Flexible wiring board and method for manufacturing the same

Abstract

In order to overcome the problem of insufficient anti-ultraviolet oxidation ability of the existing flexible circuit board, the application provides a flexible circuit board and a preparation method thereof, the flexible circuit board comprises a flexible plate group, a first insulating adhesive layer, a perovskite wire harness layer, a second insulating adhesive layer and a transparent protective layer, the flexible plate group comprises a plurality of sub-plates and a plurality of third insulating adhesive layers, the sub-plate comprises a flexible substrate and a circuit pattern layer located on at least one side surface of the flexible substrate, a single third insulating adhesive layer is located between two adjacent sub-plates, the first insulating adhesive layer is located on the outer side of the flexible plate group, the perovskite wire harness layer comprises a conductive silver paste layer and a plurality of linear perovskite batteries, the conductive silver paste layer is located on the surface of the first insulating adhesive layer away from the flexible plate group, and a plurality of linear perovskite batteries are arranged in parallel on the conductive silver paste layer.

Description

Technical Field

[0001] This invention belongs to the field of flexible circuit board technology, specifically relating to a flexible circuit board and its preparation method. Background Technology

[0002] With the rapid development of electronic devices towards lightweighting, miniaturization, and bendability, flexible printed circuits (FPCs) have become widely used in consumer electronics, automotive electronics, industrial control, and communication equipment due to their core advantages such as thinness, flexibility, high wiring density, and strong spatial adaptability. In recent years, with the popularization of the Internet of Things (IoT) and smart sensing technologies, the application scenarios of FPCs have further extended to outdoor environments, such as outdoor monitoring sensors, outdoor communication terminals, photovoltaic module terminal blocks, and outdoor display devices. These outdoor application devices need to be exposed to the natural environment for a long time, facing the challenges of complex environmental factors such as sunlight, temperature changes, and humidity fluctuations.

[0003] In outdoor environments, ultraviolet (UV) radiation (wavelength 100-400nm) from sunlight is one of the key causes of FPC (Flexible Printed Circuit) line failure. Existing FPCs primarily use copper foil (including electrolytic copper foil and rolled copper foil) as the conductor, and their surfaces are typically protected only by simple methods such as chemical tin plating, nickel-gold plating, coating with solder resist ink, or covering with a protective film. However, when exposed to UV radiation for extended periods, these protective structures are prone to aging and failure, leading to moisture penetration. UV radiation accelerates the chemical reaction between oxygen and moisture in the air and the copper foil, triggering oxidation and corrosion on the copper foil surface. The copper foil is first oxidized to form cuprous oxide (Cu₂O), and then further oxidized to form copper oxide (CuO). These oxidation products (copper rust) have high resistivity, which significantly increases the circuit's conductivity, exacerbates signal attenuation, and can even lead to faults such as poor contact or open circuits.

[0004] The aforementioned oxidation failure issues directly lead to performance degradation and shortened lifespan of outdoor equipment's FPC: mild oxidation can cause increased power consumption and decreased signal stability, affecting detection accuracy or communication quality; in severe cases, it can lead to complete line failure, causing outdoor equipment to shut down, which not only increases equipment maintenance costs but may also cause greater economic losses due to the loss of critical data or functional interruption.

[0005] Currently, existing technologies for FPC protection mainly focus on improving its mechanical bending performance, high and low temperature resistance, or flame retardant properties. However, there is a lack of targeted solutions for circuit oxidation caused by outdoor ultraviolet radiation. Some solutions improve the insulation effect by increasing the thickness of the protective layer, but this sacrifices the flexibility and bending ability of the FPC, failing to meet the installation and adaptation requirements of outdoor equipment. Other solutions use light-reflective materials as protective films, but these materials are expensive and still cannot completely avoid aging under long-term ultraviolet radiation, resulting in insufficient protection durability.

