EP0519985A1 - Sodium/sulphur cell - Google Patents
Sodium/sulphur cellInfo
- Publication number
- EP0519985A1 EP0519985A1 EP91906068A EP91906068A EP0519985A1 EP 0519985 A1 EP0519985 A1 EP 0519985A1 EP 91906068 A EP91906068 A EP 91906068A EP 91906068 A EP91906068 A EP 91906068A EP 0519985 A1 EP0519985 A1 EP 0519985A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cell
- sodium
- sulphur
- aluminium
- cathodic reaction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
- H01M10/39—Accumulators not provided for in groups H01M10/05-H01M10/34 working at high temperature
- H01M10/3909—Sodium-sulfur cells
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/02—Alloys based on aluminium with silicon as the next major constituent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/661—Metal or alloys, e.g. alloy coatings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- This invention relates to a sodium/sulphur cell.
- Both primary and secondary batteries of dry alkaline type are known, as are secondary batteries of lead acid type.
- a solid electrolyte - generally beta alumina - separates two liquid electrodes, namely liquid sulphur and liquid sodium electrodes.
- Such a sodium/sulphur cell is shown in the drawing which is a perspective view of the cell with part broken away.
- the cell comprises a case 1 of, for example steel, in the form of a right circular cylinder and containing a solid electrolyte cup 2 of beta alumina, the cup 2 containing a sodium electrode 3, while a space between the case 1 and the cup 2 contains a sulphur electrode 4.
- the cell is maintained at a temperature of between 300°C and 400°C such that the sodium and sulphur electrodes 3 and 4 are in liquid form.
- the open end of the cup 2 is closed by an insulating disc 5 of alpha alumina, while the case 1 is closed by an annular steel disc 6.
- the case 1 serves as a terminal for the sulphur electrode 4, while the sodium electrode 3 contains an elongate metal current collector 8 which extends axially of the case 1 out through the disc 5 where it is connected to a centre terminal disc 7 mounted on the disc 5, the necessary connections being made by welding.
- sulphur is essentially electronically non-conducting a means of providing electronic conduction to all parts of the sulphur electrode from the case 1 has to be provided, and this is generally achieved by forming the sulphur electrode 4 as a carbon fibre mat impregnated with the sulphur.
- beta alumina acts as a selective ion filter.
- sodium ions are transported through the beta alumina electrolyte cup 2 from the sodium electrode 3, to the sulphur electrode 4, and there combine with the sulphur to form some species of sodium polysulphide.
- the sodium polysulphide has to be transported away from the surface of the cup 2 and replaced with fresh sulphur.
- an inert material such as porcelain, enamel, or relatively inert molybdenum metal.
- the inert coating does not completely cover the additive material, an area of the surface thereof being left uncovered in dependence upon the required rate of release of the additive material into the cathodic reaction of the cell.
- a sodium/sulphur cell has a cathodic reaction region including a member of aluminium/silicon alloy.
- a particular advantage of the cell of the invention is that the aluminium/silicon alloy member does not require an inert coating to control the rate of corrosion thereof, since the use of silicon in the alloy reduces the rate of corrosion of the aluminium to an acceptable level due to the formation of a stable, tenacious, reaction product on the surface of the aluminium of the member.
- a preferred composition for the aluminium/silicon member is:- Aluminium 90 - 99.5%
- the aluminium/silicon alloy member can be provided in the form of a wire and will serve as an inactive electrical current carrying member in the cathodic reaction region of the cell, and may be connected to a current carrying member of the cell.
- aluminium/silicon alloy member can be provided as a coating on a wall or walls of the cathodic reaction region of the cell.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Secondary Cells (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
Une cellule au sodium/sulfure est caractérisée par une région de réaction cathodique, comprenant une partie en alliage aluminium/silicium.A sodium / sulfide cell is characterized by a cathodic reaction region, comprising an aluminum / silicon alloy portion.
