Portable bifacial photovoltaic module and method of manufacturing the same

Abstract

The application discloses a portable double-sided photovoltaic module and a preparation method thereof, and relates to the technical field of photovoltaic power generation. The portable double-sided photovoltaic module comprises a front plate, a waterproof back plate arranged opposite to the front plate, a front power generation unit arranged between the front plate and the waterproof back plate, a back power generation unit arranged between the front power generation unit and the waterproof back plate, and a plurality of crystalline silicon cell pieces connected in series to form a crystalline silicon cell group. The back power generation unit comprises a plurality of perovskite sub-cell pieces connected in series to form a perovskite cell group. The crystalline silicon cell group and the perovskite cell group are connected in parallel. The ratio of the number of series connections of the crystalline silicon cell pieces contained in the crystalline silicon cell group to the number of series connections of the perovskite sub-cell pieces contained in the perovskite cell group is configured according to the ratio of the open-circuit voltage of the crystalline silicon cell piece to the open-circuit voltage of the perovskite sub-cell piece. The application improves the overall output power of the portable double-sided photovoltaic module and the power generation performance in actual use scenarios.

Description

Technical Field

[0001] This application relates to the field of photovoltaic power generation technology, specifically to a portable bifacial photovoltaic module and its preparation method. Background Technology

[0002] One related technology involves stacking perovskite and crystalline silicon solar cells to form a tandem solar cell. By integrating a perovskite coating onto the crystalline silicon cell, the perovskite absorbs high-energy short-wavelength light, while the crystalline silicon absorbs long-wavelength light, achieving complementary absorption spectra. However, the open-circuit voltages of crystalline silicon and perovskite cells differ. If they are directly connected in series, the overall output of the tandem solar cell is limited by the smaller current due to current matching constraints, resulting in efficiency loss. If they are simply connected in parallel, voltage mismatch will cause circulating current losses, which may even damage the cells in severe cases.

[0003] Therefore, how to design a portable bifacial photovoltaic module that has both bifacial photoelectric conversion capability and can solve the voltage mismatch problem between crystalline silicon cells and perovskite cells has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] This application aims to at least address the problems existing in related technologies, such as the inability to generate electricity from the back of photovoltaic modules and the voltage mismatch between crystalline silicon cells and perovskite cells.

[0005] To this end, the first aspect of this application provides a portable bifacial photovoltaic module, comprising: a front panel; a waterproof back panel disposed opposite to the front panel; a front power generation unit disposed between the front panel and the waterproof back panel, the front power generation unit comprising a crystalline silicon cell array formed by multiple crystalline silicon cells connected in series; a rear power generation unit disposed between the front power generation unit and the waterproof back panel, the rear power generation unit comprising a perovskite cell array formed by multiple perovskite sub-cells connected in series; the crystalline silicon cell array and the perovskite cell array are connected in parallel, and the ratio of the number of crystalline silicon cells in the crystalline silicon cell array to the number of perovskite sub-cells in the perovskite cell array is configured according to the ratio of the open-circuit voltage of the crystalline silicon cells to the open-circuit voltage of the perovskite sub-cells, so as to match the output voltage of the crystalline silicon cell array with the output voltage of the perovskite cell array.

[0006] The portable bifacial photovoltaic module according to this application includes a front panel, a waterproof backsheet, a front power generation unit, and a rear power generation unit. The front panel and the waterproof backsheet are arranged opposite each other, and the front power generation unit is disposed between the front panel and the waterproof backsheet. The front power generation unit includes a crystalline silicon cell array, which is formed by multiple crystalline silicon cells connected in series. The rear power generation unit is disposed between the front power generation unit and the waterproof backsheet, and the rear power generation unit includes a perovskite cell array, which is formed by multiple perovskite sub-cells connected in series. The crystalline silicon cell array and the perovskite cell array are connected in parallel. There is a ratio between the number of crystalline silicon cells in the crystalline silicon cell array and the number of perovskite sub-cells in the perovskite cell array, and this ratio is configured according to the ratio of the open-circuit voltage of the crystalline silicon cell array to the open-circuit voltage of the perovskite sub-cells, so that the output voltage of the crystalline silicon cell array matches the output voltage of the perovskite cell array. The front panel serves as a front protective layer, allowing sunlight to pass through the front panel and reach the front power generation unit. A waterproof backsheet is located on the back of the portable bifacial photovoltaic module, preventing external moisture from entering the module from the back. The crystalline silicon cells in the front-side power generation unit absorb sunlight transmitted through the front panel and convert it into electricity. The perovskite sub-cells in the rear-side power generation unit absorb light incident from the waterproof backsheet side, including reflected light from the ground and scattered light from the surrounding environment, and convert this light energy into electricity.

[0007] Since the crystalline silicon and perovskite solar cells are respectively located on the front and back sides of the module, each group of cells independently receives light and performs photoelectric conversion. The output voltage of the crystalline silicon solar cell group is determined by the number of crystalline silicon cells connected in series and the open-circuit voltage of each crystalline silicon cell. The output voltage of the perovskite solar cell group is determined by the number of perovskite sub-cells connected in series and the open-circuit voltage of each perovskite sub-cell. By configuring the ratio of the number of cells in series according to the ratio of the open-circuit voltages of the two types of cells, it is possible to ensure that the two groups of cells output approximately equal voltages when operating independently. When the two groups of cells are connected in parallel, since the output voltages are already matched, there will be no circulating current loss between the two groups of cells due to voltage differences. Parallel connection allows the two groups of cells to operate at different current output levels without mutual restriction due to current differences. Therefore, the portable bifacial photovoltaic module of this application has bifacial power generation capability, and can generate electricity simultaneously by utilizing direct sunlight on the front side and diffused and reflected light on the back side, thereby improving the light energy utilization rate per unit area. Crystalline silicon and perovskite solar cells are located on the front and back sides of the portable bifacial photovoltaic module, respectively, each performing photoelectric conversion independently. The two groups of cells are connected in parallel. By configuring the series ratio based on the open-circuit voltage ratio, the output voltages of the two groups of cells are matched, avoiding circulating current losses caused by voltage mismatch in simple parallel connection, and also avoiding efficiency losses due to current limitations in direct series connection. Without increasing the overall area, this application increases the total power generation by adding rear-side power generation units, improving the overall output power of the portable bifacial photovoltaic module and its power generation performance in practical application scenarios.

[0008] In some embodiments, optionally, the perovskite solar cell pack includes: a first conductive layer disposed on the side of the waterproof backplate facing the front power generation unit; a perovskite light absorption layer disposed on the side of the first conductive layer facing the front power generation unit; and a second conductive layer disposed on the side of the perovskite light absorption layer facing the front power generation unit; wherein the perovskite light absorption layer is divided into a plurality of perovskite sub-cells spaced apart along a first direction by laser etching, and adjacent perovskite sub-cells are connected in series with the first conductive layer through the second conductive layer.

[0009] In this way, by dividing the large-area perovskite light-absorbing layer into multiple sub-cells and connecting them in series through laser etching, it is possible to ensure that the perovskite solar cell pack has a high output voltage while meeting the voltage matching requirements with crystalline silicon solar cell packs. The waterproof backsheet directly supports the perovskite solar cell pack and provides a moisture barrier for the perovskite material, thereby mitigating the performance degradation problem caused by moisture intrusion of the perovskite material and improving the service life of portable bifacial photovoltaic modules.

[0010] Optionally, the first conductive layer and the second conductive layer are made of transparent conductive materials, so that light can pass through the first conductive layer and the second conductive layer to reach the perovskite light absorption layer, and at the same time, light incident from the waterproof backing side can also enter the perovskite light absorption layer and be absorbed and utilized.

[0011] In some embodiments, optionally, a plurality of isolation trenches are provided on the perovskite light-absorbing layer at intervals, the plurality of isolation trenches dividing the perovskite light-absorbing layer into a plurality of perovskite sub-cells arranged at intervals along a first direction; the isolation trenches include a first etching trench and a second etching trench arranged adjacent to each other, the first etching trench penetrating the perovskite light-absorbing layer and exposing a first conductive layer, and the second etching trench penetrating the first conductive layer and the perovskite light-absorbing layer.

