Another Controversy Left by the ESS Second Investigation Committee

Director Moon I-yeon of Korea Electric Power Corporation, head of the ESS fire accident investigation team (right), and co-director Professor Kim Jae-cheol of Soongsil University are announcing the "ESS (Energy Storage System) Fire Accident Investigation Team, Investigation Results of Five Fire Accidents" on the afternoon of the 6th at the Ministry of Trade, Industry and Energy in the Government Complex Sejong, Sejong City.
[Image source=Yonhap News]

[Sejong=Asia Economy Reporter Joo Sang-don] Controversy is intensifying following the announcement of the investigation results by the Energy Storage System (ESS) secondary fire accident investigation team. The team concluded that 4 out of 5 ESS fires that occurred between August and October last year were caused by 'battery abnormalities,' but battery manufacturers are protesting, saying they cannot accept this conclusion.

On the 6th, the investigation team held a briefing at the Government Complex Sejong and pointed to 'battery abnormalities' as the cause of the fires. The team estimated that the causes of ESS fires installed in Yesan, Chungnam (battery manufacturer: LG Chem), Pyeongchang, Gangwon (Samsung SDI), Gunwi, Gyeongbuk (LG Chem), and Gimhae, Gyeongnam (Samsung SDI) were due to battery abnormalities. The remaining site in Hadong, Gyeongnam (LG Chem) was concluded to have caught fire due to external foreign substances contacting the exposed pressurized charging part.

According to this, in the case of the ESS installed in Migok-ri, Gwangsi-myeon, Yesan-gun, Chungnam, where the fire occurred at 7:18 p.m. last August, the ignition point was analyzed to be the battery through system operation records (EMS). The battery at the ignition point collected during the on-site investigation showed traces of melting (material heated and changed to liquid) typical of ignition. The possibility of fire caused by external environmental factors was considered low. Although the electrical resistance, which appears when voltage is applied to an insulator that prevents the passage of electricity or heat, continuously decreased, it remained above the standard value. Also, there was no damage or burning phenomenon in the power conversion system (PCS), and the investigation of common mode voltage (CMV) and leakage current at similar sites led to the judgment that the possibility of fire caused by electrical factors was low.

The ESS fire installed on Cheongoksan-gil, Mitan-myeon, Pyeongchang-gun, Gangwon was also considered to have originated from the battery. Past operation records revealed charging and discharging phenomena exceeding the upper voltage limit during charging and the lower voltage limit during discharging, and it was confirmed that the battery protection function did not operate in these cases.

Samsung SDI and LG Chem immediately refuted the investigation team's results. Samsung SDI-manufactured batteries were used in the ESS sites in Pyeongchang, Gangwon, and Gimhae, Gyeongnam, which were subjects of this investigation. Samsung SDI agreed that the fire started from the battery but stated that the battery was not the ignition source. They also pointed out that the batteries analyzed by the investigation team were not from the sites where the fires occurred but were batteries manufactured at the same time and installed and operated at other sites. If the investigation results were correct, fires should have occurred at similar sites using the same batteries. Regarding the investigation team's claim that the protection device of the Pyeongchang ESS did not operate normally, Samsung SDI explained that the team misinterpreted data from three months before the fire. A Samsung SDI official said, "More than twice as many Samsung SDI batteries are installed overseas than domestically, but there have been no fires. Overseas, companies with over 100 years of know-how like GE or ABB operate ESS." This indirectly indicated that the cause of the fire lies in the operation process rather than a defect in the battery itself.

LG Chem also stated that "the battery is not judged to be the direct cause of the fire." However, LG Chem decided to voluntarily replace all ESS batteries produced at its Nanjing factory in China in 2017 to secure trust in the ESS industry and fulfill social responsibilities.

Since battery manufacturers have expressed that they cannot accept the investigation team's results, controversy over the cause of ESS fires is expected to continue for some time. An industry insider said, "Since the investigation team pointed to the battery, the core of ESS, as the cause of the fire, a contraction of the entire ESS industry is inevitable. Battery manufacturers are placing more weight on equipment and operational issues rather than the battery itself, so a dispute over responsibility among these operators is expected to unfold in the future."

This content was produced with the assistance of AI translation services.