• 한국화재소방학회논문지
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• 제33권1호
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• pp.23-29
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• 2019

리튬이온 배터리와 같은 충전식 배터리는 에너지의 저장장치로서 최근의 에너지 이용의 변화에 따라 크게 주목받고 있을 뿐 아니라 실제로 다양한 소형 전기기기 및 전기 자동차의 전기에너지 저장시스템으로 폭넓게 적용되고 있다. 하지만 리튬이온 배터리는 화재나 폭발 등의 위험성이 항상 존재하여 사용의 폭을 제한시키고 있다. 배터리화재가 일반적인 화재와의 다른 특성은 여러 가지가 있지만 그 중에 가연물질이 전해질에서 이온화 되어있다는 특성이다. 본 연구에서는 배터리 화재를 이해하기 위해서 양이온과 전자 등으로 이온화된 메탄 제트화염에서의 연소특성을 실험적으로 관찰하였다. 화염 형상 및 화염안전성은 현재의 실험조건에서는 연료 이온화 효과가 없었고, 제트화염 후류에서 측정한 CO와 NOx의 농도가 이온화연료에서 모두 감소하는 것을 확인할 수 있었다. 또한 이온화 메탄 연소특성의 파라미터 연구를 위하여 수치해석의 반응기구를 수소첨가의 형태로 단순화하여 이온화연료의 연소특성을 모사할 수 있는지에 대한 모델링 검토를 수행하였다. 연료 이온화의 영향으로 수소의 농도는 증가시키되 반응 후 온도는 일정함을 가정하여 모델링하면 실험결과와 일치하는 결과를 얻을 수 있었다.

• 한국화재소방학회논문지
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• 제33권2호
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• pp.98-106
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• 2019

차량의 내비게이션과 블랙박스의 보조배터리로 리튬배터리가 사용되고 있어 리튬배터리와 관련된 차량화재가 발생하고 있다. 발화개소 내에 리튬배터리가 있을 때, 리튬배터리에서 발화된 것인지 화재로 인해 리튬배터리가 피해를 입은 것인지를 판별하는 화재조사 기법이 정립되어 있지 않다. 이 논문에서는 리튬배터리와 관련된 차량화재 사례들을 소개하고, 리튬배터리의 화재발생 원인을 분석하며, 리튬배터리에서 발화된 것인지 외부에서 발화된 후 리튬배터리가 화재로 인한 피해를 입은 것인지를 객관적으로 판별할 수 있는 화재조사기법을 제안하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1555-1570
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• 2016

For monitoring forest fires, a real-time system to prevent fires in wider areas should be supported consistently. However, there has still been a lack of the support for real-time system related to forest fire monitoring. In addition, the 'real-time' processing in a forest fire detection system can lead to excessive consumption of energy. To solve these problems, the intelligent data acquisition of sensing nodes is required, and the maximum energy savings as well as rapid and accurate detection by flame sensors need to be done. In this regard, this paper proposes a node built-in filter algorithm for intelligent data collection of sensing nodes for the rapid detection of forest fires with focus on reducing the power consumption of the remote sensing nodes and providing efficient wireless sensor network-based forest environment monitoring in terms of data transmission, network stability and data acquisition. The experimental result showed that battery life can be extended through the intelligent sampling of remote sensing nodes, and the average accuracy of the measurement of flame detection based on the distance is 44%.

• 자동차안전학회지
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• 제14권1호
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• pp.55-61
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• 2022

Along with global environmental issues, the size of the electric vehicle market has recently skyrocketed. Various efforts have been made to extend mileage, one of the biggest problems of the electric vehicles, and development of batteries with high energy densities has led to exponential growth in mileage and performance. However, proper thermal management is essential because these high-performance batteries are affected by continuous heat generation and can cause fires due to thermal runaway phenomena. Therefore, thermal management of the battery is studied through the optimal design of the guide vanes, while utilizing the existing battery casing to ensure the safety of the electric vehicles. A battery from T-company, one of a manufacturer of the electric vehicles, was used for the research, and the commercial CFD software, ANSYS CFX V20.2, was used for analysis. The guide vanes were derived through optimal design based on a genetic algorithm with flow analysis. The optimized guide vanes show improved heat removal performance.

• 스마트미디어저널
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• 제12권11호
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• pp.103-112
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• 2023

최근 리튬이온 배터리 사용이 늘어남에 따라 배터리 화재 및 사고 예방의 필요성이 대두되고 있다. 사고 예방을 위해서는 배터리 SOH(State of Health)를 예측하여 열화가 많이 진행된 배터리의 교체 시기를 확인하는 것이 필요하다. 본 논문에서는 배터리의 충전 과정에서 얻을 수 있는 최대 전압 도달 시간, 전류 변화 시간, 최대 온도 도달 시간, IC(Incremental Capacity) 등 4가지 배터리 열화 특성과 어텐션 메커니즘을 이용한 장단기 메모리(Long Short Term Memory, LSTM)를 사용하여 배터리의 열화 상태를 예측하는 모델을 제안한다. NASA에서 제공하는 배터리 데이터 세트를 사용해 제안하는 모델의 성능을 측정한 결과 일반적인 LSTM 모델을 사용하는 경우보다 예측성능의 개선을 확인할 수 있었고, 특히 배터리 교체 주기에 가까운 SOH 90-70% 구간에서 더 우수한 성능을 보였다.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.63-70
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• 2024

