CA2218709C - Rechargeable lithium battery having improved reversible capacity - Google Patents
Rechargeable lithium battery having improved reversible capacity Download PDFInfo
- Publication number
- CA2218709C CA2218709C CA002218709A CA2218709A CA2218709C CA 2218709 C CA2218709 C CA 2218709C CA 002218709 A CA002218709 A CA 002218709A CA 2218709 A CA2218709 A CA 2218709A CA 2218709 C CA2218709 C CA 2218709C
- Authority
- CA
- Canada
- Prior art keywords
- battery
- lithium
- lithium battery
- rechargeable lithium
- lithium ions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- 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
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0438—Processes of manufacture in general by electrochemical processing
- H01M4/044—Activating, forming or electrochemical attack of the supporting material
- H01M4/0445—Forming after manufacture of the electrode, e.g. first charge, cycling
- H01M4/0447—Forming after manufacture of the electrode, e.g. first charge, cycling of complete cells or cells stacks
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0438—Processes of manufacture in general by electrochemical processing
- H01M4/0459—Electrochemical doping, intercalation, occlusion or alloying
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
-
- 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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
-
- 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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M2010/4292—Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
-
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
-
- 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)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
An improved rechargeable lithium battery is described comprising a transition metal compound as cathode active material and carbonaceous particles as anode active material, having prior intercalated lithium ions in the carbonaceous particles in the anode of the assembled lithium battery, thereby reducing the weight of the cathode active material required. The rechargeable lithium battery has increased energy density per unit weight and per unit volume.
Description
qitle ~ Rr-F~ART~ .L~ lU.I BA~ ERY HAVING l.~ KUV~
~;VI~:~TRT.~ CAPACIq~Y
FT~Tn OF lNv~NllON
This invention is related to rechargeable non-aqueous lithium batteries.
~Ar ~n~ N V . .- l lON
Most rechargeable lithium ion batteries have a negative electrode cont~inin~ elemental lithium, which is usually intercalated in some carho~c~sus substance, a positive el~uLLode bearing a chalcogenide, which is capable of incol~o aLing lithium ions in its structure, an electrolyte cont~;ning mobile lithium ions, located between the negative and positive ele~L-odes and, optionally, a separator. The positive electrode also contains lithium either as ions in~vl~ulated in the structure of the chalcogenide or as a lithium compound having ~ ociable lithium ions ready to be in~o~ yuL ated in the structure of the chalcogenide, a binder mixed with the chalcogenide, and optionally carbon added to increase the ~o~t~ctivity of the mixture. The chalcogenide in the positive electrode is usually a transition metal oxide but may also be a transition metal sulphide. In some instances the chalcogenide may be replaced with a suitable organic compound. The electrolyte is commonly a solid organic polymer or a non-aqueous li~uid, which has a lithium salt dissolved in 2g it or contains ~;~cociable lithium ions in some other form.
The electrolyte may also be a mi~;lu~oLous solid polymer which has been impregnated with an organic liquid cont~i ning a ~iccOciable lithium salt. The electrolyte which is non-conductive of ele~L~ s, provides ionic ~QC~e for the ~ 30 lithium ion~. Lithium ions move from the elemental lithium cont~ining negative electrode or anode to the transition metal oxide con~;ning positive electrode or cathode, on discharge of the battery. Lithium ions are moved from the cathode or positive electrode through the e~ectrolyte to the negative ele~L~ode in the charging step.
The common practice in constructing a rechargeable CA 022l8709 l997-l0-2l lithium battery is that the carbonaceous particles capable of intercalating lithium ions, added to serve as the cathode active material in the negative electrode of the battery often as compacted into a layer with the aid of an organic b~nder compound, are provided in the battery initially without having any lithium content. The lithium ions to be utilized in the battery are usually added as a component in the transition metal oxide capable of incorporating lithium ions in its structure in the positive electrode, and in the non-aqueous lithium bearing electrolyte. It is to be noted that this procedure is common in assembling planar, spirally wound and button shaped rechargeable lithium batteries. The assembled lithium battery is first charged by applying a voltage of about 4.5 volts between the electrodes of the lithium battery to move the lithium ions in the positive electrode for intercalation in the carbonaceous particles constituting the negative electrode. Most of the lithium added in the positive electrode can be moved by applying an electric charge, however, there is a limit of the lithium concentration within the transition metal oxide below which the oxide crystal structure is irreversibly changed. Furthermore, the first charging of the assembled battery is a slow process to be conducted under carefully controlled conditions.
The portion of the lithium ions moved out o~ the lithium-transition metal compound serving as the positive active material, by the imposed external potential for intercalation in the carbonaceous particles, will be permanently lodged in or attached to the surface of the carbonaceous particles serving as the negative active material, or will be appended to the interface between the carbonaceous particles and the non-aqueous electrolyte. The type of bonding by which a portion of the lithium ion becomes immobilizable is not known exactly; the bonding of the immobilizable lithium may be related to the structure of the carbonaceous particles or to the nature of the bonding of the mobile lithium ion in the electrolyte, or to the interaction between the lithium bearing electrolyte and the lithium intercalated in the carbonaceous particles or to similar features of the lithium battery, -however, such immobilizable portion of the lit~ium ion initially present in the rechargeable lithium battery is lost to subsequent charging-discharging process steps. The portion of the lithium ions that becomes non-mobilizable in subse~uent charging-discharging process steps usually constitutes 20-3~%
or even higher, of the total amount o~ lithium contained in the rechargeable lithium battery and is usually referred to as the irreversible capacity loss of the lithium ~attery. The non-mobilizable lithium portion, that is the iLl~ersible capacity, will thus be influ~n~ by many factors such as the sites available for the lithium ion for intercalation, i.e.
the nature of the carbon particles utilized, the nature and type of non-a~ueous lithium bearing electrolyte employed, as well as the kind o~ transition metal oxide utilized in the positive electrode. U.S. Patent 5,34~,670 issued to Norio Takami et al. on Au~ust 23, 1994, describes as the negative ac~ive material in a rechargeable lithium battery, graphite particles ob~ in a high temperature treatment step and of specific crystal structure, having advantageous properties with respect to irreversible capacity }oss. U.S. Patent 5,432,029 issued to Takehito Mitate et al~ on July 11, 1995, teaches the utilization of copper oxide attached to the graphite or similar carbonaceous particles incorporated in the negative ele~LLvde for diminishing the irreversible capacity loss in a rechargeable lithium battery. Domini~ue Guyomard et al. in U.S. Patent 5,422,203 issued on June 6, 1995, describe a lithium bearing electro7yte composition to be utilized for reducing the irreversible capacity loss in a lithium battery.
