GB1579714A - Rechargeable electrochemical cells - Google Patents
Rechargeable electrochemical cells Download PDFInfo
- Publication number
- GB1579714A GB1579714A GB7876/78A GB787678A GB1579714A GB 1579714 A GB1579714 A GB 1579714A GB 7876/78 A GB7876/78 A GB 7876/78A GB 787678 A GB787678 A GB 787678A GB 1579714 A GB1579714 A GB 1579714A
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- Prior art keywords
- cell
- negative electrode
- active material
- electrochemically active
- rechargeable
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- 239000011262 electrochemically active material Substances 0.000 claims description 31
- 150000004678 hydrides Chemical class 0.000 claims description 18
- 239000001257 hydrogen Substances 0.000 claims description 16
- 229910052739 hydrogen Inorganic materials 0.000 claims description 16
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 15
- 238000007599 discharging Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 13
- 239000007789 gas Substances 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 11
- 229910000765 intermetallic Inorganic materials 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 8
- -1 hydride form Chemical group 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 239000004020 conductor Substances 0.000 claims description 7
- 239000003792 electrolyte Substances 0.000 claims description 7
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 5
- 229910052746 lanthanum Inorganic materials 0.000 claims description 5
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052776 Thorium Inorganic materials 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 150000002431 hydrogen Chemical class 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 3
- 239000004800 polyvinyl chloride Substances 0.000 claims description 3
- 238000005245 sintering Methods 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 239000005749 Copper compound Substances 0.000 claims description 2
- 239000004677 Nylon Substances 0.000 claims description 2
- SHSXOJVRHAGLJK-UHFFFAOYSA-N [Ni].[Cu].[La] Chemical compound [Ni].[Cu].[La] SHSXOJVRHAGLJK-UHFFFAOYSA-N 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 claims description 2
- 230000002411 adverse Effects 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 238000004880 explosion Methods 0.000 claims description 2
- 239000007773 negative electrode material Substances 0.000 claims description 2
- 229920001778 nylon Polymers 0.000 claims description 2
- 238000002161 passivation Methods 0.000 claims description 2
- 230000002035 prolonged effect Effects 0.000 claims description 2
- 239000011810 insulating material Substances 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 9
- 239000011149 active material Substances 0.000 description 6
- 229910002640 NiOOH Inorganic materials 0.000 description 5
- 239000008151 electrolyte solution Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 229910002335 LaNi5 Inorganic materials 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- OJIJEKBXJYRIBZ-UHFFFAOYSA-N cadmium nickel Chemical compound [Ni].[Cd] OJIJEKBXJYRIBZ-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910021508 nickel(II) hydroxide Inorganic materials 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910010380 TiNi Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
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
- H01M10/24—Alkaline accumulators
-
- 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
- H01M10/34—Gastight accumulators
- H01M10/345—Gastight metal hydride accumulators
-
- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/383—Hydrogen absorbing alloys
-
- 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
Description
(54) RECHARGEABLE ELECTROCHEMICAL CELLS
(71) We, N.V. PHILIPS' GLOEILAMPENFABRIEKEN, a limited liability Company, organised and established under the laws of the Kingdom of the Netherlands, of Emmasingel 29, Eindhoven, the
Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a rechargeable electrochemical cell which is sealed from the external atmosphere and comprises a sealed chamber containing a positive electrode, the electrochemically active material of which can reversibly store and release a proton and an electron, a negative electrode the electrochemically active material of which consists of a metal combination which forms a hydride with hydrogen and an aqueous electrolyte solution having a pH of more than 7. In addition the cell may comprise a separator which electrically separates the electrodes but allows ion and gas transport. Hereinafter such a cell will be called a "sealed cell". However, if desired, such a cell may be provided with a valve which is dimensioned so that it becomes operative at a predetermined gas pressure in the cell. The invention also relates to a method of producing sealed cells.
