• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.77-83
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• 2005

The verified thermal efficiency, thermal capacity confirmed the effects of the cooling system. Therefore, it is useful for preventing the PV cell temperature rising when solar radiation accumulates in summer. When adopting a hybrid panel for the BIPV system, the affected areas include the vertical outside walls facing the south, southeast, and southwest on the curtain walls excluding windows. The standards on replace aluminum panel which were the popular exterior material were investigated, Designing practice made sure that it could be manufactured in various sizes, and confirmed the most proper method to install a hybrid panel in the BIPV system.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.108-112
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• 2012

Crystalline silicon solar cell remains the major player in the photovoltaic marketplace with 90 % of the market, despite the development of a variety of thin film technologies. Silicon's excellent efficiency, stability, material abundance and low toxicity have helped to maintain its position of dominance. However, the cost of silicon photovoltaic remains a major barrier to reducing the cost of silicon photovoltaics. Using the crystalline silicon wafer with thinner thickness is the promising way for cost and material reduction in the solar cell production. However, the thinner thickness of silicon wafer is, the worse bow phenomenon is induced. The bow phenomenon is observed when two or more layers of materials of different temperature expansion coefficiencies are in contact, in this case silicon and aluminum. In this paper, the solar cells were fabricated with different thicknesses of Al layer in order to reduce the bow phenomenon. With lower paste applications, we observed that the bow could be reduced by up to 40% of the largest value with 130 micron thickness of the wafer even though the conversion efficiency decrease of 0.5 % occurred. Since the bowed wafers lead to unacceptable yield losses during the module construction, the reduction of bow is indispensable on thin crystalline silicon solar cell. In this work, we have studied on the counterbalance between the bow and conversion efficiency and also suggest the formation of enough back surface field (BSF) with thinner Al paste application.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.98-104
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• 2014

Photovoltaic (PV) cell is considered as one of the finest ways to utilize the solar power. A study of improving solar cell's efficiency is important because the lifetime of solar cell is determined by photovoltaic module technology. Therefore, oxidation (and/or corrosion) of solder materials will be one of the primary yield and long-term reliability risk factor. Recently, the development of lead-free solder alloy has been done actively about lead-free solder alloys of the thermodynamic and mechanical properties. However, the oxidation behavior have rarely been investigated In this study, the oxidations of 60 wt% Sn-40 wt% Pb, 62 wt% Sn-36 wt% Pb -2 wt% Ag, 50wt% Sn-48 wt% Bi-2 wt% Ag alloys for the interconnect ribbon after exposure in atmosphere at $100^{\circ}C$ for several times were investigated. The wettability of 62 wt% Sn-36 wt% Pb-2 wt% Ag and 50 wt% Sn-48 wt% Bi-2 wt% Ag solders was also studied to compare with that of 60 wt% Sn-40 wt% Pb alloy. The results howed that the zero cross time and the wetting time of 50 wt% Sn-48 wt% Bi-2 wt% Ag solder were better than other two samples. The surface of tested samples was analyzed by XPS. The XPS result showed that in all samples, SnO grew first and then the mixture of SnO and $SnO_2$ was detected. $SnO_2$ grew predominantly for the long time aging. Moreover XPS depth profile analysis has found surface enrichment of tin oxide.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 전문대학교육위원
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• pp.110-113
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• 2004

PV model is presented based on the shockley diode equation. The simple model has a photo-current source, an single diode junction and a series resistance and includes temperature dependences. An accurate PV module electrical model is presented, matching with boost converter MPPT strategy and demosnstarted in Matlab for a typical general purpose solar cell. Given solar insolation and temperature, the model returns current vector and MPP.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2008년도 제34회 동계학술대회 초록집
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• pp.80-80
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• 2008

• 한국산학기술학회논문지
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• 제13권10호
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• pp.4733-4739
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• 2012

본 논문에서는 태양과 태양전지 모듈이 법선을 이루도록 기존에 태양의 방위각 및 고도각을 제어하는 양축 추적시스템에 2개의 센서를 사용하였던 Double-sensor방식에서 1개의 센서로 방위각 및 고도각을 제어할 수 있는 One-sensor방식의 양축 추적시스템을 제안하였다. 그리고 제안한 추적시스템을 제작하여 시스템의 실제 운전을 실행하였다. 제안한 추적시스템은 1개의 센서를 이용하여 태양이 항상 법선을 이루면서 태양전지 모듈에 입사되게 제어하기 위해 방위각과 고도각을 제어하는 양축 추적시스템이다. 실험결과 가장 효율적인 운전과 불필요한 구동부의 동작을 방지하여 전력소모를 감소할 수 있었으며 고정식에 비해 본 논문에서 제안한 One-sensor방식의 양축 추적시스템이 약 23[%]의 발전효율이 증가함을 확인 할 수 있었다. 태양을 추적하여 더 많은 햇빛을 받게 하여 태양전지의 효율을 높이기 위하여 행해진 추적장치는 대형 방식에 많은 연구가 진행되어 왔다. 따라서 본 논문의 태양위치추적의 모니터링 시스템을 구축하여 지속적인 발전효율에 대한 실용화 연구를 통해 태양광발전시스템 보급에 큰 역할을 할 것이라 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.106.1-106.1
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• 2011

