Healthy disagreement on 48V mild hybrids

The end game with the 48V hybrid cars that will first appear in volume production in 2017 is having no 12V battery - just a beefy 48V one. Continental said in a recent presentation that at least 20 years will pass before that happens but some car companies and academics talk of only a few years. Some players see the 48V battery being advanced lead acid while others pitch lithium-ion. CAEC proposes that even the 12V battery will be lithium ion.

 

In general, there is healthy disagreement about these powerful new concepts and that also includes the market potential. Most agree that sales will be huge eventually, replacing most conventional car production not grabbed by EVs.

 

Not yet in volume production, this 48V mild hybrid system with its reversible torque assist motor generator will make a major contribution to meeting the planned tighter emissions regulations for on-road vehicles worldwide. In the decade 2016-2026 and maybe to 2031, it may make a bigger contribution than strong hybrid and pure electric vehicles combined. It is the subject of the new IDTechEx report, Mild Hybrid 48V Vehicles 2016-2031

 

48V mild hybrids will be 50-75% cheaper than full (strong) hybrids according to Valeo. Hyundai estimates 75% cheaper, yet the flow of new strong hybrid models has become a rush so who is right? 48V devices and interconnects are smaller and lighter eg wiring harnesses - four times the voltage means the current reduced by a magnitude of four, so wire diameter can be reduced or Cu replaced with cheaper Al according to some but not others. A secondary benefit is improving performance and pleasure more easily and affordably than by EV. This secondary benefit gives such things as improved acceleration, ride (active suspension), quietness (engine downsized/ down-speeded, silent pure electric take-off, silent stop-start).

Reversing rotating machines used in 48V systems are multifunctional developments of the electric motor and alternator.

Operational modes are typically:

 

 

Generator

Recuperation

Boost

Engine start

Electric drive for a brief period from start

Design priorities are typically:

Reduced fuel consumption

Low integration effort (space, cost) giving advantage over full hybridisation

Continuous power supply

 

Jaguar Land Rover devices in a cooperative 48V mild hybrid project to take an Evoque to sub 100g CO2/km are shown below. Partners include Valeo, Raicam, Lotus and AP.