The Formula E Battery

Motorsport Developments and Formula E

The introduction of Formula E in Beijing in 2014 represented a historical first and a significant advance in motorsport developments because it was the world’s first racing series powered entirely by electricity. The development of cars for the Formula E series has been no mean feat in organisation, engineering and electricity storage with Williams Advanced Engineering supplying and developing the official Formula E battery used by all teams.

Williams Advanced Engineering

Williams are no stranger to motorsport developments in the field of energy storage. Since the 2009 introduction of the Kinetic Energy Recovery System (KERS) they have taken part in the race towards proficient battery design. The development and design of the KERS system that their own team used for a total of three Formula 1 seasons was their own. Their energy storage technology has since proved popular with other teams, at Le Mans, with Jaguar and for public transport.
formula e battery

The Formula E Battery

The Formula E Battery has built on lessons learnt from Williams’ previous energy storage projects and is already a high-tech and refined piece of engineering. In the first season each car drove the equivalent of 1.5 times round the world (60,000 kilometres) and the batteries, which hold as much energy as 10,000 domestic AA batteries and could each charge an iPhone for 13 years, represent an impressive feat of engineering and must be one of the most significant motorsport developments in recent years.

Formula E Battery Requirements

Not only do the Formula E batteries need to meet the FIA’s requirements for consistency and longevity (each battery needs to last for a whole season) they also have to meet an exacting technical specification. Requirements include a 1000V maximum bus voltage (to supply all circuits within the system), a 200kW peak power limit (the maximum flow through the system), maximum usable energy of 28-kilowatt hours (the amount of energy required to run 28 1000 watt appliances) and a cell weight limit of 200kg.

Battery and Motorsport Developments

The development of the battery technology for Formula E batteries is fundamental, not only to the success and popularity of the new series but also to the wider automotive industry and road vehicles. The two main requirements have always been increased battery power and longer battery life. In the early days of Formula E, battery capacity was lacking and only allowed for half a race to be completed without a pit stop and car change. This situation is predicted to change as further developments occur.
motorsport developments

Battery Weight, Size and Other Challenges

Two of the current limiting factors for Formula E battery development are battery weight (which should not exceed 200 kg) and battery size (each battery was required to fit into a pre-designed chassis). Another important aspect for such a large battery is its capacity to cool. Limited cooling leads to limited performance but this challenge has been met by Williams Advanced Engineering’s liquid cooling system.


Improvements to the Formula E battery are ongoing. During season 3 (2016) Williams Advanced Engineering introduced an updated battery. Improvements included:

  • A more robust cooling system
  • 50% more energy regeneration (as per amended FIA rules)
  • Vibration resistant bus bars
  • Improved support around the battery cells and bus system


McLaren and the Season 5 Formula E Battery

In September 2016 McLaren Applied Technologies beat an impressive line up, including Porsche and Williams Advanced Engineering to win the contract to supply new batteries for season 5 of the Formula E motorsport series. McLaren claim that their new Formula E battery will double the storage capacity of the existing one (to a tune of 54kWh) and finally do away with the necessity of swapping cars mid-race. The new battery will also deliver 50kW more power than the existing one, thus increasing the capacity for speed (currently only around 150mph).

The Future of the Formula E Battery

Battery advancement is big business both for road car and motorsport development and, as such, is experiencing a period of rapid improvement and evolution. The FIA have recognised this fact in their announcement that the McLaren Formula E battery will only be in use for the next 2 seasons. After that a new contract will be rewarded, this kind of competition is great for motorsport development and it will be interesting to see whether Williams Advanced Engineering step up to the mark and win the contract back in 2020.

For all your motorsport safety requirements, MDD offer the very best in safety cover staff, equipment and motorsport medical services. For experienced and professional help and advice please get in touch with our team today.