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Lithium-ion batteries have become an indispensable part of our everyday lives. They can now be found almost everywhere. In smartphones, notebooks, e-cigarettes, e-bikes, gardening tools, tools and also in the automotive sector.

Due to the ever-increasing prevalence of these batteries, fires are of course becoming more frequent. And when a lithium-ion battery starts to burn, you have a problem. A new problem that did not exist before with conventional batteries.

The storage, processing and operation of lithium-ion batteries always harbours dangers that must be considered on a very individual basis. In any case, a corresponding risk assessment must be made for commercial operators. In a private environment, of course, such a risk analysis is not necessary, but if a few precautions are taken, the risk of fire can be significantly reduced. This applies to both new and old and/or defective batteries.

Lithium Batteries Types

Rechargeable batteries / batteries with low power

Batteries (primary cells) with low power, and not rechargeable, are mainly used for computers, consumer electronics, etc.. Button cells" also belong to this category.
Ready-made, rechargeable lithium-ion batteries are installed in smartphones and also belong to the class of low-power batteries.

Batteries with medium power

Lithium batteries (battery packs with several secondary cells) of medium power are used, for example, in e-bikes, gardening tools and tools. The individual cells used are combined into packs of any size, up to battery packs with high power.

Batteries with high power

High-power lithium batteries are found, for example, in motor vehicles. Due to the high voltages and currents, as well as the size of these batteries, extinguishing systems specially adapted to the situation are required.

Storage and handling of lithium-ion batteries

In the commercial sector, the provision and storage of lithium batteries always requires a risk assessment and thus an individual look at each case. Sprinkler and water spray extinguishing systems to fight incipient fires are neither sensible nor economical for many operators (tool shops, bicycle shops, etc.). Depending on the quantities stored, solutions with portable and/or mobile fire extinguishers are therefore practicable. In principle, the so-called STOP principle should be applied in the risk assessment.

The following applies in principle and also in the private environment:

• Store batteries that are not needed, e.g. tool batteries, in a dry place at room temperature.
• Do not leave batteries in the charger. Remove the battery from the charger after charging.
• Never use damaged batteries. Defective batteries can be recognised by deformations of the housing, excessive heating beyond the normal level. Batteries that no longer provide the usual performance are also defective and should not be used any longer.
• Only use suitable chargers. Unsuitable or defective chargers can damage the battery.

After use - Disposal of lithium-ion batteries

Lithium-ion batteries must be disposed of properly.
Before taking the battery to a collection point, tape the terminals with sturdy adhesive tape to prevent short circuits.

Causes of fire - why do lithium-ion batteries burn?

In principle, modern lithium batteries are just as safe as other types of batteries, provided that the manufacturing standards are observed and they are handled properly. If one follows up reports of lithium battery fires a little further, it usually turns out that the batteries concerned were either mechanically damaged (e.g. by falling) or thermally overloaded (by overloading the device). Defective or unsuitable chargers during the charging process have also been the cause of battery fires.

As a rule, the actual battery cells that pose the problem are not directly visible. They are more or less well packaged in smartphones, notebooks or, in the case of e-bikes, in plastic housings. This means that the burning battery cell is "protected" from the extinguishing agent by the "packaging", or the other way round, the extinguishing agent does not reach the actual source of the fire.

The fire of a lithium-ion battery usually starts very slowly, the cell heats up inside the battery pack. The intensity increases very quickly, however, and ends in the so-called "thermal runaway" and thus a sudden bursting of the battery cell, in which more or less large stub flames can form.

It is therefore almost impossible to extinguish a burning lithium battery cell. Even the VdS does not speak of extinguishing in a leaflet, but only of "... controlling the effects of fires involving lithium-ion batteries."

Some manufacturers of fire extinguishers or extinguishing agents nevertheless claim that their extinguishing agent can actually extinguish these fires. But even they face the above-mentioned problem that the extinguishing agent does not reach the source of the fire. Therefore, this statement must at least be strongly doubted.

Extinguishing agents

Burning lithium-ion batteries can only be cooled. Of these, the extinguishing agents ABC-, BC- and D-powder as well as carbon dioxide are basically not suitable, as they have no cooling effect whatsoever.
Extensive series of tests have come to the conclusion that water with cooling additives is best suited to cool neighbouring cells that have not yet caught fire. This can prevent a chain reaction in which neighbouring cells are ignited. The affected cell can thus burn down in a controlled manner.