• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.477-477
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• 2009

Bimodal Tram developed by KRRI is driven by a series Hybrid propulsion system which has both the CNG engine, generator and LPB(Lithium Polymer Battery) pack. It has three driving modes; Hybrid mode, Engine mode and Battery mode. Even in case of Battery mode, LPB pack to get enough power to drive the vehicle only by itself onsists of 168 LPB cells(80Ah per lcell), 650V. It is important thing to manage LPB pack in a right way, which will extend the lifetime of LPB cells and operate in the hybrid mode effectively. This paper has shown the development of battery management system(12 BMS, 1 BMS per 14cells) to manage LPB pack which is connected with CAN(Controller Area Network) each other and measure the voltage, current, temperature and also control the cooling fan inside of LPB pack. Using the measured data, BMS can show the SOC(State of Charge), SOH(State of Health) and other status of LPB pack including of the cell balancing.

• 전기학회논문지P
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• 제64권4호
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• pp.231-235
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• 2015

Bimodal Tram developed by KRRI is driven by a series Hybrid propulsion system which has both the CNG engine, generator and LPB(Lithium Polymer Battery) pack. It has three driving modes; Hybrid mode, Engine mode and Battery mode. Even in case of Battery mode, LPB pack to get enough power to drive the vehicle only by itself onsists of 168 LPB cells(80Ah per lcell), 650V. It is important thing to manage LPB pack in a right way, which will extend the lifetime of LPB cells and operate in the hybrid mode effectively. This paper has shown the development of battery management system(12 BMS, 1 BMS per 14cells) to manage LPB pack which is connected with CAN(Controller Area Network) each other and measure the voltage, current, temperature and also control the cooling fan inside of LPB pack. Using the measured data, BMS can show the SOC(State of Charge), SOH(State of Health) and other status of LPB pack including of the cell balancing.

• 전기학회논문지
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• 제66권12호
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• pp.1889-1894
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• 2017

Global automobile manufacturers are developing electric vehicles (EVs) to eliminate the pollutant emissions from internal combustion vehicles and to minimize fossil fuel consumptions for the future generations. However, EVs have a disadvantage of shorter traveling distance than that of conventional vehicles. To answer this shortfall, more batteries are installed in the EV to satisfy the consumer expectation for the driving range. However, as the energy capacity of the battery mounted in the EV increases, the amount of heat generated by each cell also increases. Naturally, a better battery thermal management system (BTMS) is required to control the temperature of the cells efficiently because the appropriate thermal environment of the cells greatly affects the power output from the battery pack. Typically, the BTMS is divided into an active and a passive system depending on the energy usage of the thermal management system. Heat exchange materials usually include gas and liquid, semiconductor devices and phase change material (PCM). In this study, an application of PCM for a BTMS was investigated to maintain an optimal battery operating temperature range by utilizing characteristics of a PCM, which can accumulate large amounts of latent heat. The system was modeled using Dymola from Dassault Systems, a multi-physics simulation tool. In order to compare the relative performance, the BTMS with the PCM and without the PCM were modeled and the same battery charge/discharge scenarios were simulated. Number of analysis were conducted to compare the battery cooling performance between the model with the aluminum case and PCM and the model with the aluminum case only.

• 한국산학기술학회논문지
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• 제18권8호
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• pp.1-7
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• 2017

본 논문은 퍼스널 모빌리티에 사용되는 360 Wh급 리튬이온 배터리 팩의 성능 및 안정성 확보를 위하여 리튬이온 배터리 팩의 열전달 특성에 관하여 상용수치해석 프로그램인 ANSYS v17.0의 CFX를 이용하여 수치적으로 연구하였다. 이를 위하여 퍼스널 모빌리티에 사용되는 360 Wh급 리튬이온 배터리 팩의 배터리 셀 배열을 4가지 경우로 변경하고, 배터리 셀 홀더에 사용되는 재질과 배터리 팩 케이스에 사용되는 재질을 각각 Polypropylene, Aluminium, Magnesium alloy로 변경하였다. 그 결과 배터리 평균 온도는 배터리 셀 배열이 Model 2 일 때 가장 낮게 예측되었으며, 배터리 셀 홀더와 배터리 팩 케이스 재질 변경에 따른 배터리 평균 온도는 대부분의 경우 Aluminium 일 때 가장 낮게 예측되었다. 퍼스널 모빌리티에 사용되는 360 Wh급 리튬이온 배터리 팩의 열전달 성능은 배터리 셀 배열과 배터리 팩 케이스 재질에 많은 영향을 받았으며, 배터리 셀 배열 Model 2와 배터리 팩 케이스 재질이 Aluminium 일 때 가장 높았다.

• 한국가시화정보학회지
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• 제21권2호
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• pp.34-45
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• 2023

When lithium-ion batteries operate out of the proper temperature range, their performance can be significantly degraded and safety issues such as thermal runaway can occur. Therefore, battery thermal management systems are widely researched to maintain the temperature of Li-ion battery cells within the proper temperature range during the charging and discharging process. This study investigates the cooling performance and isothermal maintenance of cooling materials by measuring the surface temperature of a battery cell with or without cooling materials, such as silicone oil, thermal adhesive, and phase change materials during discharge process of battery by the experimental and numerical analysis. As a result of the experiment, the battery pack filled with phase change material showed a temperature reduction of 47.4 ℃ compared to the case of natural convection. It proves the advanced utility of the cooling unit using phase change material that is suitable for use in battery thermal management systems.