The above are merely listed as examples of attempts of defining the nature of irreversible capacity loss in a rechargeable lithium battery and methods f~or dimi ni~:h;rlg such irreversible capacity losses.
lt can be seen that the irreversible capacity loss of a rechargeable lithium battery may be related to both the negative active material and to the positive active material.
It is to be noted that the type of irreversibility associated with the negative electrode and its interface with the electrolyte is different from the i~Le~ersi~ility exhibited by _ CA 022l8709 l997-l0-2l the positive active material in the positive electrode, however, both kinds of irreversibilities are usually compensated by adding ~n excess amount of lithium containing transition metal compound to the battery. The excess lithium-transition metal compound is a necessary component of aconventional lithium battery but is not taking part in subsequent charging-recharging steps and may amount to 2S~ or more extra battery weight. The mobilizable lithium ion portion in the rechargeable lithium battery, related to the carbonaceous particles in the negative ele~LL~de, is usually referred to as the anode specific reversible capacity measured in milliampere-hours per gram of carbonaceous particles (mAh/g~), and that related to the transition metal compound in the positive electrode, is usually referred to as the cathode specific reversible capacity measured in milliampere-hours per gram of transition metal compound ~mAh/gc~.
It is also to be noted that the first charging step due to its prolonged nature and controlled conditions, is costly even if excess lithium is added in the form of extra lithium-transition metal compound. There are known methods forincorporating lithium in the carbonaceous particles prior to assembling the lithium battery comprising an electrolyte and negative and positive electrodes. ~.S. Patent 4,980,250 issued to Yuzuru Tak~h~ch; et al. on December 25, l990, describes carbon moulded articles made of carbon fibre or carbon powder having lithium introduced electrolytically in the moulded article prior to the incorporation of the carbon moulded article into a lithium battery. Cheng-Kuo Huang et al. in U.S. Patent 5,436,093, teach a method for introducing lithium into carbon particles from a li~uid electrolyte containing lithium ions by the application of more than one electrical charging steps. The carbon particles are carried by a nickel grid acting as the negatively charged electrode.
The positive electrode in the pretreatment process is at least one lithium sheet immersed in the electrolyte. The lithium containing carbon particles are withdrawn from the pretreating electrolyte and are- used subsequently as negative active material in a rechargeable lithium battery. There is, CA 022l8709 l997-l0-2l however, no clear indication that all or any portion of the lithium introduced by the above described methods contributes to the reversible anode capacity of the carbon particles in subseguent repeated charging-discharging of the obtained lithium battery, thereby eliminates the need for adding an extra amount of lithium ion con~in;ng transition metal compound to operate the rechargeable lithium ion battery satisfactorily, and hence provide a lighter lithium battery.
cU4~RY O~ ~l~ INVENTION
one of the objects of ~he present invention is to provide a rechargeable lithium battery which incorporates the non-mobilizable lithium ion portion in the negative electrode coupled to the non-aqueous electrolyte in the lithium battery in the stage prior to the final packaging of the rechargeable lithium battery and prior to the full charging of the battery, thereby avoiding having to add extra weight in the positive electrode.
Another object of the present invention is to reduce the length of time required in the first full charging step of the assembled lithium battery.
Yet another object of the present invention is to provide substantially all the mobilizable lithium ion portion as tha~
contained in the positive electrode and the dissociable lithium ion in the non-aqueous electrolyte of the resulting assembled lithium battery, and thereby obtaining a lithium battery having high energy density per unit weight.
A rechargeable lithium battery is described hereinbelow which has improved reversible capacity. The improved rechargeable lithium battery has a positive electrode comprising a transition metal compound capable of incorporating lithium ions in its structure as the positive active ~aterial in the cathode, the cathode having a cathode specific reversible capacity (mAh~gc)~ a negative electrode con~i n; ng carbonaceous particles capable of intercalating lithium ions as the negative active material in the anode, the anode having an anode specific reversible capacity (mAh/gn), as well as a non-aqueous electrolyte conductive of lithium ions, and a total amount of lithium ions distributed between the e~ectrodes and the non-agueous lithium ion bearing electrolyte. In the improved rechargeable lithium battery of the present invention the weight of the negative active material in the negative electrode (wn) and the weight of the positive active material in the positive electrode (wc) are adjusted such that the ratio of the anode specific reversible capacity multiplied by the weight of the negative active material contained in the rechargeable lithium battery to the cathode specific reversible capacity multiplied by the weight of the positive active material contained in the rechargeable lithium ion battery has a value between 0.85 and 1.15, that is mAh/g~ x w~ : mAh/gc x WC = 0.8~ - 1.15. The i,..~ved rechargeable lithium battery has an energy density in excess of 3?0 watt.hour/liter or 130 watt.hour/kg.
BRI~F D~rRTPTION 0~ THR DRAWINGS
Figure l is a schematic circuit diagram illustrating the initial transfer of lithium into the anode of the lithium battery according to the present in~ention.
