• 반도체디스플레이기술학회지
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• 제10권4호
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• pp.25-29
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• 2011

Emerging demands for rechargeable battery for various applications needs more effective battery management system such as the prediction of the usable time about a battery. Many prediction methods have been suggested but none of them come into bounds of reliability. In this paper, we proposed a new prediction algorithm for the remaining capacity of a rechargeable battery by using the transformed curve based on its impedance. Hardware for monitoring a battery was designed and made. Through a series of experiment, we showed the effectiveness of the proposed prediction algorithm of a battery's remaining capacity.

• 한국군사과학기술학회지
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• 제19권1호
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• pp.26-34
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• 2016

Military devices and systems powered by batteries need to operate at extreme temperature and estimate the available capacity of the battery at different temperature conditions. However, accurate estimation of battery capacity is challenging due to the temperature-sensitive nature of electrochemical energy storage. In this paper, Peukert's equation with temperature factor is derived, and methods for estimating the absolute capacity of lithium-polymer battery and the state-of-charge(SOC) with respect to varying currents and temperatures are presented. The proposed estimation method is experimentally verified under three different discharge currents(0.5 A, 1 A, 3 A) and six different temperatures ranging from -30 to 45 deg. C. The results show the proposed method reduces the Peukert's estimation error by up to 30 % under or at extreme condition.

• Journal of Electrochemical Science and Technology
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• 제13권4호
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• pp.472-478
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• 2022

Solar energy harvesting is practiced by various nations for the purpose of energy security and environment preservation in order to reduce overdependence on oil. Converting solar energy into electrical energy through Photovoltaic (PV) module can take place either in on-grid or off-grid applications. In recent time Lithium battery is exhibiting its presence in on-grid applications but its role in off-grid application is rarely discussed in the literature. The preliminary capacity and Peukert's study indicated that the battery quality is good and can be subjected for life cycle test. The capacity of the battery was 10.82 Ah at 1 A discharge current and the slope of 1.0117 in the Peukert's study indicated the reaction is very fast and independent on rate of discharge. In this study Lithium Iron Phosphate battery (LFP) after initial characterization was subjected to life cycle test which is specific to solar off-grid application as defined in IEC standard. The battery has delivered just 6 endurance units at room temperature before its capacity reached 75% of rated value. The low life of LFP battery in off-grid application is discussed based on State of Charge (SOC) operating window. The battery was operated both in high and low SOC's in off-grid application and both are detrimental to life of lithium battery. High SOC operation resulted in cell-to-cell variation and low SOC operation resulted in lithium plating on negative electrode. It is suggested that to make it more suitable for off-grid applications the battery by default has to be overdesigned by nearly 40% of its rated capacity.

• Journal of Platform Technology
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• 제11권2호
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• pp.54-65
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• 2023

전기자동차에 사용되는 배터리는 전기자동차의 특성상 정격용량이 매우 커다란 배터리이다. 전기자동차를 장기간 운행하거나 교통사고로 전기자동차가 폐차되게 되면 전기자동차용 배터리는 폐배터리가 된다. 폐차되는 차량이더라도 전기자동차용 폐배터리에 남아 있는 용량은 다른 용도로 사용하기에 충분하다. 자동차용 폐배터리는 매우 고가이기때문에 재활용 및 재사용이 필요하지만 재활용 및 재사용을 위한 폐배터리 성능등급 측정기준이 부족한 문제가 있었다. 폐배터리의 잔존용량을 측정하는 방법으로 가장 안정적이고 신뢰할 수 있는 방법은 완전 충·방전을 이용하여 배터리의 잔존용량을 측정하는 것이다. 하지만 이러한 완전 충·방전에 방식에 의한 검사 방법은 배터리의 용량에 따라 다르지만 검사하는데 하루 이상이 걸리는 단점을 가지고 있으며 많은 사람들이 이러한 문제를 해결하기 위하여 많은 노력을 하고 있다. 본 논문에서는 전기자동차 배터리에 대한 검사 시간을 줄일 수 있는 방법으로 셀간 전압 편차를 활용한 전기자동차 배터리 잔존용량 분석 기법을 연구 분석하였다. 이를 위하여 완전 충·방전 기반의 용량 측정시스템을 구성하고 코나 폐배터리를 이용하여 실험데이터를 수집하였고 배터리 팩을 구성하고 있는 배터리 셀간 전압 편차와 잔존용량과의 상관관계를 분석하여 배터리 검사에 활용할 수 있는지를 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.170-172
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• 2005

