リチウムイオン電池でんちの発火はっか事故じこ 夏なつに多発たはつ ファン付つき作業さぎょう服ふくでも

It has been found through an investigation by NITE National Institute of Technology and Evaluation that fire accidents involving lithium-ion batteries, which are used in items such as mobile batteries, occur more frequently during the summer.

It is believed that this is due to batteries being exposed to high temperatures, and NITE is urging people not to leave products in places where they are exposed to direct sunlight.

In recent years, those clothes that have become increasingly popular as a measure against heatstroke for people working outdoors in severe heat can also pose a risk of catching fire if not used properly.

*In the latter part of the article, you can watch a video on how to deal with abnormalities found in batteries using lithium-ion cells.

Lithium-ion batteries are used in a variety of rechargeable products such as mobile batteries, smartphones, and computers, but accidents such as fires are increasing every year.

The number of accidents reported to NITE in 2024 was 492, which is 77 more than the previous year and the highest ever recorded.

In the past five years up to last year, a total of 1,860 accidents have been reported, and about 85% of these have led to fires.

When we looked into this by month, August had the highest number with 228 cases, followed by July with 212 cases and June with 201 cases, showing that incidents were most frequent during the summer when temperatures are high.

It has been confirmed that there have been accidents where a mobile battery left in a cars driver seat caught fire, and where a portable fan caught fire while charging.

According to NITE, lithium-ion batteries are susceptible to heat and impact, so exposure to high temperatures can cause the internal temperature of the battery to rise, increasing the risk of fire.

For this reason, NITE is urging people to be careful when using these products, such as not leaving them in places exposed to direct sunlight or inside cars, and not subjecting them to strong impacts.

In the five years up to last year, mobile batteries had the highest number of accidents. NITE announced the number of accidents by product over the past five years up to last year.

According to the report, the most common accidents involved mobile batteries, with 361 cases 19

4% and next, electric assist bicycles with 202 cases 10

9%, ▽Rechargeable power tools: 171 cases 9

2%, ▽ rechargeable vacuum cleaners: 157 cases 8

4%, ▽laptops: 134 cases 7

2%, ▽Portable power sources: 110 cases 5

9%, ▽Smartphones: 102 cases 5

It is 5%.

Reflecting the fact that lithium-ion batteries are used in a wide variety of products, others accounts for 623 cases, making up one-third of the total.

Of these, 40 cases involved rechargeable portable fans, and work clothes with small fans attached are also included in the other category.

With the increasing severity of summer heat due to global warming, work clothes equipped with small fans—garnering attention and seeing wider use as a countermeasure against heatstroke—have also experienced incidents such as lithium-ion batteries catching fire.

According to the Fire and Disaster Management Agency of the Ministry of Internal Affairs and Communications, although there are no comprehensive statistics, since 2018 there have been at least a few fires each year nationwide caused by work clothes with built-in fans.

Also, when checking the Accident Information Data Bank System operated by the Consumer Affairs Agency and others to share information about accidents that occur close to home, there have been at least 20 reported cases since 2021 of incidents such as battery overheating or ignition in fan-equipped work clothes.

Of these, in a fire last June in Aichi Prefecture where a house was completely destroyed after a fan-equipped garment caught fire near its battery while charging, one elderly woman died.

On social media: Work clothes caught fire — In some cases, improper handling was the cause. On social media, there have been posts such as The battery of a fan-equipped work suit swelled up and exploded while charging, or The battery of a fan-equipped work suit wasnt working well, so I got a replacement, but that one caught fire. There was even a post saying, While working in a fan-equipped suit, the battery caught fire and I burned my back.

On the other hand, there were also cases caused by improper handling, such as getting angry and throwing a fan-equipped work uniform, which caused the battery to explode.

Consultations at consumer service counters are also on the rise. At the Tokyo Metropolitan consumer service center, there have been increasing inquiries regarding fan-equipped workwear, such as Is it safe to wear when the battery part gets hot?

