Pub Date : 2025-02-20DOI: 10.1109/JPHOTOV.2025.3540329
{"title":"Announcing an IEEE/Optica Publishing Group Journal of Lightwave Technology Specail Issue","authors":"","doi":"10.1109/JPHOTOV.2025.3540329","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3540329","url":null,"abstract":"","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"377-377"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10897244","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-20DOI: 10.1109/JPHOTOV.2025.3537263
{"title":"IEEE Journal of Photovoltaics Information for Authors","authors":"","doi":"10.1109/JPHOTOV.2025.3537263","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3537263","url":null,"abstract":"","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"C3-C3"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10897242","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1109/JPHOTOV.2025.3539292
Marco Nicoletto;Davide Panizzon;Alessandro Caria;Nicola Trivellin;Carlo De Santi;Matteo Buffolo;Gaudenzio Meneghesso;Enrico Zanoni;Matteo Meneghini
Most photovoltaic (PV) modules are guaranteed for 25–30 years. However, severe climatic events, particularly hail, can lead premature damage. In this article, a residential PV system in Padova, Italy, was studied after exposure to a severe storm with hailstones up to 16 cm in diameter, which is more than two times larger than the standard size of test stones employed for module validation (7.5 cm, as per IEC 61215-2-2021). The goals are: 1) to demonstrate the relevance of hail testing beyond what currently required by the standards; 2) to demonstrate the presence of latent damage even in the absence of broken glass or of reduced performance; and 3) to discuss the associated risks. Forward bias electroluminescence (EL) and infrared (IR) radiation investigations were conducted in dark to minimize the impact of environmental influences. In the worst case, complete glass breakage results in solar cell fragmentation, which induces nonuniformity in current flow and thermal radiation, increasing losses, compromising electrical insulation, and requiring immediate replacement. In addition, dark and outdoor light current–voltage characteristics reveal significant decrease in output power, as well as increased leakage current. Remarkably, latent or invisible damage, detectable by reduced EL intensity and higher IR radiation, poses safety issues even in modules whose protective glass withstood the mechanical impact of hail. Modules with intact glass exhibit a decreased shunt resistance, with a negligible reduction in the output power with respect to a completely intact module. The results underline the necessity of inspecting the entire PV system following hailstorms, to detect any latent damages and promptly replace the damaged modules, even in the absence of glass breakage or reduction in the output power, to ensure long-term reliability.
{"title":"Hail Damage Investigation in Heterojunction Silicon Photovoltaic Modules: A Real-World Case Study","authors":"Marco Nicoletto;Davide Panizzon;Alessandro Caria;Nicola Trivellin;Carlo De Santi;Matteo Buffolo;Gaudenzio Meneghesso;Enrico Zanoni;Matteo Meneghini","doi":"10.1109/JPHOTOV.2025.3539292","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3539292","url":null,"abstract":"Most photovoltaic (PV) modules are guaranteed for 25–30 years. However, severe climatic events, particularly hail, can lead premature damage. In this article, a residential PV system in Padova, Italy, was studied after exposure to a severe storm with hailstones up to 16 cm in diameter, which is more than two times larger than the standard size of test stones employed for module validation (7.5 cm, as per IEC 61215-2-2021). The goals are: 1) to demonstrate the relevance of hail testing beyond what currently required by the standards; 2) to demonstrate the presence of latent damage even in the absence of broken glass or of reduced performance; and 3) to discuss the associated risks. Forward bias electroluminescence (EL) and infrared (IR) radiation investigations were conducted in dark to minimize the impact of environmental influences. In the worst case, complete glass breakage results in solar cell fragmentation, which induces nonuniformity in current flow and thermal radiation, increasing losses, compromising electrical insulation, and requiring immediate replacement. In addition, dark and outdoor light current–voltage characteristics reveal significant decrease in output power, as well as increased leakage current. Remarkably, latent or invisible damage, detectable by reduced EL intensity and higher IR radiation, poses safety issues even in modules whose protective glass withstood the mechanical impact of hail. Modules with intact glass exhibit a decreased shunt resistance, with a negligible reduction in the output power with respect to a completely intact module. The results underline the necessity of inspecting the entire PV system following hailstorms, to detect any latent damages and promptly replace the damaged modules, even in the absence of glass breakage or reduction in the output power, to ensure long-term reliability.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 3","pages":"478-483"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1109/JPHOTOV.2025.3539319
Lelia Deville;Clifford W. Hansen;Kevin S. Anderson;Terrence L. Chambers;Marios Theristis
In this article, we recommend methods to translate parameters between the PVsyst and California Energy Commission (CEC) single-diode models. Translation adds flexibility to photovoltaic performance modeling by enabling the use of the CEC database with the PVsyst model and PVsyst Panneau Solaire files in the CEC model. We compare three approaches for translation and evaluate agreement between models using 21 unique modules of monocrystalline and polycrystalline silicon technologies and six climate datasets. The recommended approach yields the lowest normalized root-mean-square error for all module technologies, never exceeding 0.58% of rated power. Annual energy yields agree within 1.09% for all modules when using the optimization method. The recommended method will be proposed for inclusion in pvlib-python.