[0006] Therefore, for outdoor applications, existing flexible printed circuit boards (FPCs) have technical defects such as insufficient resistance to ultraviolet oxidation and easy circuit failure. There is an urgent need for a technical solution that can stably protect the circuit and inhibit oxidation failure under long-term ultraviolet irradiation to meet the requirements of outdoor equipment for FPC reliability and service life. Summary of the Invention

[0007] To address the problem of insufficient resistance to ultraviolet oxidation in existing flexible circuit boards, this invention provides a flexible circuit board and its preparation method.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0009] On one hand, the present invention provides a flexible circuit board, comprising a flexible board assembly, a first insulating adhesive layer, a perovskite wire harness layer, a second insulating adhesive layer, and a transparent protective layer. The flexible board assembly includes multiple sub-boards and multiple third insulating adhesive layers. Each sub-board includes a flexible substrate and a circuit pattern layer located on at least one surface of the flexible substrate. A single third insulating adhesive layer is located between two adjacent sub-boards. The first insulating adhesive layer is located on the outside of the flexible board assembly. The perovskite wire harness layer includes a conductive silver paste layer and multiple linear perovskite cells. The conductive silver paste layer is located on the first insulating adhesive layer away from the surface of the flexible board assembly. The multiple linear perovskite cells are arranged in parallel on the conductive silver paste layer. The second insulating adhesive layer is located on the perovskite wire harness layer away from the surface of the first insulating adhesive layer. The transparent protective layer is located on the second insulating adhesive layer away from the surface of the perovskite wire harness layer.

[0010] Optionally, the conductive silver paste layer covers a portion of the surface of the first insulating adhesive layer and forms a clearance area that does not cover the conductive silver paste layer. The flexible circuit board has a first electrically conductive via and a second electrically conductive via penetrating the flexible circuit board. The first electrically conductive via penetrates the conductive silver paste layer and electrically connects the conductive silver paste layer and at least one of the circuit pattern layers. The second electrically conductive via penetrates the clearance area and electrically connects two or more of the plurality of circuit pattern layers.

[0011] Optionally, the flexible circuit board has a strip structure, the linear perovskite solar cells extend along the length direction of the flexible circuit board, and multiple linear perovskite solar cells are spaced apart along the width direction of the flexible circuit board.

[0012] Optionally, there are multiple conductive silver paste layers, which are spaced apart along the length of the flexible circuit board. Correspondingly, the multiple linear perovskite solar cells include multiple battery packs, which are disposed one-to-one on the multiple conductive silver paste layers. An electrical connection line is provided between two adjacent battery packs to connect them to each other. The electrical connection line is located between the first insulating adhesive layer and the second insulating adhesive layer.

[0013] Optionally, the linear perovskite solar cell includes a metal fiber bundle, an electron transport layer, a perovskite layer, and a hole transport layer. The electron transport layer covers the outer wall of the metal fiber bundle, the perovskite layer covers the outer wall of the electron transport layer, the hole transport layer covers the outer wall of the perovskite layer, and the conductive silver paste layer only covers the surface of the hole transport layer facing the first insulating adhesive layer.

[0014] Optionally, the metal fiber bundle includes one or more of copper fibers, silver fibers, and silver-plated carbon fibers; and / or,

[0015] The electron transport layer comprises SnO2; and / or,

[0016] The perovskite layer comprises one or more of FAPbI3 and FACsPbI3; and / or,

[0017] The hole transport layer includes Spiro-OMeTAD.

[0018] Optionally, the transparent protective layer is selected from a PET layer, and the first insulating adhesive layer, the second insulating adhesive layer, and the third insulating adhesive layer are selected from a polyacrylate adhesive layer.

[0019] Furthermore, the present invention provides a method for fabricating the flexible circuit board as described above, comprising the following steps:

[0020] Step 1: Stack multiple sub-boards in sequence, place a single third insulating adhesive layer between two adjacent sub-boards, and hot press them together to form a flexible board assembly.

[0021] Step 2: Attach a first insulating adhesive layer to one side of the transparent protective layer, and attach multiple linear perovskite cells side by side to the surface of the first insulating adhesive layer away from the transparent protective layer. Apply conductive silver paste to the surface of the multiple linear perovskite cells away from the first insulating adhesive layer and cure it to form a conductive silver paste layer, thus obtaining a flexible battery layer.

