Post on 21-Sep-2018
1 Distribution only by express authority of BAE Batterien GmbH
Untertitel
TITEL BAE Batterien GmbH Comparison GEL – AGM
M. Schiemann
2 Distribution only by express authority of BAE Batterien GmbH
Water decomposition lead acid batteries
2 V
1.227 VOxygen evolution(O2- ½ O2 + 2e-)
Hydrogen evolution(2H+ + 2e- H2)
Positive electrodeNegative electrode
Oxygen reduction(½ O2 + 2e- O2-)
Pb/PbSO4electrode
PbSO4/PbO2electrodeWater
decompositionvoltage
- 0.2 0- 0.4- 0.6- 0.8 1.4 1.6 1.8 2.0 2.2 U in V
Gas
evo
lutio
n ra
te
Water decomposition is a secondary reaction in lead-acid and nickel/cadmium batteries, which can’t be avoided!
3 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Minimal requirements for recombination
process: • Internal oxygen cycle necessary for recombination
of hydrogen and oxygen gas
• Oxygen – development at the positive electrode
• Hydrogen – development at the negative electrode
• Fast gas transport (oxygen) is for
recombination at the negative electrode necessary
• No dilution of gas inside fluid electrolyte possible
• Fast gas transport only by diffusion possible, if free volume
inside electrolyte is available (Gel or AGM)
OH-
Elektrolyt gebunden im Gel und/oder Vlies
OH-
H+ H+
O2 O2
O2O2
"Neg
ativ
e E
lekt
rode
" al
sAno
de
"Pos
itiv
e El
ektr
ode"
als
Kat
hode
ÜberdruckventilValve
Electrolyte fixed as Gel or AGM
Neg
ativ
e el
ectro
de
Pos
itive
ele
ctro
de
4 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
FREE Space inside electrolyte
Two technologies possible:
Gel 3 – 10 % SiO2 (electrolyte fixed by silica)
flies mat (AGM absorbent glass mat) separators
5 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology Free space inside electrolyte:
GEL: • from shrinking during solidification process results cracks inside the gel, which
makes fast gas transport between the plates possible.
AGM: • Fluid electrolyte is fixed by capillary power. The small pores of the fleece are
filled with electrolyte, while larger pores are available for gas transport
95% - 98 % efficiency of internal recombination cycle
6 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology
Elektrolyt gebunden im Geloder Vlies
2H2+
½ O2
nega
tives
Akt
ivm
ater
ial
Separator bei Gelbatterien
Risse im Gel oder Poren im Vlies
2H2O
Lade
rese
rve
2e-
posi
tiver
Abl
eite
r
nega
tiver
Abl
eite
rGleichrichter
e- e-
e- e-
posi
tives
Akt
ivm
ater
ial
2e-
ÜberdruckventilValve
Charger
Pos
itive
con
duct
or
Neg
ativ
e co
nduc
tor
Electrolyte fixed as Gel or in absorbed glass mat
Separator for Gel batteries
Pores inside AGM material or cracks inside Gel
7 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: Recombination process Positive Electrode:
Development of oxygen gas obtained by water decomposition:
Negative electrode:
Development of hydrogen ions
2 H2O → O2 + 4H++ 4e-
positive electrode negative electrode
Transfer of oxygen gas to the negative electrode through the free space
8 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: Recombination process Negative electrode:
Recombination of the oxygen gas – negative electrode develop continually lead
sulphate (during battery life partially discharged)
2 Pb + O2 → 2 PbO
PbO + H2SO4 → PbSO4 + H2O
Negative electrode: Recharge of lead sulphate to lead PbSO4 + 2H+ +2e- → Pb + H2SO4 The recombination process at the negative electrode is accompanied by heat development drying and aging of the battery
9 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: Recombination process
H2O 2H++ ½ O2
Pb PbO PbSO4 + H2OH2SO4
Pb + H2SO4
Positve plateNegative plate
Negative plate
Transfer troughfree volume
10 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: GEL Construction GEL
• Network of silicic acid particles with high surface (200 m²/g). The GEL can
transferred to a fluid consistence by mixing.
Pore system:
• Between the network particles of silicic acid particles is a system of pores with
a diameter from 0,1µ to 1µ
Fixing of electrolyte:
• Acid is fixed by capillary power and high surface of the particles and is
changed to GEL (also well know from the principle of solid paint).
11 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: GEL Battery construction:
• Filling at fluid consistence like acid.
Then permanent mixing and gelling
with acid during charge of batteries.
Si Si
OO HH
O
Si
H H O
Si
12 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: GEL
GEL Cracks inside GEL as gas channels Electrode and Separator
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Valve regulated/sealed lead acid batteries
Technology: AGM Construction AGM
• Woven net of glass fibers with different thickness (0,25µ to 3µ)
Pore system
• Between the fibers is a system of pores with a diameter of 1µ to 10µ
Fixing of electrolyte
• The sulfuric acid is absorbed and fixed by the capillary power like with a
sponge
14 Distribution only by express authority of BAE Batterien GmbH
Valve regulated/sealed lead acid batteries
Technology: AGM Battery construction
• The glass mat is assembled between the
plates during plate staking with a high
pressure to obtain the good contact
between the active mass and the glass
matt. Acid is filling with a filling grade of 95
% after assembly.
