Coil winding breakthroughs will help make electric cars cheaper to build, more efficient to operate and even better for the environment, says Konstantinos Laskaris, Chief Motor Designer, Tesla. As the market for plug-in electric cars expands globally, even as petrol prices remain low, increasing vehicle efficiency continues to be the top priority for manufacturers. Recent developments in regenerative braking, which captures a car’s kinetic energy and converts it back into electricity, have significantly helped to lower consumption.
Further advancements in motor design will boost the engine’s capabilities progressively, said Tesla Motors’ chief motor designer Konstantinos Laskaris in a seminar at the recent CWIEME Chicago exhibition. “The automotive industry is a huge market, maybe the biggest consumer market. Transitioning from Internal Combustion Engines (ICE) to electric systems will gradually increase demand for very high production volume electric motors with the particular characteristics that EVs favour.
“As efficiency is a first-order consideration when powering a device from a battery, more advanced manufacturing technologies will start replacing traditional ones. This definitely involves coil winding technologies that will allow for more efficient and torque-dense motors, as well as steel core technologies that will allow for higher rotating speeds and more power-dense motors.”
For those who still question electric cars’ feasibility or whether they will ever replace conventional cars completely, Laskaris highlighted several advantages of electric motors while acknowledging that there are still a few challenges to overcome.
“The characteristics of electric motors are far superior to those of a combustion engine,” he explained. “An electric motor can deliver twice the power for the same size and provide peak torque from zero speed. Furthermore, it does not require a clutch, does not vibrate during operation, has rapid response, is extremely quiet and is maintenance-free. Its typical efficiency can reach 90%, compared to 25% for an ICE, meaning that the losses of the ICE are seven times higher for the same output power!
“Even given the significant advantages for the electric motor, there are still important design challenges, primarily related to the utilisation of energy stored in the battery. Battery costs can be significantly higher than the cost of motors; when the motor is more efficient, it removes a significant total system cost by requiring a smaller battery for the same range. The challenge here is to maintain the performance while maximising range. ICE engines have the same tradeoff, but maybe 10 miles of range is more noticeable than one mpg.”
Even as electric cars may not be completely environmentally friendly yet, manufacturers are focused on diminishing their impact by designing increasingly efficient engines, as well as comprehensive battery recycling programmes.
“Even when electric energy is produced by coal or other non-renewable sources, the combined efficiency of the power plant and the EV powertrain is higher compared to the efficiency of internal combustion engine cars,” Laskaris said. “Now, when electric energy is produced from renewable sources, the difference is tremendous considering the continuous evolution of electric motor, power electronics, photovoltaics and battery efficiency. Battery recycling is definitely is the solution. Tesla has a complete recycling plan in place, but this a responsibility that every battery manufacturer shares to make sure those batteries are properly recycled for a sustainable future.”
Laskaris noted that these are inherently difficult challenges in the production of all cars and that the real achievement is to find ways to link people’s transportation needs to ever more efficient machines.
“Tesla likes to think we give customers the best balance without sacrifices,” he said. “In the end, it’s how you feel when driving and making sure you get where you want to go. When you put your foot down in a Tesla, you know you’re in something special and you stop caring about all the numbers.”
Laskaris discussed these issues and others in a seminar titled An E-Vision: The new ‘Automotive America’ at CWIEME Chicago 2015. The event, held earlier this month, welcomed a record number of visitors and exhibitors from across the electric motor, generator and transformer manufacturing industries in North America.