[0022] Step 3: Stack the flexible board assembly, the second insulating adhesive layer, and the flexible battery layer in sequence, with the conductive silver paste layer of the flexible battery layer facing the second insulating adhesive layer, and perform hot pressing to obtain a flexible circuit board.

[0023] Optionally, in step 2, the conductive silver paste layer is coated on a portion of the surface of the first insulating adhesive layer, forming a clearance area that does not cover the conductive silver paste layer.

[0024] The method also includes step 4: drilling and metallizing the area corresponding to the conductive silver paste layer and the avoidance area on the flexible circuit board to obtain a first electrically conductive via and a second electrically conductive via. The first electrically conductive via penetrates the conductive silver paste layer and electrically connects the conductive silver paste layer and at least one of the circuit pattern layers. The second electrically conductive via penetrates the avoidance area and electrically connects two or more of the multiple circuit pattern layers.

[0025] Optionally, the linear perovskite solar cell is prepared by the following method:

[0026] The metal fiber bundle is vertically immersed in SnO2 solution and slowly pulled up to form a uniform SnO2 film on the surface of the metal fiber bundle. After drying, an electron transport layer is obtained.

[0027] The metal fiber bundle with the electron transport layer is then vertically immersed into the perovskite precursor solution and slowly pulled out to form a wet precursor film. The film is then heated and annealed to obtain the perovskite layer.

[0028] The metal fiber bundle with the perovskite layer is then vertically immersed in the Spiro-OMeTAD solution, slowly pulled out, and dried to form a hole transport layer.

[0029] According to the flexible circuit board provided by this invention, a perovskite wire harness layer is integrated with a flexible board assembly. The perovskite wire harness layer includes a conductive silver paste layer and multiple linear perovskite cells. These linear perovskite cells have a high absorption coefficient for ultraviolet light, converting ultraviolet energy into electrical energy instead of allowing ultraviolet light to penetrate to the flexible board assembly below. Simultaneously, a transparent protective layer blocks some short-wave ultraviolet light, forming double protection and preventing oxidation of the circuit pattern layer. After absorbing ultraviolet and visible light, the linear perovskite cells in the perovskite wire harness layer achieve photoelectric conversion through an electron transport layer and a hole transport layer. The generated electrical energy is conducted through the conductive silver paste layer to power the circuit pattern layer or for storage in an external battery, solving the power supply problem for outdoor equipment. Furthermore, compared to traditional planar perovskite cells, the linear perovskite cells are flexible and can adapt to the flexible bending function of the flexible circuit board, ensuring that the overall structure can bend synchronously with the flexible board assembly, avoiding any impact on the bending function of the flexible circuit board. Attached Figure Description

[0030] Figure 1 This is a cross-sectional schematic diagram of the flexible circuit board provided by the present invention;

[0031] Figure 2 This is a planar schematic diagram of the flexible circuit board provided by the present invention;

[0032] Figure 3 This is a cross-sectional schematic diagram of the linear perovskite solar cell provided by the present invention.

[0033] The reference numerals in the accompanying drawings are as follows:

[0034] 1. Flexible board assembly; 11. Sub-board; 111. Flexible substrate; 112. Circuit pattern layer; 12. Third insulating adhesive layer; 2. First insulating adhesive layer; 21. Clearance area; 3. Perovskite wire bundle layer; 31. Conductive silver paste layer; 32. Linear perovskite cell; 321. Metal fiber bundle; 322. Electron transport layer; 323. Perovskite layer; 324. Hole transport layer; 33. Electrical connection wire; 4. Second insulating adhesive layer; 5. Transparent protective layer; 6. First electrical via; 7. Second electrical via. Detailed Implementation

