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There is always a risk of explosion at workplaces that store, handle, or produce flammable gases. When flammable gases are mixed with the correct oxygen ratio, an explosion will occur if a heat source is nearby. This can happen, for example, in workplaces that have battery charging stations, as batteries release hydrogen while being charged. Battery charging stations must therefore be monitored by gas detecting systems.
Can batteries explode?
Yes, but the biggest risk is explosions in the storage area as the batteries develop explosive gas which can cause an explosive atmosphere to occur. In batteries, there is constantly a bit of gas developing when water is divided into hydrogen and acid gas, however, development of gas is most powerful when charging.
A mixture of hydrogen and oxygen is called explosive gas, it is very energy-rich and especially explosive in a very large concentration range (4-77 vol%) compared to other gases ex. methane (4.4-16.5% by volume). Since hydrogen gas is lighter than air, it is important to make sure that the battery is not mounted in a place where gas pockets can form above the battery in which the gas can accumulate and reach an explosive concentration. Just a single spark can ignite the gas mixture, which in unfortunate circumstances can result in a powerful explosion.
Gas development occurs mainly in connection with charging, but a certain amount of gas is also formed both during discharge and when the battery is at rest. Therefore, also be aware of the danger of explosion in rooms where batteries are stored.
How do you avoid accidents at work?
This can be done by preventing the gas mixture from developing into an explosive mixture and alerting in case it is about to happen.
One way to prevent hydrogen evolution from reaching explosive concentrations is by venting out of the problem, ie. install permanent ventilation. In connection with the charging process, however, heat is also developed, which means that large amounts of heat energy are sent directly into the blue air unless the excess heat is recycled appropriately.
Another option is to limit the ventilation to what is necessary (demand-controlled ventilation), thereby minimizing both heat loss and electricity for the fans. This can be done by monitoring the gas concentration and only ventilating when necessary. If a gas detector detects that the hydrogen content in the air reaches 10% LEL (Lower Explosive Limit), the ventilation is activated completely automatically. If the ventilation cannot reduce the gas concentration but on the contrary the set limit typically exceeds 25% LEL, you can choose to cut off the power to the chargers, thus almost stopping the hydrogen evolution. Equipment that is not approved for use in EX areas is also typically disconnected.
It is therefore of great importance that the gas detectors have the correct approval for EX areas e.g. EX certificate TÜV 16 ATEX 176482 X. This does not interrupt the power to the gas detectors, and they can continuously continue to measure the concentration of the gas mixture in the room, so you know exactly when it is safe to reconnect the power to the chargers and not EX approved equipment. If you choose to use gas detectors that are not approved for hazardous areas, the power to these is also interrupted and no one therefore knows when the danger of explosion has been eliminated.
At Geopal, we have various gas detectors for explosive areas as well as the necessary knowledge within the area.
Contact us to learn more and get a safe and secure workplace.
