Part 1 set out the groundwork: the fire and explosion risks of lithium-ion storage, the regulatory landscape and the role of structural fire protection and certified containers. Now we turn to what goes inside the container and how it all works together when something goes wrong.
Technical fire protection
Technical fire protection is the active counterpart to the structural measures covered in Part 1. It encompasses a range of systems and devices that work together to detect, suppress and continuously monitor fire events inside the container.
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Fire alarm systems play a central role. Smoke and heat detectors in the battery storage area detect and locate fires, enabling rapid response and limiting damage, particularly to the surroundings. The data they generate feeds into central system monitoring, giving operators early sight of developing hazards.
Extinguishing systems
For battery storage, what matters most is the cooling effect. The aim is to slow thermal reactions or prevent the spread from one battery module to the next. Water-based systems such as fine-spray sprinklers fight fires effectively, bind smoke gases and bring ambient temperatures down. Other extinguishing agents may also be suitable, depending on the installation. Systems designed solely for fire suppression, without a sustained cooling function, are not sufficient to control a major battery fire over time and serve only as a supplement. In sensitive water protection areas, measures to retain extinguishing water need to be coordinated with the authorities.
The role of the BMS
Modern storage systems are equipped with a battery management system (BMS) that continuously monitors parameters such as cell temperature and charging and discharging currents. In the event of an incident, the BMS can shut down the storage system automatically to limit further damage. These data should be integrated into central monitoring to enable early response, rather than being siloed inside the battery system itself.
The technical container as a single unit
Rather than planning and installing detection, suppression and ventilation separately, these measures are combined in a compact, pre-installed unit: the technical container. Sensors continuously track smoke, temperature and the release of hazardous gases to identify risks early. Extinguishing systems can be activated automatically to contain fires. Ventilation and extraction systems safely remove heat and gases, while pressure relief devices reduce the risk of explosion.
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By connecting to fire alarm systems and providing interfaces for emergency services, the technical container becomes a complete fire protection system that actively monitors the battery storage and responds rapidly in an emergency. Emergency crews arriving on site have a clear, known point of intervention rather than an improvised response.
Organisational fire protection
Hardware alone is not enough. Organisational fire protection ensures a fast, effective response when an incident occurs. Anyone working near battery storage must receive regular training on the specific hazards and emergency procedures involved. Well-informed staff respond more quickly and correctly, which helps prevent damage and injury.
Routine maintenance of both the battery storage and the fire protection equipment is essential for reliable operation. Fire alarm systems, extinguishing systems and monitoring equipment must be checked and serviced at regular intervals, with maintenance schedules defined by both manufacturers and legal requirements. Relying on the manufacturer's maintenance service allows operators to focus on their core business.
Fire protection infrastructure and emergency planning
A well-designed fire protection infrastructure enables effective and rapid firefighting. This means providing suitable extinguishing agents, clearly marking access points for emergency services and ensuring those access points remain unobstructed.
Effective emergency planning requires reliable notification chains and close coordination with emergency services. Firefighters must have safe, quick access to the storage system, with information on specific fire hazards and the location of extinguishing agents made available in advance. Regular drills with the fire brigade help prepare responders and improve the effectiveness of rescue operations.
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To reduce risk for emergency personnel, firefighters should not have to enter or open the battery room to introduce extinguishing or cooling agents. Suitable openings must be known and clearly labelled. Fire extinguishers should be placed in visible and easily accessible locations for fighting small, still-controllable fires near the storage system before they spread. However, staff must be clearly that hand extinguishers are for external incipient fires and should not be used to fight a storage fire directly.
Detailed emergency plans
Comprehensive emergency plans, regularly reviewed and updated with emergency services, ensure smooth cooperation if an incident occurs. These plans should include the location of the battery storage system, specific fire risks and available extinguishing agents, and should be accessible to emergency services at all times. Ongoing information exchange between the operator and emergency services is essential to discuss new developments, potential hazards and improvements.
Alarm systems must be clearly defined and easily accessible. All components of the fire alarm system should be connected to central monitoring, providing a reliable notification chain so that a fire can be detected and reported to a permanently staffed location at any time. Acoustic and visual alarms such as sirens and flashing lights should be installed to alert everyone near the facility.
Technical containers in practice
Denios has been a specialist in hazardous materials storage and handling for nearly 40 years and has in recent years expanded into the safe housing of lithium-ion batteries. In Germany, projects typically require a fire protection certificate under the model building regulation (MBauVorlV), with certified containers generally considered to fulfil the structural fire protection requirement. From transport boxes and charging cabinets to technical containers for battery storage, the company offers a range of solutions across the scale.
For stationary battery storage, Denios provides several concepts. Customers can choose technical containers with integrated battery storage, from compact systems at 80 kWh to large-scale units exceeding 1.6 MWh, or containers designed to house battery technology from other manufacturers, in which case the batteries are not included.
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The walk-in Power Safe technical container features certified fire protection (REI 90/REI 120) and forms its own fire compartment, suitable for indoor and outdoor installation. The Power Store battery storage system consists of two non-walk-in, fire-protected compartments: a technical section housing secondary electronics such as inverters and air conditioning, and a battery section containing the storage technology. This separation reduces the risk of a fire in the technical section spreading to the battery compartment.
Both Power Safe and Power Store come with integrated battery storage. Denios technical containers are modular, configurable and can be individually equipped with safety technology including early fire detection, climate control, extinguishing, ventilation and extraction systems. Customers also benefit from expert advice, project support and ongoing service and maintenance. (Alina Möbius/TF)
Alina Möbius is Sales and Product Manager BESS at Denios SE in Bad Oeynhausen. She specialises in lithium battery safety and stationary battery storage.
