The Correlation Between Charge and Discharge Current for the Electrochemical Stability and Durability of Electrolyte in a Vanadium Redox Flow Battery

김동현,우유한,전준현 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.9

The object of this paper is to simulate electrochemical performances of V-electrolyte employed in the VRFB cell when different charge/discharge current densities are given. Experimental results show that increasing charge(or discharge) current for a given discharge (or charge) current leads to the reduction of both voltaic efficiency and charge(or discharge) capacity as compared to the use of same charge/discharge currents, while resulting in coulombic efficiency improvement. In contrast, the decreasing cases provide the improvement of both the voltaic efficiency and the capacity, but there takes place a serious problem of the capacity fading effect as well as the coulombic efficiency reduction. This is because low charge/discharge current densities causes polarization effects and self-discharges during cyclic operation, resulting in electrochemical instability of electrolyte performance. Consequently, both the charge and discharge current densities have to be employed over 80 mA/cm2 to keep an electrochemical stability of electrolyte.

A New Simple-Structured Thyristor Hybrid DC Circuit Breaker

Park Sung-Hyeon,Kim Juwon,Kim In-Dong 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.6

The wide utilization of DC system has made a DC circuit breaker become indispensable in order to limit or block fault current. HDCCB (Hybrid DC Circuit Breaker) has been studied and developed which combines good features of a mechanical circuit breaker and a solid-state circuit breaker. This paper propose a new simple-structured thyristor hybrid DC circuit breaker. The proposed thyristor HDCCB making use of an inverse current injecting method has the natural charging and discharging features of the commutation capacitor, and consequently blocking the fault current. Furthermore, it can rapidly perform the re-closing and re-breaking of operating duty in addition to the interruption operation of fault currents. A prototype of proposed hybrid DC circuit breaker was designed and fabricated, and its operating features were proven through simulation results and experimental ones.

A Study on the Charging and Diagnosis System of xEV Reusable Waste Battery

Park, Sung-Jun,Kim, Chun-Sung,Park, Seong-Mi The Korean Society of Industry Convergence 2021 한국산업융합학회 논문집 Vol.24 No.6

As the supply of xEV in Korea is rapidly increasing, the amount of waste batteries is expected to increase rapidly, but the current recycling system for waste xEV batteries is very insufficient. In order to properly utilize the xEV reusable battery module, it is essential to classify it into a type that has similar discharge characteristics to the current state of health(SOH), which is the discharge capacity of the battery. This paper proposes a system that can minimize the exchange of energy with the KEPCO system by using the charging/discharging method by circulating power between batteries in order to minimize the power consumption when charging and discharging waste batteries. In the proposed system, a function to measure parameters during the charging/discharging test of the waste battery was implemented to build a customized big date for the test waste battery. In addition, the dynamic characteristics of the proposed circuit were analyzed using PSIM, which is useful for power electronics analysis, and the validity of the proposed circuit was verified through experiments.

하이브리드형 슈퍼커패시터의 실험적 특성 규명

정규원(Kyuwon Jeong),신재열(Jaeyoul Shin) 한국생산제조학회 2016 한국생산제조학회지 Vol.25 No.4

Several types of supercapacitors have been developed for energy storage systems. Among them, the hybrid type has advantages such as a large capacitance per weight compared with the electric double-layer capacitator type. In this study, constant current charging and discharging tests were conducted for recently developed hybrid-type supercapacitors. Based on the experimental results, the capacitance and equivalent series resistance were obtained. The capacitance was larger than the designed capacitance at a low current but became small at a high current. In addition, the capacitance depended on the cell voltage. These results can be used to design an energy storage system.

와이어 전극과 평행판에서 발생되는 이온풍 특성 연구

안영철,황필재,이재근 대한설비공학회 2004 설비공학 논문집 Vol.16 No.4

When a strong electric field is applied between a sharply curved electrode and a blunt surface, the corona may result in a gas movement in the electrode gap which is directed toward the blunt surface. That is called the corona wind. It enhances heat and mass transfer between the surface and the surrounding gas. Moreover such enhancement causes no noise or vibration, which can be applied in complex, isolated geometries, and allows simple control of surface temperatures. This paper examines the relationship between the corona wind and the relative humidity. The facility consists of high voltage power supply, thin tungsten wire, plate electrode, multimeter, microammeter and flow meter. Gas velocity is a linear function of voltage, relative humidity and is proportional to the square root of the current. The maximum velocities for the positive and negative corona discharge are 1.9 m/s (2.74 CMM/m), 1.5 m/s (2.15 CMM/m), respectively.