A rechargeable, sealed cell of this type is, for example, disclosed in United
States Patent Specification No. 3,874,928. The electrochemically active material of the positive electrode in this known cell may consist of nickel hydroxide, silver oxide or manganese oxide, nickel hydroxide generally being preferred for practical reasons. The electrochemically active material of the negative electrode, may, for example, consist of an intermetallic compound of lanthanum and nickel having an empirical formula LaNi It is known that with hydride-forming intermetallic compounds of this nature, both the lanthanum and the nickel can be partially replaced by other metals, such as, as regards the lanthanum, for example, by calcium, thorium, titanium, yttrium or an element having an atomic number in the range from 58 to 71 inclusive, and as regards the nickel, for example, by copper, chromium and iron. (See, for example,
United Kingdom Patent Specification No. 1,463,248). If hereinafter Lands and intermetallic compounds derived therefrom by substitution with other metals are mentioned, then this should be understood to mean compounds which, in general, have the composition Lank,, wherein n may be between 4.8 and 5.4. This indicates compounds with CaCu5-crystal structure whose existence range includes Lands. The expression "existence range" is understood to mean a range of concentrations in a continuous system of intermetallic compounds with which an identical structure can be realized for 100 /" with or without a heat treatment.
When constructing systems which are sealed from the external environment and which comprise hydrides of intermetallic compounds, the hydrogen equilibrium pressure above the hydride and the working temperature of the system must be taken into account. For the hydride of Lands, this equilibrium pressure is approximately 2.5 Bar at 200 C. For the hydride of LaNi4Cu, this pressure is only about 0.7 Bar at 20"C and for the hydride of LaNi4Cr it is about 0.31 Bar at 200C. If the electrochemical properties are acceptable, the two latter materials will be preferred for producing sealed, rechargeable cells because the casing need not be so strong then. In general the electrolyte solution consists of an aqueous solution of one or more alkali metal hydroxides, such as lithium hydroxide and potassium hydroxide. The separator may consist of a synthetic fibre (woven or non-woven), for example of polyamide or polypropylene fibre. The operation of a rechargeable electrochemical cell of this type differs fundamentally from a so-called nickelcadmium battery, as a comparison of the electrochemical overall equations shows.
With a rechargeable cell to which the invention relates, this equation is of the following overall form, wherein nickel-hydroxide has been taken as the positive electrode material and the intermetallic compound is indicated by M:
charging Ni(OH2)+M, 'NiOOH+MH (1) discharging For the known nickel-cadmium secondary battery this equation may be written as:
charging 2Ni(OH)2+Cd(OH)2'- -- '2NiOOH+Cd+2H2O (2) discharging It will be seen that in the first case on charging as well as on discharging only a proton transfer takes place between the electrodes whereas the total quantity of electrolyte solution remains substantially constant. In the second case water is formed during charging, which water disappears again during discharging. In this cell measures must be taken to enable the storage of the formed water without this water obstructing the oxygen-gas transport between the electrodes. This required additional space in the battery casing, on the basis of this difference in electrochemical behaviour and also for other reasons, measures to solve problems inherent to the known nickel-cadmium cells cannot be applied to cells to which the invention relates. Such measures may even be superfluous in the latter cells as will be further explained below. With sealed, rechargeable cells of the type to which the invention relates, not only the hyrogen equilibrium pressure of the hydride of the intermetallic compounds as explained above is important, but also the phenomena which occur during overcharging and over-discharging of these cells. Overcharging is in practice a risk which must be taken into account when designing cells for rechargeable batteries. Over-discharging is a phenomenon which can occur if one or more of a plurality of series-arranged cells, for example in a battery having three or more cells, is fully discharged at an earlier instant than the other cells owing to differences in capacity which are unavoidable during fabrication. The battery then continues to supply current. Both overcharging and over-discharging can, if no special provisions are made in the cells, result in the occurrence of high gas pressures and, as the case may be, in explosive gas mixtures being expelled through a valve. This causes the cell to dry out and the charge equilibrium between the electrodes is disturbed.
