• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.1-8
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• 2021

Currently, lithium-ion batteries are mainly used in energy storage equipment products including automobiles. This can be exposed to dangerous situations such as explosions in the event of incorrect battery management conditions that are overcharged or left in high temperature conditions. It also causes a situation battery cannot be used when it has been over discharged. Therefore, a system that manages the state of the battery is required. The battery management system aims to obtain optimum battery efficiency by accurately recognizing the state of the battery and keeping the voltage of each cell constant. In this paper, we develop a lithium-iron phosphate battery that has higher safety than a general lithium-ion battery. Then, in order to manage this, we try to develop the algorithm of the BMS module based on the Bluetooth communication using the MATLAB-SIMULINK.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.75-76
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• 2016

The relationship of widely used Open circuit Voltage (OCV) versus State of Charge (SOC) is critical for any reliable SOC estimation technique. However, the hysteresis existing in all type of battery which has been come to the market leads this relationship to a complicated one, especially in Lithium Iron Phosphate (LiFePO4) battery. An accurate model for hysteresis phenomenon is essential for a reliable SOC identification. This paper aims to investigate and propose a method for hysteresis modeling. The SOC estimation is done by using Extended Kalman Filter (EKF), the parameter of the battery is modeled by Auto Regressive Exogenous (ARX) and estimated by using Recursive Least Square (RLS) filter to tract each element of the parameter of the model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.61-67
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• 2018

High-power lithium batteries are suitable for equipment with high power output needs, such as for ESS's initial start-up. However, their management cost is increased by the installation of air-conditioning to minimize the risk of explosion due to internal temperature rise and also by a restriction on the number of charge/discharge cycles. High-capacity flow batteries, on the other hand, have many advantages. They can be used for over 20 years due to their low management costs, resulting from no risk of explosion and a high number of charge/discharge cycles. In this paper, we propose an ESS based on hybrid batteries that uses a lithium iron phosphate battery (LiFePO) at the initial startup and a vanadium redox flow battery (VRFB) from the end of the transient period, with a bi-directional PCS to operate two batteries with different DC voltage levels and using an efficient energy management control algorithm.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2698-2700
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• 2010

• Clean Technology
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• v.30 no.1
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• pp.28-36
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• 2024

As demand for electric vehicles increases, the market for lithium-ion batteries is also rapidly increasing. The battery life of lithium-ion batteries is limited, so waste lithium-ion batteries are inevitably generated. Accordingly, lithium was selectively preleached from waste lithium iron phosphate (LiFePO₄, hereafter referred to as the LFP) cathode material powder among lithium ion batteries, and iron phosphate (FePO₄) powder was recovered. The recovered iron phosphate powder was mixed with alkaline sodium carbonate (Na₂CO₃) powder and heat treated to confirm its crystalline phase. The heat treatment temperature was set as a variable, and then the leaching rate and powder characteristics of each ingredient were compared after water leaching using Di-water. In this study, lithium showed a leaching rate of approximately 100%, and in the case of powder heat-treated at 800 ℃, phosphorus was leached by approximately 99%, and the leaching residue was confirmed to be a single crystal phase of Fe₂O₃. Therefore, in this study, lithium, phosphorus, and iron components were individually separated and recovered from waste LFP powder.

• Resources Recycling
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• v.32 no.3
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• pp.9-17
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• 2023

Efforts are currently underway to develop a method for efficiently recovering lithium from the cathode material of waste lithium iron phosphate batteries (LFP). The successful application of lithium battery recycling can address the regional ubiquity and price volatility of lithium resources, while also mitigating the environmental impact associated with both waste battery material and lithium production processes. The isomorphic substitution leaching process was used to recover lithium from spent lithium iron phosphate batteries. Lithium was leached by the isomorphic substitution of Fe²⁺ in LFP using a relatively inexpensive ferric chloride etching solution as a leaching agent. In the study, the leaching rate of lithium was compared using the ferric chloride etching solution at various multiples of the LFP molar ratio: 0.7, 1.0, 1.3, and 1.6 times. The highest lithium leaching rate was shown at about 98% when using 1.3 times the LFP molar ratio. Subsequently, to eliminate Fe, the leachate was treated with NaOH. The Fe-free solution was then used to synthesize lithium carbonate, and the harvested powder was characterized and validated. The surface shape and crystal phase were analyzed using SEM and XRD analysis, and impurities and purity were confirmed using ICP analysis.

• Journal of Electrochemical Science and Technology
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• v.13 no.4
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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 Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.635-641
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• 2016

In order to drive a hybrid propulsion device which combines an engine and an electric propulsion unit, battery packs that contain dozens of unit cells consisting of a lithium-based battery are used to maintain the power source. Therefore, it is necessary to more strictly manage a number of battery cells at any given time. In order to manage battery cells, generally voltage, current, and temperature data under load condition are monitored from a personal computer. Other important elements required to analyze the condition of the battery are the internal resistances that are used to judge its state-of-health (SOH) and the open-circuit voltage (OCV) that is used to check the battery charging state. However, in principle, the internal resistances cannot be measured during operation because the parallel equivalent circuit is composed of internal loss resistances and capacitance. In most energy storage systems, battery management system (BMS) operations are carried out by using data such as voltage, current, and temperature. However, during operation, in the case of unexpected battery cell failure, the output voltage of the power supply can be changed and propulsion of the hybrid vehicle and vessel can be difficult. This paper covers the implementation of a high safety battery management system (HSBMS) that can estimate the OCV while the device is being driven. If a battery cell fails unexpectedly, a DC power supply with lithium iron phosphate can keep providing the load with a constant output voltage using the remainder of the batteries, and it is also possible to estimate the internal resistance.

• Journal of the Korean Electrochemical Society
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• v.8 no.4
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• pp.168-171
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• 2005

The electrochemical properties of $LiFePO_4$ as a cathode for Li-ion batteries were improved by incorporating conductive carbon into the $LiFePO_4$. X-ray diffraction analysis and SEM observations revealed that the carbon-coated $LiFePO_4$ consisted of fine single crystalline particles, which were smaller than the bare $LiFePO_4$. The electrochemical performance of the carbon-coated $LiFePO_4$ was tested under various conditions. The carbon-coated $LiFePO_4$ showed much better performance in terms of the discharge capacity and cycling stability than the bare $LiFePO_4$. The improved electrochemical performances were found to be attributed to the reduced particle size and enhanced electrical conductivity of the $LiFePO_4$ by the carbon.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.836-840
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• 2011

This study examines the effects of a carbon coating on the electrochemical performances of $LiFePO_4$. The results show that the capacity of bare $LiFePO_4$ decreased sharply, whereas the $LiFePO_4$/C shows a well maintained initial capacity. The Li ion diffusivity of the bare and carbon coated $LiFePO_4$ is calculated using cyclic voltammetry (CV) to determine the correlation between the electrochemical performance of $LiFePO_4$ and Li diffusion. The diffusion constants for $LiFePO_4$ and $LiFePO_4$/C measured from CV are $6.56{\times}10^{-16}$ and $2.48{\times}10^{-15}\;cm^2\;s^{-1}$, respectively, indicating considerable increases in diffusivity after modifications. The Li ion diffusivity (DLi) values as a function of the lithium content in the cathode are estimated by electrochemical impedance spectroscopy (EIS). The effects of the carbon coating as well as the mechanisms for the improved electrochemical performances after modification are discussed based on the diffusivity data.