• Journal of Power Electronics
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• 제13권3호
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• pp.497-506
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• 2013

This paper proposes a new method to improve the available battery capacity in electric vehicles by connecting lead-acid batteries with lithium-ion battery in parallel to supply power. In addition, this method combines the discharge characteristics of batteries to improve their efficiency and lower their cost for electric vehicles. A lithium-ion battery set is used to connect with N sets of lead-acid batteries in parallel. The lead-acid battery supplies the initial power. When the lead-acid battery is discharged by the load current until its output voltage drops to the cut-off voltage, the power management unit controls the lead-acid battery and changes it to discharge continuously with a small current. This discharge can be achieved by connecting the lead-acid battery to a lithium-ion battery in parallel to supply the load power or to discharge its current to another lead-acid or lithium-ion battery. Experimental results demonstrates that the available capacity can be improved by up to 30% of the rated capacity of the lead-acid batteries.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.998-1002
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• 2008

The gel electrolytes were prepared with sulfuric acid and phosphoric acid, where hydrophilic fumed silica was used as a gelling agent. The influences of gel electrolyte on performance of the valve regulated lead acid (VRLA) batteries were investigated employing capacity tests, electrochemical impedance spectroscopy and scanning electron microscopy. The initial capacities of the sulfuric gel VRLA batteries were higher than that of phosphoric gel VRLA batteries. The sulfuric gel VRLA battery using 1.210 specific gravity of sulfuric acid with hydrophilic fumed silica exhibited the highest capacity of 0.828Ah. In the impedance measurements, the ohmic and charge transfer resistances for the phosphoric gel VRLA batteries were higher thanthat of sulfuric gel batteries. The morphology of electrodes of phosphoric gel VRLA batteries were more deteriorated in the SEM image.

• Journal of Power Electronics
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• 제15권5호
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• pp.1295-1304
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• 2015

In this paper, an approach to extend the life of lead-acid batteries through the elimination of sulfation with "rest time" using the pulse current of a conventional DPV (Differential Pulse Voltammetry) method is discussed. A new rest time without "0" current in "saw-tooth" pattern pulses is proposed to overcome the "0" current (blackout period), which is a shortcoming of DPV. This will enable the proposed method to be used in the loaded state. In the proposed approach, ESSs (Energy Storage Systems) were discharged for 5 h twice per day for 6 months on weekdays. To observe the changes in the lifespan of the systems, for the same period, the changes in the impedances of lead-acid batteries which were being charged e without charging and discharging were measure and compared. This study is focused on determining the effectiveness of lead-acid batteries as ESSs.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.75-80
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• 2002

Cycle life tests have been carried out to evaluate the influence of safety valve pressure on valve regulated lead/acid batteries under deep cycling applications. Batteries were cycled at 5 hour rates at 100% DOD, and safety valve pressure was set to 1.08 and 2.00 bar, respectively. The batteries lost 248.3 g and 235.3 g of water for each case after about 1,200 cycles, but the cyclic performances of the batteries were comparable. Most of the gas of the battery during discharging was hydrogen, and the oxygen concentration increased to 18% after 3 hours of charging. The micro structure of the positive active materials was completely changed and the corrosion layer of the positive grid was less than $50{\mu}m$, regardless of the pressure of the safety valve after cycle life tests. The cause of discharge capacity decrease was found to be water loss and the shedding of the positive active materials. The pressure of safety valve does not give little effect to the cyclic performances and the failure modes of the gelled electrolyte valve-regulated lead acid batteries.

• 대한임베디드공학회논문지
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• 제11권5호
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• pp.305-312
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• 2016

Modern embedded systems are typically operated by the rechargeable batteries in our daily life. Since charge of batteries is considered as an time consuming task, there have been extensive efforts to manage the charge time from the perspective of materials, circuits, and systems. Estimation of battery charge time is one of the essential information to design the charge circuitry. A compact macro model for the constant-current and constant-voltage charge protocol was recently introduced, which gives us a quick estimation of charge time with similar shape to the famous Peukert's law for discharge time estimation. The CC-CV charging protocol is widely used for Lithium-based batteries and Lead-acid batteries. In this paper, we characterize the lead-acid battery by measurement to extract the model coefficients, which was not covered by the previous studies. By our proposed model, the key coefficient Kcc results in 1.18-1.31, which is little bit higher than that of Lithium batteries. The accuracy of our model is within the range of ${\pm}10%$ error, which is compatible with the other studies such as Peukert's law.

