The whole country is noisy due to the fire of

[ESS fire]

The whole country is noisy due to the fire of electric vehicles, and many experts are giving many opinions on the media. It is envious in a sense to see that electric vehicle fires continue to be news and various measures are discussed. ESS is no longer news even if it's on fire.

There is no institution to organize statistics for ESS fires as well as electric vehicle fires. There is data from the Fire Department, but it is very useless because it does not include the cause or manufacturer's information. It is estimated that 50 cases have occurred so far, but few Chinese batteries have been used, so so far, all of them are ESS fires from three domestic companies.

I got a lot of help because one blogger kept organizing it. Electric cars, ESS, and fire causes are similar, and responses are similar.

The main cause of ESS fire was initially due to over-charging, especially over-discharging. Continuing 100 percent charge and 0 percent discharge promotes dendrite formation and quickly destroys the SEI layer. So, the regulations and recommendations have since changed to 90 percent charge and 5 percent discharge. When comparing lithium-ion batteries that are discharged to 80 percent charge/20 and 100 percent charge/0 percent, most of the latter does not have 300 cycles of life. The former can be used 3000 times. In the former case, increasing the c-rate makes it less than 100 times.

Battery performance drops sharply after two years of daily charging and discharging, and the BMS' performance table does not reflect this or if battery deviations accumulate, it will catch fire. Therefore, we limited the amount of charge and discharge, but it caught fire again after 2022. In other words, the ESS industry concluded that limiting the amount of charge and discharge can delay the time when the problem occurs, but it is difficult to avoid the possibility of fire due to the decrease in battery performance and accumulation of deviation.

I hope that the regulations related to electric vehicles will be set reasonably by reviewing what we have experienced in ESS.