• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.413-414
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• 2012

본 논문에서는 C-rate, 온도, SOC (State-of-Charge, 잔존용량)를 고려하여 NiMH 배터리를 모델링하였고, 시뮬레이션 결과를 배터리 실험 결과와 비교하였다. 제안한 배터리 모델은 1차 테브난 등가회로를 기반으로 구성하였으며 Matlab/Simulink 환경에서 구현하였다. 모델을 구현하기 위한 실험으로는 정전류, 펄스전류 실험을 하여 가변온도와 다양한 C-rate에서 변하는 파라미터를 도출하였고, 도출한 파라미터는 룩업 테이블을 이용하여 배터리 모델에 적용하였다. 제안된 배터리 모델을 짧은 시간동안 불규칙하게 변하는 전류 패턴에 대한 시뮬레이션과 실험 파형을 통하여 배터리 모델의 성능을 검증하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.3
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• pp.159-170
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• 1999

Recently Ni/MH secondary battery have been studied very extensively because of containing no pollutants as well as superior performance. However comparing to widely studying high capacity of hydrogen storage alloys electrode, the capacity of Ni electrode is inferior. Using for high capacity Ni/MH battery as a anodic materials, the study about high capacity Ni electrode is necessary. To making high capacity Ni electrode, active materials were impregnated in various polarization impregnation conditions. Plaque, milling for 6hr and sintered at $800^{\circ}C$, indicated porosity over 80%, and porosity were increased with proper condition electrochemical etching treatment. Proper impregnation condition was 40~80mA/cm, polarizing time was 5~10min.

• Journal of Powder Materials
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• v.25 no.3
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• pp.213-219
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• 2018

We report a method for preparing rare earth oxides ($Re_xO_y$) from the recycling process for spent Ni-metal hydride (Ni-MH) batteries. This process first involves a leaching of spent Ni-MH powders with sulfuric acid at $90^{\circ}C$, resulting in rare earth precipitates (i.e., $NaRE(SO_4)_2{\cdot}H_2O$, RE = La, Ce, Nd), which are converted into rare earth oxides via two different approaches: i) simple heat treatment in air, and ii) metathesis reaction with NaOH at $70^{\circ}C$. Not only the morphological features but also the crystallographic structures of all products are systematically investigated using field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD); their thermal behaviors are also analyzed. In particular, XRD results show that some of the rare earth precipitates are converted into oxide form (such as $La_2O_3$, $Ce_2O_3$, and $Nd_2O_3$) with heat treatment at $1200^{\circ}C$; however, secondary peaks are also observed. On the other hand, rare earth oxides, RExOy can be successfully obtained after metathesis of rare earth precipitates, followed by heat treatment at $1000^{\circ}C$ in air, along with a change of crystallographic structures, i.e., $NaRE(SO_4)_2{\cdot}H_2O{\rightarrow}RE(OH)_3{\rightarrow}RE_xO_y$.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.1
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• pp.39-44
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• 1996

The discharge capacity of V-Ti-Ni(V-rich) metal hydride electrode during the charge-discharge cycling was investigated in KOH electrolyte. All electrodes were degraded within 25 cycles. To investigate the cause of the degradation phenomena impedance measurements were performed by using E.I.S(electrochemical impedance spectroscopy). The surfaces of the degraded electrodes were examined by Auger electron spectroscopy (AES). It was observed that all electrodes were covered with oxygen from the surface to the bulk, titanium was enriched near surface, and vanadium was dissolved from the surface to the bulk.

• Transactions of the Korean hydrogen and new energy society
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• v.8 no.2
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• pp.51-56
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• 1997

The Zr-based Laves phase, $ZrV_2$ hydrogen storage alloy is not suited for the electrode of Ni-MH battery, because the binding strength of that with hydrogen is too strong although the storage capacity is high. For an application to electrode a part of V in alloys is substituted with Ni to make weaken the binding strength. The electrochemical and thermodynamic properties of Zr-V-Ni system alloys are investigated from the equilibrium potential and studied the possibility for the application to the rechargeable battery electrode.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.518-519
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• 2011

오늘날 스마트 그리드, 하이브리드 자동차 등에 관한 연구가 활발히 진행됨에 따라 에너지 저장장치에 관한 관심이 높아지고 있다. 그 중 연구가 활발히 진행되어지고 있는 배터리인 Ni-Mh와 Li-polymer의 모델링한 연구에 대하여 시뮬레이션을 하였고 모델링 방법과 성능에 대하여 비교하여 보았다.

• KIPE Magazine
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• v.11 no.3
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• pp.15-19
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• 2006

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.6
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• pp.505-511
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• 2009

The hydriding and electrochemical characteristics of Zr-based $AB_2$ alloy produced by gas atomization have been extensively examined. For the particle morphology of the as-cast and gas-atomized powders, it can be seen that the mechanically crushed powders are irregular, while the atomized powder particles are spherical. The increase of jet pressure of gas atomization process results in the decrease of hydrogen storage capacity and the slope of plateau pressure significantly increases. TEM and EDS studies showed the increase of jet pressure in the atomization process accelerated the phase separation within grain of the gas-atomized alloy, which brought about a poor hydrogenation property. However, the gas-atomized $AB_2$ alloy powders produced by jet pressure of 50 bar kept up the reversible $H_2$ storage capacity and discharge capacity similar to the mechanically crushed particles. In addition, the electrode of gas-atomized Zr-based $AB_2$ alloy of 50 bar showed improved cyclic stability over that of the cast and crushed particulate, which is attributed to the restriction of crack propagation by grain boundary and dislocation with ch/discharging cycling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.3
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• pp.227-234
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• 2014

Fuel consumption rates of electric vehicles strongly depend on their battery performance. Because the battery performance is sensitive to the operating temperature, temperature management of the battery ensures its performance and durability. In particular, the temperature distribution among modules in the battery pack affects the cooling characteristics. This study focuses on the thermal modeling of a battery pack to observe the temperature distribution among the modules. The battery model is a prismatic model of 10 NiMH battery modules. The thermal model of the battery consists of heat generation, convective heat transfer through the channel and conduction heat transfer among modules. The heat generation is calculated by the electric resistance heat during the charge/discharge state. The model is used to determine a strategy for proper thermal management in Electric vehicles.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.4
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• pp.225-232
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• 1999

The $Mg_2Ni$ hydrogen storage alloys which have much higher theoretical discharge capacity than $AB_5$ and $AB_2$ type alloys were synthesized by mechanical alloying with some additives and subjected to the electrochemical measurements. Two different processes were employed to the synthesis of $Mg_2Ni$ alloys with using the high energy ball mill SPEX 8000. One was only ball milling, 12 hrs, the Mg and Ni powders for 12 hrs with additives such as $AB_5$, Ni, Co and Cu powders. In the other process the Mg and Ni powders were ball milled for 1 hr first and then heat treated at $300{\sim}400^{\circ}C$ for 1 hr to get $Mg_2Ni$ alloy, and finally the $Mg_2Ni$ alloy powders were ball milled with the additives for 12 hrs. The alloy powders prepared were compacted at room temperature under $7.64tons/cm^2$ into disk type electrodes for the electrochemical measurements. The experimntal results showed that the electrodes prepared with the heat treated alloy powders had a higher discharge capacities than those without heat treatment. The addition of Ni caused an increase of the discharge capacity and the addition of Co improved the cycling characteristics. The electrode prepared by ball milling of $Mg_2Ni$ and 10wt% Ni powders has showed the highest discharge capacity, 546mAh/g.alloy, which was 55% of the theoretical capacity.