Fast and controlled venting enables effective protection of the housing, the battery, and the vehicle in case of a thermal event
Fast and controlled venting enables effective protection of the housing, the battery, and the vehicle in case of a thermal event.
A ‘thermal event’ or ‘thermal runaway’ are interchangeable terms commonly used to describe the sudden and rapid heating of battery cells due to a defect such as mechanical damage, an electrical short circuit, or overload. This can occur especially in the powerful batteries that supply the propulsion energy in electric vehicles (EVs).
Thermal runaway causes large amounts of gas to form inside the battery housing which leads to an uncontrolled and rapid rise in pressure with serious consequences, such as the complete destruction of the traction battery and even the entire vehicle. Minor pressure differences between the interior of the housing and the environment can also pose a threat to the battery’s integrity and performance.
As a result, adequate venting is crucial to ensuring the protection of EVs, their components, and their passengers.
NEW VENTING SOLUTION
To help avoid instances of thermal runaway, the Prädifa Technology Division of motion and control technology developer Parker Hannifin has introduced CliPHvent, a new generation of vent valves for EV battery housings. In the event of pressure differences between the interior of a housing and its environment, as well as when sudden overpressure occurs inside the housing, CliPHvent ensures controlled pressure compensation, or fast venting. This is particularly important in case of a thermal event in the traction batteries of EVs.
CliPHvent vent valves enable fast venting via an integrated seal in order to protect the battery housing and increase the safety of the traction battery. In the case of thermal runaway in a single battery cell, the valves can prevent the dreaded ‘domino effect’ of the event spreading to adjacent cells followed by rapid propagation across the entire traction battery, leading to its complete destruction.
COMPENSATING FOR MINOR PRESSURE DIFFERENCES
Minor pressure differences between the interior of the battery housing and the environment due to air pressure or temperature changes can be compensated for via a specially-designed membrane. Parker’s Aspire membranes are water and oil-repellent – meeting IP6XK, IPX6K, IPX9K, IPX7 and IPXXB requirements – in order to provide reliable protection against the ingress of external liquids and dirt.
Meanwhile, the compact design of the vent valves enables easy snap installation without the use of tools on the battery housing or inside a bore.