Gas channel Sulfuric acid as fixed electrolyte Fibers
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Construction and structure of AGM
Technology: AGM
plate set negative plate
positive plate
positive grid
negatives grid
glass fibre separator with fixed electrolyte
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Construction and structure of OPzV
Technology: GEL
Negative plate Negative grid
Positive grid Positive plate
Plate stack
17 Distribution only by express authority of BAE Batterien GmbH
Benefits of BAE flash arresting valve
Technology: Valve • Applied for OPzV single cell an bloc
batteries and OGiV single cells
• Secure opening at 120 mbar+-30 %
• Secure closing above 50 mbar
• high precision rubber part with a lip
seal
• Flash-arresting by a micro porous frit
• Perfect gas drying, no acid fumes
outside
• The valve is securely screwed into the
bayonet opening
18 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
GEL AGM
Pore size 0,1µ to 1µ like positive/ negative mass (lead to high
capillary power)
1µ to 10µ (low capillary power)
SiO2 weight / acid weight Up to 10 % SiO2 Up to 10% SiO2
Structure
Si-O-O-Si - molecular chains 0,25µ to 3µ thick SiO2 fibres
Elasticity / plasticity plastic, keeps contact to plates Elastic in a small range
Location
contact to box, includes straps only between the plates
Additional micro-porous separator
Yes no
Technology comparison:
19 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
Acid stratification, obtained by low capillary power:
1,18
1,20
1,22
1,24
1,26
1,28
1,30
0 2 4 6 8 10 12
acid
gra
vity
[kg
/l]
number of cycles
vented, above
AGM, above
GEL, above
GEL, below
AGM, below
vented, below
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Comparison Gel and AGM Batteries
Technology comparison: + AGM - + GEL -
Pore size 0,1 µm 5 µm 0,3 µm 0,1µm 0,5 µm 0,3µm
AGM GEL Internal resistance new cell 1,4 mΩ 1,55 mΩ
Internal resistance after 10% water loss 2,4 mΩ 1,65 mΩ
wat
er lo
ss [%
] ove
r life
tim
e
21 Distribution only by express authority of BAE Batterien GmbH
Technology comparison:
Comparison Gel and AGM Batteries
GEL AGM
Internal resistance average, because GEL and the separator is present
very low, ideal for UPS systems
Power density average average electrical losses, also low space requirement
good low electrical losses and low space requirement
Cycle life time
excellent, because no acid stratification, small pores, mass protection at tubular plates by gauntlets
average, limitation by acid stratification at large cells and lack of contact
Costs (initial ivest) average, besides the separator the GEL costs are additional
low, because the glass-mat is cheaper than the microporous separator
22 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
GEL AGM Total cost over life time
Lower related to AGM, due to higher life time (design life time and operational life time) and cycle stability
Higher related to GEL (especially tubular plate design) due to the danger of fast capacity decrease (PCL2 effect)
Design specialities
No cell’s height restriction, cell design with positive tubular and flat/grid plates are possible with GEL
Plate thickness has to be in very low tolerance; AGM batteries are possible only with flat/grid plates Cells height not higher than nearly 350 mm, to prevent non uniform acid distribution obtained by low capillary power
Technology comparison:
23 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
Technology comparison: Thermal runaway simulation
GEL 6V 68Ah, aged, at 2,6V/cell overcharge
0
1
2
3
4
5
6
0 5 10 15 20 25 30
charging time / h
curr
ent -
equ
ival
ent /
A
0
10
20
30
40
50
60
tem
pera
ture
/ °C
temperature
oxygenrecombination
hydrogen
current
• Tmax = 50°C after 28 h • Total current increases to 5A • 6V 68Ah GEL
AGM 6V 68Ah, aged, at 2,6V/cell overcharge
0
5
10
15
20
25
30
35
40
45
50
0 1 2 3 4 5
charging time / h
curr
ent -
equ
ival
ent /
A
0
10
20
30
40
50
60
70
80
90
100
tem
pera
ture
/ °C
temperature
current
hydrogen
oxygenrecombination
• Tmax = 80°C after 4,5 h • Total current increases to 40A • 6V 68Ah AGM
24 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
life time
stability of capacity
thermal-run-awayresistance
cycle life time
tubular platestechnologydeep discharges
internal resistance
high currentbehaviour
costs
AGMGEL
Technology comparison:
25 Distribution only by express authority of BAE Batterien GmbH
BAE Gel Products - SECURA OPzV cell
