Lead Acid Battery. Attacking Sulphate Passivation and Cyclability Problems

Table of Contents

INTRODUCTION

1.1 Timeline of Battery History:

1.2. Characteristics of Some batteries and achievable performance:

1.3. Lead-acid battery

1.3.1. Advantages of lead-acid system

1.3.2. Technical developments in Lead-acid battery:

1.3.3. Charging and Discharging Reactions:

1.3.4. Theoretical voltage and capacity:

1.3.5. Capacity of a cell:

1.3.6. Thickness of the plates and capacity:

1.3.7. Rate of Discharge

1.3.8. Electrolyte Temperature

1.3.9. Effect of Concentration of the electrolyte:

1.3.10. Manufacture of Lead-acid battery

1.3.11. Flow chart for the Manufacture of flooded lead-acid battery

1.4. Classification of Lead-acid battery:

1.4.1. SLI batteries:

1.4.2. Stationary batteries:

1.4.3. Motive power batteries:

1.4.4. Special purpose batteries:

1.4.5. Valve Regulated Lead-acid Batteries (VRLA)

1.5. Failures in Lead-acid batteries:

1.5.1. Sulphation is due to the following reasons:

1.5.2. Shedding of the positive mass:

1.5.3. Destruction of the positive grids:

1.5.4. Defects in the negative mass:

1.6. CHARGING OF LEAD-ACID BATTERY

1.6.1. Constant-current charging (CC)

1.6.2. Constant-Voltage charging (CV)

1.6.3. Taper charging

1.6.4. Pulse charging

1.6.5. Trickle Charging

1.6.6. Float Charging

1.6.7. Battery charger should have the following Characteristics

1.7. GRID MATERIALS:

1.7.1. Grid alloy properties

1.7.2. Ease of fabrication

1.7.3. Mechanical strength

1.7.4. Creep strength

1.7.5. Corrosion resistance

1.7.6. Conductivity

1.7.7. Compatibility with active material

1.7.8. High hydrogen and oxygen over potential

1.7.9. cost effective

1.7.10. Various Types OF Grid alloys:

1.7.11. Beneficial elements

1.7.12. Self discharge behaviour

1.7.13. Detrimental elements

1.8. GRID production methods:

1.9. VARIOUS TYPES OF GRIDS:

1. M C B-GRID

2. BOX –NEGATIVE PLATE

3. MONCHESTER GRID

4. IRONCLAD GRID

6. EXPERIMENTAL BATTERY GRID

LITERATURE SURVEY AND SCOPE OF THE WORK

2.1 LITERATURE SURVEY:

2.2. SCOPE OF THE WORK

EXPERIMENTAL DETAILS

3.1. Chemicals and materials used

3.2. Weight loss Studies

3.3. Cyclic Voltammetry

3.4. Impedance measurements

3.5. Anodic polarisation studies

3.6. CHRONO AMPEROMETRIC STUDIES

3.7. XRD

3.8. Scanning Electron Microscope

3.9. Charge acceptance studies.

3.10. cycle life test.

1. cycle life test with low capacity battery

2. Heavy load endorsement test

RESULTS & DISCUSSION

4.1. WEIGHT LOSS STUDIES

4.1.1. Dense Lead sulphate removal from the positive plate.

4.1.2. Dense lead sulphate removal from the negative plate

4.2. Cyclic Voltammeteric Studies

4.2.1 .Cyclic Voltammetric Studies of the Positive Plate.

CV STUDIES in electrolyte containing different acetates.

CV STUDIES for the mixture of boric acid and ACETATES.

CV STUDIES for the mixture of Phosphoric acid and ACETATES.

Electrochemical Kinetic Parameters for the formation of lead sulphate in the absence and presence of sodium acetate and Phosphoric acid combined additive.

4.2.2. Cyclic VOLTAMMETRIC STUDIES of the negative PLATE.

CV STUDIES IN ELECTROLYTE CONTAINING DIFFERENT ACETATES.

CV STUDIES FOR THE MIXTURE OF BORIC ACID AND ACETATES.

CV STUDIES FOR THE MIXTURE OF PHOSPHORIC ACID AND ACETATES.

ELECTROCHEMICAL KINETIC PARAMETERS FOR THE FORMATION OF LEAD SULPHATE IN THE ABSENCE AND PRESENCE OF SODIUM ACETATE AND PHOSPHORIC ACID COMBINED ADDITIVE.