[0012] Thus, the isolation groove helps the perovskite solar cell to obtain a higher output voltage, and at the same time helps to match the output voltage of the perovskite solar cell with that of the crystalline silicon solar cell.

[0013] In some embodiments, optionally, the first etching tank includes an insulating portion and a conductive connection channel, the conductive connection channel being located between the insulating portion and the second etching tank; the insulating portion of the first etching tank is filled with a first insulating layer, and the second etching tank is filled with a second insulating layer; the perovskite solar cell further includes a conductive connection layer, the conductive connection channel being filled with a conductive connection layer, the conductive connection layer connecting the second conductive layer of one perovskite sub-cell and the first conductive layer of an adjacent perovskite sub-cell in series; the perovskite solar cell further includes a plurality of third etching tanks, the third etching tanks being located on the side of the first etching tank away from the first conductive layer, and the third etching tanks penetrating the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells.

[0014] Thus, through the cooperation of the first, second, and third etching tanks, multiple perovskite sub-cells form a perovskite solar cell array connected in series. This application, by adjusting the number of perovskite sub-cells connected in series, enables the output voltage of the perovskite solar cell array to match that of the crystalline silicon solar cell array. Simultaneously, the insulating and conductive materials filled in the first and second etching tanks help reduce resistance losses in the series connection region, thereby improving the overall photoelectric conversion efficiency.

[0015] Optionally, one of the bottom electrode and the top electrode is a positive electrode, and the other is a negative electrode.

[0016] In some embodiments, optionally, the number N of the perovskite sub-cells connected in series and the number M of the crystalline silicon cells connected in series satisfy the following:

[0017] ;

[0018] in, This represents the open-circuit voltage of a single crystalline silicon solar cell. The open-circuit voltage of a single perovskite subcell is represented by α, which represents the compensation coefficient, and α is greater than or equal to 0.9 and less than or equal to 1.1.

[0019] Thus, this application constructs a precise matching relationship between the series ratio of crystalline silicon solar cells and perovskite solar cells and the open-circuit voltage ratio through the above formula, and introduces a compensation coefficient α to reserve adjustment margin for engineering deviations, so that the two sets of cells can still maintain basic matching of output voltage under the conditions of operating temperature changes and batch production errors, fundamentally eliminating circulating current losses caused by voltage mismatch.

[0020] Optionally, the open-circuit voltage of a single crystalline silicon solar cell is 0.71V, the open-circuit voltage of a single perovskite sub-cell is 1.1V; and / or the ratio of the number of perovskite sub-cells connected in series to the number of crystalline silicon solar cells connected in series is 6:10.

[0021] In this way, by configuring the number of perovskite sub-cells in series with the number of crystalline silicon cells in series at a ratio of 6:10, the total output voltage of the perovskite cell pack is basically the same as that of the crystalline silicon cell pack. This avoids circulating current losses between the two sets of cells due to voltage differences, and also avoids efficiency losses caused by current limitations when the two sets of cells are directly connected in series.

[0022] Optionally, the water vapor transmission rate of the waterproof backsheet is less than or equal to 6 × 10⁻⁶. -5 g / (m 2 ·day).

[0023] In this way, the waterproof backsheet is also light-transmitting, allowing light to pass through the waterproof backsheet and reach the perovskite light-absorbing layer. This enables the perovskite solar cell to generate electricity using light incident from the back of the portable bifacial photovoltaic module, while also improving the overall output power and lifespan of the portable bifacial photovoltaic module.

[0024] In some embodiments, the portable bifacial photovoltaic module may optionally include: a first encapsulating film disposed between the front panel and the front power generation unit; and a second encapsulating film disposed between the front power generation unit and the rear power generation unit.

[0025] Thus, the first and second encapsulating films have high light transmittance, which facilitates light transmission to the front and back power generation units, reducing optical losses. After cross-linking and curing, the first and second encapsulating films form a dense encapsulation layer, which helps improve the overall structural stability and sealing performance of portable bifacial photovoltaic modules.

[0026] Optionally, both the first and second films are ultra-low temperature cross-linked POE (Polyolefin Elastomer) films, which can reduce the lamination and encapsulation temperature to 120℃±5℃, avoiding thermal damage to the perovskite light absorption layer caused by traditional lamination and encapsulation temperatures.

[0027] In some embodiments, the front panel may optionally include a PET (Polyethylene Terephthalate) substrate and a fluorinated coating, wherein the fluorinated coating is disposed on the surface of the PET substrate opposite to the waterproof back panel; the thickness of the front panel is greater than or equal to 0.3 mm and less than or equal to 0.6 mm.

[0028] Thus, the fluorinated coating is hydrophobic, which reduces the amount of dust and contaminants adhering to the front panel surface. The fluorinated coating also resists UV radiation damage to the PET substrate, slowing down its aging during outdoor use.

[0029] The thickness of the front panel is greater than or equal to 0.3 mm and less than or equal to 0.6 mm, giving the front panel sufficient mechanical strength to support the front and rear power generation units, while maintaining the flexibility and lightweight of the portable bifacial photovoltaic module.

[0030] Based on the same technical concept, the second aspect of this application provides a method for fabricating a portable bifacial photovoltaic module, used to fabricate the portable bifacial photovoltaic module as proposed in the first aspect. The method for fabricating the portable bifacial photovoltaic module includes: obtaining a front panel, a waterproof backsheet, crystalline silicon solar cells, and a perovskite solar cell array; connecting the crystalline silicon solar cells in series by soldering ribbons to form a crystalline silicon solar cell array; determining the number of perovskite sub-cells to be connected in series based on the output voltage of the crystalline silicon solar cell array; dividing the perovskite solar cell array into multiple perovskite sub-cells by laser etching, and connecting the multiple perovskite sub-cells in series; connecting the output terminals of the crystalline silicon solar cell array and the output terminals of the perovskite solar cell array in parallel; stacking the front panel, a first encapsulant film, the crystalline silicon solar cell array, a second encapsulant film, the perovskite solar cell array, and the waterproof backsheet in sequence to form a laminated structure; and laminating and encapsulating the laminated structure to obtain the portable bifacial photovoltaic module.

[0031] According to the method for fabricating a portable bifacial photovoltaic module proposed in this application, a front panel, a waterproof backsheet, crystalline silicon solar cells, and a perovskite solar cell array are obtained as starting materials. Crystalline silicon solar cells are connected in series with solder ribbons to form a crystalline silicon solar cell array. This series welding superimposes the voltages of multiple crystalline silicon solar cells, and the output voltage of the crystalline silicon solar cell array is determined by the number of crystalline silicon solar cells connected in series and the open-circuit voltage of each individual crystalline silicon solar cell. The number of perovskite sub-cells connected in series is determined based on the output voltage of the crystalline silicon solar cell array, ensuring that the output voltage of the perovskite solar cell array matches that of the crystalline silicon solar cell array. Laser etching divides the entire perovskite solar cell array into multiple perovskite sub-cells. These divided perovskite sub-cells are then connected in series with conductive materials to achieve voltage superposition of multiple sub-cells within the perovskite solar cell array. The output terminals of the crystalline silicon solar cell array and the perovskite solar cell array are connected in parallel, allowing both arrays to supply power. The front panel, first encapsulant film, crystalline silicon solar cell array, second encapsulant film, perovskite solar cell array, and waterproof backsheet are stacked sequentially to form a complete laminated structure. Lamination encapsulation cross-links and cures the first and second encapsulating films under heat, bonding the layers together to form a complete portable bifacial photovoltaic module. This application determines the number of perovskite sub-cells in series based on the output voltage of the crystalline silicon solar cell array, ensuring voltage matching between the two arrays and avoiding circulating current losses caused by voltage mismatch during direct parallel connection. By laser etching to divide the perovskite solar cell array and then connecting them in series after division, the number of perovskite sub-cells in series can be flexibly adjusted to adapt to different voltage matching requirements. Stacking the layers in a specific order and laminating them together to form an integrated laminated structure improves the module's structural stability and sealing performance.

