Negative Plate Of Lead-acid Battery Research Articles

Addition of activated carbon fiber in the negative plate of lead-acid battery: Effect on the electrochemical and electrical performance

Addition of activated carbon fiber in the negative plate of lead-acid battery: Effect on the electrochemical and electrical performance

Positive Effects of Highly Graphitized Porous Carbon Loaded with PbO on Cycle Performance of Negative Plates of Lead-Acid Batteries

Carbon materials are one of the most important additives used in lead-acid batteries (LABs) to solve irreversible sulfation. Being the next generation additive for LABs, they exhibit more excellent performance. The addition of carbon materials to negative active material (NAM) is used to enhance the performance of batteries. In this paper, the composite of lead oxide and carbon (LC) was prepared by the pyrolysis of a mixture of highly graphitized porous carbon (HPC) and PbCO3. Compared with the control cell, the initial specific discharge capacity was increased by 16.5% when LC material was added to NAM. Finally, a possible mechanism for the improvement of the cycle performance of LC cell was proposed. The adoption of LC material can eliminate the difference in density between Pb and C, and thus make them evenly mixed. The uniformly dispersed HPC can promote electrolyte circulation and effectively limit the overgrowth of irreversible PbSO4. At the same time, the presence of -Pb-COO chemical bond can strengthen the stability of lead-carbon electrodes.

In-situ synthesis of novel nanostructured Pb@C composites for improving the performance of lead-acid batteries under high-rate partial-state-of-charge operation

The addition of carbon or carbon composite materials to the negative plate of lead-acid battery could effectively improve the battery electrochemical performance. Herein, a novel Pb@C nanocomposites are in-situ prepared by pyrolysis lead acetate impregnated glucose gel at nitrogen atmosphere. While the Pb@C nanocomposites is used as the additive adding in the negative active materials (NAM) of lead-acid batteries, which can great enhance the utilization of NAM. The negative plate, containing 1 wt.% Pb@C, owns the high affinity between the NAM and Pb@C material, which shows the best cycle-life (8921 cycles) performance on high-rate partial-state-of-charge (HRPSoC) and the highest of initial discharge specific capacity (165.1 mAh g−1). Moreover, the lower polarizability and more stable rate capability of the lead-acid cells contain Pb@C compare with blank cell. Besides, accelerate the diffusion of electrolyte and PbSO4 dissolution, due to the Pb@C materials form porous-skeleton with NAM in the negative plate. In summary, the Pb@C nanocomposites have potential to be used to enhance the specific capacity and HRPSoC cycle-life of lead-acid batteries.

Synthesis and characterisation of tribasic lead sulphate as the negative active material of lead-acid battery

Although tribasic lead sulphate (3BS) has been chemically prepared and found in the cured negative plates of lead-acid batteries (LABs), little was known about its behaviour if it is used directly as their negative active material (NAM). Here, we report a much more facile and energy-saving route to prepare phase pure 3BS powders: after β-PbO is reacted with PbSO4 at 30 °C, elongated 3BS plates of 4~8 μm in length, 1~3 μm in width and 0.1~0.2 μm in thickness are obtained in 4 h. Compared with electrodes prepared from β-PbO, α-PbO and leady oxide, the as-prepared 3BS electrode shows much better performance, which discharges more than 90 at 120 mA g−1 within 100 cycles of 100% DOD (depth of discharge) in a flooded cell. Therefore, 3BS can be used directly as NAM of LABs. It is also worth to notice that using 3BS can reduce the curing/drying time of the plates, thus save energy and produce uniformity in LAB production.

