• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 추계학술대회
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• pp.224-225
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• 2019

본 논문은 에너지 절약을 위한 특정 상업용 에너지 저용량 에너지저장시스템 모델 개발 및 연구를 수행하였다. 저용량 에너지저장시스템은 피트니스센터의 스피닝 기계에의 적용을 목적으로 하고 있으며 제안하는 시스템은 BLDC모터, Rectifier, DC-DC Coverter, Controller, Battery 로 구성되어 있다. 본 논문에서는 각 구성요소간의 직병렬 연결을 통하여 저용량 에너지저장시스템의 효율적인 운영방안을 제시한다. 제안하는 저용량 에너지저장시스템은 시뮬레이션을 통하여 모델링 및 결과 분석을 진행하였다.

• 전기학회논문지
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• 제65권7호
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• pp.1161-1168
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• 2016

Battery energy storage system(BESS) attract the attention of the power system operators with its fast response to a disturbance in spite of its limited energy capacity. This paper proposes the operating method of BESS for following the Automatic Generation Control(AGC) frequency control which is centrally distributed by a system operator. As BESS needs to just meet the control requirement from the system operator, it should be able to properly manage the state of charge(SOC) of BESS to be available to control signal. For doing these, the proposed method distributes the control requirement to available batteries in proportion to its SOC. In addition, unavailable batteries are controlled to recover the SOC to an appropriate range, and the recovering power is supplied by available batteries meeting the control requirement. Moreover, the proposed method manages the efficiency of power conversion system (PCS) by limiting the number of PCS to be assigned for the low control requirement. Finally, the case studies are carried out to verify the effectiveness of proposed strategy.

• 전기학회논문지
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• 제65권7호
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• pp.1169-1175
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• 2016

As an Increased penetration level of renewable resources has caused concerns about primary frequency response, an increase in BESS(Battery Energy Storage System) capacity has been expected because of its fast response to the disturbances in the power system. This paper proposes the Integrated Control Strategy of multiple BESS for effectively providing the primary frequency control in the bulk power systems by coordinating the response, SOC and its recovery of BESS. The proposed strategy prevents multiple BESS from providing exceeding response and keeps the balance between SOC of multiple BESS. In addition, It would recover the SOC of BESS efficiently. The effectiveness of the proposed strategy is verified through various case studies employing Korean power system.

• 한국수소및신에너지학회논문집
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• 제2권1호
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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 $25^{\circ}C$.

• KEPCO Journal on Electric Power and Energy
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• 제6권2호
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• pp.119-122
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• 2020

With recent ESS (Energy Storage System) fire accident, the fault protection performance is becoming more important. However, there has never been any experiments with the protection performance on the faults in the ESS system level. In this study, the effect of AC ground fault and IGBT (Insulated Gate Bipolar mode Transistor) short-circuit failure on MW class ESS was performed experimentally for the first time in the world. First of all, the effect of the AC single line ground fault on battery was analyzed. Moreover, the transient voltage was investigated as a function of the battery capacity and the power level. Finally, the breaking capability and insulation performance of ESS were examined under PCS short-circuit fault condition. Through the tests, it was found that ESS protection system safely blocked the faulty current regardless of the faults, whereas the electronic parts such as IGBT and MC (Magnetic Contactor) were broken by the fault current. Also, the electrical breakdown in ESS resulted from the transient voltage during the protection process.

• Journal of Electrochemical Science and Technology
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• 제10권1호
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• pp.1-13
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• 2019

Na-ion batteries are being considered as promising cost-effective energy storage devices for the future compared to Li-ion batteries owing to the crustal abundance of Na-ion. However, the large radius of the Na ion result in sluggish electrode kinetics that leads to poor electrochemical performance, which prohibits the use of these batteries in real time application. Therefore, identification and optimization of the anode, cathode, and electrolyte are essential for achieving high-performance Na-ion batteries. In this context, the current review discusses the suitable high-voltage cathode materials for Na-ion batteries. According to a recent research survey, sodium vanadium fluorophosphate (NVPF) compounds have been emphasized for use as a high-voltage Na-ion cathode material. Among the fluorophosphate groups, $Na_3V_2(PO_4)_2F_3$ exhibited the high theoretical capacity ($128mAh\;g^{-1}$) and working voltage (~3.9 V vs. $Na/Na^+$) compared to the other fluorophosphates and $Na_3V_2(PO_4)_3$. Here, we have also highlighted the classification of Fluorophosphates, NVPF composite with carbonaceous materials, the appropriate synthesis methods and how these methods can enhance the electrochemical performance. Finally, the recent developments in NVPF for the application in energy storage devices and its outlook are summarized.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.598-598
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• 2012

