A stretchable flexible braided photovoltaic array and its fabrication method

Abstract

This invention relates to a stretchable flexible braided photovoltaic array and its fabrication method, belonging to the field of photovoltaic technology. The stretchable flexible braided photovoltaic array is formed by weaving several stretchable strip-shaped battery units into an array. Each strip-shaped battery unit includes a strip-shaped substrate circuit and several photovoltaic devices. The strip-shaped substrate circuit is an FPCB circuit, including a flexible substrate and a conductive layer. The strip-shaped battery unit has an island-bridge structure, with the island structure serving as photovoltaic device pads on which photovoltaic devices are soldered. The bridge structure is a bistable paper-cut structure formed by cutting slits in the strip-shaped substrate circuit. This invention improves the design efficiency of the photovoltaic array through programmable parametric design. The designed photovoltaic array is protected from stress damage during deformation and imparts high ductility and rapid deformation recovery capability to the substrate, achieving an effective working area of ​​100%, significantly improving the tensile performance, photoelectric conversion efficiency, and stability of the flexible photovoltaic array.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, specifically relating to a stretchable flexible braided photovoltaic array and its preparation method. Background Technology

[0002] Photovoltaic power generation is a technology that directly converts light energy into electrical energy using the photovoltaic effect at the semiconductor interface. It is widely used in various power generation fields. Due to its low cost and high stability, photovoltaics is now widely used in energy supply. Under sufficient sunlight, photovoltaic systems can provide a stable power supply, achieving completely independent energy supply without relying on any other energy source.

[0003] Wearable devices are developing rapidly, but there is a lack of self-powered technologies that can provide long-term, stable power. Since wearable devices need to be permanently mounted on the surfaces of various flexible biological bodies, there are requirements regarding their flexibility, tensile strength, and weight. Photovoltaic technology relies on solar energy for power generation, and its sustainability offers a significant advantage among self-powered technologies. However, traditional silicon solar cells are brittle and rigid, with poor mechanical strength, and cannot be bent or folded, thus failing to meet the requirements of wearable devices. Therefore, there is a need to develop flexible solar cells.

[0004] Currently, there are two main approaches to flexible photovoltaics:

[0005] (1) Material innovation: Develop flexible optoelectronic materials for processing and manufacturing, such as perovskite solar cells and organic solar cells. Although these types of solar cells exhibit good flexibility, they have problems with stability, cost, processing complexity and material cleanliness, making it difficult to realize practical applications.

[0006] (2) Structural innovation: The tensile and bending properties of traditional rigid solar cells are improved by combining them with flexible substrates and special mechanical structures such as paper-cutting, origami, island bridge, and corrugated structures. This approach is mostly based on traditional silicon-based solar cells, which have lower costs, higher conversion efficiency, and higher stability. It has already achieved very promising commercial applications.

[0007] For example, invention patent CN119031810A discloses a flexible stretched photovoltaic module and its manufacturing method. The module includes a flexible polyimide film substrate and photovoltaic devices. Circuitry is fabricated on the substrate, and slits are cut to divide the flexible substrate into specific unit paper-cut structures. The devices are connected via circuitry to form an array. This structural component optimizes the flexibility of the original rigid battery by utilizing the flexibility of the substrate and the stretchability of the cut structures. However, this component has a low stretchability and a reduced effective working area of ​​the devices.

[0008] For example, invention patent CN118039717A discloses a stretchable solar cell array and its fabrication method. The component, from bottom to top, consists of: an elastic substrate, an electrospun fiber layer, a liquid metal circuit, and a solar cell. The liquid metal circuit forms a loop that connects to the solar cell via electrospun fiber thin film units in the electrospun fiber layer. However, the materials used in manufacturing this component are expensive, the liquid metal circuit suffers from instability and leakage risks, and the device has a relatively low effective working area.

[0009] Therefore, more efficient and durable photovoltaic designs are needed to meet the requirements of flexible devices, in order to ensure the long-term stable operation and service life of the equipment. Summary of the Invention

[0010] The purpose of this invention is to provide a stretchable flexible woven photovoltaic module and its preparation method, which improves the mechanical properties of flexible photovoltaic arrays and significantly enhances the tensile properties and photoelectric conversion efficiency of flexible photovoltaic arrays.

[0011] To achieve the objectives of this invention, the following technical solution is provided:

[0012] A stretchable flexible woven photovoltaic array is formed by weaving together several strip-shaped battery cells.

