Ramasamy Kulandaivel Saminathan
Transcript of Ramasamy Kulandaivel Saminathan
Ramasamy Kulandaivel Saminathan
Lead Acid Battery.Attacking SulphatePassivation and Cyclability Problems
Research Paper(postgraduate)
Natural Science
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Ramasamy Kulandaivel Saminathan
Lead Acid Battery. Attacking Sulphate Passivation andCyclability Problems
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LEAD ACID BATTERY – ATTACKING SULPHATE PASSIVATION AND
CYCLABILITY PROBLEMS
RAMASAMY K. SAMINATHAN
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TABLE OF CONTENTS
INTRODUCTION ........................................................................................ 9
1.1 Timeline of Battery History: ..............................................................13
1.2. Characteristics of Some batteries and achievable performance: .....15
1.3. Lead-acid battery ..............................................................................16
1.3.1. Advantages of lead-acid system ....................................................16
1.3.2. Technical developments in Lead-acid battery: ..............................17
1.3.3. Charging and Discharging Reactions: ............................................19
1.3.4. Theoretical voltage and capacity: ..................................................20
1.3.5. Capacity of a cell: ...........................................................................20
1.3.6. Thickness of the plates and capacity: ............................................23
1.3.7. Rate of Discharge ...........................................................................24
1.3.8. Electrolyte Temperature ...............................................................25
1.3.9. Effect of Concentration of the electrolyte: ....................................25
1.3.10. Manufacture of Lead-acid battery ...............................................26
1.3.11. Flow chart for the Manufacture of flooded lead-acid battery ....27 1.4. Classification of Lead-acid battery: ......................................................................... 28
1.4.1. SLI batteries: ..................................................................................28
1.4.2. Stationary batteries: ......................................................................28
1.4.3. Motive power batteries:................................................................28
1.4.4. Special purpose batteries: .............................................................28
1.4.5. Valve Regulated Lead-acid Batteries (VRLA) .................................29
1.5. Failures in Lead-acid batteries: .........................................................29
1.5.1. Sulphation is due to the following reasons: ..................................29
1.5.2. Shedding of the positive mass: ......................................................30
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1.5.3. Destruction of the positive grids: ..................................................30
1.5.4. Defects in the negative mass: ........................................................31 1.6. CHARGING OF LEAD-ACID BATTERY ........................................................................ 32
1.6.1. Constant-current charging (CC) .....................................................32
1.6.2. Constant-Voltage charging (CV).....................................................33
1.6.3. Taper charging ...............................................................................33
1.6.4. Pulse charging ................................................................................33
1.6.5. Trickle Charging .............................................................................33
1.6.6. Float Charging ................................................................................34
1.6.7. Battery charger should have the following Characteristics ...........34 1.7. GRID MATERIALS: .................................................................................................... 34
1.7.1. Grid alloy properties ......................................................................34
1.7.2. Ease of fabrication .........................................................................35
1.7.3. Mechanical strength ......................................................................35
1.7.4. Creep strength ...............................................................................35
1.7.5. Corrosion resistance ......................................................................36
1.7.6. Conductivity ...................................................................................36
1.7.7. Compatibility with active material ................................................36
1.7.8. High hydrogen and oxygen over potential ....................................37
1.7.9. cost effective .................................................................................37
1.7.10. Various Types OF Grid alloys: ......................................................37
1.7.11. Beneficial elements .....................................................................37
1.7.12. Self discharge behaviour .............................................................39
1.7.13. Detrimental elements..................................................................39 1.8. GRID production methods: ...................................................................................... 39
1.9. VARIOUS TYPES OF GRIDS: ..................................................................................... 41
1. M C B-GRID ................................................................................................................. 41
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2. BOX –NEGATIVE PLATE ............................................................................................... 41
3. MONCHESTER GRID .................................................................................................... 41
4. IRONCLAD GRID .......................................................................................................... 41
6. EXPERIMENTAL BATTERY GRID .................................................................................. 41
