present invention;

[0032] Figure 2 A right side view of a double-sided solar cell interconnection structure provided by an embodiment of the present invention;

[0033] Figure 3 for Figure 1 A partial enlarged view of FIG.

[0034] Figure 4 A three-dimensional diagram of a double-sided solar cell interconnection structure provided by another embodiment of the present invention;

[0035] Figure 5 for Figure 4 A partial enlarged view of H;

[0036] Figure 6 A schematic diagram of combining a wire and a polymer film provided by an embodiment of the present invention;

[0037] Figure 7 A schematic diagram showing a hollowed-out figure provided for an embodiment of the present invention;

[0038] Figure 8 A schematic diagram showing one of the gate line structures provided in an embodiment of the present invention;

[0039] Fig. 9 A schematic diagram showing another gate line structure provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0041] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present 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.

[0042] like Figure 1-Figure 3 As shown, the double-sided solar cell interconnection structure provided by the present invention comprises at least two solar cell panels 1 arranged in one direction, wherein Figure 1 Three solar panels 1 are shown, and a plurality of grid lines 3 are arranged side by side on the front and back of each solar panel 1. The plurality of grid lines 3 are, for example but not limited to, arranged in parallel with uniform intervals. A plurality of wires 2 are also arranged side by side on the front of each solar panel 1. For example but not limited to, the wires 2 are arranged in parallel with uniform intervals. The wires 2 intersect with the grid lines 3 and are conductively connected. The wires have extension sections 9 extending out of the solar panel 1 on which they are located. In two adjacent solar panels 1, the extension section 9 of the wire 2 on one solar panel 1 is electrically connected to the grid line on the back of the other solar panel 1.

[0043] The side-by-side arrangement mentioned herein may be a parallel arrangement or a non-parallel arrangement. For example, but not limited to, a plurality of side-by-side wires may be arranged in a flat shape or in a radial shape.

[0044] The front side refers to the side of the solar cell panel 1 facing the sun when the solar cell panel 1 is working, and the back side refers to the side opposite to the front side.

[0045] The conductor 2 mentioned herein does not only refer to a conductor with a perfect circle cross section, but may also be an ellipse or the like.

[0046] For example but not limited to, the front and back structures of the solar cell panel 1 may be the same.

[0047] In the above scheme, after the grid lines 3 are connected to each other through the wire 2 on the front side of the solar panel 1, they are electrically connected to the grid lines on the back side of the adjacent solar panel 1. Since the cross-sectional area of ​​the wire 2 is larger than the cross-sectional area of ​​the conventional screen-printed silver-containing grid line electrode under the same width, it is a relatively optimized cross-section, so the maximum effect of current transmission can be achieved. In addition, by providing multiple wires 2, the internal resistance of the interconnection structure is reduced, so that the loss caused by the resistance of the interconnection structure can be greatly reduced. In addition, due to the reduction of the internal resistance of the interconnection structure, the solar panel 1 can use a larger unit, and the maximum can be a whole silicon wafer to make a solar panel 1. In addition, the use of the wire 2 can usually reflect the sunlight incident on the wire 2 to the surface of the solar panel 1 again, thereby improving the utilization rate of the light of the solar panel 1 and reducing the adverse effects caused by the shading of the traditional grid line electrode.

[0048] Furthermore, the solar cell panel is a whole cell panel or a sub-cell panel formed by cutting the whole cell panel into one-half, one-third, one-quarter, one-fifth or one-sixth in a direction parallel to the grid line 3 .

[0049] The whole solar panel mentioned in this article is a whole solar panel made of a whole silicon wafer after the silicon rod is sliced.

[0050] Since the internal resistance of the solar panel 1 can be reduced after the wire 2 is arranged on the solar panel 1, the largest solar panel 1 can be a whole panel. Of course, it can also be one-half, one-third, one-quarter, one-fifth or one-sixth of the whole panel. With the interconnection structure, a larger solar panel 1 can be used. In the interconnection structure of the same area, the number of solar panels 1 used is reduced, thereby reducing the number of process connections. At the same time, since a larger solar panel 1 can be used, the number of cutting times for the whole solar panel can be reduced, thereby reducing the risk of mechanical damage, fragmentation rate and hidden cracks caused by cutting.