[0013] The strip-shaped battery unit includes a strip-shaped substrate circuit and several photovoltaic devices, wherein the strip-shaped substrate circuit is an FPCB circuit, which includes a flexible substrate and a conductive layer.

[0014] This invention weaves a flexible substrate circuit (FPCB) and several photovoltaic devices into an array using a braiding method, solving the technical problem that traditional rigid photovoltaic modules are difficult to adapt to dynamic curved surfaces and high-stretch scenarios. Furthermore, the braided layout forms a distributed circuit network, which not only improves energy harvesting efficiency but also reduces the impact of local fractures on overall performance through redundant design, significantly increasing the effective working area of ​​the photovoltaic array.

[0015] Preferably, the strip-shaped battery unit is an island-bridge structure, the island structure is a photovoltaic device pad, and a photovoltaic device is welded on the top of the photovoltaic device pad; the bridge structure is a bistable paper-cut structure formed by cutting the strip-shaped substrate circuit to create gaps.

[0016] This invention is based on the use of solder paste to fix photovoltaic devices in rigid island-shaped pads in an island-bridge structure, ensuring that the photovoltaic array is protected from stress damage during deformation. The bridge-shaped bistable paper-cut structure formed by cutting imparts high ductility and rapid deformation recovery capability to the substrate through a controllable folding or unfolding mechanism. The topology optimization of the bridge-shaped bistable paper-cut structure further disperses strain and enhances cycle durability, providing a reliable and continuous energy supply solution for applications such as wearable devices and flexible robots.

[0017] Preferably, the ratio of the length of the bridge structure to the length of the island structure is 1.

[0018] The elongation of the overall braided circuit is related to the length ratio of the island structure (which does not undergo stretching) to the bridge bistable structure (which bears the main tensile deformation). Choosing the above length ratio ensures that the photovoltaic array is protected from stress damage during deformation, and imparts high ductility and rapid deformation recovery capability to the substrate, significantly improving the mechanical strength of the flexible photovoltaic array and achieving lightweight photovoltaic array.

[0019] Preferably, the ratio of the thickness at the deformed end to the thickness at the fixed end of the bistable paper-cutting structure is 1.

[0020] By adjusting the thickness ratio of the deformable end to the fixed end, multi-dimensional optimization is achieved: the deformable end preferentially deforms elastically to absorb external strain and disperse stress, while the fixed end remains rigid to stably support the functional unit and avoid device damage; the stiffness gradient formed by the thickness difference can reduce the critical energy barrier for bistable switching, improving the deformation response speed and controllability; at the same time, the optimization of strain distribution significantly reduces stress concentration at the connection, delays crack propagation, and enhances the cycle durability of the photovoltaic array; in addition, the fixed end adapts to the mechanical stability requirements of the photovoltaic array, while the ultra-thin design of the deformable end is compatible with high elongation, balancing protection and stretchability within a limited space, ultimately achieving efficient energy transfer and long-term reliable operation on complex curved or dynamic surfaces.

[0021] Preferably, the ratio of the width to the length of the gap in the bistable paper-cutting structure is 0.15.

[0022] Within the aforementioned range, the aspect ratio guides strain to a uniform distribution along a serpentine path, avoiding localized stress concentration, thereby delaying crack propagation and enhancing cyclic durability. Simultaneously, by extending the bending path of the slit, the bistable paper-cut structure can achieve ultra-high elongation rates during stretching through a controllable folding or unfolding mechanism, while maintaining the stability of bistable switching. Furthermore, it balances structural stiffness and flexibility; where processing precision allows, a larger aspect ratio is preferred. To achieve higher tensile properties.

[0023] Preferably, the weaving method includes one or more of biaxial weaving and triaxial weaving.

[0024] By selecting a weaving method, a stretchable and flexible woven photovoltaic array is formed, which, in conjunction with a suitable bridge-to-island width ratio and island-bridge structure, achieves 100% effective working area.

[0025] Preferably, the flexible substrate is a polyimide film flexible substrate.

[0026] Preferably, the photovoltaic device is an IBC solar cell unit, with a light absorption area on the front and an integer number of alternating positive and negative electrode areas on the back.

[0027] More preferably, the size of the IBC solar cell unit is smaller than that of the island structure.

[0028] By using a mask of a specific shape to control the solderable area of ​​the electrodes, the solderable areas of the positive and negative electrodes are arranged on both sides and connected to the pads on the substrate circuit. This is coordinated with the size of the photovoltaic device to ensure that the coverage after weaving reaches 100%, significantly improving the effective working area of ​​the photovoltaic array.

