CA1149451A - Predischarged nonaqueous cell - Google Patents
Predischarged nonaqueous cellInfo
- Publication number
- CA1149451A CA1149451A CA000363721A CA363721A CA1149451A CA 1149451 A CA1149451 A CA 1149451A CA 000363721 A CA000363721 A CA 000363721A CA 363721 A CA363721 A CA 363721A CA 1149451 A CA1149451 A CA 1149451A
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- Prior art keywords
- cell
- additive
- cathode
- beta
- mno2
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- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
-
- 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
- H01M4/06—Electrodes for primary cells
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/502—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese for non-aqueous cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/14—Cells with non-aqueous electrolyte
- H01M6/16—Cells with non-aqueous electrolyte with organic electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/50—Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/14—Cells with non-aqueous electrolyte
- H01M6/16—Cells with non-aqueous electrolyte with organic electrolyte
- H01M6/162—Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte
- H01M6/168—Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte by additives
-
- 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
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49108—Electric battery cell making
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Primary Cells (AREA)
Abstract
PREDISCHARGED NONAQUEOUS CELL
ABSTRACT
An electrochemical cell containing a decomposing electrolyte solvent, further contains small amounts of an additive material such as lithium sulfide which causes partial self discharge of the cathode of the cell with non-reactive products. The self discharge partially deactivates substantially all of the active cathode surface as a reaction site thereby reducing the decomposition of the electrolyte solvent.
ABSTRACT
An electrochemical cell containing a decomposing electrolyte solvent, further contains small amounts of an additive material such as lithium sulfide which causes partial self discharge of the cathode of the cell with non-reactive products. The self discharge partially deactivates substantially all of the active cathode surface as a reaction site thereby reducing the decomposition of the electrolyte solvent.
Description
~1~94Sl This inYention relate~ to non-a~ueous electrolyte cells, particularly those cont~ining decomposing electrolyte so~Yents and ~ore particularly those also containing beta-man~anese dio~i~de cathodes.
Non-aqueous electrolyte cells generally require the stringent exclu-sion of water which is usually accomplished by rigorous heating and drying procedures. Such procedures are required since it is believed that retained water detrimentally reacts with the active ~etal (metals above hydrogen in the EMF series) anodes, such as lithium, used in such cells with resultant gas evolution. The problem of retained water is particularly exacerbated in cells containing cathodes such as metal oxides which are generally hygro-scopic in nature and tenaciously retain absorbed or adsorbed water. Thus, for example, manganese dioxide utilized in the substantially beta form as the acti~e cathode material in non-aqueous cells requires rigorous heat treatment (20aC or higher when formed into cathodes with binders) to drive off retained water (see U.S. Patent No. 4,133,856). Without such heat treat-ment such cells are dimensionally unstable and have reduced electrochemical capabilities. In U.S. Patent No. 4,279,972 I disclosed that in small amounts, water retained in a cell, particularly in a cathode, does not in fact detrimentally react with the active metal anode but rather initiates a reac-tion between certain commonly used electrolyte salts and solvents.
This reaction leads to decomposition of the solvents such as propylene car-bonate with resultant evolution of gaseous reaction products (presumably C02 in the case of propylene carbonate) which detrimentally affect cell stability and capacity. In U.S. Patent No. 4,264,689 I disclosed that such reaction could be minimized with lesser heating or even without heating by partially deactivating substantially all of the active cathode surfsce.
~9451 Without a site for the reaction of electrolyte salt and solvent the decom-position of the solvent is thereby minimized with resultant increased cell stability. In order to provide such deactivation it was specifically dis-closed that an additive such as LiNO3, particularly when mixed with the cathode active materials prior to formation of the cathode, would thereafter react with active surface members on the cathode and reduce them to less active states. The cathode as deactivated would then be assembled into a cell.
It is an object of the present invention to provide additives for use within an electrochemical cell which partially deactivate substantially all of the active cathode surface after the cell is assembled and prior to initial cell discharge.
