Part of The Mobility (R)Evolution series
By Jim Witham, CEO at 氮化镓系统 (GaN Systems), and Uwe Higgen, Managing Partner at BMW i Ventures
This is the second article within the series. Click here to read part 1, “The Transformative Forces of Electrification and Autonomous Driving”.
In any industry, an open mindset that enables changes in human attitudes has to exist along with the development and maturation of technologies to create the optimal conditions for mass-market adoption. The attitudes that have historically challenged the EV industry have been non-routine in nature – clustered around issues of driving habits, uncertainty around product reliability, the risk aversion reflected in ‘driving range angst,’ and the uncompromising visceral experience demanded in the vehicle cabin space. The good news is that insights from the first decade of EV deployments are guiding the on-board technologies, design, and manufacturing strategies of the next generation of vehicles and the infrastructure and partnerships needed to support them.
Technology continues to own the driver’s seat in the quest for the holy grail of the 500-mile range vehicle that ‘fuels’ in five minutes. New developments are simultaneously decreasing the vehicle bill of materials while creating power efficiencies and design solutions that were previously impossible to imagine. Technology is no longer a cost barrier to EV adoption. It has become the facilitator and fulfiller of the 21st century human mobility desires of sustainability and accessibility, without compromise to long-held cost, performance, and experience expectations.
Technologies Driving the Near Future Evolution of Electric Vehicles
There are four important areas in which technology developments can address energy efficiencies are:
- Vehicle battery
- Drivetrain’s inverter and electric motor
- Onboard charger
- DC-DC power conversion required for accessory systems
Lithium-based batteries are one of the heaviest and most expensive items in an EV, accounting for as much as one-third of total vehicle weight. Their size needs to be balanced with the on-demand delivery of large amounts of power for the vehicle to perform to consumer expectations. Changes in battery manufacturing capacity, cost, and density, along with efficiency changes in power systems within the EV that use the electricity stored in the battery, are among the most important elements of vehicle change in the EV industry.
The next generation of batteries will be lighter, smaller, and deliver greater vehicle range as a result of new battery chemistries designed to increase power density, married with new power technologies that enable the design of smaller and lighter power systems (and hence lighter vehicles) that more efficiently convert and use the battery’s electric energy. These include the drivetrain inverter, onboard charger (OBC), and DC-DC power conversion.
2. Drivetrain- Electric Motor and Inverter
For electric motors, the economic and technology challenges have been similar to those of batteries – size and cost. While they are five times more energy efficient with lower maintenance costs and a longer lifespan than internal combustion engines, the upfront cost is an average 2.5 times higher. Technology innovation in materials, magnetics, and electronics is leading to the evolution of motors that are more energy efficient (less power loss through heat), compact, and lighter in weight.
Power efficiency, system size, and weight are also the sought-after benefits of technology for the drivetrain’s inverter that converts DC from the vehicle battery into the AC needed by the electric motor. Use of new GaN power semiconductors in inverters is expected to deliver efficiency improvements of more than 70% compared to today’s inverters using traditional IGBT semiconductors. Increased efficiency accompanied by decreased power system size and weight will enable EVs to drive further even with current battery capabilities.
3. Onboard Charger (OBC)
Every EV needs an onboard charger – the physical device that converts AC power from the wall into the DC power that charges the battery. Using GaN power semiconductors results in OBCs that are lighter and approximately one-third current size. This contributes both to a decreased vehicle weight (giving longer driving range) as well as opening up new design flexibility with OBC integration.
4. DC/DC Conversion for Accessory Systems
DC to DC power conversion (400V to 12V or 48V) from the vehicle battery is needed to support accessory systems with low voltage needs such as heating, air conditioning, and power steering. As in the case of the drivetrain inverter, GaN power semiconductors can increase power conversion efficiency (50%) and decrease size and weight (up to 1/3 less) that accrued over the many systems of use in an EV, delivers greater driving range for the same size battery.
Data and Semiconductors Are the New Currency of Autonomous Vehicles
While there are a variety of vehicle types currently being used for ADAS and AV development, inevitably all AVs will also be EVs. It will then be the technologies of sensors, data creation and processing, machine intelligence, and connectivity – all working at real-time speed – that enable the level-by-level evolution from ADAS to full level 5 autonomy.
There is a wide range of estimates about the amount of data a ‘typical’ AV creates in a year. Taking the 4 terabytes of data/day from a 2017 Intel study would yield an annual number of 1,460 terabytes/year or 1.5 petabytes. That is within the order of magnitude range given by other industry estimates at 2 petabytes /year.
The onboard hardware systems core to this data challenge has created overall growth of semiconductor content in AVs. At $695, the average value of semiconductor content in an EV is nearly twice that of an internal combustion (ICE) vehicle, with more than half of that for power semiconductors. An EV with level 2 autonomous driving capabilities adds another 25% in semiconductor value. When full level 5 autonomy is reached, semiconductor content (by value) will be more than double that of a non-autonomous EV and four times that of ICE.
As ADAS evolves to full autonomous driving, there will not only be an increase in semiconductor volume and performance speed requirements but also in needed high levels of reliability. Semiconductors used in AVs must exceed the standards applied against those used in personal computers and mobile devices – which have a first 2 years failure rate of 10%.
Test protocols are being reviewed in collaboration with industry standards organizations to ensure that GaN semiconductor reliability meets auto industry expectations. Given the time-based nature of these kinds of reliability tests, the results are positive with many products approved or in the process of approval. This demonstrates that GaN semiconductors are delivering on energy efficiency expectations while operating appropriately and reliably in actual working environments.
In the near future, ‘zero defect’ programs will need to be established across all automotive semiconductor and ODM suppliers. These programs will have a profound impact on the importance of production process control for automotive semiconductors, and the relationship between OEMs, ODMs, and power semiconductor innovators.
In Part 3 of this series: we discuss the role of charging networks and the need for increased availability of sustainable energy sources.
The next article in this series will be published on Wednesday, August 29th.
In the meantime, check out the three-part Mobility (R)Evolution video series >>