CH511519A - Membranes suitable for use in the construction of electrochemical cells are prepared from sheets of asbestos, carbon, glass or polypropylene fibres bonded to get - Google Patents
Membranes suitable for use in the construction of electrochemical cells are prepared from sheets of asbestos, carbon, glass or polypropylene fibres bonded to getInfo
- Publication number
- CH511519A CH511519A CH844070A CH844070A CH511519A CH 511519 A CH511519 A CH 511519A CH 844070 A CH844070 A CH 844070A CH 844070 A CH844070 A CH 844070A CH 511519 A CH511519 A CH 511519A
- Authority
- CH
- Switzerland
- Prior art keywords
- asbestos
- prepared
- weight
- sheets
- glass
- Prior art date
Links
- 239000010425 asbestos Substances 0.000 title claims abstract description 29
- 229910052895 riebeckite Inorganic materials 0.000 title claims abstract description 29
- 239000012528 membrane Substances 0.000 title claims abstract description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title abstract 2
- 239000004743 Polypropylene Substances 0.000 title abstract 2
- 229910052799 carbon Inorganic materials 0.000 title abstract 2
- 238000010276 construction Methods 0.000 title abstract 2
- 239000011521 glass Substances 0.000 title abstract 2
- -1 polypropylene Polymers 0.000 title abstract 2
- 229920001155 polypropylene Polymers 0.000 title abstract 2
- 239000000835 fiber Substances 0.000 claims description 18
- 239000000446 fuel Substances 0.000 claims description 13
- 229920003023 plastic Polymers 0.000 claims description 11
- 239000004033 plastic Substances 0.000 claims description 11
- YACLQRRMGMJLJV-UHFFFAOYSA-N chloroprene Chemical compound ClC(=C)C=C YACLQRRMGMJLJV-UHFFFAOYSA-N 0.000 claims description 6
- 239000011230 binding agent Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 2
- 239000000853 adhesive Substances 0.000 abstract 1
- 230000001070 adhesive effect Effects 0.000 abstract 1
- 125000003277 amino group Chemical group 0.000 abstract 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 abstract 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract 1
- 239000003792 electrolyte Substances 0.000 description 11
- 239000007789 gas Substances 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
- B01D69/148—Organic/inorganic mixed matrix membranes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
- B01D69/1411—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing dispersed material in a continuous matrix
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B13/00—Diaphragms; Spacing elements
- C25B13/04—Diaphragms; Spacing elements characterised by the material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Fuel Cell (AREA)
Abstract
Membranes suitable for use in the construction of electrochemical cells are prepared from sheets of asbestos, carbon, glass or polypropylene fibres bonded together by a polymeric adhesive containing carboxyl, hydroxy, sulphonic or amine groups. - The membranes prepared are resistant to aqueous alkalis and of improved mechanical strength.
Description
Gasdichte Asbestmembran für Brennstoffelemente Die Erfindung betrifft eine gasdichte, hochreine As bestfasern und Kunststoff enthaltende Asbestmembran für Brennstoffelemente.
Es ist bereits bekannt, in Brennstoffelementen Asbest membranen als Diaphragmen zu verwenden. So sind bei spielsweise bei dem in der französischen Zusatzpatent schrift 87 850 beschriebenen Brennstoffelement Asbest diaphragmen zwischen ein den Elektrolyten enthaltendes Stützgerüst und den beidseitig angrenzenden Elektroden eingebaut, um dadurch die Gefahr eines Durchtritts der Reaktionsgase in den Elektrolyten zu verringern.
Es hat sich nun gezeigt, dass die handelsüblichen As bestmembranen den an Brennstoffelemente gestellten An forderungen nur unter bestimmten Betriebsbedingungen genügen. Unter dem Einfluss von alkalischen Elektrolyten quellen nämlich die Asbestfasern bzw. Asbestpapiere stark auf und es wird ein aus ungebundenen Fasern beste hendes Vlies gebildet, das beim Betrieb des Brennstoffele mentes beträchtliche Störungen verursachen kann.
Es ist bereits eine kunststoffhaltige Asbestmembran bekannt, die als Elektrolytträger in einem Brennstoffele ment benutzt werden soll. Diese Membran besteht aus ge reinigten Asbestfasern, denen wasserunlöslich gemachte Polyvinylalkoholfasern in Mengen von 2 bis 25 Gew.-%, bezogen auf das Gewicht der Membran, beigemischt sind. Durch einen Elektrolytträger aus diesem Material soll das an der Anode bei der elektrochemischen Umsetzung ge bildete Wasser leicht diffundieren können und dem sich zwischen Kathode und Anode ausbildenden Elektrolytkon zentrationsgefälle rasch entgegenwirken. Auch bei diesen bekannten Membranen besteht jedoch die Gefahr, dass sie insbesondere bei längerer Betriebsdauer des Brennstoff elementes und bei höheren Elektrolyttemperaturen nicht genügend beständig sind.
