• Title/Summary/Keyword: Battery electric vehicle

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Thermo-Fluid Simulation for Flow Channel Design of 7kW High-Voltage Heater for Electric Vehicles (전기차용 7kW급 고전압 히터 유로 형상 설계를 위한 열유동 시뮬레이션)

  • Son, Kwon Joong
    • Journal of the Korea Convergence Society
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    • v.13 no.3
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    • pp.191-196
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    • 2022
  • Unlike an international combustion engine car, a battery-powered electric vehicle requires an additional heat source for its heating system. A high-voltage coolant heater has the advantages of high efficiency and a wide operating temperature range. In its development, the geometry design of the coolant flow path is essential. This paper presents the thermal flow simulations of a 7kW high-voltage heater with symmetric serpentine flow channels arranged parallelly. The heater performance was evaluated from the simulation results in terms of the pressure and temperature differences and the flow uniformity. The proposed design showed a greater flow resistance and similar heat exchanging capability than the existing parallel serpentine design. It has the advantage of a relatively wide low-temperature surface area, where the control circuit board susceptible to high temperatures can be located.

A Study on the Fire Risk of High-voltage Cables for Electrical Vehicles (전기차용 고전압 케이블의 화재 위험성에 관한 연구)

  • Sin Dong Kang;Ye Jin Park;Si Hyun Kim;Jae-Ho Kim
    • Journal of the Korean Society of Safety
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    • v.38 no.4
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    • pp.8-14
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    • 2023
  • This study presents the characteristics of short circuits (SCs) caused by excessive currents in high-voltage cables used in electric vehicles and emphasizes the need to calculate the cross-sectional areas of these cables according to the SC current. Three direct current power supplies were connected in parallel to test the SC characteristics caused by excessive currents, and a timer and a magnetic contactor were used to deliver the conduction time and SC current. A circular infrared-radiation heater was used to test the temperature-dependent SC characteristics, a thermocouple was used to measure the temperature, and a shunt resistor was used to measure the current. As the SC current increased, the fusing time of the cable decreased. Additionally, a high-voltage cable (with an area of 16 mm2 ) used in electric vehicles fused when a current (approximately equal to 55 times the allowable current) flowed for 0.2 s (operating time of the protective device). When the SC current is 10 kA, the cable may fuse during the operating time of the protective device, thus creating a fire hazard. In electric vehicles, the size of the SC current increases in proportion to the capacity of the battery. Thus, the cross-sectional areas of the cables used should be calculated accordingly, and cable operations should be properly coordinated with the surrounding protective devices.

Electrochemical Study of Electrode Material of Ni-MH Battery for HEV and PEMFC Fuel Cell (HEV 및 PEMFC 연료전지용 니켈수소 전지의 전극재료에 대한 전기화학적 평가)

  • Kim, Ho-Sung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.2
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    • pp.24-28
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    • 2006
  • Electrochemical hydrogenation/dehydrogenation properties were studied for a single particle of a Mm-based(Mm : misch metal) hydrogen storage alloy($MmNi_{3.55}Co_{0.75}Mn_{0.4}Al_{0.3}$) for the anode of Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and the cyclic voltammetry and the galvanostatic charge/discharge experiments were performed. A single particle of the alloy showed the discharge capacity of 280[mAh/g], the value being 90[%] of the theoretical capacity. Data were compared with that of the composite film consisting of the alloy particles and a polymer binder, which is more practical form for Ni-MH batteries. Additionally, pulverization of the alloy particles are directly observed. Compared with the conventional composite film electrodes, the single particle measurements using the microelectrode gave more detailed, true information about the hydrogen storage alloy.