Modeling of Battery for EV using EMTP/ATPDraw

Kim, Jun-Hyeok,Lee, Soon-Jeong,Kim, Eung-Sang,Kim, Seul-Ki,Kim, Chul-Hwan,Prikler, Laszlo The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

As environmentally friendly energy takes center stage, interests for Electric Vehicles/Plug in Hybrid Electric Vehicles (EVs/PHEVs) are getting increase. With this trend, there is no doubt EVs will take large portion to penetrations of total cars. Therefore, accurate EV modeling is required. Battery is one of the main components with the power system view of aspect. Hence, in this paper, reviews and discussions of some types of batteries for EV are contained by considering energy density and weight of the batteries. In addition, simulations of Li-Ion battery are accomplished with various variables such as temperature, capacity fading and charge/discharge current. It is confirmed that temperature is the main factor of capacity fading. Validation of the modeled battery is also conducted by comparing it with commercialized battery.

정지궤도위성의 배터리 충/방전 전류 원격 측정 선별 알고리즘의 설계

박정언(Jeongeon Park),구자춘(Jachun Koo),장진백(Jinbaek Jang) 한국항공우주학회 2016 한국항공우주학회 학술발표회 논문집 Vol.2016 No.11

Modeling of Battery for EV using EMTP/ATPDraw

Jun-Hyeok Kim,Soon-Jeong Lee,Eung-Sang Kim,Seul-Ki Kim,Chul-Hwan Kim,Laszlo Prikler 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

As environmentally friendly energy takes center stage, interests for Electric Vehicles/Plug in Hybrid Electric Vehicles (EVs/PHEVs) are getting increase. With this trend, there is no doubt EVs will take large portion to penetrations of total cars. Therefore, accurate EV modeling is required. Battery is one of the main components with the power system view of aspect. Hence, in this paper, reviews and discussions of some types of batteries for EV are contained by considering energy density and weight of the batteries. In addition, simulations of Li-Ion battery are accomplished with various variables such as temperature, capacity fading and charge/discharge current. It is confirmed that temperature is the main factor of capacity fading. Validation of the modeled battery is also conducted by comparing it with commercialized battery.

EPR의 열화에 의한 충.방전 전류 특성에 관한 연구

이성일,Lee, Sung-Ill 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.7

This paper describes the degraded properties of between the charge and discharge current for ${\gamma}$-ray irradiated in electric power cable rubbers using in nuclear power generating station. The charge and discharge current of degradation in EPR(Ethylene Propylene Rubber), which were irradiated with the radiant capacity of 0.033 Mrad/h, have been measured in order to investigate the influence of the atmosphere(in amount of reinforcing agent, moisture absorption and heat treatment) on electrical properties. When ${\gamma}$-ray were irradiated on the EPR with more reinforcing agent from 4 to 40 Phr, charge and discharge currents was increase due to the amount of reinforcing agent. It was verified that the discharging and charging currents irradiated by ${\gamma}$-ray were higher than those that was not irradiated. The amount of the degraded current was more after moisture absorption than before moisture absorption. The charge and discharge current after heat treatment was similar to that of before heat treatment and it was decreased with the time elapsed. As these properties related with ${\gamma}$-ray irradiation dose, it is suggested that these properties can be utilized as a index of irradiation degradation.

Effect of Deposition Parameters on the Morphology and Electrochemical Behavior of Lead Dioxide

Hossain, Md Delowar,Mustafa, Chand Mohammad,Islam, Md Mayeedul The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.3

Lead dioxide thin films were electrodeposited on nickel substrate from acidic lead nitrate solution. Current efficiency and thickness measurements, cyclic voltammetry, AFM, SEM, and X-ray diffraction experiments were conducted on $PbO_2$ surface to elucidate the effect of lead nitrate concentration, current density, temperature on the morphology, chemical behavior, and crystal structure. Experimental results showed that deposition efficiency was affected by the current density and solution concentration. The film thickness was independent of current density when deposition from high $Pb(NO_3)_2$ concentration, while it decreased for low concentration and high current density deposition. On the other hand, deposition temperature had negative effect on current efficiency more for lower current density deposition. Cyclic voltammetric study revealed that comparatively more ${\beta}-PbO_2$ produced compact deposits when deposition was carried out from high $Pb(NO_3)_2$ concentration. Such compact films gave lower charge discharge current density during cycling. SEM and AFM studies showed that deposition of regular-size sharp-edge grains occurred for all deposition conditions. The grain size for high temperature and low concentration $Pb(NO_3)_2$ deposition was bigger than from low temperature and high concentration deposition conditions. While cycling converted all grains into loosely adhered flappy deposit with numerous pores. X-ray diffraction measurement indicates that high concentration, high temperature, and high current density favored ${\beta}-PbO_2$ deposition while ${\alpha}-PbO_2$ converted to ${\beta}-PbO_2$ together with some unconverted $PbSO_4$ during cycling in $H_2SO_4$.