It is a further object of the present invention to provide an electrochemical cell having additives therein which self discharge the cathode thereof to a limited extent to partially deactivate substantially all of the active cathode surface.
It is a still further object of the present invention to provide a nonaqueous cell which does not require rigorous heat treatment to drive off retained water therefrom.
These and other objects, features and advantages will become more evident from the following discussion.
Generally the present invention comprises the inclusion of an additive within an electrochemical cell which self discharges the cathode to a limited extent whereby partial deactivation of substantially all of the ~ctive cathode surface takes place. With such self discharge and deactivation, decomposable electrolyte solvents such as propylene carbonate are substan-tially prevented from such decomposition even in the presence of small amounts of water and detrimental gaseous evolution is likewise minimized. Rigorous heat treatment of the cathode is therefore obviated. Elimination or reduction of the cathode heat treatment step provides an additional benefit whereby tarnishing of the cell containers, made of stainless steel, caused by such heating step is likewise reduced. With the reduction of tarnishing and though stainless steel provides greater mechanical strength, the use of aluminum for containers is preferred because of greater conductivity, lower cost and lightness.
The additives of the present invention, in order to provide the requisite deactivation of substantially all of the active cathode surface, must be in intimate contact with such surface. In order to provide such intimate contact it is generally necessary that the additive be at least partially soluble in the electrolyte solvent. It is a further criterion of the additive that reaction products or products of the chemically induced cathode self discharge be substantially unreactive within the cell whereby once the cathode surface is deactivated thereby with consumption of the additive, further reaction does not continue thereby unnecessarily reducing cell capacity. In order to provide the requisite cathode self discharge but without unduly reducing cell capacity it is preferred that the amount of the additive be of a magnitude whereby no more than 5% of the capacity of the cathode is discharged thereby. ~hen the additive has a partial but low solubility in the electrolyte solvent it is preferred that the additive be introduced within the cell as an admixture with the active cathode mater-ial. The partial solubility of the additive thereafter provides full cathode surface contact via the fluid electrolyte solution when the cell is assembled. Alternatively, with more soluble additives, they may be intro-duced into the cell as a solvated species in the electrolyte solvent.
~-3515 An example of a particularly effective additive even when used in small amounts is lithium sulfide. Other additives include alkali and alkali earth metal sufides, selenides, tellurides such as Na2S, K~S, MgS, CaS, Li2Se, Na2Se, K2Se, MgSe, CaSe, Li2Te, Na2Te, K2Te, MgTe, and CaTe and generally inorganic or organic materials which fulfill the criteria of a) reaction with the active cathode surface to discharge said surface, b) at least partial solubility in the electrolyte solvent whereby intimate contact with the active cathode surface is possible and c) reaction products with the cathode which are substantially unreactive in the cell whereby the discharge reaction ceases once the additive is consumed.
The additives of the present invention are of particular utility in cells having active metal anodes such as lithium, sodium, potassium, magnesium, calcium and aluminum as anodes since such active metals are generally utili~ed in cells containing nonaqueous electrolytes which are particularly susceptible to decomposition and gaseous evolution.
Examples of active cathode materials which are particularly sus-ceptible to water retention include metal oxides such as the aforementioned beta manganese dioxide, TiO2, SnO2,MoO3, V2O5, CrO3, PbO, Fe2O3 and gen-erally transition metal oxides. Though metal oxides have been enumerated as cathode materlals, the present invention is equally applicable to cells containing other cathode materials in which water retention and solvent de-composition present problems.
Nonaqueous electrolyte solvents which are sub~ect to decomposition with gaseous evolution include propylene carbonate and dimethoxyethane, (PC and DME~ (commonly used as solvents in cells containing beta-manganese dioxide cathodes) and dimethyl sulfoxide.
