Solar cell packaging method, solar cell and solar wing

Abstract

The application discloses a solar cell packaging method, a solar cell and a solar wing, and belongs to the technical field of solar cell packaging, and aims to solve the technical problems of low use reliability and short service life of the existing solar wing in a severe space environment. The solar cell comprises a cell piece array, a welding strip, a bus bar and a packaging layer. The packaging steps of the solar cell are as follows: the cell pieces are arranged in an array, and a plurality of cell pieces in the cell piece array are connected in series into a cell piece string through the welding strip, and a plurality of welding strips are electrically connected with the bus bar through welding points; the cell pieces are arranged in a cavity of a forming mold, and the cell pieces are fixed; packaging paste is poured into the cavity of the forming mold, and the packaging paste covers the cell piece array, the welding strip and part of the bus bar; and the packaging paste is solidified, and the packaging layer is formed outside the cell piece array, the welding strip and part of the bus bar. The packaging method can improve the use reliability of the cell in the severe space environment, and the service life of the cell is longer.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology, and relates to solar cell packaging technology, and more particularly to a solar cell packaging method, a solar cell, and a solar array. Background Technology

[0002] Solar cells are commonly used in the aerospace field. On spacecraft, solar cells are the core components that directly convert solar energy into electrical energy, primarily powering satellites, spacecraft, and space stations. These solar cells mainly utilize the photovoltaic effect, where sunlight shines on the cell, photons excite electrons, creating a potential difference, and thus outputting direct current (DC).

[0003] Existing solar cells are mainly multilayer thin-film composite structures, comprising a substrate, a back electrode layer, a photovoltaic layer, a front electrode layer, and an anti-reflection layer, which are then encapsulated using encapsulation processes. The substrate primarily provides mechanical strength, fixing the cell to the solar panel's substrate. The back electrode layer, a conductive metal layer, serves as the negative electrode and provides structural support. The photovoltaic layer, the core of the cell, is typically a triple / multi-junction gallium arsenide or silicon-based semiconductor, utilizing the photovoltaic effect to convert light energy into electrical energy. The front electrode layer consists of metal grid lines (such as silver paste) used to collect photogenerated carriers and guide current. The anti-reflection layer reduces sunlight reflection and improves light absorption. To increase photovoltaic power generation, multiple solar cells can be arrayed, electrically connected via solder strips to form a cell string. Several solder strips are electrically connected to busbars, allowing the current generated by the cell array to be collected. This collected current is then converted into alternating current by an inverter and connected to the mains power grid.

[0004] Patent application No. 202511960423.2 discloses a solar cell and a photovoltaic module. The solar cell includes a substrate, a first charge transport layer, a perovskite active layer, an interface modification layer, a second charge transport layer, a buffer layer, and an electrode layer, sequentially stacked along its thickness direction. The solar cell can be electrically connected in a single sheet or in multiple segments to form multiple cell strings, which are then connected in series and / or parallel. The photovoltaic module may also include an encapsulation layer and a cover plate. The encapsulation layer covers the surface of the cell strings, and the cover plate covers the surface of the encapsulation layer away from the cell strings. The encapsulation layer can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene co-elastomer film, or a polyethylene terephthalate film; the cover plate can be a glass cover plate, a plastic cover plate, or other light-transmitting cover plate.

[0005] Current technologies for encapsulating solar cells mostly encapsulate the multilayer thin-film composite structure of the cells, while the solder ribbons, welding points, and busbars between the cell arrays are not encapsulated. However, the harsh space environment, including cosmic rays and low temperatures, can affect the operation of solar panels. The solder ribbons, welding points, busbars, and circuit connections in existing unencapsulated solar panels are exposed to the harsh external environment of space exploration. Space ultraviolet radiation, atomic oxygen, and thermal shock can directly affect these exposed locations, leading to low reliability, affecting the normal operation of the solar panels, shortening their lifespan, and making it difficult to meet the requirements of long-term operation. Summary of the Invention

[0006] The purpose of this invention is to address the technical problems of low reliability and short service life of existing solar arrays in the harsh environment of space, and to provide a solar cell encapsulation method, a solar cell, and a solar array.

