Flame retardant lightweight composite sheet (Under development)

Mobility

Fire resistance, flame retardant, noncombustible

Recyclable thermoplastic sheet

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Flame retardant lightweight composite sheet

-Challenge- Thermal runaway countermeasures, improved cruising range

While lithium-ion batteries (LiBs) in electric vehicles (EVs) generate high-output energy, they contain a combustible electrolyte that can cause thermal runaway with malfunction or heavy impact. Currently, steel or aluminum covers which combined with inorganic sheets are used on LiBs to prevent heat and flames from entering the vehicle in the event of a fire, but aluminum adds significant weight, which affects the travel distance of EVs. In order to improve the travel distance of EVs in the future, LiBs must have a higher capacity, reduce weight while maintaining safety.

-Solution- Flame-retardant, flame-blocking, heat-insulating thermoplastic resin sheet

To address these issues, SEKISUI has developed a thermoplastic sheet with triple performances of fire retardant, flame shielding, thermal insulation. The weight can also be reduced by up to 61% compared to aluminum.

-Technology- Technical information

Technical overview

Flame-retardant, flame-blocking　Two characteristics to prevent vehicle fire

Non-flammable

Self-extinguishing,
No ignition and No deformation

Non-perforated

Strong resistance to fire blast
Impervious to explosive flame

　Heat insulation

Surface ≦ 300℃

Vehicle fire prevention
No damage from spontaneous ignition of surrounding parts

　Light weight

Max 61% weight reduction
No insulation and adhesives required

Technical details

Flame-retardant,
flame-blocking

Characteristic 01

Non-flammable resin
without flame retardants

Burning test

[Test condition] Apply the flame torch to the developed material for 30 seconds

Burn the material for 30 seconds

The material did not catch fire

No ignition and deformation

Surface resin carbonizes and expands

Inner surface remains unchanged

Characteristic 02

Flame-shielding 3-layer sheet

Structure

How it functions

1．Bottom layer receives LiB ignition ( Flame, active material attack )
2．Middle layer expands and solidifies
3．Top layer maintains its strength even after contact with flame

Cell runaway test

[Test condition]
Verification by placing an actual NMC811/90Ah cell in a casing that imitates a pack, placing a sample between two perforated steel plates, and igniting the LiBs in a thermal runaway.

[Left] Rf. AL
In 2 seconds, the cover was perforated, and the flame penetrated
[Right] SEKISUI Dev. Product
The backside reached 1200°C, but there was no perforation and flame penetration