References ...................................................................................................................... 42
LITERATURE SURVEY AND SCOPE OF THE WORK ........................................................... 46
2.1 LITERATURE SURVEY: .........................................................................46 REFERENCES ................................................................................................................... 64
2.2. SCOPE OF THE WORK............................................................................................... 67
EXPERIMENTAL DETAILS................................................................................................. 70
3.1. Chemicals and materials used ..........................................................70
3.2. Weight loss Studies ..........................................................................71
3.3. Cyclic Voltammetry ..........................................................................72
3.4. Impedance measurements ...............................................................75
3.5. Anodic polarisation studies ..............................................................76
3.6. CHRONO AMPEROMETRIC STUDIES .................................................76
3.7. XRD ...................................................................................................77
3.8. Scanning Electron Microscope..........................................................77
3.9. Charge acceptance studies. ..............................................................78
3.10. cycle life test. ..................................................................................78
1. cycle life test with low capacity battery ..............................................78
2. Heavy load endorsement test .............................................................79 REFERENCES : ................................................................................................................. 80
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RESULTS & DISCUSSION.................................................................................................. 81
4.1. WEIGHT LOSS STUDIES .....................................................................82
4.1.1. Dense Lead sulphate removal from the positive plate. ................82
4.1.2. Dense lead sulphate removal from the negative plate .................87 SUMMARY:..................................................................................................................... 88
4.2. Cyclic Voltammeteric Studies ........................................................92
4.2.1 .Cyclic Voltammetric Studies of the Positive Plate. ........................92
CV STUDIES in electrolyte containing different acetates. .......................96 CV STUDIES for the mixture of boric acid and ACETATES.............................................. 112
CV STUDIES for the mixture of Phosphoric acid and ACETATES. ...........128
Electrochemical Kinetic Parameters for the formation of lead sulphate in the absence and presence of sodium acetate and Phosphoric acid
combined additive. ................................................................................145
4.2.2. Cyclic VOLTAMMETRIC STUDIES of the negative PLATE. .............148
CV STUDIES IN ELECTROLYTE CONTAINING DIFFERENT ACETATES. ......151
CV STUDIES FOR THE MIXTURE OF BORIC ACID AND ACETATES. ..........165
CV STUDIES FOR THE MIXTURE OF PHOSPHORIC ACID AND ACETATES. ...............................................................................................................181
ELECTROCHEMICAL KINETIC PARAMETERS FOR THE FORMATION OF LEAD SULPHATE IN THE ABSENCE AND PRESENCE OF SODIUM ACETATE
AND PHOSPHORIC ACID COMBINED ADDITIVE. ....................................197 SUMMARY:................................................................................................................... 198
4.3. ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY STUDIES ..........202
4.3.1. EIS STUDIES on active / passivated POSITIVE PLATES in the absence and presence of additives. ......................................................202
4.3.2. EIS STUDIES on active / passivated NEGATIVE PLATES in the absence and presence of additives. ......................................................212
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4.4. Studies on the passivation phenomena of lead (negative electrode) in the BATTERY ELECTROLYTE. ..............................................................221
4.5. Self-Corrosion of the electrodes in the battery electrolytes ..........225
4.6. Studies on the electro formation of Lead Sulphate with and with out the additives. .........................................................................................228
4.7. SEM STUDIES. .................................................................................236
4.8. X-ray diffraction studies. ................................................................243 4.9 CHARGE ACCEPTANCE STUDIES. ............................................................................. 246
4.1 CYCLE LIFE TEST ...................................................................................................... 248
4.10.1. Slow rate cycle life test with low capacity Battery. ...................248 4.10.2. HEAVY LOAD ENDORSEMENT TEST WITH HEAVY DUTY BATTERY .................... 251
REFERENCES: ................................................................................................................ 253 CONCLUSIONS .............................................................................................................. 257
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CHAPTER-1
INTRODUCTION
A battery is defined as an electrical storage device, which is
able to convert the stored chemical energy into work of an electrical
nature. The word battery was originally applied by Benjamin Franklin
as a collective term to describe the apparatus obtained when several
leyden jar capacitors were connected together. When the batteries
were first invented, they had seen as merely laboratory curiosities.
