Caterham has revealed its EV Seven – a concept which will test the feasibility of a lightweight electric Seven and enable Caterham to move a step closer to bringing a battery electric model to market that is as driver focused as its petrol counterpart.
EV Seven is being engineered in collaboration with Swindon Powertrain Ltd and is based on the larger Seven chassis, featuring a bespoke version of Swindon Powertrain’s E Axle, combined with an immersion cooled battery pack.
Immersion battery cooling uses a dielectric fluid, in this case supplied by Motul. The fluid is in direct contact with the cells enabling better thermal management during charge and discharge cycles.
Any electric Seven must be useable on both the road and track. For the latter, this means being capable of a repeatable 20-15-20 drive cycle: the ability to drive on track for 20 minutes and recharge in 15 minutes with enough energy to drive for a further 20 minutes.
Building a Seven that’s capable of a Sunday morning drive is achievable with current battery technology, but the challenge is for track use where the energy consumption is greatly increased. At the moment, immersion battery cooling is one of the best solutions in terms of coping with the rapid charge and discharge cycles that would be experienced on a race track.
The weight increase is less than 70kg compared to the current production Seven (meaning a total mass of just under 700kg). Its 51kWh immersion cooled battery is housed in the engine bay and transmission tunnel and is capable of DC rapid charging speeds of up to 152kW. It has a useable capacity of circa 40kWh, safely allowing the battery pack to withstand demanding track use followed by rapid charging without causing premature degradation.
The EV Seven concept will make its public debut at Goodwood Festival of Speed in the UK this July. Caterham is also developing another fully electric sports car concept that it will reveal this year.