[0035] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0036] See Figure 1 As shown, an embodiment of the present invention provides a flexible circuit board, including a flexible board assembly 1, a first insulating adhesive layer 2, a perovskite wire harness layer 3, a second insulating adhesive layer 4, and a transparent protective layer 5. The flexible board assembly 1 includes a plurality of sub-boards 11 and a plurality of third insulating adhesive layers 12. Each sub-board 11 includes a flexible substrate 111 and a circuit pattern layer 112 located on at least one surface of the flexible substrate 111. A single third insulating adhesive layer 12 is located between two adjacent sub-boards 11. The first insulating adhesive layer 2 is located on the flexible board assembly 11. On the outer side of the board assembly 1, the perovskite wire harness layer 3 includes a conductive silver paste layer 31 and a plurality of linear perovskite cells 32. The conductive silver paste layer 31 is located on the first insulating adhesive layer 2 away from the surface of the flexible board assembly 1. The plurality of linear perovskite cells 32 are arranged in parallel on the conductive silver paste layer 31. The second insulating adhesive layer 4 is located on the perovskite wire harness layer 3 away from the surface of the first insulating adhesive layer 2. The transparent protective layer 5 is located on the second insulating adhesive layer 4 away from the surface of the perovskite wire harness layer 3.

[0037] The flexible circuit board integrates the perovskite wiring layer 3 with the flexible board assembly 1. The perovskite wiring layer 3 includes a conductive silver paste layer 31 and multiple linear perovskite cells 32. The linear perovskite cells 32 have a high absorption coefficient for ultraviolet light, converting ultraviolet energy into electrical energy instead of allowing ultraviolet light to penetrate to the flexible board assembly 1 below. Simultaneously, the transparent protective layer 5 blocks some short-wave ultraviolet light, forming double protection to prevent oxidation of the circuit pattern layer 112. After absorbing ultraviolet and visible light, the linear perovskite cells 32 in the perovskite wiring layer 3 achieve photoelectric conversion through the electron transport layer 322 and hole transport layer 324. The generated electrical energy is conducted through the conductive silver paste layer 31 to power the circuit pattern layer 112 or for storage in an external battery, solving the power supply problem for outdoor equipment. Furthermore, compared to traditional planar perovskite cells, the linear perovskite cells 32 are flexible and can adapt to the flexible bending function of the flexible circuit board, ensuring that the overall structure can bend synchronously with the flexible board assembly 1, avoiding any impact on the bending function of the flexible circuit board.

[0038] In some embodiments, the number of sub-boards 11 in the flexible board assembly 1 is 2 to 5; the circuit pattern layer 112 is prepared by electrolytic copper foil or rolled copper foil with a copper foil thickness of 12 to 35 μm, and then the circuit pattern layer 112 is prepared by etching through exposure and development. The surface of the circuit pattern layer 112 is micro-etched to form a microstructure with a roughness Ra of 0.3 to 0.8 μm, which enhances the bonding force with the flexible substrate 111 and the third insulating adhesive layer 12.

[0039] In some embodiments, the diameter of the linear perovskite solar cell 32 is 50-500 μm, and the spacing between adjacent linear perovskite solar cells 32 is 20-500 μm; the thickness of the conductive silver paste layer 31 is 10-30 μm, and a low-temperature curing silver paste (curing temperature ≤120℃) is used.

[0040] In some embodiments, the thickness of the first insulating adhesive layer 2 and the second insulating adhesive layer 4 is 10-300 μm, and the thickness of the third insulating adhesive layer 12 is 8-15 μm.

[0041] In some embodiments, the conductive silver paste layer 31 covers a portion of the surface of the first insulating adhesive layer 2 and forms a clearance area 21 that does not cover the conductive silver paste layer 31. The flexible circuit board has a first electrically conductive via 6 and a second electrically conductive via 7 penetrating the flexible circuit board. The first electrically conductive via 6 penetrates the conductive silver paste layer 31 and electrically connects the conductive silver paste layer 31 and at least one of the circuit pattern layers 112. The second electrically conductive via 7 penetrates the clearance area 21 and electrically connects two or more of the plurality of circuit pattern layers 112.