~1-3515 9~51 In order to more fully illustrate the efficacy of the present invention the following examples are presented. Since the examples are for illustrative purposes details therein should not be construed as limitations on the present invention. Unless otherwise indicated all parts are parts by weight.
EXAMPLE 1 (PRIOR ART) Nine hundred milligrams of gamma-electrolytic manganese dioxide (EMD) are heated to 375C for three hours, The gamma-EMD is converted to beta-MnO2 which is then mixed with 60 milligrams of graphite, as conductive diluent, and 40 milligrams of a polytetrafluoroethylene (PTFE) dispersion, as binder. The mixture is formed into a pellet (about 1" (2.54 cm) diameter) and heated to 300C under a vacuum for 6 hours. The cathode pellet is then assembled into a flat wafer cell (0.100" (.254 cm) height by 1" (2.54 cm) diameter) with a lithium foil disc (700 mg) anode, a non-woven polypropylene separator and an electrolyte solution of about 275 mg lM LiC104 in an equi-volume mixture of PC/DME. The completed cell is heated to 115C for one hour and cooled to room temperature with an expansion of about 0.005 inch (0.0127 cm).
A second cell made in an identical manner provides an average open circuit voltage (OCV) of about 3.60 volts over a period of 2 months when stored at room temperature. The capacity of a similar cell stored at 50C
for 60 days when discharged at lmA is about 218 mAhr.
~l-3515 11'~9451 EXAMPLE 2 (MODIFIED PRIOR ART) A cell is made in accordance with the procedure in Example 1 but after the cathode pellet is formed it is heated to 150C for 6 hours rather than 300C. The cell is heated to 115C for one hour and cooled to room temperature with an expansion of about 0.030 inches (0.0762 cm).
A cell is made as in Example 2 but with 0.5% ~25 mg) Li2S mixed into the cathode before the pelletizing step. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.005 inch (0.0127 cm). A second cell made in an identical manner provides an average OCV of about 3.32 volts over a period of 2 months when stored at room temperature. The capacity of a similar cell stored at 50C
for 60 days is about 215 mAhr when discharged at lmA.
A cell is made in accordance with Example 3 but with 1% (r~lOmg) Li2S in the cathode. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.003 inch (0.00762 cm). A second cell made in an identical manner provides an average OCV of about 3.10 volts over a period of 2 months when stored at room tem-perature. The capacity of a similar cell (stored for 60 days at 50C) is about 212 mAhr when discharged at lmA.
A cell is made as in Example 3 but with 2%(~20 mg) of Li2S in the cathode. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.003 inch (0.00762 cm).
The capacity of a similar cell (stored for 60 days at 50C) is about 200 mAhr when discharged at ~mA.
` 1~49451 Four cells are made as in Example 1 but with heat treatment of the pelletized cathode being at 25, 150, 225 and 300C respectively. Four additional cells are made as in Example 3 but with the heat treatment of the pelletized cathode being at 25, 150, 225 and 300C respectively. All the cells are thereafter heated to 115C for one hour and cooled to room temperature.
The expansion of the cells under the cited conditions is summarized in the following table.
TABLE
Cell andPellet Treatment% Li S in% Cell Expansion (Heated Example #Temperature (C)Cathodeto 115C 1 hr-cooled room temp.) 6 25 0.0 37 7 150 0.0 33 8 225 0.0 25 9 300 0.0 6 0.5 17 11 150 0.5 4 12 225 0.5 3 13 300 0.5 3 ~i~9451 From the above examples it is clearly evident th~t by the addition of small amounts of the additives of the present invention cell stability is enhanced without the necessity for costly heating. The minimally lowered energy density caused by the additive in fact may be beneficial since as indi-cated in Examples 3 and 4the OCV is lowered and to which the loss in energy density may be attributed. The high OCV (about 3.6 volts) and high initial voltages may be detrimental to electrical equipment presently adapted to be operable at the standard alkaline cell voltage of about 3 volts (2 cells in series). The additives of the present invention therefore provide a means whereby the high initial voltages of the cells may be reduced or suppressed which enables such cells to be used in existing equipment initially adapted to the lower voltages.
