As electric vehicles (EVs) are rapidly adopted worldwide, large numbers are now transported by sea on dedicated car carriers. With this trend, concerns are increasing about fires and explosions caused by battery thermal runaway during marine transport, while existing SOC limits before loading remain largely empirical. This study experimentally investigates gas generation and explosion characteristics of EV lithium-ion cells under thermal runaway conditions representative of enclosed vehicle decks. We identify and quantify the main off-gas components and clarify the flammability behavior and explosion limits of key combustible species. The results provide basic data for assessing EV battery accidents at sea and support the development of safer ventilation and gas-management strategies for ships.
Lithium-ion batteries (LIBs) have become a main energy storage device in various applications, such as portable appliances, renewable energy facilities, and electric vehicles. However, the poor thermal stability of LIBs may cause explosion or fire. The thermal runaway is the result of a failure of the separator inside LIB. Damages like tearing, piercing, and collapsing of the separator were simulated in a mechanical, an electrical, and a thermal way, and small discharge pulses of a few mV were detected at the time of separator damages. From the experimental results, this paper provided a method that can identify the separator failure before thermal runaway in the aspect of a potential explosion and fire prevention measures.
Hole explosion behaviors were observed during drilling fine holes with laser beam on the LTCC green bar of 320 ㎛ thick after lamination of green sheets prepared by tape casting of thick film process. The incidence of these hole explosions was inversely proportional to hole sizes. The incidence of hole explosion was 20 % number of hole with the size of 60 ㎛ exploded for the UV radiation, while the explosion did not appear for hole sizes over 100 ㎛. To prevent hole explosion behavior during laser-drilling of fine holes, carbon black powder was added as an additive in the LTCC composition, which has superior thermal durability. As a consequence, hole explosion rate was suppressed to 0.8 % for the hole size of 50 ㎛ green sheet with the carbon black amount of 10 weight % and the laser power of 3 watt. Added carbon is thought to reduce the heat-affected region during laser drilling.
In this paper, we develop a explosion-proof LED lighting (Ex circuit) circuit of Explosion-proofLED Signal Lamp (Ex LSL) to utilize the core module of the explosion-proof Local Control System (ExLCS) for offshore plant applications. And then analyzed its electrical, optical and thermal characteristics. Ex circuit was applied input voltage from AC/DC(12~254) V. In this experiments, stable light-oncharacteristics were confirmed by eyes for the every input voltages with min. 78,462 and max. 517,975cd/m2 of luminance. also Output current and output luminance was made proportional. Because themeasured maximum surface temperature of Ex circuit was 54.23℃ at AC 48 V, Ex circuit was rated withT6 of temperature class. Finally, Ex circuit was shown stable light on characteristics under the?50℃ and60℃ during 12 hours of test period.
For the semiconductor device safety from over current in the digital electronic circuit systemmust be surely designed that it`s surface mount type micro fuse device. In this paper, We has analysedto the fusing character of micro fuse as a function changed thickness of thermosetting ink epoxy. To thechange of thermosetting ink epoxy thickness with in production lot, in the electrically character (fusingtest in the 2 multiple over current and 10 multiple over current, surface temperature test in the 1.25multiple over current) of micro fuse has been tested. According to the electrically character result,changed thickness of thermosetting ink epoxy in designed micro fuse withheld direct effect in both endresistance changes. Also, because high thermal energy in the micro fuse test of over current wasoccurred to effect such as thermal runaway and explosion. Therefore, screen printing process in thedesign of micro fuse using thermosetting ink epoxy is very important for production quality improvement.
Zn wires have been electrically exploded in methanol or distilled water using the pulsed power technologies. The nanopowders produced by the explosions have been observed by using SEM and TEM, and analyzed its phase by using EDS and XRD. The nanopowders produced in distilled water showed ZnO phase only. On the other hands, the nanopowder produced in methanol showed mixed phases with Zn and ZnO. The HR-TEM images of the nanopowders produced in methanol showed that the some particles have been coated with carbon like materials. It is considered that the carbon coatings could be depended on the positions of the particles during the plasma state formed by explosion.
Nickel wires of 0.8 mm in diameter and 80 mm in length were electrically exploded in liquid media such as water, ethyl alcohol. The distribution of particle sizes was broad from a few micrometers to tens of nanometer. It was identified that the particles could be classified according to its sizes by using centrifugal separator. The powder prepared in distilled water showed mainly pure metallic Ni phase although a little oxide phase was observed. The powders prepared in ethyl alcohol showed complicated unknown phases, which is attributed to the compound of carbon in the organic liquid. This unknown phase was turned to pure metallic Ni phase after heat treatment.