Lead oxide/carbon black composites prepared with a new pyrolysis-pickling method and their effects on the high-rate partial-state-of-charge performance of lead-acid batteries

A new pyrolysis-pickling method was developed to prepare various lead oxide (PbO)/carbon black (CB) composites as the additives in the negative plates of lead-acid batteries to improve their high-rate partial-state-of-charge (HRPSoC) performance. Compared with CB, the PbO/CB composites prepared by the pyrolysis-pickling method have higher content of alkaline surface functional groups (Calkaline) and less content of carboxyl surface functional groups (CCOOH) on CB particles which are still covered with small amount of PbO, meanwhile they have smaller BET surface area, but larger pore volume and average pore width. The hydrogen evolution process in the negative plates containing the PbO/CB composites is inhibited effectively due to the increased Calkaline on CB, while the redox processes (Pb↔PbSO4) in these negative plates are accelerated obviously owing to the changes in their microstructure. The PbO/CB composites can impede the growth of PbSO4 crystals and significantly increase the HRPSoC cycle life of the simulated test cells. In general, the PbO/CB composites with a lower PbO content may be the appropriate additives for the negative plate of lead-acid batteries.

The Effect of Surfactants on the Efficiency of Lead Acid Batteries

The aim of this study is to show the effect of two phosphonate surfactants (PS) on the electrochemical behavior of the negative plate of lead-acid battery in the sulfuric acid medium. The characterization of the electrode interface was investigated at room temperature by a set of electrochemical techniques as linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Scanning electron microscopy (SEM) was employed to determine the film layer's morphology deposited on the surface of working electrodes, in the presence and in the absence of the PS. When the PS was added in the acidic solution, hydrogen evolution became higher, the over-potential of hydrogen was shifted to negatives values and the growth of the anodic β-PbO2 was inhibited. SEM imaging with the presence of PS showed reduction in the growth of the anodic β-PbO2 and PbSO4 layers. EIS results indicate the decrease of the conductivity of β-PbO2 film on the lead surface electrode. The result of the CV, show a decrease in the peak related to transition of PbO to Pb demonstrates that lower PbO has been formed underneath the lead sulfate membrane in the presence of low concentration of SP indeed a decrease in the amount of formed PbSO4 on the electrode surface.

An in situ generated carbon as integrated conductive additive for hierarchical negative plate of lead-acid battery

In this work, we report an in situ generated carbon from sugar as additive in the Negative Active Mass (NAM) which enhances the charge–discharge characteristics of the lead-acid cells. In situ formed sugar derived carbon (SDC) with leady oxide (LO) provides a conductive network and excellent protection against NAM irreversible lead sulfation. The effect of SDC and carbon black (CB) added negative plates are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), galvanostatic charge–discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. The results show that subtle changes in the addition of carbon to NAM led to subsequent changes on the performance during partial-state-of-charge (PSoC) operations in lead-acid cells. Furthermore, SDC added cells exhibit remarkable improvement in the rate capability, active material utilization, cycle performance and charge acceptance compared to that of the conventional CB added cells. The impact of SDC with LO at various synthesis conditions on the electrochemical performance of the negative plate is studied systematically.

Design of an Online Maintenance Device for Batteries

In this paper, the sulfation failure mechanism on negative plates of lead-acid batteries and the pulse-repairing technology are analyzed, and an online automatic maintenance device based-on the Boost converter is designed. The device uses ATmega16 microcontroller as its controller. The test results show that by adjusting the hardware devices and programs the frequency and amplitude of charge-and-discharge pulses can be changed. And when the battery voltage is too low the device can generate sound and light alarm. The device meets the design requirements.

A novel electrochemical approach on the effect of alloying elements on self-discharge and discharge delivered current density of Pb–Ca–Ag lead-acid battery plates

The aim of this research is to examine the effect of alloying elements in positive plate composition of a lead-acid battery on its self-discharge and delivered current density in discharge state performances. To elucidate, a positive and negative lead-acid battery plates of two alloys namely Pb–Ca–Ag and Pb–Sb are investigated through electrochemical measurements in battery solution. Higher delivered current density of Pb–Ca–Ag cell in compare with Pb–Sb cell is observed for 25 days of 33 measurement days. The evolution of couple potential for both cases shows that the Pb–Ca–Ag cell potential achieves a value in the potential range of water stability after 25 days while in case of Pb–Sb cell, it remains well beyond the water stability potential domain for 33 days of measurements. Further investigations demonstrate that Pb–Sb cell current density is mainly caused by Pb oxidation reaction on negative plate while both anodic and cathodic polarizations (mixed polarization) are responsible in the case of Pb–Ca–Ag cell.

