Battery of Modified Electric Bicycles by a Middle Eastern Foreigner Explodes!

It was late at night in late June when an explosion suddenly occurred in a room in a quiet residential area.

The explosion occurred in a room of an apartment building in Higashi Ikebukuro, where several Middle Eastern foreigners were sharing a room. Part of the ceiling had been ripped off, the floor was littered with skeletal chairs and blackened trash, and more than 10 pairs of burnt sneakers were lying on the floor at the entrance, indicating the severity of the explosion.

Several young Middle Eastern expatriates lived in the room. The battery of their electric bicycles suddenly exploded in the middle of the night. They were hard at work for Uber Eats and often fiddled with their bicycles in front of the apartment, but we never thought it would happen. Fortunately, no one was killed and the fire was extinguished quickly, with no damage to the floors above or below.

Fires caused by lithium-ion batteries (LIBs), which are used in electrically power assisted bicycles and mobile batteries, continue to occur. According to the Tokyo Fire Department, there were 141 LIB-related fires that occurred in its jurisdiction in 2009. According to the Tokyo Fire Department, 141 LIB-related fires occurred in its jurisdiction in 2009, an increase of 37 fires from the previous year, and the number is increasing every year.

In ’19, a tragic accident occurred in Aichi Prefecture when a two-story house burned down, killing two people who were sleeping. The possibility of a fire starting from a charging smartphone has been pointed out as the cause of this accident.

Behind the increase in such fires caused by LIBs is the fact that LIBs have become widespread in society and are now installed in a variety of products. In addition, I believe that the easy availability of inexpensive, non-genuine products such as mobile batteries through online shopping has also had a significant impact.

Reference] The Dangers Posed by Lithium Ion Batteries

Why do defective LIBs catch fire in the first place? Mr. Nanae Miyagawa of the National Institute of Technology and Evaluation (NITE) explains.

Roughly speaking, LIBs consist of a positive electrode and negative electrode immersed in a flammable electrolyte, separated by a material called separator. Inexpensive Non-genuine products tend to have lax product safety and quality control compared to genuine products.

If minute foreign substances are introduced during manufacturing or scratches occur during use, the cathode and anode, which are supposed to be separated, may stick together and cause a short circuit. If a short circuit occurs, a chemical reaction occurs inside the product, the temperature rises, the electrolyte becomes a flammable gas, and the spark from the short circuit becomes a source of ignition, causing the product to catch fire. In fact, this is a delicate product.

Particular attention should be paid during charging, a time when the LIB is under heavy load and the effects of foreign substances and scratches are likely to become apparent. About half of the cases that lead to ignition occur during charging,” says Miyagawa.

When using a smartphone in the sweltering heat, it sometimes gets so hot that it makes one feel uneasy. To the untrained eye, this may seem like a dangerous sign, but Miyagawa continues, “LIBs are vulnerable to temperature changes.

LIBs are not sensitive to temperature fluctuations, and are normally recommended to be used in a temperature range of 0 to 40°C (32 to 104°F). More important, however, is to avoid strong shocks. I have the impression that in many cases, some kind of shock triggers the ignition.

For example, a mobile battery is placed in a backpack that is full of luggage, and the user leans on a chair while carrying the backpack. Avoid this type of pressure on the product; forcing the LIB into the product or squeezing it by hand because you cannot fit it into the product properly is also dangerous. Also, to avoid grabbing a defective product, especially when purchasing a non-genuine product, we recommend that you search for the manufacturer and check for accidents that have occurred in the past.”

In order to avoid the worst-case accident as described above, LIBs should be used with care, recognizing that they are delicate products with the possibility of ignition (Miyagawa).