--- title: "Here’s Why GM Designed a Gas Exhaust for EVs" date: "2025-06-06" modified: "2025-06-06" authors: - name: "Byron Hurd" job_title: "Editor" link: "https://www.thedrive.com/authors/byron-hurd" url: "https://www.thedrive.com/news/heres-why-gm-designed-a-gas-exhaust-for-evs" categories: - "Cadillac News" - "Car Tech" - "Electric Vehicles" - "News" - "News by Brand" - "Patents" tags: - "Electric Vehicle" --- # Here’s Why GM Designed a Gas Exhaust for EVs ![2026 Cadillac Lyriq-V]() *\Cadillac\* Every few months, it seems like somebody comes along and tries to put an exhaust system on an electric vehicle. [Dodge's physical sound generator]() is perhaps the most novel attempt at something we'd consider a traditional "exhaust," but GM [just patented something]() that is long on function and short on form. It's an emergency exhaust designed to head off a rare but catastrophic condition known as thermal runaway. Under normal circumstances, an EV only emits heat, rendering a traditional exhaust system pointless. *Too much* heat, however, is a potentially serious problem. Thermal runaway happens when, as a result of defect or damage, the battery begins to generate more heat than its cooling system can disperse, starting a chain-reaction effect that produces flammable gasses. It's the precursor to [everybody]()'s favorite[ electrified euphemism](), the *"[thermal event]()."* You know, fire. > [Salt water warning 😳]() > by[u/Sir-Kyle-Of-Reddit]() in[electricvehicles]() GM's patent describes a system designed to help prevent thermal runaway from instigating a thermal event. To call it an "exhaust" seems a bit generous; it's more like an elaborate wastegate. Essentially, it consists of a series of valves and/or caps that physically release the hot, combustible gases being generated within the malfunctioning battery cells and shunt them through a series of baffles that divert them away from adjacent cells and into a central exhaust chamber, where they're vented to the atmosphere, removing heat from the pack and eliminating potential ignition sources all in one go. ![]() ![]() While the greatest threat of fire would come from within the EV's battery, GM doesn't address the fact that it would expel combustible gases into what could be a chaotic, post-accident environment. Stellantis [applied for a patent on a similar system]() earlier this year that incorporated a scrubber (akin to a catalytic converter) to remove unwanted components of the expelled mixture. Functionally, what GM has designed here has more in common with that emergency relief valve hanging off the side of your water heater than it does with a traditional internal-combustion exhaust system. But, it is *technically* an exhaust system. Ideally, a car equipped with such an "exhaust" would never utilize it. But in the event of an accident or a defective/damaged battery, it could mean the difference between replacing a dead pack and rebuilding a burned-down garage—or home. Sounds like a winner. *Got tips? Send ’em to tips@thedrive.com* ## Author Byron is an editor at The Drive with a keen eye for infrastructure, sales and regulatory stories. He brings a light, punchy style to all of his content, believing that there's plenty out there to be laughed at—himself included. Born and raised in Maryland but now based just a stone's throw from Detroit, Byron is an auto enthusiast and generalist who enjoys building and tinkering with things of all kinds, from cars, computers and digital cityscapes, to the new garage that will soon house his fleet (a CT4-V Blackwing, a JK Wrangler and an NA Miata). Inspired by an early love of rollercoasters, Byron quickly caught the high-performance driving itch. He's been tracking and auto-crossing his cars since 2007. In his downtime, Byron enjoys reading, playing city builders, and studying the history of the Motor City. ### Author social links [Bluesky]() [Instagram]() [LinkedIn]()