[0032] Optionally, in some embodiments, the step of dividing the perovskite solar cell array into multiple perovskite sub-cells by laser etching and connecting the multiple perovskite sub-cells in series includes: sequentially preparing a first conductive layer and a perovskite light-absorbing layer on the side of the waterproof backsheet facing the front power generation unit; forming adjacent first and second etching grooves using laser etching, wherein the first etching groove penetrates the perovskite light-absorbing layer and exposes the first conductive layer, and the second etching groove penetrates the first conductive layer and the perovskite light-absorbing layer; filling the second etching groove with a second insulating layer, and partially filling the first etching groove with a first insulating layer, with a gap between the first and second insulating layers; depositing conductive material on the side of the perovskite light-absorbing layer away from the waterproof backsheet, wherein a portion of the conductive material enters the gap between the first and second insulating layers to form a conductive connection layer, and the remaining conductive material forms a second conductive layer on the surface of the perovskite light-absorbing layer; and forming a third etching groove on the side away from the first etching groove using laser etching, wherein the third etching groove penetrates the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells.

[0033] Thus, through the cooperation of the first etching tank, the second etching tank, the first insulating layer, the second insulating layer, the conductive connection layer, and the third etching tank, multiple perovskite sub-cells form a perovskite solar cell array connected in series. The number of perovskite sub-cells connected in series can be flexibly adjusted as needed to meet the voltage matching requirements with crystalline silicon solar cell arrays, which is beneficial for fabricating portable bifacial photovoltaic modules that generate electricity from both sides and have matching voltage.

[0034] Optionally, before sequentially preparing the first conductive layer and the perovskite light-absorbing layer on the side of the waterproof backsheet facing the front power generation unit, the method further includes: temporarily attaching the waterproof backsheet to a rigid carrier plate; preparing a perovskite light-absorbing material on the side of the waterproof backsheet away from the rigid carrier plate using a wet coating process, wherein the wet coating process is selected from at least one of slot coating, blade coating, or roller coating; and forming a perovskite light-absorbing layer by controlling the crystallization process, wherein the method of controlling the crystallization process includes at least one of nitrogen blowing, vacuum-assisted, or solvent annealing.

[0035] In some embodiments, optionally, the step of laminating and encapsulating the stacked structure to obtain a portable bifacial photovoltaic module includes: placing the stacked structure in a laminator; laminating using a segmented pressurization method, the segmented pressurization method including a first pressurization stage, a second pressurization stage, and a third pressurization stage performed sequentially; wherein, the pressure of the first pressurization stage is greater than or equal to 18 kPa and less than or equal to 22 kPa, and the duration is greater than or equal to 50 s and less than or equal to 70 s; the pressure of the second pressurization stage is greater than or equal to 45 kPa and less than or equal to 55 kPa, and the duration is greater than or equal to 50 s and less than or equal to 70 s; the pressure of the third pressurization stage is greater than or equal to 27 kPa and less than or equal to 33 kPa, and the duration is greater than or equal to 1000 s and less than or equal to 1400 s.

[0036] Thus, the first pressurization stage is a low-pressure venting stage, applying low pressure to the laminated structure to expel residual air between the layers, preventing air from forming bubbles within the laminated structure. The second pressurization stage is a high-pressure cross-linking stage, where higher pressure promotes full cross-linking and curing of the first and second adhesive films, while also ensuring tight adhesion between the layers. The third pressurization stage is a low-pressure holding stage, where lower pressure reduces residual stress within the laminated structure, preventing excessive stress from causing cracking in the crystalline silicon and perovskite sub-cells.

[0037] Optionally, the lamination temperature is controlled at 120℃±5℃, which is lower than the temperature threshold for thermal decomposition of perovskite materials, so as to avoid high temperature from damaging the structure and performance of the perovskite light absorption layer. Attached Figure Description

[0038] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0039] Figure 1 A schematic diagram of the structure of a portable bifacial photovoltaic module according to an embodiment of this application is shown;

[0040] Figure 2 A schematic diagram of the structure of a crystalline silicon solar cell pack according to an embodiment of this application is shown;

[0041] Figure 3 One of the structural schematic diagrams of a perovskite solar cell pack according to an embodiment of this application is shown;

[0042] Figure 4 It shows Figure 3 A magnified structural diagram at point A;

[0043] Figure 5 A second schematic diagram of the structure of a perovskite solar cell pack according to an embodiment of this application is shown;

[0044] Figure 6 It shows Figure 5 A magnified structural diagram at point B;

[0045] Figure 7 A schematic diagram of the front panel structure according to an embodiment of this application is shown;

[0046] Figure 8 A flowchart illustrating the fabrication process of a portable bifacial photovoltaic module according to an embodiment of this application is shown;

[0047] Figure 9 A flowchart illustrating the boost process of a perovskite battery pack according to an embodiment of this application is shown;

[0048] Figure 10 A flowchart illustrating the packaging process of a stacked structure according to an embodiment of this application is shown.

[0049] The 100 portable bifacial photovoltaic module comprises: 1 front panel, 11 PET substrate, 12 fluorine coating, 2 waterproof back panel, 3 front-side power generation unit, 31 crystalline silicon cell assembly, 311 crystalline silicon cell, 4 rear-side power generation unit, 41 perovskite cell assembly, 411 perovskite sub-cell, 51 first conductive layer, 52 perovskite light absorption layer, 521 isolation groove, 53 second conductive layer, 61 first etching groove, 611 insulation part, 612 conductive connection channel, 62 second etching groove, 63 third etching groove, 71 first insulating layer, 72 second insulating layer, 73 conductive connection layer, 81 first encapsulant film, and 82 second encapsulant film. Detailed Implementation

[0050] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0052] like Figure 1 , Figure 2 and Figure 3 As shown, the first aspect of this application provides a portable bifacial photovoltaic module 100, including: a front panel 1; a waterproof back panel 2, disposed opposite to the front panel 1; a front power generation unit 3, disposed between the front panel 1 and the waterproof back panel 2, the front power generation unit 3 including a crystalline silicon cell pack 31 formed by multiple crystalline silicon cells 311 connected in series; a rear power generation unit 4, disposed between the front power generation unit 3 and the waterproof back panel 2, the rear power generation unit 4 including a perovskite cell pack 41 formed by multiple perovskite sub-cells 411 connected in series; the crystalline silicon cell pack 31 and the perovskite cell pack 41 are connected in parallel, and the ratio of the number of crystalline silicon cells 311 in the crystalline silicon cell pack 31 to the number of perovskite sub-cells 411 in the perovskite cell pack 41 is configured according to the ratio of the open-circuit voltage of the crystalline silicon cell 311 to the open-circuit voltage of the perovskite sub-cell 411, so that the output voltage of the crystalline silicon cell pack 31 matches the output voltage of the perovskite cell pack 41.

[0053] The portable bifacial photovoltaic module 100 provided in this application includes a front panel 1, a waterproof backsheet 2, a front-side power generation unit 3, and a rear-side power generation unit 4. The front panel 1 and the waterproof backsheet 2 are arranged opposite to each other, and the front-side power generation unit 3 is disposed between the front panel 1 and the waterproof backsheet 2. The front-side power generation unit 3 includes a crystalline silicon cell array 31, which is formed by connecting multiple crystalline silicon cells 311 in series. The rear-side power generation unit 4 is disposed between the front-side power generation unit 3 and the waterproof backsheet 2, and includes a perovskite cell array 41, which is formed by connecting multiple perovskite sub-cells 411 in series. The crystalline silicon cell array 31 and the perovskite cell array 41 are connected in parallel. There is a ratio between the number of crystalline silicon solar cells 311 connected in series in the crystalline silicon solar cell array 31 and the number of perovskite sub-cells 411 connected in series in the perovskite solar cell array 41. This ratio is configured based on the ratio of the open-circuit voltage of the crystalline silicon solar cell 311 to the open-circuit voltage of the perovskite sub-cell 411, so that the output voltage of the crystalline silicon solar cell array 31 matches the output voltage of the perovskite solar cell array 41. The front panel 1 serves as a front protective layer, allowing sunlight to pass through the front panel 1 and illuminate the front power generation unit 3. The waterproof backsheet 2 is located on the back of the portable bifacial photovoltaic module 100, and the waterproof backsheet 2 can prevent external moisture from entering the module from the back of the module. The crystalline silicon solar cells 311 in the front power generation unit 3 absorb sunlight transmitted through the front panel 1 and convert it into electrical energy. The perovskite sub-cells 411 in the back power generation unit 4 can absorb light incident from the side of the waterproof backsheet 2, including ground reflected light and ambient scattered light, and convert light energy into electrical energy.

