Journal of Applied Electrochemistry

, Volume 21, Issue 5, pp 409–414 | Cite as

Dynamic simulation of the charge-discharge characteristics of the sodium-sulphur cell

  • H. Kawamoto
Papers
  • 81 Downloads

Abstract

A dynamic model of the porous sulphur electrode including diffusion of the reactant is developed to simulate charge-discharge characteristics of the sodium-sulphur cell and transient behaviour of the cell after termination of operation. From the results of investigations the following are clarified: (1) sodium ion concentration on the solid electrolyte side is low during charge, on the other hand, it is high during discharge; (2) an insulating film of sulphur is formed at the surface of the solid electrolyte in the deeply charged stage. This results in an increase of the cell resistance and thus restricts charge acceptance; (3) the resistance in the single phase region is larger than that in the two phase region; and (4) open circuit voltage in the single phase region, observed after termination of operation, is not equal to the equilibrium value but gradually approaches it according to the concentration relaxation. These characteristics agree well with experimental results.

Keywords

Sodium Sulphur Dynamic Simulation Open Circuit Solid Electrolyte 

Nomenclature

a

effective surface area per unit volume of the graphite matrix (cm2cm−3)

c

molar concentration (mol cm−3)

D

diffusion coefficient of electrolyte, Na2S (cm2s−1)

D+,−

diffusion coefficient of sodium ion and sulphur ion (cm2s−1)

F

Faraday constant (96 487 C)

I

total current (A)

J

current density (A cm−2)

jex

exchange current density (A cm−2)

Kp

surface polarization resistance coefficient (Ω cm2)

L

longitudinal length of sulphur electrode (cm)

OCV(t)

quasi-open circuit voltage observed after termination of operation (V)

p

porosity of sodium polysulphide melt

R

resistance of the cell (Ω)

Ro

resistance of the solid electrolyte, the sodium electrode and electronic components (Ω)

r

radial coordinate (cm)

ri

inner (solid electrolyte side) radius of sulphur electrode (cm)

ro

outer (metal container side) radius of sulphur electrode (cm)

t

time (s)

t+

transference number of sodium ion

V

volume of sulphur electrode, π(r o 2 r i 2 )L (cm3)

Ws

weight of initially charged sulphur (g)

x

molar fraction of sulphur in sodium polysulphide (x in Na2Sx)

z

charge number

μ

local potential (V)

\(\bar \mu\)

equilibrium potential (V)

σ

electric conductivity (S cm−1)

ϕ

electric potential (V)

ϕ0

electronic potential at outer radius of sulphur electrode (V)

Subscripts

e

electronic conduction

i

ionic conduction

+

sodium ion, Na+

sulphur ion, S2−

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References

  1. [1]
    J. L. Sudworth and A. R. Tilley (eds), ‘The Sodium-Sulphur Battery’, Chapman and Hall, London (1985).Google Scholar
  2. [2]
    H. Kawamoto,J. Electrochem. Soc. 136 (1989) 1851.Google Scholar
  3. [3]
    J. Newman, ‘Electrochemical Systems’, Prentice-Hall, Englewood Cliffs NJ (1973).Google Scholar
  4. [4]
    K. D. South, J. L. Sudworth and J. G. Gibson,J. Electrochem. Soc. 119 (1972) 554.Google Scholar
  5. [5]
    B. Cleaver and A. J. Davies,Electrochim. Acta 18 (1973) 733.Google Scholar
  6. [6]
    B. Cleaver, A. J. Davies and M. D. Hames,18 (1973) 719.Google Scholar
  7. [7]
    S. D. Thompson and J. Newman,J. Electrochem. Soc. 136 (1989) 3362.Google Scholar
  8. [8]
    T. Risch and J. Newman,135 (1988) 1715.Google Scholar
  9. [9]
    H. Kawamoto,Denki Kagaku 58 (1990) 49.Google Scholar
  10. [10]
    H. Kawamoto and H. Hatoh,53 (1985) 366.Google Scholar
  11. [11]
    Y. K. Kao and P. C. Wayner, Jr.,J. Electrochem. Soc. 123 (1976) 230.Google Scholar
  12. [12]
    H. Kawamoto and M. Wada,134 (1987) 280.Google Scholar
  13. [13]
    M. Wada,134 (1987) 631.Google Scholar
  14. [14]
    M. C. H. McKubre, S. I. Smedley and F. L. Tanzella,136 (1989) 1962.Google Scholar
  15. [15]
    B. R. Karas,132 (1985) 1266.Google Scholar
  16. [16]
    J. G. Gibson,J. Appl. Electrochem. 4 (1974) 125.Google Scholar
  17. [17]
    General Electric Co.,EPRI Report EM-2579 (1982).Google Scholar
  18. [18]
    Idem General Electric Co.,ibid. EPRI Report EM-3453 (1984).Google Scholar
  19. [19]
    F. M. Stackpool, Proceedings of the Symposium on Sodium-Sulfur Batteries, A. R. Landgrebe, R. D. Weaver and R. K. Sen, Editors, The Electrochemical Society Softbound Proceedings Series, San Diego CA (1987) 183.Google Scholar
  20. [20]
    S. A. Naftel,J. Electrochem. Soc. 135 (1988) 26C.Google Scholar
  21. [21]
    S. Mennicke, in ‘Advances on Battery Materials and Processes’, (edited by J. McBreen, D-T. Chin, R. S. Yeo and A. C. C. Tesung). The Electrochemical Society Softbound Proceedings Series, Pennington NJ (1984) 85.Google Scholar
  22. [22]
    B. R. Karas,J. Electrochem. Soc. 132 (1985) 1261.Google Scholar
  23. [23]
    A. A. Koening, Proc. DOE/EPRI Beta (Sodium-Sulphur) Battery Workshop VI, EPRI Report AP-6012-SR (1988) 30.Google Scholar

Copyright information

© Chapman and Hall Ltd 1991

Authors and Affiliations

  • H. Kawamoto
    • 1
  1. 1.Advanced Reactor and Nuclear Fuel Cycle DepartmentHitachi Works, Hitachi, Ltd.Hitachi-shi, Ibaraki-ken 317Japan

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