[0007] To achieve the above objectives, the present invention specifically adopts the following technical solution: A method for encapsulating a solar cell, the solar cell comprising a cell array, solder ribbons, busbars, and an encapsulation layer, wherein the solder ribbons connect multiple cells in the cell array in series to form a cell string, and multiple solder ribbons are electrically connected to the busbars through solder joints; the encapsulation layer covers the cell array, the solder ribbons, and part of the busbars; the encapsulation steps of the solar cell are as follows: Step 1: Arrange the solar cells in an array and connect multiple solar cells in the array into a solar cell string by soldering ribbons. Multiple soldering ribbons are electrically connected to the busbars through soldering points. Step 2: Arrange the battery cells in the cavity of the molding mold and fix the battery cells in place; Step 3: Inject the encapsulation slurry into the cavity of the molding mold. The encapsulation slurry covers the battery cell array, solder ribbons, and part of the busbars. Step 4: Curing the encapsulation paste to form an encapsulation layer on the outside of the cell array, solder ribbons, and some busbars.

[0008] Furthermore, in step 2, before arranging the battery cells in the cavity of the molding mold, a transparent film is pre-placed in the cavity of the molding mold. The material of the transparent film is the same as that of the encapsulation paste, and the shape and size of the transparent film are adapted to the battery cells.

[0009] Furthermore, after placing a transparent film in advance, the cavity of the molding mold is evacuated to a vacuum environment.

[0010] Furthermore, the transparent film is made of polyimide, ethylene-tetrafluoroethylene copolymer, or polyethylene naphthalate.

[0011] Furthermore, in step 4, when curing the encapsulation slurry, the encapsulation slurry is first pre-cured at a first preset temperature, and then the pre-cured encapsulation slurry is cured and formed at a second preset temperature, wherein the second preset temperature is higher than the first preset temperature.

[0012] Furthermore, during the pre-curing of the encapsulation slurry, the molding die filled with the encapsulation slurry is placed in a vacuum oven and first kept at 60~80°C for 30~120 minutes to remove the solvent; then kept at 100~150°C for 30~60 minutes to achieve initial cross-linking and fix the shape.

[0013] Further, the pre-cured composite is transferred to a high-temperature oven and first kept at 160~200°C for 30~60 min to initiate the imidization reaction; then, it is kept at 250~300°C for 60~120 min to complete the main imidization.

[0014] Furthermore, during the heating process, the heating rate does not exceed 2°C / min.

[0015] A solar cell is prepared by encapsulating the solar cell using the aforementioned solar cell encapsulation method.

[0016] A solar array includes a solar cell module and a deployment mechanism.

[0017] The solar cell module uses the aforementioned solar cells; The unfolding mechanism is configured to switch the plurality of solar cells from a retracted state to an unfolded state, or vice versa.

[0018] The beneficial effects of this invention are as follows: 1. In this invention, a transparent material (polyimide material) is used to encapsulate the battery and circuit components. The substrate does not block the back of the battery cell and can still receive light, making full use of the photoelectric conversion area. Moreover, the encapsulation is completed in one go, making the overall weight of the encapsulation structure lighter and easier to transport in space. In addition, the solder joints and solder ribbons inside the battery are all covered inside, reducing the area of ​​the battery directly exposed to the external environment, improving the reliability of the battery in the harsh environment of space, and extending the battery life.

[0019] 2. In this invention, a transparent polyimide film is pre-placed inside the cavity of the molding mold. The battery cells, solder ribbons, and busbars can be supported inside the cavity of the mold without directly contacting the inner surface of the bottom of the cavity. The encapsulation layer has a better covering effect on the battery, improving the reliability of the battery in the harsh environment of space and increasing the service life of the battery in outer space.

[0020] 3. In this invention, the cavity of the molding mold is kept in a vacuum state when the encapsulation slurry is poured. On the one hand, this can ensure that the air bubbles in the slurry are completely discharged, ensuring that the solar cell array and battery module are completely and shape-preservingly encapsulated. On the other hand, vacuum drying can prevent solvent residue from forming gaps around the welding points, ultimately resulting in a better encapsulation effect on the battery, improving the reliability of the battery in the harsh environment of space, and increasing the service life of the battery in outer space.

