• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.100-106
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• 2009

A novel 8 V DC power source with an external series-parallel connection of 50 Dye-sensitized Solar Cells (DSCs) has been proposed. One DSC has the optimized length to width ratio of $5.2{\times}2.6\;cm$ and an active area $8\;cm^2$ ($4.62{\times}1.73\;cm$) which attained a conversion efficiency of 4.02%. From the electrochemical impedance spectroscopic analysis, it was found that the resistance elements related to the Pt electrode and electrolyte interface behave like that of diode and the series resistance corresponds to the sum of the other resistance elements. Surface morphology and sheet resistance of Pt counter electrode did not degrade the performance of the cell. This novel 8V-0.33A DC power source shows stable performance with an energy conversion efficiency of 4.24% under 1 sun illumination (AM 1.5, Pin of $100\;mW/cm^2$).

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1100-1101
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• 2008

After lamination process, Isc is increased by sheet reflection. This paper presents the electrical output characteristics by back sheet reflection. The experiments was conducted by using single crystalline and multi crystalline PV module. The reflection area of single crystalline PV module is larger than multi one due to the difference of solar cell manufacturing. The experiments show that the increased performance ratio of single crystalline PV module output power is 1.55% rather than that of multi crystalline PV module output power is 1.13%. In addition, it is expected that the output power of single one rather than multi-one is increased by the lower temperature when the PV module is installed outside. The results can be reconsidered by the test material and test process. Back sheet used for humidity prevention makes PV module output power increasing.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.63.1-63.1
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• 2011

To analyze the phenomenon of corrosion in the PV module, we experimented damp heat test at $85^{\circ}C$/85% relative humidity(RH) and $65^{\circ}C$/85% RH for 2,000 hours, respectively. We used 30 mini-modules designed of 6inch one cell. Despite of 2,000 hours test, measured $P_{max}$ is not reached failure which is defined less than 80% compared to initial $P_{max}$. Therefore, we calculate proper curve fitting over 2,000 hours. Data less than 80% $P_{max}$ is found and B10 lifetime is calculated by the number of failure specimens and weibull distribution. Using B10 lifetime that the point of failure rate 10% and Peck's model, the predictable equation of lifetime was derived under temperature and humidity condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.341-341
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• 2011

초발수 표면은 자가세정, 부식방지, 방오특성의 특징을 가진다. 이러한 특성은 오염성이 높은 건물외장재 및 자동차유리, 태양전지 모듈유리, 디스플레이등 적용분야가 매우 다양하며, 코팅 방법으로 sol-gel, CVD, PVD등의 여러 가지 방법으로 많은 연구가 보고 되고 있다. 초발수 표면을 제작하는 대표적인 방법으로 PTFE와 같은 낮은 표면에너지를 가지는 물질을 증착하는 방법이 많이 사용되고 있으나, 초발수 표면에 가까운 접촉각을 구현하기에는 한계가 있다. 본 연구에서는 여러 가지 기판(Al, Cu, Sus, glass)에 추가적으로 표면 미세요철구조를 만들어 특성을 분석 하였다. 표면의 미세구조는 기판을 산에 Etching 하는 방법으로 Sample을 준비 하였다. 준비된 기판에 RF-Magnetron Sputtering 방법을 이용하여 PTFE를 증착하여 특성을 분석 하였다. 표면과 물방울이 이루는 각도를 알아보기 위해 Contact Angle을 측정한 결과 Glass와 Sus 기판을 제외한 Al과 Cu기판에서 약 150도에 이르는 초발수 특성을 보였으며, 이러한 표면형상을 관찰하기 위해서 SEM 측정을 해본 결과 표면의 미세요철구조가 확인 되었으며, AFM 측정결과 표면의 미세요철의 거칠기가 Etching공정을 통해 증가 된 것을 확인할 수 있었으며, Etching후 Al과 Cu는 수 nm ~ mm의 거칠기를 보였으며, 거칠기가 증가하여 접촉각의 향상에 기여 하였으리라 생각된다. XPS 측정결과 낮은 표면에너지를 가지는 CF2와 CF3 피크가 보이는 것으로 보아 표면에너지가 낮아져 접촉각이 높아졌으리라 사료 된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.13-14
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• 2008

