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Freudenberg Sealing Technologies has introduced DIAvent® maxFlow, a reversible battery degassing valve designed for controlled venting during thermal runaway events.
Freudenberg Sealing Technologies has developed DIAvent® maxFlow, a new emergency degassing valve for electric vehicle battery housings. The component is designed for battery systems where higher energy densities can generate larger gas volumes during thermal runaway events in individual cells.
Conventional burst disks open under overpressure but cannot close again after activation. They also offer limited flexibility for adjusting the opening pressure and cannot be tested non destructively after installation.
DIAvent® maxFlow uses a profiled metal spring instead of a rubber umbrella. When the defined trigger pressure is reached, the valve opens fully and quickly, allowing hot gases to vent from the battery housing. After pressure is released, the spring closes the opening again automatically.
This reversible function helps prevent oxygen from entering the battery housing after degassing, reducing the risk of further escalation inside the battery system.
According to Freudenberg, the valve reaches an emergency degassing rate of more than 190 liters per second at a differential pressure of 300 mbar. The company states that this is 2.5 times higher than its DIAvent® HighFlow valve.
The activation pressure can be adjusted between 50 and 200 mbar. The component has an installation height of 12.1 mm and overall dimensions of 86 × 86 × 12 mm. It is designed to meet protection classes up to IPX9K and IP6KX and is certified according to UL94 V0.
The valve can be mounted using a universal M6 bolt, with clip and bayonet fastening options also available. An integrated PIP seal compensates for housing unevenness of up to 0.2 mm.
Because the valve is reversible, manufacturers can inspect the fully installed battery pack non destructively during end of line testing. This gives battery and vehicle manufacturers an additional quality control option compared with burst disk based venting systems.
For electric bus and commercial vehicle applications, controlled battery degassing is an important safety function. Components such as DIAvent® maxFlow support thermal runaway management by enabling fast venting, defined activation pressure and post event resealing within the battery housing.