[0021] 4. In this invention, the curing of the encapsulation slurry is carried out in two steps. The first step involves preliminary cross-linking of polyamic acid at a lower temperature to fix the shape, preventing rapid solvent evaporation that could cause blistering or cracking on the surface of the transparent polyimide slurry layer, and preventing solvent residue around the welding points from forming voids. The second step involves chemical conversion of polyamic acid to polyimide at a higher temperature, ultimately completing the imidization of the main body. This prevents oxidation of the battery cell electrodes or degradation of the antireflective layer, and prevents the curing shrinkage stress of the transparent polyimide slurry from causing microcracks in the battery cell or delamination of the interface between the transparent polyimide slurry layer and the battery cell. This improves the encapsulation effect, enhances the reliability of the battery in the harsh environment of space, and extends the battery's lifespan in outer space. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the solar cell of the present invention; Figure 2 for Figure 1 A sectional view along the A1-A2 direction; Figure 3 This is a schematic diagram of the solar panel structure of the present invention; Figure 4 This is a schematic diagram of the packaging process of the present invention; The attached figures are labeled as follows: 100-cell array, 110-cell, 120-welding ribbon, 125-welding point, 130-busbar, 140-bypass diode, 150-encapsulation layer, 310-soldering module, 320-deployment mechanism, 120a-positive electrode section, 120b-interconnection section, 120c-negative electrode section. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0024] Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Example 1 This embodiment provides a solar cell encapsulation method that uses a transparent material to encapsulate the cell. The substrate does not block the back of the cell and can still receive light, making full use of the photoelectric conversion area. The encapsulation is completed in one step, resulting in a lighter overall weight and easier space transportation. Furthermore, the solder joints and solder ribbons inside the cell are all encapsulated, reducing the area of ​​the cell directly exposed to the external environment and extending the cell's lifespan.

[0026] The solar cell is as follows Figure 1 As shown, it specifically includes a solar cell array, which is composed of a number of solar cells 110 arranged in an array. The solar cell 110 is the basic unit for completing photoelectric conversion, and it can be a crystalline silicon solar cell, a gallium arsenide solar cell, a perovskite solar cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or other types of solar cells.

[0027] The cell array also includes multiple solder ribbons 120 and multiple busbars 130. Each solder ribbon 120 is along a first direction (e.g., Figure 1 The busbar 130 extends in a horizontal direction (as shown in the image) to connect multiple battery cells 110 in series to form a battery string. The busbar 130 extends along a second direction (as shown in the image) intersecting the first direction. Figure 1 Extending vertically (in the middle) and electrically connected to corresponding solder strips 120 via multiple solder points 125. Although in Figure 1 Only 3 rows and 3 columns of solar cells 110 are shown in the solar cell array. However, it is understood that each solar cell array 100 may include more or fewer solar cells 110, depending on the power and voltage requirements of the solar cell array 100, as well as the rated output power and size of each solar cell 110. The number can be determined according to actual needs. Generally, the number of solar cells 110 in a battery string is positively correlated with the rated output voltage of the solar cell array 100, that is, they are connected in series to increase the rated output voltage; while the number of battery strings is positively correlated with the rated output power of the solar cell array 100, that is, they are connected in parallel to increase the rated output current.

[0028] like Figure 2As shown, taking the upper surface of the solar cell 110 as the negative electrode and the lower surface as the positive electrode as an example, the solder ribbon 120 may include a positive electrode section 120a, an interconnection section 120b, and a negative electrode section 120c. The positive electrode section 120a is connected to the positive electrode of the first solar cell 110 and largely overlaps with it; the interconnection section 120b connects the negative electrode of the first solar cell 110 to the positive electrode of the adjacent second solar cell 110; another interconnection section 120b connects the negative electrode of the second solar cell 110 to the positive electrode of the adjacent third solar cell 110; the negative electrode section 120c is connected to the negative electrode of the third solar cell 110 and largely overlaps with it. In this way, the solder ribbon 120 can achieve series connection of three or more solar cells 110. (See also...) Figure 1 The positive electrode sections 120a of the three battery strings are then connected to the positive electrode busbar 130 on the left side via corresponding solder joints 125; similarly, the negative electrode sections 120a of the three battery strings are then connected to the negative electrode busbar 130 on the right side via corresponding solder joints 125; thus, the three solar cell strings are connected in parallel. In this way, the scale of a solar cell array can be expanded compared to a single solar cell.

