How does the quality of high temperature adhesive tape affect the performance and life of photovoltaic modules?
As the core auxiliary material for the production and packaging of photovoltaic modules, the quality of high-temperature adhesive tape is directly related to the stability of the production process and the protective effect of the core components, and even fundamentally affects the photoelectric conversion efficiency and safety performance of photovoltaic modules through problems such as residual adhesive pollution, sealing failure and insulation damage, and finally determines the standard of the 25-year outdoor service life of modules. Inferior high-temperature adhesive tape will cause a series of cascading failures, while qualified special high-temperature adhesive tape for photovoltaic can provide key guarantee for the performance and service life of the module. From the two dimensions of positive guarantee and negative impact, this paper analyzes the specific impact on photovoltaic modules by core quality indicators, which fits the actual scene of photovoltaic production and outdoor use:
1. Qualified special high-temperature adhesive tape for photovoltaic: laying a solid foundation for the performance and life of modules.
The special high-temperature adhesive tape for photovoltaic needs to meet the five core quality standards of temperature resistance, no residual adhesive, weather resistance, insulation and environmental protection. Its high-quality performance will go through the whole process from production to outdoor use, ensuring stable performance and up-to-standard service life of components:
High temperature resistance up to standard (long-term 150℃/ short-term 200℃): It is suitable for the high-temperature and high-pressure working conditions of 130~180℃ for module lamination, and the adhesive tape does not soften, fall off or shrink, which can stably realize the functions of battery positioning, adhesive film overflow shielding, frame sealing, etc., to avoid module typesetting deviation and adhesive film pollution to glass/laminator due to adhesive tape failure, to ensure the production accuracy of the module and avoid packaging defects from the source; When used outdoors, the surface temperature of the module can reach 70~80℃ in summer, and the adhesive tape has no deformation and adhesive force attenuation, which continuously plays the role of insulation and protection.
No residual adhesive is peeled off, and the adhesive force is controllable: after the production process is completed, the adhesive tape is peeled off, and there is no adhesive layer residue on the surface of the assembly glass, back plate and battery sheet, so as to prevent the residual adhesive from blocking the grid line of the battery sheet, reduce the light transmittance of the glass, and ensure that the photoelectric conversion efficiency of the assembly is not attenuated; At the same time, the adhesive force is moderate, which will not cause displacement in production due to too weak adhesive force, nor will it pull the battery sheet and tear the back plate when peeling due to too strong adhesive force, thus preventing hidden faults such as cracking and back plate damage of the assembly.
Excellent weatherability (UV/high-low-temperature/high-humidity resistance): outdoor adhesive tapes (such as edge protection of components and junction box fixing) can withstand alternating high and low temperatures of-40℃~85℃, strong ultraviolet irradiation and high-humidity condensation environment, and will not age, powder or fall off after long-term use, and continue to play the role of sealing, insulation and fixing, so as to avoid water ingress, short circuit and fixation of components due to tape failure.
Insulation and mechanical strength meet the standards: volume resistivity ≥ 10Ω cm, dielectric strength ≥20kV/mm, which can effectively isolate the battery cell, metal terminal of junction box from the metal frame and backplane of the assembly, and prevent outdoor short circuit, electric leakage and other safety failures; At the same time, the tensile strength and tear resistance of the adhesive tape are up to standard, and it will not be damaged due to operation in production, and it will not be worn and broken outdoors due to sandstorm and strong wind, thus ensuring the continuous and effective protection effect.
Environmental protection and no release of harmful substances: the adhesive layer is halogen-free, formaldehyde-free, and volatile organic compounds (VOC), and does not release acidic and corrosive gases during high-temperature lamination, which will not pollute the EVA/POE film, avoid yellowing of the film and decline in adhesive performance, ensure the sealing and adhesive strength of the package layer of the module, and prevent core failures such as delamination and water ingress in the later stage of the module; At the same time, it will not corrode the battery sheet and metal frame, and avoid oxidation failure of internal components of the assembly.
Second, inferior high-temperature adhesive tape: it directly leads to the performance attenuation of components and greatly shortens the service life.
Inferior high-temperature adhesive tapes that are not specially used for photovoltaics will have hidden trouble in production due to quality defects such as insufficient temperature resistance, residual adhesive, poor weather resistance and substandard environmental protection. After outdoor use, they will quickly fail, causing a series of problems of components, which will eventually lead to a significant decline in performance and a life of far less than 25 years. The core negative effects are as follows:
The production process leads to packaging defects, which directly reduces the initial performance of components.
Insufficient temperature resistance: the adhesive tape softens, falls off and shrinks at high laminating temperature, which can not block the overflow of adhesive, resulting in the adhesion of EVA adhesive film to the laminator, pollution of the assembly glass, and the decrease of glass transmittance; Cell positioning failure, typesetting deviation, series-parallel circuit of components affected, and initial photoelectric conversion efficiency decreased by 5%~20%.