Description
SODIUM/SULPHUR CELL
This invention relates to a sodium/sulphur cell.
Many forms of electrical batteries are known, and can be divided into two main types, mainly primary batteries which have a relatively short life and which are discarded when exhausted and secondary batteries which are rechargeable when exhausted and thus have a relatively long life.
Both primary and secondary batteries of dry alkaline type are known, as are secondary batteries of lead acid type.
Recently secondary batteries of sodium/sulphur type have become known, such batteries having the advantages of light weight, high storage capacity and relatively quick recharging time. Further, such batteries use sodium and sulphur both of which are cheap and abundant materials.
Unlike conventional lead acid batteries in which a liquid electrolyte - dilute sulphuric acid - separates two solid electrodes, in a sodium/sulphur cell a solid electrolyte - generally beta alumina - separates two liquid electrodes, namely liquid sulphur and liquid sodium electrodes.
Such a sodium/sulphur cell is shown in the drawing which is a perspective view of the cell with part broken away. As shown the cell comprises a case 1 of, for example steel, in the form of a right circular cylinder and containing a solid electrolyte cup 2 of beta alumina, the cup 2 containing a
sodium electrode 3, while a space between the case 1 and the cup 2 contains a sulphur electrode 4. For use, the cell is maintained at a temperature of between 300°C and 400°C such that the sodium and sulphur electrodes 3 and 4 are in liquid form.
The open end of the cup 2 is closed by an insulating disc 5 of alpha alumina, while the case 1 is closed by an annular steel disc 6.
The case 1 serves as a terminal for the sulphur electrode 4, while the sodium electrode 3 contains an elongate metal current collector 8 which extends axially of the case 1 out through the disc 5 where it is connected to a centre terminal disc 7 mounted on the disc 5, the necessary connections being made by welding.
As sulphur is essentially electronically non-conducting a means of providing electronic conduction to all parts of the sulphur electrode from the case 1 has to be provided, and this is generally achieved by forming the sulphur electrode 4 as a carbon fibre mat impregnated with the sulphur.
It will be appreciated that with such a cell the sodium and sulphur electrodes 3 and 4 can have their locations reversed.
The atomic structure of beta alumina is such that it acts as a selective ion filter.
As the cell is discharged sodium ions are transported through the beta alumina electrolyte cup 2 from the sodium
electrode 3, to the sulphur electrode 4, and there combine with the sulphur to form some species of sodium polysulphide. In order for discharge to continue, the sodium polysulphide has to be transported away from the surface of the cup 2 and replaced with fresh sulphur.
During recharging of the cell it has to be ensured that a continuous supply of sodium polysulphide is maintained at the surface of the cup 2. If sodium ions are removed from the sodium polysulphide at such a rate that fresh polysulphides cannot be taken to the surface of the cup 2 , a layer of sulphur will be formed at the surface, and this will cause the cell to suffer an increase in internal resistance, and its performance will be impaired.
To overcome this problem some form of preferential wetting at, and to, the surface of the cup 2 by sodium polysulphide has to be provided.
According to US-A-4767684 the problem discussed above, which is known as polarisation, can be overcome by including in the cathodic reaction region of the cell a device which provides a continuous release of an additive into the cathodic reaction. In particular this document proposes the use of a device comprising an additive material which is a metal from Groups, I, II and III of the Periodic Table of Elements; a Transition Series Metal; antimony, lead, tin or bismuth, or an alloy, salt, oxide, phosphide, arsenide, antimonide, carbide or nitride of any of the proposed metals.
or a mixture of any of these, contained in a coating of an inert material such as porcelain, enamel, or relatively inert molybdenum metal. The inert coating does not completely cover the additive material, an area of the surface thereof being left uncovered in dependence upon the required rate of release of the additive material into the cathodic reaction of the cell.
According to this invention a sodium/sulphur cell has a cathodic reaction region including a member of aluminium/silicon alloy.
