The battery and energy systems of Formula E cars will change significantly with the introduction of the third generation (Gen3) design in 2022. The Gen3 specifications are scheduled to last three seasons until 2025. In Gen3 cars, the battery will be lighter (so will the entire car), it will be capable of handling fast charging up to 600kW, and the cars will include regenerative braking on both the front and rear axles. The battery will be more costly as well as more complex, with a complete battery system to be cost limited to €250,000 with all parts standardized (including the external charging infrastructure), that is significant in relation to the overall cost of a Gen3 car, which is limited to a maximum of €340,000.

Smaller batteries, faster charging

The battery pack in Gen2 cars weighs 385kg, Gen3 cars will be limited to 284kg for the battery pack, which will have a capacity of 51kWh, down from the 54kWh capacity of Gen2 cars. The lower capacity means that the cars won’t have enough energy storage to complete the race without recharging. And the much smaller weight of the battery packs means that the energy density must be increased.

The Gen3 cars will be able to charge at 600kW, much higher than the best commercial electric vehicle chargers currently available, and up from the 350kW in Gen2 cars. And the cars will absorb energy from regenerative (regen) braking at the same rate, grabbing 250kW from the front axle and 350kW from the rear axle. Only the motor generator on the rear axle will provide propulsion, meaning that the cars will have a maximum power of 350kW (469hp) in qualifying and Attack Mode (for a description of Attack Mode, see the first article in this three-part FAQ series, Formula E Gen2 and Attack Mode). Gen3 cars will be limited to 300kW in race mode. The front motor generator will be for regen only.

More race options

The smaller battery combined with the fast charge capabilities of the Gen3 cars will result in the addition of a required pit stop during the races. The cars will be charged for 30 seconds during the pit stop and will absorb 4kWh of energy, a rate of 600kW. The 4kWh will make up for the smaller capacity of Gen3 batteries (51kWh for Gen3, down from 54kWh for Gen2).

Together with engineers from motorsport governing body the Fédération Internationale de l’Automobile (FIA) and Formula E, ABB’s electrification teams are currently working on the specifications and requirements to develop an innovative and safe solution for charging the Gen3 cars through units that can charge two cars simultaneously.

The ability to charge the cars during the race is expected to bring additional changes to the racing format. For example, races could be longer than the current format of 45 minutes plus one lap. Or, with the possibility of optional pit stops (which would require a change in the rules), teams might be able to drive more aggressively with less focus on maximizing energy efficiency, trading faster lap times for more time spent in the pit recharging the battery.

Formula E steering wheel is a control center

One thing that won’t get any smaller in Gen3 cars is the steering wheel. The wheel may evolve, but it will remain a complex and critical device. The steering wheel is a command center with extensive data displayed on the center screen, including tire pressures, brake temperature, speed and power, the state of the battery, range, and energy consumption. With no telemetry back to the garage, this screen is important throughout the race; drivers regularly report information to their teams so they can consult on strategies and receive crucial feedback and support.

The RAD (radio) button is used extensively during races. Drivers are in constant communication with their race engineers throughout an E-Prix, keeping them updated with all the information presented on the screen or calling out when they need support in the heat of the moment.

The multi-switches offer a range of mappings for the drivers to apply on the fly, giving them immediate access to different settings for the various strategies and managing energy throughout a 45 minute plus one lap E-Prix. The multi-switches are among the most complex components on the wheel – opening access to dozens of variables. The drivers have to juggle all of this in real-time throughout the races.

Other functions on the steering wheel include:

• ATK is for Attack Mode. Used during the race, Attack Mode gives the drivers an extra 35 kW of power. This button needs to be pressed when entering the activation zone. Misjudge it, and the drivers lose not only that additional power boost but also time and even race positions.
• Paddles are used to control regenerative braking and to activate FANBOOST. Before the drivers have even considered braking for turns, they need to lift and coast into a corner. By pulling this paddle, energy can be re-captured and recharge the battery while slowing the car down. The brake pedal can then be used for extra stopping power as required. There’s a set of plus and minus options on the wheel for rapid changes to the strategy, too, and these are connected to the option selected on the switches. Depending on how they’ve been set up, there is also launch mode for race starts and FANBOOST that can be activated through a paddle.
• +/- The plus and minus buttons on the wheel adjust the brake bias, transferring the braking ratio between the front and the rear brakes. This means that the drivers can adapt the brake balance while on the move, ensuring they get the suitable stopping power for each turn on the track. Too much towards the rear, and the car will spin. Too much up-front and the car will be difficult to turn in.
• FCY & PIT – The FCY and PIT buttons are found in all of the cars, and both of these buttons act as speed limiters to ensure that the drivers are at the safe speed when the circuit is under a full course yellow situation or when entering and leaving the pits.

For more insights into current Formula E technology and Gen2 cars, you can read part one of this three-part FAQ series: “Formula E Gen2 and Attack Mode.”

References:

ABB Formula E, ABB FIA Formula E Championship
ABB to supply charging technology to Gen 3 cars racing in ABB FIA Formula E World Championship, ABB
Formula E, Wikipedia