[0054] Since the crystalline silicon solar cell array 31 and the perovskite solar cell array 41 are respectively located on the front and back sides of the module, the two sets of cells independently receive light and perform photoelectric conversion. The output voltage of the crystalline silicon solar cell array 31 is determined by the number of crystalline silicon solar cells 311 connected in series and the open-circuit voltage of each crystalline silicon solar cell 311. The output voltage of the perovskite solar cell array 41 is determined by the number of perovskite sub-cells 411 connected in series and the open-circuit voltage of each perovskite sub-cell 411. By configuring the ratio of the number of cells in series according to the ratio of the open-circuit voltages of the two types of cells, it is possible to ensure that the two sets of cells output approximately equal voltages when operating independently. When the two sets of cells are connected in parallel, since the output voltages are already matched, there will be no circulating current loss between the two sets of cells due to voltage differences. The parallel connection allows the two sets of cells to operate at different current output levels without mutual restriction due to current differences. Therefore, the portable bifacial photovoltaic module 100 of this application has bifacial power generation capability, and can generate electricity simultaneously by utilizing direct sunlight on the front side and diffused and reflected light on the back side, thereby improving the light energy utilization rate per unit area. The crystalline silicon solar cell group 31 and the perovskite solar cell group 41 are located on the front and back sides of the portable bifacial photovoltaic module 100, respectively, and each performs photoelectric conversion independently. The two groups of cells are connected in parallel. By configuring the series ratio according to the open-circuit voltage ratio, the output voltages of the two groups of cells are matched, avoiding the circulating current loss caused by voltage mismatch when directly connected in parallel, and also avoiding the efficiency loss caused by current limitation when directly connected in series. Without increasing the overall area, this application increases the total power generation by setting the back-side power generation unit 4, thereby improving the overall output power of the portable bifacial photovoltaic module 100 and its power generation performance in practical application scenarios.

[0055] In some embodiments, optionally, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the perovskite solar cell 41 includes: a first conductive layer 51 disposed on the side of the waterproof backplate 2 facing the front power generation unit 3; a perovskite light absorption layer 52 disposed on the side of the first conductive layer 51 facing the front power generation unit 3; and a second conductive layer 53 disposed on the side of the perovskite light absorption layer 52 facing the front power generation unit 3. The perovskite light absorption layer 52 is divided into multiple perovskite sub-cells 411 arranged at intervals along a first direction by laser etching, and adjacent perovskite sub-cells 411 are connected in series with the first conductive layer 51 through the second conductive layer 53.

[0056] In this embodiment, the perovskite solar cell 41 includes a first conductive layer 51, a perovskite light-absorbing layer 52, and a second conductive layer 53. The first conductive layer 51 is disposed on the side of the waterproof backplate 2 facing the front power generation unit 3, the perovskite light-absorbing layer 52 is disposed on the side of the first conductive layer 51 facing the front power generation unit 3, and the second conductive layer 53 is disposed on the side of the perovskite light-absorbing layer 52 facing the front power generation unit 3. The perovskite light-absorbing layer 52 is divided into multiple perovskite sub-cells 411 by a laser etching process. The multiple perovskite sub-cells 411 are arranged at intervals along a first direction, and adjacent perovskite sub-cells 411 are connected in series with the first conductive layer 51 through the second conductive layer 53. The first conductive layer 51 serves as the bottom electrode of the perovskite sub-cell 411, collecting the charge carriers generated by the perovskite light-absorbing layer 52. The perovskite light-absorbing layer 52 is the core photoelectric conversion layer of the perovskite sub-cell, absorbing incident light and generating charge carriers. The second conductive layer 53 serves as the top electrode of the perovskite sub-cell 411, collecting the charge carriers generated by the perovskite light-absorbing layer 52. The perovskite light-absorbing layer 52 is laser-etched into multiple independent perovskite sub-cell 411 regions, each region constituting an independent perovskite sub-cell 411. Between adjacent perovskite sub-cells 411, the second conductive layer 53 of the previous perovskite sub-cell 411 and the first conductive layer 51 of the next perovskite sub-cell 411 are connected in series via a conductive material. The perovskite solar cell array 41 employs a multilayer thin-film structure, with the first conductive layer 51, the perovskite light-absorbing layer 52, and the second conductive layer 53 stacked sequentially to form a complete photoelectric conversion unit. The perovskite light-absorbing layer 52 can absorb light incident from both the front and back sides, achieving bi-lateral light-gathering power generation. By dividing the large-area perovskite light-absorbing layer 52 into multiple sub-cells and connecting them in series through laser etching, the voltage matching requirements of the perovskite solar cell 41 and the crystalline silicon solar cell 31 can be met while ensuring a high output voltage. The waterproof backsheet 2 directly supports the perovskite solar cell 41 and provides a moisture barrier for the perovskite material, thereby mitigating the performance degradation problem caused by moisture intrusion and improving the service life of the portable bifacial photovoltaic module 100.

[0057] Optionally, the first conductive layer 51 and the second conductive layer 53 are made of transparent conductive materials, so that light can pass through the first conductive layer 51 and the second conductive layer 53 to reach the perovskite light absorption layer 52, and at the same time, light incident from the waterproof backplate 2 can also enter the perovskite light absorption layer 52 and be absorbed and utilized.

[0058] In some embodiments, optionally, such as Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a plurality of isolation trenches 521 are provided on the perovskite light absorption layer 52 at intervals. The plurality of isolation trenches 521 divide the perovskite light absorption layer 52 into a plurality of perovskite sub-cells 411 arranged at intervals along a first direction. The isolation trenches 521 include a first etching trench 61 and a second etching trench 62 arranged adjacent to each other. The first etching trench 61 penetrates the perovskite light absorption layer 52 and exposes the first conductive layer 51. The second etching trench 62 penetrates the first conductive layer 51 and the perovskite light absorption layer 52.

[0059] In this embodiment, a plurality of isolation trenches 521 are spaced apart on the perovskite light-absorbing layer 52, dividing the perovskite light-absorbing layer 52 into a plurality of perovskite sub-cells 411 arranged at intervals along a first direction. The isolation trenches 521 include adjacent first etching trenches 61 and second etching trenches 62. The first etching trench 61 penetrates the perovskite light-absorbing layer 52 and exposes the first conductive layer 51, while the second etching trench 62 penetrates both the first conductive layer 51 and the perovskite light-absorbing layer 52. The first etching trench 61 defines the boundary between adjacent perovskite sub-cells 411, separating them from each other on the perovskite light-absorbing layer 52. The second etching trench 62 forms channel regions for series connection of sub-cells within the perovskite solar cell array 41. Multiple isolation trenches 521 divide the entire perovskite light-absorbing layer 52 into multiple perovskite sub-cells 411 arranged sequentially along a first direction. A first etching trench 61 and a second etching trench 62 are configured in conjunction. The first etching trench 61 achieves photoelectric isolation between sub-cells, while the second etching trench 62 provides a structural basis for series connection between sub-cells. Therefore, by setting the isolation trenches 521, this application divides the large-area perovskite light-absorbing layer 52 into multiple independent sub-cell units, each with independent photoelectric conversion capability. The first etching trench 61 penetrates the perovskite light-absorbing layer 52 and exposes the first conductive layer 51, effectively preventing leakage paths between adjacent sub-cells through the perovskite light-absorbing layer 52 and ensuring electrical independence between each sub-cell. The second etching trench 62 penetrates the first conductive layer 51 and the perovskite light-absorbing layer 52, breaking the continuity of the first conductive layer 51 between adjacent sub-cells, providing a series connection position for the subsequent deposition of the conductive connection layer 73, which is beneficial for achieving voltage superposition of multiple perovskite sub-cells 411. The isolation groove 521 helps the perovskite solar cell 41 to obtain a higher output voltage, and at the same time helps to match the output voltage of the perovskite solar cell 41 with the output voltage of the crystalline silicon solar cell 31.

