MissionH24, a collaborative project between Le Mans organiser the ACO and H24Project (previously Green GT) have announced the development of a third generation hydrogen fuel cell powered Le Mans Prototype. Following on from the LMPH2G the H24, this is due to start track testing in 2025 and is aimed at attaining LM GT3 lap times.

The new Prototype will use a Symbio hydrogen cell system exploiting what is described by the ACO as “next-gen multi-stack technology. The maximum net power output will be 300 kW. By way of comparison, we estimate that the power density will be 50% greater than the system used on the H24. This latest generation offers high efficiency which has a significant impact on the volume and weight of the onboard storage system.”

Symbio adds: “300 kW net power output for this car equates to what we develop for our heavy mobility customers. The multi-stack system will meet the compactness requirements and the weight, efficiency and heat dissipation demands of competition.”

The fuel cell will feed its electrical output into a bespoke lithium battery, which will also recover most of the kinetic energy available under braking. The target maximum battery power is 400 kW while the target weight is 80 kg compared to the 92 kg of H24 battery.

There will be a single electric motor driving the rear wheels. This will provide maximum power of 650 kW (872 hp) and is targeted to weigh 30 kg compared to the 48 kg for the H24’s twin motor provision. The motor’s power density is targeted as 20 kW/kg compared to approximately 16 kW/kg for a current Formula One MGU-K. The power will be delivered through a single ratio transmission.

Hydrogen will be stored on board in two composite material tanks produced by Plastic Omnium. Each tank will store 3.9 kg of hydrogen at 700 bar for a total weight of around 100 kg. The ACO reports that optimisation of the composite material has lightened tank weight relative to the H24’s tank provision. The target is to run “25 to 30 minutes” between pitstops.