{"title":"Parameter Translation for Photovoltaic Single-Diode Models","authors":"Lelia Deville;Clifford W. Hansen;Kevin S. Anderson;Terrence L. Chambers;Marios Theristis","doi":"10.1109/JPHOTOV.2025.3539319","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3539319","url":null,"abstract":"In this article, we recommend methods to translate parameters between the PVsyst and California Energy Commission (CEC) single-diode models. Translation adds flexibility to photovoltaic performance modeling by enabling the use of the CEC database with the PVsyst model and PVsyst <italic>Panneau Solaire</i> files in the CEC model. We compare three approaches for translation and evaluate agreement between models using 21 unique modules of monocrystalline and polycrystalline silicon technologies and six climate datasets. The recommended approach yields the lowest normalized root-mean-square error for all module technologies, never exceeding 0.58% of rated power. Annual energy yields agree within 1.09% for all modules when using the optimization method. The recommended method will be proposed for inclusion in <italic>pvlib-python</i>.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 3","pages":"451-457"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10893713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1109/JPHOTOV.2025.3539294
Adrienne L. Blum;Harrison W. Wilterdink;Ronald A. Sinton
For decades, excess carrier recombination lifetime measurements using an eddy current photoconductance sensor have been essential in characterizing the quality of silicon photovoltaic samples prior to metallization. Key metrics reported from the analysis of these measurements include injection-dependent excess carrier recombination lifetime, emitter saturation current density, bulk lifetime, and the implied current–voltage curve. These metrics are crucial for process control, optimization, and technological advancements in photovoltaic research and development, as well as production. As modern high-efficiency cell designs increasingly rely on precise determination of these metrics, it is important to quantify their uncertainty due to all factors; this study specifically examines their sensitivity to uncertainties in the sample-specific input parameters required for their reporting. Overall, results with a high level of confidence, including less than 1-fA/cm2 uncertainty in emitter saturation current density and less than 1-mV uncertainty in implied ${V}_{mathrm{oc}}$, can be achieved with knowledge of the input thickness and substrate resistivity beyond what is specified on a wafer specification sheet.
几十年来，使用涡流光电导传感器测量多余载流子复合寿命对于表征金属化之前硅光伏样品的质量至关重要。分析这些测量结果的关键指标包括注入相关的多余载流子复合寿命、发射极饱和电流密度、体寿命和隐含的电流-电压曲线。这些指标对于光伏研发和生产的过程控制、优化和技术进步至关重要。由于现代高效电池设计越来越依赖于这些指标的精确测定，因此量化所有因素造成的不确定性非常重要；本研究特别检查了他们对报告所需的样本特定输入参数的不确定性的敏感性。总体而言，通过了解输入厚度和衬底电阻率，可以获得高置信度的结果，包括发射极饱和电流密度小于1 fa /cm2的不确定性和隐含的${V}_{ maththrm {oc}}$小于1 mv的不确定性。
{"title":"Sensitivity Analysis of Eddy Current Excess Carrier Recombination Lifetime Measurements Due to Input Parameter Uncertainty","authors":"Adrienne L. Blum;Harrison W. Wilterdink;Ronald A. Sinton","doi":"10.1109/JPHOTOV.2025.3539294","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3539294","url":null,"abstract":"For decades, excess carrier recombination lifetime measurements using an eddy current photoconductance sensor have been essential in characterizing the quality of silicon photovoltaic samples prior to metallization. Key metrics reported from the analysis of these measurements include injection-dependent excess carrier recombination lifetime, emitter saturation current density, bulk lifetime, and the implied current–voltage curve. These metrics are crucial for process control, optimization, and technological advancements in photovoltaic research and development, as well as production. As modern high-efficiency cell designs increasingly rely on precise determination of these metrics, it is important to quantify their uncertainty due to all factors; this study specifically examines their sensitivity to uncertainties in the sample-specific input parameters required for their reporting. Overall, results with a high level of confidence, including less than 1-fA/cm<sup>2</sup> uncertainty in emitter saturation current density and less than 1-mV uncertainty in implied <inline-formula><tex-math>${V}_{mathrm{oc}}$</tex-math></inline-formula>, can be achieved with knowledge of the input thickness and substrate resistivity beyond what is specified on a wafer specification sheet.