Faraday distinguished electrodes into anode and cathode. These
were derived from the Greek words ‘way up’ and ‘going down’
respectively as Faraday supposed that the anode releases the
electrons which are consumed by the cathode.
It was just 200 years since the invention of the first battery; this
has been ascribed to Alessandro Volta (1745-1827), Professor of
Natural Philosophy (physics) at Pavia University, Italy. His name is
commemorated at all time by the unit of electrical potential, the volt.
Volta’s famous experiment, described in a letter to the Royal Society
of London in 1800, involved the assembly of a pile of alternate silver
(or brass or copper) and zinc (or tin) discs, with each pair of dissimilar
metals separated from the next by a piece of cloth which was
saturated with brine. One end of the pile was terminated in a silver
disc and the other in a zinc disc, and a continuous current of electricity
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was produced as soon as a wire conductor connected the two. This
was the first galvanic or primary battery and became known as
‘Volta’s pile’. Batteries have come a long way in 200 years!
The next significant step in the development of batteries was the
invention of the ‘Daniell cell’ by John Daniell (1790 -1845), Professor
of Chemistry at King’s College, London. In 1836, he took a copper
vessel filled with copper sulfate solution and Zinc rod with zinc
sulphate solution separated by gullet of an ox. This constituted a so
called ‘cell’. Discharge of the cell caused the zinc electrode to dissolve
and copper to be deposited at the positive electrode. The cell
produced a voltage of 1.1 V.
This was possibly the first practical galvanic cell to give a
continuous current of useful magnitude. Further modifications (Fig1.1a)
included the use of porous ceramic pots (‘separators’) instead of
animal membranes, substitution of sulfuric acid by zinc or magnesium
sulfate, and the development of multi-cell batteries. Daniell cells were
adopted by commercial telegraphic systems following a rapid
expansion of such services in the early 1850s.
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A subsequent major advance was made by the French chemist
Georges Leclanche´ (1839-1882) who, in 1866, invented the primary
cell, which bears his name. This cell consists of a zinc rod as the
negative electrode and a carbon rod as the positive electrode, both
immersed in a solution of ammonium chloride contained in a glass jar.
The positive electrode was housed in an inner porous
ceramic pot and packed around with a mixture of powdered
manganese dioxide and carbon. The cell, which has been extensively
developed ever since, gives a voltage of 1.5 V. A major advance took
place in the 19th century when the idea of using a zinc cane as both
container and electrode was patented and came into general use.
Before the invention of these galvanic cells, the only electricity known
Fig 1.1. a) Schematic of Plante`s lead acid cell b) early illustration of a battery of three Plante`s lead acid cell [1]
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and available was static electricity, as produced by friction between
dissimilar materials or in thunderstorms.
The first effective demonstration of a secondary (rechargeable)
cell was given in 1859 by the French chemist Gaston Plante´ (1834-
1889). This cell consisted of two concentric spirals of lead sheet,
separated by porous cloth, immersed in dilute sulphuric acid within a
cylindrical glass vessel .The ‘lead-acid battery’ thus constructed gave
an output of 2 V, but very little current was initially gained because of
the low surface area of the plates. By a series of discharges and
charges, the chemical reactions at the surface of the plates resulted in
the gradual build-up of deposits of higher surface area and the current
was progressively improved. This became known as the ‘formation
process’, a term still used today in the initial charging of lead-acid
batteries. In March 1860, Plante´ presented a battery of ten cells (20
V) to the French Academy of Sciences in Paris; an illustration of an
early battery of Plante´ cells is shown in Figure 1.1b.
An important advancement in the technology of the Lead-Acid
battery was achieved by the French chemical engineer Camille Faure´
(1840-1898) who, in 1881, showed the change in level of electrical
charge, or the ‘capacity’, of the system could be greatly increased by
coating the lead plates with a paste of lead dioxide and sulphuric acid.