Figure 2 shows the performance of a lithium battery of the present invention in repeated charging-discharging cycles.
n~T~TT,~ ~R~RTP$ION QF l~ PR~ EMBODIHENTS
As it has been briefly mentioned above, the energy density per unit weight of a rechargeable lithium battery is of significance in the commercial utilization of lithium batteries, in particular of planar lithium batteries. One of the desired features in lithium battery ~echnology is to reduce the weight of the battery components as ~uch as it is possible without loss of battery efficiency and ouL~uL.
3Q The transition metal compound utilized in rechargeable lithium batteries is usually a transition metal chalcogenide, most frequently a transition metal oxide but may also be a transition metal sulphide. The c ~-~ition of the transition metal oxide incorporating lithium ions in its structure depends on the type and kind of transition metal oxide utilized. For example, lithium-cobalt oxide has a ~l ~v~ition -W O 97/31401 PCT/C~97/00097 - 7 -of LixCoO2, where x is less than 1, similarly lithium bearing nickel oxide has a composition of LixNiO2. On the other hand, lithium bearing manganese oxide may be described as LiyMn2O4, where 0~y<2. The transition metal compound may also be an 5 oxide of chromium, copper, vanadium, Lu~ly~Len or alloys of the above mentioned metals with other metals, which are capable of incorporating lithium ions in their structure. The most often utilized transition me~al sulphide is TiS2, but other transition metal sulphides, such as iron sulphide, may also serve as cathode active materials. Some organic compounds which are capable of incorporating lithium ions reversibly and are also electronic conductors, may also be utilized in the positive electrode of a rechargeable lithium battery. In theory, ~irtually all the lithium ions incorporated in the structure of transition metal compound may be moved by an imposed direct potential, however, as mentioned above, below a certain lithium concentration that is characteristic of each transition metal compound, the crystal structure, in particular the lattice dimensions of the transition metal compound is likely to change irreversibly. Hence a certain portion of the lithium in the battery has to be retained in the positive ele~Lro~e being incorporated in an unavoidable extra cathode material wei~ht. The positive electrode may also contain fine carbon to increase the electrical conductivity of the el~Llode and a binder substance. The positive electrode is usually in contact with some form of a current collector.
The cathode or positive electrode of a rechargeable lithium battery will have a reversible capacity der~n~;ng on the nature of the cathode active material contained in the electrode and to a lesser degree, on the binder. The cathode specific reversible capacity is usually calculated per unit weight of the cafhode active material in the electrode and is expressed in milliampere-hours per gram (m~h/gG).
3~ The non-a~ueous electrolyte of a rechargeable lithium battery is usually either a solid polymer electrolyte contA;nin~ lithium in a ~iccociable form, or a porous polymer separator impregnated with an organic li~uid containing dissolved therein a llthium salt capable of dissociating.
For obvious reasons, the electrolyte is conductive only of ions and non-conductive of electrons. There are various ways to keep the electrolyte weight in the battery as low as possible, which is beyond the scope of the present invention.
The negative electrode o~ a rechargeable, or secondary lithium battery usually has some form of ~arbonaceous particles capable of intercalating lithium, as the negative active material. The carbonaceous particles most often utilized in a rechargeable lithium battery include graphite, glassy or pyrolytic carbon, petroleum coke, carbon fibres and any other form of carbon particles that can intercalate lithium under normal circumst~c~. The preferred particle size of the carbonaceous particles is less than 60~ but ~reater than 5~. It is known that the lithium intercalated in carbon has the general formula of LiC6 but other lithium to carbon ratios have also been recorded. It is also known that a portion of the lithium subse~uent to the first introduct~on of lithium into the carhon~ceous particles, that is in the initial lithium charging step of a lithium battery, is irreversibly retained in the carbon structure. As discussed above, it is not known exactly whether the irreversibly bonded lithium attaches itself to some structural elements of the carbon or to the surface of the particles, or is located on the interface between the carbonaceous particles and the lithium ion con~llcting electrolyte. It has been observed that such irreversible capacity loss may depend on the type and history of the carbonaceous particles, on the binder substance utilized, on the nature of the electrolyte composition and so forth. Whatever is the reason, a portion of the transferred lithium is lost for subsequent battery charging~ çh~ging process steps. As mentioned hereinabove, in conventional rechargeab}e lithium batteries the irreversibly bonded lithium is compensated by an extra amount of lithium-transition metal compound ~e~ in the cathode, thus increasing the total weight of the battery.
The anode or negative ele~L~vde o~ a rechargeable lithium battery will have a reversible capacity der~nd; ng on the -PCT/C~97/00097 g na~ure of the cathode active material, that is on the type of carbonaceous particles contained in the anode and to a limited degree, on the binder. The anode specific reversible capacity is usually calculated per unit weight of the anode active ma~erial present in the electrode and is expressed in milliampere-hours per gram (mA~/g,).
It is known to introduce lithium into the carbonaceous particles by various methods prior to the carbonaceous material ~eing incorporated in the anode of the lithium battery, however it is believed, these methods have not been successful in eliminating an additional irreversible capacity loss that occurs during the first charging of the lithium battery. In other words, an extra amount of lithium-transitional metal compound is still needed over and above the reversibly incorporated lithium requirement of the carbonaceous particles in the anode.