[0029] The stretchable strip-shaped battery cell has external solder pads at both ends for connection to external circuits.

[0030] Preferably, each strip battery cell has external solder pads at both ends for connecting the strip battery cells in series or parallel via soldered wires or pluggable interfaces.

[0031] The stretchable strip-shaped battery cells are connected in parallel, which reduces the voltage loss of the overall circuit.

[0032] More preferably, the voltage and current parameters of the stretchable flexible braided photovoltaic array are proportional to the number of stretchable strip-shaped battery cells and photovoltaic devices.

[0033] Each photovoltaic (PV) device has a voltage of U and a current of I. A single stretchable strip-shaped solar cell unit contains n PV devices, and each stretchable strip-shaped solar cell unit has a current of I and a voltage of nU. The current I of a single PV device is positively correlated with its area; the current of a single PV device can be adjusted by changing its size. The voltage of a single PV device is related to the performance parameters of the IBC (Integrated Circuit Cell) itself. Therefore, the electrical parameters of the flexible braided PV array can be adjusted by setting the number of stretchable strip-shaped solar cell units and the size and number of the PV devices they support.

[0034] Preferably, the strip-shaped substrate circuit has specific wire routing, and the wires are copper wires.

[0035] This invention also provides a method for fabricating a programmable, stretchable, flexible braided photovoltaic array, comprising the following steps:

[0036] (1) Draw the target surface of the stretchable flexible braided photovoltaic array;

[0037] (2) Determine the braided array parameters based on the current and voltage parameters, divide the target surface according to the braided array parameters to obtain the island bridge structure position, and connect the island bridge structure positions into warp and weft lines to obtain different flexible braided photovoltaic array design schemes;

[0038] (3) Based on different flexible braided photovoltaic array design schemes, construct array mechanical mesh models, perform mechanical model analysis on the models, and optimize the braided array parameters;

[0039] (4) Provide a flexible substrate, determine the island bridge structure on the flexible substrate according to the braided array parameters to form a strip battery unit, and braid the strip battery unit into a stretchable flexible braided photovoltaic array by braiding.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention combines island bridge structure and bistable paper-cutting structure to form stretchable strip battery unit, ensuring that the photovoltaic array is protected from stress damage during deformation, and giving the substrate high ductility and fast deformation recovery capability, thereby improving the tensile performance of the circuit while ensuring circuit stability.

[0042] (2) The parallel connection of photovoltaic devices combined with the braided layout forms a distributed circuit network. The compact structure can ensure 100% coverage. Furthermore, the photovoltaic devices based on IBC solar cells not only improve energy collection efficiency, but also reduce the impact of local fractures on overall performance through redundant design, significantly increasing the photoelectric conversion efficiency of the photovoltaic array.

[0043] (3) The external parameters such as the size, shape, and density of the braided structure, as well as the electrical parameters such as the voltage and current of the overall braided circuit, can be designed by programmable parameterization by adjusting the external parameters of the strip, the number of units, and the total number of strips, which greatly improves the design efficiency of the photovoltaic array. The final designed braided flexible photovoltaic array has excellent tensile and bending performance and can be attached to and adapted to a variety of complex surfaces. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the stretchable flexible braided photovoltaic array provided in this embodiment.

[0045] Figure 2 The diagram shows two specifications of braided circuit structures provided in this embodiment.

[0046] Figure 3 This is a schematic diagram of the structure of the stretchable FPCB circuit provided in this embodiment.

[0047] Figure 4 This is a schematic diagram of the stretching of a single stretchable strip-shaped battery cell provided in this embodiment.

[0048] Figure 5 This is a stretched schematic diagram of the bistable paper-cutting structural unit provided in this embodiment.

[0049] Figure 6 This is a schematic diagram of the relevant structural parameters of the bistable paper-cutting structure provided in this embodiment.

[0050] Figure 7 The stress-strain curve of a single stretchable strip battery cell under the optimal parameters provided in this embodiment.

[0051] Figure 8 This is a schematic diagram of the photovoltaic device provided in this embodiment.

[0052] Figure 9 This is a schematic diagram of a series-connected stretchable flexible braided photovoltaic array provided in this embodiment.

[0053] Figure 10 This is a schematic diagram of the stretchable flexible braided photovoltaic array provided in this embodiment being bent.

[0054] Figure 11 This is a schematic diagram of the stretchable flexible braided photovoltaic array provided in this embodiment under tension.

