There are three structural components in a Formula E car. The monocoque from the front to the bulkhead behind the driver is from Dallara and is mandated - standard on all cars; as is the front suspension, all the bodywork including aerodynamic appendages and rear crash structure, and all four wheels and tyres. Behind the driver is the battery pack and control electronics which is a structural member. The battery pack and control electronics are also mandated and currently come from Williams Advanced Engineering. (Next season batteries with more capacity from McLaren Technologies replace the current pack.) Bolted on to the back of the battery pack is the motor(s), drive train (some cars do not have gearboxes because of the torque from an electric motor), and rear suspension, all of which is non-mandated - i.e. proprietary - and varies from team to team - some use single motors, some dual.
The battery pack is immensely powerful. Peak output is 200 kilo watts, which is a serious amount of power. This necessitates special safety requirements. Lithium batteries not only pack a punch but they also emit flames if pierced. So the inside of the battery pack is made of zylon which is 1.6 times stronger than kevlar. If you look closely at the Dragon car in photo 4 of my article you will see a green light on ahead of the cockpit and an obscured green sign on the roll hoop which says 'Green Light On'. This means the car is safe to touch. If any of the electronics go open circuit as a result of a crash the light turns red and the marshals must not touch the car until the electronics are made safe.
The photo above which was not used in the article highlights the safety concerns graphically. Electrocution causes the hand of the person being shocked to lock - so if a mechanic gets 200kW through their hand they cannot let go of the car. In the photo the battery pack is being worked on. So not only is the mechanic wearing protective gear, but the rules require another mechanic to stand behind him with a yellow plastic hook - seen in my photo - which is used in the event of electrocution to literally drag victim off the car.
They may not sound like racing cars but there is much of interest in a Formula E car, and I don't think the story about them has been told very well.
Next year - season 5 - Formula E has a new 'standard' car from Dallara which is very futuristic.See photo below.
Spark is the French company that actually services the teams - provides the parts to Dallara's specs. At Marrakesh one team shunted their car in qualifying and crushed the nose. The mechanic trotted off to the Spark shipping container/shop with a credit card and bought a new nose. They don't paint the cars, the colour schemes are all vinyl wrap applied with a heat gun to fit it to contours. Note the season 5 car does not use the controversial 'halo' adopted by F1, instead it uses a raised windshield.