This process also reduced the time required for plate formation from
months to hours, and thus became part of the basic technology of the
lead-acid battery industry.
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an array of charged glass plates.
1791 Luigi Galvani Experiment
1800 Alessandro Volta invented the voltaic pile and discovered the
first practical method of generating electricity.
1836 John F. Daniel invented the Daniel Cell that used two
electrolytes
1839 William Robert Grove developed the first fuel cell.
1860 Gaston Plante developed the first practical storage lead-acid
battery.
The most important event in the history of Lead-acid battery was the invention of the electric self-starter by kettering in 1912. As a result, the battery market has grown with the growth of the automobile market throughout the last century.
1.1. Timeline of Battery History: 1748 Benjamin Franklin first coined the term "battery" to describe
Fig 1.2. a) Schematic of Plante`s lead acid cell b) early illustration of a battery of nine Plante`s lead acid cell [1]
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1866 Georges Leclanche patented the carbon-zinc wet cell
battery.
1868 Twenty thousand of Georges Leclanche's cells were used
with telegraph
1881 J.A. Thiebaut patented the first battery with both the negative
electrode and porous pot placed in a zinc cup.
1881 Carl Gassner invented the first commercially successful dry
cell battery
1899 Waldmar Jungner invented the first nickel-cadmium
rechargeable battery.
1903 Thomas Alva Edison invented the alkaline storage battery.
1927 Andre, Zinc-Silver oxide cells
1928 Pflerder, spoon, Gimelin,& Ackerman Sintered electrode
1935 Haring & Thomas, Lead-calcium alloy
1949 Lew Urry invented the small alkaline battery.
1950 Ruben, sealed Zinc- Mercuric oxide cell
1954 Gerald Pearson, Calvin Fuller and Daryl Chapin - first solar
battery.
1956 Bacon, alkaline fuel cell
1966 Kummer & Weber Sodium-Sulphur battery
1970 Tobias aprotic solvent research
1980 Sealed lead-acid batteries become common
To
present
VARLA, Li-Ion Batteries successfully commercialised
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A number of primary, secondary, reserve and fuel cells are also
developed. Each one has special features and they have their own
limitations. Performance and characteristic of few systems are
presented in the following table.
1.2. Characteristics of Some batteries and achievable performance:
Lead -
Acid
Ni-
Cd Zn-air Ni-Fe Ni-Zn Zn-Cl2 Na-S Li-TiS2 Li-S
Electrolyte H2SO4 KOH KOH KOH KOH ZnCl2 Al2O3 Various Licl /
LiKI
OCV (Volt per
cell) 2.05 1.35 1.65 1.37 1.71 2.12 2.1-1.8 2.3
1.9-
1.4
Life cycles
(80%) DOD 500 2000 1000 2000 350 250 2000 250 200
Energy
Efficiency (%) 75 70 55 60 75 65 75 --- 75
Specific Energy
(Wh Kg-1) (1h
rate)
24 28 80 40 70 120 120 --- 140
Wh Kg-1 5h rate 40 30 100 55 75 150 140 100 ---
Energy density
(Wh dm-3) (1h
rate)
70 60 80 100 140 180 170 330 ---
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1.3. Lead-acid battery
Lead - acid battery is the workhorse of the rechargeable battery
systems. It is the single most used battery worldwide. Although many
new systems may challenge its position, its reliability, low cost and
good operational life, can’t so easily be substituted. The first secondary battery (Lead-acid battery) was discovered and
developed by Gaston plants [1-5] in 1859. Since then enormous developments
have been taken place in the science and technology of the battery system. A
number of references are available dealing with Lead-acid battery [6-20]. In
principle, the Lead-acid battery consists of two electrodes immersed in a common
electrolyte. The characteristic feature of such a cell is the conversion of electron
conduction into ionic conduction at the phase boundary of the
electrode/electrolyte. This change in conductivity is established by the
electrochemical reaction, i.e., a chemical reaction accompanied with the
exchange of electric charge.
