Flexible thin film solar cell array interconnection structure
By employing a continuous "S"-shaped bending structure and stress-reducing design, the interconnection problem of flexible thin-film solar cell arrays under extreme temperature environments has been solved, achieving highly reliable and long-life connections that meet the requirements of extremely small-pitch thin-film solar cell arrays.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-17
- Publication Date
- 2026-04-03
AI Technical Summary
Existing flexible thin-film solar cell array interconnection structures are difficult to adapt to large deformations and strains under extreme temperature environments, and the interconnection structure design is difficult, making it impossible to achieve high reliability and long lifespan connections for thin-film solar cells.
The continuous "S"-shaped bend structure design includes a weak stiffness planar symmetrical structure, pads and stress-reducing fillets, combined with secondary shear stress arc segments and cross-sectional connection structures to achieve weak stiffness and high reliability of the interconnect structure.
It adapts to large deformations under extreme temperature environments, reduces solder joint tension, improves the reliability and lifespan of interconnect structures, enhances the wafer coverage rate, and meets the requirements of ultra-small pitch thin-film solar cell arrays.
Smart Images
Figure CN121793449A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solar cell array power technology, and relates to a flexible thin-film solar cell array interconnection structure. Background Technology
[0002] Currently, with the rapid development of flexible thin-film solar array technology, compared to traditional rigid solar arrays (which deploy rigid solar cells and circuits on a rigid panel composed of aluminum honeycomb and carbon fiber mesh), flexible thin-film solar arrays offer advantages such as a higher power-to-weight ratio (the ratio of solar array power generation to its mass) and a higher power-to-volume ratio (the ratio of solar array power generation to its volume in its collapsed state). Furthermore, because thin-film solar cells are 70% thinner than rigid solar cells (rigid solar cells are 0.145mm–0.225mm thick; thin-film solar cells are only 0.035–0.04mm thick), they can achieve better bending deformation without compromising power generation efficiency. Flexible thin-film solar arrays are suitable for missions with specific requirements, such as space-wound flexible solar arrays designed for a larger expansion-to-contraction ratio, and ultra-lightweight spacecraft energy systems. Therefore, space thin-film solar arrays are superior to rigid solar arrays in terms of areal density, power-to-weight ratio, and other technical indicators, and will become the future trend in high-power spacecraft power technology.
[0003] like Figure 1As shown, traditional rigid solar cell array technology is relatively mature, mainly consisting of a rigid substrate 21, substrate adhesive 22, rigid solar cells 23, cover adhesive 24, glass cover 25, and interconnection structures 26 arranged on the upper and lower electrodes of the rigid cells. The rigid solar cells 23 are relatively thick and not easily bent, with their positive and negative electrodes located on the upper and lower sides of the cell. The interconnection structure 26 primarily connects the cells in series, providing the required voltage and current, and its two ends are welded to the positive and negative electrodes of the cells, respectively. To adapt to the alternating high and low temperature environment in space, and to accommodate the displacement differences caused by thermal expansion and contraction, the solar cell array employs an "Ω" shape to achieve a weak spring effect, thus adapting to the stretching and compression effects generated by the solar cell array. The biggest difference between flexible thin-film solar arrays, which have been developed in recent years, and rigid solar cells lies in their thickness. Rigid solar cells are typically 145μm to 225μm thick, while thin-film solar cells are generally only 30μm to 40μm thick. This results in the positive and negative electrodes of the thin-film solar cell being located on opposite sides of the front of the cell. Consequently, the design of the interconnect structure differs from that of a rigid solar cell array, and the smaller size of the interconnect structure presents significant design challenges. Furthermore, under extreme temperature conditions, such as the lunar surface where temperatures range from -180℃ to +150℃, conventional "Ω"-shaped interconnect structures cannot accommodate the greater displacement and strain requirements of solar cell arrays. Therefore, designing a highly reliable and long-life interconnect structure that meets the interconnect requirements of thin-film solar cell arrays while also considering the effects of extreme temperature environments presents the following challenges:
[0004] 1) Thin-film solar cells use positive and negative electrodes on the same side, meaning the positive and negative electrodes are located on the same surface of the cell, and the thickness is relatively thin, making it impossible to achieve a weak stiffness and stress reduction design in the vertical plane, i.e. the thickness direction.
