Why Do Lithium Batteries Catch Fire?

It’s not uncommon for lithium batteries to cause fires. In fact, it’s not just electric car batteries, but also the mobile phones and tablets we use, new energy vehicles, etc. These machines can operate normally are inseparable from lithium batteries.

The emergence of lithium batteries has brought many product innovations, but you must not look it down. If there is insufficient safety awareness, improper disposal in use, storage, disposal, etc. Lithium batteries will become a “time bomb”  This is a real case about fire hazard caused by lithium batteries.

“On October 5, 2021, a residential building caught fire, 10 electric vehicles and 1 motorcycle were burned down, and 1 woman and 1 child died unfortunately. After investigation, the cause of the fire was a residential building tenant who purchased lithium batteries for electric bicycles that did not meet safety standards on the Internet and installed them on the electric bicycles. When this lithium battery is charged with an unsuitable charger, the lithium battery explodes out of thermal control, causing a fire.”  Today we will talk about why do lithium batteries catch fires and some standard about Li ion battery safety.

Components and structures are unavoidable to be talked about. According to the different forms of lithium in lithium batteries, lithium batteries can be divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium metal batteries use lithium metal as an electrode to generate electrical energy through corrosion or oxidation of lithium metal.  The most used form of lithium metal batteries is button batteries, which are mainly used in equipment such as computer boards or car keys. A lithium-ion battery is a kind of rechargeable battery, which mainly relies on lithium ions to be embedded and de-embedded back and forth between the positive and negative electrodes to achieve charge and discharge. When charging, the positive electrode of LI+charge is de-embedded, and the negative electrode is embedded in the electrolyte, and the negative electrode is in a lithium-rich state. The opposite is true when discharging.


Firstly, lithium batteries are a key component of electric bicycles.  Even if they are of qualified quality, if lithium battery are used improperly, they may cause fire accidents. For instance, some car owners modify the control systems of batteries and motors to improve speed and range.  This situation will bring certain hidden dangers to the original line, which is also an mportant cause of fire accidents.”


Secondly, using a non-original charger or an original charger with a failed overcharge protection device to charge for too long will cause the battery to heat up, bulge and even cause the battery to catch fire and explode.


In addition, electric bicycles are used for too long will catch fire, too.  If li ion batteries are used and get maintenance improperly, the connection lines in the car are prone to aging and loosening, which can easily lead to leakage and poor contact.  Once shorted, it is easy to ignite wires, seats, joints and surrounding combustibles. When the lithium-ion battery of an electric bicycle is in use, it may also encounter the influence of some external factors, such as impact, puncture, short circuit, etc. , resulting in safety problems, which in extreme cases affect the stability of the battery, and then deflagration occrs.


Generally speaking, the safety problems of lithium-ion batteries are mainly manifested as combustion or even explosion. The root cause of these problems lies in the thermal runaway inside the battery. After the heat of the lithium-ion battery is out of control, the decomposed combustible gas is mixed with the air to form an explosive mixed gas.  When the high-temperature particles ejected by the lithium-ion battery are encountered, deflagration will occur in the local space, resulting in the initial stage of the fire is often accompanied by an explosive sound. Therefore, it is necessary to standardize the use of electric vehicles in life:

use original brand chargers with good performance to charge, and stay away from flammable and explosive items when charging.
 Do not disassemble the charger without authorization, and do not cover the charger shell to ensure ventilation and heat dissipation.
Beware of rain, water, moisture or excessive temperature changes in the charger.
Riding in an area where the water depth exceeds the central axis of the motor on rainy days can easily cause the motor to enter the water, which poses a safety risk.

How harmful are substandard quality and counterfeit products?

According to the General Administration of Market Supervision, in 2022, the General Administration of Market Supervision organized a national supervision and spot check of the quality of electric bicycles and electric bicycle battery products.  A total of 295 batches of products produced by 262 companies were inspected, and 62 batches of products were found to be unqualified, with a spot check failure rate of 21. 0%. The use of substandard electric bicycle batteries is prone to problems such as overcharging, short circuit protection, and flame retardant of the shell, and there are risks of electric shock, fire, and explosion.

The emergence of lithium batteries has brought about many product innovations, but you must not “underestimate” it.  If the safety awareness is insufficient and the use, storage, disposal and other links are not handled properly, lithium batteries may become a “time bomb. “Please do not discard abandoned electric bicycle batteries at will, please contact a professional organization for disposal.

Can Lithium Batteries Catch Fire When Not Use?

No, generally speaking, the probability of lithium battery catching fire is not great. However, compared with old-fashioned nickel-based batteries and batteries of other materials, lithium batteries have a higher chance of catching fire. Comparing from the perspective of the total application of lithium batteries and the amount of fire, in fact, the probability of lithium batteries catching fire is not high.Moreover, in order to avoid the problem of lithium battery catching fire during use, the manufacturer has also set up an additional pressure relief valve, and the shell is made of a strong toughness material.When there is a problem with the internal structure of the lithium battery, the vaporized gas will first be discharged through the pressure relief valve, and the expansion force is usually borne by the shell. This is also the reason why most lithium batteries often appear in drum packs without spontaneous combustion and explosion.

Safety tips: Please pay attention to the safety of using electric bicycle batteries!

Please purchase electric bicycles and their batteries that meet quality standards, and standardize the use of electric bicycles.  If you need to replace the electric bicycle batteries, please choose to purchase from the original manufacturer and do regular maintenance and repair.  If the method is used improperly or fake and shoddy products are purchased, a fire accident may occur.  Once the lithium battery burns, it will quickly ignite the surrounding combustibles, accompanied by explosions, high temperature smoke, and toxic fumes.

For the safety of you and others, please do it:

Standardize the use of electric bicycles and their batteries! Do not bring electric bicycles and their batteries into confined spaces!Prevent it before it happens!Don’t let the “electric donkey” become a “bomb”!