Capacity range: 100 to 3250 Ah Operational life: 20 years (stand-by) IEC 60896-21 – cycles: >1500 Float voltage: 2.25 V±1% Acid density: 1.24 kg/l Electrolyte fixed in: GEL by fumed Silica Valve: 120 mbar Plate type: tubular/flat Alloy positive grid: PbCaSn Pole bushing: 100% tight Container/lid: high impact SAN
UL-rating 94 HB; V-0 on request
Connectors: bolted flexible or solid insulated copper connectors
Installation: vertical, horizontal on request
26 Distribution only by express authority of BAE Batterien GmbH
BAE Gel Products - SECURA OPzV BLOCK Capacity range: 50 to 900 Ah Operational life: 18 years (stand-by) IEC 60896-21 – cycles: >1500 Acid density: 1.24 kg/l Float voltage: 2.25 V±1% Electrolyte fixed in: GEL by fumed Silica Valve: 120 mbar Plate type: tubular/flat Alloy positive grid: PbCaSn Pole bushing: 100% tight Container/lid: high impact SAN
UL-rating 94 HB; V-0 on request
Connectors: bolted flexible or solid insulated copper connectors
Orientation: vertical, horizontal on request
27 Distribution only by express authority of BAE Batterien GmbH
Comparison OPzV Gel and AGM Batteries
BAE OPzV GEL AGM Positive plate – tubular plate Negative plate – Flat plate/grid plate
Gauntlet encase and protect active mass • No mass softening (PCL2 effect) by
counter pressure from gauntlet • High mass reserve, reduce mass stress
during cyclic operation Centered lead road with high cross section • High corrosion life time • Homogeneous allocation and discharge
of active mass
Mass pasted into grid Softening of active mass during cycling easier possible (PCL2 effect) Limited mass per plate • No cyclic stability • Limited capacity
Technology comparison:
28 Distribution only by express authority of BAE Batterien GmbH
BAE Accelerated Life Time Test
Test results accelerated aging test: Initial requirements:
• 15 years at 23 °C corresponding to 250 days
at 62,8 °C
• (acc. to Arrhenius approach)
• At the end of temperature : Seismic test (simulation of
earthquake and aircraft crash)
Test procedure:
• Every 50 days 3h capacity test to 1,75 V/cell at room
temperature
• Float current, growth of poles were measured frequently
• Tear-down analysis at the end of the test
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Test results accelerated aging test:
BAE Accelerated Life Time Test
020406080
100120140160180
0 50 100 150 200 250 300 350 400 450 500
3h c
apac
ity a
t 20°
C /
%
Days on float charge (2,25V at 62,8° C) 16OPzV 2000 7OPzV 490 4OPzV 200
Seismic test
19.4 years 34.8 years Simulated life time at 20°C:
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Test results accelerated cycling test: • Procedure: 3 h discharge with 2 x I10 (here 86 A) equals to 70 % DoD
• Full charging for 21 h at 2.40 V
• every 50th cycles capacity test until Crt = 0.8 (EOL criteria)
Full cycle test acc. to 60896-21 (IEC 896-2)
> 1700 cycles corresponds to 4.6 years life time with daily (at 70% DOD)!
31 Distribution only by express authority of BAE Batterien GmbH
Test results accelerated cycling test at 40°C/104 °F:
Solar cycle test acc. to IEC 61427:2002-04
Phase A: (40 °C)
Disch. 9 hrs with I10
Charge 3 hrs with 1.03 I10
Disch. 3 hrs with I10
Phase B: (40 °C)
Disch. 2 hrs with 1.25 I10
Charge 6 hrs with I10
Complete charge (40 °C)
49 x or
Ue < 1.5
Capacity test C10 at 20 °C
Finished when C10<80%
100 x
Phases A and B in scheme
Result: Cycle life as number of A+B - cycles
SOC
in %
Number of cycles
SOC 75 % 100 % SOC = DOD 25 %
SOC 10 % 40 % SOC = DOD 30 %
32 Distribution only by express authority of BAE Batterien GmbH
Test results accelerated cycling test at 40°C/104 °F:
Thermal chamber for the life time test
Solar cycle test acc. to IEC 61427:2002-04
33 Distribution only by express authority of BAE Batterien GmbH
Test results accelerated cycling test at 40°C/104 °F:
Solar cycle test acc. to IEC 61427:2002-04
80%
90%
100%
110%
120%
0 150 300 450 600 750 900 1050 1200 1350 1500 1650 1800 1950 2100 2250 2400 2550 2700 2850 3000 3150 3300
Cap
acity
as
C 1
0h (
20°C
)
Cycles ( Solar test ) @ 40 °C
Slope of available capacity measured as C 10h after 150 solar cycles (1 block of A+B cycles) at T reference = 20 °C
6* 2 V 5 PVV 350
34 Distribution only by express authority of BAE Batterien GmbH
Comparison Gel and AGM Batteries
BAE OPzV GEL AGM IEC cycles >1500 cycles ~700
Design Life Cell: 20 years Block: 18 years Ø 13 years
Float voltage per cell (driven by acid gravity) 2,23V Ø 2,27 V
Needed installation space Higher Low
Weight (lead weight driven) High Low
Costs of acquisition 100 % ~ Ø 70 %
Technology comparison:
Thank you for your attention