Williams already working on Formula E season three battery

The supplier of all the batteries for the current championship, Williams Advanced Engineering is likely to be the only company providing energy next season, despite stated ambitions from other companies such as Rimac and Renovo.

“We have already started working on the battery for season three,” Williams Advanced Engineering operations manager Gary Ekelrod told Motorsport.com. “We have to manage our lead times as best we can, so we have started that development activity.

"The roadmap for season three has changed slightly but we can’t go into the specifics of those as they are still confidential.

"But it has been shared with us and we want to improve our product as well."

Motorsport.com understands that the battery will be upgraded slightly for better cooling for the 2016/17 season, but it remains to be whether a 32 kWh battery in season three can be achieved.

A major priority of the future upgrades and development is weight.

“Weight is a challenge. But a lot of that is dictated by the weight limit which is allowed from the FIA in terms of lithium-cell iron weight, which is 200kg,” continued Ekelrod.

“But a lot of that is generated by the energy requirements. So if we are talking about a single car for season five [as the roadmap stipulates], that is fifty kilowatt hours, almost double what we have now, so without a significant chemistry change or a significant weight change in the cells it is going to be very, very difficult to achieve. But I am sure over a time we will find a way to get there.”

Pre-conditioning key to getting best from the battery

The current battery supplied by Williams Advanced Engineering to all of the teams has shown exceptional reliability during the first year of the championship, especially considering the concertinaed timeframes the manufacturer had to teal with it last year.

Yet still it appears some teams are able to extract the best from the unit over others.

“Thermal management of the battery is one of the biggest challenges,” said Ekelrod. “We use the term thermal management as opposed to heat control because it is not just about hot the batteries get but it is also about pre-conditioning, as opposed to post-conditioning, because these batteries work in a very specific temperature window.

"If they are too cold they are inefficient, if they are too hot that is not good either.

“Our dielectric cooling system is an innovative concept of how we cool this battery. It is quite confidential in terms of exactly how we do it but at the same time we think we have got the balance right. “

The dielectric (non-conducting fluid) cooling system developed by WAE is a closely guarded secret but is believed to be a variation of a simple coolant loop.

This is because of the cell orientation, which is non-conventional within the battery itself as most commercial electric vehicles' battery systems have air-cooled systems.

“It is not just what about the battery is capable of, it is also about the strategies that the teams themselves adopt,” states Ekelrod. “Some teams last year knew exactly how to pre-condition their batteries and how to time it right.

"Those batteries sitting on the starting grid, they don’t even have to be running and at thirty-six degrees ambient [top temperature last year in Buenos Aires], those batteries are climbing in temperature.

"There are some teams that can judge it properly and some that don’t, and those that don’t can start running in to temperature problems in the race, while others time it perfectly, so there is a lot of team strategy involved in both managing the battery from an energy perspective but also from a thermal perspective.”