The present invention has for its object to provide a rechargeable, sealed electrochemical cell of the type mentioned in the preamble of this specification in which provisions are made to maintain a reversible equilibrium in the cell in all circumstances and to prevent thus the occurrence of high gas pressures at overcharging and over-discharging as much as possible. The invention provides a rechargeable electrochemical cell which is sealed from the external environment.
Comprising in a chamber which is sealed from the environment a positive electrode, the electrochemically active part of which can reversibly store and release a proton, and an electron, a negative electrode, the electrochemically active part of which consists of a metal combination which forms a hydride with hydrogen, and an aqueous electrolyte having a pH exceeding 7, characterized in that the quantity of electrochemically active material of the negative electrode exceeds that of the positive electrode and that in the fully discharged state of the positive electrode the excess of the electrochemically active material of the negative electrode is at least as regards the excess, is partly present as a hydride (that is to say is in the charged state). Such a cell can be produced in accordance with one aspect of the invention by means of a method which is characterized in that when the electrodes are placed in the cell, the electrochemically active material of the positive electrode is in the discharged state and the electrochemically active material of the negative electrodes, at least as regards the excess, is partly present as a hydride (that is to say is in the charged state) and the cell is sealed in this state of the electrodes. In accordance with an other method, uncharged electrodes are placed in the cell, the cell is filled with the quantity of hydrogen required for partially charging the negative electrode and the cell is then hermetically sealed. Thereafter the cell is formed by successively charging and discharging it a number of times (for example five times). Such an excess of the electrochemically active material is preferably applied at the negative electrode relative to that at the positive electrode that the electrochemical capacity of the negative electrode exceeds the electrochemical capacity of the positive electrode by at least 15%. In principle the maximum excess is unlimited as will appear from the following explanation. In an embodiment, the electrochemical capacity of the negative electrode is about 1.5 times the electrochemical capacity of the positive electrode.
In a suitable embodiment, .if the positive electrode is fully discharged, approximately at least 10% and not more than 90 /n of the excess in capacity is still present at the negative electrode in the hydride form. This means that at the moment the positive electrode is fully charged, a minimum of 10% of the excess in capacity at the negative electrode is still in the uncharged state. When producing a cell according to the invention the negative electrode can, for example, be brought, prior to building-in, to a partly charged state. To this end the negative electrode can, for example, be brought to a partly charged state in an auxiliary cell by passing an electric current through it. The auxiliary cell comprises an inert electrode, of for example platinum, carbon, stainless steel or titanium, as the positive electrode.
This is, however, a cumbersome method. Preference is, therefore, given to the method explained above, in which the electrodes are introduced into the cell, this cell then being fillled with a hydrogen atmosphere.
An embodiment of the invention will now be described with reference to the accompanying drawing, in which: Figure 1 shows diagrammatically a cell according to the invention during discharging,
Figure 2 shows diagrammatically a cell according to the invention during charging, and
Figure 3 shows a cross-sectional view of a cell according to the invention.
In the cell according to the invention, whose wall is schematically indicated by means of a dotted line 1, there are in contact with an electrolyte solution, for example a SN solution of potassium hydroxide in water: a positive electrode A, whose electrochemically active material consists of nickel-hydroxide and a negative electrode B whose electrochemically active material consists of LaNi5,
LaNi4Cu or LaNi4Cr. The dimensions of the rectangles A and B are an indication of the relative quantity of electrochemically active compound at each of the electrodes. The hatched portion thereof indicates how much of the active material is in the charged state. The effect of the measure according to the invention is as follows.
