Thin film solar cell string assembly and preparation method thereof

Abstract

The invention provides a thin film solar cell string assembly and a preparation method thereof, and belongs to the technical field of solar cells. The module comprises a flexible base film, a plurality of solar cell pieces connected in series and a fixing strip, the plurality of solar cells are arranged on the flexible base film along a first direction; a fixing strip is arranged above the solar cell, and the fixing strip is adhered to the flexible base film along two ends perpendicular to the first direction. The preparation difficulty of the solar cell string assembly is reduced, the flatness of the solar cell string assembly is easier to control, the gravimetric specific power of the thin film solar cell string assembly is remarkably improved, and the thin film solar cell string assembly is more suitable for application scenes with lightweight and efficient power generation requirements.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and in particular relates to a thin-film solar cell string assembly and its preparation method. Background Technology

[0002] Thin-film solar cells possess characteristics such as high specific power and shapeability, allowing them to be attached to surfaces like airfoils and buildings to provide energy for aircraft and structures. The manufacturing process for thin-film solar cell modules involves first connecting several thin-film solar cells to form a solar cell string module, and then encapsulating the solar cell strings to form the solar cell module. Traditional solar cell string bonding processes require adhering solar cells to a base film, which is not only cumbersome and difficult to control in terms of flatness, but also results in a lower power-to-weight ratio in the formed solar cell string module. This, in turn, affects the power-to-weight ratio of the solar cell module, making it difficult to meet the requirements of lightweight and high-efficiency power generation applications. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a thin-film solar cell string assembly and its fabrication method, which reduces the fabrication difficulty of the thin-film solar cell string assembly, makes it easier to control the flatness of the solar cell string assembly, and significantly improves the power-to-weight ratio of the solar cell string.

[0004] The technical solution adopted in this invention is: a thin-film solar cell string assembly, including a flexible base film, multiple solar cells connected in series and a fixing strip; the solar cells are disposed on the flexible base film along a first direction; a fixing strip is provided above the solar cells, and the fixing strip is bonded to the flexible base film at both ends perpendicular to the first direction.

[0005] Furthermore, the ends of adjacent solar cells that are close to each other are connected by an interconnecting strip; the fixing strip extends from the connection end of one solar cell to the connection end of the adjacent solar cell to the interconnecting strip, or covers the edge of the solar cell located at the edge.

[0006] Furthermore, the fixing strip on the solar cell located at the edge protrudes from the adjacent edge.

[0007] Furthermore, the electrodes of the solar cell are located on the front and back sides of the solar cell, respectively; the electrodes are provided with solder joints, and the two ends of the interconnect are welded to the solder joints to form a welded part.

[0008] Furthermore, the fixing strip covers the welded portion on the front side of the solar cell and / or the front area corresponding to the welded portion on the back side of the solar cell.

[0009] Furthermore, the fixing strip is a transparent insulating film with a transmittance of more than 90% at 600nm.

[0010] Furthermore, the areal density of the solar cell is no greater than 220 g / m². 2 The photoelectric conversion efficiency is not less than 32%.

[0011] Furthermore, the flexible base film is a PET, PVC or PE film with a thickness of no more than 100 micrometers and an areal density of no more than 100 g / m2.

[0012] Furthermore, the interconnect sheet is aluminum foil or silver foil with a thickness of no more than 100 micrometers.

[0013] A method for fabricating a thin-film solar cell string module includes the following steps:

[0014] Place the flexible base film on a flat surface;

[0015] The solar cells are placed sequentially on the flexible base film;

[0016] The adjacent solar cells are connected by interconnecting sheets;

[0017] The fixing strip is placed above the connection end of the adjacent solar cells and above the edge end of the solar cells located at the edge;

[0018] The two ends of the fixing strip are bonded to the flexible base film.

[0019] The advantages and positive effects of this invention are:

[0020] (1) The present invention uses a fixing strip to press the solar cell onto the flexible base film, and then the two ends of the fixing strip are bonded to the flexible base film. Compared with the traditional method of bonding the solar cell to the flexible base film, the manufacturing difficulty is reduced and the flatness of the solar cell string assembly is easier to control.

[0021] (2) By refining the connection structure and materials of flexible base film, interconnect sheet, solar cell and fixing strip, the solar cell string has a higher power-to-weight ratio, which is conducive to improving the power-to-weight ratio of thin film solar cell module and is more suitable for application scenarios with lightweight and high-efficiency power generation requirements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the component structure of a specific embodiment of the present invention;

[0023] Figure 2 This is a top view of a component according to a specific embodiment of the present invention.