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 3","pages":"393-399"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10893710","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Top-performing single-junction and two-terminal tandem devices that include at least one polycrystalline cell are compared with each other and their ideal limits. The parameters of open-circuit voltage, short-circuit current, and fill-factor are individually compared to the Shockley–Queisser limit to investigate where different technologies have room to improve. Technologies, such as silicon and cadmium telluride have the most room for improvement in open-circuit voltage currently utilizing 87% and 81% of their maxima, respectively. Detailed diode and fill-factor loss analysis is presented for single-junction devices to give further insight on how they compare and where efficiency is lost. Single-crystal technologies demonstrate a fill-factor closer to the Shockley–Queisser limit than polycrystalline devices. The high diode quality factor of polycrystalline devices is the leading cause of the decreased fill-factor. Similar analysis on tandem cells with at least one thin-film cell shows that although their efficiency exceeds that of the single-junction cells, the fraction of their ideal efficiency is smaller. By comparing parameters to the Shockley–Queisser limit, it becomes clearer where certain technologies have the potential for improvement.
{"title":"Top-Performing Photovoltaic Cells Compared to the Shockley–Queisser Limit","authors":"Camden Kasik;Marko Jošt;Ishwor Khatri;Marko Topič;James Sites","doi":"10.1109/JPHOTOV.2025.3533883","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3533883","url":null,"abstract":"Top-performing single-junction and two-terminal tandem devices that include at least one polycrystalline cell are compared with each other and their ideal limits. The parameters of open-circuit voltage, short-circuit current, and fill-factor are individually compared to the Shockley–Queisser limit to investigate where different technologies have room to improve. Technologies, such as silicon and cadmium telluride have the most room for improvement in open-circuit voltage currently utilizing 87% and 81% of their maxima, respectively. Detailed diode and fill-factor loss analysis is presented for single-junction devices to give further insight on how they compare and where efficiency is lost. Single-crystal technologies demonstrate a fill-factor closer to the Shockley–Queisser limit than polycrystalline devices. The high diode quality factor of polycrystalline devices is the leading cause of the decreased fill-factor. Similar analysis on tandem cells with at least one thin-film cell shows that although their efficiency exceeds that of the single-junction cells, the fraction of their ideal efficiency is smaller. By comparing parameters to the Shockley–Queisser limit, it becomes clearer where certain technologies have the potential for improvement.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"268-273"},"PeriodicalIF":2.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1109/JPHOTOV.2025.3531052
Max Liggett;Dylan J. Colvin;Andrew Ballen;Manjunath Matam;Hubert P. Seigneur;Mengjie Li;Andrew M. Gabor;Philip J. Knodle;Craig J. Neal;Sudipta Seal;Daniel Riley;Bruce H. King;Peter Michael;Laura S. Bruckman;Roger H. French;Kristopher O. Davis
This work investigates several photovoltaic (PV) modules that have shown signs of metal contact corrosion due to field exposure in a hot and humid climate. This includes two multicrystalline silicon aluminum back surface field systems with 10 and 14 years of exposure and one monocrystalline silicon passivated emitter and rear cell system with four years of exposure. A comprehensive, multiscale characterization process is used to evaluate these PV modules in great detail. Current–voltage ($I-V$), Suns-$V_{text{OC}}$ measurements, electroluminescence imaging, infrared imaging, and ultraviolet fluorescence imaging were performed, and locations of interest were cored and analyzed using cross-sectional scanning electron microscopy (SEM). A rigorous, quantitative analysis procedure for the cross-sectional SEM images is proposed and implemented. Careful characterization does reveal that some of these PV modules do indeed exhibit the same classic signs of acetic-acid-based corrosion of the glass frit that is present at the silver/silicon interface, which have been observed previously in PV modules exposed to damp heat in an environmental chamber.