1.3.1. Advantages of lead-acid system Lead-acid battery is technically well-established electrochemical device
and is produced in quantities for different applications. Its production and use
continues to grow. The most attractiveness of the Lead-acid battery is due to the
following reasons.
Well established technology of production.
• Popular low-cost secondary battery.
• Capable of manufacturing with simple methods.
• Manufactured in capacity ranges from smaller than 1 Ah to 1000 Ah.
• Good high-rate performance-suitable for engine starting.
• Good low and high temperature performance
• Easy state-of-charge indication.
• Electrically efficient .
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1.3.2. Technical developments in Lead-acid battery: Year Precursor Achievements
1860 Raymond Gaston
Plante
First practical Lead-acid battery corroded Pb foil to form
active material.
1881 Faure Coated lead foils with PbO2 – H2SO4 paste for positive
electrode to increase capacity.
1881 Sellon Pb – Sb grid alloy.
1881 Volkinar Perforated lead plates to provide pockets for support of
oxide.
1882 Brush Mechanically bonded PbO2 to lead plates.
1882 Gladstone and
Tribe
Double sulphate theory of reaction in Lead-acid battery.
PbO3 + Pb + 2H2SO4 2PbSO4 + 2H2O
1883 Tudor Pasted mixture of lead oxides on a grid
1886 Lucas Formed Lead plates in solutions of chlorates and per
chlorates.
1890 Phillipart Early tubular construction individual rings.
1890 Woodward Early tubular construction.
1935 Haring and
Thomas
Pb – Ca alloy grids.
1935 Harmer and
Harned
Experimental proof of double sulphate theory.
1956 Bode and Voss
Ruetschi and
Cahan J.Burbank
Classification of properties of two crystalline forms of
PbO2.
1990 To present Expanded metal grid technology composite plastic / metal
grids sealed and maintenance – free LAB. Glass fiber and
improved seperators high energy density batteries.
VRLA with AGM Seperators
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The electrochemical reactions specify the most important parameters of the
cell. The cell voltage is determined by chemical affinity of the reacting substances
and capacity is defined by the amount of electrode material that can be converted.
The reactions taking place in the Lead-acid battery are given below.
Positive Electrode:
PbO2 + 3H+ + HSO4- + 2e - PbSO4 + 2H2O -- (1)
E0 = + 1.690 V
Negative Electrode:
Pb + HSO4- PbSO4 + H+ + 2e- -- (2)
E0 = - 0.350V
Overall reaction:
Pb + PbO2 + 2HSO4- + 2H+ 2PbSO4 + 2H2O -- (3)
E0 = + 2.04V
Equation (1) and (2) represents reactions during discharge, where lead dioxide is
reduced to lead sulphate at the positive electrode, while metallic lead is oxidized
at the negative electrode. Reversal of the current reverses (1) and (2), and
recharges the cell.
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1.3.3. Charging and Discharging Reactions:
NEGATIVE PLATE ELECTROLYTE
POSITIVE PLATE
DISCHARGE REACTIONS
ORIGINAL ACTIVE MATERIAL
Pb
2H2SO4 , 2H20
PbO2
IONISATION PROCESS
SO4 2- , SO4
2-, 4H+
4OH- , Pb 4+
CURRENT –PRODUCING PROCESS
2 e - + Pb 2+
Pb 2+ - 2e-
FINAL PRODUCTS OF DISCHARGE
PbSO4
4H2O
2H20 2H2O
PbSO4
CHARGE REACTIONS
FINAL PRODUCTS OF DISCHARGE
PbSO4
4H2O
PbSO4
IONISATION PROCESS
Pb2+, SO42-
2H+, 4 OH- , 2H+
S042-, Pb2+
CURRENT – CONSUMBTION PROCESS
2e-
2e- Pb 4+
ORIGINAL ACTIVE MATERIAL
Pb
2H20
H2SO4 H2SO4
PbO2
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1.3.4. Theoretical voltage and capacity: To calculate the equilibrium cell voltage, the change in free energy (ΔG) is
used, which is derived as the difference of the standard free energies of the
substance involved in the reaction. For equation (3) this difference turns out to be
ΔG = -372.5 KJ mole-1
and the standard equilibrium cell voltage (emf) is
E0 = 372.5 *1000 / 2*96500 = 1.930V
Since, free energy depends upon concentration of electrolyte, the equilibrium cell
voltage changes with the concentration or activity of the reacting species except
those present in solid state (activity = 1) according to the Nernst equation,
E = E0 + RT/ nF ln aH + aHSO4-
aH2O
where E0 represents the standard equilibrium cell voltage, ‘a’ the activity (moles/
litre). The Lead-acid cell can be represented as follows.
