Lead Acid
Batteries
Optima Batteries
Acquired in November 2000 by JCI
•Plant located in Aurora, Co
•Optima Batteries utilizes six sigma
methodology
•TS 16949 Certification
•Worldwide distribution
Lead Acid Battery Basics
Battery Basics-Definitions
•
A battery is a device that converts chemical energy into electrical energy.
•
A cell is the basic electrochemical unit.
•
A battery consists of one or more cells connected in series, or in parallel, or both.
•
Batteries, in general, are classified as primary, i.e., non-rechargeable, or secondary, i.e.,
rechargeable. Zinc-manganese dioxide, LeClanche’ or alkaline, cells are primary batteries. Leadacid batteries are secondary batteries. Advanced secondary batteries include nickel metal
hydride and lithium ion.
•
Types of lead-acid batteries include round or cylindrical and prismatic or rectangular cells.
•
Lead acid batteries can be classified further as wet, i.e., flooded, or VRLA (valve regulated lead
acid) which includes gel and AGM (absorbed glass mat).
Battery Basics-Cell Chemistry
D
•
At the positive plate: PbO2 + 4H+ + SO42- + 2e-
C
PbSO4 + 2H2O
D
•
At the negative plate: Pb + SO42-
PbSO4 + 2e-
C
D
•
Total Cell Reaction: PbO2 + Pb +2H2SO4
2PbSO4 +2H2O
C
Note: Active materials include lead dioxide, lead and sulfuric acid.
Note: Battery OCV depends only acid specific gravity and the cell voltage can be
approximated by V = 0.84 + acid specific gravity.
Battery Basics-Cell Chemistry
Additional Reactions of Significance
C
•
Oxygen Reaction Cycle::
½O2 + Pb
PbO
C
PbO + H2SO4
PbSO4 + H2O
Note: Oxygen reaction cycle is a benchmark characteristic of VRLA batteries. It is more
pronounced with AGM than with gel constructions.
•
Severe Overcharge Reaction: 2H2O
C
O2 + 4H+ + 4e-
Note: This results in water loss due to venting of O2 and can be life limiting.
•
Positive Grid Corrosion: Pb + 2H2O
PbO2 + 4H+ + 2e-
C
Note: This results in water loss and can be life limiting.
Battery Basics-Cell Schematic
Load
Power
e-
e-
Electron Flow
Electron Flow
─
Electron
Loss
Electron
Gain
Discharge
Pos Ions
Neg Ions
Electron
Gain
Oxidation
+
Cathode
Reduction
Neg Ions
Reduction
Pos Ions
Cathode
+
Anode
Oxidation
─
e-
Anode
e-
Electron
Loss
Charge
Battery Basics-Manufacturing
Wet/Gel/AGM
Manufacturing-Wet/Gel
OxideBarton or
Ball Mill
Paste Mixing
Lead Alloy
Grid
Production
Container
and Cover
Injection
Molding
Container
Hole Punch
Element
Insertion
COS-Cast
On Strap
Sulfuric
Acid
Sodium
Sulfate
Container
and Cover
Heat Seal
Intercell
Welding
Gel
Post Burn
Pressure
Test
Phosphoric
Acid
Plate
Pasting
Plate Curing
Element
PreparationEnveloping
& Stacking
Yes
No
Silica
Water
Acid Mixing
Acid Filling
Decoration
and
Shipping
HRD-High
Rate
Discharge
OCV
Formation
Manufacturing-AGM Flat Plate
OxideBarton or
Ball Mill
Paste Mixing
Lead Alloy
Grid
Production
Container
and Cover
Injection
Molding
Container
Hole Punch
Element
Insertion
Container
and Cover
Heat Seal
Intercell
Welding
Sulfuric
Acid
Plate
Pasting
Plate Curing
Element
PreparationStacking
COS-Cast
On Strap
Post Burn
Pressure
Test
Sodium
Sulfate
Water
Acid Mixing
Acid Filling
Decoration
and
Shipping
HRD-High
Rate
Discharge
OCV
Formation
Manufacturing-AGM Spiral Wound
OxideBarton or
Ball Mill
Paste Mixing
Lead Alloy
Grid
Production
Container
and Cover
Injection
Molding
Acid Mixing
Plate
Pasting
Plate Drying
COS-Cast
On Strap
Acid Filling
Sodium
Sulfate
Sulfuric
Acid
Decoration
and
Shipping
HRD-High
Rate
Discharge
Element
Partial
Insertion
Element
Insertion
Container
and Cover
Heat Seal
Water
Element
PreparationWinding
Pressure
Test
Post Burn
OCV
Formation
Grid Production Processes
Lead Alloys
Gel
Battery Type
Spiral AGM
Wet & Flat Plate AGM
Book Mold
Positive and
Negative
Expanded
Metal
Positive and
Negative
Concast
Negative
Perforated
Sheet
Positive and
Negative
Grid
• Grid
