Introduction and widening of 48 V voltage system

CESA paper abstract

The maximum power needed for on-board vehicle electrical network has increased continuously, and might overtake the 10kW threshold in the near future (taking into account the energy recovering needs). Standard up to date 14V networks are uncapable of delivering such power needs.

After about 20 years of innovative works concerning the 42V onboard network, this solution was finally abandoned by most of the car manufacturers, substituted by the 48V network. The need to increase the onboard voltage level was initially motivated by the performances enhancement of Lead Acid Batteries systems. Nowadays the CO2 emissions reduction is also expected, thanks to the evolution of battery technologies (as example Li-ion chemistry). This strategy is then justified by increasing needs of electrical power, not compatible with standard 12V networks, as well as by energy recovering needs necessary for CO2 emissions optimization.

This paper will develop the expected scenarios for introduction and widening of the 48V technology in our vehicles, taking into account the 48V standard technical Specification issued from the initiative of the German OEMs, and the VDA help :
 - Define and set up the conditions for succeeding in the introduction of the 48V technology, firstly on Mild-Hybrid powertrain applications. 
- Then extend the 48V voltage as a second onboard network to allow future needs : 
High application rate on hybrid powertrain by 2020 
Optimization of Electrical energy management 
CO2 emissions reduction (48V storage system allowing high recovering performances) 
Potential opportunities of using 48V to supply some high power consumers, like electrical steering, air conditioning compressor, engine cooling fans, heated rear window, …). 

By El Khamis Kadiri and Franck Briault, PSA Peugeot Citroën