Research Areas

ALABC's current research portfolio focuses on the design and demonstration of carbon-enhanced lead-acid batteries for hybrid electric vehicle duty. The current program is scheduled to run from January 2010-December 2012.

The task for the battery in a hybrid electric vehicle is particularly demanding as it is required to operate from a partial-state-of-charge so that regenerative braking energy can be accepted efficiently. From this base-line, the battery is called upon far more frequently than its SLI (starting, lighting an ignition) predecessor. Discharges and charge events typically involve only a small fraction of the battery’s capacity but they occur continuously and do take place at very high rates.

Conventional lead–acid batteries, such as those designed for SLI or deep-cycle use, quickly accumulate lead sulfate on the negative plate under such a regime and the first HEVs to appear have made use of nickel metal hydride batteries. Although these are somewhat more costly than lead–acid they are able to perform the duty without early failure.

Quite recently it has emerged that the incorporation of elevated levels of certain types of carbon into the negative plates of lead–acid batteries can overcome the mechanism that is responsible for the accumulation of lead sulfate and this discovery has allowed the production of prototype lead–acid batteries that are capable of operating successfully in the HEV mode.

Of all the energy storage systems that employ lead–acid chemistry, that which has so far been most successful in the HEV application has been the Ultra battery. This has a conventional PbO2 positive plate and a negative comprising two parts: one part has the usual sponge lead active material and the other part is a capacitor electrode containing a mixture of carbon black and activated carbon. The two parts of the negative share a common contact to the external circuit and they share the same positive plate. With this design, the total discharge or charge current of the combined negative plate is composed of two components: the capacitor current and the regular lead–acid negative plate current. Accordingly, the capacitor electrode can act as a buffer to share the discharge and charge currents with the lead–acid negative plate and protect it from being discharged and charged at high rates.

The success of this system is not limited to laboratory tests, where the Ultra has completed over 370,000 EUCAR cycles without failure. A Honda Insight fitted with a 144 V Ultra battery,has run for 100,000 miles with no conditioning and the battery remained in an excellent state throughout.

Hybrid Electric Vehicle demonstrations using lead–acid batteries during 2009.

In the U.S.A.:

1) Honda Civic hybrid with an Ultra battery (6.7 Ah, project DP1.8)

2. hybrid electric bus with a homogeneous high-carbon negative plate battery (50Ah project DP1.9).

In Europe:

1) Retro-fit plug-in hybrid delivery van (ADDZEV project)

2) Honda Civic hybrid with a bipolar battery (7 Ah DP1.7).