The spark that started inside the lithium-ion battery inside the Pangyo SK C&C data center in Gyeonggi-do last weekend spread to a big fire, and it is estimated that the Kakao service has failed, and attention is focused on the specific cause of the spark.



Chemical engineering experts agreed that there are too many reasons why sparks can occur in lithium-ion batteries and that the results of the investigation should be closely watched.



Lithium-ion batteries are secondary batteries that generate electricity by utilizing the chemical reaction of lithium.



Although the price is higher than other batteries, the output power is quite high, so it is mainly used in places that require a lot of power, such as data centers.



Cho Jae-pil, a Distinguished Professor in the Department of Energy and Chemical Engineering at the Ulsan Institute of Science and Technology (UNIST), said, "The battery that can cover the data center is actually only a lithium-ion battery.



Lithium-ion batteries are composed of positive and negative electrodes, a separator that blocks the contact between the two electrodes, and an electrolyte that helps ions move well.



These batteries move lithium ions from the positive electrode to the negative electrode when charged, and return to the positive electrode when discharged, and are repeatedly charged and discharged.



When charged, lithium ions are forced to migrate to the negative electrode and become chemically unstable, especially when fully charged, which is theoretically most unstable.



It is also known that fires from lithium-ion batteries in electric vehicles are more common when the batteries are left in a fully charged state than when they are being charged.



However, experts say the causes and processes of a phenomenon called 'thermal runaway', in which sparks occur inside the cell and lead to a fire, are quite diverse, experts said.



A professor of chemistry at a university in Seoul explained, "There are a lot of backgrounds for thermal runaway."



He explained that an 'internal short' was one cause of a battery fire, but he gave the clue that "it's just one possibility."



'Internal short circuit' refers to a strong chemical reaction that occurs when the anode and cathode react with each other inside the battery cell, causing the electrolyte to burn and the anode and cathode to burn in a chain.



Professor Cho Jae-pil of UNIST said, "In order to know the cause of a fire, it is necessary to analyze the cell, but as the battery cell is burned out in the fire, it becomes impossible to determine the cause. You will need this,” he said.



Prof. Cho said that in 2016, Samsung Electronics collected hundreds of thousands of units and investigated the cause of the successive ignition of the Galaxy Note 7.



Experts point out that lithium-ion batteries are basically vulnerable to heat compared to other batteries such as lead-acid batteries and water-based zinc batteries,



“Lithium itself is a material that generates heat very well, so lithium ion batteries themselves are always at risk,” said Park Chul-min, a professor of new materials research in the Materials Science and Engineering Department at Kumoh University of Technology. We are researching,” he explained.



Woo Jung-je, director of Gwangju Eco-Energy Research Center, Energy Technology Research Institute, said, "As a battery is difficult to turn off once ignited, it is important to design it safely (from the beginning). needs to be supplemented,” he explained.



(Photo = Yonhap News)