Lithium-ion batteries (LIB) are widely used in various sectors, such as transportation (e.g., electric vehicles (EV)) and energy (e.g., energy storage facilities) due to their high energy density, broad operating temperature (-20 ℃ ~ 60 ℃), and high capacities. LIBs are powerful but fragile on external factors, including pressure, physical damage, overheating, and overcharging, that cause thermal runaway causing fires and explosions. During a LIB fire, a large amount of oxygen is generated from the decomposition of ionogenic materials. A water fire extinguisher that helps with cooling and suffocating must be essentially required at the same time. In fact, however, it is difficult to suppress LIB fires in the case of EVs because a LIB is installed with a battery pack housing that interrupts direct extinguishing by water. Thus, this study aims to investigate effective fire extinguishing measurements for LIB fires by using an EV. Relevant documents, including research articles and reports, were reviewed to identify effective ways of LIBs fire extinguishing. A real-scale fire experiment generating thermal runaway was carried out to figure out the combustion characteristics of EVs. This study revealed that the most effective fire extinguishing measurements for LIB fires are applying fire blankets and water tanks. However, there is still a lack of adequate regulation and guidelines for LIB fire extinguishment. Taking this into account, developing functional fire extinguishment measurements and available regulatory instruments is an urgent issue to secure the safety of firefighters and citizens.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.92-99
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• 2012

It is often thought that because no-start motor vehicles cannot start an engine, a fire cannot occur for motor vehicle causes. However, although the engine cannot start up, some parts may be live with electricity if a battery is connected. If the parts have problems, a fire can occur. This study analyzed the causes of fires occurring when a motor vehicle was loaded onto a tow truck to service no-start. It is suggested that no-start motor vehicles should separate a battery terminal to prevent a fire. And this fire is related to automotive products liability.

• 한국지열·수열에너지학회논문집
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• 제17권2호
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• pp.1-10
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• 2021

Lithium-ion batteries with high energy density, long cycle life and other advantages, have been widely used to energy storage systems(ESS). But as ESS fires frequently occur, the safety concern has become the main obstacle that hinders the large-scale applications of lithium-ion batteries. Especially, thermal runaway is the key scientific problem in battery safety research. Therefore, in this study, we performed a numerical analysis on the thermal runaway phenomenon of NCM111, NCM523 and NCM622 batteries using a two-dimensional analysis model. The results show that the two-dimensional simulation results are generally matched with three-dimensional simulation. Also, In the case of NCM111 with a low Ni content in the temperature range used in this study, thermal runaway phenomenon does occurred very slowly, but as the Ni content is increased, the thermal runaway phenomenon occurs rapidly and the thermal stability tends to be decreased. And, in NCM523 and NCM622 batteries, chain reactions occur almost simultaneously, but in the case of NCM111 battery, it is found that after the SEI(Solid Electrolyte Interface) layer decomposition reaction, the cathode-electrolyte reaction is appeared sequentially. After that, the anodic decomposition reaction is increased and leads to the thermal runaway reaction.

• 한국안전학회지
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• 제32권6호
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• pp.22-28
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• 2017

According to the National Fire Data System (NFDS), more than 5,000 vehicle fires have occurred every year for the last 10 years. Vehicle fires are primarily caused by mechanical (breaking system and engine), electrical (wiring and battery), and chemical (oil and fuel gas leakage) problems. The electrical factor has increased with the installation of driver convenience equipment. For example, today, the black box is widely used to provide video data recording of motor vehicle accidents. The black box consists of a front camera, rear camera, and wires. The black box wires are directly connected to the junction box or fuse box from the start battery that operates to provide normal on power supplying for engine stop. It is extremely dangerous when the wires short circuit due to insulation aging, mechanical and electrical stress, etc. In this study, the black box wiring fire risk have been analyzed and investigated when the steady state and abnormal operations, and under the following conditions: wiring arrangements with a high temperature condition, insulation aging, poor contact, and short circuits. The results showed that black box wiring short circuits had a higher fire risk than the other fire hazard elements. To prevent fire hazards caused by black box wiring, the black boxes must be installed by qualified service personnel. Do not modify the wiring, remove the fuse and secure the wiring using cable ties or insulation tape.

• 한국안전학회지
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• 제33권1호
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• pp.22-27
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• 2018

Many electronic devices are powered by various rechargeable batteries such as lithium-ion recently, and occasionally the batteries undergo thermal runaway and cause fire, explosion, and other hazards. If a battery fire should occur in an electronic device of vehicle and aircraft cabin, it is important to quickly extinguish the fire and cool the batteries to minimize safety risks. Attempts to minimize these risks have been carried out by many researchers but the results have been still unsatisfied. Because most rechargeable batteries are operated on the ion state during charge and discharge of electricity and the combustion of ion state has big difference with normal combustion. Here we focused on the effect of ions including an electron during combustion process. The effects of an ionized fuel on the flame stability and the combustion products were experimentally investigated in the propane jet diffusion flames. The burner used in this experiment consisted of 7.5 mm diameter tube for fuel and the propane was ionized with th ionizer (SUNJE, SPN-11). The results show that toe overall flame stability and shape such as flame length has no significant difference even in the higher ion concentration. However the fuel ionization affects to the pollutant emissions such as NOx and soot. NOx and CO emissions measured in post flame region decreased by fuel ionization, especially high fuel velocity, i.e. high ion density. TGA analysis and morphology of soot by TEM indicates that the fuel ionization makes soot to be matured.