[0060] In some embodiments, optionally, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the first etching tank 61 includes an insulating portion 611 and a conductive connection channel 612, with the conductive connection channel 612 located between the insulating portion 611 and the second etching tank 62. The insulating portion 611 of the first etching tank 61 is filled with a first insulating layer 71, and the second etching tank 62 is filled with a second insulating layer 72. The perovskite solar cell 41 also includes a conductive connection layer 73, with the conductive connection channel 612 filled with the conductive connection layer 73. The conductive connection layer 73 connects the second conductive layer 53 of one perovskite sub-cell 411 and the first conductive layer 51 of an adjacent perovskite sub-cell 411 in series. The perovskite solar cell 41 also includes a plurality of third etching tanks 63, which are located on the side of the first etching tank 61 away from the first conductive layer 51 and penetrate the second conductive layer 53 to disconnect the second conductive layer 53 and the conductive connection layer 73 between two adjacent perovskite sub-cells 411.

[0061] In this embodiment, the first etching trench 61 includes an insulating portion 611 and a conductive connection channel 612. The conductive connection channel 612 is located between the insulating portion 611 and the second etching trench 62. The insulating portion 611 of the first etching trench 61 is filled with a first insulating layer 71, and the second etching trench 62 is filled with a second insulating layer 72. The perovskite solar cell 41 also includes a conductive connection layer 73, which is filled within the conductive connection channel 612. The conductive connection layer 73 connects the second conductive layer 53 of one perovskite sub-cell 411 in series with the first conductive layer 51 of an adjacent perovskite sub-cell 411. The perovskite solar cell 41 also includes a plurality of third etching trenches 63, which penetrate the second conductive layer 53. The third etching trenches 63 disconnect the second conductive layer 53 and the conductive connection layer 73 between two adjacent perovskite sub-cells 411. The first insulating layer 71 filled in the insulating portion 611 of the first etching tank 61 provides electrical isolation between adjacent perovskite sub-cells 411 and the perovskite light-absorbing layer 52 and the conductive connection layer 73. The second insulating layer 72 filled in the second etching tank 62 provides electrical isolation between the first conductive layer 51 and the perovskite light-absorbing layer 52 of adjacent perovskite sub-cells 411 at the location of the second etching tank 62. The conductive connection channel 612 is located between the first insulating layer 71 and the second insulating layer 72, and the conductive connection layer 73 filled in the conductive connection channel 612 provides an electrical connection path between adjacent perovskite sub-cells 411. The conductive connection layer 73 starts from the second conductive layer 53 of the first perovskite sub-cell 411, passes through the conductive connection channel 612, and connects to the first conductive layer 51 of the adjacent perovskite sub-cell 411, thereby realizing a series connection between the top electrode of the first perovskite sub-cell 411 and the bottom electrode of the adjacent perovskite sub-cell 411. The third etching trench 63 penetrates the second conductive layer 53 and the conductive connection layer 73. The third etching trench 63 cuts off the second conductive layer 53 between two adjacent perovskite sub-cells 411, and simultaneously cuts off the continuous portion of the conductive connection layer 73 on the surface of the second conductive layer 53. The third etching trench 63 prevents unnecessary electrical connections between adjacent sub-cells from forming, avoiding short circuits between the positive and negative electrodes. Through the cooperation of the first etching trench 61, the second etching trench 62, and the third etching trench 63, multiple perovskite sub-cells 411 form a perovskite solar cell group 41 connected in series. By adjusting the number of perovskite sub-cells 411 connected in series, this application can match the output voltage of the perovskite solar cell group 41 with the output voltage of the crystalline silicon solar cell group 31. Simultaneously, the insulating and conductive materials filled in the first etching trench 61 and the second etching trench 62 help reduce resistance loss in the series connection area and improve the overall photoelectric conversion efficiency.

[0062] Optionally, one of the bottom electrode and the top electrode is a positive electrode, and the other is a negative electrode.

[0063] In some embodiments, optionally, the number N of the perovskite sub-cells 411 connected in series and the number M of the crystalline silicon cells 311 connected in series satisfy the following:

[0064] ;

[0065] in, This represents the open-circuit voltage of a single crystalline silicon solar cell 311. The open-circuit voltage of a single perovskite sub-cell 411 is represented by α, which represents the compensation coefficient, and α is greater than or equal to 0.9 and less than or equal to 1.1.

[0066] Thus, this application constructs a precise matching relationship between the series ratio of crystalline silicon solar cell 31 and perovskite solar cell 41 and the open-circuit voltage ratio through the above formula, and introduces a compensation coefficient α to reserve adjustment margin for engineering deviations, so that the two sets of cells can still maintain basic matching of output voltage under the conditions of operating temperature changes and batch production errors, fundamentally eliminating circulating current losses caused by voltage mismatch.

[0067] Optionally, the open-circuit voltage of a single crystalline silicon solar cell 311 is 0.71V, the open-circuit voltage of a single perovskite sub-cell 411 is 1.1V; and / or the ratio of the number of perovskite sub-cells 411 connected in series to the number of crystalline silicon solar cells 311 connected in series is 6:10.

[0068] In this embodiment, the open-circuit voltage of a single crystalline silicon solar cell 311 is 0.71V, and the open-circuit voltage of a single perovskite sub-cell 411 is 1.1V. The number of cells connected in series can be calculated based on the open-circuit voltage of each cell. By configuring the number of perovskite sub-cells 411 connected in series to the number of crystalline silicon solar cells 311 in a 6:10 ratio, the total output voltage of the perovskite solar cell assembly 41 is approximately equal to the total output voltage of the crystalline silicon solar cell assembly 311. According to the principle of series voltage superposition, the total output voltage of the crystalline silicon solar cell assembly 31 is equal to the product of the number of crystalline silicon solar cells 311 connected in series and the open-circuit voltage of a single crystalline silicon solar cell 311. Similarly, the total output voltage of the perovskite solar cell assembly 41 is equal to the product of the number of perovskite sub-cells 411 connected in series and the open-circuit voltage of a single perovskite sub-cell 411. By configuring the number of perovskite sub-cells 411 in series with the number of crystalline silicon cells 311 in series to be 6:10, the total output voltage of the perovskite cell pack 41 is basically the same as the total output voltage of the crystalline silicon cell pack 31. This avoids circulating current loss between the two sets of cells due to voltage differences, and also avoids efficiency loss due to current limitation when the two sets of cells are directly connected in series.

[0069] Optionally, the water vapor transmission rate of the waterproof backing 2 is less than or equal to 6 × 10⁻⁶. -5 g / (m2 ·day).

[0070] In this embodiment, a waterproof backsheet 2 is disposed on the back side of the perovskite solar cell 41, isolating the perovskite light-absorbing layer 52 from the external environment. The water vapor transmittance of the waterproof backsheet 2 is less than or equal to 6 × 10⁻⁶. -5 g / (m 2 ·day), where g / (m 2 The value (day) indicates the mass of water vapor allowed to pass through each square meter of the waterproof backsheet 2 in grams per day. A lower value indicates a stronger ability of the waterproof backsheet 2 to block water vapor. The perovskite material in the perovskite light-absorbing layer 52 is sensitive to water vapor and is prone to decomposition in a humid environment, leading to a decrease in photoelectric conversion performance. The waterproof backsheet 2 effectively slows down the degradation process of the perovskite material in a humid environment, extending the lifespan of the perovskite solar cell 41 in humid environments. The waterproof backsheet 2 also has light transmittance, allowing light to pass through it to reach the perovskite light-absorbing layer 52. This enables the perovskite solar cell 41 to generate electricity using light incident from the back of the portable bifacial photovoltaic module 100, while also improving the overall output power and lifespan of the portable bifacial photovoltaic module 100.

[0071] In some embodiments, optionally, such as Figures 1 to 6 As shown, the portable bifacial photovoltaic module 100 further includes: a first encapsulant film 81 disposed between the front panel 1 and the front power generation unit 3; and a second encapsulant film 82 disposed between the front power generation unit 3 and the back power generation unit 4.

[0072] In this embodiment, the first adhesive film 81 firmly bonds the front panel 1 to the front power generation unit 3, and the second adhesive film 82 firmly bonds the front power generation unit 3 to the back power generation unit 4, forming a complete laminate. The first and second adhesive films 81 and 82 can buffer external stresses experienced during lamination and use of the portable bifacial photovoltaic module 100, reducing the impact of stress on the crystalline silicon solar cells 311 and perovskite sub-solar cells 411, and lowering the risk of cell cracking. The first and second adhesive films 81 and 82 have high light transmittance, facilitating light transmission to the front power generation unit 3 and the back power generation unit 4, reducing optical loss. After cross-linking and curing, the first and second adhesive films 81 and 82 form a dense encapsulation layer, which helps improve the overall structural stability and sealing performance of the portable bifacial photovoltaic module 100.