During discharging (Figure 1) electrons flow through an electric conductor 2 from the negative electrode B to the positive electrode A. An electrode-chemical reaction takes place at the positive electrode, which can be expressed as follows NiOOH+H++e- < Ni(OH)2 (3) and at the negative electrode LaNi,H,-tLaNi,H,~,+Hf+e-. (4)
If the positive electrode is fully discharged, that is to say all the available NiOOH has been converted into Ni(OH)2, hydrogen ions can still form at the negative electrode in accordance with reaction equation (4) because a part of the active material is still in the hydride form. If the cell is connected in series with other cells which have not yet been fully discharged a current will continue to flow and, consequently, protons will flow in the electrolyte solution from the negative electrode to the positive electrode. Reactions take place then, which can be expressed as follows:
At the positive electrode H++e-o+H2 (5)
At the negative electrode: LaNi,H,LaNi,H,~,+H++e-. (6)
The hydrogen formed at the positive electrode diffuses to the negative electrode and reacts with discharged active material, which can, for example, be expressed as follows.
-LaNi5++H2-LaNi5H. (7)
x x
What comes as a surprise is that simultaneously, at the same electrode, hydrogen can be stored while forming a hydride and protons (H+) can be formed.
During charging of the cell (Figure 2) a reaction takes place at the positive electrode, which can be expressed as follows: Ni(OH)2~NiOOH+H++e-. (8) and at the negative electrode --LaNi,+Ht +e--, T-LaNi,H, (9)
x x
At the moment the active material at the positive electrode has been completely converted into the charged state (NiOOH), part of the active material at the negative electrode is still in the uncharged state. If now the charging current continues to flow reactions take place, which can be expressed as follows:
At the positive electrode oxygen gas is produced: 2H20 < 02+4H++4e-. (10)
At the negative electrode the above-mentioned reaction (8) continues. The oxygen formed diffuses to the negative electrode and reacts with the hydride while forming water, which reaction can, for example, be expressed as follows: LaNisHl+o2eLaNisHx-4+2H2o (Il) In practice this reaction appears to proceed at such a speed that the oxygen supplied is converted: In the reaction equations (4), (6), (7), (8) and (9) x may have a value between 4 and 6.
From the above it follows directly that the proposed measure, both during overcharging and during over-discharging prevents high gas pressures from occurring. It also appears that the proposed measure is permanently effective.
Other hydride-forming intermetallic compounds which may be used in the cell according to the invention are TiNi and Tire.
With the above mentioned nickel-cadmium cell, a so-cailed charge reserve (excess of active material at the negative electrode) is fully depleted in the course of time. With this cell the electrochemical capacity decreases if material of the negative electrode is over-discharged. A further advantage of the cell according to the invention consists in that the electro-chemically active material of the negative electrode may consist of a material such as LaNi4Cr which, as such, cannot properly stand up to overdischarging. In a cell according to the invention the hydride electrode never attains such a low potential that, for example, copper which may be used in an electrode construction obtained by sintering of the electrode material, for example LaNi5, starts corroding.
Cells according to the invention can be combined to form a secondary battery, for instance by connecting several cells in series.
An embodiment of a cell according to the invention will now be explained in greater detail with reference to the accompanying Figure 3.
