Protection of lithium-ion batteries

Back in 2015, VdS  fire tests with lithium-ion batteries together with the German Insurance Association (GDV). Initial findings on the fire behavior of e-bike batteries were obtained and a research report compiled.

In 2019, a leaflet with information on sprinkler protection for lithium batteries (VdS 3856) was published, which reflected the state of knowledge at the time. Solutions for shelf and block storage were described for the first time, especially for small batteries or devices with batteries (battery scrapers, etc.). For batteries with a high energy content (>50 kWh/storage unit), no concepts could yet  offered.

Various institutions, such as the Karlsruhe Institute of Technology (KIT) or FM, continued their research and recommendations. Both the FM data sheet 7-112 and the technical data sheet VdS CEA 4001 TB003 - Lithium-ion batteries present ways to protect a storage facility with lithium-ion batteries or end products containing lithium-ion batteries with more than one battery. 50 kWh per storage unit. In contrast to the VdS 3856 data sheet, these two classify the lithium-ion batteries according to SOC (State of Charge).

Legend: [1] Min. 2.4 m between openings in the barrier; [2] At the upright max. 30 cm opening in the barrier.

With the data sheet 7-112 (Lithium-Ion Battery Manufacturing and Storage) published in October 2024, FM bundles the requirements for protection against risks with lithium-ion batteries. However, the focus is not only on their storage, but also on the protection of the production process. In addition to the requirements for extinguishing systems, the data sheet The situation also describes structural and organizational measures, such as the separation of production areas steps or the shutdown of ventilation systems in the event of a fire.

The block storage of lithium-ion batteries with an SOC of max. 60 % is possible up to a storage height of 4.50 m. The ceiling height is limited to 12 m. The sprinkler system must be designed according to data sheet 8-9 depending on the packaging used. A clear strip of 3 m must be kept free from storage blocks or other combustible material.

Storage as a "low-piled substance" in plastic containers up to 20 m² storage area and a maximum storage height of 1.80 m is possible with surrounding free strips of 3 m. However, the SOC must less than or equal to 60 %. The design parameters for various ceiling heights and sprinkler types are summarized in a table. 

Rack storage with ceiling sprinklers only is possible up to an SOC of 60 %. The storage height is limited to 4.50 m or 3 levels and the ceiling height to 12 m.

If the maximum ceiling height of 12 m or the maximum SOC of 60 % is to be exceeded, shelf sprinklers must be provided. To limit the spread of fire in the racking, horizontal barriers must be installed above each level and vertical barriers at the rack uprights or after a maximum of 1.80 m. The operating time of the system is two hours. Only end products containing lithium-ion batteries with an SOC of less than 60 % may be stored in automated small parts warehouses. Concentrated storage of lithium-ion batteries in automated small parts warehouses is not possible.

The Technical Bulletin VdS CEA 4001 TB003 is a translation of the Technical Bulletin CEA 4001-TB- 003-LI-ION Batteries from Insurance Europe, which was published in 2022. The changes made VdS are marked with square brackets in this bulletin. As there are some errors in the Technical Bulletin, the corrected and supplemented VdS version should always be used. Whether special sprinkler protection is required for the storage of lithium-ion batteries or goods containing lithium-ion batteries is first differentiated in a table. For example, end products that contain lithium-ion batteries with a maximum of 1 kWh and whose SOC is a maximum of 60 % are classified in HHS 3 or in the classification based on the plastic contentwhichever is higher.

A limited quantity of 2 m³ lithium-ion batteries incl. packaging per effective area can also be classified as HHS 3 if they are packed in cardboard boxes and the SOC  max. 60 %. If only ceiling protection is provided, the water application rate must be at least 12.5 mm/min over an effective area of 260 m². Shelf sprinklers are installed in this case in accordance with section 11.5 of VdS CEA 4001 in accorcance with HS 3.

