• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.150-152
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• 2004

The battery charge/discharge process, the final step of the secondary battery production process, requires real-time precision controls for improving both lifetime and performance of the battery cell. In this paper, we present embedded system design for precision control of the secondary battery charge/discharge production process using low power embedded processor based on embedded linux. This system receive charge/discharge command from the main server through ethernet. Compared to existing charge/discharge control system, our design makes low cost and precision control system possible.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.241-242
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• 2006

In this work, the $LiFePO_4-LiCoO_2$ mixed cathode electrodes were prepared and their electrochemical performances were measured in different current density. The cell of $LiFePO_4-LiCoO_2$ observed two voltage plateau regions at 3.4 and 3.9V. The cell of $LiFePO_4-LiCoO_2$ (90:10 wt%) mixed cathode delivered a discharge capacity of ca. 139.8 mAh/g at a 0.2C rate. The capacity of the cell decreased with the current rate and a useful capacity of ca 85.7mAh/g was obtained at a 2C rate.

• Membrane Journal
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• v.5 no.3
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• pp.109-118
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• 1995

In this study, cell resistivity and membrane resistivity were measured in Fe-Cr redox-fiow battery system using commercial ion-exchange membranes. Cell resistivity and membrane resistivity at charging periods are higher than at discharging periods. And at the same membrane the resistivity were increased with increasing SOC. The resistivity of hydrocarbon type Seiemion CMV membrane was smaller than perfluoro type Nafion 117 and Nafion 551. The cell resistivity and membrne resistivity of CMV membrane at 0 % SOC was $12.864\Omega \textrm{cm}^2$ and $8.751\Omega \textrm{cm}^2$, respectively.

• Carbon letters
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• v.1 no.3_4
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• pp.170-177
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• 2001

Lithium intercalated carbon (LIC) are basically employed as an anode for currently commercialized lithium secondary batteries. However, there are still strong interests in modifying carbon surface of active materials of the anode because the amount of irreversible capacity, charge-discharge capacity and high rate capability are largely determined by the surface conditions of the carbon. In this study, the carbonaceous materials were coated with tin oxide and copper by fluidized-bed chemical vapor deposition (CVD) method and their coating effects on electrochemical characteristics were investigated. The electrode which coated with tin oxides gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. However, the cyclability was improved by coating with copper on the surface of the tin oxides coated carbonaceous materials, which plays an important role as an inactive matrix buffering volume changes. An impedance on passivation film was decreased as tin oxides contents and it resulted in the higher capacity.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.252-256
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• 2001

The rapid development of communication equipment and information processing technology has led to a constant improvement in cordless communication. Lithium ion batteries used in cellular phones and laptop computers, in particular, have been in the forefront of the above revolution. These batteries use high value added raw materials and have a high and stable energy output and are increasingly coming into common use. The development of the material for the negative terminal has led to an improvement in the quality and efficiency of the batteries, whereas a reduction in the cost of the battery by researching new materials for the positive anode has become a research theme by itself. These long life batteries, it is being increasingly realized, can have value added to them by recycling. Research is increasingly being done on recycling the aluminum case and the load casing for the negative diode. This paper aims to introduce the current situation of recycling of lithium ion batteries. 1. Introduction 2. Various types of batteries and the situation of their recycling and the facts regarding recycling. 3. Example of cobalt recycling from waste Lithium ion secondary cell. 3-1) Flow Chart of Lithium ion battery recycling 3-2) Materials that make a lithium ion secondary cell. 3-3) Coarse grinding of Lithium ion secondary cell, and stabilization of current discharge 3-4) Burning 3-5) Grinding 3-6) Magnetic Separation 3-7) Dry sieving 3-8) Dry Classifying 3-9) Content Ratio of recycled cobalt parts 3-10) Summary of the Line used for the recovery of Cobalt from waste Lithium ion battery. 4. Conclusion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3016-3021
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• 2011

While there is ample information on the investment plans about Korea's selected new growth businesses, it is hard to find any analysis on the valuation of the projects. In this paper, I intend to do a valuation for the three particular technologies, which are solar cell, automotive battery, and bio-pharmaceutical, based on compound option model so that the valuation can capture not only the expected net cash flow but also the value originated from the flexibility of the decision maker. In addition, the real option pricing theory is reviewed and its practical limitations are thoroughly investigated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.398-406
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• 2022

In order to increase the electrochemical performance of thermal battery anode, LIFT anode having the same weight but a larger lithium content in electrodes was fabricated by mixing lithium, iron and titanium. By applying these electrodes, a single cell and a thermal battery were prepared, and the effect of LIFT anode on electrochemical performance was evaluated. The LIFT-applied single cell presented a better cell performance than LIFe-applied single cell at 500℃ and 550℃. The discharge performance of LIFT-applied single cell, which included the operating time (787s), specific capacity (1,683 Asg^-1), and electrode utilization (80.7%), was improved collectively compared to the LIFe applied single cell (736s, 1,245 As g^-1, and 74.6%) at 500℃. As the discharge progressed, the internal resistance of LIFT anode decreased, because the lithium migration path was formed due to the presence of large titanium particles among iron particles. These results were analyzed in terms of the microstructure of electrode using SEM. Energy density of LIFT-applied single cell also increased by 10% to 142.1 Wh kg^-1 compared to that of LIFe-applied single cell (127.4 Wh kg^-1). In addition, the LIFT-applied single cell presented a stable discharge performance for 6,500s without a short circuit which could occur by molten lithium under an open circuit voltage condition with a high pressure (4 kgf cm^-2). As observed in the high temperature thermal battery performance tests, the voltage and specific capacity of LIFT-applied thermal battery are superior to those of LIFe-applied thermal batteries, indicating that the energy density of LIFT-applied thermal batteries should remarkably increase.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.363-368
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• 2007

Lithium-ion batteries providing high gravimetric energy density are rapidly replacing Ni-Cd and Ni-H2 in aerospace applications. The main advantage is the weight reduction of the battery system. Weight is a major concern in aerospace applications. Also, lithium-ion offer low thermal dissipation, high energy efficiency, and low cell cost. The Onboard battery module for KSLV-I(Korea Space Launch Vehicle) contains 80 Sony US18650 cells configured as 10 strings in parallel, with each string containing 8 series connected cells. This allows to meet voltage and capacity requirements specified for the mission. In this paper design description and specifications of lithium-ion battery developed are presented. Qualification test flow is also shown to make sure the performance in the predicted space environment. Electrical performance was simulated by dedicated program, and verified with electronic load. Lastly, the capacity was proven on real equipment load assembly.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.17-22
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• 2014

The design of a fuel cells stack is important to get optimal output power. This study focuses on the evaluation of fuel cell system for unmaned aerial vehicles (UAVs). Low temperature proton exchange membrane (LTPEM) fuel cells are the most promising energy source for the robot applications because of their unique advantages such as high energy density, cold startup, and quick response during operation. In this paper, a 600 W open cathode LTPEM fuel cell was tested to evaluate the performance and to determine optimal operating conditions. The open cathode design reduces the overall size of the system to meet the requirement for robotic application. The cruise power requirement of 600 W was supported entirely by the fuel cell while the additional power requirements during takeoff was extended using a battery. A peak of power of 900 W is possible for 10 mins with a lithium polymer (LiPo) battery. The system was evaluated under various load cycles as well as start-stop cycles. The system response from no load to full load meets the robot platform requirement. The total weigh of the stack was 2 kg, while the overall system, including the fuel processing system and battery, was 4 kg.