• 제목/요약/키워드: Electric Charge-discharge

검색결과 242건 처리시간 0.025초

Synthesis and Characterization of Silver Vanadium Oxide as a Cathode for Lithium Ion Batteries

  • Nguyen, Van Hiep;Gu, Hal-Bon
    • Transactions on Electrical and Electronic Materials
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    • 제17권3호
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    • pp.139-142
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    • 2016
  • β-AgVO3 nanorods have been successfully synthesized using a soft chemistry route followed by heat treatment. They were characterized by X-ray diffraction and field emission scanning electron microscopy, and their electrochemical properties were investigated using cyclic voltammetry, impedance spectra, and charge-discharge tests. The results showed that the smooth-surfaced nanorods are very uniform and well dispersed, with diameters of ~100-200 nm and lengths of the order of several macrometers. The nanorods deliver a maximum specific discharge capacity of 275 mAh g-1 at 30 mA g-1. They also demonstrated good rate capability with a discharge capacity at the 100th cycle of 51 mAh g-1.

W·Co의 함유량이 방전가공에 미치는 영향에 관한 연구 (A Study of Effect W·Co Content of Electrode in EDM)

  • 김용명;김희남
    • Design & Manufacturing
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    • 제2권5호
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    • pp.39-42
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    • 2008
  • The Paper discussed the effects of working electric current and pulse when using super hardend alloy drill as corona electrode. The discharge effect can be obtained very precisely in the ranges of 1A - 2A in working current. $12{\mu}s-14{\mu}s$ in dis charge pulse on time width and $8{\mu}s-10{\mu}s$ in discharge pulse off time.

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국산유기절연재료의 Treeing현상 (Treeing Phenomena in the Home-made Solid Organic Insulating Materials)

  • 성영권;이헌용;이계호;유기한
    • 전기의세계
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    • 제26권2호
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    • pp.57-65
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    • 1977
  • In roder to investigate the influence of treeing on electric breakdown of solid organic insulator the initiation and growing mechanism of tree itself, and the correlation between corona discharge and treeing phenomena in solid orgainc insulating materials, several experiments were carried out by means of needle test on polymethyl-methacrylate. The obtained results showed that the existence of voids in specimen had important effects on initiation voltage of trees and, when the direct voltage was applied, the initiation voltage of trees increased by space charge effect. And also the stagnation phenomena due to the transfer of vacancy cluster or polymekr cage in specimen might beconsidered in process of growth of trees, and corona discharge seemed to be the pre-phenomena of treeing because trees were normally initiated by internal discharge in voids.

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전기자동차 충·방전제어 통합 환경을 고려한 전기차 1차 주파수 회복예비력의 계통연계형 모델링 (Gird Connected Modeling of Primary Frequency Recovery Reserve Provided by Electric Vehicle Considering Characteristics of Electric Vehicle Charge/Discharge Control Integrated Environment)

  • 국경수;이지훈;문종희;최우영;박기준;장동식
    • KEPCO Journal on Electric Power and Energy
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    • 제7권2호
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    • pp.249-254
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    • 2021
  • As the spreading speed of electric vehicles increases rapidly, those are expected to be able to use them as flexible resources in the power system beyond the concern for the supply of its charging power. Especially when the Renewable Energy sources (RES) which have no intrinsic control capability have replaced the synchronous generators more and more, the power system needs to secure the additional frequency control resources to ensure its stability. However, the feasibility of using electric vehicles as the frequency control resources should be analyzed from the perspective of the power system operation and it requires the existing simulation frameworks for the power system. Therefore, this paper proposes the grid connected modeling of the primary frequency control provided by electric vehicles which can be integrated into the existing power system model. In addition, the proposed model is implemented considering technical performances constrained by the characteristics of the Vehicle-Grid Integration (VGI) system so that the simulation results can be accepted by the power utilities operating the power system conservatively.

부분방전 측정에 의한 하이브리드차량 견인전동기의 절연성능평가 (Evaluation on Insulation Performance of Traction Motors for a Hybrid Vehicle by Partial Discharge Measurement)

  • 박대원;박찬용;최재성;길경석;이강원
    • 한국철도학회논문집
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    • 제12권2호
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    • pp.249-253
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    • 2009
  • 본 논문에서는 부분방전 측정에 의한 하이브리드 차량용 견인전동기의 절연평가에 대하여 기술하였다. 부분방전법은 효과적인 비파괴시험으로 저압용 전기전자기기의 절연성능평가에 사용되어 왔다. 부분방전 측정시스템은 결합회로망, 저잡음 증폭회로 및 주변 전자회로로 구성되며, 주변 잡음의 영향을 최소화하기 위하여 차폐함내에 설치하였다. 교정실험으로부터 부분방전 측정시스템의 주파수 대역은 $1[MHz]{\sim}30[MHz]$ (-3[dB]), 감도는 19[mV/pC]로 평가되었다. 기사용 전동기와 신품 전동기에서 방전개시전압(DIV)과 겉보기 전하량(q)을 측정한 결과, 기사용 전동기의 방전개시전압은 $1,100[V_{rms}]$, 겉보기 전하량은 105[pC], 신품 전동기에서의 방전개시전압은 $1,400[V_{rms}]$, 겉보기 전하량은 84[pC]이었다. 방전개시전압과 전하량을 비교함으로써 견인전동기의 절연상태를 평가할 수 있었다.

