• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.198-204
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• 2013

Acoustic emission(AE) signal was detected during charge and discharge of lithium ion battery to investigate relationships among cumulative count, discharge capacity, and microdamages. AE signal was received during accelerated charge/discharge cycle test of a coin-type commercial battery. A number of AE signals were successfully detected during charge and discharge, respectively. With increasing number of cycle, discharge capacity was decreased and AE cumulative count was observed to increase. Microstructural observation of the decomposed battery after cycle test revealed mechanical damages such as interface delamination and microcracking of the electrodes. These damages were attributed to sources of the detected AE signals. Based on a linear correlation between discharge capacity and cumulative count, feasibility of AE technique for evaluation of battery degradation was suggested.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.147-148
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• 2014

1990년에 Sony사는 탄소 음극과 리튬 코발트 산화물($LiCoO_2$) 양극을 함유하는 최초의 상용 리튬이온 전지를 발표하였다. 이후, 전지 성분을 변형하여 안전성과 전기화학적 용량을 향상시키고 비용을 줄이기 위한 연구가 수행되었다. 이러한 관심의 대부분은 양극 용량이 전지 용량을 한정하고 전지 비용의 40%까지 양극 원재료 비용에서부터 비롯되었기 때문에 양극 대체기술 개발에 집중되었다. 리튬이온 전지는 현재 휴대용 전자 기기 시장을 좌우하고 있다. 또한 온실가스 배출의 감소를 요구하는 환경보호에 대한 관심에 대한 새로운 시장 기회가 조성되었다. 1990년대 이후, 비독성의 저가 재료를 사용하여 환경 영향과 비용을 최소화 하려는 노력을 경주하면서 에너지 밀도를 극대화하고, 리튬 삽입과 추출의 유용 범위를 확대하여 용량을 극대화하고 있다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.113-114
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• 2015

본 논문은, 태양광 및 차세대 이동수단에 적용되는 리튬-이온 전지의 전기적 모델링를 수행하였다. 전지의 전기적 모델링을 통하여 충 방전 특성, 용량, 개방 전압, 내부 저항과 같은 전지의 특성을 모의함으로써, 다양한 환경에서 어플리케이션에 적용할 전지를 테스트해 볼 수 있다. 리튬-이온 전지는 LGD 18650 B4(2,600mAh) 모델을 사용하였으며, 실험과 시뮬레이션을 통하여 설계된 모델의 타당성을 검증한다.

• Membrane Journal
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• v.30 no.4
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• pp.228-241
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• 2020

Separators, which produces physical layer between a cathode and anode, are getting enormous attention as the quality of the separator determines the performance of lithium ion batteries (LIBs). Porous membranes based on polyethylene (PE) and polypropylene (PP) are generally utilized as the separator of LIBs because of their high electrochemical stability and suitable mechanical strength. However, low thermal resistance and wettability of PE and PP membranes limited the potential of LIBs. Operating at the temperature exceeding the melting point of membranes, the separators change their structures which lead to short circuit of LIBs. Low wettability of the separators corresponds to low ionic conductivity which increases the cell resistance. To overcome these weaknesses of PE and PP separators, different types of separator were prepared by co-electrospinning, applying coating layer, forming core shell around membrane, and papermaking method. The synthesized separator greatly enhanced the heat resistance and wettability of separator and mechanical properties like flexibility and tensile strength. In this review different type of polymer membrane used as separator in lithium ion battery are discussed.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.371-375
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• 2011

전지는 고에너지 밀도 제품으로 화학에너지를 전환시켜 전기에너지를 운반하는 것이다. 본 실험에서는 리튬 이온전지의 열적 안정성의 위험을 평가하기 위하여 리튬이온 전해액을 Differential Scanning Calorimeter(DSC)와 modified cloed pressure vessel test(MCPVT)로 분석하였다. 실험 결과 리튬전지는 다른 전지보다 위험하며, 전지를 잘못 사용하면 열적 반응성은 연소성 물질인 전해질을 포함하고 이것이 열을 발생시켜 폭발하거나 화재가 발생할 수 있음을 제시하였다.

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.31-35
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• 2007

In this review article, we are going to explain the recent development of lithium secondary batteries for a cellular phone. There are three kinds of rechargeable batteries for cellular phones such as nickel-cadmium, nickel-metal hydride, and lithium ion or lithium ion polymer. The lithium secondary battery is one of the most excellent battery in the point of view of energy density. It means very small and light one among same capacity batteries is the lithium secondary battery. The market volume of lithium secondary batteries increases steeply about 15% annually. The trend of R&D is focused on novel cathode materials including $LiFePO_4$, novel anode materials such as lithium titanate, silicon, and tin, elecrolytes, and safety insurance.

• Composites Research
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• v.35 no.6
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• pp.365-370
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• 2022

According to the rapid growth of electric vehicle (EVs) and E-mobility market, Li-ion batteries are one of the most progressive technologies. The demand of LIBs with high energy capacity, rate performance and fast charging is continuously increasing, hence high-performance LIBs should be developed. Si is considered as the most promising anode material to improve energy density because of its high theoretical capacity. However, Si suffers large volume chances during the charging and discharge process, leading to the fast degradation of cycle performance. Therefore, polymeric binders play a key role in electrochemical performance of Si anode by efficiently enduring the Si expansion and maintaining the binding networks in electrode. In this review, we explain the role of polymeric binders in electrode and introduce the anode binders with enhanced mechanical and chemical properties which can improve electrochemical performances of Si-based anode.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.109-122
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• 2011

The production capacity of EV models should be sufficient to achieve the goal of one million EVs by 2015. Large-Format lithium-ion battery are expected to find a prominent role as ideal electrochemical storage systems in traction power train for sustainable vehicles such as all-electric vehicles. This review focuses first on the present status of production lithium-ion battery technology and cooperative relations of between battery and EV makers, then on its near future development.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.81-91
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• 2010

Plug-in hybrid electric vehicles(PHEVs) are gaining attention over the world due to their abilities to reduce $CO_2$ emission and gasoline/diesel consumption by using electricity from the grid. Lithium ion battery is one of the most suitable candidates as energy storage device for PHEVs applications up to 2030. This review focuses on the present status of lithium ion battery technology, then on comparison of the performance characteristics of the promising cathode materials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.1
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• pp.47-53
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• 2016

The electrolyte wetting phenomena occurring in the electrode of lithium-ion battery was studied using lattice Boltzmann method (LBM). Recently, lithium-ion batteries are being mixed with small particles on the active material to increase the capacity and energy density during the electrode design stage. The change to the mixing ratio may influence the wettability of electrolyte. In this study, the changes in electrolyte distribution and saturation were investigated according to various mixing ratios of active material. We found that the variations in mixing ratio of active material affect the wetting mechanism, and result in changes to the wetting speed and wettability of electrolyte.