[0051] Furthermore, the adjacent sides of the two adjacent solar panels 1 can be configured as follows Figure 3 The overlapping structure 4 shown can also be set as Figure 4 , Figure 5 The flush structure shown means that the side surfaces where the adjacent edges of the two adjacent solar cell panels 1 are located are located in the same plane.

[0052] Furthermore, at the junction of two adjacent solar panels 1, the wire 2 is a flat structure. The flat structure is, for example but not limited to, an elliptical, rectangular, or approximately rectangular structure. The use of a flat structure can make it easier for the wire on the surface of the solar panel to form a good contact with the back of the adjacent solar panel. In addition, the gap between the two solar panels 1 can be reduced, and the pressure on the two adjacent solar panels 1 at the wire 2 can also be reduced, thereby reducing the fragmentation rate. It also reduces the generation of bad holes in this interconnection structure in subsequent processes.

[0053] Furthermore, a light-transmitting polymer film is laid on the front side of each solar cell panel 1, and each wire 2 is fixedly connected to the polymer film.

[0054] During production, the wire 2 can be first fixed to a light-transmitting polymer film by heat pressing or the like. In order for the wire 2 to be in full contact with the grid line 3 during the next step of production, a portion of the arc surface of the wire 2 can protrude from the surface of the polymer film. Afterwards, the polymer film with the wire fixed thereon is laid on the front of the solar panel 1, and a portion of the arc surface of the wire 2 protruding from the polymer film is made to face the grid line, and the polymer film is heat pressed to make it adhere to the front of the solar panel 1 to fix each wire 2 and ensure that each wire 2 is electrically connected to the grid line 3. In this way, the laying and alignment of the wire 2 during the production process are more convenient and accurate, and the process complexity is reduced, and even the process steps are reduced, and the wire 2 can be fully electrically connected to the grid line 3.

[0055] Further, see also Figure 6 The polymer film includes a base layer 7 and an adhesive layer 6 disposed on the base layer 7 , and the adhesive layer 6 is attached to the front side of the solar cell panel 1 .

[0056] The polymer film adopts a composite layer structure of an adhesive layer 6 and a base layer 7. During processing, the adhesive layer 6 is attached to the front of the solar panel 1, and it plays the role of an adhesive layer. In addition, the adhesive layer 6 also makes the contact between the wire 2 and the solar panel 1 become a flexible contact, reducing the fragmentation rate. The base layer 7 is cured after hot pressing and has a certain strength, which can protect the structure it covers.

[0057] Furthermore, the material of the base layer and / or the bonding layer is at least any one of cellulose acetate, polyolefin, polyamide, polyphenylene ether, fluororesin, polymethyl methacrylate, polysulfone, polyester, epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane and acrylic resin.

[0058] As a preferred embodiment, the material of the adhesive layer 6 may be at least any one of polyolefin, polyamide, polyphenylene ether, fluororesin, polymethyl methacrylate, polysulfone and polyester.

[0059] As a preferred embodiment, the material of the base layer 7 can be at least any one of epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane and acrylic resin.

[0060] Furthermore, at least a portion of each wire 2 is located in the adhesive layer 6, which can ensure that during the hot pressing process, the wire 2 is pressed to the front side of the solar cell panel 1 and contacts the grid line 3, thereby achieving a good electrical connection.

[0061] Furthermore, if Figure 7 As shown, a hollow pattern 8 is provided on the polymer film, and the hollow pattern 8 is located between two adjacent wires 2. The hollow pattern 8 can be in any shape, such as a rectangle, a circle, an ellipse, etc. The hollow pattern 8 is provided to allow light to directly pass through the hollow pattern 8 to illuminate the front of the solar cell panel, so that the light transmittance is guaranteed, and the amount of polymer film used is reduced, thereby reducing the cost.

