39 that behaviour continues to pose new challenges for fire departments. In contrast to fires caused by other common causes, fires caused by batteries generate jets of flame. In comparison to more familiar fuels, reactions caused by lithium-ion batteries are difficult to assess due to unpredictable fire behaviour, reaching an all new dimension of danger. If lithium-ion cells are overloaded or exposed to high temperatures, the layer structure of the metal oxides used collapses, resulting in thermal runaway. Exothermic reactions also release high quantities of energy, along with oxygen. High heat causes the electrolyte fluid to evaporate and form a flammable gas. If this gas ignites, the lithium-ion cell catches fire. This chain reaction is essentially impossible to stop with commonly available technologies. The fire can spread from cell to cell inside the battery. Batteries experiencing thermal runaway can cause secondary fires in plastics or cardboard. These can be suppressed with foam, CO2, powder and metal fire extinguishers, however they are very likely to be reignited by burning cells. Rapid evacuation Because of this, storing lithium-ion batteries in a specialised safety storage cabinet like asecos’ ION-LINE models ensures a high level of building safety. These cabinets cannot prevent a defective battery from catching fire, but they can protect the surrounding area and persons nearby. The safety storage cabinets offer not only 90 minutes of fire resistance from the outside to the inside, but from the inside to the outside as well. This means that, if a fire does occur inside the cabinet – for instance due to an overheating battery – the building is protected against flames and the toxic gases emitted for 90 minutes. This provides valuable time for safely evacuating employees and allowing fire department and rescue personnel to initiate further safety measures on site. The cabinet is designed with clearance underneath so that it can be effectively evacuated by the fire department. In case of danger, it can be removed quickly from the building. In addition, in case of a fire, professionals should have access to the inside of the cabinet so that they can decide whether to remove the batteries and thereby interrupt the chain reaction. These safety aspects were pivotal in the Greifswald Fire Department's decision, as Norbert Stawinski says: “asecos delivered the full package. The cabinet is very easy to handle, and it can be moved to a different setup location at any time. The entire safety storage cabinet can also be removed in case of a defective battery. The combination of storage, charging, and the safety aspects won us over!” No downtime Often, charging high-power batteries after a fire department deployment can take 2 to 6 hours, or even longer in individual cases. Factors impacting this time include the battery size, charge current, and charger availability. The best solution for avoiding downtimes are devices with exchangeable batteries. Additional batteries are needed in this case, however devices can be put back into operation in just seconds. Because of this, the Greifswald Fire Department works with multiple exchangeable batteries that are stored in the safety storage cabinet. Norbert Stawinski says: “There are between 50 and 100 batteries of different sizes and power classes at the operating site. There are multiple chargers in the safety storage cabinet itself, which can charge up to 5 batteries at the same time depending on the manufacturer. Fully charged batteries are also stored there. After training or a deployment, used batteries are exchanged for charged ones”. Project summary Company: Greifswald Fire Department Location: Greifswald, Germany Industry: Public service Application: Storage and charging of batteries for rescue equipment
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