According to the Tokyo Metropolitan Consumer Affairs Center, there were 2 inquiries regarding fan-equipped workwear in fiscal year 2020, 3 in 2021, 6 each in 2022 and 2023, and 12 in 2024.

Junko Takamura, Chief of the Consultation Section, said, These are convenient items that can easily help you cool down, but please understand that they are not ordinary clothes since they have fans and rechargeable batteries. I would like people to be careful about wearing them for long periods and when charging them.

I think many people who work outdoors, such as at construction sites, wear them, but the lithium-ion batteries that power the fans are vulnerable to impact. So if you bump into something while working and the battery receives a shock, it could lead to an accident. Therefore, you need to be careful not to hit the battery area as much as possible.

Some people wear it when they go fishing or camping, but its not very water-resistant, so please be careful not to get the battery wet.

NITE releases experimental video of fire accidents, urging caution. Since lithium-ion batteries are vulnerable to heat and impact, careful handling is necessary. NITE has released an experimental video showing typical cases of fire accidents to raise awareness.

[Portable Fans] In recent years, the number of people using rechargeable portable fans has increased, but caution is necessary as there have been a series of accidents such as battery explosions and fires.

If a strong force is applied, such as from a fall, the internal battery may be damaged even if there is no visible problem. In the experiment video, a handheld fan that continued to be used as is suddenly explodes near the mannequins face.

[Smartphones] With familiar smartphones,

- Cases such as accidentally dropping a device on the floor while trying to attach a charging cable, - Dropping a smartphone from a shirt breast pocket when crouching down to tie shoelaces, - Applying excessive force by falling or sitting down while a device is in the back pocket of pants, - Accidentally bumping a fabric tote bag containing the device and other belongings into a door or similar object, - Or a case where a pet dog chewed on a device left indoors and damaged the battery, are introduced.

[Mobile Batteries, etc.] The most accident-prone mobile batteries, and portable power stations that are becoming increasingly popular as outdoor and disaster preparedness items.

They are calling on people to check recall information based on the product name and model written on the box, as there have been repeated cases of fires caused by people unknowingly charging products that are subject to recall.

Recall information can be checked on NITEs website and other sources.

[Electric Bicycles & Power Tools] Regarding batteries for electric assist bicycles and power tools, non-genuine products sold online as compatible items are cheaper than genuine ones, but there are concerns that their safety measures and quality control are insufficient, leading to a higher risk of fire. In the worst cases, there have been incidents of batteries catching fire while charging. To raise awareness, an experimental video has been released to warn users.

None of the products should be extremely cheap compared to others or have unknown seller contact information, as there is a risk that poor-quality items may be mixed in, so caution is necessary.

Left in a car under the blazing sun... There have also been ongoing incidents where products using lithium-ion batteries are left on dashboards or in trunks of cars under the scorching sun and catch fire, so experimental videos of such cases have also been released.

Why do they catch fire? How can you deal with it? [With video] Lithium-ion batteries are used in various products, but why do they catch fire?

Lithium-ion batteries contain a flammable electrolyte, so as they degrade with continued use, flammable gases may accumulate inside.

At this time, the product may expand, and if a strong impact or pressure is applied to a battery in such a state, causing internal components to break or overcharging to occur, heat may be generated, which can cause the flammable gas accumulated inside to ignite.

NITE also introduces in a video how to deal with abnormalities found in batteries that use lithium-ion cells.

First, if you notice anything unusual, stop charging or using it immediately.

On top of that, if the battery is swollen, you can put it in a metal bucket, close the lid, and secure it with aluminum tape to help prevent the spread of fire even if it ignites.

It means that effective measures can be taken using items found at home, such as metal pots or earthenware pots.

If you attempt to extinguish the fire yourself, pour a large amount of water to put out the flames, submerge it in water as much as possible, and then call the fire department.

However, if you leave it in a car that has become hot and smoke or fire appears, there is a risk that the fire could suddenly grow larger, so it is dangerous to try to handle it yourself. Please move away from the car immediately to ensure your safety, and then report it to the fire department.