[0062] Furthermore, a conductive layer 5 is provided on the outer peripheral surface of the wire 2. The conductive layer 5 acts as an adhesive or solder during the hot pressing process, which is beneficial to achieve a better electrical connection between the wire 2 and the gate line 3 and improves the reliability of the connection.

[0063] Further, the material of the conductive layer 5 is a metal or alloy with a melting point between 70 and 180 degrees; or,

[0064] The conductive layer 5 is made of conductive resin with a softening temperature between 90 and 120 degrees. With the conductive layer 5 having the above temperature, a lower hot pressing temperature can be used, which reduces the thermal stress during hot pressing and prevents the solar cell panel 1 from cracking or breaking.

[0065] Further, the material of the conductive layer 5 includes a single substance or alloy of any one of Ag, Bi, Cd, Ga, In, Pb, Sn, Ti, and Zn. If the melting point of the single substance is higher than this temperature range, the corresponding alloy within this temperature range can be selected; or, the material of the conductive layer 5 includes a conductive resin, the softening temperature of the conductive resin is between 90 and 120 degrees, the conductive resin includes a resin substrate and conductive particles disposed in the resin substrate, the resin substrate includes any one of cellulose acetate, fluororesin, polysulfone resin, polyester resin, polyamide resin, polyurethane resin, and polyolefin resin, and the conductive particles include at least one of gold, silver, copper, aluminum, zinc, nickel, and graphite. The conductive particles may be in the form of granules and / or flakes.

[0066] Furthermore, the adjacent sides of two adjacent solar panels 1 are overlapped, and the width of the overlap 4 is 0.1-3 mm. This width can ensure the contact performance of the connection between the two adjacent solar panels, and will not cause unnecessary loss of the solar panels due to the shielding effect of the overlap. For example, the width of the overlap is set to 0.5 mm, 1.5 mm, 2 mm, 3 mm, etc.

[0067] Furthermore, the wire 2 is perpendicular to the gate line 3, so that the current transmission line is the shortest and the loss is reduced.

[0068] Furthermore, each solar panel is provided with an interconnecting wire (not shown in the figure), and the interconnecting wire is electrically connected to each wire 2 on the solar panel 1 where it is located. As a preferred embodiment, the interconnecting wire is perpendicular to the wire 2.

[0069] By arranging interconnecting wires between the wires 2, the performance of power transmission caused by poor electrode contact areas and poor connection between solar panels can be guaranteed, thereby improving the yield rate. The wire diameter of the interconnecting wire can be the same as or different from that of the wire 2. One interconnecting wire can be arranged, or multiple interconnecting wires can be arranged at appropriate intervals. The number of interconnecting wires to be arranged should be comprehensively considered to ensure the transmission of current and to ensure as little shading as possible.

[0070] Furthermore, the thickness of the polymer film may be between 5 micrometers and 150 micrometers, so as to ensure that the polymer film has sufficient stability under heat pressing, and that the surface of the polymer film shrinks little and is flat after cooling.

[0071] Furthermore, the number of the wires 2 arranged on the front side of each solar cell panel 1 is 3 to 100. The wires 2 may be arranged at even intervals.

[0072] The number of settings can be determined by comprehensively considering ensuring the transmission of current and minimizing shading.

[0073] Furthermore, on a straight line, a segment of grid line is arranged or a plurality of segments of grid lines are arranged at intervals.

[0074] like Figure 8 As shown, a grid line 3 is arranged on a straight line.

[0075] like Fig. 9 As shown, multiple segments of grid lines 3 are arranged at intervals on a straight line. Each segment of grid line 3 is connected to a wire. The use of multiple segments of grid lines 3 can save materials for processing the grid lines 3, further reduce shading, increase the effective light absorption area of ​​the solar cell panel, and thus improve the photoelectric conversion efficiency.

[0076] Furthermore, the material of the conductor 2 can be selected from at least one of copper, aluminum, silver, gold, copper-nickel alloy and copper-zinc alloy. The conductor 2 can also be made of a composite layer structure wire such as copper-clad aluminum wire. As a preferred embodiment, the conductor 2 is made of copper wire, which has a high electrical conductivity and a low cost compared to precious metals such as gold and silver.