Durch Einwirkung des alkali schen oder sauren Elektrolyten des Brennstoffelementes können nämlich die zunächst wasserunlöslichen Polyvinyl- alkoholfasern in wasserlösliche Produkte umgewandelt werden bzw. sich im Elektrolyten auflösen. Die mechani sche Stabilität und Gasdichtigkeit der Membran ist dann nicht mehr gewährleistet.
Aufgabe der Erfindung ist es, eine hochreine Asbestfa- sern und Kunststoff enthaltende Asbestmembran für Brennstoffelemente so auszubilden, dass ihre mechanische Stabilität erhöht wird und sie vor allem auch noch nach längerer Betriebszeit gasdicht ist.
Dies wird erfindungsgemäss dadurch erreicht, dass der Kunststoff ein Bindemittel aus Chloropren in Mengen von 0,5 bis 6 Gew.-%, bezogen auf das Gewicht der Asbestfa sern, ist.
Vorzugsweise kann der Gewichtsanteil des Bindemit tels 1,5 bis 3 Gew.-%, bezogen auf das Gewicht der As bestfasern, betragen.
Der als Bindemittel dienende, gegenüber dem Elektro lyten beständige Kunststoff Chloropren wird bei dieser Membran den Asbestfasern in Form einer Dispersion bei gemischt.
Die gefundene Lösung ist vor allem deshalb überra schend, weil die bisher mit Kunststofflatices, insbesondere Gummilatices, vorbehandelten und hauptsächlich als Dich tungen eingesetzten Asbestpapiere, die einen wesentlich grösseren Kunststoffgehalt aufweisen, für den angegebe nen Verwendungszweck völlig ungeeignet sind. Derartige Asbestpapiere haben eine sehr geringe Volumenporosität und dichten deshalb zwar gegenüber den Reaktionsgasen gut ab, jedoch wird gleichzeitig damit der elektrische Widerstand untragbar hoch. Das Eindringen des Elektroly ten wird noch zusätzlich dadurch erschwert, dass die As bestpapiere einen relativ hohen Kunststoffgehalt aufwei sen (mind. 15 Gew.-%) und damit stark hydrophob sind.
Die neuen Asbestmembranen für Brennstoffelemente zeichnen sich vor allem dadurch aus, dass ihr elektrischer Widerstand sehr klein ist. So wurden an Asbestmembra nen, die 3 Gew.-% Chloropren enthalten und eine Dicke von 0,27 bis 0,65 mm haben, in 6 n KOH unterhalb 0,3 S2 - cm' liegende elektrische Widerstände gemessen. Dass bei einer derart grossen Volumenporosität noch eine gute und ausreichende Gasdichtigkeit erreicht wird - bei einer Druckbelastung von 2 atü erfolgt noch kein Gas durchtritt - war nicht zu erwarten.
Eine nennenswerte Quellung der Asbestfasermembranen konnte auch nach längerer Betriebsdauer bei Temperaturen bis zu 60 C und Verwendung von 6 n KOH nicht beobachtet werden. Die Herstellung der Asbestmembranen erfolgt in an sich bekannter Weise durch Aufziehen von wässrigen Dis persionen von Chloropren. Diese werden von wässrigen Alkalilösungen nicht angegriffen und zeigen gegenüber Luft bzw. Sauerstoff eine gute Stabilität.
Um gasdichte Membranen mit guten mechanischen Eigenschaften zu erhalten, werden hochreine Asbestfasern als Ausgangsmaterial eingesetzt, die frei von Verunreini gungen und nicht aufgeschlossenen Faserbündeln sind. Die Reinigung erfolgt am besten in an sich bekannter Weise durch Aufschlämmen in Wasser, wobei es vorteil haft ist, oberflächenaktive Mittel zuzusetzen. Nach Abde kantieren und Trocknen der Asbestfasern können noch anhaftende Verunreinigungen im Windsichter entfernt werden. Die in destilliertem Wasser aufgeschlämmten As bestfasern werden anschliessend unter kräftigem Rühren mit 0,5 bis 6 Gew.-% einer Chloroprendispersion, bezogen auf das Gewicht des Feststoffgehaltes der Dispersion, ver setzt und in einer geeigneten Vorrichtung, beispielsweise in einem Blattbildner, weiterverarbeitet. Nach Trocknung bei 80 C und Verdichten, z.
B. im Kalander oder Pressen bei dem verwendeten Kunststoff angepassten Temperatu ren, können die hergestellten gasdichten Membranen so fort in Brennstoffelementen eingesetzt werden.
Gas-tight asbestos membrane for fuel elements The invention relates to a gas-tight, highly pure asbestos fibers and plastic containing asbestos membrane for fuel elements.
