Formula 1 teams are typically cagey about sharing anything about their respective drivetrains. There's big advantages to be had under the hood after all, but now that powertrain development is frozen until 2026, Mercedes is giving us a very detailed look into how its hybrid system works. And it's extremely interesting.
Like all other teams' systems, Mercedes' drivetrain consists of a combustion engine, two electric motors, a battery, and lots of power electronics. One motor is integrated into the turbocharger and harvests energy from the exhaust. It can also provide instant boost to the engine as long as the battery contains enough energy to do so. This is called the MGU-H, and it's going away for 2026. Apparently, it's very complicated to get right, and F1 thinks developing this part in particular has prevented automakers from joining the grid as engine suppliers.
The other electric motor is integrated with the gearbox. It can provide power directly to the rear wheels and harvest energy under braking. This component is maintained as a part of the new regulations.
These systems work together with the power electronics and battery, which is shown in Mercedes' video in incredible detail. The battery pack itself consists of around 200 individual cells, likely of the 21700 variety (called as such because they are 21mm in diameter and 70mm long). They get packed into the same box as the inverters and power electronics, and everything gets cooled on a common loop.
The video focused on this cooling loop, particularly because Mercedes' title sponsor, Petronas, developed the coolant. It's dielectric, meaning even if it did leak into the power electronics, it wouldn't cause a short. These kinds of insulating coolants are commonly used in hybrid and electric vehicles, but we can assume the sort used in F1 are especially effective.
Overall, this is an unprecedented look into the structure and working nature of an F1 hybrid system. If you've ever been curious about how it all works down to the cooling loops, this is a great resource. Now only if other teams would put so much effort into showing off their tech. It would be fascinating to see how other manufacturers solve the same problems.
