Whether in e-bikes, cell phones or cordless screwdrivers - lithium-ion batteries are creating new possibilities as mobile energy storage devices. Thanks to their particularly high energy density, they offer not only flexible use but also a long service life. However, they also pose specific fire hazards that pose challenges for safety and for system-related fire protection.

Attention must be paid to handling and storage along the entire value chain of lithium-ion batteries. Special storage conditions should be observed right from the start of a lithium-ion battery's life cycle, as a battery fire accompanied by bursting, release of corrosive, flammable and toxic substances as well as heat development can lead to a major chain reaction.

Escaping gases are highly flammable and can be ignited by sparks or hot surfaces, which can lead to the formation of large jet flames. With or without flame formation, enough heat is released to exceed the critical temperature for thermal runaway in neighbouring cells. Depending on the cell chemistry, this can start in the range of 80°C to 100°C. As a result, the fire can quickly spread to other modules and products with a battery system. Suitable protective measures must be taken when storing battery systems in high-bay warehouses.

Are lithium-ion batteries substances with an increased fire risk? The incidence of fire in lithium-ion battery storage and disposal facilities suggests the answer "yes". However, there is no substance-specific quantity limit. Storage with REX protective textiles with steel wire reinforcement can limit the fire load in terms of area and quantity. Adjacent rooms can be separated by the REX fire protection curtain. There are some storage systems that already work with protective covers per pallet. This is where the REX fire limiting blanket is used to make up the fire protection cover.

In addition to storage in fire-resistant partitioned areas or with generously selected safety distances, storage systems designed to be as fire-resistant as possible can lead to successful storage concepts for policyholders. Insurance companies also advise insulating storage rooms and fitting them with appropriate fire protection equipment.

Storage can take place in various locations, including production, logistics, recycling, and disposal facilities. As batteries can ignite spontaneously, the mere presence of batteries in a room poses a fire risk. The higher the storage quantity and storage density and the larger and more powerful the batteries are, the higher the risk. Although the state of charge (SOC) is usually low (below 30%) durnig storage, it is higher than 10% and therefore contributes to the risk of fire. The batteries often do not have a battery management system during storage and if they do, this is not activated during storage. Due to the lightweight packaging (cardboard, plastic, etc.), heat radiation can spread quickly, and the entire warehouse can catch fire in a very short time.

With REX textile systems, the fire cannot be prevented, but it can be made controllable. In the event of a fire, the delivery obligation is seen as a major problem, in addition to the fire event, which causes companies a great deal of damage. The damage caused by the fire is a minor factor in this case. A building whose use involves the storage of substances with an increased fire risk, such as lithium-ion batteries, is a so-called special building under building law. Building insurance companies have already formulated initial requirements.

There are currently only a few known studies on firefighting in a warehouse containing lithium-ion batteries as semi-finished or finished products.

People rely on REX technical textiles every day. In the form of personal protective equipment, the technical textiles protect their wearers from thermal exposure and metal splashes. Whether heat protection coats or protective gloves, REX ensures safety at work.

Many of REX's textile products made of para-aramid or para-aramid blended with Preox, PBI® and/or viscose are certified to OEKO-TEX® Standard 100. The certified textiles can be customized and adapted to the complex requirements of personal protective equipment by means of functional coatings and laminations. In cooperation with external testing institutes, we test our products in accordance with EN ISO 11612:2015 for protective clothing against heat and flames. Thanks to the special coating with aluminium or polyester films, we achieve classification up to the highest class C4 in the area of radiant heat. The protective clothing made from our technical textiles is used in foundries and reliably protects the wearer from radiant heat. Our technical textiles are also used as gloves in final processing in the food industry.

People are not the only ones who need safe and robust heat protection. Machines also need to be effectively insulated from high temperatures in their environment. REX's technical textiles division supplies application and customer-specific fabrics for textile protective covers. To protect machines or machine parts with lower temperature resistance from radiant heat, metal splashes and sparks, heat protection fabrics from REX are used as textile protective covers. The fabric used to protect the machines or pipes usually consists of a flame-retardant, non-melting and tear-resistant fabric with an appropriate coating or lamination. Only high-quality materials are used to manufacture these special fabrics, which ensure a reliable protective cover for the machine. Customized textile protective covers, e.g. on industrial robots, can significantly reduce or even prevent damage and high cleaning or replacement part costs.

