With the growth of electric and hybrid vehicles, lithium-ion batteries are playing an increasingly critical role in the automotive world.
Rechargeable lithium batteries offer high energy-per-unit-volume ratios and can be regrouped in various geometries to fit the vehicle’s space.
Unlike smaller lithium-ion batteries used in home electronics, automotive lithium-ion batteries need robust protection from harsh external conditions, along with adequate venting for temperature and pressure fluctuations.
Dual battery ventilation systems
Dual-stage enclosure protection venting has proven effective in meeting the needs of automotive batteries.
The first stage equalizes pressure (between the enclosure interior and the surrounding atmosphere) while preventing the ingress of water and contaminants. The pressure differential can fluctuate widely during normal vehicle operation due to ambient temperature changes, heat generation in cells, and atmospheric pressure changes. Much like an automobile passenger might experience “ear popping” while traversing mountainous terrain, battery enclosures experience similar pressure fluctuation as elevation changes.
Stage two venting fully opens in the case of rapid pressure and heat buildup to allow expanding gases to escape, preventing further damage to remaining cells. In the rare case when the battery is in the process of burning up, and protection from moisture and debris is less important, the venting system must also be capable of providing immediate pressure relief, avoiding potential explosions and other catastrophic outcomes.
In most instances, a single vent assembly can accomplish both functions. Properly designed venting systems provide protection from contaminants along with pressure equalization during normal operating conditions, leading to longer-lasting enclosures and battery life cycles. Using dual-stage venting systems is the key to handling a wide range of automotive venting needs.
Ilpea supports its automotive customers by producing these venting systems also called degassing lines.
These lines are therefore complex systems with electronic components of high added value that allow to always monitor the pressure and temperature.
Dual (or two-phase) closure ventilation systems are currently the ones that currently allow a higher effectiveness for automotive batteries.
This system is essential for the proper functioning of the vehicle, as well as to ensure a long life for the battery pack.