• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.226-226
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• 2003

The Commercial LiCoO$_2$ particles, which were 7.7${\mu}{\textrm}{m}$ in average diameter, were coated with $Al_2$O$_3$ by a gas suspension spray coating method. The coating amount of $Al_2$O$_3$ on the surface of LiCoO$_2$ was varied from 0.1 to 2 wt.% and compared their electrochemical characteristics with those of bare LiCoO$_2$. $Al_2$O$_3$ coating on the surface of LiCoO$_2$ increased surface area and electrical conductivity, and showed the better cycle and thermal stability even at the higher voltage. The observed optimum A1$_2$O$_3$ coating amount that exhibited the highest capacity retention was 0.2 wt.%.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.161-162
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• 2017

배터리 팩에 사용되는 리튬이온 배터리는 셀의 양극활물질에 따라 특성이 다르다. 배터리 팩의 효율적 운용을 위해 단위 셀간 편차를 최소화 하는 것이 필요하다. 본 논문에서는 양극활물질이 다른 고출력 및 고용량 리튬이온 배터리 세 종류를 선정하여 IR 및 OCV를 측정하고, 통계적 분석 기반 셀 스크리닝을 진행하여 결과를 비교 분석하였다.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.167-168
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• 2017

This paper investigates to identify an optimal for analysis of battery behavior in system-level applications such as Battery Energy Storage Systems in Smart Grid infrastructures and Electrical vehicles. At system level applications, it is mandatory to check model for meaningful equivalency and practical ability for extension from unit cell to Battery stack. The investigation of current battery models in relation to their suitability for study and analysis of system level applications of battery helpful for identification of optimal model and it also provides an intuition and direction to develop the most suitable model, if such models are not available already.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.159-160
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• 2017

본 논문에서는 리튬배터리의 전기화학적 분석법으로 전기 화학적 전압 분광법(electrochemical voltage spectroscopy;EVS)을 사용하였다. 전기화학적 활성상태의 밀도를 직접 측정하는 기법으로 정전압(potentiostatic) 제어를 기반으로 한다. EVS 테스트에서 양전극의 전압은 각 단계가 전기화학적 평행상태에 도달할 때 까지 유지되며 이 방법은 배터리의 전기화학적 산화 환원 전위의 미세한 차이에 기초하여 활성 물질의 상태에 대한 정확한 정보를 얻을 수 있다.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.487-494
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• 1995

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. We investigated the effects of lithium salts, plasticizer addition, temperature dependence of conductivity and electrochemical stability window of polyethylene oxide(PEO) electrolytes. PEO electrolyte completed with LiCIO$\_$4/ shows the better conductivity than the others. PEO-LiCIO$\_$4/ electrolyte, when EO/Li$\^$+/ ratio is 8, showed adequate conductivity around room temperature. By adding propylene carbonate and ethylene carbonate to PEO-LiCIO$\_$4/ electrolyte, its conductivity was higher than that of PEO-LiCIO$\_$4/ without those. Also PEO$\_$8/LiCIO$\_$4/ electrolyte remains stable up to 4.5V vs. Li/Li.

• Transactions of Materials Processing
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• v.13 no.4
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• pp.307-318
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• 2004

Rectangular drawn case with extreme aspect ratio is widely used for electrical parts such as a lithium-ion battery container, semi-conductor case and so on. Additionally, from the recent trend towards miniaturization of the multi-functional mobile device, demands for rectangular case with the narrow width are increased. In this study, numerical and experimental approaches for the multi-stage deep drawing process have been carried out. Based on the research results of the width of 5.95mm model, finite element analysis for storage case of rectangular cup type was verified to the width of 4.95mm. Also, a series of manufacturing experiments for rectangular case is conducted and the deformed configuration of the rectangular drawn case are investigated by comparing with the results of the numerical analysis. And the modification of the initial blank is performed to minimize the trimmed material amount. By the application of the modified blank, the sound shape of the deformed parts is improved.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.169-172
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• 2007

HEV용 리튬이온 전지에 대한 연구는 최근에 많은 연구가 진행되고 있으며 그중 고용량 및 저렴한 가격, 환경에 대한 안정성으로 인해 Li-Mn spinel에 대한 성능향상 연구가 많이 이루어지고 있다. 본 연구에서는 Li-Mn spinel의 입자크기에 대한 기초 물성 과 전기적 특성을 측정하여 입자크기가 용량에 미치는 영향에 대한 고찰을 하였다. Li-Mn spinel의 비표면적, C-V 특성, 전기적 용량, coulomb efficiency 등을 통하여 입자의 크기와 전해액, Li의 구동등과 관련하여 용량특성에 향상을 가져오는 입자크기 조건을 정의하였고 그에 따라 온도별로 합성 한 후 입자사이즈에 대한 특성을 나타내었다.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.157-157
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• 1999

Electrochromic tungsten oxide films were prepared by the electron beam deposition, and the dependence of the electrochemical stability and the optical properties on the titanium concentration, and on the annealing temperature, that was investigated. coloring and bleaching experiments were repeated by cyclic voltammetry in a propylene carbonate solution of LiClO4. Spectrometry was used to assess the stability of the transmittance in the degraded films. Tungsten oxide films with titanium contents of about 10~15 mol% were found to be most stable, undergoing the least degradation during the repeated for coloring and bleaching cycles. The reason for this small amount of degradation was the reduction of lithium ion trapping sites in the films, which results in an increased durability. Tungsten oxide films with titanium contents of about 20 mol% were annealed at 20$0^{\circ}C$ for 1 hour, and this results showed that durability of films were increased.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1042-1043
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• 2015

미니트램(Mini-Tram)은 승하차 시간 동안 정거장에서의 무선급전 방식에 의한 급속충전(약, 2분 30초 이내)을 통해 에너지를 공급받으며, 운행 시 차상에 설치된 에너지저장 매체(LIC: Lithium-Ion Capacitor)로부터 전기에너지를 공급받아서 운행된다. 차량에 요구되는 에너지 소모량을 분석하고 이에 맞춰서 저장 매체의 직-병렬 구성 및 전력 변환 장치(Regulator 및 DC-DC 컨버터 등)를 설계하는 것은 전기 구동 차량인 미니트램의 설계에서 매우 중요한 부분이다. 본 논문에서는 미니트램 시스템을 개발하는 과정에서 수행된 에너지공급시스템의 사양 선정을 위한 에너지 소모량 예측과 더불어 이와 관련된 주행저항 및 주행성능 분석에 대해서 다룬다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.365.1-365.1
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• 2014

Cobalt oxide has excellent various properties such as high catalytic activity, antiferromagnetism, and electrochromism. So cobalt oxides offer a great potential for their applications in the various areas such as optical gas sensor, catalysts for oxidation reaction, electrochromic devices, high temperature solar selective absorbers, magnetic materials, pigment for glasses and ceramics, and negative electrodes for lithium-ion batteries. We have synthesized novel cobalt complexes by simple reaction of cobalt bistrimethylsilylamide as a starting material with a lot of conventional ligands as potential cobalt oxide precursors. The studies include the facile preparation, structural characterization, and spectroscopic analysis of the new precursors. We are making efforts to grow cobalt oxide thin films using cobalt complexes newly synthesized in this study using deposition techniques.