The Cu(In,Ga)Se2 (CIGS) thin film solar cells have been achieved until almost 20% efficiency by NREL. These solar cells include chemically deposited CdS as buffer layer between CIGS absorber layer and ZnO window layer. Although CIGS solar cells with CdS buffer layer show excellent performance, the short wavelength response of CIGS solar cell is limited by narrow CdS band gap of about 2.42 eV. Taking into consideration the environmental aspect, the toxic Cd element should be replaced by a different material. Among Cd-free candidate materials, the CIGS thin film solar cells with ZnS buffer layer seem to be promising with 17.2%(module by showa shell K.K.), 18.6%(small area by NREL). However, ZnS/CIGS solar cells still show lower performance than CdS/CIGS solar cells. There are several reported reasons to reduce the efficiency of ZnS/CIGS solar cells. Nakada reported ZnS thin film had many defects such as stacking faults, pin-holes, so that crytallinity of ZnS thin film is poor, compared to CdS thin film. Additionally, it was known that the hetero-interface between ZnS and CIGS layer made unfavorable band alignment. The unfavorable band alignment hinders electron transport at the heteo-interface. In this study, we focused on growing defect-free ZnS thin film and for favorable band alignment of ZnS/CIGS, bandgap of ZnS and CIGS, valece band structure of ZnS/CIGS were modified. Finally, we verified the photovoltaic properties of ZnS/CIGS solar cells.

• 한국재료학회지
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• 제29권11호
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• pp.720-726
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• 2019

Recently, research on cost reduction and efficiency improvement of crystalline silicon(c-Si) photovoltaic(PV) module has been conducted. In order to reduce costs, the thickness of solar cell wafers is becoming thinner. If the thickness of the wafer is reduced, cracking of wafer may occur in high temperature processes during the c-Si PV module manufacturing process. To solve this problem, a low temperature process has been proposed. Conductive paste(CP) is used for low temperature processing; it contains Sn57.6Bi0.4Ag component and can be electrically combined with solar cells and ribbons at a melting point of $150^{\circ}C$. Use of CP in the PV module manufacturing process can minimize cracks of solar cells. When CP is applied to solar cells, the output varies with the amount of CP, and so the optimum amount of CP must be found. In this paper, in order to find the optimal CP application amount, we manufactured several c-Si PV modules with different CP amounts. The amount control of CP is fixed at air pressure (500 kPa) and nozzle diameter 22G(outer diameter 0.72Ø, inner 0.42Ø) of dispenser; only speed is controlled. The c-Si PV module output is measured to analyze the difference according to the amount of CP and analyzed by optical microscope and Alpha-step. As the result, the optimum amount of CP is 0.452 ~ 0.544 g on solar cells.

• 전기학회논문지P
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• 제58권4호
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• pp.602-608
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• 2009

In this thesis, output voltage, current and power of solar module were classified by irradiation from data of overall operating characteristics collected for one year in order to manage efficient photovoltaic generation system and deliver maximum power. In addition, from these data, correlations between irradiation of photovoltaic cell and amount of power given by photovoltaic cell was quantitatively examined to deduce optimization of the design and construction of photovoltaic generation system. As I-V characteristics according to a temperature range of 10~50[$^{\circ}C$], the area of I-V characteristics were increased with an increase in temperature. Since this area corresponds to the power, output power is thought to have increased with temperature. As output power characteristics according to a temperature range of 10~50[$^{\circ}C$], output power was increased with an increase in temperature. Since output power increases with temperature increase, the result corresponds well to the related equation on temperature and output power. As I-V characteristics according to a irradiation range of 100~900 [$W/m^2$], voltage and current were increased with an increase in irradiation. The result is thought of as an increase in output power with increasing irradiation. As output power characteristics according to a irradiation range of 100~900 [$W/m^2$], output power was increased with increasing irradiation. This result corresponds well to the related equation on irradiation and output power.

• 조명전기설비학회논문지
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• 제28권2호
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• pp.31-41
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• 2014

This paper proposes the configuration of photovoltaic(PV) module considering the environment conditions of the PV system. The PV system is consisted of the series-parallel connection of the PV module. When shadows or changes of the radiation or an electrical characteristic in the solar cell are happened to PV system, the serious power loss will occur. If the PV module connected in series has the shadows, the output current is restricted to current of shaded PV module. Also if shadow is occurred to the parallel connection PV module, the output voltage is limited to voltage of shaded PV module. These problems are caused power loss. Therefore, this paper proposes the method that makes the output power of the PV module equalize by reconfiguration of PV module using the switching considering these environment conditions. A validity of the method proposed in this paper proves through comparing with performance of conventional PV module.