Navigant Research Blog

48V Electrification Adoption Accelerates with 2018 Audi A8

— July 13, 2017

Adoption of 48V light electrification is beginning to accelerate in Europe with the debut this week of the fourth-generation Audi A8 at an event in Barcelona, Spain. After launching a 48V system on the high performance SQ7 SUV in 2016, the A8 becomes the first model from the brand to adopt the technology along with mild hybridization as standard fitment across the lineup. This comes just a week after Volvo announced that it would make 48V mild hybrid powertrains standard on all of its vehicles between 2019 and 2021.

48V Vehicle Sales

Navigant Research’s Low Voltage Vehicle Electrification report projects that more than 9 million vehicles will be sold annually with 48V electrical systems by 2025. Europe and Asia Pacific will be the primary markets.

Annual 48V System Sales by Region, World Markets: 2016-2025

(Source: Navigant Research)

The A8 becomes the first vehicle on the market to utilize the 48V architecture as its primary electrical system. It will still include a 12V subsystem to support the many components such as infotainment and lighting that have yet to be redesigned to support the higher voltage. While last year’s SQ7 used its 48V subsystem primarily to support the addition of an e-turbo to the diesel V8 engine, the A8 harnesses 48V technology much more deeply.

From the production launch in the coming months, all gasoline and diesel A8s will have a belted starter-generator mild hybrid system. In addition to providing some electric propulsion assist, the system provides enhanced auto stop-start at speeds up to 13.7 mph; it can recover up to 12 kW of power through regenerative braking. The system will enable sailing with the engine off at speeds between 34 mph and 99 mph. This technology will be applied through all five engines that are planned for the A8. Audi also plans to offer a high voltage plug-in hybrid variant with more than 30 miles of electric range and wireless charging capability, but no on sale date has been announced yet.

Fuel Efficiency and More

While mild hybridization will enhance the A8’s fuel efficiency, the increased electrical power of the 48V system will also enable several new features on Audi’s flagship sedan. Among those is a fully active suspension system that can move the wheels and dynamically change the ride and handling characteristics of the vehicle. Many OEMs offer variations of adaptive and semi-active suspension, but Audi has added a unique element to its system. When an impending side impact is detected by the sensors, the suspension automatically lifts that side of the vehicle, bringing the side rail up closer to bumper height and providing additional protection to vehicle occupants.

In addition to adopting 48V electrification, Audi is pushing automation in its latest vehicle launch. The A8 features what is claimed to be the first Level 3 automated system. The Traffic Jam Pilot can provide fully automated driving at speeds up to 37 mph in heavy traffic on divided highways. It utilizes radar, camera, ultrasonic sensors, and the first production lidar scanner in an automotive application. Like Cadillac’s upcoming SuperCruise system, the Traffic Jam Pilot is designed as a hands-off system and features a driver monitoring system to ensure the driver is ready to take over if needed. If the driver falls asleep or appears tired, the system will provide alerts. If the driver doesn’t respond, the car will automatically pull over and stop. The system only works in traffic; as soon as things clear up or speed rises, it returns control to the driver.

Increasing levels of driving automation and electrification are coming to market quickly, and the new Audi A8 is another step in that direction.


The Unsettled Future of the Electric Powertrain

— March 13, 2017

I recently attended the conference on automotive 48V systems in Berlin organized by BIS Group. My key conclusion is that the electric powertrain is far from a settled science. Many that presented are enthusiastic about 48V technology and its potential for the future. German startup company Volabo even presented the case for a 48V all-electric vehicle. Others see 48V as an interim measure primarily to help OEMs pass the 2020 European Union emissions targets in the short term, with a future going more toward all-electric and full hybrid. Even though production plans have only been made in the last couple of years, powertrain development company AVL told me that testing of 48V systems has been going on for at least 10 years.

Unsurprisingly, Denso has a less enthusiastic opinion of 48V technology than some of the other delegates. The Japanese market has firmly embraced full hybrid drive thanks to Toyota and Honda; the majority of the vehicles on Japanese roads are small cars and trucks with efficient gasoline engines.

A good portion of the engineer audience thinks that an all-electric vehicle future is coming sooner rather than later. However, others are more in line with Navigant Research’s global vehicle forecast that the internal combustion engine still has a long future.

Low Voltage EVs

Volabo is a startup company spun out of a Munich university. Its proposal is a new type of electric motor that uses no copper winding and uses power electronics to control the magnetic fields. High power is made possible by locating the battery close to the motor, connected by thick bars rather than wires to handle the high currents of up to 5,000 amps. Prototype manufacturing for this motor is at the early stage, and there is a lot of interest from other delegates.