[0042] The first via 6 is specifically used to connect the conductive silver paste layer 31 and the circuit pattern layer 112, and to conduct the electrical energy generated by the perovskite solar cell in a directional manner. The avoidance area 21 of the conductive silver paste layer 31 is a reserved channel for the connection between the circuit pattern layers 112. When the second via 7 passes through the avoidance area 21, it will not short-circuit with the conductive silver paste layer 31, so as to realize the flexible conduction of the circuit pattern layers 112 of multiple sub-boards 11. Through the partition design of the two types of vias, the independent and reliable connection between the perovskite power generation layer and the circuit layer, and between the circuit layers, is realized.

[0043] In some embodiments, the number of the first conductive via 6 and the second conductive via 7 are both multiple.

[0044] In some embodiments, the conductive silver paste layer 31 covers an area of ​​60%-80% of the surface area of ​​the first insulating adhesive layer 2.

[0045] In some embodiments, the flexible circuit board is a strip structure, the linear perovskite solar cell 32 extends along the length direction of the flexible circuit board, and a plurality of the linear perovskite solar cells 32 are spaced apart along the width direction of the flexible circuit board.

[0046] Strip-shaped flexible circuit boards are typically bent in a direction perpendicular to their length. Linear perovskite solar cells 32, on the other hand, have good bendability in a direction perpendicular to their length. Extending the linear perovskite solar cells 32 along the length of the flexible circuit board helps ensure the consistency of their bendability. During bending, the tensile deformation of the linear perovskite solar cells 32 is evenly distributed. Combined with the spaced design to reserve deformation space, this avoids bending failure of the flexible circuit board due to the rigidity of the cell layer.

[0047] In some embodiments, the number of linear perovskite solar cells 32 arranged along the width direction of the flexible circuit board is 3-10.

[0048] like Figure 2 As shown, in some embodiments, there are multiple conductive silver paste layers 31, which are spaced apart along the length of the flexible circuit board. Correspondingly, the multiple linear perovskite solar cells 32 include multiple battery packs, which are disposed one-to-one on the multiple conductive silver paste layers 31. An electrical connection line 33 is provided between two adjacent battery packs to connect them to each other. The electrical connection line 33 is located between the first insulating adhesive layer 2 and the second insulating adhesive layer 4.

[0049] By arranging multiple battery packs at intervals along the length of the flexible circuit board, the spacing between adjacent battery packs provides greater bending flexibility, which helps ensure that the flexible circuit board can still meet some large-angle bending requirements for outdoor installation.

[0050] Since the multiple linear perovskite cells 32 in a single battery pack are all located on the same conductive silver paste layer 31, the parallel arrangement of multiple linear perovskite cells 32 in a single battery pack can be achieved by connecting two adjacent battery packs in series or in parallel through the electrical connection line 33.

[0051] like Figure 3 As shown, in some embodiments, the linear perovskite solar cell 32 includes a metal fiber bundle 321, an electron transport layer 322, a perovskite layer 323, and a hole transport layer 324. The electron transport layer 322 covers the outer wall of the metal fiber bundle 321, the perovskite layer 323 covers the outer wall of the electron transport layer 322, the hole transport layer 324 covers the outer wall of the perovskite layer 323, and the conductive silver paste layer 31 only covers the surface of the hole transport layer 324 facing the first insulating adhesive layer 2.

[0052] The linear perovskite solar cell 32 has a metal fiber bundle 321 as its core and has good flexibility. The metal fiber bundle 321, electron transport layer 322, perovskite layer 323 and hole transport layer 324 have good adhesion, which can ensure the overall flexibility of the linear perovskite solar cell 32.

[0053] The conductive silver paste layer 31 is used to collect the current generated by the hole transport layer 324. It only covers the surface of the hole transport layer 324 facing the first insulating adhesive layer 2. While ensuring a good contact area with the hole transport layer 324, it can avoid blocking the light-receiving surface of the linear perovskite solar cell 32.