It is understood that the above examples are for illustrative pur-poses and enumeration of specific details contained therein should not be construed as limitations on the present invention as defined in the following claims.
Non-aqueous electrolyte cells generally require the stringent exclu-sion of water which is usually accomplished by rigorous heating and drying procedures. Such procedures are required since it is believed that retained water detrimentally reacts with the active ~etal (metals above hydrogen in the EMF series) anodes, such as lithium, used in such cells with resultant gas evolution. The problem of retained water is particularly exacerbated in cells containing cathodes such as metal oxides which are generally hygro-scopic in nature and tenaciously retain absorbed or adsorbed water. Thus, for example, manganese dioxide utilized in the substantially beta form as the acti~e cathode material in non-aqueous cells requires rigorous heat treatment (20aC or higher when formed into cathodes with binders) to drive off retained water (see U.S. Patent No. 4,133,856). Without such heat treat-ment such cells are dimensionally unstable and have reduced electrochemical capabilities. In U.S. Patent No. 4,279,972 I disclosed that in small amounts, water retained in a cell, particularly in a cathode, does not in fact detrimentally react with the active metal anode but rather initiates a reac-tion between certain commonly used electrolyte salts and solvents.
This reaction leads to decomposition of the solvents such as propylene car-bonate with resultant evolution of gaseous reaction products (presumably C02 in the case of propylene carbonate) which detrimentally affect cell stability and capacity. In U.S. Patent No. 4,264,689 I disclosed that such reaction could be minimized with lesser heating or even without heating by partially deactivating substantially all of the active cathode surfsce.
~9451 Without a site for the reaction of electrolyte salt and solvent the decom-position of the solvent is thereby minimized with resultant increased cell stability. In order to provide such deactivation it was specifically dis-closed that an additive such as LiNO3, particularly when mixed with the cathode active materials prior to formation of the cathode, would thereafter react with active surface members on the cathode and reduce them to less active states. The cathode as deactivated would then be assembled into a cell.
It is an object of the present invention to provide additives for use within an electrochemical cell which partially deactivate substantially all of the active cathode surface after the cell is assembled and prior to initial cell discharge.
It is a further object of the present invention to provide an electrochemical cell having additives therein which self discharge the cathode thereof to a limited extent to partially deactivate substantially all of the active cathode surface.
It is a still further object of the present invention to provide a nonaqueous cell which does not require rigorous heat treatment to drive off retained water therefrom.
These and other objects, features and advantages will become more evident from the following discussion.
Generally the present invention comprises the inclusion of an additive within an electrochemical cell which self discharges the cathode to a limited extent whereby partial deactivation of substantially all of the ~ctive cathode surface takes place. With such self discharge and deactivation, decomposable electrolyte solvents such as propylene carbonate are substan-tially prevented from such decomposition even in the presence of small amounts of water and detrimental gaseous evolution is likewise minimized. Rigorous heat treatment of the cathode is therefore obviated. Elimination or reduction of the cathode heat treatment step provides an additional benefit whereby tarnishing of the cell containers, made of stainless steel, caused by such heating step is likewise reduced. With the reduction of tarnishing and though stainless steel provides greater mechanical strength, the use of aluminum for containers is preferred because of greater conductivity, lower cost and lightness.
The additives of the present invention, in order to provide the requisite deactivation of substantially all of the active cathode surface, must be in intimate contact with such surface. In order to provide such intimate contact it is generally necessary that the additive be at least partially soluble in the electrolyte solvent. It is a further criterion of the additive that reaction products or products of the chemically induced cathode self discharge be substantially unreactive within the cell whereby once the cathode surface is deactivated thereby with consumption of the additive, further reaction does not continue thereby unnecessarily reducing cell capacity. In order to provide the requisite cathode self discharge but without unduly reducing cell capacity it is preferred that the amount of the additive be of a magnitude whereby no more than 5% of the capacity of the cathode is discharged thereby. ~hen the additive has a partial but low solubility in the electrolyte solvent it is preferred that the additive be introduced within the cell as an admixture with the active cathode mater-ial. The partial solubility of the additive thereafter provides full cathode surface contact via the fluid electrolyte solution when the cell is assembled. Alternatively, with more soluble additives, they may be intro-duced into the cell as a solvated species in the electrolyte solvent.