It is believed that the inclusion of the aluminium/silicon alloy member in the cathodic reaction region of the cell results in corrosion products from the member being taken into solution and then redeposited on the material of the cathode so promoting preferential wetting thereof whereby the polarisation problem discussed above is overcome.
A particular advantage of the cell of the invention is that the aluminium/silicon alloy member does not require an inert coating to control the rate of corrosion thereof, since the use of silicon in the alloy reduces the rate of corrosion of the aluminium to an acceptable level due to the formation of a stable, tenacious, reaction product on the surface of the aluminium of the member. A preferred composition for the aluminium/silicon member is:-
Aluminium 90 - 99.5%
Silicon 0.2 - 10%
Magnesium 0 - 4%
Manganese 0 - 2%
Other Materials 0 - 2% The aluminium/silicon alloy member can be provided in the form of a wire and will serve as an inactive electrical current carrying member in the cathodic reaction region of the cell, and may be connected to a current carrying member of the cell.
Otherwise the aluminium/silicon alloy member can be provided as a coating on a wall or walls of the cathodic reaction region of the cell.
Tests have shown that cells in accordance with the invention show virtually no charge to discharge asymmetry, no polarisation problems, and a very low discharge resistance rise..
Claims
1. A sodium/sulphur cell having a cathodic reaction region including a member of aluminium/silicon alloy.
2. A cell as claimed in Claim 1, in which said member is provided in the cathodic reaction region in the form of a wire.
3. A cell as claimed in Claim 1, in which said member is provided as a coating on a wall or walls of the cathodic reaction region.
4. A cell as claimed in any preceding claim, in which said member is composed of:-
Aluminium 90 - 99.5%
Silicon 0.2 - 10%
Magnesium 0 - 4%
Manganese 0 - 2%
Other Materials 0 - 2%
5. A cell as claimed in any preceding claim, substantially as hereinbefore described with reference to the drawing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB909005803A GB9005803D0 (en) | 1990-03-15 | 1990-03-15 | Sodium/sulphur cell |
| GB9005803 | 1990-03-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0519985A1 true EP0519985A1 (en) | 1992-12-30 |
Family
ID=10672650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91906068A Withdrawn EP0519985A1 (en) | 1990-03-15 | 1991-03-08 | Sodium/sulphur cell |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0519985A1 (en) |
| JP (1) | JPH05505903A (en) |
| CA (1) | CA2077765A1 (en) |
| GB (1) | GB9005803D0 (en) |
| WO (1) | WO1991014293A2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3615239A1 (en) * | 1986-05-06 | 1987-11-12 | Bbc Brown Boveri & Cie | ELECTROCHEMICAL STORAGE CELL |
| JPH0793150B2 (en) * | 1986-08-29 | 1995-10-09 | 株式会社日立製作所 | Sodium-sulfur battery |
| US4767684A (en) * | 1987-08-19 | 1988-08-30 | Ford Motor Company | Method of chargeability improvement and reduced corrosion for sodium-sulfur cells |
-
1990
- 1990-03-15 GB GB909005803A patent/GB9005803D0/en active Pending
-
1991
- 1991-03-08 CA CA002077765A patent/CA2077765A1/en not_active Abandoned
- 1991-03-08 JP JP91505815A patent/JPH05505903A/en active Pending
- 1991-03-08 WO PCT/GB1991/000371 patent/WO1991014293A2/en not_active Ceased
- 1991-03-08 EP EP91906068A patent/EP0519985A1/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9114293A2 * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9005803D0 (en) | 1990-05-09 |
| WO1991014293A3 (en) | 1991-10-31 |
| JPH05505903A (en) | 1993-08-26 |
| CA2077765A1 (en) | 1991-09-16 |
| WO1991014293A2 (en) | 1991-09-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| 17P | Request for examination filed |
Effective date: 19920817 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE DE DK ES FR GB GR IT LU NL SE |
|
| 17Q | First examination report despatched |
Effective date: 19940113 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 19940525 |