Hybrid cars don’t have the same massive battery packs that fill the space under the car like an EV, but they also have to deal with most of the parts of a traditional gas car. That puts the battery back under the trunk or behind the seat, or somewhere else that hurts practicality. Toyota, the king of the hybrids, is working on a way to fix it, and CarBuzz has found the patent that would do it.
But get ready for an exhaust system routing like nothing you’ve ever seen before.
Hybrid Battery Packs Ruin Cargo Space
2007 Toyota Camry Hybrid BatteryToyota
Hybrid cars and SUVs usually have battery packs with between 1-2 kWh of capacity, compared with 60-100 kWh for typical EVs. With the power electronics that go with the packs, they’re about the size of a Chesterfield cushion. It’s not massive, but big enough that it’s tough to find somewhere to put it.
Hybrid car makers put their battery packs where the spare tire well goes on a normal car. Some older models put it upright behind the rear seat. Both places are bad for handling (either high up or behind the axle) and for cargo capacity, but they’re convenient.
Toyota wants to move the battery to under the driver and front passenger. That’s the spot where it would go in an electric car. It’s less convenient, but it’s a much better use of available space. How less convenient is it? Rerouting the car’s exhaust system might be an even bigger change.
An exhaust system normally goes straight back from the engine to the back of the car. It’s the most efficient route, and it uses the center tunnel that most cars already have as part of their design. A battery pack spanning that space complicates things.
Could This New Route Make Hybrids More Fun?
Toyota Patent HybridToyota
Toyota’s engineers are taking a longer route for the exhaust. It would exit and then immediately turn 90 degrees. Then it would bend again, and go rearward along the side sills of the car until it reaches the muffler at the back.
The oddball routing solves a few problems. It leaves room for the battery pack as well as the gas tank. It preserves cargo space in the back of the vehicle. And it lowers the center of gravity, which is good for balance and handling.
It takes advantage of flexible architectures, too. Many modern platforms, like the one used in the company’s own Lexus ES, offer EV and ICE models. Thanks to the EV-forward design, there is room under the car for the battery pack. There is also room for the catalytic converter, which the new invention pushes under the passenger’s feet.
There are some potential problems, though. The car would need a new gas tank design because the exhaust would no longer flow down the middle. It would need extra heat shielding under the floor, and a possible bump-out for the catalytic converter and resonator.
Last but definitely not least, it would be bad for most all-wheel drive systems. Putting the battery in the middle means there is no room for a driveshaft to the rear axle. Fortunately for Toyota, most of its hybrid AWD systems use a motor to drive the rear tires, without a driveshaft or center differential.
CarBuzz Insight – Why This Matters:
2026 Toyota Corolla Sedan Hybrid SE AWD driving front 3/4 angle in redToyota
Repackaging the hybrid power system is a big change. Routing the exhaust under the side of the car instead of the center is another huge variation from the typical car. Toyota says it wants to make fun cars, and this invention could help it make hybrids that are both fun and more practical. That sounds perfectly on brand for the Japanese automaker, or at least for how it wants you to see it.
Patent filings do not guarantee the use of such technology in future vehicles and are often used exclusively as a means of protecting intellectual property. Such a filing cannot be construed as confirmation of production intent.
Source: US Patent & Trademark Office