[0024] In the picture:

[0025] 1. Solar cell; 2. Flexible base film; 3. Interconnect sheet; 4. Fixing strip. Detailed Implementation

[0026] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] This invention provides a thin-film solar cell string assembly, including a flexible base film 2, multiple solar cells 1 connected in series, and a fixing strip 4; the multiple solar cells 1 are disposed on the flexible base film 2 along a first direction; the fixing strip 4 is provided above the solar cells 1, and the fixing strip 4 is bonded to the flexible base film 2 at both ends perpendicular to the first direction. The aforementioned flexible base film 2 is used to support the solar cell 1, and the flexible base film 2 is in contact with the solar cell 1. The solar cells 1 are arranged at equal intervals along the first direction, and each solar cell 1 is pressed against the flexible base film 2 by a fixing strip 4. The two ends of the fixing strip 4 are bonded to the flexible base film 2, together forming a solar cell string assembly. With this arrangement, compared with the traditional method of bonding the solar cell 1 to the flexible base film 2, the bonding area is reduced, the bonding operation difficulty is reduced, and deformation and wrinkling of the flexible base film 2 can be avoided when bonding the solar cell 1. At the same time, it is easier to control the flatness of the solar cell string assembly. More importantly, this arrangement reduces the amount of adhesive used, so that the solar cell string has a higher power-to-weight ratio, which is conducive to improving the power-to-weight ratio of thin-film solar cell modules and improving their applicability to application scenarios with lightweight and high-efficiency power generation requirements.

[0028] In one specific embodiment, the flexible base film 2 is a strip-shaped film with its length direction being the first direction. The solar cells 1 are arranged at equal intervals along its length direction and are located in the middle of the width direction of the flexible base film 2. The solar cells 1 include a long side and a short side, with the long side direction being perpendicular to the first direction. The length direction of the fixing strip 4 is also perpendicular to the first direction. That is, the long side of the solar cell and the fixing strip 4 are both arranged along the width direction of the flexible base film 2, and the two ends of the fixing strip 4 are bonded between the short side of the solar cell and the edge of the flexible base film 2.

[0029] Furthermore, in this embodiment, adjacent solar cells 1 are connected at their close ends by interconnecting sheets 3; fixing strips 4 extend from the connection end of one solar cell 1 and the interconnecting sheet 3 to the connection end of adjacent solar cells 1 and the interconnecting sheet 3, or cover the edge end of the solar cell 1 located at the edge. Specifically, each solar cell 1 has an electrode at its close ends, and the two ends of the interconnecting sheet 3 are respectively welded to the electrodes of two adjacent solar cells 1; the coverage area of ​​the fixing strip 4 located in the middle includes the connection end of the interconnecting sheets 3 of two adjacent solar cells, the interconnecting sheet 3, and the gap between the two adjacent solar cells 1; at the same time, the end of the solar cell 1 located at the edge of the flexible base film 2 along its length direction is the edge end, and the edge end is also provided with an interconnecting sheet 3 for leading out, and the fixing strip 4 at this position covers the edge end. This design allows one fixing strip 4 to simultaneously fix two adjacent solar cells 1, with both ends of the solar cell 1 being pressed down by the fixing strip 4, resulting in higher stability. At the same time, the connection points between the solar cell 1 and the interconnecting sheet 3, as well as the interconnecting sheet 3, are the weak points of the solar cell string. By covering them with the fixing strip 4, a good protective effect can be formed, effectively preventing the connection points or the interconnecting sheet 3 from being damaged or moved.

[0030] In the above embodiment, the fixing strip 4 on the solar cell 1 located at the edge protrudes from the edge end and extends at least partially to the outside of the edge end, thus forming a stable fixation and good protection for the solar cell 1.

[0031] In the above embodiments, the connecting end and the adjacent end are both continuous planes where the long side of the solar cell is located, and part of the fixing strip 4 covers the entire length range of the connecting end or the adjacent end.

[0032] In one specific embodiment, the electrodes of the solar cell 1 are located on the front and back sides of the solar cell 1, respectively; the electrodes are provided with solder joints, and the two ends of the interconnecting piece 3 are soldered to the solder joints, forming a welded portion. The back side of the solar cell is in contact with the flexible base film 2, and the front side is in contact with the fixing strip 4; one end of the interconnecting piece 3 is soldered to the welded portion on the front side of one solar cell 1, and extends from this welded portion to the back side of another adjacent solar cell 1, where it is soldered to the welded portion on the back side of the other adjacent solar cell 1. The welded portion may include one or more solder joints, and the length of the welded portion is set to the long side direction of the solar cell 1. The width of the interconnecting piece 3 is preferably not less than the length of the welded portion.