The hermetically sealed cell shown in Figure 3 is manufactured using a suitable casing 1 of a metal such as stainless steel, provided with a cover 11 with openings through which conductors 3 and 4 are led out. The conductors are insulated from the metal cover I I by means of synthetic resin rings 5. Externally the casing has, for example, a diameter of 22 mm and a height of 41 mm. A wound section consisting of a negative electrode 6, a separator 7 and a positive electrode 8, this wound section further comprising an electrically insulating plastic film 9, for example of polyvinyl chloride and supported by a disc 10 of an electrically insulating material such as polyvinyl chloride, is introduced into the chamber of the casing. The negative electrode 6 consists of an intermetallic lanthanum nickel copper compound LaNi4Cu and is connected to the conductor 3. The negative electrode 6 is manufactured by sintering a suitable quantity of LaNi4Cu, mixed with copper powder (1:1 by volume). The positive electrode 8 is a nickel hydroxide electrode of the conventional, commerical sintered type, connected to the conductor 4. An aqueous 6N potassium hydroxide solution is used as an electrolyte and is absorbed in the separator 7, the electrolyte is in wet contact with the electrochemically active material of the two electrodes. The separator 7 consists of very finely woven nylon gauze. The electrochemical capacity of the negative electrode 6 is equal to 1.5 times the electrochemical capacity of the positive electrode 8, the latter having a capacity of 1.2 Ah. (I g of LaNi4Cu corresponds to about 0.26 Ah). Before being hermetically sealed the cell is filled with a quantity of hydrogen gas corresponding to 0.12 Ah, which corresponds to approximately 50 standard cm3 of H2 gas. After having been charged and discharged for 5 cycles, the hydrogen has been absorbed by the negative electrode, resulting in the formation of a negative reserve capacity. The free gas space in the cell is approximately 5 cm3.
A sealed cell of this type has an EMF of 1.3 V. Prolonged over-charging or overdischarging does not adversely affect the quality of the cell or create the risk for explosions.
A surprising feature of this cell is that passivation of the negative electrode material with respect to the absorption of hydrogen from the gas phase does not occur, which is usually the case when Lands and compounds derived thereform come into contact with oxygen and water or water vapour, respectively. It is assumed that this is associated with the fact that the cell is sealed from the external atmosphere.
WHAT WE CLAIM IS:
1. Rechargeable electrochemical cell which is sealed from the external environment, comprising in a chamber which is sealed from the environment a positive electrode, the elec.trochemically active part of which can reversibly store and release a proton and an electron, a negative electrode, the electrochemically active material of which consists of a metal combination which forms a hydride with hydrogen, and an aqueous electrolyte having a pH exceeding 7, characterized in that the quantity of the electrochemically active material of the negative electrode exceeds that of the positive electrode and that in the fully discharged state of the positive electrode the electrochemically active material of the negative electrode, at least as regards the excess, is partly present as a hydride (that is to say is in the charged state).
2. A rechargeable cell as claimed in Claim 1, characterized in that the quantities of electrochemically active material of the electrodes are chosen so that the electrochemical capacity of the negative electrode exceeds the electrochemical capacity of the positive electrodes by at least 15 /,.
3. A rechargeable cell as claimed in Claim 2, characterized in that the quantities of electrochemically active materials of the electrodes have been chosen so that the electrochemical capacity of the negative electrode is 1.5 times the electrochemical capacity of the positive electrode.
4. A rechargeable cell as claimed in Claim 1, characterized in that in the fully discharged state of the positive electrode at least 10% and not more than 90% of the excess in capacity of the negative electrode is in the hydride form (charged state).
5. A rechargeable cell as claimed in Claim 2, characterized in that the electrochemically active material of the negative electrode consists of an intermetallic compound of the type having the gross equation Lank,, n being between 4.8 and 5.4.
6. A rechargeable cell as claimed in Claim 5, wherein the lanthanum has been partly replaced by Ca, Th, Ti, Y or an element having an atomic number in the range from 58 to 71 inclusive.
7. A method as claimed in Claim 5 or Claim 6, wherein the nickel has been partly replaced by Co, Cr or Fe.
8. A method of producing a rechargeable cell as claimed in Claim I, characterized in that when placing the electrodes in the cell the electrochemically active material of the positive electrode is in the discharged state and the electrochemically active material of the negative as regards the excess of the electrochemical capacity is partly in the hydride form (charged state) and the cell is sealed in this state of the electrodes.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (12)
1. Rechargeable electrochemical cell which is sealed from the external environment, comprising in a chamber which is sealed from the environment a positive electrode, the elec.trochemically active part of which can reversibly store and release a proton and an electron, a negative electrode, the electrochemically active material of which consists of a metal combination which forms a hydride with hydrogen, and an aqueous electrolyte having a pH exceeding 7, characterized in that the quantity of the electrochemically active material of the negative electrode exceeds that of the positive electrode and that in the fully discharged state of the positive electrode the electrochemically active material of the negative electrode, at least as regards the excess, is partly present as a hydride (that is to say is in the charged state).
