P.T. Moseley

Progress in overcoming the failure modes peculiar to VRLA batteries

Abstract The results of an international collaborative program of research have shed new light on the mechanisms limiting the life of valve-regulated lead–acid (VRLA) batteries under different duty cycles. Management of the internal oxygen cycle is a central issue and improvements in materials selection and cell design show promise of significant extension in battery life.

Improving the valve-regulated lead–acid battery

Abstract This paper outlines some of the improvements in the performance of valve-regulated lead–acid (VRLA) batteries that have been accomplished during the course of the 1990s and considers further advancements which might be achievable. Attention is focused on those aspects of the battery that have been changed in order to convert the original, flooded (vented) design into a valve-regulated unit. Refinements of the components which were modified during the course of the flooded-valve-regulated conversion could be a productive endeavour as research workers strive to raise the life of the VRLA battery to match, and exceed, that of its flooded predecessor.

Positive plate additives

Approaches to the use of additives in pursuit of improved active material utilization in the positive plate of the lead/acid battery are reviewed. In order for the use of additives to lead to significant improvements in specific energy adequate provision must be made to support the stoichiometry of the discharge reaction and consideration must be given to the volume fraction occupied by candidate materials.

Gas sensing properties of the mixed molybdenum tungsten oxide, W0.9Mo0.1O3

The mixed oxide W 0.9 Mo 0.1 O 3 responds sensitively to oxidizing gases such as ozone and NOx in air and suffers only a mild interference from changes in relative humidity. The mixed oxide has a small activation energy for conduction (0.1 eV) and an unusual concentration dependence of response at low temperatures. Possible response mechanisms are considered.

Characteristics of a high-performance lead/acid battery for electric vehicles — an ALABC view

Abstract As the electric automobile at last becomes available to customers of the major automobile manufacturers, thedebate over what are the essential performance characteristics that will encourage large-scale electric vehicle (EV) penetration of the domestictransport sector continues unresolved. All are agreed that the EV battery is a key element in this consideration and, accordingly, thedevelopment of candidate batteries is currently proceeding at an unprecedented rate. This paper considers the several parameters that will influence strongly the purchase decision for EVs and proposes a simple methodology for rating the performance of candidatebatteries against a single benchmark. The progressive development of the valve-regulated lead/acid (VRLA) battery through the 1990s to meetthe required performance is then reviewed.

Gas-sensing properties of Ta-doped MoO3−x

During a search for alternative materials to replace tin(IV) oxide in semiconducting oxide gas sensors it has been found that sensors comprising sub-stoichiometric molybdenum trioxide exhibit promising characteristics.

Lead/acid battery myths

Abstract The lead/acid battery deserves a more positive image than has been traditional heretofore—particularly with respect to a number of aspects that relate to its utility as a power source for electric vehicles. Recent results from a large internationally coordinated research programme indicate that: (i) with proper attention to construction, valve-regulated lead/acid batteries can be deep-discharged many times without capacity loss; (ii) lead/acid batteries can be recharged extremely rapidly so that long journeys of electric vehicles become a realistic possibility; (iii) ranges of over 150 km between charges are achievable, and (iv) the introduction of significant numbers of lead/acid-powered electric vehicles does offer a beneficial environmental impact.

High-rate, valve-regulated lead–acid batteries — suitable for hybrid electric vehicles?1

Abstract The possibility of replacing, with electric drive systems, at least some of the internal-combustion engines currently employed in road vehicles is being actively pursued by all the worlds major automobile manufacturing companies. Minimum on-road emissions would be achieved by the adoption of pure electric vehicles, but the somewhat limited range available between charges of the batteries has led to a serious evaluation of hybrid electric vehicles as an acceptable compromise. In hybrids, a small internal-combustion engine, operated at high efficiency, will consume less fuel and produce less emissions than would a regular internal-combustion engine, and will allow considerable range extension over the pure electric vehicle. Eventually, an electric system which employs a fuel cell may become affordable. It is likely that all three systems — the pure electric, the hybrid electric, and the fuel cell system — will require battery support, particularly to provide boost power for acceleration and hill climbing. Although more expensive battery systems are being vigorously developed in pursuit of greater range per charge, the benchmark against which these systems are compared remains the valve-regulated lead–acid (VRLA) battery.

Progress in the Development of Lead-Acid Batteries for Hybrid Electric Vehicles

There is increasing interest, and indeed market growth, in hybrid electric vehicles, both for environmental and for economic operating reasons. However, the vast majority of hybrid vehicles currently on the road are powered by expensive nickel/metal hydride batteries. In order to maximize the benefits to be obtained by the introduction of these vehicles it is necessary to keep the cost attractive to the potential purchaser, so that fuel savings are not outweighed by increased purchase cost. Raw materials cost suggests that no major reduction in the cost of nickel batteries can be anticipated and thus considerable interest attaches to the possibility that batteries based on less expensive materials may be able to perform the necessary function, at least for medium and mild hybrids. The paper considers the work that has been done to overcome the problems associated with the use of lead-acid batteries in this application and describes some of the demonstration projects taking place in 2006

In pursuit of high specific energy, high specific power valve-regulated lead-acid batteries

This paper seeks to consolidate the experiences gained from a group of projects carried out by the Advanced Lead-Acid Battery Consortium (ALABC) and aimed at achieving increases in the specific energy and the specific power of lead-acid batteries by developing grid designs of low weight. The use of corrosion-resistant alloys allows significant reductions in weight, but if this approach is taken too far problems arise with obtaining good adhesion of the active material to the grid. Some success has been achieved in the production of cells with improved specific energy and long life.