Lan Trieu Lam

Advanced design of valve-regulated lead-acid battery for hybrid electric vehicles

Abstract A novel design of lead–acid battery has been developed for use in hybrid electric vehicles (HEVs). The battery has current take-offs at both ends of each of the positive and negative plates. This feature markedly reduces battery operating temperatures, improves battery capacity, and extends cycle-life under HEV duty. The battery also performs well under partial-state-of-charge (PSoC)/fast-charge, electric-vehicle operation. The improvements in performance are attributed to more uniform utilization of the plate active-materials. The battery, combined with an internal-combustion engine and a new type of supercapacitor, will be used to power an HEV, which is being designed and constructed by an Australian industry–government consortium.

Understanding the mechanism by which bismuth improves lead-acid battery capacity

Abstract To elucidate the mechanism by which bismuth enhances the capacity of valve-regulated lead-acid (VRLA) batteries, model experiments are performed on pulverized positive electrodes produced either from leady oxide, which contains virtually no bismuth (termed ‘Bi-free oxide’), or from Pasminco VRLA Refined™ oxide, which is of high purity and contains a specified amount (0.05 wt.%) of bismuth. The electrodes are compressed under a range of pressures (1.4 to 60 kPa). Below 40 kPa, the presence of bismuth increases the initial capacity. At all pressures, bismuth enhances the rate at which the capacity develops during cycling. Reconnection of the separated agglomerates of lead dioxide is the key factor in restoring the capacity of the pulverized electrode. Electron micrographs reveal that there are two essential types of contact in the positive material: (i) ‘micro-contact’ between individual irregular-shaped or individual needle-like crystals, to form the agglomerates; (ii) ‘macro-contact’ between individual agglomerates, to form the skeleton of the positive mass. Bismuth encourages the growth of fine needle-like crystals on the surface of the agglomerates. These crystals spread out and inter-weld to form ‘bridges’ between the agglomerates and, thereby, consolidate the porous mass of the electrode. This influence of bismuth on morphology is considered to be responsible for the demonstrated improvements in capacity performance.

Capacity and cycle-life of batteries using bismuth-bearing oxide

Abstract An examination is made of the capacity performance of lead–acid positive electrodes which are prepared from bismuth (Bi)-bearing oxide. This oxide is produced from Pasminco VRLA Refined™ lead which contains 0.05 wt.% Bi. For comparison, benchmark tests are performed on electrodes made from oxide with virtually no bismuth (

Further demonstration of improved performance from lead-acid batteries manufactured with bismuth-bearing high-purity lead

Abstract This investigation examines the cycle-life of valve-regulated lead-acid (VRLA) batteries which have been fabricated either with the manufacturers own leady oxide (termed ‘factory oxide’) or with leady oxide prepared from Pasminco VRLA Refined™ lead (termed ‘VRLA Refined™ oxide’). VRLA Refined™ lead is a soft lead of high purity with a specified amount (0.05 wt.%) of bismuth. To provide a comparison of performance, benchmark tests are performed on batteries of equivalent design that have been supplied by two different manufacturers. Batteries made from factory oxide exhibit cycle-lives which exceed the minimum life specified by the Japanese Industrial Standard (JIS) test and by the International Electrotechnical Commission (IEC) test. Under the JIS procedure, the failure of both types of battery is due to expansion of the positive-plate material and subsequent extensive loss in connectivity between the constituent agglomerates of lead dioxide. By contrast, battery failure under the IEC procedure is caused by undercharging of the negative plates. The use of VRLA Refined™ oxide produces a marked improvement in battery cycle-life. Gains in performance from 675 to 800 cycles and from 510 to 675 cycles are obtained under JIS and IEC tests, respectively. It appears that the presence of bismuth at the specified level extends battery life by strengthening and increasing the connectivity in the positive-plate material (JIS test) or by raising the chargeability of negative plates (IEC test).

The Next Great Challenge for Valve-regulated Lead-Acid Batteries: High-rate Partial-state-of-charge Duty in New-generation Road Vehicles

Publisher Summary This chapter focuses on the challenge of high-rate partial-state-of-charge (HRPSoC) duty of valve-regulated lead–acid (VRLA) batteries in new-generation road vehicles. The new-generation vehicles require batteries to operate in a manner that is quite unlike the duty experienced by present 12 V automotive types that is starting, lighting, and ignition (SLI) types. In general, the battery will have to supply significant amounts of electrical energy for on-board electrical functions and, in several of the systems, will have to accommodate charge returned via regenerative braking as part of the scheme to save fuel. Under such duty, the battery will have to operate continuously at a partial-state-of-charge (PSoC) and accept charge at extremely high rates. In addition, high-rate discharge is necessary for engine cranking and power-assist. Overall, the battery is said to undergo HRPSoC duty. Lacking a construction that is purpose-designed for HRPSoC duty, VRLA batteries typically lose at least 50% of their initial capacity after operating in a simulated hybrid electric vehicle (HEV) for an equivalent service-life of around 32,000 km.

Towards sustainable road transport with the UltraBattery

Abstract There is strong interest in vehicles powered by batteries to mitigate carbon dioxide emissions and reduce oil consumption. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has developed the UltraBattery T M to provide the automotive market with a safe, efficient and affordable energy-storage device that meets the high-rate partial-state-of-charge (HRPSoC) duty required from hybrid electric vehicles (HEVs). The UltraBattery T M comprises a supercapacitor integrated with a lead–acid cell. The technology has been taken up by the Furukawa Battery Co., Ltd., Japan, and the East Penn Manufacturing Co., Inc., USA, and is under mass production for both HEV and renewable energy applications. This chapter reviews: (1) the early failure mechanism of conventional lead–acid batteries under the HRPSoC duty, and (2) the operating principles and the capability of the UltraBattery T M to overcome such failure. The UltraBattery T M is under evaluation by many carmakers worldwide, and it has been adopted in both the Honda Odyssey Absolute and the Honda StepWGN as original equipment.