Safety Pressure Equalisation Solutions

Pressure balance elements and pressure balance cable glands with valve function.

Safety Pressure Balance Elements: The Pressure Balance Elemente for Li-ion batteries

The move away from fossil fuels for the generation of electrical energy poses great challenges to our society. One of these challenges is the conversion of the ecologically generated electricity into the respective usable form of energy (motion, heat, potential chemical or corresponding electrical energy). This electricity must be converted and often stored. For this purpose, inverters, rectifiers and battery storage units are needed.

With our safety pressure equalisation products, we at RST offer you the right solution for your application: The Ventilation Safety Device (VSD) as well as the Auto Reversible Safety Device (ARSD) and the Auto Reversible Ventilation Safety Device (ARVSD) have been specially designed for battery systems and Li-ion batteries.


Product documents for download:

  • Product cards:

  • Drawings:

  • Assembly instructions:

  • Flyer ARSD SNAP:

  • Test report Ventilation Safety Device (VSD):

State-of-the-art pressure equalization systems with valve function

The energy density processed and stored in converters and accumulators results in high electrical currents, which can cause the systems to overheat or even explode. To avoid this, precautions should be taken for such devices in two respects:

  1. Best possible ventilation to avoid overheating and overpressure
  2. Emergency degassing in the event of explosive overheating and destruction of components (Li-ion cells, capacitors, etc.)

In addition to protecting people and the environment, this also ensures that the systems have a long service life. Many of these systems are designed for mobile use, e.g. e-mobility and railroad technology or for outdoor use. This means that they are sometimes exposed to harsh environmental and operating conditions. In addition to a high degree of protection (IP), the focus is on a high energy density, and mobile systems also require the lowest possible weight.

Costs and the demand for low weight prevent battery storage systems, inverters or rectifiers from being designed to be extremely stable in accordance with explosion protection requirements. Our safety pressure compensation elements therefore provide a remedy.

During normal operation of the system, they guarantee a high degree of protection of up to IP66/68/69K (details can be found in the documentation).

With the VSD, an integrated PTFE diaphragm ensures the appropriate pressure equalization even with the smallest pressure differences. If the pressure rises gradually or abruptly, the VSD opens and thus enables emergency degassing. The ARSD is not equipped with a diaphragm, but emergency degassing takes place in the same way as with the VSD. In addition, the ARSD has a valve function: it is reversible and therefore closes automatically after emergency degassing.

VSD + ARSD = ARVSD Auto Reversible Ventilation Safety Device:

The ARVSD combines the advantages of the VSD and the ARSD. Equipped with a diaphragm, it ensures pressure equalization at the slightest differences, opens at high pressure and closes again automatically when the pressure decreases.


  • Prevention of condensation
  • Prevention of a damaging explosion of the (battery) housing
  • High protection class
  • Vibration-tested in accordance with ISO 16750 "Road Vehicles, Part 3: Mechanical Loads"
  • Maintenance-free

More pressure equalization solutions from RST

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Why should I choose RST?

As a family business, we have been successfully developing, manufacturing and distributing components for electrotechnical applications for 35 years. We asked our colleagues as well as our long-standing sales partner and supplier why they choose RST. We have compiled the answers in a video.

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