[0073] Optionally, both the first encapsulant film 81 and the second encapsulant film 82 are ultra-low temperature cross-linked POE films, which can reduce the lamination and encapsulation temperature to 120℃±5℃, avoiding thermal damage to the perovskite light-absorbing layer 52 caused by traditional lamination and encapsulation temperatures. Perovskite materials are prone to thermal decomposition at temperatures exceeding 130℃. The ultra-low temperature cross-linked POE film keeps the lamination temperature below the thermal decomposition threshold of perovskite materials, which helps maintain the structural integrity and photoelectric conversion performance of the perovskite light-absorbing layer 52. After cross-linking and curing, the ultra-low temperature cross-linked POE film forms a dense three-dimensional network structure with low permeability to water vapor and oxygen, reducing the entry of external water vapor and oxygen into the perovskite light-absorbing layer 52 and the crystalline silicon solar cell 311 through the encapsulation film.

[0074] In some embodiments, optionally, such as Figure 7 As shown, the front panel 1 includes a PET (Polyethylene Terephthalate) substrate and a fluorine-containing coating 12. The fluorine-containing coating 12 is disposed on the surface of the PET substrate 11 facing away from the waterproof back panel 2. The thickness of the front panel 1 is greater than or equal to 0.3 mm and less than or equal to 0.6 mm.

[0075] In this embodiment, the front panel 1 includes a PET substrate 11 and a fluorinated coating 12. The PET substrate 11 serves as the basic support layer of the front panel 1, possessing mechanical strength and light transmittance, and provides structural support for the portable bifacial photovoltaic module 100. The fluorinated coating 12 is disposed on the surface of the PET substrate 11 facing away from the waterproof back panel 2, and is located as the outermost layer of the portable bifacial photovoltaic module 100. The fluorinated coating 12 is hydrophobic, reducing the amount of dust and contaminants adhering to the surface of the front panel 1. The fluorinated coating 12 resists ultraviolet radiation damage to the PET substrate 11, delaying the aging of the PET substrate 11 during outdoor use. The fluorinated coating 12 improves the scratch resistance of the front panel 1 surface, reducing the possibility of surface scratches on the portable bifacial photovoltaic module 100 during use and carrying.

[0076] The thickness of the front panel 1 is greater than or equal to 0.3 mm and less than or equal to 0.6 mm, giving it sufficient mechanical strength to support the front power generation unit 3 and the back power generation unit 4, while maintaining the flexibility and lightweight of the portable bifacial photovoltaic module 100. The front panel 1 allows sunlight to pass through and reach the front power generation unit 3, enabling the front power generation unit 3 to receive incident light and perform photoelectric conversion. In the portable bifacial photovoltaic module 100, the front panel 1 adopts a composite structure of a PET substrate 11 and a fluorinated coating 12. The fluorinated coating 12 is located on the outermost layer, which can reduce performance loss caused by surface contamination and ultraviolet aging.

[0077] Based on the same technical concept, a second aspect of this application provides a method for preparing a portable bifacial photovoltaic module, used to prepare the portable bifacial photovoltaic module as proposed in the first aspect, such as... Figure 8 As shown, the method for fabricating a portable bifacial photovoltaic module includes:

[0078] S101: Obtain front panel, waterproof backsheet, crystalline silicon solar cells and perovskite solar cell pack;

[0079] S103: Crystalline silicon solar cells are connected in series by welding ribbons to form a crystalline silicon solar cell pack;

[0080] S105: Determine the number of perovskite sub-cells to be connected in series based on the output voltage of the crystalline silicon solar cell pack.

[0081] S107: Divide the perovskite solar cell into multiple perovskite sub-cells by laser etching and connect the multiple perovskite sub-cells in series.

[0082] S109: Connect the output terminal of the crystalline silicon solar cell pack in parallel with the output terminal of the perovskite solar cell pack;

[0083] S111: The front panel, first encapsulant film, crystalline silicon solar cell, second encapsulant film, perovskite solar cell and waterproof backplate are stacked in sequence to form a laminated structure.

[0084] S113: A portable bifacial photovoltaic module is obtained by laminating and encapsulating a stacked structure.

[0085] According to the method for fabricating a portable bifacial photovoltaic module proposed in this application, a front panel, a waterproof backsheet, crystalline silicon solar cells, and a perovskite solar cell array are obtained as starting materials. Crystalline silicon solar cells are connected in series with solder ribbons to form a crystalline silicon solar cell array. This series welding superimposes the voltages of multiple crystalline silicon solar cells, and the output voltage of the crystalline silicon solar cell array is determined by the number of crystalline silicon solar cells connected in series and the open-circuit voltage of each individual crystalline silicon solar cell. The number of perovskite sub-cells connected in series is determined based on the output voltage of the crystalline silicon solar cell array, ensuring that the output voltage of the perovskite solar cell array matches that of the crystalline silicon solar cell array. Laser etching divides the entire perovskite solar cell array into multiple perovskite sub-cells. These divided perovskite sub-cells are then connected in series with conductive materials to achieve voltage superposition of multiple sub-cells within the perovskite solar cell array. The output terminals of the crystalline silicon solar cell array and the perovskite solar cell array are connected in parallel, allowing both arrays to supply power. The front panel, first encapsulant film, crystalline silicon solar cell array, second encapsulant film, perovskite solar cell array, and waterproof backsheet are stacked sequentially to form a complete laminated structure. Lamination encapsulation cross-links and cures the first and second encapsulating films under heat, bonding the layers together to form a complete portable bifacial photovoltaic module. This application determines the number of perovskite sub-cells in series based on the output voltage of the crystalline silicon solar cell array, ensuring voltage matching between the two arrays and avoiding circulating current losses caused by voltage mismatch during direct parallel connection. By laser etching to divide the perovskite solar cell array and then connecting them in series after division, the number of perovskite sub-cells in series can be flexibly adjusted to adapt to different voltage matching requirements. Stacking the layers in a specific order and laminating them together to form an integrated laminated structure improves the module's structural stability and sealing performance.

[0086] In some embodiments, optionally, such as Figure 9 As shown, the steps of dividing a perovskite solar cell into multiple perovskite sub-cells by laser etching and connecting the multiple perovskite sub-cells in series include:

[0087] S1071: The first conductive layer and the perovskite light-absorbing layer are sequentially prepared on the side of the waterproof backplate facing the front power generation unit.

[0088] S1073: A first etching trench and a second etching trench are formed by laser etching, which are arranged adjacently. The first etching trench penetrates the perovskite light-absorbing layer and exposes the first conductive layer. The second etching trench penetrates the first conductive layer and the perovskite light-absorbing layer.

[0089] S1075: A second insulating layer is filled in the second etching tank, and a first insulating layer is filled in a portion of the first etching tank, with a gap between the first insulating layer and the second insulating layer.

[0090] S1077: A conductive material is deposited on the side of the perovskite light-absorbing layer away from the waterproof backing. Part of the conductive material enters the gap between the first and second insulating layers to form a conductive connection layer. The remaining conductive material forms a second conductive layer on the surface of the perovskite light-absorbing layer.

[0091] S1079: A third etching trench is formed on the side away from the first etching trench by laser etching. The third etching trench penetrates the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells.

