• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.607-608
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• 2015

본 논문에서는 산업용 및 건물용 수용가에 에너지저장장치(이하 'ESS')를 설치하여 운영 사례 결과를 나타냈다. 산업용 수용가는 리튬(Lithium) 기반 1MW/500kWh를, 건물용 수용가는 나트륨-니켈(NaNi) 기반 500kW/1MWh를 각각 설치하여 전기요금별, 배터리 특성별, 운전 조건별로 운영 사례를 나타냈다.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.78-79
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• 2013

본 논문에서는 태양광 및 리튬 이온 배터리를 에너지원으로 하는 계통 연계 시스템을 효과적으로 구성하기 위해 스위치 손실을 그 기준으로 삼았다. 따라서, 두 가지 종류의 회로구성에 대해 손실 예측 비교를 사용하였다. 전력 반도체의 스위칭 손실 및 도통시 전류, 전압 관계를 모델링 하였고 시물레이션을 이용해 손실 예측을 하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.392-393
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• 2019

본 논문에서는 전기 보트 추진을 위한 SPMSM(Surface mounted Permanent Magnet Synchronous Motor) 구동 시스템을 개발하였다. 전차원 폐루프 관측기를 이용하여 외란 토크 관측기를 구성하고, 관측된 외란 성분을 속도 제어기 출력에 보상하여 속도 제어 성능을 향상시켰다. 리튬이온 배터리, 인버터 및 1kW SPMSM으로 구성된 전기 보트 추진 시스템을 이용한 구동 실험을 통해 추진용 전동기의 속도 제어 특성을 확인하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.453-454
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• 2019

본 논문은 ESS(Energy Storage System)의 과충전, 과방전으로 인한 열 폭주 현상을 방지하기 위한 사전 연구로 원통형 리튬이온 단일 셀의 충/방전에 따른 열 분포를 열화상 카메라로 촬영하여 분석하였다. 실험을 통한 열 분포 이미지를 학습 데이터로 구성하여, SOC(State of Charge)를 추정하는 CNN(Convolution Neural Network) 모델을 제안한다.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.383-391
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• 2020

Purpose: To identify internal self ignition and ignition caused by external flames in energy storage rooms, and to analyze the difference between ignition due to overheating and ignition caused by external heat sources. Method: membrane melting point measurement, battery external hydrothermal experiment, battery overcharge experiment, comparative analysis of electrode plate during combustion by overcharge and external heat, overcharge combustion characteristics, external hydrothermal fire combustion characteristics, 3.4 (electrode plate comparison) / 3.5 (overcharge) /3.6 (external sequence) analysis experiment. Result: Since the temperature difference was very different depending on the position of the sensor until the fire occurred, it is judged that two temperature sensors per module are not enough to prevent the fire through temperature control in advance. Conclusion: The short circuit acts as an ignition source and ignites the mixed gas, causing a gas explosion. The electrode breaks finely due to the explosion pressure, and the powder-like lithium oxide is sparked like a firecracker by the flame reaction.

• Membrane Journal
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• v.34 no.1
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• pp.1-9
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• 2024

The rapid expansion of the electric vehicle market has led to increased demand for battery recycling technologies. The recycling of spent batteries is crucial to stabilize the supply of rare metals, including lithium, cobalt and nickel, which are essential components for the battery industry. In addition, the technology for recycling spent batteries can help to reduce environmental and health impacts. This review presents the theoretical principles behind the metal recovery technology and the processes that are currently commercially available. It also describes trends in research and technological developments that aim to improve existing processes, and provides an overview of where recycling technology is headed.

• Fire Science and Engineering
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• v.33 no.4
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• pp.59-69
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• 2019

The present article relates to an experimental study on fire risks due to overcharge and external heat of ESS lithium battery. According to the experimental results of overcharge, ignition occurred as combustible gas and smoke was slowly increased after occurrence of venting, and an explosive combustion form accompanied by flame eruption and sparks was displayed as charged energy is rapidly discharged in an instant. On the other hand, according to the experimental results of external heat, as a tremendous amount of combustible gas and smoke was ignited following being discharged after occurrence of vent, the charged energy itself was rapidly reduced due to the discharged energy so that a passive combustion form was observed when compared with overcharge after occurrence of flames. According the analysis results of fire damage characteristics, differences between external heat (External flame) could be found through visual and X-ray inspections. Namely, while inside electrode plate was completely destroyed and perforation of the electrode plate was observed in the case of overcharge, fire damage of the electrode plate was not severe maintaining the form in the case of external heat.

