A packaging process of a top con photovoltaic module

Abstract

The application discloses a kind of encapsulation processes of TOPCON photovoltaic module, comprising the following steps: the both sides of cell piece are coated with cell piece water-blocking coating;Transparent front film, adhesive film, prepreg, adhesive film, cell piece with water-blocking coating, adhesive film, back sheet are laid in turn;Each layer of material is bonded and encapsulated into a whole by heat pressing process;After encapsulation, according to the drawing, cut to the required size, install junction box;The cell piece of the application is protected by water-blocking glue and encapsulation material, forming double-layer protection inside and outside, and then more efficiently protecting the module, prolonging the service life of the module, solving the problem that high-efficiency water-blocking, lightweight flexibility and low cost cannot be notified to meet in the prior art.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module technology, specifically to a packaging process for TOPCON photovoltaic modules. Background Technology

[0002] As a core component of solar power generation, photovoltaic (PV) modules directly impact power generation efficiency and system stability. In recent years, with the rapid development of PV technology, TOPCON cells have gradually become one of the mainstream technologies due to their high efficiency and low degradation. However, PV modules are susceptible to moisture corrosion during long-term outdoor use, leading to performance degradation or even damage to the cells, severely affecting the module's lifespan and economic benefits. Furthermore, traditional single-glass and double-glass modules are relatively heavy, limiting their application in lightweight and flexible scenarios. Therefore, developing a PV module that combines high water-blocking performance with lightweight flexibility has become an important research direction in the current technological field.

[0003] In existing technologies, several solutions are typically used to address the moisture erosion problem of photovoltaic modules: one is to improve water-blocking performance by increasing the thickness of the encapsulation material (glass thickness) and using more expensive encapsulants with better water-blocking properties. However, this method increases the weight of the module, reduces its flexibility, and increases manufacturing costs. Therefore, while traditional encapsulation materials can provide a certain level of water-blocking performance, their large weight limits their application in lightweight applications. Furthermore, although high-cost water-blocking materials can improve water-blocking effects, their main drawback is that they cannot simultaneously meet the requirements of high-efficiency water blocking, lightweight flexibility, and low cost, which also hinders large-scale promotion. Summary of the Invention

[0004] This invention provides a TOPCON photovoltaic module encapsulation process in which the solar cells are protected by water-blocking adhesive and encapsulation materials, forming a double-layer protection, thereby more effectively protecting the module, extending the module's lifespan, and solving the problems of existing technologies failing to meet the requirements of high-efficiency water blocking, lightweight flexibility, and low cost.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a TOPCON photovoltaic module encapsulation process, characterized by comprising the following steps: S1. The solar cells are screened, then diced and welded using an existing string welding machine. Multiple solar cells are connected in series to form a battery string using interconnecting strips. S2. Perform EL test on the battery string, and after the EL test is completed, slowly pass the battery string through the glue tank filled with water-blocking glue with the conveyor belt to completely immerse the battery string. S3. The battery string wrapped with water-blocking adhesive then moves slowly to the drying area along the conveyor belt to dry and cure the water-blocking adhesive. At the same time, the matching busbar is also immersed in the adhesive tank and dried and cured. S4. Scrape off the water-blocking adhesive from the surface of the parts where the busbar and the interconnecting strip are welded together; S5. Use the first battery string carrier to arrange the battery strings, and then use the existing stacking welding machine to connect the battery strings into a battery cell assembly according to the drawings using the busbars. S6. After the tandem welding is completed, wrap the welded joint with water-blocking adhesive and dry the water-blocking adhesive again. S7. Lay a back film on the cell assembly, then lay a back sheet on the back film, and then cover the second cell string carrier on the back sheet and place it on the flipping device to flip the assembly 180°. S8. After the flipping is completed, remove the first battery string carrier, lay the front adhesive film on the upper side of the battery cell assembly, and perform EL test on the laid assembly. If the EL test is passed, lay a transparent front film on the front adhesive film. S9. The entire component is fed into the laminator for component encapsulation.

[0006] Preferably, both the first battery string carrier and the second battery string carrier are glass sheets.

[0007] Preferably, the following steps are included after step S9: S10. Trim the edges according to the drawing requirements to form a semi-finished component; S11. Scrape off the water-blocking adhesive at the welding position on the lead wire of the component, and weld the lead wire to the junction box.