It has now been surprisingly found that if the lithium is added electrolytically during the first chargin~ of the assembled rechargeable lithium ~attery in such a manner that the lithium transferred from the positive electrode for initially charginq the anode, is replaced from a third lithium electrode, no extra amount of lithium-transition metal compound is required to compensate for the irreversible capacity loss in the ~no~e. The im~ved rechargeable lithium battery of the present invention undergoes a first charging or pre-charging step of the battery in an electrical circuit which incorporates a third lithium cont~;ning electrode, which is most often an elemental lithium bearing electrode. The third ele~L-ode is separated from the lithium-transition metal compound cont~;n;ng cathode by another non-aqueous lithium ion containing electrolyte but is electrically ~ionically~ in contact with it. In practice, a positive potential is applied to the third, usually elemental lithium cont~;n;ng electrode, thereby forcing lithium ions to enter into the electrolyte separating the third electrode from the lithium-transition metal ~l~oul,d cont~;n;ng cathode of the lithium battery. The arriving lithium ions,- in turn, force an equivalent amount of lithium ions to leave the cathode to enter by way of the -CA 022l8709 l997-l0-2l electrolyte within the lithium battery into the anode to be intercalated by the carbonaceous particles in the negative electrode. As usual in the charging step, the anode carries a negative potential, thus closing the circuit. The pre-charging is conducted at the usual charging potential of alithium ~attery, that is at about 4.5 volts at the conventionally required current density for an appropriate length of time. The assembled pre-charged lithium battery is disconnected from the third e~ectrode and the additional or temporary electrolyte, and is subse~uently sealed and packaged with appropriate current collectors and electric leads in the usual manner.
The temporary electrolyte in contact with the third ele~Llode cont~;n;ng a source of lithium ions may have the same composition as the electrolyte of the assembled rechargeable lithium battery, or may be a different electrolyte such as an organic liquid having a lithium salt dissolved therein. The third ele~L~ode may ~e a lithium foil immersed in the organic li~uid or an alloy of lithium or may be another lithium ion con~; n; n~ f - , - und. Any convenient lithium source that is capable of providing lithium ions to the positive electrode of the rechargeable lithium ~attery and can be incorporated in an electrical circuit, is suitable for facilitating the pre-charging of the rechargeable lithium battery in accordance with the present invention. Fig.1 represents a schematic diagram of the electrical circuit of the pre-charging process step of the battery, where 2 is the negative electrode bearing carho~r~ous particles which do not contain any lithium before the pre-charging process step, 4 represents the lithium battery electrolyte and 6 is the lithium-transition metal com~oulid con~in;~g positive electrode. The positive electrode is in contact with the pre-charging temporary electrolyte 8, which in turn is in electrolytic contac~ with the third, usually but not nec~rily, elemental lithium cont~;n;ng electrode 10. In the preferred embo~i --L the third electrode is lithium metal or an elemental lithium cont~;n;ng alloy. Reference numeral 12 represents the external potential source, providing the CA 02218709 l997-l0-2l W O 97/31401 ~ PCT/CAg7/00097 - current for the pre-charging process step of the rechargeable lithium battery. The broken line 14 around the schematically drawn rechargeab~e lithium battery components represents conventional sealers, ~r L ~"t collectors and electrical leads which encase the rechargeable lithium battery subsequent to the pre-charging step.
For the sake of clarity, in the present description pre-charging of the lithium battery is understood to mean the first transfer of lithium ions to be intercalated in the carbonaceous particles of the anode or negative electrode, by means of applying a positive electrical potential to a third electrode which acts as a source of lithium ions. In the pre-charging step the third electrode is connected by means of a non-a~ueous electrolyte referred to as temporary electrolyte, to the positive electrode of the lithium battery. The temporary electro~yte is disconnected from the lithium battery after the pre-charging has taken place.
It is noted that the rechargeable lithium battery may not be fully charged in the pre-charging step and additional 20' charging of the lithium battery may still be re~uired after the rechargeable lithium battery has been separated from the third electrode and its electrolyte, sealed and packaged in the conventional manner. Whether the battery i5 fully charged or only partially charged in the pre-charging step, depends on the composition of the cathode active material and may also be dictated by other aspects of convenience. Optionally, the fully pre-charged lithium battery is allowed to discharge to attain its conventional low voltage level and is subsequently packaged and sealed.
one of the important features of the present invention i5 that the bonding between the electrolyte, shown as 4 on Fig.l, and the lithium bearing carbonaceous partic-e-cont~;n;ng anode 2 formed in the pre-charging step, is not disL~.bed or broken in the subsequent sealing and packaging of the rechargeable lithium battery. In other words, the lithium is transferred through the same electrolyte-anode interface in the pre-charging step as in subsequent charging-discharging steps taking place in utilizing the rechargeable lithium battery of the present inventio~.
The a~ove described pre-charging process may ~e applied to planar, spirally wound and button-shaped rechargeable lithium batteries.
The specific reversible capacity of a rechargeable lithium battery refers to the total reversible capacity of the assembled lithium ~attery and is expressed in milliampere-hours per the total weight of the active components of the lithium battery, that is the sum of the weights of the anode active material, the cathode active material and the non-aqueous electrolyte comprised in the lithium battery ~mAh/gt).
The reversible capacity of the rechargeable lithium battery made in accordance with the present invention is usually not much lower than the value of the lesser of the reversible capacities of the electrodes. It should be noted that in practical applications the values of the electrode reversible capacities within a rechargeable lithium battery are similar to one another.
The present invention will now be illustrated by working examples.
~XAMPLE 1 A commercially available planar rechargeable lithium battery A, having lithium-cobalt oxide as cathode active component and graphite as anode active component, was charged in the conventional manner by applying 4.2 volts to its external electrical leads at a current level controlled to complete charging in a 24 hour period. After charging battery A exhibited full battery voltage o~ 4.05 volts. Battery A had conventional anode film made of graphite of average particle size of 15~, cont~;ning 5 wt% polyvinylidene fluoride binder.
