• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.183-186
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• 2011

본 논문에서는 전기동력 추진기관을 사용하는 비행체의 추진시스템에 대하여 분석하고, 무게분석을 통하여 PAV의 전기동력시스템을 살펴보았다. 현재 1,000 kg의 PAV를 개발할 경우 PEMFC와 리튬전지를 조합한 추진기관이 내연기관을 대체할 수 있을 것으로 예상된다. 내연기관을 대체하기 위해서는 연료전지 출력밀도 2.5 kW/kg, 배터리 에너지밀도 0.75 kWh/kg 이상의 성능이 요구된다.

• 한국기계가공학회지
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• 제21권9호
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• pp.85-91
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• 2022

The demand for electric vehicles has increased because of environmental regulations. The lithium-ion battery, the most widely used type of battery in electric vehicles, is composed of a cathode, an anode, and an electrolyte. It is manufactured according to the pole plate, assembly, and formation processes. To improve battery performance and increase manufacturing efficiency, the manufacturing process must be optimized. To do so, simulation can be used to reduce wasted resources and time, and a finite-element method can be utilized. For high simulation quality, it is essential to reflect the material properties of the electrode by considering the pores. However, the material properties of electrodes are difficult to derive through measurement. In this study, the representative volume element method, which is a homogenization method, was applied to estimate the representative material properties of the electrode considering the pores. The representative volume element method assumes that the strain energy before and after the conversion into a representative volume is conserved. The method can be converted into one representative property, even when nonhomogeneous materials are mixed in a unit volume. In this study, the material properties of the electrode considering the pores were derived. The results should be helpful in optimizing the electrode manufacturing process and related element technologies.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.118-121
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• 2023

Recently, green energy support policies have been announced around the world in accordance with environmental regulations, and asthe market grows rapidly, demand for batteries is also increasing. Therefore, various methodologies for battery diagnosis and recycling methods are being discussed, but current accurate life prediction of batteries has limitations due to the nonlinear form according to the internal structure or chemical change of the battery. In this paper, CS2 lithium-ion battery measurement data measured at the A. James Clark School of Engineering, University of Marylan was used to predict battery performance with high accuracy using a convolutional neural network (CNN) model among deep learning-based models. As a result, the battery performance was predicted with high accuracy. A data structure with a matrix of total data 3,931 ☓ 19 was designed as test data for the CS2 battery and checking the result values, the MAE was 0.8451, the RMSE was 1.3448, and the accuracy was 0.984, confirming excellent performance.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.37-45
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• 2018

전기자동차는 내연기관 자동차와는 달리 배출가스가 없어 친환경 차량을 대표하지만, 장착된 축전지에 충전된 전기로 구동되기 때문에, 1회 충전으로 갈 수 있는 거리가 전지의 에너지 밀도에 의해 좌우된다. 따라서 높은 에너지 밀도를 갖는 리튬이온 배터리가 전기구동자동차용 전지로 많이 사용하고 있다. 리튬이온 배터리의 효율을 지배하는 중요한 구성품은 전극이므로 전극 제조공정은 리튬이온 배터리 전체생산 공정에서 중요한 역할을 한다. 특히 전극의 제조 공정 중 건조공정은 성능에 큰 영향을 미치는 매우 중요한 공정이다. 본 논문에서는 전극제조에서 건조공법의 효율성 및 생산성 증대를 위한 혁신적인 공정을 제안하고, 장비 설계 방법 및 개발 결과에 대하여 기술하였다. 구체적으로, 극판 결착력 향상 기술, 대기압 과열증기 건조 기술, 그리고 건조로 폭 슬림화 기술들에 대한 설계 절차 및 개발방법을 제시하였다. 결과로 세계최초의 개방형/일체형 대기압 과열증기 Turbo Dryer 양산기술 확보를 통해 전기차 전지용 극판 고속건조기술을 확보 하였다. 기존의 건조공정과 비교할 때 건조로 길이 생산성을 향상시켰다 (건조 Lead Time 0.7분(分) ${\rightarrow}$ 0.5분(分)기준).