~-3515 An example of a particularly effective additive even when used in small amounts is lithium sulfide. Other additives include alkali and alkali earth metal sufides, selenides, tellurides such as Na2S, K~S, MgS, CaS, Li2Se, Na2Se, K2Se, MgSe, CaSe, Li2Te, Na2Te, K2Te, MgTe, and CaTe and generally inorganic or organic materials which fulfill the criteria of a) reaction with the active cathode surface to discharge said surface, b) at least partial solubility in the electrolyte solvent whereby intimate contact with the active cathode surface is possible and c) reaction products with the cathode which are substantially unreactive in the cell whereby the discharge reaction ceases once the additive is consumed.
The additives of the present invention are of particular utility in cells having active metal anodes such as lithium, sodium, potassium, magnesium, calcium and aluminum as anodes since such active metals are generally utili~ed in cells containing nonaqueous electrolytes which are particularly susceptible to decomposition and gaseous evolution.
Examples of active cathode materials which are particularly sus-ceptible to water retention include metal oxides such as the aforementioned beta manganese dioxide, TiO2, SnO2,MoO3, V2O5, CrO3, PbO, Fe2O3 and gen-erally transition metal oxides. Though metal oxides have been enumerated as cathode materlals, the present invention is equally applicable to cells containing other cathode materials in which water retention and solvent de-composition present problems.
Nonaqueous electrolyte solvents which are sub~ect to decomposition with gaseous evolution include propylene carbonate and dimethoxyethane, (PC and DME~ (commonly used as solvents in cells containing beta-manganese dioxide cathodes) and dimethyl sulfoxide.
~1-3515 9~51 In order to more fully illustrate the efficacy of the present invention the following examples are presented. Since the examples are for illustrative purposes details therein should not be construed as limitations on the present invention. Unless otherwise indicated all parts are parts by weight.
EXAMPLE 1 (PRIOR ART) Nine hundred milligrams of gamma-electrolytic manganese dioxide (EMD) are heated to 375C for three hours, The gamma-EMD is converted to beta-MnO2 which is then mixed with 60 milligrams of graphite, as conductive diluent, and 40 milligrams of a polytetrafluoroethylene (PTFE) dispersion, as binder. The mixture is formed into a pellet (about 1" (2.54 cm) diameter) and heated to 300C under a vacuum for 6 hours. The cathode pellet is then assembled into a flat wafer cell (0.100" (.254 cm) height by 1" (2.54 cm) diameter) with a lithium foil disc (700 mg) anode, a non-woven polypropylene separator and an electrolyte solution of about 275 mg lM LiC104 in an equi-volume mixture of PC/DME. The completed cell is heated to 115C for one hour and cooled to room temperature with an expansion of about 0.005 inch (0.0127 cm).
A second cell made in an identical manner provides an average open circuit voltage (OCV) of about 3.60 volts over a period of 2 months when stored at room temperature. The capacity of a similar cell stored at 50C
for 60 days when discharged at lmA is about 218 mAhr.
~l-3515 11'~9451 EXAMPLE 2 (MODIFIED PRIOR ART) A cell is made in accordance with the procedure in Example 1 but after the cathode pellet is formed it is heated to 150C for 6 hours rather than 300C. The cell is heated to 115C for one hour and cooled to room temperature with an expansion of about 0.030 inches (0.0762 cm).