Influence of expander components on the processes at the negative plates of lead-acid cells on high-rate partial-state-of-charge cycling. Part II. Effect of carbon additives on the processes of charge and discharge of negative plates

Lead-acid batteries operated in the high-rate partial-state-of-charge (HRPSoC) duty rapidly lose capacity on cycling, because of sulfation of the negative plates. As the battery operates from a partially discharged state, the small PbSO 4 crystals dissolve and precipitate onto the bigger crystals. The latter have low solubility and hence PbSO 4 accumulates progressively in the negative plates causing capacity loss. In order to suppress this process, the rate of the charge process should be increased. In a previous publication of ours we have established that reduction of Pb 2+ ions to Pb may proceed on the surface of both Pb and carbon black particles. Hence, the reversibility of the charge–discharge processes improves, which leads to improved cycle life performance of the batteries in the HRPSoC mode. However, not all carbon forms accelerate the charge processes. The present paper discusses the electrochemical properties of two groups of carbon blacks: Printex and active carbons. The influence of Vaniseprse A and BaSO 4 (the other two components of the expander added to the negative plates) on the reversibility of the charge–discharge processes on the negative plates is also considered. It has been established that lignosulfonates are adsorbed onto the lead surface and retard charging of the battery. BaSO 4 has the opposite effect, which improves the reversibility of the processes on cycling and hence prolongs battery life in the HRPSoC duty. It has been established that the cycle life of lead-acid cells depends on the type of carbon black or active carbon added to the negative plates. When the carbon particles are of nano-sizes (<180 nm), the HRPSoC cycle life is between 10,000 and 20,000 cycles. Lignosulfonates suppress this beneficial effect of carbon black and activated carbon additives to about 10,000 cycles. Cells with active carbons have the longest cycle life when they contain also BaSO 4 but no lignosulfonate. A summary of the effects of the three expander components on the elementary processes during charge of negative lead-acid battery plates is presented at the end of the paper.

Optimization studies of carbon additives to negative active material for the purpose of extending the life of VRLA batteries in high-rate partial-state-of-charge operation

The negative plates of lead-acid batteries subjected to partial-state-of-charge (PSOC) operation fail because of the development of an electrically inert film of lead sulfate on their surfaces. It has been found that carbon additives to the negative active material can significantly increase their cycle life in this type of operation. In this paper we show that various types of carbon, including graphite, carbon black eliminate the surface development of lead sulfate and that, in their presence, the lead sulfate becomes homogeneously distributed throughout the active material. Examination of active material by energy dispersive spectroscopy after extensive cycling shows that lead formed during charge of lead sulfate preferentially deposits on the carbon particles that have been embedded in the active material. Electrochemical studies have been carried out on a number of types of carbon additives having a wide range of properties. These included flake, expanded and synthetic graphite, isotropically graphitized carbon, carbon black and activated carbon. We have investigated their effect on the resistivity and surface areas of the negative active material and also on such electrochemical properties as active material utilization and cycle life. Most of the carbon additives increase the utilization of the active material and impressive increases in cycle life have been obtained with over 6000 capacity turnovers having been achieved. However, at this time, we have not been able to correlate either the type or the properties of the carbon with capacity or cycle life. Further work is needed in this area. The increases that have been achieved in cycle life provide evidence that the lead-acid battery is a viable low cost option for hybrid-electric vehicle use.

