Are 48V electrical systems the gateway to the vehicles of the future?

As vehicle technology progresses, so too does the vehicle’s appetite for electrical power.

In 1918, enabled by the fitment of a new six-volt positive-ground electrical system, the Hudson Motor Car Company became the first volume motor manufacturer to offer a self-starter.

This 6V system produced enough energy to power other ancillaries such as windscreen wipers, turn signals and lights until the early 1960s, when radios, demisters, and other power-sapping features again stretched the system to its limit – leading to the introduction of a more powerful 12V system.

Still, such is the pace of development that a mere 35 years later, the 12V system was again coming under pressure. So, after a brief flirtation with 42V in the early 2000s, the power is once again being stepped up – this time to 48V.

48V’s role in the short-term future of cars

Unlike earlier electrical systems the new dual (for now) 12/48V electrical system not only has to meet the demands of comfort and chassis systems, it is also expected to support the mission-critical functionality of current and future advanced driver assistance and autonomous driving systems.

While the mass rollout of Level 4 and 5 automated driving functionality is not expected before the mid-to-late 2020s, these systems will require more power alone than the 12V system can supply.

The higher voltage also carries the added benefit that the current draw is only 25 percent of that of a 12V system, which allows manufacturers to reduce the cross sectional area of the wire and thus the mass and cost of the harness.

Crucially, this relationship between power and current and voltage also supports manufacturers’ efforts to comply with ever-tightening emissions regulations.

The increase in available power from the 48V system, while remaining below the safety threshold of 60V, allows manufacturers to mildly electrify powertrains and in so doing create the 48V Mild Hybrid EV (MHEV).

Under real-world driving conditions, even the simplest architecture – a belt starter generator arranged in a P0 topology – is capable of significant energy recovery under deceleration, and torque boost during acceleration, thereby reducing fuel consumption and CO2 emissions.

This is of particular importance to manufacturers seeking to meet the 2020/2021 EU emissions update in a market where diesel powered passenger vehicles are rapidly losing favor. A gasoline-powered 48V MHEV is the ideal replacement for diesel power – achieving similar GHG emissions at a competitive price to the consumer.

What’s more, following the MHEV route allows manufacturers to scale the technology cost effectively to achieve the desired emissions savings.

But this, the very reason the technology is being considered by many manufacturers, may also be the reason why the architecture needs to continue to evolve beyond increased electrical power supply and mild electrification to ensure it retains its role as the gateway to future cars.

While the 48V MHEV certainly is a cost effective, easy to implement countermeasure to tightening emissions regulations across the globe, it still retains the source of the pollution – the ICE.

Regulations that could influence 48V’s role in the future of the car

In the EU, regulators are going to cut emissions to 59.4g/km, or 37.5 percent of the 2021 targets, by 2030.
After discussions with several industry insiders, Luca Ciferri, associate publisher and editor at Automotive News Europe, wrote in a March 2019 article that the industry largely agreed that only full EVs and plug-in hybrid EVs would meet these targets.

With several studies, such as that carried out by Navigant Research, which sees global sales of light duty SSVs and MHEVs exceeding 61 million by 2025, with about 15 percent of these featuring 48V, predicting that 48V-equipped vehicles will occupy a significant share of the market from about the second half of the 2020s, this change in regulation could prove to be a body blow. Manufacturers may be forced to go for high voltage full-time EVs or PHEVs instead of 48MHEVs to achieve the emissions targets.

Developments in the world's largest car market: China

At the same time, in China, where EV sales have seen unprecedented growth largely due to government subsidies, a cut in NEV incentives may also have a long-term impact on the development of 48V technology.

In March 2019, the Chinese government slashed subsidies for EVs and plug-in hybrids by 50 percent and barred provincial governments from subsidizing local purchases of the vehicles; a move largely considered to be the cause of the slump in EV sales in May. Without incentives EVs are just not affordable for the average Chinese consumer.

The impact of this initial cut in incentives can be seen in the drop in sales of EVs. With the EV and PHEV market growing 110 percent, to nearly 300,000 units, in the first quarter of 2019, sales rose a further 18 percent in April before crashing in May. For the first time since the introduction of the NEV program, sales edged up only 1.8 percent from a year earlier.
The problem with the drop in EV sales is that the Chinese government is still faced with a pressing air pollution problem that needs a solution; one that will hopefully continue to promote the NEV program.

For both the EU and China the evolution of the 48V MHEV into a low-voltage, low-power, full-time EV could be a solution that opens up a gateway to a new niche of clean low-cost future EVs.

Securing 48V’s role as the gateway to the car of the future

One such solution, Valeo’s 48V all-electric Double 100 prototype, made its world début at CES 2018, before being shown again at the 2019 Shanghai Auto Show with an updated design.

The 48V all-electric demonstration car was originally developed in partnership with Shanghai Jiao Tong University and claims to be:

• A smart solution, ideally suited to urban mobility with a top speed of 100km/h and range of 100km – the version shown in 2019 had an extended range of 150km
• A unique low-voltage electric solution that can be charged via any power socket or EV charger
• Approximately 20 percent more economical than existing high-voltage solutions – largely because it can do without some of the components and systems that high-voltage systems require to ensure user safety
  Pricing for this small 48V all-electric car could be as low as USD$9,000.

While other companies, such as Mahle and Oerlikon Graziano, are also working on 48V full-time EVs, Valeo’s low-cost solution could well give additional momentum to the electrification revolution whilst reinforcing 48V’s claim to be the gateway to the vehicle of the future.

• Interested in the 48V future of vehicles? Automotive IQ's Automotive 48V Power Supply Systems conference takes place in Berlin, Germany, from 11-14 November. For details on all of our conferences, check out the Events page