Internal battery ohmic measurements have been a hot topic amongst battery users and battery manufacturers. As a battery deteriorates and loses its capacity, the internal resistance of the battery increases. Everyone seems to agree that measuring the internal parameters of a cell can be very useful in determining a battery's state of health. In this paper experiences show that if a cell's resistance increases by more than25% above its baseline value(known good resistance of new 100% capacity cell), the cell will no loger be able to deliver 80% or more of the rated capacity.

• 전기학회논문지
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• 제67권1호
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• pp.38-45
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• 2018

In September 2016, the government decided to apply a REC 5.0 weighting to solar-battery ESS to increase the supply of renewable energy. In this paper, we calculated the optimal capacity of battery ESS which maximizes the revenue when solar is linked with battery ESS. In the case study, the optimal capacity was calculated by applying the conservative REC price, and we studied sensitivity analysis about battery price and real-time REC price.

• 한국산학기술학회논문지
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• 제6권5호
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• pp.396-400
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• 2005

소규모 독립형 태양광발전시스템의 안정적인 설계를 위해서는 태양전지와 배터리 용량이 매우 중요한 요소이다. 태양전지 및 배터리의 용량산정이 잘못되면 시스템의 동작이 불안정해지고 잦은 고장의 원인이 된다. 따라서 본 논문에서는 안정적인 태양광발전시스템의 설계를 위해 부하특성을 고려한 태양전지와 배터리 용량산정 방안을 제시하였다.

• Journal of Electrochemical Science and Technology
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• 제13권3호
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• pp.323-338
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• 2022

Heat generation and temperature of a battery is usually presented by an equation of current. This means that we need to adopt time domain calculation to obtain thermal characteristics of the battery. To avoid the complicated calculations using time domain, 'state of charge (SOC)' can be used as an independent variable. A SOC based calculation method is elucidated through the comparison between the calculated results and experimental results together. Experiments are carried for rapid resistive discharge of a large-capacitive lithium secondary battery to evaluate variations of cell potential, current and temperature. Calculations are performed based on open-circuit cell potential (SOC,T), internal resistance (SOC,T) and entropy (SOC) with specific heat capacity.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3221-3224
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• 2010

This study investigates the requirements of lithium-air cathodes, which directly influence discharge capacity. The cathodes of Li-air cell are made by using five different carbon materials, such as Ketjen black EC600JD, Super P, Ketjen black EC300JD, Denka black, and Ensaco 250G. The Ketjen black EC600JD provides discharge capacity of 2600 mAh/g per carbon weight, while that of Ensaco 250G shows only 579 mAh/g. To figure out the differences of discharge capacity from carbon materials, their surface area and pore volume are analyzed. These are found out to be the critical factors in determining discharge capacity. Furthermore, carbon loading on Ni foam and amounts of electrolyte are significant factors that affect discharge capacity. In order to investigate catalyst effect, electrolytic manganese dioxide (EMD) is incorporated and delivered 4307 mAh/g per carbon weight. This infers that EMD facilitates to break $O_2$ interactions and leads to enhance discharge capacity.

• Journal of Power Electronics
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• 제13권3호
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• pp.429-436
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• 2013

Online simulations are utilized to reduce time and cost in the development and performance optimization of plug-in hybrid electric vehicle (PHEV) and electric vehicles (EV) systems. One of the most important factors in an online simulation is the accuracy of the model. In particular, a model of a battery should accurately reflect the properties of an actual battery. However, precise dynamic modeling of high-capacity battery systems, which significantly affects the performance of a PHEV, is difficult because of its nonlinear electrochemical characteristics. In this study, a dynamic model of a high-capacity battery cell for a PHEV is developed through the extraction of the equivalent impedance parameters using electrochemical impedance spectroscopy (EIS). Based on the extracted parameters, a battery cell model is implemented using MATLAB/Simulink, and charging/discharging profiles are executed for comparative verification. Based on the obtained results, the model is optimized for a high-capacity battery cell for a PHEV. The simulation results show good agreement with the experimental results, thereby validating the developed model and verifying its accuracy.