Analysis and Design of a Multi-resonant Converter with a Wide Output Voltage Range for EV Charger Applications

  • Sun, Wenjin;Jin, Xiang;Zhang, Li;Hu, Haibing;Xing, Yan
    • Journal of Power Electronics
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    • v.17 no.4
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    • pp.849-859
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    • 2017
  • This paper illustrates the analysis and design of a multi-resonant converter applied to an electric vehicle (EV) charger. Thanks to the notch resonant characteristic, the multi-resonant converter achieve soft switching and operate with a narrowed switching frequency range even with a wide output voltage range. These advantages make it suitable for battery charging applications. With two more resonant elements, the design of the chosen converter is more complex than the conventional LLC resonant converter. However, there is not a distinct design outline for the multi-resonant converters in existing articles. According to the analysis in this paper, the normalized notch frequency $f_{r2n}$ and the second series resonant frequency $f_{r3n}$ are more sensitive to the notch capacitor ratio q than the notch inductor ratio k. Then resonant capacitors should be well-designed before the other resonant elements. The peak gain of the converter depends mainly on the magnetizing inductor ratio $L_n$ and the normalized load Q. And it requires a smaller $L_n$ and Q to provide a sufficient voltage gain $M_{max}$ at ($V_{o\_max}$, $P_{o\_max}$). However, the primary current increases with $(L_nQ)^{-1}$, and results in a low efficiency. Then a detailed design procedure for the multi-resonant converter has been provided. A 3.3kW prototype with an output voltage range of 50V to 500V dc and a peak efficiency of 97.3 % is built to verify the design and effectiveness of the converter.

Surface Modification Technology and Research Trends of Separators for Lithium-Ion Batteries (리튬이온 전지용 분리막의 표면 개질 기술 및 연구 동향)

  • Ha, Seongmin;Kim, Daesup;Kwak, Cheol Hwan;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.33 no.4
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    • pp.343-351
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    • 2022
  • Lithium-ion batteries (LIBs) are considered promising energy storage devices with good performance such as high energy density, slow self-discharge rate, high rate charge capacity, and long battery life. However, the application of these LIBs in the high-energy density electric vehicle and large device industries poses a major safety problem. In order to solve this problem, developing a material having high thermal stability and intrinsic safety is the ultimate solution for improving the stability and electrochemical performance of LIBs. This review introduced a surface modification technology of a separator to overcome the stability problem of a commercial separator, and summarized and summarized the research trends using the modified separator for a lithium-ion battery. Based on this, the future prospects for the separator development by surface modification were discussed.

Sentiment Analysis and Issue Mining on All-Solid-State Battery Using Social Media Data (소셜미디어 분석을 통한 전고체 배터리 감성분석과 이슈 탐색)

  • Lee, Ji Yeon;Lee, Byeong-Hee
    • The Journal of the Korea Contents Association
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    • v.22 no.10
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    • pp.11-21
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    • 2022
  • All-solid-state batteries are one of the promising candidates for next-generation batteries and are drawing attention as a key component that will lead the future electric vehicle industry. This study analyzes 10,280 comments on Reddit, which is a global social media, in order to identify policy issues and public interest related to all-solid-state batteries from 2016 to 2021. Text mining such as frequency analysis, association rule analysis, and topic modeling, and sentiment analysis are applied to the collected global data to grasp global trends, compare them with the South Korean government's all-solid-state battery development strategy, and suggest policy directions for its national research and development. As a result, the overall sentiment toward all-solid-state battery issues was positive with 50.5% positive and 39.5% negative comments. In addition, as a result of analyzing detailed emotions, it was found that the public had trust and expectation for all-solid-state batteries. However, feelings of concern about unresolved problems coexisted. This study has an academic and practical contribution in that it presented a text mining analysis method for deriving key issues related to all-solid-state batteries, and a more comprehensive trend analysis by employing both a top-down approach based on government policy analysis and a bottom-up approach that analyzes public perception.

Development of Low-Cost, Double-Speed, High-Precision Operation Control System for Range Extender Engine (레인지 익스텐더 전기자동차 엔진용 저가형 2단속도 고정밀 운전제어시스템 개발)

