A pressure relief vent for a sealed battery enclosure. It breathes continuously so the box stays at atmospheric pressure as the pack heats and cools, keeps water and dust out while it does so, and blows open if the pressure inside ever rises sharply. Any sealed box holding cells needs one.
The everyday job is breathing. A pack warms in use and cools overnight, and the air inside expands and contracts with it. With no vent, that swing has to go somewhere: it works air past your seals until they leak, or it bows the lid. The membrane in this valve passes air both ways while blocking liquid water, so the enclosure equalises without ever being open to the weather. At 10 kPa it flows 8 litres a minute or better, which is far more than thermal breathing ever asks of it.
The second job is the one that matters on a bad day. If a cell vents, pressure inside a sealed enclosure rises far faster than any breathing membrane can cope with. Between 20 and 40 kPa the valve is driven fully open and gives the gas a deliberate, known way out. Without that, the enclosure chooses its own weakest point, which is usually a lid seal or a gland, and it does so with no control over where the gas goes.
Fit one valve per 200 litres of enclosure volume. That is the sizing rule for this part. A single large pack box usually needs more than one.
Key specifications
| Manufacturer part | BATPACKPRV |
|---|---|
| Type | Combined breather and pressure relief vent |
| Airflow | 8 litres per minute or better at 10 kPa |
| Burst pressure | 20 to 40 kPa |
| Operating temperature | -40 °C to +125 °C |
| Ingress protection | IP67, holding against 12 kPa water, over 1 metre depth |
| Flame rating | UL94 V-0 |
| Sizing | 1 valve per 200 litres of enclosure volume |
| Weight | 0.11 kg |
Features
- Does two jobs in one part: continuous pressure equalisation, and emergency blow off
- IP67 sealed, so the enclosure breathes without letting water or dust in
- Rated from -40 °C to +125 °C, covering cold starts and a hot pack
- V-0 flame rated, as anything on a battery enclosure should be
- Defined burst range, so the box fails where you decided it would rather than at a seal
Compatibility
For sealed EV battery enclosures, energy storage cabinets and any other sealed box containing cells.
There is a smaller version of this valve for compact enclosures and for cases where you want several smaller vents spread around a large box rather than one big one. Same two jobs, same burst range, less flow each.
Mount it high on the enclosure, on a vertical face where it cannot sit under standing water and where venting gas is directed away from the cabin and from anyone working on the vehicle.
In the box
- 1 x PRV vent blow off valve
Downloads
The product datasheet, the dimensioned drawing and a 3D CAD model in STEP format are in the Documents tab. Use the drawing to check your mounting hole before you cut the enclosure.



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