[0005] 2) In order to achieve a higher cell density, the spacing between solar cells is usually required to be narrow, typically 0.8mm to 1mm. This results in a smaller area for interconnect structure design, a smaller slot width, and greater difficulty in configuration design.
[0006] 3) Under extreme temperature conditions, solar cell arrays will undergo significant deformation and strain, requiring the interconnect structure to adapt to even greater displacement deformation. Achieving structural stress reduction under large deformation presents a certain challenge. Summary of the Invention
[0007] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a flexible thin-film solar cell array interconnection structure.
[0008] The solution of this invention is: a flexible thin-film solar cell array interconnection structure, including a continuous "S"-shaped bend structure and two pads; the continuous "S"-shaped bend structure has a 90° bend angle at each bend, and the overall transverse direction is planar symmetrical to achieve the weak stiffness characteristics of the interconnection structure; one pad is located at the beginning of the continuous "S"-shaped bend structure and the other is located at the end, and they are respectively welded to the positive and negative electrodes of the thin-film solar cell, and the two pads are located on the same side of the transverse X-axis, which can adapt to the interconnection requirements of flexible thin-film solar cell arrays with narrower spacing, and the area where the two pads are located is axially symmetrical along the transverse Y-axis.
[0009] Furthermore, the continuous "S"-shaped bend structure is made of silver.
[0010] Furthermore, the narrower spacing between the panels in the flexible thin-film solar cell array is 0.8 mm to 1 mm.
[0011] Furthermore, the continuous "S"-shaped bending structure is installed on the back side of the flexible thin-film solar cell array; one of the two pads is bent from the back side of the flexible thin-film solar cell array to the front side and then welded to the electrode on the front side of the flexible thin-film solar cell; the other is directly welded to the electrode on the back side of the flexible thin-film solar cell.
[0012] Furthermore, each bend of the continuous "S"-shaped bending structure is provided with a stress-reducing fillet. When the interconnecting structure is subjected to alternating high and low temperature environments, the stress-reducing fillet can reduce its stress level.
[0013] Furthermore, the stress fillet has a secondary shear stress arc segment at a specified distance outside its circumference, which is cocentric with the stress fillet, in order to reduce stress concentration distribution and improve the reliability and lifespan of the interconnection structure.
[0014] Furthermore, the arc angle range of the secondary shear stress arc segment is 160 to 180°.
[0015] Furthermore, several cross-sectional connection structures are provided in the continuous "S" shaped bend structure to increase the planar structural stiffness of the interconnection structure and facilitate the maintenance of the shape during the welding process.
[0016] Furthermore, after the cross-sectional connection structure is welded, it can be shortened to increase stress-reducing characteristics; or it can be left uncut and deformed and fractured under high and low temperature environments after being placed on the rail, releasing the stress-reducing characteristics of the interconnection structure.
[0017] Furthermore, the interconnection structure is formed by laser cutting or precision die stamping; the precision of laser cutting or precision die stamping is ≥0.02mm.
[0018] The advantages of this invention compared to the prior art are:
[0019] (1) The present invention adopts a continuous “S” shaped bend structure symmetrical design to realize the weak stiffness characteristics of the interconnect structure in the longitudinal direction of the thickness direction, adapt to the large deformation characteristics of the interconnect structure under extreme temperature environment, and help reduce the tension of the interconnect structure solder joints and improve environmental adaptability.
[0020] (2) The present invention places the pads connected to the positive and negative electrodes of the solar cell array on the same side, which can adapt to the requirements of the solar cell array with extremely small gaps and greatly increase the solar cell array area.
[0021] (3) The continuous “S” shaped bend structure of the present invention has a cross-sectional connection structure in the middle, which connects the interconnect structure as a whole, increases the rigidity of the planar structure and facilitates the shape maintenance during the welding process; at the same time, stress-reducing rounded corners are provided at both ends of the slot of the continuous “S” shaped bend structure, which can effectively reduce the stress concentration distribution of the interconnect structure under large deformation, and improve the reliability and long service life of the interconnect structure. Attached Figure Description
[0022] Figure 1 This is a cross-sectional schematic diagram of the interconnect structure used in traditional space solar cells;
[0023] Figure 2 This is a schematic diagram of the planar weak stiffness and stress-reducing interconnection structure provided by the present invention;
[0024] Figure 3 This is a front view of the interconnection structure of the present invention;
[0025] Figure 4 This is a rear view of the interconnect structure of the present invention. Detailed Implementation
[0026] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments.
