Why do electric scooter batteries explode?

Why do electric scooter batteries explode? How can I avoid battery fires?

Electric scooter batteries use lithium-ion batteries, which are also used in phones, laptops and electric cars. They work by moving electrons and lithium ions inside the cell to generate an electric current. Due to their high energy density, many of their components are highly flammable.

Lithium-ion batteries are made up of complex chemicals that can ignite due to various factors. Electric scooter batteries can cause more powerful explosions than phones or laptops because electric scooter batteries are larger. Stricter regulations and safety standards have helped to reduce the risks in phones and laptops, but now electric scooters face similar problems.

What causes explosions?

There are three main causes that can lead to an explosion or fire in scooter batteries:

1. Faulty or faulty electronics: this can be caused by overcharging, over-discharging, incompatibility between the battery and the charger, or by a faulty battery management system (BMS) or a short circuit on the outside of the battery. This can lead to very high electrical currents that exceed safe limits.
2. Mechanical causes: deformation or puncture of the battery by an external object, severe and repeated impact, strong vibration.
3. Thermal causes: this can be caused by an external heat source or by excessive internal temperature caused by overcurrent or short circuit. This can lead to “thermal leakage”, where an uncontrolled chemical reaction starts inside the battery, releasing a lot of heat and flammable gases. Ultimately, this can lead to an explosion.

Electric scooter batteries bought from reputable companies are unlikely to explode if they are treated properly and not modified. The main culprits in battery explosions are damaged, modified or poorly manufactured batteries.

Are Xiaomi scooter batteries safe ?

Xiaomi and Ninebot electric scooter batteries have the market-leading safety record thanks to advanced protection measures. One of the most important elements is the temperature sensors that monitor the battery in real time. If the temperature exceeds safe limits, the system can restrict charging or even driving, protecting the battery from potential damage. In such cases, the scooter’s display can show an error code 39, signalling the need to let the battery cool down.

Unfortunately, many other manufacturers of electric scooters do not install similar safety systems, shifting the safety risk onto the shoulders of users. Particularly worrying are the manufacturers of low-cost scooters, who may not even use insulating materials to separate the battery from the control board, wiring or other components. Such solutions can lead to short circuits or even fires, endangering not only the scooter but also the user.

How pressing is this issue?

According to the National Fire Protection Association, fires caused by electric scooter battery explosions “happen quite regularly and are on the rise”. In New York City, one of the main hubs for electric scooters, the number of fires caused by electric scooters has increased from 30 in 2019. to 220 in 2022. Six people died as a result of fires caused by electric scooter batteries.

Best practices to prevent battery spontaneous combustion

The most important thing you can do to avoid igniting your electric scooter’s battery is to buy an electric scooter or battery from a reputable brand and only use the charger purchased with the electric scooter or that is CE certified. CE certification is a recognised safety standard.

Here are a few more tips to keep your electric scooter safe:

• Disconnect the scooter when it is fully charged. Do not leave it unattended when charging, for example overnight.
• Do not alter or modify the battery mechanically or programmatically.
• Keep the scooter away from external heat sources such as radiators or heating vents.
• Do not store the electric scooter in the bedroom, near flammable materials and, if possible, keep it away from places where it blocks the exit.
• Do not use extension cords for charging as they change the level of electrical resistance.
• If you have an accident, make sure you check the battery for damage.
• Do not charge the battery when it is overheating and do not ride the scooter at temperatures below -20 degrees Celsius.
• If you are not sure of the battery manufacturer, check with your local scooter shop or replace the battery. If the battery overheats, makes a strange smell or noise, or changes shape or colour, move it away from anything that could catch fire and call 112.

What is being done to tackle this problem

Although EU requirements stipulate that all batteries must carry a CE certificate to ensure their safety, the reality is that the Customs Department has limited capacity to check each imported battery. This means that there are no strict controls and consumers are forced to rely on the honesty of the manufacturers and hope that they will not try to save money at the expense of safety, risking their reputation and the welfare of their customers.

In this situation, it is particularly important to choose trusted manufacturers such as Xiaomi or Ninebot, which invest in advanced battery protection technologies and adhere to the highest safety standards. Unfortunately, cheaper, less well-known brands can hide unpleasant surprises, so it is worth checking the specifications and the manufacturer’s reputation before you buy one.