If hybrid electric vehicles (HEVs) are to contribute to reductions in pollution and greenhouse gas emissions, and to relieving the pressure on world oil supplies, they must be adopted in very large numbers, and hence must be affordable. Such an eventuality may be reached if a massive new industry, manufacturing large lithium-based batteries can be built up, and the cost of such batteries drawn down. An alternative, or perhaps additional, route to the launch of large numbers of HEVs is possible if batteries based on lead-acid chemistry (surely the least cost option) can perform the HEV function. The crux of the challenge for lead-acid has been that neither conventional 12 V SLI batteries nor present generation deep-cycle batteries are able to carry out the required duty. Batteries for HEV systems operate from a partial-state-of-charge baseline and are discharged, and particularly re-charged, at extraordinarily high rates (albeit within a small range of state of-charge). Within such duty, the life-limiting mechanism for lead-acid appears to involve the progressive accumulation of lead sulfate on the negative plate. This failure mode appears as a result of the very high rates of recharge and persists because the battery is not routinely returned to a full state-of-charge in the required duty. Partial-state of-charge operation does bring one benefit, however, in that, at intermediate states-of charge, charge-acceptance can be extremely high. In order to offer an acceptable life in such applications, conventional designs of VRLA batteries must be revised. The battery must be able to sustain the negative plate charge reaction at very high rates, overcoming diffusion limitations (leading to reduced lead sulphate solubility etc.) which would otherwise lead to the onset of secondary reactions, such as hydrogen evolution, and charge inefficiency. There are two straightforward design modifications that offer the potential to redeem this situation and to allow the lead-acid battery to perform successfully in the high-rate partial-state-of-charge (HRPSoC) routine demanded in hybrid electric vehicles. The provision of an appropriate grid design allows the plates in the battery to accept the high charge rates required; and the incorporation of elevated concentrations of carbon (a few wt% instead of the traditional 0.2 wt%) alleviates the tendency for sulfate to accumulate, and appears to offer the route to a long operating life in the HRPSoC regime. This paper provides an early indication of the successful operation of lead-acid batteries that incorporate these features, both in the laboratory and in hybrid electric vehicles on the road.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    The operation of purpose-designed lead-acid batteries in power-assist hybrids


    Additional title:

    Das Betriebsverhalten von anwendungsangepaßten Bleisäurebatterien für Hybridfahrzeugen mit Energiemanagement


    Contributors:
    Moseley, P.T. (author) / Cooper, A. (author) / Kellaway, M.J. (author)


    Publication date :

    2007


    Size :

    9 Seiten, 7 Bilder, 2 Tabellen, 9 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    VRLA batteries match the performance of NiMH batteries in power-assist hybrids

    Cooper,A. / Moseley,P.T. / European Advanced Lead-Acid Battery Consortium,GB | Automotive engineering | 2008



    Lead-Acid Batteries

    India Lead Zinc Information Centre / Australian Lead Development Association, Melbourne / Lead Development Association | TIBKAT | 1977


    Lead-acid batteries

    Bullock, K.R. | Online Contents | 1994