[0033] Furthermore, the fixing strip 4 covers the welded portion on the front side of the solar cell 1 and / or the area corresponding to the welded portion on the back side of the solar cell 1. Specifically, the fixing strip 4 located on the solar cell 1 in the middle of the flexible base film 2 covers the entire width and length of the welded portion on the front side of one solar cell 1, as well as the area on the front side of an adjacent solar cell 1 corresponding to the entire width and length of the welded portion on its back side. That is, along the first direction, the length of the fixing strip 4 is sufficient to cover at least the welded portion on the front side of one solar cell 1, the gap between solar cells 1, the interconnecting sheet 3, and the front area corresponding to the welded portion on the back side of an adjacent solar cell. The fixing strip 4 located at the edge of the solar cell 1 near the edge of the flexible base film 2 covers the front area corresponding to either the welded portion on the front side or the welded portion on the back side of that solar cell 1, and extends to the outer part of the solar cell 1. This arrangement further ensures the fixing and protection function of the fixing strip 4 for the solar cell 1.

[0034] In one specific embodiment, the length of the interconnecting piece 3 is 5 to 15 mm; the width of the fixing strip 4 is 2 to 5 mm.

[0035] Furthermore, in this embodiment, the fixing strip 4 is a transparent insulating film with a transmittance of more than 90% at 600nm. It is understood that the higher the transmittance, the more sunlight will penetrate the fixing strip 4 and be absorbed by the solar cell 1, thereby improving the photoelectric conversion efficiency of the module; therefore, by reasonably setting the transmittance of the fixing strip 4, the photoelectric conversion efficiency of the solar cell module can be ensured.

[0036] Specifically, the fixing strip 4 can be made of ETFE film, polysiloxane film or transparent polyimide film.

[0037] Furthermore, in this embodiment, the areal density of the solar cell 1 is no greater than 220 g / m². 2 With a photoelectric conversion efficiency of not less than 32%, it is beneficial to form a lighter solar cell string with higher photoelectric conversion efficiency, thereby improving its power-to-weight ratio.

[0038] Furthermore, in the embodiments of this application, the flexible base film 2 is a PET, PVC, or PE film with a thickness of no more than 100 micrometers and an areal density of no more than 100 g / m³. 2 This design ensures that the flexible base film 2 has good flexibility while also achieving a relatively light weight.

[0039] Furthermore, in the embodiments of this application, the interconnect sheet 3 is an aluminum foil or silver foil with a thickness of no more than 100 micrometers, so as to balance its good electrical and thermal conductivity with its light weight.

[0040] This application also proposes a method for fabricating a thin-film solar cell string module, including the following steps:

[0041] S1. Place the flexible base film 2 on a flat surface;

[0042] The plane can be a desktop, platform or other planar structure with good flatness and cleanliness; the flexible base film 2 is placed flat on the plane to ensure that the surface of the flexible base film 2 is free of wrinkles, particles, etc.

[0043] S2. Place the solar cell 1 sequentially onto the flexible base film 2;

[0044] According to the designed spacing, place the solar cell 1 from one end of the flexible base film 2 along its length to the other end to ensure that the solar cell 1 is in the correct position.

[0045] S3. Connect adjacent solar cells 1 via interconnecting sheet 3;

[0046] In this embodiment, the electrodes of the solar cell 1 are located on the front and back sides of the solar cell 1, respectively; one end of the interconnecting piece 3 is welded to the welding part on the front side of a solar cell 1, and extends from the welding part to the back side of another adjacent solar cell 1, and is welded to the welding part on the back side of another adjacent solar cell 1.

[0047] S4. Place the fixing strip 4 above the connection end of the adjacent solar cell 1 and above the edge end of the solar cell 1 located at the edge.

[0048] In this embodiment, the fixing strip 4 located on the solar cell 1 in the middle of the flexible base film 2 covers the front welding part of the solar cell 1, the gap between solar cells 1, the interconnecting piece 3, and the front area corresponding to the welding part on the back of the adjacent solar cell; the fixing strip 4 located at the edge of the solar cell 1 at the edge of the flexible base film 2 covers the front area corresponding to the welding part on the front or back of the solar cell 1, and extends to the outer part of the length of the solar cell 1; during operation, the fixing strip 4 should be flattened to avoid any warped parts.

[0049] S5. Adhere both ends of the fixing strip 4 to the flexible base film 2.

[0050] The two ends of the fixing strip 4 are bonded to the flexible base film 2 by adhesive. The material of the adhesive can be selected from the colloids commonly used in the preparation of solar cell modules in the prior art, and there are no restrictions, as long as it has good bonding strength.

[0051] Example 1:

[0052] like Figures 1 to 2As shown, a thin-film solar cell string assembly includes a flexible base film 2, multiple solar cells 1 connected in series, and a fixing strip 4; the multiple solar cells 1 are disposed on the flexible base film 2 along a first direction, and the ends of adjacent solar cells 1 that are close to each other are connected by interconnecting pieces 3, and the welding area of ​​the two forms a welding part; a fixing strip 4 is provided above the solar cells 1, the fixing strip 4 covers the welding part on the front side of the solar cells 1 and / or the area corresponding to the welding part on the back side of the solar cells 1, and the two ends of the fixing strip 4 are bonded to the flexible base film 2.