[0054] At the same time, such as Figure 3 As shown, the linear perovskite solar cell 32 has a cylindrical structure, and the electron transport layer 322, perovskite layer 323, and hole transport layer 324 are all transparent. The conductive silver paste layer 31 forms a structure similar to a reflector on the outer wall of the linear perovskite solar cell 32. Light that is not absorbed after penetrating the electron transport layer 322, perovskite layer 323, and hole transport layer 324 can be reflected back to the perovskite layer 323 through the conductive silver paste layer 31, thereby effectively improving the photoelectric conversion efficiency of the linear perovskite solar cell 32.

[0055] In some embodiments, the metal fiber bundle 321 is formed by twisting together 5-10 metal fibers with a single filament diameter of 5-20 μm.

[0056] In some embodiments, the metal fiber bundle 321 includes one or more of copper fibers, silver fibers, and silver-plated carbon fibers.

[0057] In some embodiments, the electron transport layer 322 comprises SnO2.

[0058] In some embodiments, the perovskite layer 323 includes one or more of FAPbI3 and FACsPbI3.

[0059] In some embodiments, the hole transport layer 324 includes Spiro-OMeTAD.

[0060] In some embodiments, the transparent protective layer 5 is selected from a PET layer, and the first insulating adhesive layer 2, the second insulating adhesive layer 4 and the third insulating adhesive layer 12 are selected from a polyacrylate adhesive layer.

[0061] PET material has a light transmittance of over 90%, which does not affect the absorption of ultraviolet rays by the perovskite layer 323; and PET is not prone to yellowing or embrittlement under ultraviolet irradiation.

[0062] The polyacrylate adhesive layer has high bonding strength, good flexibility and weather resistance, and can maintain stable bonding in an outdoor temperature range of -40℃ to 85℃, avoiding interlayer delamination; at the same time, it has strong compatibility with the flexible substrate 111, PET layer and conductive silver paste layer 31, and will not undergo chemical reaction, ensuring long-term structural stability.

[0063] Another aspect of the present invention provides a method for fabricating the flexible circuit board as described above, comprising the following steps:

[0064] Step 1: Stack multiple sub-boards 11 in sequence, place a single third insulating adhesive layer 12 between two adjacent sub-boards 11, and perform hot pressing to bond them together to form a flexible board assembly 1.

[0065] Step 2: Attach the first insulating adhesive layer 2 to one side of the transparent protective layer 5, and attach multiple linear perovskite cells 32 side by side to the surface of the first insulating adhesive layer 2 away from the transparent protective layer 5. Apply conductive silver paste to the surface of the multiple linear perovskite cells 32 away from the first insulating adhesive layer and cure it to form a conductive silver paste layer 31, thus obtaining a flexible battery layer.

[0066] Step 3: The flexible board assembly 1, the second insulating adhesive layer 4 and the flexible battery layer are stacked in sequence, with the conductive silver paste layer 31 of the flexible battery layer facing the second insulating adhesive layer 4, and then hot-pressed to obtain a flexible circuit board.

[0067] Using the above preparation method, the flexible board assembly 1 and the flexible battery layer can be combined to form an integral flexible circuit board that can be flexibly bent.

[0068] In some embodiments, in step 3, the temperature of the hot pressing operation is 80°C to 120°C, which is lower than the thermal decomposition temperature of the perovskite layer 323, so as to avoid performance failure of the perovskite layer 323.

[0069] In some embodiments, in step 2, the conductive silver paste layer 31 is coated on a portion of the surface of the first insulating adhesive layer 2, and a clearance area 21 is formed that does not cover the conductive silver paste layer 31.

[0070] The method also includes step 4: drilling and metallizing the area corresponding to the conductive silver paste layer 31 and the avoidance area 21 on the flexible circuit board to obtain a first electrically conductive via 6 and a second electrically conductive via 7. The first electrically conductive via 6 penetrates the conductive silver paste layer 31 and electrically connects the conductive silver paste layer 31 and at least one of the circuit pattern layers 112. The second electrically conductive via 7 penetrates the avoidance area 21 and electrically connects two or more of the plurality of circuit pattern layers 112.