• Clean Technology
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• v.29 no.2
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• pp.87-94
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• 2023

The recovery of valuable metals from waste lithium-based secondary batteries is very important in terms of efficiently utilizing earth's limited number of resources. Currently, the cathode material of a LiFePO₄ battery, a type of battery which is widely used in automobiles, contains approximately 5% lithium. After use, the lithium in these batteries can be used again as a raw material for new batteries through lithium recycling. In this study, low-concentration sulfuric acid, a commonly used type of inorganic acid, was used to selectively leach the lithium contained in a waste LiFePO₄ cathode material powder. In addition, in order to compare and analyze the leaching efficiency and separation efficiency of each component, the optimalleaching conditions were derived by applying a two-step leaching process with pulp density being used as a variable during leaching. When leaching with pulp density as a variable, it was confirmed that at a pulp density of 200 g/L, the separation efficiency was approximately 200 times higher than at other pulp densities because the iron and phosphorus components were hardly leached at this pulp density. Accordingly, the pulp density of 200 g/L was used tooptimize the leaching conditions for the selective leaching and recovery of lithium.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.729-744
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• 2023

The value of lithium has significantly increased due to the rising demand for electric cars and batteries. Lithium is primarily found in pegmatites, hydrothermally altered tuffaceous clays, and continental brines. Globally, groundwater-fed salt lakes and oil field brines are attracting attention as major sources of lithium in continental brines, accounting for about 70% of global lithium production. Recently, deep groundwater, especially geothermal water, is also studied for a potential source of lithium. Lithium concentrations in deep groundwater can increase through substantial water-rock reaction and mixing with brines. For the exploration of lithim in deep groundwater, it is important to understand its origin and behavior. Therefore, based on a nationwide preliminary study on the hydrogeochemical characteristics and evolution of thermal groundwater in South Korea, this study aims to investigate the distribution of lithium in the deep groundwater environment and understand the geochemical factors that affect its concentration. A total of 555 thermal groundwater samples were classified into five hydrochemical types showing distinct hydrogeochemical evolution. To investigate the enrichment mechanism, samples (n = 56) with lithium concentrations exceeding the 90th percentile (0.94 mg/L) were studied in detail. Lithium concentrations varied depending upon the type, with Na(Ca)-Cl type being the highest, followed by Ca(Na)-SO₄ type and low-pH Ca(Na)-HCO₃ type. In the Ca(Na)-Cl type, lithium enrichment is due to reverse cation exchange due to seawater intrusion. The enrichment of dissolved lithium in the Ca(Na)-SO₄ type groundwater occurring in Cretaceous volcanic sedimentary basins is related to the occurrence of hydrothermally altered clay minerals and volcanic activities, while enriched lithium in the low-pH Ca(Na)-HCO₃ type groundwater is due to enhanced weathering of basement rocks by ascending deep CO₂. This reconnaissance geochemical study provides valuable insights into hydrogeochemical evolution and economic lithium exploration in deep geologic environments.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.50-60
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• 2007

There are several kinds of battery such as zinc-air battery, lithium battery, Manganese dry battery, silver oxide battery, mercury battery, sodium-sulphur battery, lead battery, nickel-hydrogen secondary battery, nickel-cadmium battery, lithium ion battery, alkaline battery, etc. These days it has been widely studied for the recycling technologies of the used battery from view points of economy and efficiency. In this paper, patents on the recycling technologies of the used lithium battery were analyzed. The range of search was limited in the open patents of USA(US), European Union(EP), Japan(JP), and Korea(KR) from 1986 to 2006. Patents were collected using key-words searching and filtered by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.