• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1509-1511
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• 2005

군수용 이차전지는 납축전지, 니켈-카드뮴전지 등이 주로 응용되고 있다. 군수용 전지의 경우 민수용에 비해 사용온도범위가 넓고, 진동, 충격 등의 환경시험규격이 까다로우며, 높은 신뢰성이 보장되어야만 한다. 또한 최근 환경문제의 부각으로 니켈-카드뮴전지는 차츰 설자리를 잃어가고 있으며, 납축전지의 경우 오염물질의 배출뿐만 아니라 저온성능이 떨어지는 단점을 가지고 있다. 이의 일환으로 최근 선진외국에서는 이를 대체하기 위한 연료전지, 리튬-이온, 리튬-폴리머, 니켈-수소전지 등의 개발 및 적용이 확대되고 있는 실정이다. 하지만 연료전지의 경우 상용화가 아직 이루어지지 않고 있으며, 리튬계열 배터리의 경우 이상상태에서 폭발하는 특성을 갖고 있어 많은 문제점을 내포하고 있다. 본 논문에서는 군용 니켈-수소전지를 대상으로 특성을 알아보고 배터리의 합리적 운용을 돕기 위한 배터리관리시스템에 대해 살펴보고자 한다.

• Transactions of the Korean hydrogen and new energy society
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• v.9 no.4
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• pp.135-141
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• 1998

The effects of heat-treatment on discharge characteristics of $TiFe_{1-x}Ni_x$ alloy were investigated. The content of Ni in alloy was varied from x = 0.1 to 0.6 by each 0.1 increment. Discharge capacity change of each alloy with C/D cycles was measured. With increasing Ni-content initial discharge capacity was increased. but at x = 0.6 it was deceased again. With increasing C/D cycles discharge capacity was rapidly decreased in the alloy of high Ni-content. In order to investigate the effects of heat-treatment on cycle life, $TiFe_{0.5}Ni_{0.5}$ alloy having maximum initial discharge capacity was heat-treated at various temperatures in the range of $700{\sim}900^{\circ}C$ and tested. The loss of initial discharge capacity was appeared at all temperatures. but cycle characteristics of the alloy was improved. The electrodes heat-treated for 1 hour in the range of $700{\sim}850^{\circ}C$ showed good recovery of discharge capacities through repeated cycles, and from SEM observation results these were considered as 1 hour in the range of $700{\sim}850^{\circ}C$ showed good recovery of discharge capacities through repeated cycles, and from SEM observation results these were considered asbeing due to increased electrode strength and small loss of porosity during heat-treatment. The electrode heat-treated for 1 hour at $900^{\circ}C$ showed poor discharge characteristics because of low porosity.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.2
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• pp.157-164
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• 1996

The AB5-type metal hydride electrodes using $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$(LM : Lanthaniumrich Mischmetal) alloy powders(${\leq}200$mesh) which were coated with 25wt% copper in an acidic bath were prepared with or without addition of 10wt% PTFE as a binder. Prior to electrochemical measurements, the electrodes were sintered at $40^{\circ}C$ for 1 and 2hrs in vacuum with Mm(mischmetal) and sponge type Ti getters. The properties such as maximum capacity, cycle life and mechanical strength of the negative electrode have been investigated. The surface analysis of the electrode was also obtained before and after charge-discharge cycling using scanning electron microscope(SEM). From the observations of electrochemical behavior, it was found that the sintered electrode shows a lower maximum discharge capacity compared with non-sintered electrode but it shows a better cycle life. For the both electrodes with or without addition of PTFE binder, the values of mechanical strength were obtained, and their values increased with increasing sintering time. However, there is little difference of discharge capacity for both electrodes.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.346-355
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• 2012

Recent in the world environmental issues and energy depletion problems have been received attention. One way to solve these problems is to use hybrid electric vehicles (HEVs). Therefore, the interest in HEV technology is higher than ever before. Viable candidates for the energy-storage systems in HEV applications may be absorbent glass mat (AGM) lead-acid, nickel-metal-hydride (Ni-MH) and rechargeable lithium batteries. The AGM battery has advantages in terms of relatively low cost, high charge efficiency, low self-discharge, low maintenance requirements and safety as compared to the other batteries. In order to implement HEV system in required more electric power commercial vehicles AGM batteries was connected to 2 series-2 parallels (2S2P). In this study, a one-dimensional modeling is carried-out to predict the behaviors of 2S2P AGM batteries system during charge and discharge. The model accounts for electrochemical reaction rates, charge conservation and mass transport. In order to validate the model, modeling results are compared with the experimentally measured data in various conditions.