A cell is made as in Example 2 but with 0.5% ~25 mg) Li2S mixed into the cathode before the pelletizing step. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.005 inch (0.0127 cm). A second cell made in an identical manner provides an average OCV of about 3.32 volts over a period of 2 months when stored at room temperature. The capacity of a similar cell stored at 50C
for 60 days is about 215 mAhr when discharged at lmA.
A cell is made in accordance with Example 3 but with 1% (r~lOmg) Li2S in the cathode. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.003 inch (0.00762 cm). A second cell made in an identical manner provides an average OCV of about 3.10 volts over a period of 2 months when stored at room tem-perature. The capacity of a similar cell (stored for 60 days at 50C) is about 212 mAhr when discharged at lmA.
A cell is made as in Example 3 but with 2%(~20 mg) of Li2S in the cathode. The completed cell is heated to 115C for one hour and then cooled to room temperature with an expansion of about 0.003 inch (0.00762 cm).
The capacity of a similar cell (stored for 60 days at 50C) is about 200 mAhr when discharged at ~mA.
` 1~49451 Four cells are made as in Example 1 but with heat treatment of the pelletized cathode being at 25, 150, 225 and 300C respectively. Four additional cells are made as in Example 3 but with the heat treatment of the pelletized cathode being at 25, 150, 225 and 300C respectively. All the cells are thereafter heated to 115C for one hour and cooled to room temperature.
The expansion of the cells under the cited conditions is summarized in the following table.
TABLE
Cell andPellet Treatment% Li S in% Cell Expansion (Heated Example #Temperature (C)Cathodeto 115C 1 hr-cooled room temp.) 6 25 0.0 37 7 150 0.0 33 8 225 0.0 25 9 300 0.0 6 0.5 17 11 150 0.5 4 12 225 0.5 3 13 300 0.5 3 ~i~9451 From the above examples it is clearly evident th~t by the addition of small amounts of the additives of the present invention cell stability is enhanced without the necessity for costly heating. The minimally lowered energy density caused by the additive in fact may be beneficial since as indi-cated in Examples 3 and 4the OCV is lowered and to which the loss in energy density may be attributed. The high OCV (about 3.6 volts) and high initial voltages may be detrimental to electrical equipment presently adapted to be operable at the standard alkaline cell voltage of about 3 volts (2 cells in series). The additives of the present invention therefore provide a means whereby the high initial voltages of the cells may be reduced or suppressed which enables such cells to be used in existing equipment initially adapted to the lower voltages.
It is understood that the above examples are for illustrative pur-poses and enumeration of specific details contained therein should not be construed as limitations on the present invention as defined in the following claims.
Claims (10)
1. A method of stabilizing an electrochemical cell having an active metal anode, a solid active cathode and a non-aqueous electrolyte, said method comprising the step of placing a cathode discharging additive within said cell, said additive being at least partially soluble in said electrolyte and in sufficient quantity to self discharge substantially all of the surface of said active cathode prior to initial discharge of said cell and wherein reaction products of said self discharge are substantially non-reactive within said cell.
2. The method of claim 1 wherein said additive is placed within said cell by mixing said additive with said solid active cathode.
3. The method of claim 1 wherein said additive is placed within said cell by dissolving said additive in said non-aqueous electrolyte.
4. The method of claim 1 wherein said quantity of said additive is of a magnitude whereby no more than 5% of the capacity of said active cathode is self discharged thereby.
5. The method of claim 1 wherein said additive comprises a member selected from the group consisting of Li2S, Na2S, K2S, MgS, CaS, Li2Se, Na2Se, K2Se, MgSe, CaSe, Li2Te, Na2Te, K2Te, MgTe and CaTe.
6. The method of claim 5 wherein said additive comprises Li2S.
7. The method of claim 1 wherein said active cathode is comprised of a member of the group consisting of beta-MnO2, TiO2, SnO, MoO3, V2O5, CrO3, PbO and Fe2O3.
