UL94 Flammability Grade & Fire Safety Analysis of QS Antispark Connector Housing Materials

Thermal runaway and local short-circuit fire are the most terrifying safety accidents for lithium battery packs, energy storage containers and electric vehicle power systems. As the key plastic structural part directly installed beside battery cells, the connector shell must possess excellent flame retardant and self-extinguishing capability. Once the plastic shell catches fire and spreads flames, it will aggravate the whole battery cabinet combustion and cause irreversible property loss. UL94 vertical burning test is the most authoritative industry standard to judge plastic fire resistance.

Three core hazards brought by non-flame-retardant connector shells in battery systems:

1. Sustained combustion after being ignited by abnormal arc or thermal runaway high temperature, spreading flame to surrounding wiring and plastic brackets.
2. Producing dense toxic black smoke under high-temperature combustion, blocking equipment internal heat dissipation channels and triggering secondary failures.
3. Melting and dripping burning molten plastic to short-circuit adjacent wiring harnesses and expand the fault scope.
   

All shell raw materials adopted by YOUWEI for QS Antispark connectors undergo strict UL94 flammability certification in advance. We tested modified nylon and reinforced PBT shells separately under UL94 vertical burning standard:

1. Modified Nylon shell: Reaches UL94 V-0 grade, self-extinguishes within 3 seconds after flame source removal, no molten dripping phenomenon, low smoke density. Suitable for low-temperature outdoor open installation scenarios.
2. Reinforced flame-retardant PBT shell: Also UL94 V-0 certified, higher heat distortion temperature (150℃), better anti-smoldering performance, extremely little smoke output during combustion. More recommended for fully sealed battery boxes, enclosed energy storage cabinets and high-temperature charging pile interiors.
   

We also add long-term aging verification for flame retardant additives. After 1000 hours high-temperature accelerated aging test, both nylon and PBT QS shells retain complete V-0 flame retardant performance without attenuation of fire resistance, avoiding safety degradation after years of equipment operation.

Engineers can follow this simple selection rule: Open installation, cold region outdoor devices, frequent disassembly equipment → Modified Nylon UL94 V-0 QS shell; Closed battery pack, high-temperature continuous working environment, indoor densely arranged energy storage clusters → Flame retardant PBT UL94 V-0 QS shell.

We can provide official UL material certification files of QS housing plastics for your product safety audit and third-party testing submission.

If you have any request please contact with my tech team http://www.youweic.com