Axion Power and ePower Engine Systems enter 5-year agreement for use of PbC batteries in diesel-electric drivetrains for Class 8 trucks; tests suggest up to 35% improvement in fuel economy
Axion Power International, Inc, the developer of advanced lead-carbon PbC batteries and energy storage systems (earlier post), has entered a strategic relationship with ePower Engine Systems LLC. ePower Engine Systems specializes in the retrofit and conversion of diesel-powered Class 8 trucks into series hybrid-powered units inspired by the diesel-electric drives in locomotives—i.e., the diesel engine powers a generator that in turn provides power directly to the traction motors.
ePower Engine Systems has consented to a five-year initial term with Axion Power that includes the exclusive use of Axion’s PbC batteries, and battery management systems in all ePower retrofits and conversions.
The first truck to be outfitted with a PbC battery string has been completed and is now on the road going through its final test procedures. The truck, a Peterbilt 386, was outfitted with 56 PbC batteries operating in a string configuration and incorporates Axion’s proprietary Battery Management System and data logger.
Our early testing has gone well and has demonstrated an ability to increase miles per gallon by more than 35%. We believe, and more importantly ePower believes, that with improved synergy of function between the proprietary hybrid drive train and our PbC batteries, that improvements in miles per gallon exceeding 50% can be achieved.
The extremely high charge acceptance of our batteries over thousands of cycles, combined with the inherent battery voltage equalization in large string applications, make the PbC battery a great value proposition in the ePower system.—Axion Chairman and CEO Thomas Granville
We have worked with several types of batteries, including advanced lead-acid batteries, and have come to the firm conclusion that even VRLA or glass-mat batteries are not capable of sustained performance in this demanding application for over-the-road transport. They start out meeting specification, but their performance degrades significantly, often, requiring a complete replacement within a matter of months.
The PbC batteries, on the other hand, are designed for sustained long-lasting performance geared for the life of our system, and the rigors of many charge/discharge cycles. The PbC batteries accept fast recharge so they are capable of taking full advantage of the regenerative braking functionality of our system. In addition, PbC batteries are competitively priced, and they have a construct with a proven safety record.—Andy Claypole, ePower Engine Systems CEO
PbC batteries use lead-acid technology enhanced by the complete replacement of the typical lead in the negative anode with Axion Power’s proprietary activated carbon material. This allows for simple manufacturing processes and smooth end-of-life recycling.
Granville emphasized that the hybrid drive train usage of PbC batteries is separate from, and in addition to, the use of PbC batteries for anti-idling purposes.
ePower. ePower Engine Systems has developed a diesel-electric series hybrid system inspired by current diesel-electric locomotive drive systems, and using off-the-shelf technology components. The core of ePower’s IP is how it controls the amount and delivery of the electricity from the AC generator to and from the electric motor and, when needed, the charging of and flow of electricity from the battery pack to the electric motor.
ePower showed its first converted truck—a Peterbilt 387—at the 2011 Mid-America Truck Show. The original drivetrain comprised a 485 hp diesel and a 10-speed transmission; the first-generation retrofit system used a 187 hp diesel as a generator, plus battery pack, and no transmission. Generator power is supplemented with battery under increased load—e.g., when accelerating or climbing. Batteries are recharged during coasting and braking.
At a 65 mph cruise, the system is designed to operate using generator power only.