Introduction

This is a pressure relief valve, used in an EV lithium-ion battery pack for emergency venting. During normal operation, it prevents water and foreign material from entering the battery, protecting the battery modules from short-circuit. In a thermal runaway emergency, it opens reliably to vent gas, release pressure, and prevent damage to the battery while keeping passengers safe.

Features

• Prevents the spread of fire in the battery pack by releasing internal pressure, then re-sealing immediately.
• Valve opening pressure can be set to customer requirements.
• Waterproof breathable membrane (breather filter) can be added.
• Various assembly methods available based on requirements.

When an EV cell ruptures, gas and heat are released and pressure quickly builds in the battery pack. This valve is opened to release that pressure. Immediately after pressure is released, the valve is closed to prevent oxygen and foreign objects from entering, which limits the spread of fire. The opening pressure can be finely tuned by adjusting the internal spring. Nifco also offers non-resealable valves that open quickly to maximize flow.

• Waterproof breathable membranes can be added for pressure equalization during normal conditions.
• Boltless attachment, like a bayonet or plastic thread, can also be selected.​
• Super-high temperature / flame-barrier materials can also be selected.

Nifco is able to replicate valve behavior during thermal runaway using our one-of-a-kind cell explosion tester. Using actual cells in a small module, it is possible to confirm real-world valve performance and see the benefit Nifco’s valves have on actual battery packs. ​

Our customers go beyond automotive. Our valves are used in batteries for both industrial and residential energy storage, as well as construction equipment using Lithium-ion batteries. We have off-the-shelf parts available for purchase, and can support orders of any quantity.