[0008] Preferably, step S8 further includes laying a prepreg layer on the upper side of the front adhesive film, and then laying a front adhesive film on the prepreg layer.

[0009] Preferably, the module forms a double layer of water barrier through an outer encapsulation material and an inner water-blocking adhesive. Even if the outer encapsulation material is invaded by moisture, the inner water-blocking adhesive protects the solar cells.

[0010] Preferably, the prepreg layer is a glass fiber reinforced material.

[0011] Preferably, the water-blocking adhesive is made of polyurethane.

[0012] Compared with the prior art, the beneficial effects of the present invention are: By combining existing string welding machines with glue tanks and conveyor belts, water-blocking adhesive can be completely wrapped around the outside of the solar cells, achieving all-round water blocking. This meets the requirements of lightweight, flexible, and low-cost flexible photovoltaic modules. The process cost is low, and water blocking can also be achieved at the busbar and interconnect bar positions, extending the module life and thus increasing the benefits brought by the module. Even if a small amount of moisture enters, it will not cause corrosion to the solar cells. Attached Figure Description

[0013] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a structural diagram of the battery string of the present invention; Figure 3 This is a structural diagram of the battery cell assembly of the present invention; Figure 4 for Figure 3 Enlarged structural diagram at point B; Figure 5 for Figure 3 Enlarged structural diagram at point C; Figure 6 This is a partial cross-sectional view of the present invention; Figure 7 This is a comparison image of the DH1000-hour test before and after the component of the present invention without the water-blocking coating. Figure 8 This is a comparison image of the component of the present invention before and after the DH1000-hour test after the water-blocking coating was applied.

[0014] Figure label: 1. Battery string, 2. Interconnecting strip, 3. Battery cell, 4. Busbar, 5. Water-blocking adhesive, 6. Prepreg layer, 7. Transparent front film, 8. Backsheet. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0016] This invention aims to address the shortcomings of existing technologies that fail to adequately meet the requirements of high water resistance, lightweight flexibility, and low cost. For example... Figure 1-6 As shown, the following technical solution is provided: a TOPCON photovoltaic module encapsulation process, characterized by comprising the following steps: S1. The battery cells 3 are screened, then diced and welded using an existing stringer. Multiple battery cells 3 are connected in series to form a battery string 1 using interconnecting strips 2. The battery cell screening criteria are: photoelectric conversion efficiency ≥25.2% and microcrack detection accuracy ≤0.1mm. The dicing is carried out using laser cutting technology, with a cut roughness Ra≤1.6μm to avoid edge stress concentration that could cause the water-blocking adhesive to crack. S2. Perform EL test on the battery string, and after the EL test is completed, slowly pass the battery string 1 through the glue tank filled with water-blocking glue with the conveyor belt. The battery string 1 should be completely immersed for 1-3 seconds. S3. The battery string 1 wrapped with water-blocking adhesive then moves slowly to the drying area along the conveyor belt to dry and cure the water-blocking adhesive. At the same time, the matching busbar 4 is also placed into the adhesive tank for immersion and drying and curing. The water-blocking adhesive drying process is as follows: first, pre-dry at 60℃ for 10 minutes, then raise the temperature to 120℃ for curing for 30 minutes. The wind speed in the drying area is controlled at 2m / s to ensure that the adhesive layer is uniformly cured without bubbles. S4. Scrape off the water-blocking adhesive on the surface of the part where the busbar 4 and the interconnecting strip 2 are welded together; S5. Use the first battery string carrier to arrange the battery string 1, and then use the existing stacking welding machine to connect the battery string 1 into a battery cell assembly using the busbar 4 according to the drawing. S6. After the tandem welding is completed, wrap the welded joint with water-blocking adhesive 5 and dry the water-blocking adhesive 5 again. S7. Lay a back film on the cell assembly, and lay a back plate 8 on the back film. Then cover the second cell string carrier on the back plate 8 and place it on the flipping device to flip the assembly 180°. S8. After the flipping is completed, remove the first battery string carrier, lay the front adhesive film on the upper side of the battery cell assembly, and perform EL test on the laid assembly. If the EL test is passed, lay the transparent front film 7 on the front adhesive film. S9. The entire component is fed into the laminator for encapsulation. The lamination process parameters can be: temperature 145℃, pressure 0.8MPa, holding time 15min, and laminator vacuum degree ≤10Pa to avoid moisture residue during the encapsulation process.

