Electric Cars with an Edge: GM’s New Models Get an Exhaust System to Prevent Battery Fires

As revealed in a newly disclosed patent, GM’s system functions as an “emergency exhaust” designed to address “thermal runaway” in electric vehicle batteries.

“Thermal runaway” is a dangerous phenomenon where lithium-ion batteries, when damaged or overloaded, generate heat beyond the cooling system’s capacity. This triggers a chain reaction among the battery cells, producing a significant amount of flammable gas, which can lead to explosions and fires.

In such situations, GM’s emergency exhaust system kicks in. Instead of containing the hot gas within the battery pack (increasing the risk of fire), the system opens valves and covers, venting the gas from the faulty cell. The gas is directed through multiple internal partitions, avoiding contact with functional battery cells, and eventually expelled through a central exhaust chamber.

Despite the name “exhaust,” the structure and function of this system are closer to a pressure relief valve on a water heater than a conventional engine exhaust. Nonetheless, technically, it is an exhaust system as it releases gases generated during the vehicle’s intrinsic operation.

Notably, this system only activates in emergency situations and, ideally, should never need to be used.

General Motors is not the first automaker to explore this solution. Previously, Stellantis, the parent company of Dodge and Jeep, also filed a patent for a similar system, with the difference being the integration of a filter (similar to a catalytic converter) to remove harmful components from the battery exhaust gas.

Nonetheless, both systems aim for the same goal: minimizing the risk of fires and explosions, protecting users, vehicles, and surrounding areas, especially in post-collision scenarios where electric vehicle battery structures may be compromised.

One of the most significant risks associated with electric vehicles today is smoldering battery fires. When the heat generated is not sufficient for an immediate explosion, it can smolder and spread, leading to a massive fire after hours or even days. Such incidents have occurred in parking lots, garages, and even residential homes.

Developing an emergency venting mechanism, as GM is doing, could help steer the automotive industry’s approach to battery safety. Instead of solely focusing on preventing incidents, manufacturers are now also building systems to mitigate damage when incidents occur.

Unlike simulated engine exhaust sounds, which are mostly aesthetic or emotional, GM’s exhaust system is utilitarian and designed never to be needed. But if required, it could be the difference between replacing a battery and losing the entire vehicle, garage, or worse.

With the global number of electric vehicles on the rise, the advent of such technological solutions may play a crucial role in dispelling doubts about the safety of lithium-ion batteries, which currently dominate the market.

TH (Tuoitrethudo)