8. The method of claim 1 wherein said electrochemical cell contains a lithium anode, a beta-MnO2 cathode and a non-aqueous electrolyte, said method comprising the step of mixing an additive selected from the group consisting of Li2S, Na2S, K2S, MgS, CaS, Li2Se, Na2Se, K2Se, MgSe, CaSe, Li2Te, Na2Te, K2Te, MgTe and CaTe with beta-MnO2, said additive being of sufficient quantity to self discharge substantially all of the surface area of said beta-MnO2 but less than sufficient to self discharge more than 5%
of the capacity of said beta-MnO2.
of the capacity of said beta-MnO2.
9. The method of claim 8 wherein said additive comprises Li2S.
10. A cell made in accordance with the method of claim 8.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US091,149 | 1979-11-05 | ||
| US06/091,149 US4298663A (en) | 1979-10-01 | 1979-11-05 | Predischarged nonaqueous cell |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1149451A true CA1149451A (en) | 1983-07-05 |
Family
ID=22226322
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363721A Expired CA1149451A (en) | 1979-11-05 | 1980-10-31 | Predischarged nonaqueous cell |
Country Status (18)
| Country | Link |
|---|---|
| US (1) | US4298663A (en) |
| JP (1) | JPS5682581A (en) |
| AU (1) | AU530125B2 (en) |
| BE (1) | BE886026A (en) |
| BR (1) | BR8007148A (en) |
| CA (1) | CA1149451A (en) |
| DE (1) | DE3041499A1 (en) |
| DK (1) | DK468080A (en) |
| ES (1) | ES496585A0 (en) |
| FR (1) | FR2469010B1 (en) |
| GB (1) | GB2064205B (en) |
| HK (1) | HK44088A (en) |
| IE (1) | IE52193B1 (en) |
| IT (1) | IT1195034B (en) |
| NL (1) | NL8005959A (en) |
| NO (1) | NO803307L (en) |
| SE (1) | SE8007728L (en) |
| ZA (1) | ZA806840B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4304764A (en) * | 1980-09-24 | 1981-12-08 | Ray-O-Vac Corporation | Protective active nitrides as additives to nonaqueous cathode materials |
| FR2493606B1 (en) * | 1980-10-31 | 1985-11-22 | Duracell Int | CATHODE STABILIZER AND METHOD FOR MANUFACTURING ELECTROCHEMICAL CELLS |
| US4343714A (en) * | 1980-12-03 | 1982-08-10 | Ray-O-Vac Corporation | Process for treating cathode material |
| US4407909A (en) * | 1981-07-23 | 1983-10-04 | Gte Products Corporation | Method for internally discharging an electrochemical cell |
| US4604335A (en) * | 1985-03-06 | 1986-08-05 | Rayovac Corporation | High rate cathode formulation |
| JPH0746608B2 (en) * | 1986-10-30 | 1995-05-17 | 三洋電機株式会社 | Non-aqueous secondary battery |
| US4911996A (en) * | 1988-03-11 | 1990-03-27 | Eic Laboratories, Inc. | Electrochemical cell |
| EP2023434B1 (en) * | 2007-07-23 | 2016-09-07 | Litarion GmbH | Electrolyte preparations for energy storage devices based on ionic fluids |
| JP6617750B2 (en) | 2017-05-23 | 2019-12-11 | トヨタ自動車株式会社 | Control device for vehicle drive device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3716403A (en) * | 1969-10-20 | 1973-02-13 | Molecular Energy Corp | A method of making semi-conductive cathodes |
| US3887397A (en) * | 1974-01-02 | 1975-06-03 | Honeywell Inc | Highly conductive stable electrolyte for lithium batteries |