[0029] like Figure 1 , Figure 2 As shown, a bypass diode 140 is connected between each solder strip 120 and busbar 130. When a cell string or cell in the solar cell array 100 is shaded, it will prevent that cell string or cell from generating electricity normally. Simultaneously, due to the semiconductor characteristics of solar cells, the resistance of the shaded cell string or cell will significantly increase, thus consuming the energy of other normally generating cell strings or cells, which is also known as a load in the circuit. The operating temperature of these temporarily loading cell strings or cells will rise, potentially causing device damage. Therefore, in this embodiment, the bypass diode 140 can selectively allow current to bypass the shaded cell string or cell, effectively preventing hot spots and reducing the risk of device burnout due to hot spots. Furthermore, due to the unidirectional conduction characteristic of the diode, when the power of a cell string is insufficient, the bypass diode 140 can also bypass that cell string to prevent current from other cell strings from flowing back to it, thus avoiding component damage. It is understood that the circuit components of this application may also include other... Figure 1 The interconnecting circuits or electronic components not shown are not the innovation of this embodiment. They can be selected and applied by those skilled in the art according to actual needs without creative effort, and will not be described in detail here.

[0030] like Figure 1 , Figure 2 As shown, it also includes an encapsulation layer 150. For clarity, Figure 1The encapsulation layer 150 is shown with a dashed box. The encapsulation layer 150 is made of a transparent insulating material and is molded in one piece to simultaneously encapsulate the solar cell array and its connected circuit components (including solder ribbons 120, solder joints 125, busbars 130, and bypass diodes 140). Because the encapsulation layer 150 is formed of a transparent material, it does not block the propagation of sunlight, allowing the solar cell array to receive light from both sides, which improves the overall photoelectric conversion efficiency. Furthermore, in the solar cell array 100, except for the ends of the busbars 130 used for external connections which are directly exposed to the encapsulation layer 150, all other circuit components such as the intermediate busbars 130, bypass diodes 140, solder ribbons 120, and solder joints 125, as well as all the solar cells 110, are encapsulated as a whole by the encapsulation layer 150, achieving full-dimensional protection for the circuits and solar cells 110, thereby improving the reliability of the solar cell array 100.

[0031] Furthermore, the encapsulation layer 150 can be formed from a single transparent insulating material, eliminating the need for adhesives, thus reducing the risk of failure and lightening the weight of the solar array. This transparent insulating material can be transparent polyimide (CPI, Colorless Polyimide). Transparent polyimide is a type of colorless or highly transparent polyimide material. Through molecular structure design, it suppresses the charge-transfer complexes of traditional polyimides, thereby changing from yellow to transparent, while retaining the core advantages of traditional polyimides such as high temperature resistance, high flexibility, and low expansion. However, the material of the encapsulation layer 150 in this embodiment is not limited to transparent polyimide; other suitable transparent insulating materials such as ethylene-tetrafluoroethylene copolymer (ETFE) and polyethylene naphthalate can also be used.

[0032] In addition, the cell array 100 also includes a protective coating (not shown) disposed on the outer surface of the encapsulation layer 150. The protective coating may possess characteristics such as high light transmittance, resistance to environmental conditions, and strong chemical stability. Disposed on the outer surface of the encapsulation layer 150, it provides functions such as protection against proton oxygen, UV radiation, anti-reflection, and thermal protection. The protective coating may include inorganic oxide coatings and / or metal oxide coatings, such as silicon oxide, silicon nitride, aluminum oxide, and iron oxide.

[0033] Multiple Figure 1 The cell array 100 shown can be assembled to form a variety of desired battery devices, such as solar cells for use in space environments or any other suitable operating environment.

