Three rapidly advancing technologies are driving this collective race towards zero-emission e-mobility: WBG devices, more power-dense batteries, and faster charging capabilities.
Since its inception on a paper napkin more than a decade ago, Formula E has evolved rapidly as a motorsport with a mission. Entertainment aside, this electric streetcar racing’s founding mission is to showcase sustainable mobility to the world, and it has done pretty well. It’s the only motorsport to have ISO 20121 certification for net zero carbon footprint since its first race in Shanghai in 2014.
Getting the Formula E car into pole-position entails a lot of hardware and software technology to extract maximum efficiency from the electric vehicle’s (EV) powertrain and battery. For the key automotive OEMs, it’s not just about getting their car across the checkered flag first.
With billions of R&D dollars poured into developing better EVs, the goal of participating automakers goes beyond the championship trophy. Learnings from these high-intensity races are applied to improve electromobility technologies back in the R&D labs.
Three rapidly advancing technologies are driving this collective race towards zero-emission e-mobility: wide-bandgap (WBG) devices, more power-dense batteries, and faster charging capabilities.
Efficient power conversion with WBG devices
A lot of power conversion takes place in the EV. A DC-DC converter for example, steps down the power from the high-voltage EV battery to 12 V, with further conversions to run onboard systems like lighting, radio, and air-conditioning (see figure 1). WBG devices such as Silicon carbide (SiC) and Gallium nitride (GaN) semiconductors are used in transistors to facilitate this power conversion throughout the vehicle.
GaN applications are an emerging technology area, and developers find it hard to validate their design for these high-performance power converters. Increased frequency and higher power affect the reliability of measurements needed to characterize the device’s performance. It can be hard to distinguish whether the measured signal is the device’s characteristic or caused by the measurement setup.
More engineers are beginning to use a new double-pulse test method to get reliable and repeatable measurements, and also ensure their designs conform to JEDEC standards for WBGs. This in turn translates to more reliable power converters for EVs.
Better (and cheaper) EV batteries
During the first Formula E race at the Beijing Olympic Green Circuit on 13 September 2014, racers had to factor in mid-race car swaps as their 28 kWH batteries ran out of juice. These days, racers no longer need to change cars as battery capacities are almost tripled, while maintaining their size and weight. The same battery technologies that enable such improvements in racing performance are also helping automotive OEMs to assuage consumers’ range anxiety.
Prices of EV batteries have dropped by over 80% in the last decade, but that trend is hard to maintain. According to Argonne National Laboratory, a single EV Lithium-ion NMC532 battery could contain around 8 kg of lithium, 35 kg of nickel, 20 kg of manganese and 14 kg of cobalt. With rising prices of these metal commodities, EV battery manufacturers continue to face the challenge of keeping the cap on battery costs. Better battery life cycle design and test strategies and battery test solutions help play a major role to achieve higher performance specifications while lowering costs.
Most EV manufacturers guarantee their battery lifespan for eight to 10 years. Many consumers may change cars before the end of warranty, so battery developers are fully aware the onus is on them to plan out the entire battery life cycle. This including battery second life where they can be re-purposed for less-demanding grid-connected energy storage applications, and efficient recycling methods to recover the battery materials.
EV charging technology
Next to expecting more powerful and longer-lasting batteries, consumers also rank ease and speed of charging as major considerations as they weigh the pros and cons of making that switch from fossil fuel to renewable energy sources to power their cars. While there are governmental schemes to reward EV ownership, funds are also flowing into various initiatives to develop EV charging infrastructure. The latter is boosting a growing market for EV supply equipment (EVSE) – from wall boxes to fast-charging stations, and wireless charging.
For EV and EVSE manufacturers, ensuring interoperability and conformance to industry standards are critical for the success of their products. Factor in local electrical regulations and the mix of EV models, the permutations of EV and EVSE design and test criteria can get mind-boggling. To help advance their innovations, many EV and EVSE manufacturers are investing in emulation solutions that can help them save time and cost. These design verification set-ups use machines that can emulate both an electric vehicle or a charging station, solving the challenge of testing a single new product against different EV or EVSE models.
Developing EV and EVSE products require high power, and the electronic loads convert energy to heat, which can cause significant temperature rises in the test rack. This can lead to measurement errors, and add to the cost of air-conditioning needed to dissipate the heat. To solve this challenge, engineers are turning to regenerative power supplies, which can safely return energy to the grid, thus eliminating additional costs to remove the excess heat, and adding to the green agenda.
The race ahead
The electromobility race is set to get more exciting, be it in the Formula E circuits, or in the automotive market, as car makers strive to see their marques gain more market share. While the individual goals may differ, the collective goal of striving for a more sustainable future through technology remains to be achieved.
About the Author
Hwee Yng Yeo is the Industry Solutions Manager for Automotive and Energy at Keysight Technologies.