[0071] Drilling is performed after the overall stacking and hot pressing, which can accurately locate the conductive silver paste layer 31 area and the avoidance area 21, avoiding interlayer misalignment caused by pre-drilling; the metallization process (such as chemical copper plating) can form a uniform conductive layer on the inner wall of the through hole, ensuring that the first electrically conductive through hole 6 achieves effective conduction between the conductive silver paste layer 31 and the circuit pattern layer 112, and the second electrically conductive through hole 7 achieves reliable connection between the circuit layers, and the metallization layer has strong bonding force with each layer, and will not fall off due to bending or outdoor environment.

[0072] In some embodiments, in step 4, the drilling process uses laser drilling, and after drilling, plasma cleaning is used to remove the residue from the hole wall.

[0073] In some embodiments, the linear perovskite solar cell 32 is prepared by the following method:

[0074] The metal fiber bundle 321 is vertically immersed in the SnO2 solution and slowly pulled up to form a uniform SnO2 film on the surface of the metal fiber bundle 321. After drying, the electron transport layer 322 is obtained.

[0075] The metal fiber bundle 321 with the electron transport layer 322 is then vertically immersed into the perovskite precursor solution and slowly pulled out to form a wet precursor film. The perovskite layer 323 is obtained by heating and annealing.

[0076] The metal fiber bundle 321 with the perovskite layer 323 is then vertically immersed in the Spiro-OMeTAD solution, slowly pulled out, and dried to form the hole transport layer 324.

[0077] In the vertical immersion method for electron transport layer 322, perovskite layer 323, and hole transport layer 324, metal fiber bundle 321 is vertically immersed in the solution. When slowly pulled up, the solution forms a uniform wet film on the surface of metal fiber bundle 321. The film thickness can be precisely controlled by the pulling speed (usually 1-5 mm / s). In some embodiments, to achieve the target thickness and ensure film thickness uniformity, the immersion, pulling up, and drying operations can be repeated to avoid differences in charge transport efficiency caused by uneven film thickness. The layered coating process ensures that electron transport layer 322, perovskite layer 323, and hole transport layer 324 are sequentially and tightly coated on the surface of metal fiber bundle 321, with tight interlayer bonding, avoiding interlayer delamination caused by outdoor environment. At the same time, the uniform thin film layer can reduce stress concentration, ensuring that the battery layer does not crack when the flexible circuit board is bent, maintaining the stability of flexibility and power generation function.

[0078] Annealing can promote the crystallization of perovskite precursors, forming a dense and uniform perovskite layer 323, thereby improving ultraviolet absorption and photoelectric conversion efficiency.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible circuit board, characterized in that, The system comprises a flexible board assembly, a first insulating adhesive layer, a perovskite wire harness layer, a second insulating adhesive layer, and a transparent protective layer. The flexible board assembly includes multiple sub-boards and multiple third insulating adhesive layers. Each sub-board includes a flexible substrate and a circuit pattern layer located on at least one surface of the flexible substrate. A single third insulating adhesive layer is located between two adjacent sub-boards. The first insulating adhesive layer is located on the outside of the flexible board assembly. The perovskite wire harness layer includes a conductive silver paste layer and multiple linear perovskite cells. The conductive silver paste layer is located on the first insulating adhesive layer and faces away from the surface of the flexible board assembly. The multiple linear perovskite cells are arranged in parallel on the conductive silver paste layer. The second insulating adhesive layer is located on the perovskite wire harness layer and faces away from the surface of the first insulating adhesive layer. The transparent protective layer is located on the second insulating adhesive layer and faces away from the surface of the perovskite wire harness layer. The conductive silver paste layer covers a portion of the surface of the first insulating adhesive layer and forms a clearance area that does not cover the conductive silver paste layer. The flexible circuit board has a first electrical through-hole and a second electrical through-hole that penetrate the flexible circuit board. The first electrical through-hole penetrates the conductive silver paste layer and electrically connects the conductive silver paste layer and at least one of the circuit pattern layers. The second electrical through-hole penetrates the clearance area and electrically connects two or more of the multiple circuit pattern layers.

2. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board has a strip structure, the linear perovskite solar cells extend along the length of the flexible circuit board, and multiple linear perovskite solar cells are spaced apart along the width of the flexible circuit board.

3. The flexible circuit board according to claim 2, characterized in that, The number of conductive silver paste layers is multiple, and the multiple conductive silver paste layers are spaced apart along the length direction of the flexible circuit board. Correspondingly, the multiple linear perovskite solar cells include multiple battery packs, and the multiple battery packs are disposed one-to-one on the multiple conductive silver paste layers. An electrical connection line is provided between two adjacent battery packs to connect them to each other. The electrical connection line is located between the first insulating adhesive layer and the second insulating adhesive layer.

4. The flexible circuit board according to claim 1, characterized in that, The linear perovskite solar cell includes a metal fiber bundle, an electron transport layer, a perovskite layer, and a hole transport layer. The electron transport layer covers the outer wall of the metal fiber bundle, the perovskite layer covers the outer wall of the electron transport layer, the hole transport layer covers the outer wall of the perovskite layer, and the conductive silver paste layer only covers the surface of the hole transport layer facing the first insulating adhesive layer.

5. The flexible circuit board according to claim 4, characterized in that, The metal fiber bundle includes one or more of copper fibers, silver fibers, and silver-plated carbon fibers; and / or, The electron transport layer comprises SnO2; and / or, The perovskite layer comprises one or more of FAPbI3 and FACsPbI3; and / or, The hole transport layer includes Spiro-OMeTAD.

6. The flexible circuit board according to claim 1, characterized in that, The transparent protective layer is selected from PET layer, and the first insulating adhesive layer, the second insulating adhesive layer and the third insulating adhesive layer are selected from polyacrylate adhesive layer.

7. The method for preparing a flexible circuit board according to any one of claims 1 to 6, characterized in that, The following steps are included: Step 1: Stack multiple sub-boards in sequence, place a single third insulating adhesive layer between two adjacent sub-boards, and hot press them together to form a flexible board assembly. Step 2: Attach a first insulating adhesive layer to one side of the transparent protective layer, and attach multiple linear perovskite cells side by side to the surface of the first insulating adhesive layer away from the transparent protective layer. Apply conductive silver paste to the surface of the multiple linear perovskite cells away from the first insulating adhesive layer and cure it to form a conductive silver paste layer, thus obtaining a flexible battery layer. Step 3: Stack the flexible board assembly, the second insulating adhesive layer, and the flexible battery layer in sequence, with the conductive silver paste layer of the flexible battery layer facing the second insulating adhesive layer, and perform hot pressing to obtain a flexible circuit board.

8. The method for preparing a flexible circuit board according to claim 7, characterized in that, In step 2, the conductive silver paste layer is coated on a portion of the surface of the first insulating adhesive layer, forming a clearance area that does not cover the conductive silver paste layer. The method also includes step 4: drilling and metallizing the area corresponding to the conductive silver paste layer and the avoidance area on the flexible circuit board to obtain a first electrically conductive via and a second electrically conductive via. The first electrically conductive via penetrates the conductive silver paste layer and electrically connects the conductive silver paste layer and at least one of the circuit pattern layers. The second electrically conductive via penetrates the avoidance area and electrically connects two or more of the multiple circuit pattern layers.

9. The method for preparing a flexible circuit board according to claim 7, characterized in that, The linear perovskite solar cell was prepared by the following method: The metal fiber bundle is vertically immersed in SnO2 solution and slowly pulled up to form a uniform SnO2 film on the surface of the metal fiber bundle. After drying, an electron transport layer is obtained. The metal fiber bundle with the electron transport layer is then vertically immersed into the perovskite precursor solution and slowly pulled out to form a wet precursor film. The film is then heated and annealed to obtain the perovskite layer. The metal fiber bundle with the perovskite layer is then vertically immersed in the Spiro-OMeTAD solution, slowly pulled out, and dried to form a hole transport layer.

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