2. A rechargeable cell as claimed in Claim 1, characterized in that the quantities of electrochemically active material of the electrodes are chosen so that the electrochemical capacity of the negative electrode exceeds the electrochemical capacity of the positive electrodes by at least 15 /,.
3. A rechargeable cell as claimed in Claim 2, characterized in that the quantities of electrochemically active materials of the electrodes have been chosen so that the electrochemical capacity of the negative electrode is 1.5 times the electrochemical capacity of the positive electrode.
4. A rechargeable cell as claimed in Claim 1, characterized in that in the fully discharged state of the positive electrode at least 10% and not more than 90% of the excess in capacity of the negative electrode is in the hydride form (charged state).
5. A rechargeable cell as claimed in Claim 2, characterized in that the electrochemically active material of the negative electrode consists of an intermetallic compound of the type having the gross equation Lank,, n being between 4.8 and 5.4.
6. A rechargeable cell as claimed in Claim 5, wherein the lanthanum has been partly replaced by Ca, Th, Ti, Y or an element having an atomic number in the range from 58 to 71 inclusive.
7. A method as claimed in Claim 5 or Claim 6, wherein the nickel has been partly replaced by Co, Cr or Fe.
8. A method of producing a rechargeable cell as claimed in Claim I, characterized in that when placing the electrodes in the cell the electrochemically active material of the positive electrode is in the discharged state and the electrochemically active material of the negative as regards the excess of the electrochemical capacity is partly in the hydride form (charged state) and the cell is sealed in this state of the electrodes.
9. A method of producing a rechargeable cell as claimed in Claim 8,
charicterized in that the negative electrode prior to building in the rechargeable cell is electrically charged in an auxiliary cell.
10. A method as claimed in Claim 8, characterized in that prior to building the negative electrode into the rechargeable cell the negative electrode is exposed to a hydrogen atmosphere.
Il. A method of producing a rechargeable cell as claimed in Claim 1, characterized in the electrodes are placed in the cell in the uncharged state, the cell is filled with a quantity of hydrogen gas required for partly converting the electrochemically active material of the negative electrode into a hydride, whereafter the cell is sealed and the hydrogen is absorbed by the negative electrode repeated charging and discharging of the cell.
12. A rechargeable electrochemical cell substantially as hereinbefore described with reference to Figure 3 of the accompanying drawing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7702259A NL7702259A (en) | 1977-03-03 | 1977-03-03 | Rechargeable enclosed electrochemical cell - with negative electrode having much more electrochemically active material than positive electrode |
| NLAANVRAGE7801243,A NL176893C (en) | 1977-03-03 | 1978-02-03 | RECHARGEABLE ELECTROCHEMICAL CELL CONCLUDED FROM THE SURROUNDING ATMOSPHERE AND METHODS FOR MANUFACTURING SUCH CELLS. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1579714A true GB1579714A (en) | 1980-11-26 |
Family
