As battery manufacturers work toward the development of higher energy density and increasingly smaller battery packs, venting solutions need to keep pace. While dual-stage venting systems have proven to be the key to handling a wide range of battery venting needs, higher density batteries require vents with improved pressurization and degassing capabilities to ensure performance, ease of use and safety. Those advanced venting technologies are available now and set the stage for evolving battery design.
Chemistry and Capacity Determine Gas Production
To specify the appropriate venting solution for EV batteries, it’s critical to calculate the amount of gas that will be produced in the event of a thermal runaway. Whether manufacturing LFP (lithium iron phosphate) or NMC (nickel manganese cobalt) batteries, gas production is dictated by two factors: chemistry and capacity.
Increasing the nickel content of EV batteries increases their energy density, which is desirable, but also increases the amount of gas generated in a thermal runaway event. LFP batteries produce less gas, but also have lower energy density.
Similarly, there is a linear correlation between the capacity of batteries and volume of gas production during a thermal runaway event.
A New Type of Vent for More Rapid Degassing
Regardless of the composition of the battery being manufactured, its venting needs to provide both consistent pressure equalization and rapid degassing in the case of a thermal runaway event. As higher capacity batteries are developed, simply increasing the number or size of vents to accommodate the associated increase in gas production is not practical given the mandate for battery packs with a smaller footprint.
To address the industry’s need for venting solutions that provide faster degassing, Donaldson developed the dual-stage Jet battery vent. Engineered to provide optimal pressure equalization and ingress protection during normal operating conditions, its unique medium-pressure design ejects the poppet and cap to provide a larger opening for gas to escape during an emergency situation, boosting safety and reducing the risk of damage to other battery packs. If the internal pack pressure exceeds the opening pressure of 115 mbar, the cap and poppet jettison, allowing rapid degassing of roughly 100 liters/second @ 100 mbar – the industry’s fastest degassing capability in the industry.
Fewer Vents Needed
Engineers and designers will recognize that the more effective the pressurization and degassing capabilities of a battery vent, the fewer vents needed to provide adequate protection. The dual-stage Jet can reduce the number of battery pack vents required by up to 90%. Fewer vents per battery pack means a smaller footprint, fewer holes per pack and streamlined manufacturing and assembly resulting in effectiveness and cost savings. The Jet also offers easy leak-check capability to ensure the battery pack is appropriately sealed prior to leaving the plant.
Jet It and Forget It
For battery manufacturers looking for small vents with high efficiency, the Jet sets a new standard. It works for all types of vehicles and applications, eliminating the need to re-engineer each battery pack to accommodate different vents. The Jet enables very high degassing for the battery technology of today and the future.