• 전력전자학회논문지
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• 제9권2호
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• pp.187-193
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• 2004

PDA, 스마트폰, USP 및 전기자동차와 같은 전기적 장치의 전력공급을 위하여 배터리가 직렬로 연결된 다중 셀을 만들어 일반적으로 사용한다. 이 경우 개별 셀 전압의 편차가 발생되면 배터리의 수명과 용량은 낮아지게 된다. 셀에서 전압의 안정화상태를 유지하기 위한 셀 전압을 안정화시키는 효율적인 방범은 없어서는 안 될 중요한 사항이다. 본 논문에서는 휴대형 가전기기에 적용하기 위해 마이크로컨트롤러를 사용한 다중 셀용 밸런싱 회로의 설계에 대하여 제안한다. 밸런싱 시스템은 충전되는 주기 동안 밸런싱 동작을 이행하며 마이크로컨트롤러로서 제어된다. 제안된 방법은 충전기와 레코드를 사용하여 실험을 통해 증명하였다. 실험결과에서 개별 배터리의 용량, 수령, 성능이 향상됨을 보여준다.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.631-640
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• 2016

A dual-mode power management for a hybrid-electric UAV with a cruise power of 200W is proposed and empirically verified. The subject vehicle is a low-speed long-endurance UAV powered by a solar cell, a fuel cell, and a battery pack, which operate in the same voltage bounds. These power sources of different operational characteristics can be managed in two different methods: passive management and active management. This study proposes a new power management system named PMS2, which employs a bypass circuit to control the individual power sources. The PMS2 normally operates in active mode, and the bypass circuit converts the system into passive mode when necessary. The output characteristics of the hybrid system with the PMS2 are investigated under simulated failures in the power sources and the conversion of the power management methods. The investigation also provides quantitative comparisons of efficiencies of the system under the two distinct power management modes. In the case of the solar cell, the efficiency difference between the active and the passive management is shown to be 0.34% when the SOC of the battery is between 25-65%. However, if the SOC is out of this given range, i.e. when the SOC is at 90%, using active management displays an improved efficiency of 6.9%. In the case of the fuel cell, the efficiency of 55% is shown for both active and passive managements, indicating negligible differences.

• 한국산업융합학회 논문집
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• 제27권5호
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• pp.1303-1317
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• 2024

The development of high-performance underwater propulsion devices has gained importance with the expansion of recreational and industrial diving applications. This study aims to develop and validate a waterjet-type diver propulsion system capable of achieving a top speed of 3.8 knots and an operational time of over 120 minutes. Utilizing advanced modeling and simulation techniques, the design focuses on minimizing hydrodynamic resistance and optimizing buoyancy. Structural and fluid dynamic analyses were conducted to ensure the device's stability and performance under 20 atm pressure at a depth of 200 meters. The propulsion system employs a sensorless BLDC motor and a 36V lithium-ion battery pack to enhance efficiency and reliability. Field tests confirmed an average speed of 3.88 knots and a continuous operation time of 150 minutes, exceeding the initial targets. This research demonstrates significant advancements in diver propulsion technology, providing valuable insights for future underwater equipment development. The outcomes are poised to enhance the safety, efficiency, and usability of diver propulsion devices, with broader applications in marine research, environmental monitoring, and resource exploration.

• 한국태양에너지학회 논문집
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• 제40권3호
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• pp.21-31
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• 2020

The government mandates gradually zero energy building and Photovoltaic power generation systems installed in buildings are emerging as the most realistic alternative to increase the independence rate of building energy. In this study, we propose a method to reduce the power consumption of households by increasing the PV capacity of balconies and applying the method used the charged electric power stored in batteries after sunset. In order to evaluate the electric power energy savings of the residential BESS, a balcony PV 1.2 kW and a battery pack 2 kWh were installed for 9 houses in 4 apartments in Seoul and Gyeonggi-do. The BESS is charged when the balcony PV is generated electric power, and when solar power generation is finished, it supplies power to the electric appliances connected to the load. As a result of installing the solar PV module 1.2 kW and 2 kWh class BESS for 3 households located in Seoul and Gyeonggi-do, the average electric power consumption saving rate was 40%. The reduction in electricity consumption in the case of zero generation surplus power by maximizing the utilization rate of BESS has been improved to about 53%. Therefore, in order to increase the self-sufficiency rate of electric energy in apartment houses, it is effective to increase the solar photovoltaic capacity of the balcony and apply the residential BESS. In the future, it is believed that the balcony PV and home BESS will play a key role in achieving mandatory zero-energy housing.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.9-15
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• 2024

In this study, the mechanical properties of friction stir welded A6061-T6 were evaluated. This material is used as a battery pack case material for electric vehicles. The Vickers hardness, tensile strength, and yield stress of the friction stir welding (FSW) specimen were all smaller than those of the base metal specimen. As the heat input increased, the nugget zone widened, and there were differences in hardness according to the base metal zone, heat affected zone, thermal-mechanical affected zone, and nugget zone. Mechanical properties were not proportional to heat input, and the thermal-mechanical affected zone on the advancing side was the smallest in all conditions. This is because the material flow speed increased on the advancing side, where the welding direction and the tool rotation direction were the same, forming a distinct boundary with mechanical deformation.