Efficient and safe battery storage

The future is electric. In the struggle to reduce greenhouse gas emissions, a fundamental "transport and energy revolution" is taking place. In addition to other measures to reduce CO-2, such as traffic limitation and optimising transport routes, vehicles and even aircraft are increasingly being powered by electric motors, hybrid drives or fuel cells. The German government project that there should be at least 15 million electric cars on German roads by 2030. Whether this is realistic remains to be seen. What is clear, however, is that huge quantities of batteries will be needed. In addition to the classic lithium-ion battery, other battery types such as lithium-sulphur batteries, sodium-ion batteries, solid-state batteries, graphene batteries and lithium air batteries will also be used for energy storage in batteries in the future. The safety aspect is particularly important when storing and transporting these batteries. Depending on the chemicals and materials used, battery flammability can be high, so it is particularly important to avoid potential hazards such as leaks, overheating and short circuits.

Fires involving lithium-ion batteries can be extremely explosive despite protective measures taken by the manufacturer. In most cases, water used to extinguish battery fires is then extremely contaminated with chemicals such as heavy metals and corrosive acids and has to be pumped out. Powder extinguishers are not suitable for extinguishing the fire and foam extinguishers are only suitable to a very limited extent. In general, a lot of water must be used to extinguish the fire. One problem is that even a small vehicle fire sometimes requires more water than a fire engine can hold. The batteries must be cooled down so that they no longer ignite themselves.

Other lithium batteries such as lithium-sulphur batteries are less of a fire hazard. The risk of fire is also relatively low for sodium-ion batteries and solid-state batteries. Currently, lithium-ion batteries are mainly used in electric vehicles. They have established themselves as the current dominant battery technology for electric vehicles due to their good performance, high energy density and good rechargeability.
 

When considering storage and transportation, there are 9 classes of dangerous goods, as categorisd by United Nations.  Lithium batteries - in particular lithium metal batteries and lithium ion batteries fall into class 9. The UK doesn’t have specific legislation for the storage of lithium-ion batteries, but the Health & Safety Executive has published guidance here on how to safely handle batteries. German legislation is based on the international UN dangerous goods classes. The German Occupational Health and Safety Act (ArbSchG) contains provisions on health and safety in the workplace. This can affect the storage and handling of batteries in industrial environments in order to protect workers from hazards.

In addition, the EU Battery Regulation (BATT2, 3) is part of the European Green Deal and aims to improve the circular economy, resource utilisation and efficiency as well as the life cycle of rechargeable batteries in terms of climate neutrality and environmental protection. The particular aim of the regulation is to revise the management of battery waste and take measures to protect the environment and human health. This is to be achieved, among other things, by avoiding or minimising the adverse effects of waste generation and management.

The German Insurance Association (GDV) has published the leaflet VdS 3103 for loss prevention when providing lithium batteries in production and storage areas. It reflects key findings from fire tests and provides information on hazards and loss prevention. General safety rules that must be observed include following the manufacturer's instructions, avoiding internal and external short circuits (use of terminal caps, avoidance of mechanical damage) and avoiding overheating. If no automatic extinguishing systems are available, a structural and spatial separation of the stored batteries of at least 2.5 metres from other flammable materials is necessary. Damaged and defective lithium batteries must be removed from storage and production areas immediately and stored at a safe distance or in areas separated by fire protection systems. Storage areas must be monitored with a suitable fire alarm system. Other suitable measures include separation, limiting quantities, storage in fire-resistant separated areas with a safety distance of at least 5 metres and the use of extinguishing systems.

Suitable for the storage of lithium batteries are, for example, safety cabinets in accordance with EN14470, ADR-compliant container and transport systems with a fire protection function and fire protection containers with tested fire resistance. Entire pallet racking systems that are equipped with fire protection grids and a corresponding sprinkler systems are also suitable for storage.. In general, only lithium batteries tested in accordance with UN38.3 should be stored, otherwise a risk assessment is required. Section 38.3 of the UN Recommendations describes the test requirements for the carriage of lithium batteries. These include tests for thermal stability, short-circuit safety, overcharge safety, mechanical tests, shock and vibration tests and other tests to minimise the risk of fire, explosion or other dangerous situations. In general, the batteries should not be charged in the storage area.