[0034] When using the above-mentioned encapsulation materials to encapsulate a battery, the specific encapsulation steps are as follows: Step 1: Arrange the battery cells 110 in an array, and connect multiple battery cells 110 in the battery cell array into a battery cell string by solder ribbons 120. Multiple solder ribbons 120 are electrically connected to the busbar 130 through soldering points 125.

[0035] like Figure 1 As shown, the cell array 100 includes multiple cells 110 arranged in an array, multiple solder ribbons 120, and multiple busbars 130. Each solder ribbon 120 is used to connect multiple cells 110 in series to form a cell string, and the busbars 130 are electrically connected to the multiple solder ribbons 120 via solder points 125.

[0036] Multiple solar cells 110 are interconnected into a cell string using solder ribbons 120 according to the design power and voltage requirements. Bypass diodes 140 are soldered at appropriate positions in the cell string to form a complete electrical functional unit. The solder ribbons 120 are then soldered to the busbar 130. It can be understood that the solar cell array 100 can be fabricated using various suitable methods.

[0037] Step 2: Arrange the battery cells 110 in the cavity of the molding mold and fix the battery cells 110.

[0038] The cell array 100 is arranged in the cavity of the molding mold according to the designed spacing and position, and the cell array 100 is precisely positioned by vacuum adsorption or temporary fixing to ensure that the position deviation of the cell 110 is controlled within the predetermined error (e.g., ±0.1 mm).

[0039] A number of transparent polyimide films are pre-placed in the cavity of the molding die. The size and shape of these films are roughly equivalent to that of a single solar cell 110, or alternatively, they can be roughly equivalent to or slightly larger than the shape and size of the entire solar cell array to be formed, so that the solar cell 110, multiple solder ribbons 120 and multiple busbars 130 included in the solar cell array can be supported in the cavity of the molding die without directly contacting the bottom inner surface of the cavity.

[0040] The molding die can also be designed with reserved channels for the encapsulation slurry flow and venting. Furthermore, the molding die is connected to a vacuum pump or similar vacuuming equipment via its venting channel (the structure and connection method of the channel and pump can be directly applied to existing technologies; those skilled in the art can directly select and apply them according to their needs without any creative effort), so that a vacuum environment can be formed in the chamber of the molding die. After the solar cell array is placed in the molding die, the vacuum environment can prevent the formation of gaps between the solar cell array and the bottom transparent polyimide film, thus avoiding residual air.

[0041] Step 3: Inject the encapsulation slurry into the cavity of the molding mold, and encapsulation slurry covers the battery cell array, solder ribbon 120 and part of the busbar 130.

[0042] The encapsulation paste can be a transparent polyimide paste (or ethylene-tetrafluoroethylene copolymer or polyethylene naphthalate), which is in a fluid state before curing. For example, the degassed transparent polyimide paste (i.e., in a polyamic acid precursor solution state) is poured into the cavity of the molding die under a vacuum environment. The vacuum environment eliminates air bubbles in the encapsulation paste and ensures that the encapsulation paste fully wets the complex geometry around the solar cell surface, grid gaps, bypass diodes, and solder joints. The amount of encapsulation paste poured can be precisely controlled according to the target thickness of the encapsulation layer 150. For example, the thickness of the encapsulation layer 150 on the upper surface of the cell 110 is 10~200µm, the thickness of the encapsulation layer 150 on the lower surface of the cell 110 is 10~200µm, and the local area of ​​the encapsulation layer 150 around the solder joint 125 and bypass diode 140 can be thickened to 500µm to enhance protection. It should be noted that the fluidity of the encapsulation slurry needs to be controlled during the pouring process. The fluidity of the slurry needs to be low enough to fill the gaps between the grid lines and the solder joint grooves, but also high enough to prevent the cells from shifting during the pouring process. In addition, the vacuum level is preferably below 100 Pa to ensure that air bubbles in the slurry are completely expelled. The pouring rate of the slurry needs to be slow and uniform to avoid impact that could cause microcracks in the cells.