4.3. ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY STUDIES

4.3.1. EIS STUDIES on active / passivated POSITIVE PLATES in the absence and presence of additives.

4.3.2. EIS STUDIES on active / passivated NEGATIVE PLATES in the absence and presence of additives.

4.4. Studies on the passivation phenomena of lead (negative electrode) in the BATTERY ELECTROLYTE.

4.5. Self-Corrosion of the electrodes in the battery electrolytes

4.6. Studies on the electro formation of Lead Sulphate with and with out the additives.

4.7. SEM STUDIES.

4.8. X-ray diffraction studies.

4.9 CHARGE ACCEPTANCE STUDIES.

4.1 CYCLE LIFE TEST

4.10.1. Slow rate cycle life test with low capacity Battery.

4.10.2. HEAVY LOAD ENDORSEMENT TEST WITH HEAVY DUTY BATTERY

CONCLUSIONS

Research Objectives and Themes

The research investigates the passivation of lead-acid batteries, a phenomenon leading to premature capacity loss in both positive and negative electrodes. The work aims to identify effective electrolyte additives, specifically acetates, boric acid, and phosphoric acid, to dissolve lead sulphate deposits, improve electrode reversibility, and enhance overall cyclability without compromising battery performance.

• Examination of lead sulphate passivation mechanisms in lead-acid battery electrodes.
• Evaluation of various acetates and their synergistic effects with boric and phosphoric acid on electrode activity.
• Application of weight loss studies and electrochemical techniques (Cyclic Voltammetry, Impedance Spectroscopy) to analyze performance.
• Monitoring of capacity recovery and charge acceptance in passivated batteries through long-term cycling tests.

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Summary of Chapters

INTRODUCTION: This chapter covers the historical development of battery technology and the fundamental principles, classification, and failure mechanisms of lead-acid battery systems.

LITERATURE SURVEY AND SCOPE OF THE WORK: This chapter reviews previous research on lead passivation and details the research objective to investigate the synergistic effects of acetate, boric acid, and phosphoric acid additives on performance.

EXPERIMENTAL DETAILS: This chapter describes the analytical techniques utilized, including weight loss, cyclic voltammetry, impedance spectroscopy, SEM, and XRD, to evaluate the electrodes.

RESULTS & DISCUSSION: This chapter analyzes the experimental data from weight loss, cyclic voltammetry, and impedance studies to evaluate the influence of specific additives on lead sulphate removal and electrode activity.

CONCLUSIONS: This chapter summarizes the findings, confirming that a combination of sodium acetate and phosphoric acid is the most effective additive formulation for mitigating lead sulphate passivation and improving battery cyclability.

Keywords

Lead-acid battery, Sulphation, Passivation, Sodium acetate, Phosphoric acid, Boric acid, Cyclic Voltammetry, Electrochemical Impedance Spectroscopy, Charge acceptance, Electrode kinetics, Cycle life, Grid corrosion, Lead sulphate, Reversibility, Battery additives

Frequently Asked Questions

What is the fundamental focus of this research?

The research focuses on addressing the problem of sulphation, or passivation, in lead-acid battery electrodes, which limits battery capacity and life, by testing various electrolyte additives.

What are the central thematic fields?

The central fields include electrochemistry, lead-acid battery technology, surface characterization of electrode active materials, and electrolyte additive optimization.

What is the primary goal of the study?

The primary goal is to find an effective combination of additives (specifically acetates, boric acid, and phosphoric acid) that can prevent the formation of hard lead sulphate or facilitate its removal, thereby extending the cyclability and performance of lead-acid batteries.

Which scientific methods are employed?

The research employs a variety of techniques: weight loss studies for dissolution analysis, Cyclic Voltammetry for studying reversibility, Electrochemical Impedance Spectroscopy (EIS) for kinetic studies, and surface analysis via SEM and XRD.

What topics are covered in the main body?

The main body examines the historical background of batteries, the theory of lead-acid battery operation and failure (passivation), experimental procedures for evaluation, and a comprehensive discussion of results regarding the efficacy of different additive mixtures on positive and negative plates.

Which keywords define this work?

Key terms include Lead-acid battery, Sulphation, Passivation, Sodium acetate, Phosphoric acid, Boric acid, Cyclic Voltammetry, and Electrode kinetics.

What is the significance of the "Weight Loss Study" mentioned?

This study helps determine the optimal concentration of additives required to preferentially dissolve hard lead sulphate deposits from the pores of passivated electrodes, ensuring the active sites become available again.

What did the results reveal about the sodium acetate and phosphoric acid combination?

The study concludes that the combined addition of sodium acetate and phosphoric acid is highly effective, showing synergy in preventing capacity loss and maintaining battery performance during heavy-duty cycling compared to using additives individually.