Global automotive supplier Johnson Controls announced it has reduced a micro-hybrid battery pack from the size of a car trunk to the size of a shoebox, representing a significant breakthrough for the technology.
The newer, more advanced forms of micro-hybrid technology — in conjunction with smaller, cheaper battery packs – could help automakers in the US achieve the fuel efficiency standards known as Corporate Average Fuel Economy requirements.
Micro-hybrid vehicles, currently a mostly European trend, are most often associated with start-stop technology — the engine stops running when a vehicle is stopped, and restarts when the accelerator is pressed. That technology can be combined with regenerative braking, which allows a vehicle to recoup energy normally lost during the braking process, for even greater fuel savings.
Micro-hybrids are also seen by many in the industry as a more affordable alternative to full hybrids, which have a much larger lithium-ion or nickel-metal-hydride battery pack.
The Johnson Controls system consists of a 48-volt lithium-ion battery pack and an advanced low-voltage lead-acid battery that supports higher power loads and regenerative braking features.
A micro-hybrid system with an advanced, lead-acid 12-volt battery that allows for start-stop technology and the lithium-ion battery will improve fuel efficiency about 15 % when compared to a standard internal combustion engine. This is also better than the 8 % improvement of a start-stop system — on vehicles such as the Chevrolet Malibu and Ford Fusion — but less than that of a full hybrid, which can improve fuel efficiency by as much as 20 %.