5 myths shattered about 48-V systems


Technology availability, market and environmental regulations, and infrastructure buildout are aligning to turn a long-forecasted future of full-electric vehicles (EVs) into reality. According to the International Energy Agency’s Global EV Outlook 2020, sales of EVs, including plug-in hybrid electric vehicles (PHEVs), reached a global peak of 2.1 million in 2019, increasing the total number of such vehicles on the road to 7.2 million. 

However, even with 40% year-on-year growth, EVs represent a mere 1% of the global car market and 2.6% of global car sales, with internal combustion engine (ICE) vehicles comprising the balance. The need to reduce carbon-dioxide (CO2) emissions and comply with government regulations is pushing automakers to introduce 48-V mild-hybrid (MHEV) models. The range from hybrid to electric to energy independent is depicted in Figure 1. powertrain

Yet misconceptions and well-meaning loyalties to fully electric drivetrains persist. In this article, I’ll address five myths about MHEVs. 

Myth No. 1: The market cannot take any more segmentation with 48-V MHEVs.

The market already offers a variety of ICE alternatives in plug-in HEVs and battery EVs (BEVs) even when not all consumers are ready to give up ICE vehicles. Deloitte’s 2020 Global Automotive Consumer Study indicates that 10% of potential buyers in India and 43% of auto buyers in Germany are not willing to pay more for an EV. 48-V MHEVs are less likely to further fragment the market than they are to fulfill existing demand by addressing both range anxiety and cost concerns, and edge consumers closer to the electric future. 

Myth No. 2: OEMs will skip 48 V in their move toward EVs.

In their report, “Reboost: A Comprehensive View on the Changing Powertrain Component Market and How Suppliers Can Succeed,” consultants McKinsey & Co. estimated the need for a cumulative $50 billion investment in the EV charging infrastructure by 2030 (not including grid upgrades) to support the current growth trajectory of the plug-in HEV and battery-powered EV market. Most original equipment manufacturers (OEMs) are embracing 48-V systems because they require merely a step-change in vehicle architecture, whereas combustion-engine cars need expensive redesigns to become battery-powered EVs. 

48-V systems are gaining popularity at a time when the number of electrical subsystems is increasing, thus increasing the need for more power, along with greater environmental concerns and regulatory compliance pressures. 

With automotive suppliers expanding their MHEV portfolios, a growing number of OEMs have planned or launched MHEVs. 

Myth No. 3: 48-V systems will make cars more expensive.

Despite the higher cost of new components, including the additional battery, there are savings elsewhere, including:

  • Size and weight reduction in nearly 4 km of cabling and in wire harnesses because 48 V allows for smaller wire gage than that possible with 12 V.
  • Reduction in costs due to better efficiencies achieved with 48 V electric pumps, fans, power-steering racks and compressors.
  • Reduction in battery cost due to lower requirements compared with those from PHEVs and BEVs.
  • Downsizing potential; for example, replacing a six-cylinder engine with a smaller, lower-cost four-cylinder engine while maintaining performance. 

Moreover, it is possible to manage MHEV costs through design – from the lowest-cost P0 architectures, which run off the accessory belt, to tightly-integrated P4 architectures, where electric motors apply torque directly to the axle. 

While economies of scale can further offset upfront costs, MHEVs also lower the true cost to own by improving fuel efficiency, with features such as longer engine-off time during start/stop events, energy capture via recuperative or regenerative braking, and torque assist for the ICE engine. 

Myth No. 4: 48-V systems will replace 12-V systems.

MHEVs are likely to continue linking a conventional 12-V battery to the 48-V system through a DC/DC converter. In current designs, the 48-V system handles loads from climate control and torque assist and helps reduce startup times, while the 12-V system continues controlling the engine, controls the transmission, and handles active safety and infotainment functions, which minimizes redesign and the related costs.

Eventually, high-end vehicle manufacturers will switch to 48-V systems completely, but this will likely take 10 to 15 years. 


Bridging 12 V and 48 V in dual-battery automotive systems


Read the white paper

Myth No. 5: The world needs full EVs now.

Actually, the world needs to reduce CO2 emissions now, and regulations are finally beginning to effect change toward this goal. In 2021, the European Union will begin limiting CO2 emissions to 95 g/km, with plans to further limit them to 59 g/km or more by 2030. Countries including China, India, Canada and the U.K. have also announced targets to phase out ICE vehicles over the next couple of decades.

Although EVs are available for consumers willing and able to make the switch today, MHEVs offer a path of increasing the electrification of transportation. It is a path that helps address concerns about cost, range, and the environment while continuing to utilize both the existing economies of scale and customer expectations. Many carmakers and OEMs now have significant as well as growing 48V product portfolios.

Wherever you are on this path, whether you are designing an MHEV or an EV, we can help you at any level.

Additional resources