[0092] In this embodiment, during the process of dividing the perovskite solar cell into multiple perovskite sub-cells by laser etching and connecting these sub-cells in series, a first conductive layer and a perovskite light-absorbing layer are sequentially prepared on the side of the waterproof backsheet facing the crystalline silicon solar cell. Adjacent first and second etching trenches are formed using laser etching. The first etching trench penetrates the perovskite light-absorbing layer and exposes the first conductive layer, while the second etching trench penetrates both the first conductive layer and the perovskite light-absorbing layer. A second insulating layer is filled within the second etching trench, and a portion of the first etching trench is filled with the first insulating layer, leaving a gap between the first and second insulating layers. Conductive material is deposited on the side of the perovskite light-absorbing layer facing away from the waterproof backsheet. Part of the conductive material enters the gap between the first and second insulating layers to form a conductive connection layer, while the remaining conductive material forms a second conductive layer on the surface of the perovskite light-absorbing layer. A third etching trench is formed on the side facing away from the first etching trench using laser etching. The third etching trench penetrates the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells. The first etching trench breaks the perovskite light-absorbing layer between adjacent sub-cells, the second etching trench breaks the first conductive layer between adjacent sub-cells, and the first and second insulating layers electrically isolate adjacent sub-cells. A conductive connection layer formed in the gap between the first and second insulating layers connects the second conductive layer of the preceding perovskite sub-cell in series with the first conductive layer of the following perovskite sub-cell. The third etching trench cuts off the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells, preventing a short circuit after the series connection is completed. Through the cooperation of the first etching trench, the second etching trench, the first insulating layer, the second insulating layer, the conductive connection layer, and the third etching trench, multiple perovskite sub-cells form a perovskite solar cell array connected in series.

[0093] Laser etching technology enables precise formation of etching grooves on a large-area perovskite light-absorbing layer on a waterproof backsheet, dividing the perovskite light-absorbing layer into multiple sub-cell regions. The filling of the first and second insulating layers provides reliable electrical isolation between adjacent sub-cells. During deposition, conductive materials simultaneously form a conductive connection layer and a second conductive layer. The conductive connection layer enables series connection between adjacent sub-cells, while the second conductive layer serves as the top electrode for each sub-cell. The simultaneous formation of these two functional layers in a single deposition process simplifies the process. A third etching groove breaks the continuity between the second conductive layer and the conductive connection layer between adjacent sub-cells, preventing additional short-circuit paths after series connection. This application enables the fabrication of perovskite solar cell arrays with multiple series-connected sub-cells on a flexible waterproof backsheet. The number of perovskite sub-cells in series can be flexibly adjusted to meet voltage matching requirements with crystalline silicon solar cell arrays, facilitating the fabrication of portable bifacial photovoltaic modules with bifacial power generation and voltage matching.

[0094] Optionally, before sequentially preparing the first conductive layer and the perovskite light-absorbing layer on the side of the waterproof backsheet facing the crystalline silicon solar cell, the method further includes: temporarily attaching the waterproof backsheet to a rigid carrier plate; preparing a perovskite light-absorbing material on the side of the waterproof backsheet away from the rigid carrier plate using a wet coating process, wherein the wet coating process is selected from at least one of slot coating, blade coating, or roller coating; and forming a perovskite light-absorbing layer by controlling the crystallization process, wherein the method of controlling the crystallization process includes at least one of nitrogen blowing, vacuum-assisted, or solvent annealing.

[0095] In some embodiments, optionally, such as Figure 10 As shown, the steps for laminating and encapsulating a stacked structure to obtain a portable bifacial photovoltaic module include:

[0096] S1131: Place the laminated structure in a laminator;

[0097] S1133: Lamination is performed using a segmented pressurization method, which includes a first pressurization stage, a second pressurization stage, and a third pressurization stage performed sequentially.

[0098] In this embodiment, the laminated structure is placed in a laminator and laminated using a segmented pressurization method. The laminator provides the lamination temperature and pressure conditions. After the laminated structure is placed inside the laminator, the laminator applies pressure and heat to the laminated structure. The first pressurization stage is a low-pressure venting stage, applying a low pressure to the laminated structure to expel residual air between the layers, preventing air from remaining in the laminated structure and forming bubbles. The second pressurization stage is a high-pressure cross-linking stage, where the higher pressure promotes full cross-linking and curing of the first and second adhesive films, while also ensuring a tight bond between the layers. The third pressurization stage is a low-pressure holding stage, where the lower pressure reduces residual stress inside the laminated structure, preventing excessive stress from causing cracks in the crystalline silicon solar cells and perovskite sub-cells.

[0099] Optionally, the lamination temperature is controlled at 120℃±5℃, which is lower than the temperature threshold for thermal decomposition of perovskite materials, so as to avoid high temperature from damaging the structure and performance of the perovskite light absorption layer.

[0100] In one specific embodiment, such as Figures 1 to 7 As shown, this application proposes a portable bifacial photovoltaic module. The portable bifacial photovoltaic module has a stacked structure of six layers, which are encapsulated by integral lamination. The front panel is a PET sheet with a fluorine-coated surface, with a thickness of 0.3 mm to 0.6 mm, serving as structural support and front protection. A first encapsulating film is provided between the front panel and the front power generation unit, and a second encapsulating film is provided between the front power generation unit and the back power generation unit. Both the first and second encapsulating films use ultra-low temperature cross-linked POE, with the activation energy of the cross-linking reaction reduced through chemical modification or the addition of special initiators. The front power generation unit is a crystalline silicon cell array, formed by multiple crystalline silicon cells connected in series. The substrate of the crystalline silicon cell is a silicon wafer, and the cell technology can be selected from PERC (Passivated Emitter and Rear Cell), TOPCon (Tunnel Oxide Passivated Contact), HJT (Heterojunction Technology), or XBC (X Back Contact Cell), etc. The rear-side power generation unit is a perovskite battery pack, positioned between the front-side power generation unit and the waterproof backplate. The waterproof backplate includes a high-performance water-resistant membrane.

[0101] In the fabrication of portable bifacial photovoltaic modules, a waterproof backsheet is used as a substrate on which perovskite solar cells are fabricated. The fabrication of perovskite solar cells mainly adopts a wet coating process: a flexible water-blocking film is first temporarily attached to a rigid substrate such as glass, and functional thin films are sequentially fabricated on the substrate using methods such as slot coating, blade coating, or roll coating. A high-quality perovskite light-absorbing layer is formed by controlling the crystallization process (such as nitrogen blowing, vacuum-assisted, and solvent annealing). Then, electron transport layers, hole transport layers, and other functional layers and electrode layers are deposited sequentially.

[0102] The perovskite solar cell uses laser etching to connect sub-cells in series, thereby achieving a series voltage boost. Specifically, a first conductive layer is first deposited on the side of the waterproof backplate facing the front power generation unit, and then a perovskite light-absorbing layer is fabricated on the first conductive layer. Laser etching P1 is used to cut through the perovskite light-absorbing layer, and laser etching P2 is used to cut through both the first conductive layer and the perovskite light-absorbing layer. P2 divides the entire cell unit into several perovskite sub-cells spaced apart along a first direction. Then, an insulating layer is filled near the cell ends of P1 and P2 in the laser etching paths using a mask to prevent internal short circuits at the cell edges after the second conductive layer is deposited, while also spacing adjacent perovskite sub-cells apart. A hollow area is formed between the two insulating layers for depositing a conductive connection layer. Subsequently, a conductive material is deposited on the surface. The conductive material in the hollow area (i.e., the conductive connection layer) connects the second conductive layer of the previous perovskite sub-cell in series with the first conductive layer of the next perovskite sub-cell. Finally, laser etching of P3 is used to cut off the first conductive layer to avoid short circuits between the positive and negative electrodes of the sub-cells, thus completing the series connection between multiple perovskite sub-cells.

[0103] The open-circuit voltage of a single perovskite sub-cell is approximately 1.1V, while that of a crystalline silicon cell is approximately 0.71V. To ensure voltage matching between the perovskite and crystalline silicon cell arrays when connected in parallel, the ratio of the number of perovskite sub-cells in series to the number of crystalline silicon cells in series is approximately 0.71:1.1, or approximately 6:10. Crystalline silicon cell arrays are constructed by cutting crystalline silicon cells and then soldering the positive and negative electrodes together using solder ribbons, achieving series voltage boosting of the cells.

[0104] Both the first and second films are made of ultra-low temperature cross-linked POE film. By adding cross-linking agents (such as ethylhexyl tert-butyl carbonate) and modifiers (such as silane coupling agents), peroxides are used to initiate the generation of free radicals in the POE molecular chains at a lower temperature, which then leads to a cross-linking reaction, thereby achieving low-temperature encapsulation.