[0017] When using the above technology, it is only necessary to modify the existing conventional production lines such as stringing machines and packaging machines, and add glue tanks and drying areas to complete the modification. The cost is relatively low and can meet the process requirements.

[0018] After the above-mentioned process steps, TOPCON photovoltaic modules can be formed. In this process, water-blocking adhesive is used to completely wrap the solar cells, including the front, back, and edges, forming a physical barrier layer. The water vapor transmission rate is reduced to below 0.01g / m² / day, which is significantly better than traditional EVA film (WVTR≈5-10g / m² / day). At the same time, the water-blocking adhesive is only 0.05mm thick, reducing the overall weight of the module by more than 35%, and meeting the mechanical requirement of flexible modules with a bending radius of ≤50cm.

[0019] according to Figure 2-5As shown, the solar cell module includes multiple cell strings 1 formed by connecting multiple solar cells 3 in series via interconnecting strips 4. The cell strings 1 are connected to each other via busbars 2 connected to the interconnecting strips 4. The connection between the cell strings 1 and the busbars 2 forms a lightweight and flexible photovoltaic module. The surfaces of both the interconnecting strips 4 and the busbars 2 are coated with water-blocking adhesive. This adhesive prevents water from entering at the connection points between the solar cells 3 and the interconnecting strips 4, completely blocking the water-oxygen corrosion path at the metal solder joints. After DH1000 testing, the solder joint resistance change rate was <0.5%, while in the control group (without water-blocking adhesive), solder joint corrosion resulted in a resistance increase >15%.

[0020] In this process, EL testing (Electroluminescence Testing) is an important technique for detecting internal defects in photovoltaic modules. It involves applying a forward bias voltage to the photovoltaic module, causing it to emit near-infrared light invisible to the naked eye. The emitted light is then captured by a specialized camera, providing a direct visual representation of the cell condition and defect distribution within the module.

[0021] The transparent front film 7 is made of ETFE material, which has good light transmittance and water resistance. The density of ETFE material is only 1.7g / cm³, which is 60% lighter than traditional glass. It has a light transmittance of 91% and also has anti-ultraviolet aging properties.

[0022] In the process, both the first and second battery string carriers are glass sheets, which can reduce contact with the battery cell assembly and ensure that the water-blocking adhesive on the surface of the battery cell assembly will not fall off.

[0023] Preferably, the following steps are included after step S9: S10. Trim the edges according to the drawing requirements to form a semi-finished component, which can be processed into different shapes and sizes as needed; S11. Scrape off the water-blocking adhesive at the welding position on the lead wire of the component, and weld the lead wire to the junction box. After scraping off the water-blocking adhesive when welding to the junction box, continue to fill the lead wire area outside the welding with water-blocking adhesive after the welding is completed.

[0024] Preferably, step S8 further includes laying a prepreg layer 6 on the upper side of the front adhesive film, and then laying another front adhesive film on the prepreg layer. The prepreg layer 6 can effectively support the flexible photovoltaic module. The prepreg layer 6 is made of glass fiber reinforced material, which is low in cost and can be firmly bonded to the adhesive film. The prepreg layer 6 adopts a unidirectional lay-up design, with a longitudinal tensile strength of up to 280MPa and a transverse flexural modulus ≤3GPa, enabling the module to withstand repeated bending with a radius ≥50mm.

[0025] As a specific embodiment: The transparent front film 7 is made of ETFE material with a thickness of 0.25mm; the adhesive film is made of EVA material with a thickness of 0.5mm; the prepreg layer 6 is made of glass fiber reinforced composite material with a thickness of 0.15-0.3mm; the water-blocking adhesive is made of polyurethane material with a thickness of 0.05mm; and the back plate 8 is a reinforced back plate with a thickness of 0.7mm.

