Electric accumulator with a solid electrolyte

Abstract

Electric accumulators of the type comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal, in the form of cations are improved by adding to the anode compartment a salt of the anode metal between the anode and the separation wall.

I claim: .[.1. In an electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator, said electrolyte being maintained in a molten state; the anode compartment and cathode compartment being separated from each other by wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations; the improvement consisting in that the anode compartment contains a porous matrix adjacent said anode and at least one salt of the anode metal capable of allowing migration of this metal in the form of cations, said salt being maintained in a molten state and permeating said porous matrix, with said salt and said matrix being interposed between the anode and said separation wall..]. .[.2. The accumulator of claim 1, wherein said anode metal salt 
     
        has a melting point not exceeding about 200° C..]. 3. .[.The accumulator of claim 1,.]. .Iadd.An electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator, said electrolyte being maintained in a molten state; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations; wherein the anode compartment contains a porous matrix adjacent said anode and at least one salt of the anode metal capable of allowing migration of this metal in the form of cations, said salt being maintained in a molten state and permeating said porous matrix, with said salt and said matrix being interposed between the anode and said separation wall, and .Iaddend.wherein said anode metal salt is selected from the group consisting of compounds of the two general formulas:   Me(BR.sub.4).sub.n and Me(AlR.sub.4).sub.n     (in which Me represents a metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements, R represents an alkyl or aryl group and n is 1, 2 or 3, according to the valency of the metal Me) and mixtures of at least two of   
     
     
        these compounds. 4. The accumulator of claim 3, wherein said anode metal 
     
     
        salt is sodium tetraethylaluminate NaAl(C 2  H 5 ) 4 . 5. .[.The accumulator of claim 1,.]. .Iadd.An electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator, said electrolyte being maintained in a molten state; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations; wherein the anode compartment contains a porous matrix adjacent said anode and at least one salt of the anode metal capable of allowing migration of this metal in the form of cations, said salt being maintained in a molten state and permeating said porous matrix, with said salt and said matrix being interposed between the anode and said separation wall, and .Iaddend.wherein said anode metal salt is chosen from the group consisting of compounds of the two general formulas:   Me(BR.sub.3 H).sub.n and .[.MeAl(R.sub.3 H).sub.n 173 .Iadd.Me(AlR.sub.3).sub.n .Iaddend.     (in which Me represents a metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements, R represents an alkyl or aryl group and n is 1, 2 or 3 according to the valency of the metal Me) and mixtures of at least two of these   
     
     
        compounds. 6. The accumulator of claim 5, wherein said anode metal salt is the compound of formula NaB(C 2  H 5 ) 3  H.  .[.7. The accumulator of claim 1, wherein said anode metal is sodium..]. .[.8. The accumulator of claim 1, wherein said solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations is sodium beta aluminate..]. .[.9. The accumulator of claim 1, wherein said substance contained in the cathode compartment and capable of dissolving the products generated during accumulator discharge consists of at least one anode metal salt selected from the same group as the anode metal 
     
     
        contained in the anode compartment..]. 10. .[.The accumulator of claim 1,.]. .Iadd.An electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator, said electrolyte being maintained in a molten state; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations; wherein the anode compartment contains a porous matrix adjacent said anode and at least one salt of the anode metal capable of allowing migration of this metal in the form of cations, said salt being maintained in a molten state and permeating said porous matrix, with said salt and said matrix being interposed between the anode and said separation wall, and .Iaddend.wherein said substance contained in the cathode compartment and capable of dissolving the products generated during accumulator discharge consists of a metal halogenoaluminate of formula MeAlX 4 , wherein Me is a metal selected from the group consisting of metals belonging to 
     
     
        Groups Ia, IIa, IIb and IIIb of the periodic table of elements. 11. The accumulator of claim 10, wherein the said substance is the eutectic 
     
     
        mixture NaCl-AlCl 3 . 12. .[.The accumulator of claim 1,.]. .Iadd.An electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a conducting member comprising a substance capable of accepting electrons, to form anions by cathodic reduction, and an electrolyte consisting of a substance capable of dissolving the product or products generated during discharge of the accumulator, said electrolyte being maintained in a molten state; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from a solid mineral electrolyte capable of allowing selective migration of the anode metal in the form of cations; wherein the anode compartment contains a porous matrix adjacent said anode and at least one salt of the anode metal capable of allowing migration of this metal in the form of cations, said salt being maintained in a molten state and permeating said porous matrix, with said salt and said matrix being interposed between the anode and said separation wall, and .Iaddend.wherein said substance capable of accepting electrons to form 
     
     
        anions by cathodic reduction is a transition metal salt. 13. The accumulator of claim 12, wherein said transition metal salt is selected 
     
     
        from the group consisting of halides, oxides and sulphides. 14. The accumulator of claim 12, wherein said transition metal is selected from 
     
     
        the group consisting of iron, nickel cobalt, chromium and vanadium. 15. The accumulator of claim 12, wherein said transition metal salt is 
     
     
        ferrous chloride FeCl 2 . 16. In an electric accumulator comprising an anode compartment containing an anode formed from at least one metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIb of the periodic table of elements; a cathode compartment containing a cathode formed at least partly from a transition metal, and an electrolyte which is maintained in a molten state; the anode compartment and cathode compartment being separated from each other by a wall impervious to fluids and formed from sodium beta aluminate; the improvement consisting in that the anode compartment contains a porous matrix adjacent said anode and at least one anode metal salt having a melting point not exceeding about 200° C. and being selected from the group consisting of compounds of the general formulas: Me(BR 4 ) n , Me(AlR 4 ) n , Me(BR 3  H) n , Me(AlR 3  H) n  and MeAlX 4  (in which Me represents a metal selected from the group consisting of metals belonging to Groups Ia, IIa, IIb and IIIB of the periodic table of elements, R represents an alkyl or aryl group and n is 1, 2 or 3, according to the valency of the metal Me and X is a halogen atoms) and mixtures of at least two of these compounds, said salt being maintained in a molten state and permeating said porous matrix; the electrolyte being selected from the group consisting of the same group as the anode metal salt and the eutectic mixture NaCl-AlCl 3 .