• Journal of IKEEE
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• v.26 no.4
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• pp.531-536
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• 2022

In order to efficeintly manage a battery, it is important to accurately estimate and manage the SOH(State of Health) and RUL(Remaining Useful Life) of the batteries. Even if the batteries are of the same type, the characteristics such as facility capacity and voltage are different, and when the battery for the training model and the battery for prediction through the model are different, there is a limit to measuring the accuracy. In this paper, We proposed the entropy index using voltage distribution and discharge time is generalized, and four batteries are defined as a training set and a test set alternately one by one to predict the health status of batteries through linear regression analysis of machine learning. The proposed method showed a high accuracy of more than 95% using the MAPE(Mean Absolute Percentage Error).

• Resources Recycling
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• v.32 no.1
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• pp.13-20
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• 2023

The objective of this article is to summarize the commercial lithium ion battery (LIB) recycling processes in Korea and to suggest new direction for LIB recycling. A representative LIB recycler, SungEel Hitech Co. has successfully operated the LIB recycling process for over 10 years, and new recycling processes were recently proposed or developed by many recycling companies and battery manufacturers. In the new recycling processes, lithium is recovered before nickel and cobalt due to the rapid rise in lithium prices, and metal sulfate solution as final product of recycling process can be supplied to manufacturers. The main problem that the new recycling process will face is impurities, which will mainly come from end-of-life electric vehicles or new additives in LIB, although the conventional processes must be improved for mass processing.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.34-42
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• 2011

With the progress of USN technology, fields to which wireless sensor node is applicable are increased under a condition that it holds a lot of problems to solve for betterment. One of the problems which acts as an obstacle to USN industry diffusion is the wireless sensor node battery exchange to their individual life cycle. Exchanging the battery of so many sensor nodes one by one requires a great deal of times and costs. Such problem is against the convenience supply -aim by applying USN technology. In this paper, using RF wireless power transmission system that power transmission / harvesting module from a distance of 5 m and the power of 10 dBm with a current of 1 mA or more for Sensor Nodes in lithium-polymer battery charging system tested and verified.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.161-165
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• 2012

It is one of the most important to protect the battery over charging for stable use and to extend the life of battery which occurs with repeated charging and discharging. Various research have been studied to know the state of health, and in this paper the terminal voltage of battery is measured to calculate the state of charge simply. The circuit used comparator is designed and built not to fall under the specific voltage of battery. The designed circuit board is attached to the automatic water sanitizer device with a solar power system. The system is located in the water tank where there is not water and electric service, and confirmed that the state of working is good.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.419-426
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• 2014

The recent trend of performance increase in the smart mobile devices demands more power consumption and lower batter life time. Among three battery models of mathematical model, electrochemical model and electric model, the Thevenin's equivalent circuit with non-linear function model of SOC in the electrical model is widely used. However, the OCV results have only limited accuracy because of the characteristic shift caused by temperature and age and atypical impedance property that cannot expressed by electrical components. In this paper, the new battery model that improves the accuracy of the existing models is proposed. In the proposed simulator the mathematical model for SOC characteristic is improved and the adjustment for the temperature, the age of battery and atypical electrical characteristics. In the experimental results of predicting of the battery in the static and dynamic state, the proposed simulator shows improved MSE comparing to the results of the existing methods.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.223-229
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• 2023

Seawater batteries are next-generation secondary batteries that use seawater as a cathode. They utilize marine resources to provide competitive prices, high eco-friendliness, and a structure suitable for marine applications. Based on these advantages, pouch types and prismatic types have been studied and developed assuming natural seawater exposure. However, because of the electrical characteristics of the secondary battery, its capacity and internal resistance vary depending on the use environment. These characteristics are not only utilized for predicting the life of a battery but also have a direct effect on the capacity and power suitable for a specific situation. Therefore, the internal resistance was analyzed in this study by measuring the capacity depending on the seawater battery use environment and the state-of-charge-open-circuit-voltage measurement method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1419-1435
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• 2015

In this study an active RFID system of low power consumption is proposed, for which we improved the tag collection algorithm of ISO/IEC 18000-7 standard and significantly reduced the tag collection time. We classified the type of power consumption according to the operating mode of active RFID and proposed the method which can accurately estimate battery life time. By calculating the power consumptions of proposed and current methods, we can compare the battery life times of both methods. Through this analysis we can demonstrate the superiority of the proposed method in battery life time.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.91-97
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• 2020

Lithium-ion batteries (LIBs) have a longer lifespan, higher energy density, and lower self-discharge rates than other batteries, therefore, they are preferred as an Energy Storage System (ESS). However, during years 2017-2019, 28 ESS fire accidents occurred in Korea, and accurate capacity estimation of LIB is essential to ensure safety and reliability during operations. In this study, data-driven modeling that predicts capacity changes according to the charging cycle of LIB was conducted, and developed models were compared their performance for the selection of the optimal machine learning model, which includes the Decision Tree, Ensemble Learning Method, Support Vector Regression, and Gaussian Process Regression (GPR). For model training, lithium battery test data provided by NASA was used, and GPR showed the best prediction performance. Based on this study, we will develop an enhanced LIB capacity prediction and remaining useful life estimation model through additional data training, and improve the performance of anomaly detection and monitoring during operations, enabling safe and stable ESS operations.

• 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.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.147-154
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• 2013

This study reports on the development and investigation of a BMS module using a new algorithm on the driving performance and battery life of electric vehicles. Here, the initial SOC was calculated using an open circuit voltage (OCV) method and a current integral method was later applied to the BMS module. We verified the performance of the BMS module by comparing both the results of the in-vehicle test and the BMS simulator test. Our verification test showed good agreement between the results of experiments and simulation with a small error of ${\pm}0.8%$. Here, we confirmed that the present, newly-developed BMS module not only can predict the battery life but can also monitor SOC, pack voltage, and current temperature.