Influence of expander components on the processes at the negative plates of lead-acid cells on high-rate partial-state-of-charge cycling. Part I: Effect of lignosulfonates and BaSO 4 on the processes of charge and discharge of negative plates

This study investigates the influence of the organic expander component (Vanisperse A) and of BaSO 4 on the performance of negative lead-acid battery plates on high-rate partial-state-of-charge (HRPSoC) cycling. Batteries operating in the HRPSoC mode should be classified as a separate type of lead-acid batteries. Hence, the additives to the negative plates should differ from the conventional expander composition. It has been established that lignosulfonates are adsorbed onto the lead surface and thus impede the charge processes, which results in impaired reversibility of the charge–discharge processes and hence shorter cycle life on HRPSoC operation, limited by sulfation of the negative plates. BaSO 4 exerts the opposite effect: it improves the reversibility of the processes in the HRPSoC mode and hence prolongs the cycle life of the cells. The most pronounced effect of BaSO 4 has been registered when it is added in concentration of 1.0 wt.% versus the leady oxide (LO) used for paste preparation. It has also been established that BaSO 4 lowers the overpotential of PbSO 4 nucleation. The results of the present investigation indicate that BaSO 4 affects also the crystallization process of Pb during cell charging. Thus, BaSO 4 eventually improves the performance characteristics of lead-acid cells on HRPSoC cycling.

Mechanism of action of electrochemically active carbons on the processes that take place at the negative plates of lead-acid batteries

It is known that negative plates of lead-acid batteries have low charge acceptance when cycled at high rates and progressively accumulate lead sulphate on high-rate partial-state-of-charge (HRPSoC) operation in hybrid-electric vehicle (HEV) applications. Addition of some carbon or graphite forms to the negative paste mix improves the charge efficiency and slows down sulfation of the negative plates. The present investigation aims to elucidate the contribution of electrochemically active carbon (EAC) additives to the mechanism of the electrochemical reactions of charge of the negative plates. Test cells are assembled with four types of EAC added to the negative paste mix in five different concentrations. Through analysis of the structure of NAM (including specific surface and pore radius measurements) and of the electrochemical parameters of the test cells on HRPSoC cycling, it is established that the electrochemical reaction of charge Pb 2+ + 2e − → Pb proceeds at 300–400 mV lower over-potentials on negative plates doped with EAC additives as compared to the charge potentials of cells with no carbon additives. Hence, electrochemically active carbons have a highly catalytic effect on the charge reaction and are directly involved in it. Consequently, the reversibility of the charge/discharge processes is improved, which eventually leads to longer battery cycle life. Thus, charging of the negative plates proceeds via a parallel mechanism on the surfaces of both Pb and EAC particles, at a higher rate on the EAC phase. Cells with EAC in NAM have the longest cycle life when their NAM specific surface is up to 4 m 2 g −1 against 0.5 m 2 g −1 for the lead surface. The proposed parallel mechanism of charge is verified experimentally on model Pb/EAC/PbSO 4 and Pb/EAC electrodes. During the charge and discharge cycles of the HRPSoC test, the EAC particles are involved in dynamic adsorption/desorption on the lead sulfate and lead surfaces. Another effect of electrochemically active carbons is also evidenced namely that, above a definite concentration, some EAC forms reduce the mean pore radius of NAM. When it diminishes to less than 1.5 μm, access of sulfuric acid into the pores is impeded and PbO forms instead of PbSO 4 in the pores of NAM during discharge. Thus, it may be presumed that electrochemically active carbons change the overall electrochemical reaction of charge and discharge of lead-acid cells when operated under HRPSoC cycling conditions.

Relationships between the Molecular Structure of Lignins and the Performance of the Negative Plates of Lead-Acid Batteries

Relationships between the Molecular Structure of Lignins and the Performance of the Negative Plates of Lead-Acid Batteries

Comparison of methods for adding expander to lead-acid battery plates—advantages and disadvantages

Expanders are an essential component of the negative plates of lead-acid batteries. They increase the surface area and stabilize the structure of the negative active material. They can be added to the negative paste mix in a number of ways and each of these has advantages and disadvantages. The individual components can be added to the paste mixer during paste preparation or they can be pre-mixed before addition. This pre-mixing can be done by the battery manufacturer or by companies that specialize in expander manufacture. This paper reviews the different ways in which expander can be added to negative paste mixes and discusses the consequences of each method. It concludes that the simplest, lowest cost and most risk-free option is to purchase pre-blended expander from a recognized supplier.