{"title":"Characterization of Field-Exposed Photovoltaic Modules Featuring Signs of Contact Degradation","authors":"Max Liggett;Dylan J. Colvin;Andrew Ballen;Manjunath Matam;Hubert P. Seigneur;Mengjie Li;Andrew M. Gabor;Philip J. Knodle;Craig J. Neal;Sudipta Seal;Daniel Riley;Bruce H. King;Peter Michael;Laura S. Bruckman;Roger H. French;Kristopher O. Davis","doi":"10.1109/JPHOTOV.2025.3531052","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3531052","url":null,"abstract":"This work investigates several photovoltaic (PV) modules that have shown signs of metal contact corrosion due to field exposure in a hot and humid climate. This includes two multicrystalline silicon aluminum back surface field systems with 10 and 14 years of exposure and one monocrystalline silicon passivated emitter and rear cell system with four years of exposure. A comprehensive, multiscale characterization process is used to evaluate these PV modules in great detail. Current–voltage (<inline-formula><tex-math>$I-V$</tex-math></inline-formula>), Suns-<inline-formula><tex-math>$V_{text{OC}}$</tex-math></inline-formula> measurements, electroluminescence imaging, infrared imaging, and ultraviolet fluorescence imaging were performed, and locations of interest were cored and analyzed using cross-sectional scanning electron microscopy (SEM). A rigorous, quantitative analysis procedure for the cross-sectional SEM images is proposed and implemented. Careful characterization does reveal that some of these PV modules do indeed exhibit the same classic signs of acetic-acid-based corrosion of the glass frit that is present at the silver/silicon interface, which have been observed previously in PV modules exposed to damp heat in an environmental chamber.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"233-243"},"PeriodicalIF":2.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1109/JPHOTOV.2025.3530001
Ali Alhejab;Muhammad Abbasi;Shehab Ahmed
Photovoltaic (PV) energy systems are becoming an important source of sustainable energy. However, undiscovered faults within these systems may cause significant efficiency reduction. Localizing these faults to the module level is important for a quick fault diagnosis and maintaining the overall system efficiency. This article presents a novel method to localize intrastring, line-ground, cross-string, and partial shading faults in an $N$ × $M$ PV system down to the module level. The approach utilizes a single voltage sensor in the combiner box of the PV system and $lceil N/2 rceil$ bypass switches per string to bypass the connected PV modules during faults. The technique initially relies on identifying the faulty string. Once this string is determined, the voltage associated with each module in that string is found. Each module's voltage in that string is obtained by measuring the string voltage after bypassing each module corresponding to an activated switch. Subsequently, the resulting linear equations are solved to obtain the voltage of each module in the faulty string. The technique is verified using simulation and an experimental setup for a 5 x 4 small-size PV system. Experimental and simulation results demonstrate that the technique can accurately localize faulty modules with only $N$ voltage samples of the faulty string. The proposed method is robust to variations in the maximum power point tracking algorithm, ensuring faults are localized effectively in real-time.
{"title":"A Single Voltage Sensor Bypass Switch-Based Photovoltaic Fault Localization","authors":"Ali Alhejab;Muhammad Abbasi;Shehab Ahmed","doi":"10.1109/JPHOTOV.2025.3530001","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3530001","url":null,"abstract":"Photovoltaic (PV) energy systems are becoming an important source of sustainable energy. However, undiscovered faults within these systems may cause significant efficiency reduction. Localizing these faults to the module level is important for a quick fault diagnosis and maintaining the overall system efficiency. This article presents a novel method to localize intrastring, line-ground, cross-string, and partial shading faults in an <inline-formula><tex-math>$N$</tex-math></inline-formula> × <inline-formula><tex-math>$M$</tex-math></inline-formula> PV system down to the module level. The approach utilizes a single voltage sensor in the combiner box of the PV system and <inline-formula><tex-math>$lceil N/2 rceil$</tex-math></inline-formula> bypass switches per string to bypass the connected PV modules during faults. The technique initially relies on identifying the faulty string. Once this string is determined, the voltage associated with each module in that string is found. Each module's voltage in that string is obtained by measuring the string voltage after bypassing each module corresponding to an activated switch. Subsequently, the resulting linear equations are solved to obtain the voltage of each module in the faulty string. The technique is verified using simulation and an experimental setup for a 5 x 4 small-size PV system. Experimental and simulation results demonstrate that the technique can accurately localize faulty modules with only <inline-formula><tex-math>$N$</tex-math></inline-formula> voltage samples of the faulty string. The proposed method is robust to variations in the maximum power point tracking algorithm, ensuring faults are localized effectively in real-time.