The explosion of the power bank it is not a rare event and has precise causes and dynamics. Luca Magagnin, professor of Applied Physical Chemistry at the Politecnico di Milano, explains the functioning and the causes of the anomalies.
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Why can a power bank explode?
“They are external lithium-ion backup batteries, for smartphones, which suffer from high temperatures, resisting up to 80-100 degrees. After that threshold irreversible swelling and explosion phenomena begin to arise”.
Only the external heat favors overheating?
“No. There are also internal causes: from malfunctioning, with low-quality materials that make the batteries less resistant; to incorrect use, such as charging the power bank using non-certified devices that lead to overcharging (overload, ed), by introducing more energy than the battery can accept. Charging management is important: if done incorrectly, over time it tends to degrade the battery, making it more sensitive to the thermal effect. Another reason is the mechanical effect: if the device is deformed or squeezed in the backpack, the electrodes approach forming a dangerous short circuit “.
There are 10 euro portable batteries on the web. What is the right cost to avoid risks?
“The cost is always linked to the energy capacity. Ten euros for a 20-30 thousand milliamper hour (mAh) power bank is too little. Low cost usually means low quality, and this increases the ease of problems in use. battery quality leads them to not hold the charge after a very short time “.
How do you check that the product is up to standard?
“There are certification marks on the product and in the technical data sheets there are specifications on use and temperatures”.
If you have other non-original or damaged devices (such as USB cables or power plugs), is there a chance of an explosion?
“Yes, all these elements, if not compatible, make the battery work in less than optimal conditions. An example are car cigarette lighters: the cheapest ones damage the battery of mobile phones after a few uses because they do not control the incoming energy. The more expensive ones, instead, they do and it is fundamental “.
What advice does it give for conservation and prevention?
“Use certified devices, compatible with the other instruments in possession, do not mechanically stress the battery, do not subject it to heat sources. This way the power bank will last longer and will not have problems of advanced degradation”.
Is it necessary to buy a power bank of the same brand as the smartphone, or is each product universal?
“No, the important thing is that they are guaranteed and official products”.
Physically, what are the risks if a power bank explodes in the vicinity of the body?
“It is very dangerous to health. The more energy they contain, the stronger the explosion. Flames, noxious gases and detonation: even just seeing it is risky.”