It is already known to use asbestos membranes as diaphragms in fuel elements. For example, asbestos diaphragms are installed between a support structure containing the electrolyte and the two-sided adjacent electrodes in the fuel element described in the French additional patent writing 87 850, thereby reducing the risk of the reaction gases penetrating the electrolyte.
It has now been shown that the commercially available As best membranes meet the requirements placed on fuel elements only under certain operating conditions. Under the influence of alkaline electrolytes, the asbestos fibers or asbestos papers swell to a great extent and a non-woven fabric consisting of unbound fibers is formed, which can cause considerable malfunctions when the fuel element is in operation.
There is already a plastic-containing asbestos membrane known to be used as an electrolyte carrier in a fuel element. This membrane consists of purified asbestos fibers to which water-insoluble polyvinyl alcohol fibers are added in amounts of 2 to 25% by weight, based on the weight of the membrane. By means of an electrolyte carrier made of this material, the water formed at the anode during the electrochemical conversion should be able to easily diffuse and quickly counteract the gradient in the concentration of electrolytes that forms between the cathode and anode. Even with these known membranes, however, there is the risk that they will not be sufficiently stable, especially if the fuel element is in operation for a long time and at higher electrolyte temperatures.
The effect of the alkali or acidic electrolyte of the fuel element can namely convert the initially water-insoluble polyvinyl alcohol fibers into water-soluble products or dissolve in the electrolyte. The mechanical stability and gas tightness of the membrane is then no longer guaranteed.
The object of the invention is to design an asbestos membrane containing high-purity asbestos fibers and plastic for fuel elements in such a way that its mechanical stability is increased and, above all, it is gas-tight even after a long period of operation.
This is achieved according to the invention in that the plastic is a binder made of chloroprene in amounts of 0.5 to 6% by weight, based on the weight of the asbestos fibers.
The proportion by weight of the binder can preferably be 1.5 to 3% by weight, based on the weight of the As best fibers.
The plastic chloroprene, which is used as a binder and is resistant to the electrolyte, is mixed with the asbestos fibers in this membrane in the form of a dispersion.
The solution found is above all surprising because the asbestos papers that have been pretreated with plastic latices, in particular rubber latices and are mainly used as seals, which have a much larger plastic content, are completely unsuitable for the intended use. Asbestos papers of this type have a very low volume porosity and therefore seal off well against the reaction gases, but at the same time the electrical resistance becomes unacceptably high. Penetration of the electrolyte is made even more difficult by the fact that the asbestos papers have a relatively high plastic content (at least 15% by weight) and are therefore highly hydrophobic.
The new asbestos membranes for fuel elements are mainly characterized by the fact that their electrical resistance is very low. For example, asbestos membranes containing 3% by weight of chloroprene and having a thickness of 0.27 to 0.65 mm were measured in 6N KOH below 0.3 S2 - cm 'electrical resistances. It was not to be expected that with such a large volume porosity a good and sufficient gas tightness would still be achieved - with a pressure load of 2 atmospheres no gas would penetrate.
Significant swelling of the asbestos fiber membranes could not be observed even after a long period of operation at temperatures of up to 60 ° C. and the use of 6N KOH. The asbestos membranes are produced in a manner known per se by drawing up aqueous dispersions of chloroprene. These are not attacked by aqueous alkali solutions and show good stability towards air or oxygen.
In order to obtain gas-tight membranes with good mechanical properties, high-purity asbestos fibers are used as the starting material, which are free of impurities and undigested fiber bundles. The cleaning is best carried out in a manner known per se by slurrying in water, it being advantageous to add surface-active agents. After the asbestos fibers have been canted and dried, any remaining impurities can be removed in the wind sifter. The As best fibers suspended in distilled water are then added with vigorous stirring with 0.5 to 6% by weight of a chloroprene dispersion, based on the weight of the solids content of the dispersion, and processed further in a suitable device, for example in a sheet former. After drying at 80 C and compressing, e.g.
B. in the calender or pressing with the plastic used adapted Temperatu ren, the gas-tight membranes produced can be used immediately in fuel elements.
Claims (1)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES0107252 | 1966-12-03 | ||
DES0111724 | 1967-09-08 | ||
CH1449267A CH510333A (en) | 1966-12-03 | 1967-10-16 | Gas-tight membrane for electrochemical cells |
Publications (1)
Publication Number | Publication Date |
---|---|
CH511519A true CH511519A (en) | 1971-08-15 |
Family
ID=27177182
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH844070A CH511519A (en) | 1966-12-03 | 1967-10-16 | Membranes suitable for use in the construction of electrochemical cells are prepared from sheets of asbestos, carbon, glass or polypropylene fibres bonded to get |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH511519A (en) |
-
1967
- 1967-10-16 CH CH844070A patent/CH511519A/en not_active IP Right Cessation
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PL | Patent ceased |