Regeneration of sealed accumulator batteries

1. Regeneration cost:
20—30 %
from price of
a new battery
Lifetime exhaustion
RECYCLING
RELEVANCE OF THE PROBLEM
Mobile TeleSystems OJSC exploits a
lot of
sealed lead-acid
accumulator batteries Necessary to renew:
up to 10% per year
Cost of replacement for
one Accumulator
(12 V, 90 A*h):
15—20 thous. rub.
Presentation
Page 1
Other defects
• electrode corrosion (+);
• damage of contact layer;
• evaporation of water and/or acid;
• short circuit
up to 20%
Sulphation:
more than 80%
of batteries should be
replaced
Reason of failure
May be
regenerated
up to ratings
3240 rub.

2. LEAD-ACID ACCUMULATOR:
HOW DOES IT WORK
Presentation
Page.2
PbO2
Positive electrode:
lead dioxide
FULLY CHARGED
ACCUMULATOR
DISCHARGED
ACCUMULATOR
Pb
Negative electrode:
spongy lead
H2O + H2SO4
Electrolyte:
sulfuric acid solution
PbSO4
Positive electrode:
lead sulfate
PbSO4
Negative electrode:
lead sulfate
H2O + H2SO4
Electrolyte: less acid, more
water

3. MAIN PHYSICO-CHEMICAL PROCESSES
IN LEAD-ACID ACCUMULATOR
Presentation
Page 3
Accumulator discharge results in formation of a lead sulfate layer of fine-pored structure on both electrodes, and the
strength of sulfuric acid in electrolyte solution diminishes.
During accumulator charge the sulfate dissolves and then deoxidizes till metal lead on the negative and till lead oxide
on positive electrode, and acid strength grows.
per one cell

4. MAJOR DEGRADATION CAUSE FOR LEAD-ACID ACCUMULATOR CHARACTERISTICS:
SULPHATION
of negative and positive electrodes
Presentation
Page 4
Degradation of accumulator plates due to sulphation
SWEL Energy Ltd. has worked out an innovative technology for desulphation
and regeneration of battery performance during its electrical charge
Partial sulphation
Deep sulphation
Very deep sulphation

5. REGENERATION TECHNOLOGY and PROCEDURE
Internal resistance of lead-acid accumulator :
 Active r. — depends upon accumulator structure and its charge condition — cannot be reduced
 Polarization r. — is determined by electrochemical processes in the accumulator — can be reduced
Presentation
Page 5
Oscilloscope traces for charging voltage and current
Voltage
CurrentMinimal
internal
resistance
SWEL Energy Ltd. has worked out an algorithm of accumulator charge by small energy ‘portions’, that provides
separation in time of electrical and chemical processes.
As a result the polarization component of accumulator internal resistance declines almost to zero.
Regeneration algorithm provides optimal
speed of sulfate dissolution and accumulator charge at
minimal internal resistance

6. PRACTICAL APPLICATION EXPERIENCE Presentation
Page 6
During the last two years SWEL Energy Ltd. has successfully executed a number of projects on performance
regeneration of lead-acid accumulators of different manufacturers.
1. Under contract with Rostelecom OJSC we regenerated accumulator batteries for 3 exchange stations:
• “Gorky-10» in Moscow region, Odintsovsky microdistrict, Gorky-10 settlement, 31
(Sonnenschein A412/50 A batteries);
• Switching substation-597 “Maliye Vyazyomy” in Moscow region, Odintsovsky microdistrict, Maliye
Vyazyomy settlement, Petrovskoye highway, 3а (Oerlikon COMPACT-POWER 12CP50 batteries);
• Non-commercial partnership of gardeners “Droujba” in Moscow region, Odintsovsky microdistrict,
Zhavoronky settlement (Oerlikon COMPACT-POWER I 2CP50 batteries).
All accumulators have been functioning nominally during 20 months (since April 2013).
2. Under contract with Rostelecom OJSC branch in Novgorod we regenerated Delta accumulators (50 Ah).
All batteries have been functioning nominally during 8 months (since 2014).
3. Under contract with MGTS OJSC we regenerated Sonnenschein accumulators (65 Ah) for one exchange
station.
All batteries have been functioning nominally during 1 year (since November 2013).
4. Under contract with Ecomotors Ltd. we regenerated Sonnenschein and Tudor UPS 12V360 batteries (88 Ah).
All batteries have been functioning nominally in cyclic operation (30—50% discharge) during 2 years
(since December 2012). Since May 2014 a part of batteries has been functioning in off-nominal traction
mode (100% charge/discharge cycle) providing charge-discharge ratings.
5. Under contract with Cleanford Ltd. (Moscow region, Krasnogorsk) we regenerated Sonnenschein
accumulators (2V/225 Ah).
During 10 months (since February 2014) all batteries have been functioning daily as normal with 100%
discharge, providing charge-discharge ratings.

7. Regeneration of accumulator batteries TUDOR UPS 12V360
under contract with Mobile TeleSystems OJSC
Presentation
Page 7
In October-November 2014 SWEL Energy Ltd. regenerated 198 batteries Tudor UPS12V360 under contract with
Mobile TeleSystems OJSC, which Mobile TeleSystems OJSC had used for 8 years as part of uninterruptible power
systems.
Voltage ‘sag’
It was identified that during operation
all batteries had been more or less
subjected to sulphation (huge voltage
‘sag’ during discharge, decrease of
discharge capacity in comparison
with nameplate capacity).
After processing and regeneration the
accumulators demonstrated charge-
discharge characteristics generally
equivalent to nameplate values.

8. Regeneration of accumulator batteries TUDOR UPS 12V360
under contract with Mobile TeleSystems OJSC
Presentation
Page 8
After regeneration all regenerated batteries were tested in 15-minute discharge mode. Consequently, 18 batteries
were considered defective that amounted to 9% of the total number of batteries, delivered for regeneration. Such
defective ratio should be considered as very low.
 After regeneration 91% of batteries
were recognized usable for further
operation;
 The technology worked out by SWEL
Energy Ltd., is very likely to provide
complete regeneration of work
capacity for accumulators suffered from
deep sulphation.
 Regenerated batteries display
nameplate characteristics during
discharge by small, medium and high
current;

9. LIFE TESTS Presentation
Page 9
In 2012—2013 SWEL Energy Ltd. carried out life tests of regenerated accumulators with its discharge by heavy
current 3С (depth of discharge 30%).
As shown on the figure, the lifetime of batteries regenerated with the help of SWEL Energy Ltd. technology,
corresponds to ratings delivered by battery manufacturers.
Test results
Average values
Initial
capacity
Measured capacity
(% to initial discharge capecity)