By Manish Mahesh Menon
With each passing year, vehicles manufacturers are adding more creature comforts to attract customers, thereby making vehicles more complicated because of the numerous systems that have to run in tandem to support the different features. For example, a luxury vehicle is estimated to run roughly 100 million lines of software codes on 70-100 networked electronic control units (ECUs). The impending launch of Level 3 and 4 autonomous vehicles will make vehicles even more power hungry due to the massive surge in computing power these new vehicles will require. This, along with the need to adhere to stricter emission norms anticipated in 2020 and 2025 has created the need to upgrade the onboard power-net.
Since the last decade or so, auto manufacturers have been actively seeking to replace mechanically driven components with more efficient electric counterparts such as electric power steering, electric pumps, and electromechanical dampers. In the quest to have zero fatality on the roads, automakers are also offering advanced driver assistance systems (ADAS) such as lane keep assist, adaptive cruise control, and automatic emergency braking. This, along with the addition of comfort and convenience features such as infotainment devices, heated seats, heated steering wheels, and heated windshields, has pushed the age-old 12v electrical power-net to the maximum. To accommodate the need to for more power, better management of power, and to offer safer vehicles, automakers have proposed to use a dual voltage architecture consisting of the traditionally used 12v power-net and the 48v power-net to create a new voltage architecture that will be the stepping stone of future vehicle E/E architecture development.
The use of higher voltage enables a cross section and weight reduction of the wiring harness, thereby contributing towards lighter vehicle architectures and emission reduction.
Secondly, electrifying certain components means better performance in terms of instantaneous response, better power management, and the chance to recuperate energy while braking.
While the above-mentioned benefits can be achieved by full hybrids along with other added benefits, the key differentiator is cost. Real world tests have confirmed that vehicles equipped with 48v are able to reduce CO2 emission by 12-15% which amounts roughly to 70% the benefit at roughly 30% the cost associated with full hybrids. 48v mild hybrids can therefore act as the ideal stepping stone for the automotive industry to drive sales of full and plug-in hybrids.
Among the supplier base, Continental, Bosch, Schaeffler, NXP, Infineon, among many others, are actively working in close coordination with OEMs to develop 48v-specific solutions.
First generation applications of 48v are intended to be introduced for power hungry equipment such as start-stop, climate control, and electrically powered interior systems such as power windows and automatic door closures, and inefficient mechanical systems such as such as compressors, roll stabilizers, and suspension dampers.
A secondary subsidiary board-net at 48v complements the traditional 12v board-net by offering the advantages of hybridization without the complexity associated with electric and hybrid vehicles. Migrating part of the vehicle components to 48v and using dual voltage architecture (12v-48v) positions 48v as a technology that can reduce CO2 emissions, yet improve vehicle drivability.
In addition to a long list of technical challenges such as electric arcs, safe operating voltage, and 48v power distribution, migration towards 48v on-board power systems has to be economically and commercially viable. For now, it seems the need to migrate to 48v is accepted as a given to meet the high electric power consumption needs and the imminent 2020 and 2025 emission norms.
However, not all components and systems designed for the present 12v board-net can be migrated to a 48v board-net and such a migration incurs massive investments across the entire ecosystem. Today, there are many more systems that make up the vehicle, thereby exponentially increasing the potential investment needed for the next step-up to 48v power net. As believed earlier, the challenge for 48v system no longer lies in achieving higher voltage levels. Recent developments in the automotive industry indicate that the single major obstacle to the widespread deployment of 48v remains costly. With a whole new additional 48v power-source and a slew of tests that need to be carried out for internal type approval, the engineering overheads are rather overwhelming for OEMs to absorb. However, according to Frost & Sullivan analysis, this cost may be partially offset as consumers indicate a willingness to pay up to an additional €1000 to avail performance boost across driving dynamics, comfort, and convenience in their next vehicle purchase. As the 48v powered motors and actuators will be downsized, the impact on packaging and tailpipe emissions shall complement the expected performance boost. Yet, the acceptance level of a business case for 48v is still a much-debated topic at the product planning divisions of various automakers, making mass roll-out a challenge.
Another challenge that needs to be addressed before 48v is considered to be a success is the power source. The automotive industry is inclined towards using Lithium-ion (Li-ion) battery as a power source amongst already well-established options such as Nickel metal hydride and Lead acid. A major challenge across the automotive industry with a Li-ion power source is its acquisition cost. A 48v system that uses a Li-ion battery is expected to add several thousands of dollars to the price of the vehicle. Adding further to the cost will be the cost of a DC-DC converter which can cost over a hundred dollars. One major concern that surrounds the use of a Li-ion battery pack is recycling or reuse capability. As things stand, neither the OEMs nor the suppliers are able to answer ‘What happens to the Li-ion battery pack once it exhausts its charge cycle?’ There seems to be no solution to this question so far. Yet, the industry-wide consensus is that the current 12v electrical system has reached its limit as the battery is no longer capable of meeting the rigors of present-day dynamic functions such as blended braking and on-demand boost.
Additionally, voltages beyond 60v require extensive measures to ensure the safety of the occupants of the vehicle. Even ranges the 52v to 54v is considered to be an upper operating range with certain limitations. With functional safety standards expecting some excruciating efforts from the E/E teams in the development of various electronic systems today, OEMs and suppliers are not expected to experiment in the overvoltage range of higher than 54v. Additionally, even for the 48v applications, the entire ecosystem needs to ramp up efforts in development and production in accordance with the ISO 26262 standard, which came into effect a few years ago.