Indian OEM Tata’s European Tech Center has examined the market for 48V systems in India and concludes that the market will only be in the C-segment and luxury due to the cost increment. The bulk of the Indian market is very low cost small cars. Typical Indian drivers do not like stop-start systems (and deactivate them if fitted) because fractions of a second delays matter in navigating typical traffic jams. Plug-in EVs are also not likely to be popular in India in the short term because of the unreliability of the local electric grid.

Higher Power Demand

Magna International agrees with one of the key conclusions from my presentation: automated driving systems will support the move toward 48V systems, with demand of up to an additional 10 kW for computing and electric controls that is simply impractical from 12V networks. McLaren Applied Technologies presented some of its development work for racing that is finding its way into volume production. Silicon carbide semiconductors, for example, are prompting performance improvements, and now development work is moving into gallium nitride.

48V Projections

48V automotive systems appear to be an immediate solution to meet upcoming stricter emissions legislation and to provide additional power for automated driving systems. In the short term, these systems will be important in large markets such as Europe, North America, and China, and less so in Japan and India. The longer-term future is somewhat dependent on the growth of high voltage hybrid and all-electric drive, which in turn rely on continued reduction in battery cost. More analysis of the market for 48V systems is available in the Navigant Research report, Low Voltage Vehicle Electrification.


Low Voltage Is the Entry Point to the Full Vehicle Electrification Spectrum

— May 11, 2016

Electric Vehicle 2There is little disagreement in the auto industry that the future of propulsion systems includes increasing levels of electrification. At some point in the future, the internal combustion engine will almost certainly fade into history. However, between now and that indeterminate future time, the comparatively low cost and incredible convenience of using liquid fuel-burning vehicles will ensure that they remain the most common form of transportation. Despite that, a full spectrum of electrification solutions will make these engines more efficient until we reach that future convergence point.

Recently, stakeholders from both the OEM and supplier sides of the automotive industry came together in a suburban Detroit hotel for the 3-day Low Voltage Vehicle Electrification Summit, which raised just as many (if not more) questions than answers about the potential for intermediate electrification. The statement that can be made with any degree of certainty is that there is no silver bullet on the horizon that will suit every application.

Stop-Start and 48V

Navigant Research’s Stop-Start Vehicles report projects that nearly 60 million vehicles annually will include at least basic automatic engine stop-start functionality by 2024, while the 48-Volt Systems for Automotive Applications report projects that more than 7 million vehicles will have 48V electrical systems over the same timeframe.

Stop-start capability with 12V electrical systems has already become relatively ubiquitous in Western Europe, and deployment is expected to expand rapidly in North America in the next several years. However, 12V systems are already being stretched to their limits with all of the power-drawing features and amenities included in today’s cars and trucks. With a practical power limit of 3 kW from a 12V system, the actual use of stop-start is often limited by the need to maintain power levels for essential systems such as the vehicle electronics.

With up to 10 kW available, the additional power capacity provided by a 48V system will enable engineers to deploy more capable semi and fully autonomous systems, which can draw up to 4 kW for the actuators under peak load transient conditions. More importantly, from an efficiency standpoint, 48V systems can enable energy recuperation, sailing at highway speeds, and engine shut-off at higher speeds before the vehicle comes to a complete stop. These enhanced systems can also provide sufficient power for electric superchargers and the electrification of ancillary systems such as oil and water pumps.

Not an Easy Transition

However, the transition is not as simple as installing a bigger battery and generator. Many existing vehicle systems will stay at 12V in order to take advantage of economies of scale, so there must be mechanisms to handle dual voltage. There is also the question of the best type of energy storage to use. Lithium ion batteries are lighter but more expensive and have poor cold engine start characteristics. Various types of advanced lead batteries such absorbed glass matt and lead carbon are already in use or in development, but they each have their own issues.

There is also the overall cost-benefit analysis as high-voltage electrification becomes more affordable. At what point does it make more sense to skip 48V, which can add $800 to $1,000 or more to the cost of a vehicle, and just go high-voltage?

These questions and many more will be discussed at the PlugVolt Battery Seminar taking place at the Sheraton Detroit Metro Airport Hotel from July 26 to 28. More than two dozen speakers will be on hand to discuss battery chemistry, automotive applications, and grid storage.


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