확산 및 히스테리시스 현상을 고려한 확장칼만필터를 이용한 새로운 납축전지의 충전상태 추정방법 (Novel Estimation Technique for the State-of-Charge of the Lead-Acid Battery by using EKF Considering Diffusion and Hysteresis Phenomenon)

  • 덩반환;트란녹탐;박용진;최우진
    • 전력전자학회논문지
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    • 제19권2호
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    • pp.139-148
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    • 2014
  • State-of-charge (SOC) is one of the significant indicators to estimate the driving range of the electric vehicle and to control the alternator of the conventional engine vehicles as well. Therefore its precise estimation is crucial not only for utilizing the energy effectively but also preventing critical situations happening to the power train and lengthening the lifetime of the battery. However, lead-acid battery is time-variant, highly nonlinear, and the hysteresis phenomenon causes large errors in estimation SOC of the battery especially under the frequent discharge/charge. This paper proposes a novel estimation technique for the SOC of the Lead-Acid battery by using a well-known Extended Kalman Filter (EKF) and an electrical equivalent circuit model of the Lead-Acid battery considering diffusion and hysteresis characteristics. The diffusion is considered by the reconstruction of the open circuit voltage decay depending on the rest time and the hysteresis effect is modeled by calculating the normalized integration of the charge throughput during the partial cycle. The validity of the proposed algorithm is verified through the experiments.

상용자동차용 직·병렬 AGM 배터리 시스템의 충·방전 거동 모델링 (Modeling of the charge and discharge behavior of the 2S2P(2 series-2 parallel) AGM battery system for commercial vehicles)

  • 이정빈;김의성;이재신;신치범
    • 에너지공학
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    • 제21권4호
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    • pp.346-355
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    • 2012
  • 최근 전 세계가 환경문제와 에너지 자원 고갈 문제에 대해 관심을 집중하고 있다. 이런 문제들을 해결하기 위한 여러 가지 방법들 중 하나가 하이브리드자동차(HEVs)이다. 그래서 하이브리드자동차 기술에 대한 사람들의 관심이 높아지고 있다. 하이브리드 자동차의 에너지 저장 시스템의 후보들은 AGM 배터리, Ni-MH 배터리 및 리튬배터리 등이다. AGM 배터리는 상대적으로 낮은 가격, 높은 충전 효율, 낮은 자가 방전 및 높은 안전성 등이 장점이다. 상용자동차에 하이브리드 자동차 시스템을 적용하기 위해서는 4개의 AGM 배터리를 2개의 직렬과 2개의 병렬로 연결해야한다. 본 연구에서는 상용차용으로 사용될 직 병렬로 연결되어 있는 AGM 배터리 시스템의 충 방전 특성을 예측하기 위하여 AGM 배터리의 충 방전 모델링을 수행하였다. AGM 배터리의 충 방전 모델링을 위해 내부에서 일어나는 전기화학 반응, 전하 보전과 물질 보존 법칙을 통해 배터리의 지배방정식으로 세웠다. 모델링 결과의 정확성을 검증하기 위해 다양한 조건에서의 실험결과와 비교하였다.

Sand-Blasting법을 이용한 활물질/기판간 결합력 향상에 따른 AGM 연축전지의 성능 및 충방전 거동 (Performance and Charging-Discharging Behavior of AGM Lead Acid Battery according to the Improvement of Bonding between Active Material/Substrate using Sand-Blasting Method)

  • 김성준;임태섭;김봉구;손정훈;정연길
    • 한국재료학회지
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    • 제31권2호
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    • pp.75-83
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    • 2021
  • To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 ℃ and 30 ℃ with high current, the advanced AGM LAB improves about 25 %. At 0 ℃ CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

절연유의 교류부분방전에 미치는 첨가물의 영향에 관한 연구 (A study on effect of additives upon A.C. partial discharge in insulating oil)

  • 국상훈
    • 전기의세계
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    • 제29권8호
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    • pp.532-537
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    • 1980
  • Effect of Argon and Sulfur hexafloride in the transformer oil are experimented under non-uniform A.C. electric field. The result has shown that the corona frequency and corona charge quantity in liquid dielectrics were varied with gas condition in the oil and affected by the additives. SF$_{6}$ that has the effects of pressure and electrical negative characteristic is the most effective. The corona is considered to be the breakdown of bubble produced by gas contained in the oil or by dissociated ion of the oil molecules.s.

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초소형 플라이휠 에너지 저장장치의 설계 (Design of Micro Flywheel Energy Storage System)

  • 이지은;유승열;노명규
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.879-884
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    • 2007
  • Flywheel energy storage systems have advantages over other types of energy storage devices in such aspects as unlimited charge/discharge cycles and environmental friendliness. In this paper we propose a millimeter scale flywheel energy storage device. The flywheel is supported by a pair of passive magnetic bearings and rotated by a toroidally wound electric motor/generator. The geometry of the bearings is optimized for the maximum dynamic performance.

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