The electrolyte of battery A was porous polyethylene impregnated with ethylene carbonate-diethyl carbonate mixed in 1:1 ratio, cont~; n; ng LiPF6 in 1.0 mole concentration. It is known that conventional lithium-cobalt oxide has specific reversible capac~ty of 123 mAh/g. The specific anode reversible capacity of-the graphite utilized in the ~attery is 370 mAh/g. The reversible capacity of battery A was measured W O 97t31401 PCT/CA9710~097 - 13 -in the usual manner and the component layers of battery A were subse~uently separated and analyzed. The specific reversible capacity of lithium battery A was then obtained as 52 mAh/gt;
in the calculation gt was the sum total of the weights o~ the anode active graphite, cathode active lithium-co~alt oxide and the impregnated microporous polyethylene electrolyte comprised in a 100 cm2 area of battery A. The 100 cm2 segment of battery A was fo~nd to contain 1.35 g anode active graphite particles and 6.08 g cathode active lithium-cobalt oxide, that is the weight ratio of graphite to lithium-cobalt oxide in the anode and cathode layers respectively, was found to be 4:18. It was calculated that the value of the ratio of the anode capacity to the cathode capacity of battery A, that is: mAh/g~ x w~
divided by mAh/gc x wc = 370 x 1.3~ : 123 x 6.08 = O.67. This ratio is well below 1, thus indicating that excess weight is carried in the cathode.
Battery B was made up of the same commercially available lithium-cobalt oxide and graphite particles, utilizing the same amount of polyvinylidene fluoride binder and other additives in the anode and cathode, respectively, as in battery A, however, the weight ratio of the anode active graphite particles to the cathode active lithium-cobalt oxide was 4:13.2. The electrolyte of battery B had the same composition as that of battery A, but the weight per unit area 2~ of battery B was lower than that of battery A. The assemblad lithium battery B was immersed in an electrolyte solution made of ethylene carbonate-diethyl carbonate, containing LiP~6 in 1 Molar concentration. A 1 mm thick lOo mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A direct potential of 4.2 volts was applied between the lithium foil-third electrode and the anode of lithium battery B con~;ning graphite particles as negative active material, the latter having negative polarity in the circuit. The direct current was applied until the anode of lithium battery B attained a potential of 2.9 volts against the lithium-cobalt oxide bearing cathode of lithium battery B.
Battery B was then disconnected from the pre-charging direct potential and removed from the temporary electrolyte. Battery CA 022l8709 l997-l0-2l _ - 14 -B was subsequently fitted with appropriate current collectors and electrical leads, and sealed in the conventional manner.
Battery B was then charged to the full potential value it was capable of at~;n;ng, i.e. 4.05 volts, in conventional manner.
Battery B was subjected to several charging-discharging cycles and it was found to perform 3ust as satisfactorily as battery A under similar cycling conditions.
In a subse~uent series of tests the capacity of battery ~ was first measured in charging and discharging cycles at 25 mA current, which was then followed by charging and discharging cycles conducted at 40 mA current. The reversible capacities manifested in the cycling of battery B are shown on Fig.2, indicating that the rechargeab}e lithium battery made in accordance with the present invention has high capacity and is capable of rendering reliable service.
Following the cycling series, battery B was dismantled and the relevant component layers in a 100 cm2 area were weighed and analyzed. It was found that battery B contained 1.35 gram of graphite and 4.42 grams of lithium-cobalt oxide in the corresponding battery B cathode layer volume. Thus the ratio of the anode and cathode reversible capacities was found to be: mAh/g~ x Wn mAh/ga x We = 370 x 1.35 : 123 x 4.42 =
0.92, indicating a substantial increase in the energy output per weight of battery B when compared to battery A.
The speci~ic reversible capacity of ~attery B was found to ~e 64 mAh/gt, which also shows an increase in comparison to battery A.
The energy density of battery ~ was found to be 335 watt~hour/litre and 142 watt.hour/kg, compared to 272 watt.hour/litre and 116 watt.hour/kg of battery A.
A commercially available planar rechargeable lithium battery C, having lithium-manganese oxide as cathode active component and graphite as anode active component, was charged in the conventional manner by applying 4.2 volts to its external electrical leads at a ~u~ L level ~o~.L~olled to complete charging in a 24 hour period. A~ter charging battery CA 022l8709 l997-l0-2l C exhibited full battery voltage of 3.85 volts. Battery C had conventional anode film made of graphite of average particle size of 15~, containing 5 wt% polyvinylidene fluoride binder.
The electrolyte of battery C was porous polyethylene impregnated with ethylene car~onate-diethyl carbonate mixed in 1:1 ratio, containing LiPF6 in 1.0 mole concentration. It is known that conventional lithium-manganese oxide has specific reversible capacity of 142 mAh/g. The specific anode reversible capacity of the graphite utilized in the battery was 370 mAh/g. The specific reversible capacity of lithium battery C was found to be 57 mAh/gt; in the calculation gt was the sum total of the weig~ts o~ the anode active graphite, the cathode active lithium-manganese oxide and the impregnated microporous polyethylene electrolyte ~ ILised in a 100 cm2 area of battery C. The component layers of battery C were su~se~uently separated and analyzed. In a 100 cm2 segment of battery C the weight ratio of the anode active graphite to the cathode active lithium-manganese oxide in the anode and the cathode layers respectively, was found to be 4:15.7 or 1.35 g to 5.30 g. It was calculated that the value of the ratio of the anode capacity to the cathode capacity o~ battery C, that is: mAh~g~ x w~ divided by mAh/gc x wc = 370 x 1.35 : 142 x 5.30 = 0.66. This ratio is well ~elow 1, thus indicating that excess weight is carried in the cathode of battery C.
Battery D was made up of the same commercially available lithium-manganese oxide and graphite particles, utilizing the same amount of polyvinylidene fluoride binder and other additives in the anode and cathode respectively, as in battery C, however, the weight ratio of the anode active graphite particles to the cathode active lithium-manganese oxide was adjusted to 4:il.6. The electrolyte of battery D had the same composition as that of battery C. Thus the weight per unit area of battery D was lower than that of battery C. The ~ assembled lithium battery D was immersed in an electrolyte solution made o~ ethy~ene carbonate-diethyl carbonate, containing LiPF6 in 1 Molar concentration. A 1 mm thick lO0 mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A potential of 4.2 CA 022l8709 l997-l0-2l volts was applied between the lithium foil-third electrode and the anode of the lithium battery containing graphite particles as negative active material, the latter having negative polarity in the circuit. The current was applied until the anode of lithium battery D attained a potential of 2.75 volts against the lithium-manganese oxide bearing cathode of the lithium battery D. Battery D was then disconnected from the pre-charging potential and removed from the electrolyte.
