What Is a Vent Valve?

Dec 12, 2025

A vent valve is a specialized protective component engineered to regulate air pressure within sealed systems, while simultaneously blocking the ingress of water, dust, and other contaminants. Across modern industries—particularly electric vehicles (EVs), energy storage systems, and battery-powered mobility devices—vent valves serve a critical safety function. They safeguard internal components, boost system stability, and prevent catastrophic failures even in harsh operating environments.

Among the most widely used variants are the IP67 Plastic Vent Valve, Waterproof Plastic Vent Valve, and Corrosion-Resistant Vent Valve, which are integral to EV battery packs, e-bike battery systems, and new energy vehicles. Advanced models such as the EV Battery Explosion-Proof Vent Valve add an extra layer of safety for high-energy battery modules.

What Does a Vent Valve Do?

A vent valve enables controlled airflow between the interior of a sealed enclosure and the external environment, with three core functional objectives:

（1）Pressure Regulation

Temperature variations or internal chemical reactions can trigger pressure fluctuations in battery packs. A vent valve equalizes internal and external pressure, protecting the structural integrity of the housing.

（2）Moisture & Dust Protection

Premium IP67 Plastic Vent Valves utilize hydrophobic membranes to block water, dust, and contaminants while maintaining consistent breathability.

（3）Safety Assurance

Abnormal chemical reactions in EV battery systems may lead to gas accumulation. An Explosion-Proof Vent Valve or EV Battery Explosion-Proof Vent Valve releases built-up pressure in a controlled way, preventing enclosure deformation or explosion.

Why Vent Valves Are Critical for EV Battery Packs & New Energy Vehicles

EV battery packs operate under dynamic, demanding conditions: high current loads, extreme temperatures, constant vibration, and outdoor exposure. Proper ventilation delivers four key benefits:

（1）Enhanced Battery Safety

Lithium batteries produce gas during overcharging, thermal runaway, or aging. A plastic vent valve enables safe gas venting while shielding the pack from external hazards.

（2）Longer Battery Life

Moisture and dust infiltration accelerate component corrosion and reduce insulation performance. A Corrosion-Resistant Vent Valve minimizes internal humidity and contamination, extending battery service life.

（3）Structural Stability

Without proper venting, pressure changes from charging/discharging temperature cycles can deform battery housings.

（4）Compliance With Industry Standards

Explosion-proof venting is a mandatory requirement in most regional safety standards for EVs and mobility systems.

Types of Vent Valves for Battery Applications

Valve Type	Key Use Case
IP67 Plastic Vent Valve	Outdoor battery systems requiring robust waterproof/dustproof protection
Waterproof Plastic Vent Valve	E-bikes, battery boxes, and scooters exposed to rain and water splashes
Corrosion-Resistant Vent Valve	Humid, salt-spray, or chemically aggressive environments
EV Battery Explosion-Proof Vent Valve	High-energy battery modules needing controlled pressure release to prevent rupture
General Plastic Vent Valve	Lightweight, cost-effective solution for consumer-grade battery devices

How Vent Valves Work in EV and Battery Pack Systems

Breathable Membrane Venting

Most plastic vent valves rely on a microporous breathable membrane that:

・ Permits air exchange

・ Repels water (hydrophobic property)

・ Filters out dust and particulate matter

Pressure Relief Mechanism

When internal pressure exceeds safe thresholds:

・ The membrane expands to open a vent pathway

・ Excess gas escapes safely to the outside

・ The enclosure returns to normal pressure levels

Explosion-Proof Function

Explosion-proof models are equipped with:

・ A rupture disk for emergency pressure release

・ Directional venting pathways to control gas flow

・ Reinforced housing to withstand pressure impacts

These features ensure gas is discharged safely and predictably during emergencies.

Key Applications in New Energy Mobility

Vent valves are essential components in:

・ EV & PHEV Battery Packs: Protect battery modules, BMS units, and high-voltage junction boxes

・ E-Bike & E-Scooter Battery Packs: Prevent internal condensation and extend service life

・ Energy Storage Boxes & Power Batteries: Ensure safe, long-term cycling in outdoor installations

・ Smart Mobility Devices: E-motorcycles, mopeds, and delivery vehicles operating in variable conditions

Core Benefits of High-Quality Vent Valves

・ Boosted safety performance and reduced thermal runaway risk

・ Reliable protection against water and dust intrusion

・ Extended lifespan of battery systems

・ Lower long-term maintenance costs

・ Enhanced operational reliability in harsh environments

A vent valve may be a compact component, but it exerts a profound impact on the safety, durability, and performance of battery-powered systems. Whether deployed as an IP67 Plastic Vent Valve, Waterproof Plastic Vent Valve, Corrosion-Resistant Vent Valve, or advanced EV Battery Explosion-Proof Vent Valve, proper venting is the cornerstone of stable operation for electric vehicles and new energy mobility products.

As demand for safer, more reliable lithium battery systems continues to rise, vent valves will remain a pivotal technology driving the evolution of the EV and e-mobility industries.