[0053] The flexible base film 2 is a long strip film. The solar cells 1 are arranged at equal intervals along its length and are located in the middle of the width direction of the flexible base film 2. The long side of the solar cell and the fixing strip 4 are both arranged along the width direction of the flexible base film 2. The two ends of the fixing strip 4 are bonded between the short side of the solar cell and the edge of the flexible base film 2.

[0054] The flexible base film 2 is a PVC film with a thickness of 80 micrometers; the solar cell 1 is a reverse triple-junction flexible thin-film solar cell 1 with an average areal density of 216 g / m³. 2 Interconnecting sheet 3 uses a silver strip with a length × width × thickness of 1.0mm × 0.5mm × 0.05mm; fixing strip 4 uses an EFTE film with a length × width × thickness of 45mm × 0.8mm × 0.05mm.

[0055] The above-mentioned thin-film solar cell string assembly was tested under AM0 spectrum, and the test results are shown in Appendix Table 1.

[0056]

[0057] In existing technologies, the specific power of thin-film solar cell string modules is typically around 600 g / m³. 2 The specific power of the thin-film solar cell string module in this application can reach 1202 W / kg. It can be seen that the specific power of the thin-film solar cell string module proposed in this application has been significantly improved, making it more suitable for application scenarios with lightweight and high-efficiency power generation requirements.

[0058] The technical solution adopted in this invention is:

[0059] The advantages and positive effects of this invention are:

[0060] (1) The present invention uses a fixing strip 4 to press the solar cell onto the flexible base film, and then the two ends of the fixing strip are bonded to the flexible base film. Compared with the traditional method of bonding the solar cell to the flexible base film, the manufacturing difficulty is reduced and the flatness of the solar cell string assembly is easier to control.

[0061] (2) By refining the connection structure and materials of flexible base film, interconnect sheet, solar cell and fixing strip, the solar cell string has a higher power-to-weight ratio, which is conducive to improving the power-to-weight ratio of thin film solar cell module and is more suitable for application scenarios with lightweight and high-efficiency power generation requirements.

[0062] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A thin-film solar cell string assembly, characterized in that: It includes a flexible base film, multiple solar cells connected in series, and a fixing strip; the solar cells are disposed on the flexible base film along a first direction; a fixing strip is provided above the solar cells, and the fixing strip is bonded to the flexible base film at both ends perpendicular to the first direction.

2. The thin-film solar cell string assembly according to claim 1, characterized in that: The ends of adjacent solar cells that are close to each other are connected by an interconnecting strip; the fixing strip extends from the connection end of one solar cell to the connection end of the adjacent solar cell to the interconnecting strip, or covers the edge of the solar cell located at the edge.

3. The thin-film solar cell string assembly according to claim 2, characterized in that: The fixing strip on the solar cell located at the edge protrudes from the adjacent edge.

4. The thin-film solar cell string assembly according to any one of claims 1-3, characterized in that: The electrodes of the solar cell are located on the front and back sides of the solar cell, respectively; the electrodes are provided with solder joints, and the two ends of the interconnect are soldered to the solder joints to form a welded part.

5. The thin-film solar cell string assembly according to claim 4, characterized in that: The fixing strip covers the welded portion on the front side of the solar cell and / or the front area corresponding to the welded portion on the back side of the solar cell.

6. The thin-film solar cell string assembly according to claim 1, characterized in that: The fixing strip is a transparent insulating film with a transmittance of more than 90% at 600nm.

7. The thin-film solar cell string assembly according to claim 1, characterized in that: The areal density of the solar cell is no greater than 220 g / m². 2 The photoelectric conversion efficiency is not less than 32%.

8. The thin-film solar cell string assembly according to claim 1, characterized in that: The flexible base film is a PET, PVC, or PE film with a thickness of no more than 100 micrometers and an areal density of no more than 100 g / m³. 2 .

9. The thin-film solar cell string assembly according to claim 1, characterized in that: The interconnect sheet is made of aluminum foil or silver foil, and its thickness is no more than 100 micrometers.

10. A method for preparing a thin-film solar cell string module, characterized in that, Includes the following steps: Place the flexible base film on a flat surface; The solar cells are placed sequentially on the flexible base film; The adjacent solar cells are connected by interconnecting sheets; The fixing strip is placed above the connection end of the adjacent solar cells and above the edge end of the solar cells located at the edge; The two ends of the fixing strip are bonded to the flexible base film.

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