• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.1-12
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• 2021

As increasing the international community's awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries' size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.357-363
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• 2021

Eco-friendly hybrid railroad propulsion system with fuel-cell and battery was suggested to reduce carbon dioxide gas and replace retired diesel railroads. Lithium-ion battery with high energy/power density and long lifetime is selected as the energy source at the battery side due to its excellent performance. However, the performance of lithium-ion batteries was affected by temperature, current rate, and operating condition. Temperature is known to be the most influential factor in changing battery parameters. In addition, appropriate thermal management is required to ensure the safe and effective operation of lithium-ion battery. Electro-thermal coupled model with varying parameter depends on temperature, and state-of-charge (SOC) is suggested to estimate battery temperature. The electric-thermal coupled model contains diffusion current using parameter identification by adaptive control algorithm when considering thermal diffusion effect. An experiment under forced convection was conducted using cylindrical cell and 18 parallel-connected battery module to demonstrate the method.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.408-414
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• 2018

Given that lithium-ion batteries are expected to be used as power sources for electric and hybrid vehicles, thermodynamics experimentation and prediction based on experimental data were performed. Thermal, electrochemical, and electrochemical/electrical-thermal models were used for accurate battery modeling. Various applications of different battery packs were demonstrated, and thermal analysis was performed using the same experimental conditions for square and rectangular battery packs. Accurate thermal analysis for a single cell should be prioritized to determine the thermal behavior of the battery pack. The energy balance equation, which contains heat generation and heat transfer factors, defines the thermal behavior of the battery pack. By comparing battery packs of different shapes tested under the same condition, this study revealed that the rectangular battery pack is superior to the square battery pack in terms of the maximum temperature of inner cells and temperature variation between cells.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.423-424
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• 2016

Recently, the mass production of Energy storage system (ESS) is actively perform around world. Energy storage system is a technique that stores power to energy storage device to supply energy into grid and load at peak-load. Therefore, the efficient energy management is available by using ESS system. The life of Lithium-ion battery is varied corresponding to the power usage, especially selected depth of discharge (DOD). The lifetime of battery is the one of the most issue of the ESS system because of its stability and reliability. Therefore, lifetime management of battery and power converter of ESS module is required. In this paper, the battery lifetime management method estimating residual power and lifetime of lithium ion battery of ESS system is proposed. Also, total avenue prediction of ESS system is simulated considering the total lifetime of battery.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1363-1368
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• 2007

In order to utilize renewal energy such as solar power and wind power, high performance battery charge-discharge controller is essentially needed. In this paper, a PIC microprocessor-based battery charge-discharge controller for solar power system is designed and implemented. The PIC16C711 microprocessor and CCS-C compiler are used to realize stable and accurate operation of the battery controller. The proposed controller is designed to utilize the charged battery power during daytime to provide convenience to user. Current control function is included in proposed controller to cope with various type of new material energy system coming in the near future.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.787-798
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• 2013

This paper proposes a special power circuit topology and its corresponding control strategy for an energy recovery power accumulator battery pack testing system (PABPTS), which is particularly used in electric vehicles. Firstly, operation principle and related parameter design for the system are illustrated. Secondly, control strategy of the composite power converter for PABPTS is analyzed in detail. The improved scheme includes a high accuracy charge and discharge current closed loop. active power reference for the grid-side inverter is provided by the result of multiplication between battery pack terminal voltage and test current. Simulation and experimental results demonstrate that the proposed scheme could not only satisfy the requirements for PABPTS with wide-range current test, but also could recover the discharging energy to the power grid with high efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.570-571
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• 2021

The research on waste power batteries in China in the past ten years reveals that the power battery recycling industry is enormous but marred with several challenges. A study of China's current power battery closed-loop supply chain revealed some issues in the power battery recycling industry, such as imperfect supply chain, small recycling scale, asymmetric information, and imperfect profit distribution mechanism. This paper uses the theory of corporate social responsibility and consumer choice to propose a closed-loop network of power batteries based on block chain technology and analyzes the existing closed-loop supply chain of power batteries. Consequently, this study provides a new idea for developing the power battery closed-loop supply chain by proposing the closed-loop network of power batteries based on blockchain technology

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.95.1-95.1
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• 2005

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.6
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• pp.535-542
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• 2017

This paper proposes a simple 3-level interleaved charger-discharger for the uninterruptible power supply (UPS) with various combinations of battery cells. The proposed converter not only improves charging and discharging efficiency, but also reduces the physical volume and the cost. Furthermore, the converter also offers the capability of the neutral point voltage, so that more stable operation can be obtained. In addition, the proposed converter significantly reduces the ripple current of the battery inductor, thereby providing an expected life extension of the battery. Experimental results for a 300kVA UPS prototype verify the validity of the proposed converter. The proposed charger-discharger is suitable for UPSs and energy storage systems (ESSs) with wide input battery voltage ranges.

• Korean Journal of Chemical Engineering
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• v.36 no.1
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• pp.12-20
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• 2019

An energy storage system consisting of a battery and a power-to-methanol (PtM) unit was investigated to develop an energy storage system for renewable energy systems. A nonlinear programming model was established to optimize the energy storage system. The optimal installation capacities of the battery and power-to-methanol units were determined to minimize the cost of the energy system. The cost from a renewable energy system was assessed for four configurations, with or without energy storage units, of the battery and the power-to-methanol unit. The proposed model was applied to the modified electricity supply and demand based on published data. The results show that value-adding units, such as PtM, need be included to build a stable renewable energy system. This work will significantly contribute to the advancement of electricity supply and demand management and to the establishment of a nationwide policy for renewable energy storage.