[0027] A flexible thin-film solar cell array interconnect structure includes a weakly rigid stress-reducing structure and pads 3. The weakly rigid stress-reducing structure is composed of a continuous planar "S"-shaped bend structure 1, with pads 3 located at the tail end of the weakly rigid stress-reducing structure. The planar interconnect structure is composed of a continuous planar "S"-shaped bend structure 1. The weakly rigid stress-reducing structure is made of silver material; the bend angle of the S-shaped traces remains at 90° as shown in the figure.
[0028] The planar "S"-shaped bend structure 1 is an axisymmetric structure in the horizontal direction. The horizontal direction is a horizontal plane perpendicular to the thickness direction. On the horizontal plane, a two-dimensional coordinate system is defined, with the center point of the "S"-shaped bend structure 1 as the origin of the coordinate system. The X-axis and Y-axis are perpendicular to each other. The two ends of the "S"-shaped bend structure 1 are located on the same side of the X-axis and are symmetrical with respect to the Y-axis.
[0029] The planar interconnect structure achieves the characteristic of weak stiffness in the longitudinal (thickness) direction of the interconnect structure, which can better adapt to the influence of extreme temperature environment in space, and can reduce the solder joint tension on pad 3 under the alternating high and low temperature environment of the solar cell array. The continuous "S"-shaped bend structure 1 achieves the characteristic of weak stiffness in the transverse direction of the interconnect structure, which can better adapt to the influence of extreme temperature environment in space, and can reduce the solder joint tension on pad 3 under the alternating high and low temperature environment of the solar cell array.
[0030] The end of the slot of the continuous "S" shaped bend structure 1 is provided with stress-reducing fillet 12. Under the alternating action of high and low temperature environment, the stress of the interconnect structure can be reduced through the stress-reducing fillet 12.
[0031] The continuous "S"-shaped bend structure 1 has a cross-sectional connecting structure 4 in the middle, which connects the interconnecting structures as a whole, increasing the rigidity of the planar structure and facilitating shape maintenance during the welding process. After welding, it can be shortened to increase stress-reducing characteristics. Alternatively, it can be left uncut, allowing deformation and fracture to occur under high and low temperature environments after rail welding, releasing the stress-reducing characteristics of the interconnecting structure.
[0032] The tail end of the continuous "S"-shaped structure 1 is a pad 3. The two pads 3 are located on the same side and are used for welding to the positive and negative electrodes of the thin-film solar cell, respectively. The interconnect structure is formed by laser cutting or precision die stamping, with a cutting or forming accuracy greater than or equal to 0.02 mm.
[0033] The continuous "S"-shaped bend structure 1 has a stress-reducing fillet 12 at the bend, and a secondary shear stress arc segment 13 is provided above the stress fillet 12 to reduce stress concentration and improve the reliability and lifespan of the interconnection structure. The secondary shear stress arc segment 13 is an arc structure with the stress-reducing fillet 12 of the arc structure as its center; the arc angle of the secondary shear stress arc segment 13 ranges from 160° to 180°; the arc groove ranges from 0.15° to 0.2mm; and the distance between the secondary shear stress arc segment 13 and the stress-reducing fillet 12 ranges from 0.2° to 0.4mm.
[0034] The continuous "S"-shaped bend structure 1 has a cross-sectional connecting structure 4 in the middle, which connects the interconnecting structures as a whole, increases the rigidity of the planar structure, and facilitates shape maintenance during the welding process. The number and specific location of the cross-sectional connecting structures 4 are not specifically limited and are determined according to actual needs.
[0035] The tail end of the continuous "S"-shaped bend structure is a solder pad 3, located on the same side, used for soldering to the positive and negative electrodes of the thin-film solar cells, thereby achieving interconnection of the solar cell modules. This design can accommodate the requirements of thin-film solar cell arrays with smaller gaps, improving the overall cell layout efficiency of the solar cell array.