As soon as the storage exceeds the limited volume of 2 m3 per effective area or the lithium-ion batteries are not packed in cardboard packaging, the sprinkler system must be designed in accordance with Table 3.a of this data sheet. It specifies the sprinkler type, the water coverage and the size of the effective area for storage type ST1 up to a maximum storage height of 1.50 m and a ceiling height of 12.20 m and for storage type ST4 up to a maximum ceiling height of 15 m and storage up to 1 m below the ceiling sprinklers. Shelf sprinklers must be provided for storage in shelves. The two different variants for cartoned and non-cartoned lithium-ion batteries are  in Figures 1 and 2.

A design with ESFR sprinklers for storage types ST1, ST2, ST3 and ST4 up to a maximum storage height of 4.60 m and a maximum ceiling height of 12.20 m is also available. The nominal capacity of each individual lithium-ion battery must not exceed 50 kWh and the SOC must not exceed 60 %. The maximum partial storage areas must be provided in accordance with Table 5.02 of VdS CEA 4001. In the case of ESFR concepts, the special boundary conditions in accordance with VdS CEA 4001, Annex L, e.g. the need for shafts, must also be taken into account.

Only end products containing lithium-ion batteries with a maximum of 1 kWh per item and a maximum SOC of may be stored in automated small parts warehouses. Concentrated storage of lithium-ion batteries in automated small parts warehouses is not possible even if this data sheet is useddesign with ESFR sprinklers for storage types ST1, ST2, ST3 and ST4 up to a maximum storage height of 4.60 m and a maximum ceiling height of 12.20 m is also available. The nominal capacity of each individual lithium-ion battery must not exceed 50 kWh and the SOC must not exceed 60 %. The maximum partial storage areas must be provided in accordance with Table 5.02 of VdS CEA 4001. In the case of ESFR concepts, the special boundary conditions in accordance with VdS CEA 4001, Annex L, e.g. the need for shafts, must also be taken into account.

In addition to the information on the design of the sprinkler systems, the technical information sheet lists organizational measures that must be taken in close coordination with the local fire department and the leading fire service insurer. In particular, the detection of conspicuous batteries, their removal from the storage area, the accessibility of the fire location for manual firefighting and the removal of thermally runaway batteries from the storage area under the influence of the sprinkler system should be addressed. Information on general safety rules for handling lithium-ion batteries can be found in GDV publication VdS 3103. In addition to the information on the design of the sprinkler systems, the technical information sheet lists organizational measures that must be taken in close coordination with the local fire department and the leading fire service.

In the VdS 3856 leaflet, the batteries are classified into three "hazard levels" depending on their energy content, from "Low ⇒ less than 1 kWh/storage unit" to "High ⇒ greater than 50 kWh/storage unit", as shown in Table 1. The classification and the resulting requirements are independent of the state of charge of the batteries. The protection concepts for storage apply to lithium batteries.

Ion batteries or devices containing them up to an energy content of 50 kWh/storage unit and if they are in pre-wettable packaging. The storage of traction batteries for automobiles is not permitted with these protection concepts. For devices with lithium-ion batteries, both storage on shelves and in blocks is possible.

Sprinkler protection must be provided on each shelf level for rack storage and the design must be carried out in accordance with VdS CEA 4001 Section K.7.1 (Table K.7-1, Category IV). The devices with lithium-ion batteries that are stored in the block are classified in HHS4+ K.7 and protected accordingly in accordance with VdS CEA 4001. Concentrated battery storage in the rack is possible with a design in accordance with VdS CEA 4001 Section 11.5+ K.7 (Cat. IV) and sprinkler protection on each rack level.

In addition, horizontal sheet metal barriers are provided above each sprinkler Level according to VdS CEA 4001 section 11.6.2.5.2 and to install face sprinklers in each cross shaft in addition to the sprinklers in the center shaft. Block storage of lithium-ion batteries is possible up to a partial storage area of 20 m2with circumferential free strips of 2.40 m. The maximum storage height is 1.50 m and the maximum ceiling height is 12 m.

Table 2 summarizes an overview of the storage options and restrictions of the individual data/information sheets. In view of the steadily growing number of lithium-ion batteries that will be stored in the future, the use of modern sprinkler systems is not only an essential step towards protecting storage facilities, but also a forward-looking contribution to safety in a world that increasingly characterized by the energy transition and electromobility.