REX offers manufacturers of smoke barriers, fire barriers and other fire protection systems extremely light, flexible and thin textile fabrics that can be designed for customers according to the required protection target. We guarantee the protection target EW60, i.e. a room closure with limitation of radiation penetration for 60 minutes, as our minimum requirement. Overall, the high-performance textile was able to withstand a 90-minute fire load installed on a 3x4m oven.

Our fabric sets new standards with its special coating in combination with an aluminum foil. With a fire resistance up to 900°C and an extremely high heat reflection of > 90 % we confirm a reduced heat transfer. After a 60-minute flame exposure, a temperature difference of more than 800°C can be measured. Furthermore, the single-layer special fabric convinces through an extremely light and thin construction of < 1 mm. Our REX fire curtain also ensures high durability by guaranteeing protection of the overall composite with a high degree of residual flexibility.

• Fire resistance test according to EN 1634-1/ classification according to EN 13501-2
• Protection target EW60 and more
• Single layer construction < 1 mm
• Extreme heat reflection > 90 %
• Extremely lightweight
  
  

The importance of electric vehicles and other storage systems is increasing rapidly. The growing demand for lithium-ion batteries calls for new fire protection concepts. Although battery fires in electric vehicles, for example, do not occur statistically more frequently than fires in vehicles with combustion engines, they are more difficult to extinguish. In the event of a short circuit in a battery cell, smoke development or in the event of a fire, vehicle owners or emergency services must be able to act quickly to protect people and the environment.

The REX protective textile in the form of a blanket, which can be placed over the smoking or burning vehicle, minimizes the supply of oxygen from the environment, thus containing the fire and reducing the temperature of the battery to prevent it from overheating. The oxygen required for the fire, which fuels the reaction, is nevertheless produced by the battery itself.

In the event of a burning battery, which can only be contained by adding water, the fire blanket mainly serves to protect the surrounding area. This is a particular advantage in parking garages, underground garages, ferries, etc. where vehicles are parked close together. By containing the fire with the fire blanket, the flames are prevented from spreading to surrounding vehicles or objects and thus not cause any major damage. In addition, the smoke development is minimized by the protective blanket and thus protects people in the vicinity from the toxic gases produced by the fire. Studies show that fire blankets greatly limit the flying away of particles and thus prevent or slow down the spread of fire. Furthermore, research shows that the spread of the battery fire to other areas of the vehicle is greatly reduced with the help of suitable blankets. The blanket can also ensure that the fire is prevented from flaring up again during transportation. In addition to the advantages mentioned, the use of a blanket can greatly reduce water consumption during extinguishing.

Through intensive research and comparative studies of different coatings and finishes, which are sold as solutions by some manufacturers, among others, an innovative coating has proven to be particularly effective. The high-performance coating forms a superficial protective layer when exposed to high temperatures (>250°C) and remains extremely flexible even after exposure to flames. Comparable products become dry and cause the textile to break.

• For durable applications at high temperatures >900°C
• Flexible and supple with low smoke development after exposure to temperature
• Reflective properties increase the heat resistance of the carrier fabric
• Not electrically conductive
• Glass fibers are protected against embrittlement for longer period
• Conventional coatings up to 260°C resistance lead more frequent to break

In the future, batteries that store energy in e-cars, e-bikes, smartphones, or the home will have to be
enclosed in such a way that the environment is not damaged in the event of an impact.
In the special composition of selected self-extinguishing high-performance textiles, which have been
specially developed for this heat protection application, in combination with a high-temperature resistant reflective coating system, we have succeeded in achieving a high level of safety and heat reduction on the battery cell carrier.
Our REX Heatshield can be customized and engineered in a variety of designs to suit the appropriate
applications in terms of weight, thickness and drapability. With a material thickness of less than 2 mm, our design for use in e-mobility to protect the occupants, meets the requirements of the automotive industry that has not been achieved in this form till now.

• Battery safety of the future
• Tested according to the high requirements of the automotive industry
• Textile structure < 2mm thickness
• Customized and engineered in a variety of designs to suit the appropriate applications in terms
  of weight, thickness and drapability