ID=26645299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7876/78A Expired GB1579714A (en) | 1977-03-03 | 1978-02-28 | Rechargeable electrochemical cells |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS53111439A (en) |
| AT (1) | ATA143578A (en) |
| CA (1) | CA1097734A (en) |
| DE (1) | DE2808433C3 (en) |
| DK (1) | DK155859C (en) |
| FR (1) | FR2382776A1 (en) |
| GB (1) | GB1579714A (en) |
| IT (1) | IT1111422B (en) |
| NL (1) | NL176893C (en) |
| SE (2) | SE7802243L (en) |
| YU (1) | YU49478A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1402593A1 (en) * | 2001-06-29 | 2004-03-31 | Ovonic Battery Company, Inc. | Hydrogen storage battery; positive nickel electrode; positive electrode active material and methods for making |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4107395A (en) * | 1977-09-20 | 1978-08-15 | Communication Satellite Corporation | Overchargeable sealed metal oxide/lanthanum nickel hydride battery |
| ZA832570B (en) * | 1982-04-28 | 1984-01-25 | Energy Conversion Devices Inc | Improved rechargeable battery and electrode used therein |
| JPS59181459A (en) * | 1983-03-31 | 1984-10-15 | Toshiba Corp | Metal oxide hydrogen battery |
| JPS6119060A (en) * | 1984-07-04 | 1986-01-27 | Sanyo Electric Co Ltd | Hydrogen occlusion electrode |
| US4621034A (en) * | 1984-07-31 | 1986-11-04 | Kabushiki Kaisha Toshiba | Sealed metal oxide-hydrogen storage cell |
| JPH0642374B2 (en) * | 1984-10-18 | 1994-06-01 | 三洋電機株式会社 | Metal-hydrogen alkaline storage battery |
| FR2569059B1 (en) * | 1984-08-10 | 1992-08-07 | Sanyo Electric Co | ALKALINE METAL / HYDROGEN ACCUMULATOR |
| JPS6149375A (en) * | 1984-08-17 | 1986-03-11 | Matsushita Electric Ind Co Ltd | Manufacture of hydrogen absorbing electrode |
| JPS61118963A (en) * | 1984-11-13 | 1986-06-06 | Sharp Corp | Hydrogen-occlusion electrode |
| JPS61140075A (en) * | 1984-12-12 | 1986-06-27 | Matsushita Electric Ind Co Ltd | Manufacture of alkaline battery |
| JPS61168871A (en) * | 1985-01-19 | 1986-07-30 | Sanyo Electric Co Ltd | Hydrogen occlusion electrode |
| JPS6332962U (en) * | 1986-08-20 | 1988-03-03 | ||
| US4716088A (en) * | 1986-12-29 | 1987-12-29 | Energy Conversion Devices, Inc. | Activated rechargeable hydrogen storage electrode and method |
| US4935318A (en) * | 1987-03-25 | 1990-06-19 | Matsushita Electric Industrial Co., Ltd. | Sealed type nickel-hydride battery and production process thereof |
| DE4029503A1 (en) * | 1990-09-18 | 1992-03-19 | Emmerich Christoph Gmbh Co Kg | Safely over-(dis)charged and hermetic nickel hydride cells - uses additive of hydrogen catalysts e.g. raney metal in negative electrode mass and positive metal oxide electrode |
| JPH0465663U (en) * | 1990-10-11 | 1992-06-08 | ||
| JP3025770B2 (en) * | 1994-10-24 | 2000-03-27 | 株式会社東芝 | Metal oxide / hydrogen battery |
| FR2797526B1 (en) * | 1999-08-09 | 2001-10-12 | Cit Alcatel | WATERPROOF NICKEL-METAL WATERPROOF BATTERY |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL94733C (en) * | 1949-11-22 | |||
| CH495060A (en) * | 1967-05-02 | 1970-08-15 | Battelle Memorial Inst Interna | Accumulator electrode with storage capacity for hydrogen and process for their production |
| CA1009301A (en) * | 1970-08-03 | 1977-04-26 | John L. Devitt | Maintenance-free lead-acid sealed electrochemical cell with gas recombination |
