As pointed out by Kia and other partners, these batteries were chosen for this particular hybrid application because of:

1. their performance in high-rate partial state-of-charge operation;
2. their ability to operate in sub-freezing temperatures;
3. the lack of need for an active battery cooling system;
4. their cost advantages over lithium-ion batteries; and
5. their high recyclability rate.

The latest lead-carbon battery designs can operate between 30 to 70% state-of-charge at 12.5kW, which seems to be the target rate for micro/mild hybrid electric vehicle duty. Additionally, as with conventional SLI (starting-lighting-ignition) batteries, advanced lead-carbon batteries can be used at temperatures as low as minus 30°C (-22°F), which is currently not possible with lithium-ion batteries, but is an essential requirement for vehicles used in the snow-belt areas of the northern United States, Europe and various parts of Asia. Lead-carbon batteries also differ from lithium-ion in that they require no active cooling and no expensive battery management system at a cell level.

As with all lead-acid batteries, the cost-to-performance ratio provides high production value that is already well-known to automotive manufacturers, and despite their relative enhancements, lead-carbon offers cost advantages that are still significantly lower than other battery chemistries. Finally, lead-carbon batteries, like all lead-acid batteries, have a recycling rate of 99% in North America and Europe.

The concept of 48-volt mild hybrid powertrains is drawing quite a bit of attention from automakers because they are working diligently to lower CO₂ emissions by increased electrification of the powertrain as opportunities for achieving still more fuel efficient engines diminish. The problem is, while needing to reduce emissions, it is necessary to keep production at a relatively low cost. Right now, we believe the best way to achieve that is with a modified micro/mild-hybrid powertrain powered by advanced lead-carbon batteries.

—ALABC European project coordinator Allan Cooper

The three vehicles in the ALABC’s 48V hybrid display included the following:

• The 48V LC SuperHybrid. (Earlier post.) Project Partners: ALABC, Controlled Power Technologies (CPT), Valeo, AVL Schrick, Provector, Mubea, and the University of Sheffield)
  Earlier conceptualized in a 12-volt architecture, this micro/mild hybrid is also based on a gasoline-powered, turbo-charged 1.4 TSI Volkswagen Passat and enhanced with a Valeo electric supercharger and a CPT integrated starter generator (ISG) both powered by Exide Orbital lead-carbon batteries to enhance performance, extend mileage and lower emissions at an affordable cost.

  The 48V demonstrator differs from the 12V design by offering additional functionality including torque assist to the engine for enhanced launch and acceleration, optimized cruise conditions, and the ability to harvest significantly more kinetic energy from regenerative braking. While the vehicle is still undergoing enhanced calibration, initial results indicate a 13% CO₂ reduction over the base car and simulation indicates a possible extra 5% reduction over the NEDC cycle. This was the ALABC’s first 48V demonstration, and it has drawn considerable attention from OEMs.

• The 48V Kia Optima T-Hybrid. (Earlier post.) Project Partners: ALABC, Hyundai Motor Group, AVL Schrick, Valeo, and East Penn Manufacturing
  Loosely-based on the 48V LC SuperHybrid, this concept vehicle is powered by the Optima’s existing 1.7 liter CRDi turbo-diesel engine, paired with a Valeo 10 kW electric starter generator and electric supercharger powered by a 48V version of East Penn’s lead-carbon UltraBattery. The diesel-electric powertrain concept enables the T-Hybrid (turbo-hybrid) to be driven in electric-only mode at low speeds and when cruising, with deceleration serving to recharge the battery pack. It includes start-stop functionality and regenerative braking, but also provides the enhanced power and torque at low speeds that made the aforementioned LC SuperHybrid so popular in test drives.

  During the conference session on 28 Jan., Ulf Stenzel, Lead Engineer New Battery Technologies – Hybrid & Electric Powertrain Systems at AVL Schrick, provided an overview of the battery and powertrain technology used in the 48V Kia mild-hybrid system and a brief summary of the achieved results.

• The ADEPT 48V. (Earlier post.) Project Partners: ALABC, Ford Motor Company, Ricardo, CPT, Provector, Faurecia, the University of Nottingham, and the University of Sheffield
  The ADEPT (Advanced Diesel Electric Powertrain) combines low-cost, micro/mild hybrid technologies similar to those in the LCSH with a high degree of synergy to reduce current class-leading C-segment CO₂ emissions by an additional 15-20%. Based on a Ford Focus, this vehicle is projected to cut CO₂ levels to 75g/km while indicating a pathway to 70g/km at a cost/emissions reduction ratio superior to a full-hybrid solution.

  The system includes regen braking and other efficiency improvements for optimized oil flow and pressure control, as well as a 48V electric turbine that captures exhaust waste heat for conversion to additional recovered electrical energy. However, unlike the other two cars, it does not have an electric supercharger but will rely solely on the starter/generator for initial torque assist on the engine.

The ALABC and its member companies have worked for more than 20 years to bring lead-carbon technology from the laboratory to the marketplace. Companies such as East Penn Manufacturing, Moura, Energy Power Systems, Exide (Europe), FIAMM, and Shin Kobe are all working on various lead-acid and lead-carbon technologies for 48V automotive applications, and many are participating in ALABC projects to enhance these batteries and prove their viability in the emerging 48V marketplace.

Some of the support for the Kia Project was obtained through special funding from ALABC members including the RSR Corporation, the Doe Run Company, Teck Metals, Acumuladores Moura, Britannia Refined Metals, and an anonymous metals trader.

The Advanced Lead Acid Battery Consortium is an international research cooperative comprised of lead producers, battery manufacturers, equipment suppliers, and research facilities organized to enhance the performance of lead-acid batteries for a variety of markets, including hybrid electric vehicle (HEV) applications, renewable applications, and various other energy storage systems.

Founded in 1992 as a program of the International Lead Zinc Research Organization (ILZRO), the ALABC pools the resources of its global membership in order to perform specific research on advanced lead-acid batteries that otherwise would not be possible by any single entity.