Lithium-ion batteries place special demands on fire protection during storage. In order to test the effectiveness of the VLITEX battery safe shelf, it was subjected to an intensive fire test at the Fraunhofer Institute. The test was based on the VDMA recommendation 24994_3555925-1 for fire-resistant storage cabinets - adapted to the VLITEX system consisting of shelving and fire protection hood.
It was tested how effectively the Battery Safe Shelf L prevents the spread of fire in the event of a battery thermal runaway and reduces heat exposure and smoke development.
Table of contents
Experimental setup in detail
The battery safe shelf L was fitted with the following batteries on the middle shelf:
- Two e-bike batteries with 857 Wh each (NMC round cells)
- Four tool batteries with 144 Wh each
- All batteries were fully charged (100 %)
Figure 1: Battery test setup
Figure 2: Test setup for battery-safe shelf L
An e-bike battery was specifically prepared to induce a thermal runaway: Two cartridge heaters were installed to deliberately overheat the system. The following sensors were used to collect data:
- Pressure sensor: at a distance of 10 cm from the battery (later destroyed by overpressure)
- Temperature sensors (type K):
- Four pieces in the immediate vicinity of the batteries
- Two sensors inside the prepared battery
- One above and one below the hood
- One each on the front and rear outer shelf wall
- One each at a distance of 10 cm and 50 cm from the outer shelf wall
Procedure of the experiment
After switching on the heating elements, the thermal runaway started after just 24 seconds - initially in individual cells of the prepared e-bike battery. In the following three minutes, further reactions occurred within the battery:
- Temperature rise in the interior up to 660°C
- Selective temperatures above 1,380°C within the affected battery
- Maximum temperature on the hood surface: only 130 °C
- Maximum temperature at a distance of 10 cm from the hood: 96 °C
- Maximum temperature at a distance of 50 cm from the hood: 21 °C
After 11.5 minutes, the smoke was completely extinguished.
Figure 3: Temperature curve diagram
Results and evaluation
The results impressively demonstrate the effectiveness of the VLITEX Akku-Safe shelving system:
- Effective limitation of the source of the fire: The hood is undamaged on the outside. Clear traces of soot are visible on the inside
- Heat protection fulfilled: Measured outside wall temperature maximum 130 °C, at a distance of 50 cm even only 21 °C
- Overpressure absorption passed: The hood withstood a brief build-up of internal pressure of around 0.2 bar - the pressure sensor was destroyed by the force
The unprepared batteries are not propagated. No further batteries were ignited.
Figure 4: The inside of the shelf after the experiment
Figure 5: Undamaged VLITEX fire barrier envelope after testing
Conclusion
The VLITEX Battery Safe Shelf L offers an effective protection system for the safe storage of lithium-ion batteries. The test shows: The combination of flame limitation, temperature and smoke reduction as well as burst protection meets the highest requirements for the storage of lithium-ion batteries.
The VLITEX Battery Safe Shelf L thus complements the portfolio of practical and certified textile fire protection solutions - for more safety in everyday life with lithium-ion batteries.
VLITEX - Smart Fire Protection Made From High-Tech Technical Textiles
