Transcript Presentation

Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Principles of Radioactive Tracing
Method
The radioactive tracing method is based on replacing in the
electrolyte some of the 32S ions by the 35S isotope (bettaemitter). Then the plates are dipped into the new electrolyte
and polarized. They are extracted from the cell and the
distribution of the “heavy” PbSO4 throughout the plates is
analyzed. This is possible by special betta-radiation detectors.
The method provides an unique tool to investigate the
processes related to the electrolyte stratification effect during
operation of LAB.
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes
Photovoltaiques, PhD thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France .
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Principles of Radioactive Tracing
electrolyte stratification during operation of LAB.
distribution of PbSO4 across the battery plates.
some of the 32S atoms are replaced by 35S isotope (a b-emitter).
the electrolyte contains some “heavy”H2SO4.
the distribution of 35S - traced by b-radiation detectors.
35S
scanner
b
sample
e-
polymer screen with BaFBrEu2+
F + e(BaFBr -)
Eu2+ + b
Eu3+
BaFBr - + photon
BaFBr + e- (Eu2+) + photon
He-Ne laser, 10 mW
detector
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes
Photovoltaiques, PhD thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
SCIENCES
Image of one side of a positive electrode
After the first discharge
After the first recharge
the plate is dipped in the electrolyte,
discharged,
recharged again.
Source: F. Mattera, D. Desmettre, J. Martin, Ph. Malbranche, J. Power Sources, 113 (2003) 400-407.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Influence of cycle number on sulphation
charged positive plate after:
2 cycles
20 cycles
20 cycles, washed 40 cycles, washed
Intensity scale
substantially higher content of PbSO4 in the bottom part of the plates
than in the upper one (batteries with electrolyte stratification).
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes Photovoltaiques, PhD
thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Softening and shedding of PAM
charged positive plate after 40 cycles.
The plate is rinsed with water.
softened PbO2 particles are eliminated from the surface by rinsing,
some hard PAM around the grid bars, uneven PbSO4 distribution.
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes Photovoltaiques, PhD
thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Softening and shedding of PAM
Discharged
positive plate:
Before
cycling
After
40 cycles
more severe shedding of PAM in the bottom part of the plates
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes Photovoltaiques, PhD
thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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Positive active mass degradation
charged positive plate after 40 cycles.
the plate is rinsed with water.
PAM
grid
Irreversible sulphation in the interface PAM/grid
Source: Fl. Mattera, Etude des Modes de Vieillissement des Accumulateurs au Pb Utilises dans les Systemes Photovoltaiques, PhD
thesis, 29 Octobre 1999, Institut National Polytechnique de Grenoble, France.
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
ACADEMY OF
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GENERAL CONCLUSIONS:
Major battery problems
(solved or to be solved by: technological improvements,
new materials or test/control procedures and devices)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Corrosion (open), grid expansion (solved).
Active material shedding (open).
Passivation (still a problem in some applications).
Sulphation, stratification (still a problem in some applications).
Antimony poisoning (solved).
Positive plates failure by Pb-Ca alloys (still a problem).
PCL 1 (solved).
PCL 2 (still a problem in some applications).
PCL 3 (solved).
Recombination problems, drying out (open).
TRAE (open).
12. Other problems??…. – you may add them as open or as solved!!!
Centre of Excellence POEMES, IEES (CLEPS), BULGARIAN
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Acknowledgments
• EC (specific program “Energy, Environment and Sustainable
Development – Part B: Energy program”, contract No.
NNE5/2002/18);
• A. Kirchev, A. Gigova, M. Stoycheva, S. Vassilev and D. Pavlov
for their contribution in the preparation of this course.
SCIENCES