– Primary function is structural to support the active
material and carry the current
– Secondary function is electrochemical in nature as
the grids participate in redox reactions at the
positive and negative active material interface, i.e.,
corrosion
– Desired features
• Low resistivity
• Strength
• Corrosion resistance for positives
• High purity
Grid Alloy
•
Grid Alloys
– Lead/Lead Tin
• Soft, generally too weak to use in flat plate designs
• Low gassing
• Low self discharge
• Continuous grid making processes for spiral wound design
– Lead Calcium Silver
• Low gassing
• Low self discharge
• Slower processing compared to lead antimony
– Lead Antimony
• High gassing
• High self discharge
• Easily cast and fabricated
• Good cycle life
Paste
• Paste
– High Paste Density
• Stronger material with less shedding in wet or gel designs
– Shedding is not an issue with AGM designs because of
the compression of the separator against the plates and
the tight interference fit with the cell container
• Better contact with the grid interface
• Reduced initial capacity which cycles up to give longer
service life in cycling applications
• Lower efficiency at high discharge rates
– Low Paste Density
• Initial capacity is high
• Higher efficiency at high discharge rates
• Poorer service life in cycling applications
Separator Distinctions
Separator
Gel
Battery Type
AGM
Wet
Polyethylene
or Polyvinyl
Chloride
Sheets
Polyethylene
Envelopes
100% Glass
Microfiber or
GlassPolyolefin
Composite
Sheets
Separator Sources
• Separator
– Wet
• Microporous polyethylene envelopes
– Extrusion formed
– Backweb thickness
– Oil content
– Silica content
– Gel
• Microporous polyethylene sheets
• Polyvinyl chloride sheets
– AGM
• Glass microfiber sheets
– Compression is an important design feature
– Glass-polyolefin composites under development
– Made on conventional paper making equipment
Separators
From BCI Website
Wet
Optima
Wet or flooded vs AGM
IT’S THE SEPARATOR
AGM = Absorptive Glass Mat
Oxygen
Gas
Hydrogen
Gas
Flooded is “Vented”
Gas exchange with
surroundings
Oxygen reacts at the
negative plate
resulting in negligible
water loss
Negative Plate
Positive Plate
Separator
AGM is “Sealed”
Valve regulates
pressure and
vacuum
Oxygen Gas
Positive Plate
AGM Separator
Negative Plate
Wet/Gel Battery Construction
From BCI Website
Optima AGM Battery Construction
Optima has lower internal
resistance compared to flat plate
batteries
•Optima has less internal parts (~30)
vs traditional batteries (120+)
•Optima has over the partition, solid
lead connectors vs through the
partition inter-cell welds
Element Characteristics
• Factors affecting internal resistance of the battery
– Size of lead conductors
– Plate surface area
– Plate spacing
– Separator resistivity
– Electrolyte type
• Gel has higher resistance than flooded or
AGM designs which negatively impacts high
rate and cold performance
– Electrolyte concentration
– Temperature
Container/Cover Design
• Cylindrical cells provide superior
mechanical structure to battery
– Eliminates cell bulge
– Permits higher valve
pressures, 7-8 psi, compared
to flat plate, 1-5 psi
• Flat plate batteries can
experience end wall bulge when
pressure builds up on charge
resulting in loss of performance
OPTIMA
Performance
What is Optima?
•Advanced lead acid battery
technology
•Spiral wound cells
•Sealed AGM design
•Current OE applications
–Daimler Chrysler
•Minivan Diesel (Graz, Austria)
•PT Cruiser Diesel (Toluca, Mexico)
•Jeep Liberty Diesel (Toledo, USA)
–FORD
•GT
–GM
•Silverado Military Truck
Orientation Flexibility
Non-Spill
•Can be installed in almost any orientation/position
•Air shippable like gel and flat plate AGM
Vibration Performance
The Optima Advantage
Vibration Resistance
• The Optima Group 31 runs
in excess of 9,000 hours
at 5G’s
Vibration @ 5G's in Hours
12000
10000
8000
Why?