[0105] The front panel, first encapsulant film, crystalline silicon solar cell assembly, second encapsulant film, perovskite solar cell assembly, and waterproof backsheet are sequentially stacked to form a laminated structure. The lamination temperature is controlled at 120℃±5℃ (traditional lamination temperature is 140℃~150℃), and a segmented pressurization method is used for lamination. The segmented pressurization adopts a low-high-low pressure curve: the first pressurization stage is 20kPa for 60s, used for low-pressure venting; the second pressurization stage is 50kPa for 60s, used for high-pressure to promote cross-linking and adhesion of the encapsulant film; the third pressurization stage is 30kPa for 1200s, used for low-pressure stress release to prevent excessive stress from causing cell cracking. Under the above conditions, the degree of cross-linking of the first and second encapsulant films is 75%~85%.

[0106] Table 1

[0107]

[0108] As shown in Table 1, Table 1 presents a comparison table of the power generation efficiency of the crystalline silicon perovskite tandem solar cell proposed in this application and ordinary crystalline silicon solar cells. The standard test condition is an irradiance of 1000 W / m². 2 AM1.5 spectrum, temperature 25℃, and nominal power irradiance of 1000W / m² on both sides. 2 And the back 135W / m 2 This is used to measure the power generation performance of bifacial modules, with a nominal operating cell temperature condition of 800 W / m² irradiance. 2 An ambient temperature of 20℃ and a wind speed of 1m / s were used to simulate the actual outdoor working conditions of the modules. Baseline 1 is a monofacial crystalline silicon module, and Baseline 2 is a crystalline silicon perovskite tandem module.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one embodiment or example.

[0110] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A portable bifacial photovoltaic module, characterized in that, include: front panel; A waterproof back panel is disposed opposite to the front panel; A front-side power generation unit is disposed between the front panel and the waterproof back panel. The front-side power generation unit includes a crystalline silicon battery pack formed by connecting multiple crystalline silicon solar cells in series. A rear power generation unit is disposed between the front power generation unit and the waterproof backplate. The rear power generation unit includes a perovskite battery pack formed by connecting multiple perovskite sub-cells in series. The crystalline silicon solar cell pack and the perovskite solar cell pack are connected in parallel. The ratio of the number of crystalline silicon solar cells in the crystalline silicon solar cell pack to the number of perovskite sub-cells in the perovskite solar cell pack is configured according to the ratio of the open-circuit voltage of the crystalline silicon solar cells to the open-circuit voltage of the perovskite sub-cells, so that the output voltage of the crystalline silicon solar cell pack matches the output voltage of the perovskite solar cell pack.

2. The portable bifacial photovoltaic module according to claim 1, characterized in that, The perovskite solar cell pack includes: A first conductive layer is disposed on the side of the waterproof backplate facing the front power generation unit; A perovskite light-absorbing layer is disposed on the side of the first conductive layer facing the front power generation unit; The second conductive layer is disposed on the side of the perovskite light-absorbing layer facing the front power generation unit; The perovskite light-absorbing layer is divided into multiple perovskite sub-cells arranged at intervals along a first direction by laser etching, and adjacent perovskite sub-cells are connected in series with the first conductive layer through the second conductive layer.

3. The portable bifacial photovoltaic module according to claim 2, characterized in that, The perovskite light absorption layer is provided with a plurality of isolation grooves at intervals, and the plurality of isolation grooves divide the perovskite light absorption layer into a plurality of perovskite sub-cells arranged at intervals along the first direction. The isolation trench includes a first etching trench and a second etching trench arranged adjacent to each other. The first etching trench penetrates the perovskite light-absorbing layer and exposes the first conductive layer. The second etching trench penetrates the first conductive layer and the perovskite light-absorbing layer.

4. The portable bifacial photovoltaic module according to claim 3, characterized in that, The first etching tank includes an insulating portion and a conductive connection channel, wherein the conductive connection channel is located between the insulating portion and the second etching tank; The insulating portion of the first etching tank is filled with a first insulating layer, and the second etching tank is filled with a second insulating layer. The perovskite solar cell also includes a conductive connection layer, the conductive connection channel being filled with the conductive connection layer, the conductive connection layer connecting the second conductive layer of one perovskite sub-cell and the first conductive layer of an adjacent perovskite sub-cell in series. The perovskite solar cell also includes a plurality of third etching grooves, which are located on the side of the first etching groove away from the first conductive layer and penetrate the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells.

5. The portable bifacial photovoltaic module according to claim 1, characterized in that, The number N of perovskite sub-cells connected in series and the number M of crystalline silicon cells connected in series satisfy the following: ； in, This represents the open-circuit voltage of a single crystalline silicon solar cell. The open-circuit voltage of a single perovskite subcell is represented by α, which represents the compensation coefficient, and α is greater than or equal to 0.9 and less than or equal to 1.

1.

6. The portable bifacial photovoltaic module according to any one of claims 1 to 5, characterized in that, The portable bifacial photovoltaic module also includes: A first adhesive film is disposed between the front panel and the front power generation unit; The second adhesive film is disposed between the front power generation unit and the back power generation unit.

7. The portable bifacial photovoltaic module according to any one of claims 1 to 5, characterized in that, The front panel includes a PET substrate and a fluorine-containing coating, wherein the fluorine-containing coating is disposed on the surface of the PET substrate opposite to the waterproof back panel; The thickness of the front plate is greater than or equal to 0.3 mm and less than or equal to 0.6 mm.

8. A method for preparing a portable bifacial photovoltaic module, characterized in that, A method for preparing a portable bifacial photovoltaic module as described in any one of claims 1 to 7, wherein the method for preparing the portable bifacial photovoltaic module comprises: Acquire front panel, waterproof backsheet, crystalline silicon solar cells and perovskite solar cell packs; The crystalline silicon solar cells are connected in series by welding ribbons to form a crystalline silicon solar cell pack; The number of perovskite sub-cells to be connected in series is determined based on the output voltage of the crystalline silicon solar cell pack. The perovskite solar cell array is divided into multiple perovskite sub-cells by laser etching, and the multiple perovskite sub-cells are connected in series. The output terminal of the crystalline silicon solar cell group is connected in parallel with the output terminal of the perovskite solar cell group. The front panel, the first adhesive film, the crystalline silicon solar cell, the second adhesive film, the perovskite solar cell, and the waterproof back panel are stacked in sequence to form a layered structure. The portable bifacial photovoltaic module is obtained by laminating and encapsulating the stacked structure.

9. The method for preparing a portable bifacial photovoltaic module according to claim 8, characterized in that, The step of dividing the perovskite solar cell array into multiple perovskite sub-cells by laser etching and connecting the multiple perovskite sub-cells in series includes: A first conductive layer and a perovskite light-absorbing layer are sequentially prepared on the side of the waterproof backplate facing the front power generation unit. Laser etching is used to form a first etching trench and a second etching trench arranged adjacent to each other. The first etching trench penetrates the perovskite light-absorbing layer and exposes the first conductive layer. The second etching trench penetrates the first conductive layer and the perovskite light-absorbing layer. A second insulating layer is filled in the second etching tank, and a first insulating layer is filled in a portion of the first etching tank, with a gap between the first insulating layer and the second insulating layer; Conductive material is deposited on the side of the perovskite light-absorbing layer away from the waterproof backing. Part of the conductive material enters the gap between the first insulating layer and the second insulating layer to form a conductive connection layer. The remaining conductive material forms a second conductive layer on the surface of the perovskite light-absorbing layer. A third etching trench is formed on the side opposite to the first etching trench by laser etching. The third etching trench penetrates the second conductive layer to disconnect the second conductive layer and the conductive connection layer between two adjacent perovskite sub-cells.

10. The method for preparing a portable bifacial photovoltaic module according to claim 8, characterized in that, The step of laminating and encapsulating the stacked structure to obtain the portable bifacial photovoltaic module includes: The laminated structure is placed in a laminator; Lamination is performed using a segmented pressurization method, which includes a first pressurization stage, a second pressurization stage, and a third pressurization stage performed sequentially. The pressure in the first pressurization stage is greater than or equal to 18 kPa and less than or equal to 22 kPa, and the duration is greater than or equal to 50 s and less than or equal to 70 s; the pressure in the second pressurization stage is greater than or equal to 45 kPa and less than or equal to 55 kPa, and the duration is greater than or equal to 50 s and less than or equal to 70 s; the pressure in the third pressurization stage is greater than or equal to 27 kPa and less than or equal to 33 kPa, and the duration is greater than or equal to 1000 s and less than or equal to 1400 s.

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