Lithium ion batteries have gained popularity thanks to their rechargeability nature, but their advantages don’t stop there. Apart from being rechargeable, these batteries also have a long life span and high energy density, providing them with an edge over other batteries.
These batteries convert chemical energy into electrical energy through electrolysis. During the movement of lithium ions between the positive and negative electrodes, a series of reactions occur that liberate gases such as hydrogen and carbon monoxide and create pressure gradients.
This is where a lithium ion battery vent comes into the picture. This battery safety vent allows for pressure equalisation and the discharge of gases and helps mitigate catastrophic accidents and failures! Even the amendments in AIS-156 guidelines for battery packs mandate the usage of pressure relief vents. Read further to understand the functioning of lithium ion battery vents.
A Battery pack is a sealed enclosure which has to be equipped with a pressure release Lithium ion battery vent. This vent ensures the lithium ion battery safety in harsh internal and external environments.
These safety vents are incorporated into batteries to protect them against temperature and pressure fluctuations that occur due to a myriad of chemical reactions such as redox and decomposition.
These battery vents prevent the buildup of gases, internal pressure, and temperature by allowing them to escape into the external atmosphere, thus ensuring the battery’s safety and longevity.
As previously discussed, a battery safety vent/battery pressure release vent helps liberate gases. So what happens if a battery vent is absent? When internal pressure builds up and exceeds the design pressure of the battery cell, the battery cell can swell up and explode.
Batteries also produce heat during their charging and discharging cycles. Safety vents offer an effective thermal energy dissipation mechanism, and when absent, a thermal runaway event can occur, leading to the hazard of the battery catching fire.
If you consider membrane-based battery venting solutions, these are selectively permeable in nature and thus prevent the ingress of contaminants that can reduce battery functioning and efficiency!
The marketplace offers mechanical and membrane-based vents, which serve their purpose of ensuring a battery’s safety. So, what differentiates a mechanical-based vent from a membrane-based vent?
A mechanical vent is a one-directional pressure relief valve which only opens when the internal pressure increases beyond the design pressure. These vents can have a shorter life than membrane based vents, and one of the major drawbacks in their design is their dependency on pressure buildup.
Since these vents consist of moving parts that are continuously exposed to stress,the chances of them failing and putting the battery at risk are higher.. In addition, a pressure gradient can result in the formation of a vacuum inside the battery.
This vacuum can suck in contaminants such as dust and water vapour, disrupting the lithium ion battery’s performance and efficiency and compromising its safety.
In contrast, a membrane-based battery vent is both porous and bi-directional. This allows a bidirectional flow of gases through the vents continuously.
Membrane-based vents do not allow pressure buildup in the batteries as they equalise pressure constantly, significantly reducing their failure risk. In addition, their selective nature ensures that contaminants are blocked from entering the battery case.
To ensure the maximum safety of batteries, PorVent® conductsa series of in-house tests on its vents, which include a durability test series that consist of Airflow durability test (ADT) and leak durability test.
During these durability tests, these vents were continuously submerged in and out of muddy water and the integrity of the vents and their enclosure were tested. The results declared these vents to be 100% leakproof. The airflow also dropped marginally in these vents, which signified that these vents could function with high efficiency in harsh real world conditions.
In addition, these vents also showed no sign of water ingress, which can be credited to the hydrophobic property of the sPTFE material that PorVent® vents use. sPTFE isa durable material that maintains its airflow even when handled or exposed to harsh environments. The smooth and naturally hydrophobic surface of sPTFE allows water to bead up and roll off very easily without leaving behind residue. It has robust mechanical properties and is an ideal choice for automotive and electronics applications.
A PorVent® battery vent is manufactured from sPTFE, allowing for quick and efficient expulsion of gases into the atmosphere. These vents are capable of pressure equalisation, reducing the stress on the battery seal and preventing premature failure.
Contaminants like water vapour can destroy a battery’s performance and trigger hazardous short circuits. However, these hazards are effectively mitigated with the hydrophobic and oleophobic properties of PorVent® PTFE vents.
These vents prevent the ingress of contaminants and hence ensure the battery’s optimal performance. PorVent® PTFE vents also reduce the condensation rate of moisture and thus help reduce the corrosion risk of sensitive electronic components in batteries.
In stage one venting of PorVent® battery vents, the sub-micron openings in the PTFE membrane allow pressure equalisation and prevent contaminants’ ingress. However, the membrane bursts when the pressure buildup is rapid, allowing the gases and pressure to escape entirely and ensuring no catastrophic event occurs.
With the boom of electric vehicles in the automotive industry, lithium ion batteries are set to leave an indelible mark in the battery industry. From being energy dense to long-lasting, these batteries are power packed with benefits that can drastically improve performance irrespective of where they are being used.
Remember to install a pressure release vent in the battery pack to improve its safety and efficient functionality. If you are looking for the best lithium ion battery vent plug manufacturer for automotive applications, check PorVent®’s vents here!