• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.65-70
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• 2010

A small unmanned aerial vehicle(UAV), which uses a propulsion system consisting of electric motor and battery, weighs less than 8 kg, capable of hand launch. Because it is easy to operate and able to transmit image information in real time, the use of small UAV has been increasing. However, very few analysis methods or analysis results on flight performance of the small UAV have been known so far. In this paper, the performance analysis methods of a small UAV, which is manufactured to study an electric powered UAV, are suggested and their results are achieved. Aerodynamic data of the vehicle are obtained by making use of gliding performance from actual flight test, and required thrust and required power by flight speed are predicted. In addition, the methods to predict range and endurance in case of using battery as power source are suggested and their results are achieved.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.3
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• pp.227-234
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• 2020

This paper presents the methods for the modeling and parameter optimization of the electric vehicle battery. The state variables of the battery are defined, and the test methods for battery parameters are presented. The state-space equation, which consists of four state variables, and the output equation, which is a combination of to-be-determined parameters, are shown. The parameter optimization method is the key point of this study. The least square of the modeling error can be used as an initial value of the multivariable function. It is equivalent to find the minimum value of the error function to obtain optimal parameters from multivariable function. The SIMULINK model is presented, and the 10-hour full operational range test results are shown to verify the performance of the model. The modeling error for 25 degrees is approximately 1% for full operational ranges. The comments to enhance modeling accuracy are shown in the conclusion.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.759-764
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• 2021

Because sensitive and private information should be exchanged between electric vehicles and a V2G service provider, reliable communication channel is essential to operate Vehicle-to-Grid (V2G) system which considers battery of electric vehicles as a factor of smart grid. The block chain is a platform for cryptocurrency transaction and fully distributed database system running by only equivalent node in the network without help of any central management or 3^rd party. In this paper, the structure and operation method of the blockchain are investigated, and the application of the blockchain for the V2G system was also explained and analyzed.

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.

• Journal of Power Electronics
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• v.11 no.4
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• pp.471-478
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• 2011

This paper addresses the establishment of a kVA-range plug-in hybrid electrical vehicle (PHEV) integration test platform and associated issues. Advancements in battery and power electronic technology, hybrid vehicles are becoming increasingly dependent on the electrical energy provided by the batteries. Minimal or no support by the internal combustion engine may result in the vehicle being occasionally unable to recharge the batteries during highly dynamic driving that occurs in urban areas. The inability to sustain its own energy source creates a situation where the vehicle must connect to the electrical grid in order to recharge its batteries. The effects of a large penetration of electric vehicles connected into the grid are still relatively unknown. This paper presents a novel methodology that will be utilized to study the effects of PHEV charging at the sub-transmission level. The proposed test platform utilizes the power hardware-in-the-loop (PHIL) concept in conjunction with high-fidelity PHEV energy system simulation models. The battery, in particular, is simulated utilizing a real-time digital simulator ($RTDS^{TM}$) which generates appropriate control commands to a power electronics-based voltage amplifier that interfaces via a LC-LC-type filter to a power grid. In addition, the PHEV impact is evaluated via another power electronic converter controlled through $dSPACE^{TM}$, a rapid control systems prototyping software.

• Journal of Hydrogen and New Energy
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• v.29 no.6
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• pp.661-667
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• 2018

Electric vehicles are taken a long time to charge and are restricted driving where charging infrastructure was not sufficiently constructed. The vehicle developed to solve these problems is a plug-in hybrid vehicle. It is possible to drive a certain distance by using electric motor and when the battery runs out, it operate the engine. Plug-in hybrid vehicle have a complicated structure and a lot of parts comparing a general vehicle because the electric parts and the internal combustion engine are installed together. Therefore, as the aging (mileage) of the plug-in hybrid vehicle, the influence which change of fuel consumption is expected to be larger than a general vehicle, but an experimental data are lacking. In this paper, we cumulate a mileage of the plug-in hybrid vehicle about 15,000 km and measured the fuel economy when the cumulated distance reached within 160 km, 6,500 km, 15,000 km respectively, by using domestic public test method. For measuring fuel economy of the vehicle, CD mode (driving distance on a single charge) which use only motor and the CS mode which operate motor and combustion engine were measured respectively. As a result, the fuel economy slightly increased at cumulated mileage of 6,500 km compared to the 160 km and the fuel economy of 15,000 km was similar to 160 km.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.3
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• pp.13-23
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• 2022

Demand and interest in electric vehicles are increasing rapidly due to environmental issues. Improving the performance of electric vehicles requires the development of automotive batteries and battery joining technologies. Aluminum alloys are the most widely used metals in the electric vehicle industry, and aluminum bonding is used in all processes comprising automotive batteries. Therefore, in this paper, based on the characteristics of aluminum and aluminum alloys and knowledge of various aluminum joining technologies, the main and the next generation bonding technologies used in automotive battery are reviewed. It also explains the structure of automotive secondary battery cells and the integration order of 'cell-module-pack' where joining is used in the process, also various environmental conditions that must be considered when joining.

• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.15-19
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• 2013

This paper is to analyze and study the cause of fire examples produced because of short phenomenon by electric connecting damage and contacting engine over-heating with combustible materials in engine room of vehicle. In the first example, it knew the fact that the fire produced by contacting with body of vehicle because of loosed of bracket bolt for wire fixing that installed on the transmission case the battery power cable supply the power from battery of engine room to starting motor. In the second example, it certified the fire by short phenomenon because of insulation tape melting wound wiring lined from battery to starting motor. In the third example, it sought for fire's cause that melting phenomenon the wire coating by overheated engine as the wire disconnected with connector by the vibration. Therefore, the fire of system including engine electric made in the danger the people in the car by failure of engine and other system. And than, the car's driver must manage and examine a vehicle conscientiously.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.333-340
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• 2022

Recently, the use of large-capacity secondary batteries for electric vehicles is rapidly increasing, and accordingly, the demand for technologies and equipment for battery reliability evaluation is increasing significantly. The existing short circuit test equipment for evaluating the stability of the existing secondary battery consists of relays, MCs, and switches, so when a large current is energized during a short circuit, contact fusion failures occur frequently, resulting in high equipment maintenance and repair costs. There was a disadvantage that repeated testing was impossible. In this paper, we developed an electronic short circuit test device that realizes stable switching operation when a large-capacity power semiconductor switch is energized with a large current, and applied smart ICT technology to this electronic short circuit stability test system to achieve high speed and high precision through communication with the master. It is expected that the inspection history management system based on data measurement, database format and user interface will be utilized as essential inspection process equipment.

• Journal of the Korean Electrochemical Society
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• v.2 no.4
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• pp.218-220
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• 1999

The performance of the Electric Vehicle and Hybrid Electric Vehicle depends on that of the battery pack composed of series connected batteries. And thermal property is one of the main factors which decide the performance of the battery pack. So heat generation rate from the battery under the various driving mode must be measured as precise as possible because thermal characteristics of the battery affect the driving performance and battery pack's life cycle. Besides, to design and develop the battery thermal management system for the EV and HEV, the measurements of the thermal properties of the batteries are needed. However, the established calorimeter is not adequate to test an EV's battery because its cavity is too small to accommodate the EV's battery. Therefore we developed the calorimeter to test the thermal property of the EV's battery. Its cavity size is 120mm long, 75mm wide and 200mm high. The calorimeter is calibrated by the dummy cell which generates the heat rate from zero to 200W. The measuring accuracy of the calorimeter is within $2\%$ and its voltage stability is 2.5mV in the constant temperature bath.