(-) Pb / PbSO4 / H2SO4 / PbO2 / PbSO4 (+)
The electric potential difference is equal in sign and magnitude to the electrode
potential of a metallic conductor attached to the right hand side electrode minus
that of an identical lead on the left.
Ecell = Eright - Eleft
= 1690 – (-350) mV
= 2040 mV
1.3.5. Capacity of a cell: Specific capacity (k) is defined as the ampere hours obtainable from a unit
of the active material e.g. Ahkg-1. A related parameter is the coefficient of
utilization of active material .
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The current density is expressed as
c.d (Adm-2 or Am-2).
The area expressed may be either the apparent geometric area (reckoned
for the two sides of the plates) or the BET surface area, sometimes the c.d. is
expressed as amperes per Kg of the active materials.
The capacity (C) is usually expressed in Ah (3.6 x 103 Coulombs)
specifying the flow of current per unit area in number of hours eg. C20 = 60 Ah
implies that the battery can be discharged at 3 amperes over a period of 20 hours
and it can deliver the declared capacity of 60 Ah before it reaches its end voltage
(also called cut off voltage) usually about 1.75 to 1.70 V per cell. Sometimes the
batteries are tested for their output in terms of unit power, energy for a unit time,
watts.
In the electrochemical power source, the full utilization of the active
material has not been realized. Thus in declaring the capacity, two types are
distinguished, namely the theoretical capacity CTh and the practical capacity (C).
The practical capacity depends on several parameters like discharge rate, Cell
design, etc., and hence has to be declared very specifically under a given set of
conditions.
The theoretical capacity is determined from the reaction according to
Faraday’s laws and is equivalent to ZF Coulombs for one mole of reactants (here
PbO2, Pb and H2SO4). The effective capacity equal to Current x Time is
determined by discharging the battery at a definite rate over a period of time till it
reaches the cut – off voltage.
From equation (3) it can be readily estimated that the theoretical amounts of the
reacting materials required for 1 Ah are
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207.2 + 239.2 + 196g = 642.4g
For 2 x 96500 C or 2 x 26.80 Ah = 53.6 Ah.
239.2 The weight of PbO2 for 1Ah is equal to =
53.6 = 4.46 g.
Similarly the weight of PbSO4 1 Ah is = 5.65 g
(Formed during discharge and consumed during charge )
Likewise the weight of Pb and H2SO4 required per Ah will be 3.86 and
3.66g respectively. Assuming the discharge voltage to be 2.0V, Specific energy
per unit weight will be
= 53.60 x 2.0 / 0.6424
= 167 Wh / Kg
The value is only by the weight of the reacting substances. The inclusion of
the weight of the inactive components such as grids, containers, and covers,
poles and separators reduces the practical energy density to values as low as 30-
40 WhKg-1 (at 5- hour rate of discharge). Since the reaction product on both
plates is PbSO4, which is a poor conductor of electricity, the realization of the
theoretical energy density is made still more difficult.
Capacity of the battery depends on various factors such as the amount of
active material, porosity of the plate, thickness of the plate, rate of discharge,
electrolyte temperature and concentration of the electrolyte.
The theoretical requirements per Ah of capacity of the active materials are
given below