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VRLA BatteryBasic Information
Boowen Lee
Battery Product Marketing Section
Emerson Network Power Co.,Ltd.
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PartI: Concept of Battery
Part II: VRLA Battery Sealing Mechanism
Part III: VRLA Battery Construction
Part IV: VRLA Battery Charge and
Discharge Characteristic
VRLA Battery Basic Information
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Battery Cell
Cell
An assembly of electrodes andelectrolyte which constitutes thebasic unit of a battery
Battery
Electrochemical power source
Receives, stores, and deliverselectrical energy
Includes one or more cells
StringSeries connection of batteries
Two dissimilar metals +electrolyte
v
=1cell
Positive plate
With higherpositive voltage
Electrical Chemical
Energy Energy
e-
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Positive platelead dioxidePbO2
Negative plateleadPb
electrolytesulfuricH2SO4solution
12v
-+ -+
12v=24vseries connection:
voltage =Vb1+Vb2+nV
Lead-Acid Battery
Form 2V cell
Negative plate Positive plate
6 cells=12V battery
C
+- -+
C=2C
parallel connection:
Capacity=Cb1+Cb2+=nC
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Lead-Acid Batterytwo general type
Flooded Batteryor wet type or open vented type
VRLA BatteryValve Regulated Lead-Acid Battery
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Flooded Battery
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Flooded Batteryused with DC Power
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VRLA Battery
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VRLA Batteryused with UPS
UPS Battery
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VRLA Batteryused with DC Power
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Earlier technology
Need separate battery room
Two type battery comparison
VRLA type
VRLA battery has substitute the flooded battery in many fields
Need maintenance periodically
Flooded type
Need additional safety measure
Keep vertical stand state
Need excess connection cable
Oxygen recombination technology
May apply near the equipment
No water replenish needed
Acid filtrate and anti-explosion prevention
May install horizontally
May use inside the load
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Two VRLA Battery type
AGM type
high energy ratioaccording to
volume or weight
support fast charge
adapt to low temperatureenvironment
middle degree discharge is
recommendedsensitive to high temperature
GEL type
adapt to deep cycle discharge
may applied to high temperature
environment
fit in with little current dischargemode
no oxygen recombination
reaction occur at initial periodrandom gas channel
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Part I: Concept of Battery
PartII: VRLA Battery Sealing Mechanism
Part III: VRLA Battery ConstructionPart IV: VRLA Battery Charge and
Discharge Characteristic
VRLA Battery Basic Information
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Double sulfate theory
sulfuric acid in the electrolyte acts both the ion transmission medium and the reactant
positive plate material PbO2 and negative plate material Pb are both turned to PbSO4
discharge
PbO22H2SO4Pb PbSO42H2OPbSO4charge
(lead dioxide) (sulfuric acid) (spongy lead) (sulfate) (water) (sulfate)
active material electrolyte active material active material electrolyte active material
positive plate negative plate positive plate negative plate
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Substance change in positive plate
discharge
PbO22H2SO4Pb PbSO42H2OPbSO4charge
charge
Full charge Discharge(1)
Discharge(2)Discharge(3)Re-charge
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discharge
PbO22H2SO4Pb PbSO42H2OPbSO4charge
Substance change in negative plate
charge
Full charge Discharge(1)
Discharge(2)Discharge(3)Re-charge
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Electrode reaction after full charge
Positive Plate Separator Negative Plate
Oxygen Gas
Hydrogen Gas Positive Plate
2H2O O2 (oxygen
gas) + 4H+ + 4e-
Negative Plate
4H+ + 4e- 2H2
(hydrogen gas)
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Positive Plate AGM Separator Negative Plate
O2
Oxygen recombination in VRLA Battery
The amount of spongy lead used for absorbingthe oxygen yielding at the positive plate
&
The amount of spongy lead creating at negativeplate during charge process
When they reach chemical balancethe battery will
be kept sealing.
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Process of Oxygen Recombination
1Reaction at positive plateyielding oxygen 2H2O O2 + 4H
+ + 4e-
moves towards the negative plate surface through the separator
2Reaction at negative plate 2Pb + O2 2PbO chemical reaction of spongy lead with oxygen
2PbO + 2H2SO4 2PbSO4 + 2H2O (chemical reaction of PbO with electrolyte)
to reaction
2PbSO4 + 4H+ + 4e- 2Pb + 2H2SO4 (deoxidize of PbSO4 )
to reaction to reaction
3Total reaction at negative plateO2 + 4H + 4e 2H2O
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Part I: Concept of Battery
Part II: VRLA Battery Sealing Mechanism
PartIII: VRLA Battery ConstructionPart IV: VRLA Battery Charge and
Discharge Characteristic
VRLA Battery Basic Information
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Battery appearance
Handle
Short prevention lid
Outer terminal
ABS container
Label
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Interior Structure of VRLA Battery
container & cover terminal
strap/group bar
Positive & negative platesAGM
safety valve
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structure radial structuresuit for highcurrent(power) discharge.
grids structuresuit for deepdegree discharge.
lug
frame
thickness thin plate suit for highcurrent(power) discharge.
thick platewith higher floatcharge life.