[0077] The conductive layer 5 is formed on the outer surface of the conductive wire 2 by, for example, but not limited to, coating or other processes. The wire diameter of the conductive wire 2 is, for example, but not limited to, 50 um, 100 um, 150 um, and the like.

[0078] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

Claims

1. A double-sided solar cell interconnection structure, comprising at least two solar cell panels arranged in one direction, wherein a plurality of grid lines are arranged side by side on the front and back sides of each solar cell panel, characterized in that: A plurality of conductive wires are arranged side by side on the front of each solar cell panel, the conductive wires intersect with the grid lines and are conductively connected, and the conductive wires have extension sections extending out of the solar cell panels where they are located; In two adjacent solar panels, an extension section of a wire on one solar panel is electrically connected to a grid line on the back of another solar panel, the middle of each wire is a flat structure, the wires at both ends of the flat structure are perfect circular structures, and the flat structure is located at the junction of the two adjacent solar panels, the two adjacent solar panels are overlapped at the junction, one perfect circular structure is located on the front of one of the two adjacent solar panels, and the other perfect circular structure is located on the back of the other of the two adjacent solar panels, the outer peripheral surface of the wire is provided with a conductive layer, the material of the conductive layer is a metal or alloy with a melting point between 70 and 180 degrees, and the wire is welded to the grid line through the conductive layer; The front of each solar cell panel is paved with a light-transmitting polymer film, and each of the wires is fixedly connected to the polymer film; The polymer film includes a base layer and an adhesive layer disposed on the base layer, and the adhesive layer is attached to the front side of the solar cell panel; The polymer film is provided with a hollow pattern, and the hollow pattern is located between two adjacent conductive wires.

2. The double-sided solar cell interconnection structure according to claim 1, characterized in that: The solar cell panel is a whole cell panel or a sub-cell panel formed by cutting the whole cell panel into one-half, one-third, one-quarter, one-fifth or one-sixth in a direction parallel to the grid lines.

3. The double-sided solar cell interconnection structure according to claim 1, characterized in that: Adjacent edges of two adjacent solar cell panels are arranged to overlap or be flush with each other.

4. The double-sided solar cell interconnection structure according to claim 1, characterized in that: The material of the base layer and / or the adhesive layer is at least any one of cellulose acetate, polyolefin, polyamide, polyphenylene ether, fluororesin, polymethyl methacrylate, polysulfone, polyester, epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane and acrylic resin.

5. The double-sided solar cell interconnection structure according to claim 1, characterized in that: At least a portion of each of the conductive lines is located in the bonding layer.

6. The double-sided solar cell interconnection structure according to claim 1, characterized in that: The material of the conductive layer includes a single substance or an alloy of any one of Ag, Bi, Cd, Ga, In, Pb, Sn, Ti, and Zn.

7. The double-sided solar cell interconnection structure according to any one of claims 1 to 4, characterized in that: The adjacent edges of two adjacent solar cell panels are overlapped, and the width of the overlap is 0.1-3 mm.

8. The double-sided solar cell interconnection structure according to any one of claims 1 to 4, characterized in that: The conductive wire is perpendicular to the gate line.

9. The double-sided solar cell interconnection structure according to claim 1, characterized in that: The polymer film has a thickness between 5 micrometers and 150 micrometers.

10. The double-sided solar cell interconnection structure according to any one of claims 1 to 4, characterized in that: The number of the wires arranged on the front side of each solar cell panel is 3-100.

11. The double-sided solar cell interconnection structure according to any one of claims 1 to 4, characterized in that: On a straight line, one segment of the grid line is arranged or a plurality of segments of the grid line are arranged at intervals.

12. The double-sided solar cell interconnection structure according to any one of claims 1 to 4, characterized in that: The material of the wire includes at least any one of copper, aluminum, silver, gold, copper-nickel alloy and copper-zinc alloy; Or the conductor is a copper-clad aluminum wire.

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