Battery D was subsequently fitted with appropriate current collectors and electrical leads, and sealed in the conventional manner. Finally, battery D was charged in conventional manner to the full potential it was capable of attaining, i.e. 3.85 volts.
Battery D was subjected to 10 charging-discharging cycles and it was found to perform just as satisfactorily as battery C under similar cycling conditions.
Following lo cycles battery D was dismantled, the relevant component layers in a 100 cm2 area weighed and analyzed. It was found that battery D contained 1.35 grams of graphite particles and 3.92 grams of lithium-manganese oxide in the corresponding cathode layer volume of battery D. Thus the ratio of the anode and cathode reversible capacities was found to be: mAh/g~ x w~ : mAh/gO x WC - 370 x 1.35 : 142 x 3.92 = 0.90, indicating a substantial increase in the energy output per weight of battery D in ~o ~rison with battery C.
The specific reversible capacity of battery D was found to be 70 mAh/gt, which also shows an increase in comparison with battery C.
The energy density of ~attery D was found to be 345 watt.hour/liter and 146 watt.hour/kg, ~ pAred to 284 watt.hour/liter and 121 watt.hour/kg of battery C.
EXAMP~E 3 The capacity of rechargeable lithium battery E
constructed in a conventional manner of commercially available graphite and lithium-nickel oxide as the respective anode and cathode active material, and lithium ion conducting electrolyte made of polyethylene oxide containing ~iPF6 in 1 Molar concentration, was to be compared to the capacity of a rechargeable lithium battery cont~;ning similar components as battery E, made according to the present invention. The graphite utili~ed in the anode of the batteries was similar in quality and particle size as those in Examples 1 and 2. The lithium-nickel oxide-cont~i n; ng conventional battery E was fully charged and its composition and performance parameters noted in the similar manner as was done for batteries A, B, C, and D. The specific reversi~le capacity of lithium-nickel oxide is known to be 147 mAh/g. The weight ratio of graphite to lithium-nickel oxide in conventional battery E was 4:15.1, or 1.35 g graphite particles and 5.10 g lithium-nickel oxide were contained in a 100 cm2 area of battery E. The value of ratio of mAh/g~ x w~ : mAh/gc x wc = 370 x 1.35 : 147 x 5.10 was found to be 0.67 in the case of battery E. The specific reversible capacity of battery ~ was calculated as 59.5 mAh/gt, based on the total weights of the electrode active materials and the electrolyte contained in battery E.
Battery F was made up to contain the same type of commercially available electrode active and electrolyte materials as battery E, however, the weight ratio of the anode active carbon to the cathode active lithium-nickel oxide was in the case of battery F: 4:11.2, in all other respects battery F was similar to lithium battery E. The assembled lithium battery F was immersed in an electrolyte solution made of ethylene carbonate-diethyl carbonate, cont~ining LiPF6 in 1 Molar concentration. A 1 mm thick 100 mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A potential of ~ . 2 volts was applied between the lithium foil-third electrode and the anode of the lithium battery cont~;ning graphite particles as negative active material, the latter having negative polarity in the circuit. The current was applied until the anode of lithium battery F attained a potential of 2.7 volts against the lithium-nickel oxide ~earing cathode of lithium battery F; it was subse~uently disconnected from the pre-charging potential and removed from the electrolyte. The partially charged battery F was then fitted with a~pL~liate current collectors , CA 022l8709 l997-l0-2l ~ 18 ~
and electrical leads, and sealed in the usual manner.
Finally, battery F was charged in conventional manner to the full potential it was capable of att~ ;ng, i.e. 3.80 volts.
Battery F was subjected to 10 charging-discharging cycles and it was found to perform just as satisfactorily as battery E under similar cycling conditions.
Following 10 cycles battery F was dismantled, the relevant component layers in a 100 cm2 area weighed and analyzed. It was found that battery F contained 1.35 grams of graphite particles as anode active material and 3.78 grams of lithium-nickel oxide in the correspo~;ng cathode layer volume of battery F. ~hus the ratio of the anode and cathode reversible capacities was found to be:
mAh/~A X Wa : mAh/gc x wc = 370 x 1.35 : 147 x 3.78 = o.go, indicating a substantial increase in the energy output per weight of battery F in comparison with battery E.
The specific reversible capacity of battery F was found to be 73.1 mAh/gt, which also shows an increase in ~. -rison with battery E.
The energy density of battery F was found to be 350 watt.hour/liter and 151 watt.hour/kg, compared to 291 watt.hour/liter and 124 watt.hour/kg of battery E.
Results characterizing the lithium batteries discussed in Examples 1, 2 and 3 are shown in Table 1.
It has been shown that rechargeable lithium batteries which have been pre-charged in accordance with the present invention per~orm well, ~urthermore, these lithium batteries have reAllce~ weight compared to conventional rechargeable lithium batteries, and h~l-Cr~ have increased energy density per battery weight and volume.
The foregoing has described the principles, preferred ~;ments and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Instead, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present CA 02218709 l997-l0-2l ~ -- 19 --invention as defined by the following claims.
Battery¦Wt of Cathode Reactive Voltage Watt.hour Watt.hour s Material per 100 cm2 per litre per kg A LiXCoO2 6.08 g 4.05 272 116 B Lixcoo2 4.42 g 4.05 335 142 C LiyMnz04 5.30 g 3.85 284 121 D LiyMn20~ 3.92 g 3.85 345 146 E LixNio2 5.10 g 3.80 291 124 F LiXNio2 3.78 g 3.80 350 lS1
~;VI~:~TRT.~ CAPACIq~Y
FT~Tn OF lNv~NllON
This invention is related to rechargeable non-aqueous lithium batteries.