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"362-372"},"PeriodicalIF":2.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reducing the silver consumption of photovoltaics (PV) is a major aspect in recent solar cell research. For bifacial PERC+ solar cells silver is used for the front contact. On the rear side aluminum metallization provides the contact to the silicon. The native oxide of aluminum prohibits a standard soldering process. Therefore, rear side silver pads are typically used for the cell-to-cell interconnections with copper wires. Silver can be avoided when using ultrasonic soldering for wetting the aluminum metallization to form tin solder pads. We demonstrate mechanically stable soldering of interconnects to the silver-free solder pads with a median adhesion up to 3 N/mm. We observe a penetration of the native aluminum oxide layer by the ultrasonic tinning process and the formation of metal-to-metal contacts from the aluminum to the solder. Resistance measurements demonstrate a reduced series resistance of the ultrasonically prepared contact when compared with using silver pads. For PERC+ cells, we can thus fully avoid rear side silver pads for a standard stringing process to reduce the silver consumption by 20%–40%. We fabricate mini modules that reach the same efficiency as reference modules with standard silver pads on the rear. The efficiency degradation of the modules with the ultrasonic interconnection is less than 3.6% after 200 humidity-freeze cycles and less than 2.2% after 600 temperature cycles.
{"title":"Ultrasonic Tinning of Al Busbars for a Silver-Free Rear Side on Bifacial Silicon Solar Cells","authors":"Malte Brinkmann;Thomas Daschinger;Rolf Brendel;Henning Schulte-Huxel","doi":"10.1109/JPHOTOV.2025.3533901","DOIUrl":"https://doi.org/10.1109/JPHOTOV.2025.3533901","url":null,"abstract":"Reducing the silver consumption of photovoltaics (PV) is a major aspect in recent solar cell research. For bifacial PERC+ solar cells silver is used for the front contact. On the rear side aluminum metallization provides the contact to the silicon. The native oxide of aluminum prohibits a standard soldering process. Therefore, rear side silver pads are typically used for the cell-to-cell interconnections with copper wires. Silver can be avoided when using ultrasonic soldering for wetting the aluminum metallization to form tin solder pads. We demonstrate mechanically stable soldering of interconnects to the silver-free solder pads with a median adhesion up to 3 N/mm. We observe a penetration of the native aluminum oxide layer by the ultrasonic tinning process and the formation of metal-to-metal contacts from the aluminum to the solder. Resistance measurements demonstrate a reduced series resistance of the ultrasonically prepared contact when compared with using silver pads. For PERC+ cells, we can thus fully avoid rear side silver pads for a standard stringing process to reduce the silver consumption by 20%–40%. We fabricate mini modules that reach the same efficiency as reference modules with standard silver pads on the rear. The efficiency degradation of the modules with the ultrasonic interconnection is less than 3.6% after 200 humidity-freeze cycles and less than 2.2% after 600 temperature cycles.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"15 2","pages":"244-251"},"PeriodicalIF":2.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/JPHOTOV.2024.3519616
David Quispe;Brendan Eng;Mijung Kim;Brian J. Coppa;Minjoo L. Lee;Zachary C. Holman
The parasitic absorption of visible light in amorphous silicon layers can result in a short-circuit current density (Jsc) loss of up to 2 mA/cm2 for silicon heterojunction solar cells. To mitigate this issue, we explore the potential for polycrystalline Al0.25Ga0.75P and Al0.9Ga0.1As, both nonepitaxially deposited at 250 °C, to enable high Jsc while serving as alternative hole contacts to p-type amorphous silicon [a-Si:H(p)]. Using a suite of device characterization methods, we investigate how the passivation changes with the deposition of these III–V materials and their degree of hole selectivity. We identify that both Al0.25Ga0.75P and Al0.9Ga0.1As can still enable high implied open-circuit voltages >720 mV; however, they are not hole selective enough to enable high open-circuit voltage and fill factor. Ultimately, the best performing solar cells are limited to 9.6% and 10.8% efficiency with a nominal 5 nm of Al0.25Ga0.75P and a measured 13 nm of Al0.9Ga0.1As, respectively. However, both cells demonstrate higher Jsc than a reference cell with a-Si:H(p) that has a similar nominal thickness.
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