On the face of it, 48v technology seems to be a stop-gap technology before the automotive industry completely migrates to electric mobility eventually. However, based on Frost & Sullivan’s analysis, the future of automotive E/E architecture is based on multi-voltage architecture rather than the single voltage architecture used today in a majority of the vehicles or the proposed dual voltage architecture.
Multi-voltage on-board systems might seem economically impracticable, yet, it could still prove to be the best alternative, precisely for economic reasons. A business case hence arises to source 48v components to be used in electric vehicles, thereby operating at multi-voltages and consequently reducing the sticker shock associated with electric vehicles. Such a development will not only catapult the 48v market but will also give the necessary impetus for a wide adoption of electric vehicles. However, fundamental questions pertaining to future vehicle E/E architecture remains, which will eventually be developed and evolve over the coming years as the industry migrates from manually driven conventional vehicles to fully autonomous electric vehicles. The 48v system, however, will enjoy sustainable success only if key components can be standardized and economies of scale achieved to significantly penetrate the automotive industry. Otherwise, else it will end up being an expensive option which will eventually fade out, much like the 42v technology.
Frost & Sullivan recently conducted a market analysis of the 48v market and found out that by 2025, ~7% of the vehicles produced in Europe, North America, China, and South Korea are going to be 48v based vehicles. However, regionally, the adoption of 48v depends on the interest levels of OEMs. Without a doubt, Europe leads the push for 48v with 12% of the vehicles produced by 2025 to be based on 48v, predominantly because of the German automakers such as Daimler Group and Volkswagen Group and the French-Japanese alliance of Renault-Nissan pushing for a quick roll-out. On the other side of the Atlantic though, due to a lack of interest in 48v among the North American OEMs, 48v is expected to be a niche technology initially, which is evident from the sluggish penetration of ~6% by 2025. Tightening fuel consumption norms for 2020 from 34 miles per gallon (mpg) to 47 mpg will force Chinese OEMs to partially or completely skip 48v mild hybrids to offer PHEVs and BEVs. Unlike other regions, where there is a push from European OEMs or an internal push to reduce CO2 emissions, South Korea lacks push to bring 48v into the market, with only the Hyundai Group being interested.
On a segment level, of the 5.69 million vehicles forecasted to offer 48v dual architecture in 2025, more than 90% of the vehicles are accounted for by the C-segment, E-segment, F-segment, and SUV segment. This is predominantly due to the fact that the E and the F-segment vehicles are more often than not are showcased by OEMs as their most technologically advanced vehicle, hence justifying a launch of 48v technologies in these vehicle segments. On the other hand, the C-segment and the SUV segment bring in the volumes to justify the investment on 48v technology.
Different manufacturers plan to use 48v to their advantage. For example, Audi plans to migrate all of its vehicle models to dual voltage architecture in the coming few years depending on model lifecycle changes in order to improve performance by offering chassis and powertrain applications. Other prominent OEMs in this space, such as Daimler, BMW, and Renault-Nissan plan to use 48v predominantly as an emission reduction tool. In the medium term, however, auto manufacturers plan to convert ancillary equipment like pumps and compressors to 48v, allowing for precision control, lighter weight, and compact design, along with large static convenience equipment of the likes of window heating or HVAC.
As things stand, Audi will clearly gain the frontrunner advantage because of its strategy to offer the 48v system as standard in the recently launched A8 with applications such as electric compressors, electromechanical roll stabilizers, and electromechanical dampers offered as standard features. However, it was the Audi Q7 which first brought a 48v application into the market. Mercedes Benz with its S-Class and the Renault with its Scenic are the other vehicles that offer 48v application. Audi’s first mover advantage is highlighted by the fact that by 2025, ~35% vehicles from the Ingolstadt manufacturer is expected to be 48v hybrids in Europe, North America, South Korea, and China. Similarly, Mercedes Benz is expected to have ~40% of its vehicles based on 48v dual voltage architecture across these regions, while Renault-Nissan is the only OEM which crosses the 1 million 48v vehicles cumulatively in these regions.
From the research carried out by Frost & Sullivan, Tier I suppliers are expected to be under immense pressure to meet the requirement set out by the OEMs in terms of product development and costing. Therefore, from the supplier’s perspective, executing the migration from 12v on-board network to a dual voltage 12v/48v on-board network is a challenging process. A complete overhaul of the vehicle E/E architecture is required in order to carry out the migration, translating into a major design challenge for suppliers across the value chain. Suppliers of semiconductors and ECUs will be affected particularly, owing to the need to realign and certainly redesign their products to operate at a higher voltage range. Subsequently, DC-DC convertor suppliers will also need to develop and launch specialized ICs to enable high power transfer.
The Last Word
Automotive OEMs have embraced the 48v power subsystem wholeheartedly, which is evident from a slew of launches in the last 2 years by different manufacturers, signaling their intentions towards a multi-voltage E/E architecture for the future. The impetus for adding another power-net to improve fuel efficiency and reduce CO2 emissions through mild hybridization, while at the same time augmenting the drivability of the vehicle at a fraction of the cost in terms of changing vehicle design and/or manufacturing, makes 48v a solid business case for automakers to invest in. Frost & Sullivan believes that the transition from a 12v power-net to a dual voltage 12v-48v power-net architecture allows OEMs to realize greater power, torque, and innovative features to enable far greater fuel savings. The dual voltage architecture achieves all of the automakers’ goals for the short and medium term at a cost point that has more potential to reach wide-scale adoption than that can be attained by full hybridization since inception.