[0043] When a transparent polyimide film is pre-placed inside the molding die cavity, the fluid encapsulation slurry can fully contact the solar cell array and battery module, and make full contact with the transparent polyimide film on its outer periphery, thereby ensuring that the solar cell array and battery module are completely and shape-conservingly encapsulated without any gaps or air bubbles.

[0044] Step 4: Curing the encapsulation paste to form an encapsulation layer 150 on the outside of the cell array, solder ribbon 120, and part of the busbar 130.

[0045] First, the encapsulation paste is pre-cured in a vacuum environment at a first preset temperature; then, the pre-cured encapsulation paste is cured and molded at a second preset temperature, which is higher than the first preset temperature. Specifically: First, the battery cell 110, after being filled with transparent polyimide slurry, is placed in a vacuum oven and pre-cured by heating according to a preset program. For example, it is first kept at 60-80°C for 30-120 minutes to remove most of the solvent; then kept at 100-150°C for 30-60 minutes to allow the polyamic acid to initially cross-link and fix its shape. After pre-curing, the position of the battery cell 110 is locked, and the transparent polyimide slurry is transformed into a gel state (i.e., the pre-cured composite), which can be demolded or transferred for high-temperature imidization. Preferably, in the above pre-curing process, the heating rate is controlled not to exceed 2°C / min throughout the heating process to avoid rapid solvent evaporation that could cause blistering or cracking on the surface of the transparent polyimide slurry layer, while vacuum drying can prevent solvent residue from forming voids around the welding points.

[0046] After pre-curing, a high-temperature imidization process is performed to solidify the transparent polyimide slurry. Specifically, the pre-cured composite can be transferred to a high-temperature oven for the chemical conversion of polyamic acid to polyimide; for example, the imidization reaction is initiated by holding the temperature at 160-200°C for 30-60 minutes, followed by holding it at 250-300°C for 60-120 minutes to complete the main imidization. Alternatively, the temperature can be held at 300-350°C for 30 minutes to further enhance crystallinity. It should be noted that the imidization temperature window must match the cell's tolerance temperature to avoid electrode oxidation or antireflective layer degradation. Controlling the heating rate is crucial to prevent microcracks in the cell or delamination at the interface between the transparent polyimide slurry layer and the cell caused by curing shrinkage stress. Preferably, the heating rate is controlled to not exceed 2°C / min throughout the entire heating process.

[0047] Example 2 Based on Example 1, after forming the encapsulation layer 150, a protective coating is formed on the outer surface of the encapsulation layer 150.

[0048] The protective coating can have the characteristics of high light transmittance, resistance to space environment and strong chemical stability. It is set on the outer surface of the encapsulation layer 150 to achieve functions such as anti-proton oxygen, anti-ultraviolet radiation, anti-reflection and thermal control protection.

[0049] Based on the space environment requirements of the target orbit where the solar cell array 100 is located, a protective coating is prepared on the outer surface of the cured encapsulation layer 150. For example, a metal oxide composite layer can be formed on the outer surface of the encapsulation layer 150 using a low-temperature sol-gel process as an ultraviolet reflective coating to reflect or absorb high-energy ultraviolet photons in the 200-400nm wavelength range. Alternatively, an inorganic oxide protective layer can be prepared using low-temperature physical vapor deposition as an atomic oxygen protective coating. A transparent conductive oxide coating can also be used as a thermal control coating to achieve active regulation of solar absorptivity and infrared emissivity. It should be noted that the preparation temperature of all protective coatings should not exceed 150°C to avoid thermal damage to the cured encapsulation layer 150 (e.g., transparent polyimide) and the solar cell 110.

[0050] Example 3 A solar cell is prepared by encapsulating the solar cell using the solar cell encapsulation method described in the above embodiments.

[0051] Example 4 A solar array includes a solar cell module 310 and a deployment mechanism 320.

[0052] The solar cell module 310 uses the aforementioned solar cell; The unfolding mechanism 320 is configured to switch the plurality of solar cells from a retracted state to an unfolded state, or vice versa.