~Ar ~n~ N V . .- l lON
Most rechargeable lithium ion batteries have a negative electrode cont~inin~ elemental lithium, which is usually intercalated in some carho~c~sus substance, a positive el~uLLode bearing a chalcogenide, which is capable of incol~o aLing lithium ions in its structure, an electrolyte cont~;ning mobile lithium ions, located between the negative and positive ele~L-odes and, optionally, a separator. The positive electrode also contains lithium either as ions in~vl~ulated in the structure of the chalcogenide or as a lithium compound having ~ ociable lithium ions ready to be in~o~ yuL ated in the structure of the chalcogenide, a binder mixed with the chalcogenide, and optionally carbon added to increase the ~o~t~ctivity of the mixture. The chalcogenide in the positive electrode is usually a transition metal oxide but may also be a transition metal sulphide. In some instances the chalcogenide may be replaced with a suitable organic compound. The electrolyte is commonly a solid organic polymer or a non-aqueous li~uid, which has a lithium salt dissolved in 2g it or contains ~;~cociable lithium ions in some other form.
The electrolyte may also be a mi~;lu~oLous solid polymer which has been impregnated with an organic liquid cont~i ning a ~iccOciable lithium salt. The electrolyte which is non-conductive of ele~L~ s, provides ionic ~QC~e for the ~ 30 lithium ion~. Lithium ions move from the elemental lithium cont~ining negative electrode or anode to the transition metal oxide con~;ning positive electrode or cathode, on discharge of the battery. Lithium ions are moved from the cathode or positive electrode through the e~ectrolyte to the negative ele~L~ode in the charging step.
The common practice in constructing a rechargeable CA 022l8709 l997-l0-2l lithium battery is that the carbonaceous particles capable of intercalating lithium ions, added to serve as the cathode active material in the negative electrode of the battery often as compacted into a layer with the aid of an organic b~nder compound, are provided in the battery initially without having any lithium content. The lithium ions to be utilized in the battery are usually added as a component in the transition metal oxide capable of incorporating lithium ions in its structure in the positive electrode, and in the non-aqueous lithium bearing electrolyte. It is to be noted that this procedure is common in assembling planar, spirally wound and button shaped rechargeable lithium batteries. The assembled lithium battery is first charged by applying a voltage of about 4.5 volts between the electrodes of the lithium battery to move the lithium ions in the positive electrode for intercalation in the carbonaceous particles constituting the negative electrode. Most of the lithium added in the positive electrode can be moved by applying an electric charge, however, there is a limit of the lithium concentration within the transition metal oxide below which the oxide crystal structure is irreversibly changed. Furthermore, the first charging of the assembled battery is a slow process to be conducted under carefully controlled conditions.
The portion of the lithium ions moved out o~ the lithium-transition metal compound serving as the positive active material, by the imposed external potential for intercalation in the carbonaceous particles, will be permanently lodged in or attached to the surface of the carbonaceous particles serving as the negative active material, or will be appended to the interface between the carbonaceous particles and the non-aqueous electrolyte. The type of bonding by which a portion of the lithium ion becomes immobilizable is not known exactly; the bonding of the immobilizable lithium may be related to the structure of the carbonaceous particles or to the nature of the bonding of the mobile lithium ion in the electrolyte, or to the interaction between the lithium bearing electrolyte and the lithium intercalated in the carbonaceous particles or to similar features of the lithium battery, -however, such immobilizable portion of the lit~ium ion initially present in the rechargeable lithium battery is lost to subsequent charging-discharging process steps. The portion of the lithium ions that becomes non-mobilizable in subse~uent charging-discharging process steps usually constitutes 20-3~%
or even higher, of the total amount o~ lithium contained in the rechargeable lithium battery and is usually referred to as the irreversible capacity loss of the lithium ~attery. The non-mobilizable lithium portion, that is the iLl~ersible capacity, will thus be influ~n~ by many factors such as the sites available for the lithium ion for intercalation, i.e.
the nature of the carbon particles utilized, the nature and type of non-a~ueous lithium bearing electrolyte employed, as well as the kind o~ transition metal oxide utilized in the positive electrode. U.S. Patent 5,34~,670 issued to Norio Takami et al. on Au~ust 23, 1994, describes as the negative ac~ive material in a rechargeable lithium battery, graphite particles ob~ in a high temperature treatment step and of specific crystal structure, having advantageous properties with respect to irreversible capacity }oss. U.S. Patent 5,432,029 issued to Takehito Mitate et al~ on July 11, 1995, teaches the utilization of copper oxide attached to the graphite or similar carbonaceous particles incorporated in the negative ele~LLvde for diminishing the irreversible capacity loss in a rechargeable lithium battery. Domini~ue Guyomard et al. in U.S. Patent 5,422,203 issued on June 6, 1995, describe a lithium bearing electro7yte composition to be utilized for reducing the irreversible capacity loss in a lithium battery.
The above are merely listed as examples of attempts of defining the nature of irreversible capacity loss in a rechargeable lithium battery and methods f~or dimi ni~:h;rlg such irreversible capacity losses.
lt can be seen that the irreversible capacity loss of a rechargeable lithium battery may be related to both the negative active material and to the positive active material.
It is to be noted that the type of irreversibility associated with the negative electrode and its interface with the electrolyte is different from the i~Le~ersi~ility exhibited by _ CA 022l8709 l997-l0-2l the positive active material in the positive electrode, however, both kinds of irreversibilities are usually compensated by adding ~n excess amount of lithium containing transition metal compound to the battery. The excess lithium-transition metal compound is a necessary component of aconventional lithium battery but is not taking part in subsequent charging-recharging steps and may amount to 2S~ or more extra battery weight. The mobilizable lithium ion portion in the rechargeable lithium battery, related to the carbonaceous particles in the negative ele~LL~de, is usually referred to as the anode specific reversible capacity measured in milliampere-hours per gram of carbonaceous particles (mAh/g~), and that related to the transition metal compound in the positive electrode, is usually referred to as the cathode specific reversible capacity measured in milliampere-hours per gram of transition metal compound ~mAh/gc~.
