• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.24 no.2
• /
• pp.133-138
• /
• 2024

Lithium-ion batteries are used in many fields due to their high energy density, fast charging conditions, and long cycle life. However, overcharging, over-discharging, physical damage, and use of lithium-ion batteries at high temperatures can reduce battery life and cause damage to people due to fire or explosion due to damage to the protection circuit. In order to reduce the risk of these batteries and improve battery performance, the characteristics of the charging and discharging process must be analyzed and understood. Therefore, in this paper, we analyze the charging and discharging characteristics of lithium-ion batteries using a battery charger and discharger and simulator to reduce the risk of loss of life due to overcharge and overdischarge, as well as casualties from fire and explosion due to damage to the protection circuit.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.4
• /
• pp.669-676
• /
• 2024

This study aims to evaluate battery damage and heat transfer mechanisms through fire tests on lithium-ion batteries, and to explore ways to improve the efficiency and safety of battery management systems (BMS). Temperature changes in each sector are measured at points T1, T2, and T3 observing and recording the reactions of surrounding cells for 10 minutes after applying electricity to the ignition electrode. The results show that the batteries in sectors A and B fully ignite, causing severe physical damage, while the batteries in sector C do not ignite and sustain minimal damage. This confirms that the distance between sectors plays a crucial role in reducing ignition and heat propagation. The study suggests that considering the distance between sectors in the design of thermal management systems for lithium-ion batteries can significantly mitigate ignition and heat spread. Future experiments with various battery models and conditions will further propose the ways to enhance the efficiency and safety of BMS.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1009-1011
• /
• 2002

Some defective cells in the battery bank of power systems using batteries result in deterioration of the performance of the total battery bank. Consequently, the battery bank can't perfectly back up the system in occurrence of any power problems and the overcharge of defective cells may lead to their explosion or the occurrence of fire. The developed battery management system in this study enables operators to telemeter and analyze internal resistance, voltages, currents, and temperatures of batteries at remote sites through a PC, so they can detect defective cells before the occurrence of power problems. And adoption of this system ensures extension of battery life.

• Carbon letters
• /
• v.12 no.3
• /
• pp.180-183
• /
• 2011

Li metal is accepted as a good counter electrode for electrochemical impedance spectroscopy (EIS) as the active material in Li-ion and Li-ion polymer batteries. We examined the existence of signal noise from a Li-metal counter quantitatively as a preliminary study. We suggest an electrochemical cell with one switchable electrode to obtain the exact impedance signal of active materials. To verify the effectiveness of the switchable electrode, EIS measurements of the solid electrolyte interphase (SEI) before severe $Li^+$ intercalation to SFG6 graphite (at > ca. 0.25 V vs. Li/$Li^+$) were taken. As a result, the EIS spectra without the signal of Li metal were obtained and analyzed successfully for the following parameters i) $Li^+$ conduction in the electrolyte, ii) the geometric resistance and constant phase element of the electrode (insensitive to the voltage), iii) the interfacial behavior of the SEI related to the $Li^+$ transfer and residence throughout the near-surface (sensitive to voltage), and iv) the term reflecting the differential limiting capacitance of $Li^+$ in the graphite lattice.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.701-710
• /
• 2017

This paper presents a five-level PWM inverter using series and parallel connection of voltage sources. The alternative connection is done by an auxiliary circuit consisted of a switch, three diodes, and two batteries. The auxiliary circuit is located between input dc voltage source and H-bridge cell. Thanks to the auxiliary circuit, the proposed inverter synthesizes five-level output voltage in an effective way. Topologically both batteries are charged and discharged in the same rate, so it does not need to apply battery voltage balancing control method. Theoretical analysis of the proposed inverter is verified by computer-aided simulation and experiment based on a prototype of 1kW.

• Journal of the Korean Ceramic Society
• /
• v.35 no.9
• /
• pp.995-1001
• /
• 1998

As a basic study for cathode materials of {{{{ { {LiMn }_{2 }O }_{4 } }}-based lithium-ion secondary batteries Li({{{{ { { { {Mn }_{1-$\delta$ }Nb }_{$\delta$} )}_{2 }O }_{4 } }} ($\delta$=0.05, 0.1, 0.2) materials which Nb is substituted for Mn were synthesized by the solid state reaction at 80$0^{\circ}C$ and 110$0^{\circ}C$ respectively. The second phase {{{{ { LiNbO}_{3 } }} appeared above $\delta$=0.1 As the result of im-pedance analysis as the amount of substituted Nb increased the resistivity of grain boundary increased greatly. Compared to undoped-{{{{ { {LiMn }_{2 }O }_{4 } }} the electrical conductivity of Li({{{{ { { { {Mn }_{1-$\delta$ }Nb }_{$\delta$} )}_{2 }O }_{4 } }} decreased slightly but is charging capacity and potential plateau increased.

• Journal of Electrochemical Science and Technology
• /
• v.10 no.4
• /
• pp.373-380
• /
• 2019

In this paper, we report the preparation of a flexible, self-standing and binder-free carbon nanotubes (CNTs) electrode with an electro-generated current collector. The copper current collector layer was electrodeposited on the backside of CNTs self-standing film obtained by a simple filtration process. The obtained CNTs-Cu assembly was used as a negative electrode in Li-ion batteries exhibiting good performance along with proving its applicability in flexible batteries.

• Journal of electromagnetic engineering and science
• /
• v.16 no.4
• /
• pp.210-213
• /
• 2016

This paper presents a wireless power charging system for rechargeable batteries. Recently, misalignment between transmitting coil and receiving coils has been a significant factor to wireless power charging systems, which are prone to lateral and angular misalignment. Unfortunately, the batteries can be easily rolled because of the shape, and coils are often misaligned while charging devices, in practical situations. This paper presents the wireless power battery charging system. In order to solve the angular misalignment, two perpendicular coil having structure of 'plus (+)' shape was proposed. To validate the results, the proposed wireless power charging system was implemented at 6.78 MHz using loosely coupled resonant coils, and the system was verified as being robust to misalignment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.6
• /
• pp.399-406
• /
• 2014

Thermal batteries are used for military power sources that require robustness and long storage life such as missiles and torpedoes. $FeS_2$ powder is currently used for cathode materials because of its high specific energy density, environmental non-toxicity and low cost. However, large particle size of conventional $FeS_2$ has been deterred its possible application for higher power thermal batteries. In order to improve the power density, high energy ball milling of $FeS_2$ has been introduced to crush the micron-sized $FeS_2$. Discharge characteristics of the single cells fabricated with nano-materials and conventional $FeS_2$ powder were evaluated.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2561-2567
• /
• 2018

The extension of DC battery backup time in the DC power supply system of nuclear power plants (NPPs) remains a challenge. The lead-acid battery is the most popular at present. And it is generally the most popular energy storage device. However, extension of backup time requires too much space. The lithium-ion battery has high energy density and advanced gravimetric and volumetric properties. The aim of this paper is development of the sizing formula of stationary lithium-ion batteries. The ongoing research activities and related industrial standards for stationary lithium-ion batteries are reviewed. Then, the lithium-ion battery sizing calculation formular is proposed for the establishment of industrial design standard which is essential for the design of stationary batteries of nuclear power plants. An example of calculating the lithium-ion battery capacity for a medium voltage UPS is presented.