• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.133-135
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• 2020

배터리의 가용 영역에 따른 효율적인 운영 방법을 판단하기 위해 방전 깊이(Depth of Discharge; DOD)에 따라 배터리의 노화 상태 및 에너지를 계산하여 최적의 가용 영역을 판단한다. 배터리의 상태를 판단하기 위한 지표로써 건강 상태(State of Discharge; DOD)와 출력 상태(State of Power; SOP)의 분석을 통해 비교한다. 노화 파라미터 및 DOD에 따른 노화 차이를 반영한 알고리즘 구현 및 배터리팩과 시스템 레벨의 효율적인 운영 방안에 관해 연구한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.15-20
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• 2018

This paper presents the method of ESS energy capacity calculation for stand-alone renewable energy generation system consisting of photovoltaic energy. There is almost no power from photovoltaic system during sunless days. So this source is very weak in terms of the power supply reliability. To improve problem of power supply, battery is mainly used Energy Storage System(ESS). The number of sunless days and Depth of Discharge(DOD) is important factor to determine energy capacity of battery. However, a many study for economical design is required due to the high cost of ESS. In this paper, we propose the new method of ESS energy capacity calculation by applying different DOD for operation with and without sun. We determine the Battery capacity using higher DOD of operation during sunless day than the DOD of the normal operation. And we carried out an economic analysis of the calculation results.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1173-1184
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• 2018

The lifetime of a lithium-ion battery is one of the most important issues of the energy storage system (ESS) because of its stable and reliable operation. In this paper, the lifetime management method of the lithium-ion battery for energy storage system is proposed. The lifetime of the lithium-ion battery varies, depending on the power usage, operation condition, and, especially the selected depth of discharge (DOD). The proposed method estimates the total lifetime of the lithium-ion battery by calculating the total transferable energy corresponding to the selected DOD and achievable cycle (ACC) data. It is also demonstrated that the battery model can obtain state of charge (SOC) corresponding to the ESS operation simultaneously. The simulation results are presented performing the proposed lifetime management method. Also, the total revenue and entire lifetime prediction of a lithium-ion battery of ESS are presented considering the DOD, operation and various condition for the nations of USA and Korea using the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.85-94
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• 2015

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.84-96
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• 2002

The major goal of this research is to use as a baseline guide for a flight model design of power system of next domestic communication satellite. For this purpose, the EPS(Electrical Power Subsystem) is designed to compliance performance requirements specified in EPS subsystem specification during all expected spacecraft operations. The regulated electrical power bus gives 42.5V to the various spacecraft loads from PCDU(Power Control & Distribution Unit) and the solar arrays are composed of 6 panel, each panel has 3 circuits including 7 string. The battery system is comprised of two batteries consisting of 26 IPV(Individual-Pressure-Vessel) NiH2 cells. Each battery can be capable of delivering 2878Watt-hours at a 80% maximum DOD(Depth of Discharge) based on the nameplate capacity of 150 amper-hours.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.47-48
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• 2017

This paper presents a low-cost portable lithium battery parameter measuring and estimating the solution. In this method, lithium battery characteristics are monitored during discharging and charging cycles. The battery profile is analyzed, and its key parameters are estimated by GNU Octave running on Raspberry Pi Zero, a mini computer. The proposed method can measure and estimate the battery parameters for SOC and DOD estimation with reasonable accuracy as well as portability features.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.529-536
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• 2015

With the growing interest of microgrid all over the world, many studies on microgrid operation are being carried out. The battery energy storage system(BESS) is a key equipment for effective operation of the microgrid. In this paper, we analyze the characteristics of the charge and discharge output voltage of the battery and the characteristics of the life-span variation and the investment cost when the state-of-charge (SOC) changes. The formulas to represent the quality of the charge and discharge output voltage of the battery and the economics due to the life-span variation and the investment cost according to DOD(Depth of Discharge) are derived. The methodology of determining the proper operation ranges of the battery SOC with varying the weighting of the quality of its charge and discharge output voltage of the battery and the economics due to its life-span variation and the investment cost is presented using these formulas.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.950-956
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• 2012

As development of battery technologies, the installation of Battery Energy Storage System (BESS) increased. The BESS can be used for various purposes such like frequency response, load leveling, and fluctuation mitigation of renewable energy generators. In this paper, three state BESS model is proposed. the BESS model considering charge, discharge and keeping efficiency, and life cycle according to depth of discharge (DOD). Then, the benefit and cost of BESS installed at substation for load leveling are summarized. The economic evaluation of BESS is analyzed using net present values (NPV) analysis. In case study, the NPV analysis of NaS battery system is carried out using the proposed BESS model. Because the result of economic evaluation of BESS using nowadays cost data is not positive, the sensitivity analysis of BESS is conducted by changing the capital cost and energy cost.

• Journal of Hydrogen and New Energy
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• v.2 no.1
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• pp.15-21
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• 1990

Nickel-hydrogen battery systems with metal hydride alloys are expected to have both higher energy density and lower pollution than nickel-cadmium cells. Nickel-hydrogen storage cells are expected to be well-suited for use in space crafts for a large capacity power storage system. Their major advantages are not only a capability of deep DOD(depth of discharge) using but also with excellent durability under excessive overcharging and overdischarging. In this study, the charge/discharge capacities, anodic polarization characteristics and durability for the continious charge/diacharge cycling of the $Ti_{1-X}Zr_XVNi$ and $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were measured by electrochemical method. The electrode properties of the copper or nickel plated $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were examined with a battery charge/discharge testing system in the temperature range of -5 to $25^{\circ}C$.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.269-270
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• 2010

본 논문은 리튬 폴리머 배터리(LiPB)의 OCV(Open Circuit Voltage;개방전압)를 이용한 배터리 SOH(State Of Health;잔존수명) 추정하는 방법의 제안이다. 종래에는 배터리 수명은 제조회사에서 지정된 시간이나 충방전 횟수를 기초로 수명을 결정하였다. 하지만 배터리의 온도, 충전방법, 전류변화 및 DOD(Depth of Discharge;방전심도) 정도에 따라 배터리 수명은 유동적이다. 따라서 배터리가 노후됨에 따라 OCV가 변한다는 원리를 이용하여 임피던스 분석을 통해서 SOH, 즉 배터리 잔존수명을 추정하는 기술을 제안하였다.