[0026] After assembly, a DH1000-hour test was conducted. Conventional flexible modules showed obvious signs of moisture erosion in their photovoltaic cells (ELs) after DH1000 hours. However, the flexible photovoltaic module structure in this embodiment... Figure 8 Comparing the EL images, the flexible photovoltaic modules coated with water-blocking adhesive 2 showed no significant changes after DH1000 hours, while the modules without the water-blocking coating exhibited localized darkening of the cells. Figure 7 As shown.

[0027] According to the power attenuation comparison, the power of the module after applying the water-blocking coating decreased by only 0.05W (0.01%), which is almost unchanged, as shown in Table 1 below: Table 1 The power output of the module without the water-blocking coating decreased by 14.42W (2.61%). The water-blocking capacity of the module with the water-blocking coating is significantly higher than that of the module without the coating, as shown in Table 2 below: Table 2 In summary, existing technologies improve water-blocking performance by increasing glass thickness, but this increases the weight to 25 kg / m². This invention, through a composite design of 0.05 mm water-blocking adhesive and prepreg layer, reduces WVTR to 0.01 g / m² / day while weighing only 12 kg / m², achieving a dual breakthrough of "improved water-blocking performance and reduced weight".

[0028] Moreover, the cost of traditional high water-blocking adhesive film is about 80 yuan / m², while the cost of the polyurethane water-blocking adhesive of this invention is only 30 yuan / m². Furthermore, it does not require replacing the existing string welding machine, only adding an adhesive tank, resulting in very low modification costs. Therefore, the cost of single-component encapsulation is reduced by 25%.

[0029] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0030] Furthermore, in this invention, descriptions involving terms such as "primary," "secondary," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "primary" or "secondary" may explicitly or implicitly include at least one of that feature. In the description of this invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A packaging process for TOPCON photovoltaic modules, characterized in that, Includes the following steps: S1. The battery cells (3) are screened, then diced and welded using an existing string welding machine. Multiple battery cells (3) are connected in series to form a battery string (1) using interconnecting strips (2). S2. Perform EL test on the battery string, and after the EL test is completed, slowly pass the battery string (1) through the glue tank filled with water-blocking glue with the conveyor belt to completely immerse the battery string (1). S3. The battery string (1) wrapped with water-blocking adhesive is then slowly moved to the drying area by the conveyor belt to dry and cure the water-blocking adhesive. At the same time, the matching busbar (4) is also placed into the adhesive tank for immersion and drying and curing. S4. Scrape off the water-blocking adhesive on the surface of the part where the busbar (4) and the interconnecting strip (2) are welded together; S5. Use the first battery string carrier to arrange the battery string (1), and then use the existing stacking welding machine to connect the battery string (1) into a battery cell assembly using the busbar (4) according to the drawing. S6. After the tandem welding is completed, wrap the welded joint with water-blocking adhesive (5) and dry the water-blocking adhesive (5) again. S7. Lay a back film on the battery cell assembly and lay a back plate (8) on the back film. Then cover the second battery string carrier on the back plate (8) and place it on the flipping device to flip the assembly 180°. S8. After the flipping is completed, remove the first battery string carrier, lay the front adhesive film on the upper side of the battery cell assembly, and perform EL test on the laid assembly. If the EL test is passed, lay a transparent front film on the front adhesive film (7). S9. The entire component is fed into the laminator for component encapsulation.

2. The encapsulation process of the TOPCON photovoltaic module according to claim 1, characterized in that: Both the first and second battery string carriers are glass sheets.

3. The encapsulation process for TOPCON photovoltaic modules according to claim 2, characterized in that: Step S9 is followed by the following steps: S10. Trim the edges according to the drawing requirements to form a semi-finished component; S11. Scrape off the water-blocking adhesive at the welding position on the lead wire of the component, and weld the lead wire to the junction box.

4. The encapsulation process of the TOPCON photovoltaic module according to claim 1, characterized in that: Step S8 also includes laying a prepreg layer (6) on the upper side of the front adhesive film, and then laying a front adhesive film on the prepreg layer (6).

5. The encapsulation process for TOPCON photovoltaic modules according to claim 4, characterized in that: The prepreg layer (6) is a glass fiber reinforced material.

6. The encapsulation process for TOPCON photovoltaic modules according to any one of claims 1-5, characterized in that: The water-blocking adhesive (5) is made of polyurethane.

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