Residual glue/out-of-control adhesion: after peeling, the residual glue blocks the grid line of the battery and pollutes the glass, further reducing the light transmittance and power generation efficiency; When the adhesive force is too strong, the battery sheet is pulled when peeling, which causes the battery sheet to crack, and the crack expands during the use of the module, and the power continues to decay; Tearing the backboard leads to the damage of the protective layer of the backboard, which is easy to be oxidized by water in the later stage.
Poor mechanical strength: the adhesive tape is damaged during operation, which can't effectively protect the battery chip, and the solder spatter burns the silicon chip during welding, resulting in the battery chip being scrapped; When the sealing fails, the adhesive film overflows to the frame of the assembly during lamination, which affects the fit between the frame and the assembly and buries the hidden danger of water ingress.
The failure of insulation leads to the safety failure of the assembly, which directly leads to the failure of the insulation resistance of the inferior adhesive tape when it is shut down and scrapped. After outdoor use, the adhesive layer is aging and absorbs moisture, which can not isolate the metal parts, and it is easy to cause short circuit inside the assembly and leakage of the frame. In some cases, the assembly triggers grounding protection and stops power generation. In addition, it will lead to arc and fire, which will not only directly scrap the components, but also affect the surrounding photovoltaic arrays, causing major safety accidents and economic losses.
Poor weather resistance, rapid outdoor failure, causing multiple late failures of components. This is the core influence of inferior adhesive tape on the life of components. After 3~5 years of outdoor use, it will age, powder and fall off, causing a series of chain failures, and the life of components will be directly shortened to 5~10 years.
Sealing failure: the adhesive tape falls off, which leads to unprotected gaps at the edge of the module, junction box and backplane, rainwater and condensation seep through the gaps, and the battery cells and bus bars are oxidized and corroded, so that the power of the module is attenuated by more than 10% every year (the annual attenuation of normal qualified components is less than or equal to 0.5%), and finally the power generation capacity is completely lost.
Fixation failure: the junction box and electrode are loose due to adhesive tape falling off, and poor contact leads to virtual connection of components, resulting in a sudden drop in power generation efficiency; The edge protection of the module is invalid, and the glass and backboard are layered, which greatly reduces the impact resistance and is easy to be damaged by hail and sand.
Yellowing and delamination of film: harmful substances released by inferior tape at high temperature pollute EVA/POE film, which leads to rapid yellowing of film and decreased light transmittance; At the same time, the adhesive property of the adhesive film is weakened, and delamination and bubbles appear in the package layer of the module, which further aggravates the risk of water ingress.
Environmental protection is not up to standard, which will corrode the core components of the module and accelerate the internal failure. The inferior adhesive tape contains halogen and formaldehyde, or acid gas is released at high temperature, which will corrode the grid lines and bus bars of the battery, leading to grid line breakage, bus bar oxidation, module circuit disconnection and gradual loss of power generation capacity; At the same time, the metal frame is corroded, which causes the frame to rust and affects the structural stability of the assembly; It will also accelerate the aging of EVA film, make the package layer lose its sealing function, and form a vicious circle of "water inflow-oxidation-power attenuation".
Long-term pollution of residual glue makes it impossible to repair the inferior adhesive tape in the later maintenance of the module. The residual glue is a stubborn adhesive layer, which adheres to the surface of the battery, glass and backplane, and cannot be completely cleaned in the later operation and maintenance: the problem of residual glue blocking the grid line persists, and the power generation efficiency cannot be restored; Residual glue affects the bonding performance of new adhesive film and new adhesive tape during repair. Even if the damaged parts are repaired, the failure will occur again because of poor bonding, and the final components can only be scrapped and cannot be repaired.
Third, the core summary: the quality of high-temperature adhesive tape is the key guarantee for the "bottom line" of photovoltaic modules.
The 25-year outdoor life of photovoltaic modules depends on the performance matching of all components, such as battery chip, packaging film, backboard and auxiliary materials. Although high-temperature adhesive tape is an auxiliary material, it plays an irreplaceable role in the three key links of packaging accuracy, core component protection and outdoor sealing and insulation:
Qualified photovoltaic special high-temperature adhesive tape can ensure that the package of the module is defect-free from the production source, the initial photoelectric conversion efficiency reaches the standard, and it can continuously play the role of protection and sealing outdoors, providing a basic guarantee for the 25-year life of the module;
Inferior high-temperature adhesive tape will directly lead to substandard initial performance of components, hidden failures in production, and rapid outdoor failure. Finally, the power attenuation of components far exceeds the standard, the service life is greatly shortened, and even safety accidents are caused, resulting in a sharp increase in operation and maintenance costs and economic losses in the later period.
In short, the quality of high-temperature adhesive tape is not the icing on the cake, but an essential prerequisite for the stable performance and service life of photovoltaic modules. Choosing high-temperature adhesive tape dedicated for photovoltaic modules and meeting the national standard/line standard is one of the core links for photovoltaic module manufacturers to control product quality.
