• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.26-32
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• 2020

In this study, the side reactions that greatly affect the coulombic efficiency of a zinc-air secondary battery are quantitatively analyzed on the basis of the charging-discharging characteristics, open circuit self-discharge characteristics, and a series of calculations. In particular, the charge amounts consumed by water electrolysis and self-discharge during charging process are separately determined so that the charging efficiency (the amount of charge used in actual charging with respect to the applied charge amount) can be estimated, which would enable systematic understanding of the cause of coulombic efficiency degradation. Using two cells with different charging overvoltages, the validity of the proposed method can be assessed.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.281-286
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• 2022

In this study, design of an intuitive internal resistance diagnostic device is to diagnose the residual capacity and aging of the battery regardless of the model and the internal protocol of the waste battery through the method of measuring the internal resistance of a waste battery. In this paper, charging and discharging were continuously performed with 2A charging and 5A discharging in order to secure data on impedance changes that may occur in the charging and discharging process of various methods. As a result of the final experiment, it was confirmed that the impedance change occurred during charging and discharging, and the amount of change increased as the charging/discharging C-rate increased. In addition, it was confirmed that the waste battery aged or abnormal cell had a large change in the impedance value.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.313-316
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• 2022

In this paper, we implement a system that detects abnormalities in the charging data transmitted from the charger during the charging process of electric vehicles and controls them remotely. Using classification algorithms such as logistic regression, KNN, SVM, and decision trees, to do this, an analysis model is created that judges the data received from the charger as normal and abnormal. In addition, a model is created to determine the cause of the abnormality using the existing charging data based on the analysis of the type of charger abnormality. Finally, it is solved using unsupervised learning method to find new patterns of abnormal data.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3315-3325
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• 1994

To study the variation of charging efficiency in the engine intake, the method to change the natural frequency of intake system using the intake control valve was studied and it has been used in actual engine to increase the intake air. In this paper, the method of characteristics was used to analyze the non-steady state and compared with the experimental data of the 6-cylinder diesel engine showing the effectiveness of the method theoretically.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.16-19
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• 2018

This paper presents analytical and numerical simulation approaches on charging characteristics of no-insulation (NI) REBCO pancake coil by using the equivalent circuit model to estimate magnetic performance response in the coil. The analytical methods provide closed form or definite solution in the form of complete mathematical expressions but they are hard to solve the complex problems. Numerical methods have become popular with the development of the computing capabilities to solve the problems which are impossible or very hard to solve analytically. First of all, the equivalent circuit model are proposed to develop the simulation code for both analytical and numerical method. The charging test was performed under critical current to obtain magnetic field induced and terminal voltage through the radial as well as spiral current paths within the coil. To verify the validity of both proposed methods, the simulation results were compared and discussed with the experimental results.

• Journal of Power Electronics
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• v.19 no.3
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• pp.691-701
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• 2019

To solve the problems in the contact charging of inspection robots, a wireless charging system for inspection robots and a control strategy are introduced in this paper. Circuit models of a wireless power system with a compound compensation circuit and a three-phase Class-D resonant inverter are set up based on circuit theory. An output voltage control method based on the equal spread regulation of the phase difference between adjacent phases and the parameter correction method in the primary compound compensation circuit are proposed. The dynamic characteristics of the key parameters varying with the secondary coil position are obtained to further investigate the adaptive location scheme during the access and exit processes of moving robots. Combining the output voltage control method and the adaptive location scheme, a transition control strategy for the standby and operation modes of the wireless charging systems for inspection robots is put forward to realize the system characteristics including the low standby power in the standby mode and the high receiving power in the operation mode. Finally, experiments are designed and conducted to verify the correctness of the theoretical research.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.183-185
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• 2011

A multiple charging method for a wireless power transfer system (WPTS) in the near-field region is proposed. We analyzed the frequency characteristics of multiple receivers in the near-field region. The results suggested that the time division WPTS can achieve efficient and equal power transmission at multiple receivers. We conclude that this system has an advantage for charging multiple receivers.

• Journal of the Korean institute of surface engineering
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• v.45 no.3
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• pp.130-135
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• 2012

Hydrogen charging was electrochemically conducted at high strength DP steels and TRIP steel with varying charging time. The penetration depths and the mechanical properties with charging conditions were investigated through the distribution of micro-hardness and the microstructural observation of the subsurface zone. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of subsurface zone in addition to the microscope investigation. It was shown that the hydrogen amounts decreased in DP steels and TRIP steel with increasing hydrogen charging time. As shown by micro-Vickers hardness test and small punch test results, micro-Vickers hardness and SP energy for DP steels and TRIP steel decreased with increasing hydrogen charging time, for constant value of charging current density. SEM investigation results for the hydrogen contained samples showed that the major fracture behavior was brittle fracture which results in dimples on fractured surface and the size of dimples were decreased with increasing hydrogen charging time. These results indicate that hydrogen embrittlement is the major cause for the fracture of high strength steels and also micro-Vickers hardness test and small punch test is a valuable test method for hydrogen embrittlement of high strength sheet steels.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.73-74
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• 2010

In this paper, Around the world for electric vehicles are gaining attention and market trends to domestic and foreign policy. Current charging method developed techniques are discussed and is proposed for domestic situations and charging ways. The electric vehicle is emerging as a result of the energy efficiency issue, the combined battery and capacitor switching is proposed to use to offset the disadvantages of each method to improve the energy efficiency offers.

• Macromolecular Research
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• v.8 no.1
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• pp.6-11
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• 2000

In this study, we examined the charging behavior of chopped carbon fibers during electro-flocking process, which is one of the key processes of the novel technique for fabricating conductive polymer composite films. Short carbon fibers (CF) during electroflocking were electrically charged by the combined effect of contact charging, corona charging and tribocharging. The specific charge built on CF surface was measured by using Faraday cup method. Specific charge increased not only with increasing electric field strength and potential impressed to mesh electrode as expected from theoretical considerations in literature, but with decreasing mesh opening size due to the improved contact charging condition. However, CF length was found unexpectedly to influence the amount of CF specific charge due to the agglomerated nature of CF flocks leading to the change in charging conditions.