| JPS5342325A (en) * | 1976-09-29 | 1978-04-17 | Sanyo Electric Co | Method of making cathode of nonnaqueous battery |
| US4048402A (en) * | 1976-12-27 | 1977-09-13 | Union Carbide Corporation | Non-aqueous cell having a cathode of lead monoxide-coated lead dioxide particles |
| US4163829A (en) * | 1977-11-14 | 1979-08-07 | Union Carbide Corporation | Metallic reducing additives for solid cathodes for use in nonaqueous cells |
| US4160070A (en) * | 1978-09-25 | 1979-07-03 | Esb United States, Inc. | Additive for high drain rate lithium cells |
| US4184017A (en) * | 1979-01-24 | 1980-01-15 | P. R. Mallory & Co. Inc. | Polyvalent metal anode containing cells |
| JPS5630263A (en) * | 1979-08-20 | 1981-03-26 | Matsushita Electric Ind Co Ltd | Manufacture of active material for positive electrode for battery with nonaqueous electrolite |
| FR2493606B1 (en) * | 1980-10-31 | 1985-11-22 | Duracell Int | CATHODE STABILIZER AND METHOD FOR MANUFACTURING ELECTROCHEMICAL CELLS |
-
1979
- 1979-11-05 US US06/091,149 patent/US4298663A/en not_active Expired - Lifetime
-
1980
- 1980-10-28 GB GB8034634A patent/GB2064205B/en not_active Expired
- 1980-10-28 AU AU63769/80A patent/AU530125B2/en not_active Ceased
- 1980-10-30 NL NL8005959A patent/NL8005959A/en not_active Application Discontinuation
- 1980-10-31 CA CA000363721A patent/CA1149451A/en not_active Expired
- 1980-11-04 SE SE8007728A patent/SE8007728L/en not_active Application Discontinuation
- 1980-11-04 IE IE2282/80A patent/IE52193B1/en unknown
- 1980-11-04 DK DK468080A patent/DK468080A/en unknown
- 1980-11-04 DE DE19803041499 patent/DE3041499A1/en active Granted
- 1980-11-04 NO NO803307A patent/NO803307L/en unknown
- 1980-11-04 BR BR8007148A patent/BR8007148A/en unknown
- 1980-11-05 BE BE2/58842A patent/BE886026A/en not_active IP Right Cessation
- 1980-11-05 ZA ZA00806840A patent/ZA806840B/en unknown
- 1980-11-05 FR FR8023623A patent/FR2469010B1/en not_active Expired
- 1980-11-05 ES ES496585A patent/ES496585A0/en active Granted
- 1980-11-05 JP JP15572080A patent/JPS5682581A/en active Granted
- 1980-11-05 IT IT25789/80A patent/IT1195034B/en active
-
1988
- 1988-06-09 HK HK440/88A patent/HK44088A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ZA806840B (en) | 1982-06-30 |
| FR2469010B1 (en) | 1985-08-16 |
| IT8025789A0 (en) | 1980-11-05 |
| JPS5682581A (en) | 1981-07-06 |
| BE886026A (en) | 1981-03-02 |
| GB2064205B (en) | 1983-03-16 |
| ES8303825A1 (en) | 1983-02-01 |
| DE3041499A1 (en) | 1981-05-14 |
| DE3041499C2 (en) | 1989-06-22 |
| SE8007728L (en) | 1981-05-06 |
| ES496585A0 (en) | 1983-02-01 |
| US4298663A (en) | 1981-11-03 |
| AU530125B2 (en) | 1983-06-30 |
| NL8005959A (en) | 1981-06-01 |
| AU6376980A (en) | 1981-05-14 |
| IE52193B1 (en) | 1987-08-05 |
| BR8007148A (en) | 1981-05-12 |
| FR2469010A1 (en) | 1981-05-08 |
| GB2064205A (en) | 1981-06-10 |
| JPH0353745B2 (en) | 1991-08-16 |
| HK44088A (en) | 1988-06-17 |
| IE812282L (en) | 1981-05-05 |
| DK468080A (en) | 1981-05-06 |
| NO803307L (en) | 1981-05-06 |
| IT1195034B (en) | 1988-09-28 |
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