With total annual viewing figures measured in the billions, motor racing represents one of the world’s most popular televised sports. It gains widespread media attention and generates huge sponsorship revenues. With many of the world’s leading automotive brands participating in some form of motorsport, it provides a valuable platform for these companies to showcase the strength of their engineering credentials.
As well as being of value competitively, car manufacturers appreciate the other plus points that motorsport involvement brings in terms of contributing to their ongoing product development programs. Many of the technological wonders that were first seen on the racetrack have eventually been adopted into passenger cars – resulting in enhancements in performance, improvements in fuel economy and higher degrees of occupant safety. Key innovations that stem from this source relate to hybrid engines, in-vehicle networking, the acquisition of diagnostic data, more effective camshaft arrangements, automatic transmission systems, improvements in aerodynamics, use of advanced chassis materials and regenerative braking.
A New Era of Motorsport Endeavor
With the prevalence of electric vehicles (EVs) now starting to grow significantly, the ABB FIA Formula E World Championship race schedule is now being recognized as vital testbed for automotive ingenuity. With a very engaged and continuously rising global fan base, its E-Prix events are helping to dispel the myth that EVs can’t be exciting. There are an array of high-profile automotive brands taking part in this competition, including MercedesEQ®. There is, once again, huge potential for technology to crossover into mainstream cars – particularly in relation to energy recovery mechanisms or power management systems.
In Formula E, the format is constantly evolving – with teams needing to be able to respond accordingly. For example, the first four Formula E seasons, drivers had to change cars halfway through the race, ditching the one they had originally started with for a second fully charged car. In Formula E’s fifth season (in late 2018), this all changed. From that point onward, the cars of all competing teams needed to have the battery capacity to complete that whole race, without any substitutions. To address this change, the teams’ technical staff have had to make huge steps forward in the operational efficiencies of their vehicles, as well as boosting energy storage densities substantially.
Bringing Formula E Engineering into Real World Scenarios
So let’s now look at the ways in which what is happening on the racetrack will have an effect on the EVs that we will be buying in the years ahead. There are several areas where the technology developed for Formula E Generation 2 race car should have long term benefits to mass market EV designs. Here are some of the most important ones:
1. The battery technology – a key obstacle that needs to be overcome if the commercial uptake of EVs is to be accelerated is allaying consumers’ worries about not being able to travel adequate distances in such vehicles before they run out of charge. Through experimentation with new battery chemistries, combined with improvements to powertrain efficiencies (both of which have been derived from work being done in Formula E race car to some extent), EV models now on the market are capable of covering over 200 miles before needing to be recharged. At the same time, comprehensive roll-out of charging infrastructure and the advent of fast charging technology are each helping to address consumers ‘range anxiety’ issues still further, by ensuring charging can be done in a quick and convenient manner.
2. The powertrain – for the powertrains in both Formula E race cars and mass market EV models the objectives are much the same. These are predominantly to maximize power transfer efficiencies as much as possible (by employing sophisticated motor algorithms, undertaking switching at faster speeds to avoid losses) and supplement battery reserves via use of kinetic energy recovery mechanisms. By successfully achieving these objectives, the rate at which the battery depletes will be slowed and the range that the vehicle can cover before needing a recharge will be expanded.
The main power bus used in the majority of consumer EVs will currently have a 400 V (voltage) rating. Through the impetus provided by Formula E race cars, where higher voltage powertrains are already utilized, 800 V systems are now being developed for mass market deployment. These elevated voltage figures will not be addressable using conventional silicon power discretes. They will instead call for the incorporation of wide bandgap devices, such as those based on silicon carbide (SiC) process technology. SiC already features in the powertrains of Formula E race cars, with its elevated levels of efficiency and resilience to harsh operational conditions proving to be extremely advantageous. ON Semiconductor is playing an integral role in Formula E powertrain development. For example, it has assisted the Mercedes-EQ Formula E Team in developing ultra-efficient powertrain systems through use of superior automotive-grade power devices. The two companies have worked closely together on improving the efficiency levels at the traction inverter power stage. What has been learnt from projects like this is then subsequently being leveraged to improve consumer EV powertrain efficiencies.
3. Fast charging – migration to higher voltages is already underway within the EV mains bus – helping to increase operational efficiencies and combat potential wastage. It will, however, also be of considerable value from a charging perspective, allowing transmission losses to be curbed. Much as prospective EV customers have concerns about vehicle range, they are also keen to ensure that charging doesn’t present unwanted difficulties. The charging technology for the latest generation of Formula E race cars enables 4kWh worth of charge to be supplied in an interval of just 30 seconds. Such speeds won’t be achievable by consumer charging points for a very long time yet (with electrical distribution grids struggling to support this, as well as there being issues in relation to the current carrying capabilities of the charger and cabling). Nevertheless, the period taken to fully charge EVs is constantly being shortened – and this trend will continue, with incorporation of the latest wide bandgap power semiconductor devices being of paramount importance here.
4. Regenerative braking mechanisms – regenerative braking is an important aspect of Formula E race cars, as it means there are greater available energy resources that the race car can access. In a racing scenario, where hard braking is commonplace, there is clearly ample opportunity for regeneration. That said, the time taken to capture this energy during a hard brake is not long enough for it to be transferred back into the battery. Supercapacitors provide a means of temporarily storing the recovered energy, so that it can then be returned to the battery, or applied back to the motor when the race car starts to accelerate again. Inclusion of these supercapacitors is justifiable in Formula E designs, but their high price tag will preclude them from use in consumer EVs, where costs need to be kept in check. Also the brake to run ratio will be far lower in consumer EVs, and so the benefits derived will not be as great. Even so, EV manufacturers are putting a lot of engineering effort into the development of cost-effective energy recovery systems for mass market deployment.
The relationship between innovation in motorsport and the development of better road vehicles is still very much apparent. Formula E race cars like the Mercedes-EQ Silver Arrow 02 are now taking on the mantle as a technology drive Formula E is the global platform for OEMs designing new EV models and specifying the constituent components. The ongoing knowledge transfer that arises from it will be pivotal in enabling society’s vehicle electrification goals to be met.
ON Semiconductor has been heavily involved in this knowledge transfer. The company is able to draw on the experiences it has gained at Formula E racetracks and research centers, plus the expertise it possesses in SiC and gallium nitride (GaN) technology, then apply this to EVs on our roads. In doing so DC/DC conversion can be made more efficient, plus higher voltages and faster switching speeds can be attained. Through such innovations, EVs will become a much more attractive option to the car buying public, and over time this will help to increase the proliferation of these vehicles.