With growing concerns around air pollution, emission norms across the globe have only become stricter over the years. Today, every old internal combustion engine (ICE) vehicle is looked down upon by environmental conservationists and even authorities who are trying to curb down emission levels.
This led to the advent of electrified powertrains including fully-electric and hybrid power mills. Manufacturers across the globe have found hybrid powertrains as the perfect solution to stricter emission standards which help curb emission of particulate matter into the air. Hybrids can be broadly classified into three types: mild, strong, and plug-in.
Mild hybrids are the most basic and common type of hybrid powertrains in use today, particularly in cars. Hence, it is also the most cost-effective solution used to overcome the challenges pertaining to fuel efficiency and emission norms. Today, a mild-hybrid powertrain has become more of a necessity than a convenience over a period of time.
In fact, mild-hybrids have also evolved since their inception around one and a half decade ago, with OEMs introducing newer technologies that optimise both fuel efficiency and performance of regular ICE cars. Initially, mild-hybrids used 12V batteries but gradually OEMs are switching to a more powerful 48V setup. Audi, General Motors, and Volvo were the initial adopters of a 48V mild-hybrid setup followed by Hyundai, Kia, Mercedes-Benz, Ford, Toyota, Suzuki, and others.
Mild-hybrid evolution: Why switch from 12V to 48V?
With the growing automotive landscape, the needs of a modern car have also changed with time. The 12V setup is a basic electrified system used initially to power car accessories only and later offered engine start/stop functionality. It usually comprises a 12V lithium-ion battery that is coupled with a belt-driven starter generator whose power output is limited to typically around 3.5 kilowatts.
In comparison, a 48V setup is far more advanced to fulfill the requirements of modern cars that are loaded to the gills with convenience and safety features. A typical 48V system comprises a 48V lithium-ion battery, an electric motor/generator (often an Integrated Starter Generator or ISG), and a DC/DC converter.
This dual-voltage setup is crucial, as the DC/DC converter steps down the 48V power to 12V for traditional vehicle systems like lighting and infotainment, allowing automakers to leverage the benefits of higher voltage for power-hungry components while maintaining compatibility with existing 12V accessories.
Higher Power Requirements of Modern Vehicles
Features like advanced driver-assistance systems (ADAS), sophisticated infotainment systems, active suspension, electric power steering, electric superchargers/turbochargers, etc, have become a common thing in today’s cars. A 12V system struggles to adequately power all these components without requiring very high currents.
The 48V system can provide substantially higher power — typically between 15 to 20 kW and even up to 50 kW in some cases — while requiring only a quarter of the current compared to a 12V system for the same output. This significant reduction in current enables the use of smaller, lighter, and more economical wiring, lowering costs and improving energy efficiency. By increasing the voltage from 12V to 48V, the current demand decreases fourfold, resulting in significantly lower resistive losses and enhanced overall system performance.
Improved Efficiency & Reduced Losses
48V systems offer enhanced efficiency and reduced energy losses in vehicles. They enable the use of thinner, lighter wiring due to lower current requirements, which reduces vehicle weight, manufacturing costs, and improves performance. Reduced current also leads to lower heat generation, increasing overall efficiency and minimizing the need for complex cooling systems.
Additionally, 48V systems improve regenerative braking by more effectively capturing kinetic energy during deceleration and storing it in the battery. This recovered energy can assist the engine or power vehicle accessories, further boosting fuel economy.
Performance boost at low cost
48V systems play a key role in enabling cost-effective mild hybrid technology. They provide an affordable path to vehicle electrification, helping automakers meet stricter emission norms without the higher costs of full hybrids or EVs. These systems enhance start-stop functionality by allowing smoother engine shutdowns during idling, thereby improving fuel efficiency and lowering emissions.
Additionally, the 48V electric motor can deliver torque assist during acceleration, boosting performance and reducing the strain on the internal combustion engine. This balance of performance, efficiency, and affordability makes 48V systems ideal for mild hybrid powertrains.
Future-Proofing for further Electrification
The 48V electrical architecture offers a scalable and future-ready platform for advancing vehicle electrification. It provides a stronger foundation for integrating more sophisticated electrical components, paving the way for a gradual shift toward higher levels of electrification. Additionally, as vehicles adopt more autonomous and connected technologies, power demands for systems like computing, sensors, and communication will rise.
The 48V system is well-suited to support these higher auxiliary loads, ensuring vehicles can meet future technological requirements efficiently. This makes 48V systems an essential step in preparing vehicles for evolving power and performance needs.