• 한국기계가공학회지
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• 제13권3호
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• pp.70-76
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• 2014

The intensity of sunlight becomes lower when weather conditions change, which affects whether a solar-electric vehicle can be driven on a shady road. The power delivered by solar cells can be vary depending on the amount of shade. As a result, the battery system is often used to compensate for variations in the power delivered by solar cells. Therefore, studies of power control systems for solar-electric vehicles are required. In this paper, mathematical models for such a power control system are studied and important variables are considered. Simulation and test results show that the mathematical model and actual designs developed here would be effective when used with solar-electric vehicles.

• 에너지공학
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• 제25권4호
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• pp.170-175
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• 2016

현재 자동차의 주요 동력원은 내연기관이 가장 많은 비중을 차지하고 있다. 내연기관 자동차로 인한 환경문제를 해결하기 위한 친환경 자동차로는 하이브리드 자동차, 전기 자동차 및 공기 엔진 자동차 등을 들 수 있다. 배터리를 이용하는 하이브리드 차나 순수 전기차 등도 아직은 크지 않으나 점차 많은 비중을 차지하여 나가고 있다. 전기모터를 사용하는 전기차에 비해 압축공기를 이용하는 공기 엔진 자동차는 아직은 연구개발이 거의 이루어지지 않은 상태이다. 본 논문에서는 스크롤 팽창기를 적용하는 새로운 압축공기 엔진을 소개하고, 이 엔진을 장착한 자동차의 주행거리 가능 거리를 이론적으로 산출하였다.

• Coupled systems mechanics
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• 제11권1호
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• 전기학회논문지
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• 제61권6호
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• pp.783-790
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• 2012

Electric Vehicles(EVs) and Plug-in Hybrid Electric Vehicles(PHEVs) which have the grid connection capability, represent an important power system issue of charging demands. Analyzing impacts EVs charging demands of the power system such as increased peak demands, developed by means of modeling a stochastic distribution of charging and a demand dispatch calculation. Optimization processes proposed to determine optimal demand distribution portions so that charging costs and demand can possibly be managed. In order to solve the problems due to increasing charging demand at the peak time, alternative electricity rate such as Time-of-Use(TOU) rate has been in effect since last year. The TOU rate would in practice change the tendencies of charging time at the peak time. Nevertheless, since it focus only minimizing costs of charging from owners of the EVs, loads would be concentrated at times which have a lowest charging rate and would form a new peak load. The purpose of this paper is that to suggest a scenario of load leveling for a power system operator side. In case study results, the vehicles as regular load with time constraints, battery charging patterns and changed daily demand in the charging areas are investigated and optimization results are analyzed regarding cost and operation aspects by determining optimal demand distribution portions.

• 전기화학회지
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• 제4권2호
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• pp.53-57
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• 2001

전기자동차 운용시 빈번히 발생되는 차량의 주정차기간에 축전지는 자기방전을 일으켜 용량의 손실이 발생하게 된다. 따라서 전기자동차의 잔존용량을 정확히 측정하기 위해서는 자기방전에 의한 용량손실을 고려하여야 한다. 이 논문에서는 전기자동차 운용시 빈번히 발생할 것으로 예상되는 주정차기간에 대해 포괄적으로 적용할 수 있는 Ni/MH Battery의 자기방전율을 나타내는 일반식을 전산모사 방법 중 하나인 실험계획법을 이용하여 구하였으며 이를 시험데이터와 비교하였다. 실험계획법을 위한 온도영역으로는 전기자동차가 운용되는 $-20\~30^{\circ}C$의 온도구간을 선정하였으며, 축전지의 방치시간으로는 자기방전이 상대적으로 크게 일어나며 빈번히 발생할 것으로 예상되는 영역인 1일$\~$15일 범위를 선택하였다. 이와 같은 방법으로 실험계획법에 의해 구해진 축전지 자기방전율에 대한 일반식의 타당성을 검증하기 위해 축전지에 대한 자기방전시험을 수행하여 비교하였으며, 그 결과 실험계획법으로 예측한 축전지의 자기방전율은 시험데이터와 우수한 일치를 나타내었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.429-430
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• 2011

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology with coupled inductors. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charging mode, constant-current mode, and constant-voltage mode. The pre-charging mode employs the staircase shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is able to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 67A. The optimal discharging algorithm for Vehicle to the Grid (V2G) operation has been adopted to maintain the discharging current of 1C. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.