Battery overcharge leads to explosion
According to the police, the major fire in Steckborn on December 21, 2015, was probably caused by the lithium polymer battery of a model car. Battery experts at Empa have conducted overcharging experiments on such batteries and provide tips on safe handling.
Lithium-polymer batteries, or LiPo batteries for short, are popular among model builders as high-energy power storage devices. However, batteries of this type are also used in smartphones, tablets, cameras and laptops. Should we be afraid now that such a battery apparently caused the major fire in Steckborn, which destroyed six houses in the old town and left 30 people homeless on December 21?
The results of the investigation by the Thurgau cantonal police were announced on January 8, 2016. According to them, a model construction battery hanging on a charger on the second floor of one of the buildings had caused the fire.
Use only original chargers
Empa battery expert Donat Adams emphasizes that LiPo batteries, which are widely used in the millions, are not dangerous if handled correctly. Normally, a suitable charger is supplied with every battery-powered device. "This should be used as much as possible - this ensures that the appropriate charging voltage is used and that the battery is disconnected from the power supply as soon as it is fully charged." There is also no danger with cell phones, tablets and laptops, according to Adams, because they already have the appropriate charging electronics built into the device.
According to Empa, if a battery is connected to a charger that does not switch itself off, the battery can overheat, inflate, emit hot gases and ultimately catch fire. The Empa researchers had deliberately overcharged a commercially available LiPo battery (1300 mAh) weighing about 50 grams. According to the test institute, the explosion of the battery could well have triggered a room fire (see also Video clip). It is therefore recommended to charge LiPo batteries only on non-flammable bases if possible and to monitor them during charging.