Grids
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Positive Plate
Pastelead oxide (PbO)
Formationlead dioxide( PbO2)
Negative Plate Pastelead oxide (PbO)
Formationlead (Pb)
Additionxylogen/carbon black and
barium sulfate
Plate
substance molecule weight density volume ratio compare with Pb
Pb 207.2 11.34 1
PbO 223.2 9.64 1.26
-PbO2 239.2 9.37 1.32-PbO2 239.2 9.3 1.40
PbSO4 303.3 6.29 2.64
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Keep isolation of plates
Adsorb & hold electrolyte
Channel of O2 from positive plate to negative plate
Pact the active material, avoid it loosening & shelling
Prevent dendrite shorts
Separator
Positive plate
Negative plate
Separator
Separator material pore degree() pore size (m) resistance(/cm2)
Tiny hole PVC 80 3 0.18
Tiny hole polythene 63 1 0.15
Non-woven ethene 60 12 0.21
Non-woven glass mat 65 20 0.18
AGM 90 24 0.1
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composing
H2SO4 + H20
alleviantNa2SO4
Electrolyte
electrolyte acts both the ion transmission medium and the reactant
Relationship between Specific Gravity and Open circuit voltage
OCVSG + 0.84 SG effects the voltage value & batterydischarge performance
SG effects the freezing point of electrolyte( SG=1.300, freezing point= -68. 9 )
SG effects the erosion rate of plates
0
0.2
0.4
0.6
0.8
0 .9 1 1 .1 1 .2 1 .3 1.4 1 .5
H2SO 4Density
wt.%
0
0 .2
0 .4
0 .6
0 .8
w t.% * 1 0 c on d uc tiv ity m h o s/c m s olu b ility o f Pb SO 4 *1 0
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Container
Material in common use
ABS
Polypropylene--PP
ABS container
PP container
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Part I: Concept of Battery
Part II: VRLA Battery Sealing Mechanism
Part III: VRLA Battery Construction
PartIV: VRLA Battery Charge and
Discharge Characteristic
VRLA Battery Basic Information
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Charge mode
floatstandby chargea continuous chargeprocess of battery.
cycle chargean alternate charge process of
battery.
The battery should put into charge
soon after discharge
prevent PbSO4 re-crystallized
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Constant voltage limited current charge
20
0
60
40
120
100
80
0.1C
0.08C
0.06C
0.04C
0.02C
2.4
2.3
2.2
2.1
2.0
After 100% Discharge
After 50% Discharge
Charging Current
Charged
Volume
Charging
Current
(%) (A)Charging
Voltage
(V)
0 4 8 12 16 20 24 28 32 36
Charging Time (hours)
Charging Voltage
Charged Volume
2.23V Constant Voltage Charging at 25
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Charge voltage with temperature compensation
Ste wise Com ensation
0
5
2.23V
V
2.31V
Linear Com ensation
Temperature
V
2.10
2.30
2.20
2010 4030 50
V
35
2.19
2.35
Charge
Voltage
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discharge time
1.7
1.6
1.9
1.8
2.1
2.0
1h30min106 10 20h52
0.2C 100.3C 10
0.1C 10
1min 2 3
2.0C10
1.0C 100.6C 10
0.5C 10
8
Terminal voltage(V/cell)
Constant current discharge
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0
2
4
6
810
12
14
16
18
20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Discharge time(min)
Term
ina
l
vo
ltage
(V)
Curre
nt(A)
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
kW
AmpsVoltageKilowatts
Constant discharge
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Relationship between battery dischargecapacity and ambient temperature
0
20
40
60
80
100
120
-30 -20 -10 0 10 20 30 40
Temperature
capacityC
10
low rate discharge 1h
------ high rate discharge 1h
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Discharge protection voltage
Discharge CurrentA Discharge Protection VoltageV/Cell
0.1C10 1.9
0.1C10 1.8
0.17C10 1.75
0.25C10 1.7
0.6C10 1.6
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Thank you!