Influence of temperature on expander stability and on the cycle life of negative plates

The influence of temperature and the type of expander on the cycle life of negative lead–acid battery plates set to cycling tests following the requirements of the ECE-15 test protocol has been investigated. The plates prepared with the currently used expanders Vanisperse (Vs) or Indulin (In) alone have a considerably shorter cycle life than negative plates produced with a blend of the two expanders. The new experimental products UP-393 and UP-414 of Borregaard LignoTech (Norway) ensure much better cycle life performance when used for EV battery applications. Investigations on the influence of temperature on battery cycle life have evidenced that with increase of temperature the cycle life of the battery features a maximum at 40 °C (UP-393, Indulin+Vanisperse). At 60 °C almost all expanders disintegrate and the cycle life of the batteries decreases, though the plates with UP-393 and UP-414 have better cycle life performance than those with other expanders. A gradual degradation of the NAM structure is observed with batteries set to EV cycling. The energetic structure of NAM, which is built up of small crystals with large surface area, is converted into skeleton structure at the end of battery life, which comprises large crystals with small surface area yielding low battery capacity. On cycling at temperature about 60 °C, the NAM is converted into a well-developed network of thin lead branches with large pores in between. On discharge, some of these branches are oxidized more quickly, thus, excluding part of NAM from the current generation process, which consequently reduces the capacity of the negative plates.

Influence of phenolic group content in lignin expanders on the performance of negative lead–acid battery plates

Negative plates for lead–acid batteries containing lignin expander UP-414 with various phenolic group contents have been investigated. The members of the family of lignins UP-414 are produced by Borregaard LignoTech, Norway and differ mainly by the amount of phenolic groups and less so by the carboxylic groups in their structure, the content of all other functional groups (methoxyl, ketonic, etc.) being the same for all UP-414 products. The influence of phenolic group content in the expander on the performance of SLI batteries has been studied. It has been established that the batteries with PbSb grids exhibit a decline in C 20 capacity, CCA performance and cycle life, when the content of phenolic groups in the expander increases. The capacity, cycle life and self-discharge of batteries with PbSnCa grids do not depend on the content of phenolic groups in the lignin. It has been proved experimentally that lignin reacts with the ions of the grid alloying additives forming metal–lignin compounds, which exert an influence on the performance of the negative plates.

Effect of some elements on oxygen reduction and hydrogen evolution at lead-acid battery negative plates

The effects which the impurities As, Bi, Cd, Co, Cr, Ni, Sb, Se, Sn and Te have on the processes of hydrogen evolution and oxygen reduction on the negative plates of lead-acid batteries have been tested. This was done by measuring the gas pressure in sealed vessels containing cycled, wet, negative plates. The addition of As, Co, Ni, Sb and Te to the electrolyte used during the cycling increases the hydrogen ion discharge rate, whereas Cr, Bi and Sn have the opposite effect. In the case of oxygen, As, Bi, Ni, Sb, Se, Sn, and Te promote its reduction while Co and Cr suppress it. The effect of impurity concentration has also been considered.

In situ conductance measurements of lead accumulator negative plates

The electrical conductance of negative lead-acid battery plates was measured in situ by the d.c. method. By subtracting the conductance of the grid, the conductance of the active mass was obtained. With freshly charged plates this was appreciably lower and increased with time; this effect was attributed to adsorption of hydrogen on lead. During cycling, a decrease in the conductance was observed which is discussed in terms of recrystallization of the active mass. The conductance of dry plates was found to be appreciably lower than that of wet plates.

The impedance of a lead acid battery negative plate

An attempt is made to interpret the impedance, measured near to E°, of various negative lead acid battery plates in H 2SO 4.