[0053] like Figure 3 As shown, the deployment mechanism 320 is configured to switch the multiple solar cell modules 310 from a retracted state to an deployed state, or reversibly retract the deployed multiple solar cell modules 310 back into their retracted state. The multiple solar cell modules 310 can be pre-rolled into a cylindrical shape for easy transport, such as being carried by rockets or other aircraft during an air launch.

[0054] Accordingly, the deployment mechanism 320 can employ existing technologies, which can be selected and used by those skilled in the art according to their needs. It may include a roll-up beam and tensioning cables. The deployment mechanism 320 can be a foldable truss frame, with multiple solar cell modules 310 integrated with it. The foldable truss frame allows the multiple solar cell modules 310 to be converted from a folded state to an deployed state, for example, after the solar array is transported to a predetermined location in space and exposed to the space environment. It should be noted that this application does not limit the specific structure of the deployment mechanism 320; depending on the specific application scenario, the deployment mechanism 320 can have different deployment methods and frame support forms.

Claims

1. A method for encapsulating a solar cell, characterized in that: The solar cell includes a cell array, solder ribbons (120), busbars (130), and an encapsulation layer (150). The solder ribbons (120) connect multiple cells (110) in the cell array in series to form a cell string. Multiple solder ribbons (120) are electrically connected to the busbars (130) through solder joints (125). The encapsulation layer (150) covers the cell array, solder ribbons (120), and part of the busbars (130). The encapsulation steps of the solar cell are as follows: Step 1: Arrange the battery cells (110) in an array and connect multiple battery cells (110) in the battery cell array into a battery cell string by solder ribbons (120). Multiple solder ribbons (120) are electrically connected to the busbar (130) through soldering points (125). Step 2: Arrange the above-mentioned battery cells (110) in the cavity of the molding mold and fix the battery cells (110). Step 3: Inject the encapsulation slurry into the cavity of the molding mold. The encapsulation slurry covers the battery cell array, the solder ribbon (120), and part of the busbar (130). Step 4: Curing the encapsulation paste to form an encapsulation layer (150) on the outside of the cell array, solder ribbon (120) and part of the busbar (130).

2. The solar cell encapsulation method as described in claim 1, characterized in that: In step 2, before arranging the battery cell (110) in the cavity of the molding mold, a transparent film is placed in the cavity of the molding mold. The material of the transparent film is the same as that of the encapsulation paste, and the shape and size of the transparent film are compatible with the battery cell (110).

3. The solar cell encapsulation method as described in claim 2, characterized in that: After placing a transparent film in advance, the cavity of the molding mold is evacuated to a vacuum environment.

4. A solar cell encapsulation method as described in claim 2, characterized in that: The transparent film is made of polyimide, ethylene-tetrafluoroethylene copolymer, or polyethylene naphthalate.

5. A solar cell encapsulation method as described in claim 1, characterized in that: In step 4, when curing the encapsulation slurry, the encapsulation slurry is first pre-cured at a first preset temperature, and then the pre-cured encapsulation slurry is cured and formed at a second preset temperature. The second preset temperature is higher than the first preset temperature.

6. A solar cell encapsulation method as described in claim 5, characterized in that: When pre-curing the encapsulating slurry, the molding mold filled with the encapsulating slurry is placed in a vacuum oven and kept at 60~80°C for 30~120 minutes to remove the solvent; then kept at 100~150°C for 30~60 minutes to achieve initial cross-linking and fix the shape.

7. A solar cell encapsulation method as described in claim 6, characterized in that: The pre-cured composite was transferred to a high-temperature oven and kept at 160-200°C for 30-60 minutes to initiate the imidization reaction; then, it was kept at 250-300°C for 60-120 minutes to complete the main imidization.

8. A solar cell encapsulation method as described in claim 7, characterized in that: During the heating process, the heating rate shall not exceed 2°C / min.

9. A solar cell, characterized in that, The solar cell is prepared by encapsulation using the solar cell encapsulation method described in any one of claims 1-8.

10. A solar panel, characterized in that, Includes solar cell module (310) and deployment mechanism (320); The solar cell module (310) uses the solar cell described in claim 9; The unfolding mechanism (320) is configured to switch the plurality of solar cells from a folded state to an unfolded state, or vice versa.

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