Published on January 16, Stellantis filed a patent application for an electric vehicle exhaust system, but not the kind you might be thinking of. Yes, the Dodge Charger Daytona EV already features a “Fratzonic Chambered Exhaust,” a noise pipe of sorts that mimics the mechanical rumble produced by a powerful internal combustion engine. What engineers have been working on here, however, is an exhaust system for electric vehicle battery packs… wait, what? Yes, you read that correctly.
A Potentially Clever Solution To A Major Issue
Electric vehicle battery fires are a major concern. If one of these things kicks off, it takes a staggering amount of water to extinguish, plus the mélange of materials contained in modern lithium-ion cells releases vast amounts of toxic – and often flammable – fumes when heated. Depending on the chemistry, those vapors can allow a battery fire to become self-sustaining. The hotter the pack gets, the more fumes are released and burned, making the fire even hotter. The technical term for this is thermal runaway.
Potentially heading this problem off, Stellantis engineers have come up with a way of venting and treating noxious battery fumes. “Accordingly, in the event of a thermal runaway, it is desirable that the vehicle include features that assist in preventing, or at least substantially minimizing, the ignition of various gases that are generated during the thermal runaway.”
Aside from providing a channeled outlet for gases, to get fumes out of the battery so they don’t combust, the patent application also covers something else, “the vehicle further includes a tank configured to store a battery gas treatment fluid and a dosing device in communication with each of the tank and the pipe, wherein the dosing device is configured to inject the battery gas treatment fluid into the flow of gases within the pipe.” Chemically treating those fumes is a clever idea that can “eliminate or at least reduce the number of various chemical species from the flow of gases.”
A Mixing Device In The Exhaust System
Helping ensure the exiting fumes are thoroughly treated by the fluid, this patent also includes a mixing device in the exhaust system. This swirls the gases and treatment liquid for optimal effectiveness. Additionally, “As the battery exhaust gas treatment fluid intermixes with the battery gases within [the] pipe, the battery exhaust gases may be cooled … the liquid may undergo phase change to gas,” something that should absorb heat, further reducing the likelihood of a fire.
The patent application continues, “In addition, battery exhaust gas treatment fluid may also react with various chemical species of the battery gases and cause the chemical species to either [become] non-hazardous or less hazardous chemical species.” Basically, it sounds like chemical reactions with the treatment fluid could make the byproducts of a battery thermal event less toxic.
Of course, before an electric vehicle can start venting and treating battery gases, it has to identify if a thermal event is underway. Accordingly, this patent application also includes a range of temperature sensors and controllers to do just this.
This Technology Could Make EVs Safer
Anything that can reduce the possibility of an electric vehicle battery fire is a good thing. While not necessarily common, thermal runaway events are enormously difficult to address.
Right now, it’s unclear when – or even if – this technology will ever find its way into future electric vehicles, but battery venting technology could give future Stellantis EVs a leg up over the competition.
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