  • Ham, Yun-Young;Lee, Jeong-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.529-535
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    • 2018
  • The range extender vehicle runs on a mechanism that allows the small power generation engine to start in the most efficient specific operating range to charge the battery and extend the mileage. In this study, we developed a step motor type intake air supply system that replaces existing throttle body system to develop a simple low cost control logic system. The system was applied to the existing base engine, and in order to improve the performance by increasing the amount of intake air, the effect of changing the length of the intake and exhaust manifold was experimentally examined. As a result, the Type B intake air control actuator operated by one step motor showed higher performance than the Type A in all the operation region, but the performance was lower than that of the base engine due to the increase of flow resistance. To improve this, it was confirmed that the engine performance was improved at both speeds of 2200rpm and 4300rpm when the 140mm adapter was installed in the intake manifold and when the newly designed 70mm exhaust manifold was applied. Through this process, high - precision operation control was realized by connecting the generator load to the optimized engine for the range extender electric vehicle. Experimental results showed that the speed change rate was within ${\pm}2.5%$ at 2200rpm in 1st stage and 4300rpm in 2nd stage and the speed follow-up result of 610 rpm/s was obtained when the speed was increased from 2200rpm to 4300rpm.

Bidirectional dc-to-dc Converter Employing Dual Inductor for Current Ripple Reduction (전류 리플 저감을 위한 듀얼 인덕터 방식의 양방향 dc-to-dc 컨버터)

  • Lee, Gi Yeong;Kang, Feel-soon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.4
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    • pp.531-537
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    • 2018
  • This paper propose a bidirectional dc-to-dc converter employing dual inductor for current ripple reduction. Conventional bidirectional dc-to-dc converter uses a single inductor for two different modes; boost and buck; therefore it is difficult to satisfy the optimized inductance value for each mode. To improve this problem, the proposed converter adds two switches, a diode, and one inductor. By proper switching of the additional switch, the proposed converter operates with a inductor in boost mode, but it works with dual inductor in buck mode. Hence in both modes the proposed bidirectional converter can be operated with optimized inductance values. Most of all the optimized inductance in buck mode can reduce the current ripple and its effective value(rms), which are directly related to the temperature increase resulted in short lifetime of battery. To verify the validity of the proposed approach, we first analyzes the operation of the proposed converter theoretically, and implement computer-aided simulations and experiments using a prototype.

Development of Fuel Cell/Battery Hybrid Vehicle (연료전지/배터리 하이브리드 차량 개발)

  • Son Yeong Jun;Park Gu Gon;Im Seong Dae;Eom Seok Gi;Yang Tae Hyeon;Yun Yeong Gi;Lee Won Yong;Kim Chang Su
    • 한국전기화학회:학술대회논문집
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    • 2005.07a
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    • pp.103-110
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    • 2005
  • Fuel cell systems are consisted of various parts, for example fuel cell stack, fuel supplier, electrical converters, controllers and so on. Each components of system should have appropriate specification for their applications as well as simplicity. Because thermal load can be managed simply by using fans without any water cooling system, the air-cooled PEMFC is widely used in sub kW and around 1kW systems. The performance of an air-cooled system is highly dependent on ambient temperature and humidity. In this paper, the air-cooled PEMFC systems are developed and investigated to study the operating characteristics in the aspect of the thermal and water coupled management by the control of the axial fans and compressors. Various experiments were also conducted to get the cell voltage distribution, the relative humidity of the reactant gas and the thermal management by axial cooling fans, which cannot be observed in single cell experiment. After then, as practical applications, portable fuel cell system and a hybrid electric cart were successfully integrated and operated by using this air-cooled stack.

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Quantitative Visualization of Outlet Flow of the Centrifugal Blower (원심 블로어 출구 유동의 정량적 가시화 연구)

  • Tu, Xin Cheng;Kim, Sung-Jun;Park, Seung Ha;Kim, Hyoung-Bum
    • Journal of the Korean Society of Visualization
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    • v.12 no.1
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    • pp.25-29
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    • 2014
  • The outlet flow of the centrifugal blower were quantitatively visualized using particle image velocimetry. Because the centrifugal blower is one of the key parts of electric vehicle battery cooling system, the quantitative information of centrifugal blower is necessary to design and optimize the cooling system. The effect of different inlet flow condition to the outlet flow was investigated in this study. Two different inlet ducts were used. One is the straight inlet and the other is a bended one. The results clearly showed the outlet flow asymmetry in both inlet ducts. When the blower has the bended inlet, the flow rate decreases due to the increase of the head loss.