• Journal of the Korean Electrochemical Society
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• v.2 no.2
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• pp.106-111
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• 1999

The effect of the MG on the electrochemical charge-discharge properties of $CaNi_5$ hydrogen storage alloys was investigated under Ar and $H_2$ atmosphere. $CaNi_5$ alloy was partially decomposed to CaO and Ni phase during the MG process. The decomposition of $CaNi_5$ alloy was enhanced by the MG process which leads to crash and reformation of oxide layer on the alloy surface. As the MG process time increased, initial discharge capacity of the electrode was reduced, but the decay rate of the capacity compared to $CaNi_5$ alloys was slower. It may be described that the degradation of $MG-CaNi_5$ electrode was caused by the reduction of the reversible hydrogen reaction sites and increasing polarization resistance of hydrogen adsorption resulted from phase decomposition and disorder during the MG process, and/or by hydroxide formation during the electrochemical charge-discharge cycles.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.69-74
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• 2006

The effects of mechanical grinding(MG) treatment on the hydrogen storage of $Mg_2Ni$ alloy and $Mg_2Ni$ composite alloy($Mg_2Ni+graphite$) were investigated by pressure-composition-temperature(PCT) measurement, the micro-electrode technique of electrochemistry and etc, in which PCT was measured at high temperature(around $300[^{\circ}C]$) of gas phase and a carbon-filament micro-electrode for electrochemical evaluation was manipulated to make electrical contact with the particle in 1M KOH aqueous solution. It was found that the hydrogenation properties of $Mg_2Ni$ and graphite composite particle were greatly improved by the mechanical grinding treatment by which the $Mg_2Ni$ and graphite composite alloys could be changed into microstructure and nano-level particles. namely; the hydrogen dissociation pressure of PCT measurement was decreased from 0.55[MPa] to 0.42[MPa] and hydrogenation peaks by micro-electrode were also observed more clearly on the same sample.

• Transactions of the Korean hydrogen and new energy society
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• v.9 no.4
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• pp.161-167
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• 1998

It has been investigated the effects of alloying elements and binders on the corrosion behavior of metal hydride electrodes for anode of Ni/MH secondary battery. The $AB_5$-type alloys, $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$ and $(LM)Ni_{3.6}Co_{0.7}Mn_{0.3}Al_{0.4}$, were used for the experiments. The electrodes were prepared by mixing and cold-pressing of alloy powders with Si sealent or PTFE powders, or cold-pressing the electroless copper coated alloy powders. The amount of copper coating was 20wt%. In order to examine corrosion behavior of the electrodes, the corrosion current and the current density, in 6M KOH aqueous solution after removal of oxygen in the solution, were measured by potentiodynamic and cyclic voltamo methods. The results showed that Co in the alloy increased corrosion resistance of the electrode whereas Ni decreased the stability of the electrode during the charge-discharge cycles. The electrode used Si sealant as a binder showed a lower corrosion current density than the electrode used PTFE and the electrode used Cu-coated alloy powders showed the best corrosion resistance.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.234-243
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• 1997

The crystal structure of arc melted $ZrV_{x}Mn_{1-x}Ni_{1.0},\;ZrV_{x}Mn_{0.8-x}Ni_{1.2},\;ZrV_{x}Mn_{0.6-x}Ni_{1.4}$ alloys which are known to have AB2 type Laves structure was investigated. They had mixed phases of C14 and C15. The radius ratio ($r_{A}/r_{B}$) of atoms in A site to that of B site was found to be an important parameter in explaining the omposition dependence of the crystal structure The C15 structure showed a linear increase with the ratio in as-cast conditions. However, the annealed alloys revealed a definite ratio at which the stability of both phases are divided distinctly. The composition of the alloys could be closely controlled by maintaining the argon pressure in the chamber over 1 arm during arc melting. In contrast, the alloy ingot melted in VIM showed a significant loss of hln.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.279-285
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• 2008

CNC (Carbon Nano Colloid) was used as an additive to the positive electrode to improve the discharge performance of sealed lead-acid batteries, The cathode active material ($PbO_2$) has a relatively low utility of less than 60 % compared with other kind of batteries, such as Ni-MH and Lithium ion, In this study, to overcome the above-mentioned problem we investigated the effects of CNC addition on the enhancement of electrical connection with not-utilized $PbO_2$ and resultantly electrical conductivity of electrode, We examined low rate discharge capacities, high rate discharge capacities and internal resistances of the batteries containing various amounts of CNC. From these results, we found out that the addition of CNC into the positive electrode made a significant improvement in high rate discharge capacity, We also suggested the optimum content of CNC material in positive electrode.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.2
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• pp.141-149
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• 1999

Recently the Ni/MH secondary battery has been studied extensively to achieve higher energy density, longer cycle life and faster charging-discharging rate etc. In this work, the electrode properties of $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$ alloy and $Ti_{0.6}Zr_{0.4}V_{0.6}Ni_{1.4}$ alloy with addition of Pd were investigated. These alloys did not show any change in XRD pattern by Pd addition. As Pd was added as alloy element, the activation behavior was not affected significantly in both $AB_2$ type and $AB_5$ type electrodes and, On charging and discharging in high current density, Discharge capacity with increasing of Pd content was more decreased. But cycle life was showed increasing. Especially the electrode of $Ti_{0.6}Zr_{0.4}V_{0.6}Ni_{1.4}+0.5wt%$ Pd alloy was not almost decreased discharge capacity for 400cycles.