Performance Of Valve-regulated Lead-acid Batteries Research Articles

Hydrogen evolution behavior of electrochemically active carbon modified with indium and its effects on the cycle performance of valve-regulated lead-acid batteries

Electrochemically active carbon (EAC) was modified with In and In(OH)3 respectively. Its properties were characterized by TEM, EDS and XRD, and its hydrogen evolution behaviour and effects on the cycle life of valve-regulated lead-acid (VRLA) batteries were investigated. The study found that the modification of EAC with In or In(OH)3 did not significantly influence the crystal structure and surface morphology of EAC, but it can effectively increase the overpotential of hydrogen evolution and decrease the evolution rate of hydrogen on EAC. It is also observed that the addition of EAC modified with an appropriate amount of In or In(OH)3 in the negative plates of VRLA batteries can remarkably decrease the evolution rate of hydrogen and prolong the cycle life of batteries under high-rate partial-state-of-charge conditions. Moreover, in comparison with EAC modified with In, EAC modified with In(OH)3 showed better performance in terms of the improved cycle life of batteries.

Effects of electrochemically active carbon and indium (III) oxide in negative plates on cycle performance of valve-regulated lead-acid batteries during high-rate partial-state-of-charge operation

In order to inhibit sulfation and hydrogen evolution of the negative plates and to prolong the cycle life of valve-regulated lead-acid batteries for hybrid-electric vehicles, electrochemically active carbon (EAC) and Indium (III) oxide (In2O3) are added into negative active materials of valve-regulated lead-acid batteries. The influences of EAC and In2O3 on the cycle performance of valve-regulated lead-acid batteries are investigated under high-rate partial-state-of-charge conditions. Experiment results indicate that addition of EAC in negative active materials can prolong the high-rate partial-state-of-charge cycle performance of valve-regulated lead-acid batteries, whilst it results in the accelerated evolution rate of hydrogen during charge process. It is also observed that EAC with an appropriate amount of In2O3 can effectively increase the overpotential of hydrogen evolution, which can not only produce the decreased hydrogen evolution rate and promote conversion of PbSO4 to Pb in capacity recovery process, but also prolong the high-rate partial-state-of-charge cycle life of valve-regulated lead-acid batteries. The battery added with 0.5% EAC and 0.02% In2O3 in negative active materials exhibits at least four times longer cycle life than that without In2O3.

Essential characteristics for separators in valve-regulated lead–acid batteries

The absorptive separator plays an important role in the operation of valve-regulated lead–acid (VRLA) batteries. The composition and physical characteristics of recombinant-battery separator mats (RBSMs), also known as absorptive-glass mats (AGMs), directly affect three critical factors associated with the performance of VRLA batteries. The factors are: electrolyte supply, oxygen-transport, and constraint of positive active-material growth. This paper discusses the influence of the physical properties of RBSMs on the performance of VRLAs, explains how these properties are measured, and defines the characteristics of an ideal separator. Separators used presently in VRLAs meet some of these criteria, but development of advanced materials is required to improve battery life.

Performance of valve-regulated lead-acid batteries in real-world stationary applications — utility installations

A multi-phase project to investigate the reliability of valve-regulated lead-acid (VRLA) batteries in the field has been conducted by US industry and government research organizations. The focus of the study has been to characterize the relationships between VRLA technologies, service conditions, performance, and field failures. Two surveys were conducted: one of VRLA end users, and the other of VRLA manufacturers. Data from end users were obtained for over 56,000 telecom and utility installations representing over 740,000 cells. Seven manufacturers participated in the study. Preliminary correlations between utility end-user data, manufacturer information, and battery reliability have been developed and will be reported. Data for telecommunications installations will be reported in a separate publication when completed.

96/06457 An improved equation for the overall heat transfer coefficient in packed beds

In order to inhibit sulfation and hydrogen evolution of the negative plates and to prolong the cycle life of valve-regulated lead-acid batteries for hybrid-electric vehicles, electrochemically active carbon (EAC) and Indium (III) oxide (In2O3) are added into negative active materials of valve-regulated lead-acid batteries. The influences of EAC and In2O3 on the cycle performance of valve-regulated lead-acid batteries are investigated under high-rate partial-state-of-charge conditions. Experiment results indicate that addition of EAC in negative active materials can prolong the high-rate partial-state-of-charge cycle performance of valve-regulated lead-acid batteries, whilst it results in the accelerated evolution rate of hydrogen during charge process. It is also observed that EAC with an appropriate amount of In2O3 can effectively increase the overpotential of hydrogen evolution, which can not only produce the decreased hydrogen evolution rate and promote conversion of PbSO4 to Pb in capacity recovery process, but also prolong the high-rate partial-state-of-charge cycle life of valve-regulated lead-acid batteries. The battery added with 0.5% EAC and 0.02% In2O3 in negative active materials exhibits at least four times longer cycle life than that without In2O3.

96/06127 Lead/acid battery myths

In order to inhibit sulfation and hydrogen evolution of the negative plates and to prolong the cycle life of valve-regulated lead-acid batteries for hybrid-electric vehicles, electrochemically active carbon (EAC) and Indium (III) oxide (In2O3) are added into negative active materials of valve-regulated lead-acid batteries. The influences of EAC and In2O3 on the cycle performance of valve-regulated lead-acid batteries are investigated under high-rate partial-state-of-charge conditions. Experiment results indicate that addition of EAC in negative active materials can prolong the high-rate partial-state-of-charge cycle performance of valve-regulated lead-acid batteries, whilst it results in the accelerated evolution rate of hydrogen during charge process. It is also observed that EAC with an appropriate amount of In2O3 can effectively increase the overpotential of hydrogen evolution, which can not only produce the decreased hydrogen evolution rate and promote conversion of PbSO4 to Pb in capacity recovery process, but also prolong the high-rate partial-state-of-charge cycle life of valve-regulated lead-acid batteries. The battery added with 0.5% EAC and 0.02% In2O3 in negative active materials exhibits at least four times longer cycle life than that without In2O3.

Valve-regulated lead/acid batteries: they are not all the same!

It has become popular and widespread, both in symposia and battery magazine articles, to refer to valve-regulated lead/acid (VRLA) batteries as if they are a single entity and generic in nature. Sweeping conclusions have been drawn about the reliability and life of VRLA batteries but, usually, little is published alongside of these conclusions that can give the reader much insight into the nature of the alleged non-reliability, or indeed the failure modes associated with the apparent shortage of life. Consequently, there is a danger that the performance of VRLA batteries will become branded as a serious problem. The purpose of this paper is to present facts which demonstrate that VRLA batteries are most certainly not generic in nature. The batteries are designed differently, and they are manufactured in different ways from different materials. Moreover, the various producers make different claims with respect to the likely service-lives of VRLA batteries. When considered against this background, it should not be surprising that there is considerable variation in the life of VRLA batteries in their many and varied applications and environments. Nor should conclusions be drawn about all VRLA batteries by a consideration of a few.