| US3669744A (en) * | 1971-02-25 | 1972-06-13 | Tsenter Boris I | Hermetically sealed nickel-hydrogen storage cell |
| IT974430B (en) * | 1972-01-08 | 1974-06-20 | Deutsche Automobilgesellsch | PROCEDURE FOR THE MANUFACTURE OF HYDROGEN STORAGE ELECTRODES FOR ELECTRIC ACCUMULATORS |
| US3867199A (en) * | 1972-06-05 | 1975-02-18 | Communications Satellite Corp | Nickel hydrogen cell |
| US3850694A (en) * | 1972-11-27 | 1974-11-26 | Communications Satellite Corp | Low pressure nickel hydrogen cell |
| US3874928A (en) * | 1973-06-29 | 1975-04-01 | Gen Electric | Hermetically sealed secondary battery with lanthanum nickel anode |
| DE2527173A1 (en) * | 1974-06-19 | 1976-01-02 | Western Electric Co | ENERGY CONVERTER IN WHICH CHEMICAL ENERGY IS CONVERTED INTO ELECTRICAL |
| US3980501A (en) * | 1974-06-19 | 1976-09-14 | Bell Telephone Laboratories, Incorporated | Use of hydrogen-absorbing electrode in alkaline battery |
| NL7411045A (en) * | 1974-08-19 | 1976-02-23 | Philips Nv | RECHARGEABLE ELECTROCHEMICAL CELL. |
| DE2452064C3 (en) * | 1974-11-02 | 1981-06-19 | Varta Batterie Ag, 3000 Hannover | Gas-tight sealed alkaline accumulator |
-
1978
- 1978-02-03 NL NLAANVRAGE7801243,A patent/NL176893C/en not_active IP Right Cessation
- 1978-02-27 DE DE2808433A patent/DE2808433C3/en not_active Expired
- 1978-02-28 CA CA297,860A patent/CA1097734A/en not_active Expired
- 1978-02-28 DK DK091578A patent/DK155859C/en not_active IP Right Cessation
- 1978-02-28 GB GB7876/78A patent/GB1579714A/en not_active Expired
- 1978-02-28 AT AT143578A patent/ATA143578A/en not_active IP Right Cessation
- 1978-02-28 SE SE7802243D patent/SE7802243L/en not_active Application Discontinuation
- 1978-02-28 SE SE7802243A patent/SE440712B/en not_active IP Right Cessation
- 1978-03-01 JP JP2216978A patent/JPS53111439A/en active Granted
- 1978-03-01 IT IT67419/78A patent/IT1111422B/en active
- 1978-03-02 FR FR7805981A patent/FR2382776A1/en active Granted
- 1978-03-02 YU YU00494/78A patent/YU49478A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1402593A1 (en) * | 2001-06-29 | 2004-03-31 | Ovonic Battery Company, Inc. | Hydrogen storage battery; positive nickel electrode; positive electrode active material and methods for making |
| EP1402593A4 (en) * | 2001-06-29 | 2009-04-29 | Ovonic Battery Co | Hydrogen storage battery; positive nickel electrode; positive electrode active material and methods for making |
Also Published As
| Publication number | Publication date |
|---|---|
| IT7867419A0 (en) | 1978-03-01 |
| JPS53111439A (en) | 1978-09-29 |
| IT1111422B (en) | 1986-01-13 |
| CA1097734A (en) | 1981-03-17 |
| NL7801243A (en) | 1978-09-05 |
| NL176893B (en) | 1985-01-16 |
| DE2808433C3 (en) | 1981-06-25 |
| FR2382776A1 (en) | 1978-09-29 |
| DK155859C (en) | 1989-10-09 |
| DE2808433A1 (en) | 1978-09-07 |
| SE440712B (en) | 1985-08-12 |
| FR2382776B1 (en) | 1983-09-02 |
| ATA143578A (en) | 1980-10-15 |
| JPS615264B2 (en) | 1986-02-17 |
| DE2808433B2 (en) | 1980-07-10 |
| DK155859B (en) | 1989-05-22 |
| SE7802243L (en) | 1978-09-04 |
| YU49478A (en) | 1983-01-21 |
| DK91578A (en) | 1978-09-04 |
| NL176893C (en) | 1985-06-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PE20 | Patent expired after termination of 20 years |
Effective date: 19980227 |