• Corrosion Science and Technology
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• 제2권1호
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• pp.1-6
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• 2003

A comprehensive coverage of corrosion in batteries is rendered difficult by the wide choice of materials, environments and physical features as obtained in practical settings. Understanding of the complex processes that occur in these electrochemical systems gets clearer as new theoretical approaches backed by sophisticated analytical and characterization techniques continue to provide valuable insights which aid in controlling/mitigating wasteful corrosion reactions which affect battery shelf-life, cycle life, rate capability and capacity. In the light of the above, I limit myself to a discussion on corrosion aspects in representative system such as conventional Leclanche, lead-acid battery and magnesium batteries, and advanced lithium systems.

• 한국인터넷방송통신학회논문지
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• 제24권2호
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• pp.127-132
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• 2024

최근 이차전지는 다양한 산업 분야에서 사용되고 있다. 특히 소형 및 경량의 특성으로 스마트폰, 노트북, 태블릿 등 다양한 휴대용 전자기기에서 높은 에너지 밀도와 충·방전 효율을 토대로 전기자동차와 에너지저장시스템(Energy Storage System, ESS)의 핵심 부품으로 사용되고 있다. 하지만 이차전지의 과도한 충·방전에 따른 수명감소, 파열, 손상, 화재 등의 문제점이 발생하고 있다. 따라서 BMS(Battery Management System)를 통하여 과도한 충·방전을 보호하고 성능을 향상시킨다. 하지만 실제 리튬이온 배터리를 사용하여 BMS의 차단 및 보호범위 설정하는 데 있어서 이차전지의 수명감소, 파열, 손상, 화재의 문제점이 따른다. 따라서 본 논문에서는 배터리 충방전기와 시뮬레이터를 활용하여 이차전지 중 사용이 높은 리튬이온 배터리와 납축전지의 충전 및 방전 특성을 살펴본다.

• 전기화학회지
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• 제15권3호
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• pp.160-164
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• 2012

납축전지는 낮은 가격과 가역적인 반응으로 재사용이 가능하고 높은 기전력을 가져 우리 생활에 가장 널리 사용되고 있지만 제한된 사이클 수명을 가지고 있다. 제한된 사이클 수명은 충전과 방전 과정을 거치면서 전극 표면에 형성되는 $PbSO_4$의 재결정 반응인 Sulfation 때문이다. 본 연구에서는 납축전지의 사이클 진행에 따른 전극 표면 변화를 관찰하였고, 납축전지에 펄스 전류를 인가하여 재생한 전극 표면을 관찰하였다. 납축전지는 600 사이클 후 재생 시 초기 용량의 약 84%까지 용량이 회복하는 특성을 관찰하였다.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.460-465
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• 2013

Electrical equipments of nuclear power plant are divided into class 1E and non-class 1E. Electrical equipment and systems that are essential to emergency reactor shutdown, containment isolation, reactor core cooling, and containment and reactor heat removal, are classified as class 1E. batteries of nuclear power plant are divided into four channels, which are physically and electrically separate and independent. The battery bank of class 1E DC power system of the nuclear power plant use lead-acid batteries in present. The lead acid battery, which has a high energy density, is the most popular form of energy storage. Kt factor of lead-acid battery is used to determine battery size and it is one of calculatiing coefficient for capacity. this paper analyzes Kt factor of lead-acid battery for the DC power system of nuclear power plant. In addition, correlation between Kt parameter and peukert's exponent of lead-acid battery for nuclear plant are discussed. The analytical results contribute to optimize of determining size Lead-acid battery bank.

• 전기화학회지
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• 제13권2호
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• pp.128-131
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• 2010

납축전지 전류 집전체로서의 가능성을 보기위해 납 도금된 그라파이트 시트를 적용하여 평가하였다. 전기화학적 특성을 평가하기 위해 순환 전압전류법을 실시하였다. 납 도금된 그라파이트 시트는 납축전지의 음극으로 운용되는 전압범위에서 전기화학적으로 안정하였으나, 양극으로 운용되는 전압범위에서는 산소발생과 황산의 인터칼레이션으로 인해 전기화학적으로 불안정하였다. 납 도금된 그라파이트와 주조된 납 기판을 음극 전류집전체로 사용하여 전지를 제작하고, 방전 성능을 평가하였다. 납 도금된 그라파이트 시트를 적용한 납축전지가 금속 납 전류 집전체를 적용한 전지보다 더 높은 용량을 나타내었고, 에너지밀도 또한 더 높았다.