• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.31-48
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• 2024

The domestic automotive industry must consider a strategic shift from traditional automotive component manufacturing to align with future trends such as connectivity, autonomous driving, sharing, and electrification. This research conducted topic modeling on R&D projects in the future automotive sector funded by the Ministry of Trade, Industry, and Energy from 2013 to 2021. We found that topics such as sensors, communication, driver assistance technology, and battery and power technology remained consistently prominent throughout the entire period. Conversely, topics like high-strength lightweight chassis were observed only in the first period, while topics like AI, big data, and hydrogen fuel cells gained increasing importance in the second and third periods. Furthermore, this research analyzed the areas of concentrated investment for each period based on topic-specific government investment amounts and investment growth rates.

• Transactions of Materials Processing
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• v.33 no.2
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• pp.103-111
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• 2024

With the increasing global interest in carbon neutrality, the automotive industry is also transitioning to the production of eco-friendly cars, specifically electric vehicles. In order to achieve comparable driving distances to internal combustion engine vehicles, the application of high-capacity battery packs has led to an increase in vehicle weight. To achieve light-weighting and durability requirements of automotive components simultaneously, there is a demand for research on the application of Ultra-High Strength Steel (UHSS). However, when manufacturing chassis components using UHSS, there are challenges related to fracture defects due to lower elongation compared to regular steel sheets, as well as spring-back issues caused by high tensile strength. In this study, a simulated specimen that is not affected by the property changes of four materials was designed to improve formability of the rear cross member, which is the most challenging automotive chassis component. The influence and correlation of material-specific variables were analyzed through finite element analysis (FEA) for each material with tensile strength of 440, 590, 780, and 980 MPa grades, resulting in the development of a predictive equation. To validate the equation, the simulated specimens of 980 MPa grade were produced from the test molds. Then the reliability of the FEA and predictive equation was verified with measured specimen data using a 3D scanner. The results of this study can be proposed to improve the formability of UHSS chassis components in future researches.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.445-450
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• 2024

The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li₂O/B₂O₃ in borate glass comprising Li₂O-B₂O₃-Al₂O₃ system. The glass transition temperature is decreasing as increasing the amount of Li₂O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.35-43
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• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.289-298
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• 2014

Recently, the traditional paradigm in railroad technology is changing as more efficient and cost-effective electric vehicle (EV) technologies have emerged. The original concept of PRT (Personal Rapid Transit) proposed in the past has come to be regarded as unrealistic, but its feasibility is improving through the utilization of an EV platform. In particular, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. However, based on the inductive power transfer (IPT) technology, the fast charging of supercapacitors with high energy density can contribute to overcoming this technical challenge and promote the transition to electric-powered ground transportation by improving the appearance of cities. This study discusses the development process of a power supply system for PRT, including concept design, numerical analysis, and device manufacturing, along with performance predictions and evaluations. In terms of results, the system was found to meet the performance requirements for power supply modules on a test-bed.

• 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.

• Resources Recycling
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• v.28 no.6
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• pp.79-86
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• 2019

Recently, the use of lithium ion battery(LIB) has increased. As a result, the price of lithium and the amount spent lithium on ion battery has increased. For this reason, research on recycling lithium in waste LIBs has been conducted1). In this study, the effect of roasting for the selective lithium leaching from the spent LIBs is studied. Chemical transformation is required for selective lithium leaching in NCM LiNi_xCo_yMn_zO₂) of the spent LIBs. The carbon in the waste EV cell powder reacts with the oxygen of the oxide at high temperature. After roasting at 550 ~ 850 ℃ in the Air/N₂ atmosphere, the chemical transformation is analysed by XRD. The heat treated powders are leached at a ratio of 1:10 in D.I water for ICP analysis. As a result of XRD analysis, Li₂CO₃ peak is observed at 700 ℃. After the heat treatment at 850 ℃, a peak of Li₂O was confirmed because Li₂CO₃ is decomposed into Li₂O and CO₂ over 723 ℃. The produced Li₂O reacted with Al at high temperature to form LiAlO₂, which does not leach in D.I water, leading to a decrease in lithium leaching ratio. As a result of lithium leaching in water after heat treatment, lithium leaching ratio was the highest after heat treatment at 700 ℃. After the solid-liquid separation, over 45 % of lithium leaching was confirmed by ICP analysis. After evaporation of the leached solution, peak of Li₂CO₃ was detected by XRD.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.86-92
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• 2022

Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.543-548
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• 2015

Si/C/CNF composites as anode materials for lithium-ion batteries were examined to improve the capacity and cycle performance. Si/C/CNF composites were prepared by the fabrication process including the synthesis and magnesiothermic reduction of SBA-15 to obtain Si/MgO by ball milling and the carbonization of phenol resin with CNF and HCl etching. Prepared Si/C/CNF composites were then analysed by BET, XRD, FE-SEM and TGA. Among SBA-15 samples synthesized at reaction temperatures between 50 and $70^{\circ}C$, the SBA-15 at $60^{\circ}C$ showed the largest specific surface area. Also the electrochemical performances of Si/C/CNF composites as an anode electrode were investigated by constant current charge/discharge test, cyclic voltammetry and impedance tests in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC : DMC : EMC = 1 : 1 : 1 vol%). The coin cell using Si/C/CNF composites (Si : CNF = 97 : 3 in weight) showed better capacity (1,947 mAh/g) than that of other composition coin cells. The capacity retention ratio decreased from 84% (Si : CNF = 97 : 3 in weight) to 77% (Si : CNF = 89 : 11 in weight). It was found that the Si/C/CNF composite electrode shows an improved cycling performance and electric conductivity.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.257-263
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• 2015

The purpose of this study was to survey the elderly patients through Basic information, Problems Wheelchair, Wheelchair Satisfaction, Usage and Requirements. The meaning of purpose is identify the problems and difficulties of wheelchair use in geriatric patients and an alternative for the correct use of wheelchairs elderly patients. The study investigated through questionnaires. That used questionnaires to modified to Gu Hyeon-Mo questionnaire (2005) and Quebec User Evaluation of Satisfaction with assistive Technology 2.0. 120 of 150 questionnaires were collected and one of them is excluded. Analysis results suggest the following. It was often feel joint pain results from physical damage. In addition when you use a wheelchair it was often feel discomfort in lower back and pelvis. And it feels uncomfortable when moving the tilt. Wheelchair satisfaction of the participants responded to the most 'Normal'. Results of the wheelchair operation ability is as follows. In the case of manual wheelchairs was feeling the difficulty to cross the threshold, Wheel lying, Stairs usage. Also In the case of an electric wheelchair was feeling the difficulty to use Tilt and Decline, Separate from the motor, and Replacement battery. In conclusion, To reduce of back pain and hip joints of elderly patients need to modify design and appearance of the wheelchair. In a later study will find to reduce discomfort and to improve satisfaction of the elderly who use wheelchairs. It will have to periodically examine the usage and satisfaction with them.