In this paper, we analyze the electrical characteristics of PV depending on distance among solar cells before and after lamination process. From the result, the PV module's maximum power increases about 3.37% when solar cells's distance is 10mm. And the maximum power increases up to 8.42% when solar cells's maximum distance is 50mm. It is assumed that PV module's surface temperature decreases because of increasing distance between solar cells that would give high power generation. Also, short distance between solar cell and frame result in contamination on glass. When considering reduced maximum power caused by contaminant, from that, we can fabricated PV module of lower cost with high performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.9-9
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• 2008

Recently, the thickness of solar cell gets thinner to reduce the quantity of silicon. And the reduced thickness make it easy to be broken while PV module fabrication process. This phenomenon might make PV module's maximum power and durability down. So, when using thin solar cell for PV module fabrication, it is needed to optimize the material and fabrication condition which is quite different from normal thick solar cell process. Normally, gel-content of EVA sheet should be higher than 80% so PV module has long term durability. But high gel-content characteristic might cause micro-crack on solar cell. In this experiment, we fabricated several specimen by varying curing temperature and time condition. And from the gel-content measurement, we figure the best fabrication condition. Also we examine the crack generation phenomenon during experiment.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.72-75
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• 2001

The solar energy is purity and infinity. Solar power converter were used to convert the electrical energy from the solar arrays to a stable and reliable power source. So much country research this solar energy system. The photovoltaic system is construct many solar cell array, In this paper, new implementation solar system was showed buck converter that V-I curve produced. This system can be used to study the short-term and long-term performances of solar cell and efficiency. This system is a far more cost effective and reliable replacement for field and outdoor flight testing. Study of buck converter, analysis and control shun t$\cdot$series connection characteristics of solar cell array.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.291-296
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• 2020

The high power of a shingled photovoltaic module can be attributed to its low cell-to-module loss. The production of high power modules in limited area requires high efficiency solar cells. Shingled photovoltaic modules can be made by divided solar cells, which can be produced by the laser scribing process. After dividing the 21% PERC cell using laser scribing, the efficiency decreased by approximately 0.35%. However, there was no change in the efficiency of the solar cell having relatively lower efficiency, because the laser scribing process induce higher heat damages in solar cells with high efficiency. To prove this phenomena, the J₀ (leakage current density) of each cell was analyzed. It was found that the J₀ of 21% PERC increased about 17 times between full and divided solar cell. However, the J₀ of 20.2% PERC increased only about 2.5 times between full and divided solar cell.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.26-28
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• 2005

In this paper, degradation in field-aged PV modules including degradation of interconnect, discoloration of encapsulant and hot spot have been observed and analyzed. From the results, photovoltaic module installed for 15 years shows around 13~20% drop of electrical properties due to the interconnect degradation and PV module passed 19 years has been found to drop of around 20% mainly by the encapsulant discoloration. Fill factor of the electrode oxidized photovoltaic module has been dropped by the amount of 6~10% due to the change of irradiance. It is because maximum voltage(Vmp) decreases according to the increase of irradiance.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1775-1777
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• 2005

In this paper, maximum output of three different temperature conditions of the photovoltaic modules have been tested and compared to obtain the optimum conditions for the maximum power operation. Temperatures of the cell and module have been set to $20^{\circ}C$, $25^{\circ}C$ and $30^{circ}C$ under the constant light intensity of 1kW/$m^2$. 125${\times}$125mm 36 single crystal solar cells having 80 [W] each have been serially connected in the module. From the results, maximum output deviation of 4.67% has been obtained under the ceil temperature of $20^{\circ}C$ and module temperature of $30^{\circ}C$ while minimum deviation of 0.41${\sim}$0.92% has been measured under the same temperatures of cell and module. Therefore it has been found that the temperature of both cell and module should be fixed to $25^{\circ}C$ to obtain stable data unless the temperature coefficient should be compensated for the testing sample.