[0036] like Figures 2-4The invention is further described in detail below. The structure of the invention includes a weak-stiffness stress-reducing structure, a cross-sectional connection structure 4, and a solder pad 3. Further, it consists of a continuous planar "S"-shaped bend structure 1, wherein the bend of the continuous "S"-shaped structure 1 is provided with a stress-reducing fillet 12, and a secondary shear stress arc segment 13 is provided above the stress fillet 12. This can significantly reduce stress concentration in the interconnect structure. The continuous "S"-shaped bend structure 1 can achieve the lateral weak-stiffness characteristics of the interconnect structure. The tail end of the continuous "S"-shaped structure 1 is a solder pad 3, used for welding with the positive and negative electrodes of the thin-film solar cell to complete the interconnection of the solar cell module. The continuous "S"-shaped bend structure 1 has a cross-sectional connection structure 4 in the middle, connecting the interconnect structure as a whole, increasing the stiffness of the planar structure and facilitating shape maintenance during the welding process. After welding, it can be shortened to increase stress-reducing characteristics. Alternatively, it can be left uncut, undergoing deformation and fracture under high and low temperature environments after welding, releasing the stress-reducing characteristics of the interconnect structure. The key feature of this structure is the reduction of the gap in the series connection direction of the cells, thereby increasing the overall cell density of the solar array. The planar interconnection structure of this invention employs a continuous "S"-shaped bend design, which offers high reliability.
[0037] like Figure 3 , 4 As shown, the interconnect structure is located on the back of the solar cell array. After the pad 3 is bent, it is welded to the electrode on the front of the thin-film solar cell and then protected with adhesive. The innovative back-side design enables small-gap adaptation, and the structure facilitates manual operation, mechanical gripping and release, and automated welding operations.
[0038] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.
Claims
1. A flexible thin-film solar cell array interconnection structure, characterized in that: It includes a continuous "S" shaped bend structure (1) and two pads (3); the continuous "S" shaped bend structure (1) has a 90° bend angle at each bend and the whole structure is symmetrical in the horizontal direction to achieve the weak stiffness characteristics of the interconnection structure; the two pads (3) are located at the beginning of the continuous "S" shaped bend structure and the other at the end, respectively, and are welded to the positive and negative electrodes of the thin film solar cell. The two pads (3) are located on the same side of the horizontal X-axis, which can adapt to the interconnection requirements of flexible thin film solar cell array with narrower spacing. The area where the two pads (3) are located is symmetrical along the horizontal Y-axis.
2. The flexible thin-film solar cell array interconnection structure according to claim 1, characterized in that: The continuous "S" shaped bend structure (1) is made of silver.
3. The flexible thin-film solar cell array interconnection structure according to claim 1, characterized in that: The narrower spacing between the panels in the flexible thin-film solar cell array is 0.8 mm to 1 mm.
4. The flexible thin-film solar cell array interconnection structure according to claim 1, characterized in that: The continuous "S" shaped bending structure (1) is installed on the back side of the flexible thin-film solar cell array; one of the two pads (3) is bent from the back side of the flexible thin-film solar cell array to the front side and then welded to the electrode on the front side of the flexible thin-film solar cell; the other is directly welded to the electrode on the back side of the flexible thin-film solar cell.
5. The flexible thin-film solar cell array interconnection structure according to claim 3, characterized in that: The continuous "S" shaped bend structure (1) is provided with stress-reducing fillet (12) at each bend. When the interconnected structure is subjected to alternating high and low temperature environments, the stress-reducing fillet (12) can reduce its stress level.
6. The flexible thin-film solar cell array interconnection structure according to claim 5, characterized in that: The stress fillet (12) has a secondary shear stress arc segment (13) at a specified distance outside its circumference, which is co-centered with the stress fillet (12) to reduce stress concentration distribution and improve the reliability and long life of the interconnection structure.
7. The flexible thin-film solar cell array interconnection structure according to claim 6, characterized in that: The arc angle range of the secondary shear stress arc segment (13) is 160 to 180°.
8. The flexible thin-film solar cell array interconnection structure according to claim 1, characterized in that: Several cross-sectional connection structures (4) are provided in the continuous "S" shaped bend structure (1) to increase the planar structural stiffness of the interconnection structure and facilitate the shape maintenance during the welding process.
9. The flexible thin-film solar cell array interconnection structure according to claim 8, characterized in that: After the cross-sectional connection structure (4) is welded, it can be shortened to increase stress reduction characteristics; or it can be left uncut and deformed and fractured under high and low temperature conditions after being placed on the rail, thus releasing the stress reduction characteristics of the interconnection structure.
10. The flexible thin-film solar cell array interconnection structure according to claim 1, characterized in that: The interconnect structure is formed by laser cutting or precision die stamping; the precision of laser cutting or precision die stamping is ≥0.02mm.