• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.68-68
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• 2010

To reduce PV manufacturing costs, the thickness of solar cell is getting thinner. Bow is shown after cooling down the temperature of solder cell. It happens because of different thermal expansion coefficients of different metals. Bowed cell can make micro crack while module processing and it can drop off efficiency of PV module. As thinner solar cell is produced, the thickness of ribbon should be concerned to prevent extra bow. In this paper we investigate the contrast of deflection when we solder different thickness of ribbons on same solar cell. This approach would help to find out the optical thickness of ribbon for particular thickness of solar cell later on.

• 대한안전경영과학회지
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• 제17권4호
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• pp.397-401
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• 2015

In this study, analysed the characteristics of power drop and surface damage in solar cell through high temperature and humidity test in the 3 case of EVA(ethylene vinyl acetate) and 2 case ribbon thickness. The solar cells were tested during the 500hr in $85^{\circ}C$ temperature and 85% relative humidity conditions, that excerpted standard of PV Module(KS C IEC-61215). Through the EL(Electroluminescence) shots, specimen's surface have partialy damaged. Before and after high humidity and high temperature test, ribbon thickness $200{\mu}m$ EVA1 case power drop rate was 8.463%, EVA2 case was 6.667%, EVA3 case was 6.373%. In the ribbon thickness $250{\mu}m$ EVA1 case power drop rate was 6.521%, EVA2 case was 8.517%, EVA3 case was 6.019%. EVA3 case was the lowest power and FF(fill factor) drop rate at the 2 case of ribbon thickness, because EVA3 is laerger than EVA1 and EVA2 in thickness, elongation and tensile strength.

• 한국자기학회지
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• 제8권5호
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• pp.255-260
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• 1998

두께 10$\mu\textrm{m}$ 이하의 코발트계 극박형 비정질합금의 진공중 용탕급냉방법에 의한 제조조건과 자기적 특성에 대해 연구되었다. 구리 냉각롤의 회전 선속도를 55 m/s로 하였을 때, 0.05 kgf/cm2 이하의 용탕분사압 조건에서 극박형 리본이 얻어졌다. 합금 두께는 용탕분사 가스압력의 감소에 비례하여 직선적으로 감소하였으며, 이와 동시에 폭의 감소도 함께 일어났다. 이는 극박형 합금을 만들기 위해 용탕분사압을 극단적으로 감소시키면 노즐구의 양단부에서 용융금속과 노즐 사이의 마찰효과가 크게 나타나 유효분사압이 현저히 감소하는 데에 기인하는 것으로 해석되었다. 저주파(1 kHz) 실효투자율은 대략 2차 함수의 관계로 리본 두께의 감소에 따라 저하되었다. 반면 보자력은 두께의 감소에 반비례하여 증가하였는데, 이들 현상은 거의 전적으로 표면효과의 증대에 의한 자벽이동의 억제에 그 원인이 있는 것으로 판단되었다. 그러나 고주파(1 MHz) 실효투자율은 두께의 감소에 따라 증가하였는바 이는 와전류 발생이 억제되어 자기장 방향으로의 자화회전이 보다 용이해지기 때문으로 생각되었으며, 결과적으로 극박화에 의해 MHz 대역에서 우수한 저손실 성질을 나타내는 자심 특성의 실현이 가능하였다.

• 한국자기학회지
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• 제5권5호
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• pp.500-503
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• 1995

The magnetic properties of ultrathin $Fe_{84}B_{9}Nb_{7}$ nanocrystalline ribbon alloy with the thickness of $7-14\;\mu\textrm{m}$ were investigated. It was found that the effective permeability at the frequency over 100 kHz increased with decreasing ribbon thickness. Moreover the core loss decreased considerably with reduction of the ribbon thickness. The effective permeability at 1 MHz and the core loss at 1 MHz and 0.1 T for $Fe_{84}B_{9}Nb_{7}$ alloy with the thickness of $7\;\mu\textrm{m}$ were 3,700 and 2.7 W/cc, respectively. The reduction of thickness to less than $10\;\mu\textrm{m}$ was found to be very effective in obtaining high permeability and low core loss in the MHz frequency range. It was considered that the improvement of magnetic properties in the high frequency range was due to the reduction of the eddy current.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1525-1526
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• 2013

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.73-76
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• 1999

In this thesis, we fabricate a zero-magnetostrictive amorphous ribbon measure the impeadance effect, and then Investigate possibility as a sensor material. $Co_{72.5}$F $e_{0.5}$M $o_{2}$ $B_{15}$ S $i_{5}$ is used as composition of specimen alloy. We first melt the specimen in high frequency induction furnace and then rapidly quench it by using single roll technique. As the result, we obtain a ribbon where thickness is 12${\mu}{\textrm}{m}$, width is 1mm and length is 93mm. Consequently, it is proved through this study that zero-magnetostrictive amorphous ribbon can be used as an excellent magnetic sensor material.rial.l.

• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.217-220
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• 2014

We studied the plating properties of Sn-Pb solder according to the shape of the Cu wire's cross-section for photovoltaic ribbon. The thickness of the Sn-Pb layer largely decreased to 29% on a curved Cu surface, compared to a flat Cu surface. This phenomenon is caused by the geometrical decrease in the contact angle of the liquid Sn-Pb solder and an increase in the surface energy of the solid/vapor on the curved Cu surface. We suggest a new ribbon's design where the Cu wire's cross-section is a semi-ellipse. These semi-ellipse ribbons can decrease the use of Sn-Pb solder to 64% and increase the photovoltaic efficiency, by reducing the contact area between the ribbon and cell, to 84%. We also see an improvement of reflectivity in the curved surface.

• 열처리공학회지
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• 제30권6호
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• pp.251-257
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• 2017

The effect of annealing temperature on the martensitic transformation behavior, tensile deformation chracteristics and shape recovery etc., has been studied in TiNi based shape memory ribbon fabricated by coldrolling of wire. TiNi based shape memory wire (${\phi}=500{\mu}m$) of which structure is intermetallic compound could be cold-rolled without process annealing up to the reduction rate in thickness of 50%, but a few cracks appear in cold-rolled ribbon in the reduction rate in thickness of 65%. The $B2{\rightarrow}R{\rightarrow}B19^{\prime}$ martensitic transformation or $B2{\rightarrow}B19^{\prime}$ martensitic transformation occurs in annealing conditions dissipating lattice defects introduced by coldrolling. However, in case of higher reduction rate or lower annealing temperature, martensitic transformation in cold-rolled and then annealed ribbons does not occur. The maximum shape recovery rate of cold-rolled ribbons with the reduction rate of 35 and 65% could be achieved at annealing temperatures of 250 and $350^{\circ}C$, respectively. The shape recovery rate seems to be related to the stress level of plateau region on stress-strain curve.

• 한국주조공학회지
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• 제17권3호
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• pp.276-285
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• 1997

The effect of wheel surface condition on solidification behavior of Al-Cu ribbon was investigated in order to establish extreme levels of heat extraction. The condition of wheel surface was changed either by heating the wheel surface up to $200^{\circ}C$ or by coating boron nitride(BN) onto the the rim of a wheel. Heating the wheel surface up to $200^{\circ}C$ improved the wetting behavior between the molten metal and the rotating wheel, leading to an increase in the ratio of columnar structure to the entire thickness of Al-4.3wt%Cu and Al-33.2wt%Cu ribbons. For Al-4.3wt%Cu ribbon, assuming one grain as a single heterogeneous nucleation event at the contact point, the nucleation density with the wheel surface heated to $200^{\circ}C$, was $4{\times}10^6/mm^2$, and in the cases of BN coating with thin and thick layers, $10^5/mm^2$ and $5{\times}10^4/mm^2$, respectively. The largest cooling capacity of the wheel corresponded to the heated wheel surface, and as the thickness of BN coating layer increased, the cooling capacity of the wheel gradually decreased.

• 에너지공학
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• 제22권4호
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• pp.333-337
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• 2013

본 논문에서는 태양전지의 Ribbon 두께(A-type:0.2mm, B-type:0.25mm)에 따라 3가지 온도조건 ($-40{\sim}65^{\circ}C$, $-40{\sim}85^{\circ}C$, $-40{\sim}105^{\circ}C$)으로 열충격 시험을 수행하였다. 그 결과, A, B type 별 초기 평균효율은 15.2%로 같았다. 하지만, 열충격 시험(600 Cycle) 후 Condition 1에서 A-type 7.5%, B-type 7.7%, Condition 2에서는 8.6%, 13.2%를 나타내었다. Condition 3에서는 각각 11.6%, 19.9%의 감소율을 나타내었다. 열충격 시험 후 A-type보다 Ribbon두께가 두꺼운 B-type의 효율이 크게 감소하였다. 이는 A, B type 모두 이종재료 접합부의 금속간화합물(IMC)층이 형성되어 전기적 저항이 증대된 것으로 판단된다. 또한, B-type의 I-V 특성 곡선 및 EL을 분석한 결과, p-n층이 파괴되고, 병렬저항이 감소하여, 장기적 신뢰성에서 A-type 보다 더 취약한 것으로 나타났다. 향후 태양전지 Ribbon 형상에 따른 장기 신뢰성 특성에 대해 수치해석 및 시뮬레이션 분석이 수반되어야 할 것이다.