[0055] Figure 12 This is a schematic diagram of the stretchable flexible braided photovoltaic array provided in this embodiment being subjected to bending and stretching.

[0056] Figure 13 This is a schematic diagram of the programmable target surface structure provided in this embodiment.

[0057] Figure 14 This is a schematic diagram of the programmable design topology provided in this embodiment.

[0058] Figure 15 This is a schematic diagram of programmable design mechanics optimization provided in this embodiment.

[0059] In the figure, 1 and 2 are stretchable strip-shaped substrate circuits; 11 is a photovoltaic device; 111 is the non-electrode region of the IBC cell; 112 is the negative electrode region of the IBC cell; 113 is the positive electrode region of the IBC cell; 114 is a polyimide tape mask; 12 is an FPCB circuit; 121 is an external pad; 122 is an island structure; 123 is a bistable paper-cut structure; 1231 is a bistable paper-cut slit unit; 1232 is the deformation end of the bistable paper-cut slit unit; 1233 is the fixed end of the bistable paper-cut slit unit; 124 is a photovoltaic device pad; 2 and 3 are stretchable strip-shaped substrate circuits; 3 is a series external circuit; 4 is an array mechanical mesh model; 41 is the initial boundary; 42 is the target boundary; 43 is the internal mesh point; 44 is the internal mesh edge. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and given in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0061] like Figure 1 The diagram shown is a schematic of a 5×5 stretchable flexible braided photovoltaic array provided in this embodiment, including 5 strips of 2-unit strip stretchable braided circuit (1) and 5 strip stretchable braided circuits of 3-units (2).

[0062] like Figure 2 The diagram shows two braided structures in this example. Each braided circuit includes an FPCB circuit (12) and a photovoltaic device (11) soldered onto it.

[0063] like Figure 3 The diagram shown is a schematic of the FPCB circuit in this example. The overall circuit outline is an island-bridge structure, in which the island structure supports the photovoltaic device (11), and the photovoltaic device pads (124) are set up for soldering with solder paste. The outer frame of the bridge structure circuit is cut into a specific shape of slots to form a bridge structure, and the internal circuits are designed into a special serpentine structure along the shape of the slots.

[0064] like Figure 4 As shown, this is a schematic diagram of the stretching of a single braided circuit in this example. During the stretching process, the bistable paper-cut structure (123) of the bridge-type structure deforms and opens, while the island-type structure (122) remains largely unchanged. Therefore, the entire braided circuit achieves a large-scale stretching through the bistable paper-cut structure, while the island-type structure supporting the photovoltaic device remains largely unchanged, ensuring that the photovoltaic device (11) will not be damaged due to deformation stress during the stretching process.

[0065] In this example, the elongation of the overall braided photovoltaic array circuit is related to the length ratio of the island structure (which does not undergo stretching) to the bridge-type bistable structure (which bears the main tensile deformation). The length of the bridge is... The length of the island is The bridge-to-island ratio is defined as:

[0066] .

[0067] like Figure 5 The diagram shown is a stretching schematic of the bistable paper-cutting structure (123). Figure 5 (a) is its first stable state. Figure 5 (b) is its second stable state. The stretching process of the bistable paper-cutting structure mainly involves the deformation of the bistable paper-cutting gap unit (1231) when subjected to axial tensile force F. The gaps open and the parallel edges of the two gaps are transformed into a shape where the two gaps are approximately symmetrical. Throughout the process, the overall shape transitions from the first stable state to the second stable state and finally reaches the second stable state, achieving large deformation stretching.

[0068] like Figure 6 The diagram shows the relevant structural parameters of the bistable paper-cutting structure in this example. The thickness of the deformable end (1232) of the bistable paper-cutting gap unit is... The thickness of the fixed end (1233) of the bistable paper-cutting gap unit is The thickness ratio is defined as:

[0069] .

[0070] The length of the bistable paper-cutting gap unit (1231) is The width of the bistable paper-cutting gap unit (1231) is The aspect ratio is defined as:

[0071] .

[0072] The elongation of braided photovoltaic array circuits is related to three parameters: bridge-to-island ratio, thickness ratio, and width-to-length ratio. The elongation varies with... The rate of increase in stretching increases with the increase in the value of the material. It decreases as the value increases. Preferred For an island-bridge structure with a stretch rate of 1, the stretching rate is maximized, resulting in the greatest stretching benefit and achieving lightweight photovoltaic devices. The stretching rate of the braided photovoltaic array circuit increases with... The value decreases as the machining equipment increases; therefore, a smaller value is preferred when the machining equipment's precision allows. This allows for higher tensile properties. The elongation of braided photovoltaic array circuits increases with... The increase in size leads to improvement; given the allowable machining accuracy, a larger size is preferred. It can achieve higher tensile properties.

