Dafu

UL94 V-0 vs VTM-0 — Which One Do You Need?

This is the #1 confusion in RFQs. Quick rule:

Both are "self-extinguish, no burning drips" per UL94, but VTM-0 is the thin-film variant​ tested on specimens ≤0.25 mm—critical for EV battery spaces where every 0.1 mm counts.

DAFU offers both: transparent V-0 film 0.05–1.5 mm (width 915–1220 mm) for applications needing light transmission, and black V-0 sheet 0.125–2.0 mm (width ≤1200 mm) for opaque, high-shielding use . Halogen-free and halogenated formulations available.

H2: Application 1 — Cell Level (Top/Bottom Pads & Inter-Cell Spacers)

Each cylindrical or prismatic cell gets a PC pad die-cut and back-adhesived​ to the aluminum shell top and bottom. Purpose:

• Electrical isolation​ between cell cap and module metalwork
• Thermal buffer​ — PC's low thermal conductivity slows heat cross-talk
• Anti-abrasion​ for the cell wrap itself

In prismatic stacks, thin VTM-0 PC also goes between adjacent cells​ as a separator that won't propagate flame if one cell vents.

H2: Application 2 — Module Level (CCS Brackets, Side/End Plates)

The CCS (Cell Contact System) integrated busbar assembly often uses PC film vacuum-formed into brackets​ that carry the FPC/signal collection layer .

Where DAFU PC goes in the module:

• CCS suction-formed brackets​ — PC's formability + V-0 rating makes it a go-to vs. ABS (which struggles above 100 °C)
• Side/end plate insulation shims​ — 0.5–1.0 mm black V-0 sheet between busbars and the module aluminum walls
• Voltage sampling wire routing​ — PC's surface resistivity keeps creepage paths clean

Compared with fiberglass/epoxy boards, PC sheet is lighter, doesn't splinter on die-cut, and bends instead of cracking under pack vibration.

H2: Application 3 — PACK Level (Lid Liner, Cell-to-Housing)

Inside the pack enclosure, DAFU PC film/sheet handles two jobs:

1. PACK upper/lower lid insulation​ — liner between the pack shell (often aluminum stamping) and the high-voltage busbars underneath
2. Cell-to-aluminum-housing isolation​ — prismatic packs use PC sheet between the cell stack sideface and the pack casing to block shorts if a cell swells and contacts the wall  

Industry-comparable flame-retardant PC grades in this layer typically hold dielectric strength in the ~20–22 kV/mm range​ and operate long-term at –40 to 120 °C, short-term spikes to 135–150 °C — numbers worth asking DAFU's export team to confirm against your spec.

H2: Application 4 — BESS (Energy Storage Cabinets & Containers)

Stationary storage pushes the same material requirements, just at larger format:

• Inter-cell spacers​ in 280 Ah+ prismatic racks — V-0 PC sheet delays thermal propagation from cell N to N+1  
• Module-to-rack insulation​ — BESS cabinets run 1000–1500 V DC bus; creepage distance rules make PC's volume/surface resistivity attractive
• Internal circuit shielding​ — black V-0 PC for BMS housing, contactor covers, etc.

BESS procurement tends to ask for halogen-free + low-smoke​ formulations (rail/metro spec bleed-through). DAFU's halogen-free black PC line covers this — worth flagging in early RFQ.

H2: DAFU Battery Flame-Retardant PC — Key Data

Sources: DAFU product pages .

H2: FAQ

Q: Do you supply VTM-0 ≤0.25 mm for CCS bracket skins?

A: Yes — DAFU transparent FR PC covers the thin-film window, and black FR sheet can be slit down to thin gauges. Confirm exact VTM-0 certification thickness on the latest UL yellow card with the export team.

Q: Halogen-free or halogenated — which for EV battery?

A: Most Tier-1 battery OEMs now spec halogen-free​ for passenger EV (low-smoke, toxic-gas concerns). Halogenated is still common in industrial/ESS where cost drives.

Q: Can this replace epoxy fiberglass board in PACK lids?

A: In many designs yes — PC sheet is lighter, die-cuts cleanly, and absorbs vibration better. Get DAFU to benchmark CTI/dielectric against your current FR-4 spec.

Q: Lead time for custom slit + die-cut pads?

A: Standard rolls 2–3 weeks; die-cut pad kits with back-adhesive need art-work confirmation — add 1 week.