Rechargeable lithium-ion batteries have been considered the most attractive power sources for mobile electronic devices. Although graphite is widely used as the anode material for commercial lithium-ion batteries, it cannot fulfill the requirement for higher storage capacity because of its insufficient theoretical capacity of 372 mAh/g. For the sake of replacing graphite, Sn-based materials have been extensively investigated as anode materials because they can have much higher theoretical capacities (994 mAh/g for Sn, 875 mAh/g for SnO, 783 mAh/g for $SnO_2$). However, these materials generate huge volume expansion and shrinkage during $Li^+$ intercalation and de-intercalation and result in the pulverization and cracking of the contact between anode materials and current collector. Therefore, there have been significant efforts of avoiding these drawbacks by using nanostructures. In this study, we present the CVD growth of SnO branched nanostructures on Cu current collector without any binder, using a combinatorial system of the vapor transport method and resistance heating technique. The growth mechanism of SnO branched nanostructures is introduced. The SnO nanostructures are evaluated as an anode for lithium-ion battery. Remarkably, they exhibited very high discharge capacities, over 520mAh/g and good coulombic efficiency up to 50 cylces.

• 전력전자학회논문지
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• 제4권2호
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• pp.215-222
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• 1999

전기에너지의 저장은 발전효율면이나 전력의 품질향상 등 전력시스템에서 뚜렷한 장점을 가지고 있다. 초전도 에너지 저장장치는 전기에너지를 저장할 수 있는 설비의 하나로 높은 효율과 속응성, 긴 수명 등의 특성으로 전력시스템 적용시 곧 이루어지리라 예상된다. 본 논문에서는 SMES의 국내도입시 필요한 투자정보를 제공하기 위한 최적규모 산정의 알고리즘을 제안한다. 제안한 알고리즘은 SMES의 경제적 운전 양상을 결정하는 확률적 운전모형과 최대원리를 이용한 투자계획모형으로 구성되어 있다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.981-987
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• 2017

In this paper, we estimate the economic benefits of Energy Storage Systems (ESSs) for peak load shaving in an urban railway substation using the annual cost. The annual investment cost of ESSs is estimated using Net Present Value (NPV) and compared with the cost reduction of electricity by the ESS. The optimal capacities of the battery and Power Converting System (PCS) are determined for peak load shaving. The optimal capacity of the ESS and the peak load shaving is determined to maximize the profit by the ESS. The proposed method was applied to real load data in an urban railway substation, and the results show that electric power costs can be reduced. Other aspects of the ESS, such as the lifetime and unit price of the battery, are also investigated economically.

• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.90-99
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• 2022

Owing to the rising concern of global warming, lithium-ion batteries have gained immense attention over the past few years for the development of highly efficient electrochemical energy conversion and storage systems. In this study, alpha-phase VOPO₄·2H₂O with nanosheet morphology was prepared via a facile hydrothermal method for application in high-performance lithium-ion batteries. The X-ray diffraction and scanning electron microscopy (SEM) analyses indicated that the obtained sample had an alpha-2 (αII) phase, and the nanosheet morphology of the sample was confirmed using SEM. The lithium-ion battery with VOPO₄·2H₂O as the anode exhibited excellent long-term cycle life and a high capacity of 256.7 mAh g^-1 at room temperature. Prelithiation effectively improved the specific capacity of pristine VOPO₄·2H₂O. The underlying electrochemical mechanisms were investigated by carrying out AC impedance, rate capability, and other instrumental analyses.