[0073] The machining accuracy in this example is 0.03 mm. Figure 7 The results show that a 75 μm thick polyimide film was used in the actual test of this example. For 1, For 1, The stress-strain curve of the braided circuit measured at a value of 0.15 shows that the maximum tensile strength can reach over 100%.

[0074] like Figure 8 The photovoltaic device (11) used in this example is shown. This device is based on a specific cell unit of an IBC solar cell, with the front side being the light-absorbing surface and the back side consisting of a non-electrode area (111), a negative electrode area (112), and a positive electrode area (113) of the IBC cell arranged sequentially. The solderable areas of the electrodes are controlled by attaching a polyimide tape mask (114) of a specific shape, aligning the solderable areas of the positive and negative electrodes on both sides for connection to pads on the circuit. The cell size is preferably equal to the island structure (122) size to ensure 100% coverage after weaving. Other types of cells that guarantee size and single-sided electrode connection, such as gallium arsenide cells, can be used. All photovoltaic device units are connected in parallel within a single stretchable strip cell unit. Figure 3 The circuit has external solder pads (121) at both ends for connection to external circuits, which can reduce the voltage loss of the overall circuit.

[0075] In this example, the overall photovoltaic array is woven using the classic "one-on-one" biaxial weaving method, the most classic technique in warp and weft weaving. The island-shaped structure (122) carrying the photovoltaic devices is placed on top of the bridge-shaped structure, forming a stretchable and flexible woven photovoltaic array. When the bridge-island length ratio is guaranteed... When the island-type unit has a uniform length and width, it can achieve 100% effective working area, significantly improving photoelectric conversion efficiency.

[0076] Furthermore, each photovoltaic (PV) device has a voltage of U and a current of I. A single stretchable strip-shaped solar cell unit contains n PV devices, and each stretchable strip-shaped solar cell unit has a current of I and a voltage of nU. The current I of a single PV device is positively correlated with its area; the current of a single PV device can be adjusted by changing its size. The voltage of a single PV device is related to the performance parameters of the IBC (Integrated Circuit) cells used. Therefore, the electrical parameters of the flexible braided PV array can be adjusted by setting the number of stretchable strip-shaped solar cell units and the size and number of the PV devices they support.

[0077] The battery cells used in this example have a size of 4.85 mm × 4.85 mm, a voltage of 0.6 V, and a current of 90 mA. The braided circuit of the two cells has a voltage of 0.6 V and a current of 180 mA; the braided circuit of the three cells has a voltage of 0.6 V and a current of 360 mA. Figure 9 The diagram shows a braided photovoltaic array where all stretchable strip-shaped solar cell cells are connected in series, resulting in a voltage of 6 V and a current of 180 mA. Specifically, as shown... Figure 9As shown, since each braided strip has external solder pads (121) at both ends, two identical series external circuits (3) can be obtained. When a part of the braided circuit fails, the backup circuit traces can work, giving the braided photovoltaic array a significant advantage in stability. The braided photovoltaic array has good flexibility and tensile strength, such as Figure 12 , 13 Figure 14 shows a schematic diagram of a circuit subjected to bending, stretching, and combined deformation.

[0078] This invention also provides a method for fabricating a programmable, stretchable, flexible braided photovoltaic array, such as... Figures 13-15 As shown, this invention enables programmability of circuit topology through a warp and weft weaving process. On complex curved surfaces or dynamically deformable surfaces, the spatial arrangement density of the weaving strips and the node connection method can be adjusted to dynamically adapt to the geometry and mechanical requirements of the target surface. The Grasshopper plugin in Rhino software allows for topological analysis and design of the curved surface to obtain different schemes. Kangaroo software is then used to evaluate and optimize these schemes to obtain the optimal weaving scheme. A flexible substrate is provided, and island bridge structures and bistable paper-cut structures are determined on the flexible substrate based on the weaving array parameters to form stretchable strip-shaped battery units. These stretchable strip-shaped battery units are then woven into a stretchable flexible woven photovoltaic array.