• High degree of separator
compression, and tight
interference fit between
the element and cell wall
6000
• Less parts, two plates per
cell vs. multiple plates in
flat plate designs
0
4000
2000
Optima
• No intercell welds to fail
Source: AGM Development Team
Comp A
Flooded
Comp B
Flooded
Vibration @ 5G's in Hours
Comp C
Flooded
Gassing Characteristics
• Gassing
– Less than flat plate/prismatic design
• Why?
– Higher purity materials – 99.99% pure lead
– Alloys – Optima uses a binary tin lead alloy
compared to a flooded battery that uses a multi
component alloy (silver, tin, calcium, aluminum,
etc… less impurities)
– Oxygen reaction cycle
Source: AGM Development Team
OCV Stand Loss
Optima batteries show a higher OCV on stand compared to flooded batteries. OCV does not
tell the whole story. You also must look at the OCV vs SOC relationship.
13.50
13.00
OCV
12.50
12.00
11.50
11.00
10.50
10.00
0
Optima DC
OCV STAND LOSS
200
Optima SLI
400
600
800
Days @ 25 C
Flooded Gr 34 SLI
1000
1200
Flooded Gr 27 DC Marine
High Rate Cold Performance
• More Power
− Optima has more high rate
power (CCA) than comparably
sized flat plate batteries
• Why?
− Higher specific acid gravity
than flooded
− Lower internal resistance than
flooded due to thinner positive
plates than flooded and no
inter-cell welds
High Rate Cold Performance
L o w e r in te r n a l im p e d a n c e g iv e s O p tim a (5 0 A -h r s ) b e tte r p o w e r o u tp u t th a n h ig e r r a te d
c a p a c ity flo o d e d (7 2 A -h r s ).
T h is le ts O p tim a c o m p e te w ith h ig h e r r a te d flo o d e d .
5000
4500
High power, more run time
gives Optima more available
energy
Pow er (W atts)
4000
3500
3000
2500
2000
1500
1000
0
20
-20Degrees F/300 A Discharge
40
60
80
R u n T im e (s e c )
O p tim a G r 3 4 S L I
F lo o d e d O E G r 6 5
100
120
140
High Rate Cold Performance
Higer voltage/lower internal impedance give lower capacity Optima (900 CCA/155 min
RC) better power output than higer capacity JCI flooded (950 CCA/195 min RC)
10000
Power (Watts)
9500
9000
8500
8000
7500
7000
6500
6000
0
5
10
15
20
Run Time (sec)
Optima 900 CCA
Flooded 950 CCA
25
30
High Rate Cold Performance
O R M C C A P o w er at 0 D eg rees F
8000
P o w e r (W a tts )
7000
6000
5000
4000
3000
2000
1000
0
Op tim a-900 A
FL 1-700 A
FL 2-700 A
Po w e r @ 30 S
A GM 1-720 A
Po w e r @ 60 S
FL 3-700 A
FL 4-700 A
Performance on Charge
Optima's reserve capacity recovery is up to 25% more than flooded
product indicating a better charge acceptance.
FL2
FL1
Test Conditions
32F 13.3V
Optima
FL2
32F 14.4V
FL2
FL1
80F 13.3V
FL1
Optima
Optima
FL2
80F 14.4V
0
20
40
60
Percent Return Based On Previous RC
Optima
FL1
FL2
80
FL1
Optima
100
Repetitive RC Cycling @ 80 F
Optima construction with high density active materials and tight spiral wound
compression on the plates gives excellent cycle life. No cycle down and more capacity
throughput.
240
Reserve Capacity (Min)
220
200
180
160
140
120
100
80
60
40
20
0
0
100
200
300
400
Cycle Number
Repetitive Reserve Capacity Cycle Life
155 Min RC/75 A-hr C/20 Optima Group 31
185 Min RC/98 A-hr C/20 Flooded Group 31
Field Returns
Median Automotive Battery Life
70
Hot Weather
Mild Weather
Life (Months)
60
50
40
AGM has longer
life in warm
temperatures
Battery life
increases with
cooler temperatures
30
20
Hot
Weather
Decreasing Temperature
Mild
Weather