[0079] Specific examples Figure 13 As shown, the target surface is drawn in Rhino. Based on the required circuit current and voltage parameters, the corresponding braiding array parameters (n×m) are determined. The target surface is then divided according to the n×m parameters to obtain the island bridge structure positions of the braiding array. The nodes are connected to form warp and weft threads to obtain the target braiding array. For example... Figure 14 (a) shows a 4×5 braided array, as shown in Figure 1. Figure 14 (b) shows a 7×9 braided array. Taking the peripheral series circuit as an example, component 14(a) has a voltage of 5.4 V and a current of 360 mA; component 14(b) has a voltage of 9.6 V and a current of 630 mA. When n and m are not equal, the voltage and current of the warp and weft braided strips are not equal. Due to the characteristic that the parallel voltage and series current are smaller, there are design losses in the circuit. Therefore, the parameter form of n×n is preferred.

[0080] Next, as Figure 15As shown, a schematic diagram of the array mechanical mesh model (4) established in kangaroo is presented. The internal mesh points (43) represent island-type structures (122), and the internal mesh edges (44) represent bridge-type structures. In this example, the stress situation of an 8×8 braided array attached to a hemispherical plane with a diameter of 45mm is simulated. The outer rectangular frame is the initial boundary (41) of the braided circuit, and the circle inscribed in the outer rectangular frame is the target boundary (42) after attachment. Edge constraints, linear damping constraints of the mesh edges, and tension during the attachment process are applied to the model. The ratio of the edge damping of the mesh lines to the applied tension constraint should be consistent with the elastic modulus of the material and the ratio of the maximum tensile force to ensure the reliability of the mechanical model prediction. As shown in 16, for the final optimized mechanical model result, the damping of different mesh lines is changed according to the form of the mechanical model to make the overall surface present a smoother shape, and the deformation is consistent with the actual value of the structure. Based on the optimized braided array parameters, a stretchable flexible braided photovoltaic array is designed.

[0081] Furthermore, the terms "upper," "lower," "inner," "outer," "front," and "rear" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise specifically stated, the relative steps, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0082] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included in the scope of the claims of the present invention.

[0083] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A stretchable flexible woven photovoltaic array, characterized in that, An array is formed by weaving together several strip-shaped battery cells; The strip-shaped battery unit includes a strip-shaped substrate circuit and several photovoltaic devices, wherein the strip-shaped substrate circuit is an FPCB circuit, which includes a flexible substrate and a conductive layer; The strip-shaped battery unit is an island-bridge structure. The island-shaped structure is a photovoltaic device pad, and a photovoltaic device is welded on the top of the photovoltaic device pad. The bridge-shaped structure is a bistable paper-cut structure formed by cutting the strip-shaped substrate circuit to create gaps. The photovoltaic device is an IBC solar cell unit, with a light absorption area on the front and an integer number of alternating positive and negative electrode areas on the back. The method for fabricating the stretchable flexible braided photovoltaic array includes the following steps: (1) Draw the target surface of the stretchable flexible braided photovoltaic array; (2) Determine the braiding array parameters based on the current and voltage parameters, divide the target surface according to the braiding array parameters to obtain the island bridge structure position, connect the island bridge structure positions into warp and weft lines to obtain different flexible braided photovoltaic array design schemes, where the ratio of the length of the bridge structure to the length of the island structure is 1, the ratio of the thickness of the deformed end to the thickness of the fixed end of the bistable paper-cutting structure is 1, and the ratio of the width to the length of the gap in the bistable paper-cutting structure is 0.15; (3) Based on different flexible braided photovoltaic array design schemes, construct array mechanical mesh models, perform mechanical model analysis on the models, and optimize the braided array parameters; (4) Provide a flexible substrate, determine the island bridge structure on the flexible substrate according to the braided array parameters to form a strip battery unit, and braid the strip battery unit into a stretchable flexible braided photovoltaic array by braiding.

2. The flexible woven photovoltaic array according to claim 1, characterized in that, The weaving method includes one or more of biaxial weaving and triaxial weaving.

3. The flexible woven photovoltaic array according to claim 1, characterized in that, The flexible substrate is a polyimide film flexible substrate.

4. The flexible woven photovoltaic array according to claim 1, characterized in that, Photovoltaic devices are connected in parallel to a strip substrate circuit via photovoltaic device pads.

5. The flexible woven photovoltaic array according to claim 1, characterized in that, The size of the IBC solar cell unit is smaller than that of the island structure.

6. The flexible woven photovoltaic array according to claim 1, characterized in that, Each strip battery cell has external solder pads at both ends, which are used to connect the strip battery cells in series or in parallel via soldered wires or pluggable interfaces.

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