It is also to be noted that the first charging step due to its prolonged nature and controlled conditions, is costly even if excess lithium is added in the form of extra lithium-transition metal compound. There are known methods forincorporating lithium in the carbonaceous particles prior to assembling the lithium battery comprising an electrolyte and negative and positive electrodes. ~.S. Patent 4,980,250 issued to Yuzuru Tak~h~ch; et al. on December 25, l990, describes carbon moulded articles made of carbon fibre or carbon powder having lithium introduced electrolytically in the moulded article prior to the incorporation of the carbon moulded article into a lithium battery. Cheng-Kuo Huang et al. in U.S. Patent 5,436,093, teach a method for introducing lithium into carbon particles from a li~uid electrolyte containing lithium ions by the application of more than one electrical charging steps. The carbon particles are carried by a nickel grid acting as the negatively charged electrode.
The positive electrode in the pretreatment process is at least one lithium sheet immersed in the electrolyte. The lithium containing carbon particles are withdrawn from the pretreating electrolyte and are- used subsequently as negative active material in a rechargeable lithium battery. There is, CA 022l8709 l997-l0-2l however, no clear indication that all or any portion of the lithium introduced by the above described methods contributes to the reversible anode capacity of the carbon particles in subseguent repeated charging-discharging of the obtained lithium battery, thereby eliminates the need for adding an extra amount of lithium ion con~in;ng transition metal compound to operate the rechargeable lithium ion battery satisfactorily, and hence provide a lighter lithium battery.
cU4~RY O~ ~l~ INVENTION
one of the objects of ~he present invention is to provide a rechargeable lithium battery which incorporates the non-mobilizable lithium ion portion in the negative electrode coupled to the non-aqueous electrolyte in the lithium battery in the stage prior to the final packaging of the rechargeable lithium battery and prior to the full charging of the battery, thereby avoiding having to add extra weight in the positive electrode.
Another object of the present invention is to reduce the length of time required in the first full charging step of the assembled lithium battery.
Yet another object of the present invention is to provide substantially all the mobilizable lithium ion portion as tha~
contained in the positive electrode and the dissociable lithium ion in the non-aqueous electrolyte of the resulting assembled lithium battery, and thereby obtaining a lithium battery having high energy density per unit weight.
A rechargeable lithium battery is described hereinbelow which has improved reversible capacity. The improved rechargeable lithium battery has a positive electrode comprising a transition metal compound capable of incorporating lithium ions in its structure as the positive active ~aterial in the cathode, the cathode having a cathode specific reversible capacity (mAh~gc)~ a negative electrode con~i n; ng carbonaceous particles capable of intercalating lithium ions as the negative active material in the anode, the anode having an anode specific reversible capacity (mAh/gn), as well as a non-aqueous electrolyte conductive of lithium ions, and a total amount of lithium ions distributed between the e~ectrodes and the non-agueous lithium ion bearing electrolyte. In the improved rechargeable lithium battery of the present invention the weight of the negative active material in the negative electrode (wn) and the weight of the positive active material in the positive electrode (wc) are adjusted such that the ratio of the anode specific reversible capacity multiplied by the weight of the negative active material contained in the rechargeable lithium battery to the cathode specific reversible capacity multiplied by the weight of the positive active material contained in the rechargeable lithium ion battery has a value between 0.85 and 1.15, that is mAh/g~ x w~ : mAh/gc x WC = 0.8~ - 1.15. The i,..~ved rechargeable lithium battery has an energy density in excess of 3?0 watt.hour/liter or 130 watt.hour/kg.
BRI~F D~rRTPTION 0~ THR DRAWINGS
Figure l is a schematic circuit diagram illustrating the initial transfer of lithium into the anode of the lithium battery according to the present in~ention.
Figure 2 shows the performance of a lithium battery of the present invention in repeated charging-discharging cycles.
n~T~TT,~ ~R~RTP$ION QF l~ PR~ EMBODIHENTS
As it has been briefly mentioned above, the energy density per unit weight of a rechargeable lithium battery is of significance in the commercial utilization of lithium batteries, in particular of planar lithium batteries. One of the desired features in lithium battery ~echnology is to reduce the weight of the battery components as ~uch as it is possible without loss of battery efficiency and ouL~uL.
3Q The transition metal compound utilized in rechargeable lithium batteries is usually a transition metal chalcogenide, most frequently a transition metal oxide but may also be a transition metal sulphide. The c ~-~ition of the transition metal oxide incorporating lithium ions in its structure depends on the type and kind of transition metal oxide utilized. For example, lithium-cobalt oxide has a ~l ~v~ition -W O 97/31401 PCT/C~97/00097 - 7 -of LixCoO2, where x is less than 1, similarly lithium bearing nickel oxide has a composition of LixNiO2. On the other hand, lithium bearing manganese oxide may be described as LiyMn2O4, where 0~y<2. The transition metal compound may also be an 5 oxide of chromium, copper, vanadium, Lu~ly~Len or alloys of the above mentioned metals with other metals, which are capable of incorporating lithium ions in their structure. The most often utilized transition me~al sulphide is TiS2, but other transition metal sulphides, such as iron sulphide, may also serve as cathode active materials. Some organic compounds which are capable of incorporating lithium ions reversibly and are also electronic conductors, may also be utilized in the positive electrode of a rechargeable lithium battery. In theory, ~irtually all the lithium ions incorporated in the structure of transition metal compound may be moved by an imposed direct potential, however, as mentioned above, below a certain lithium concentration that is characteristic of each transition metal compound, the crystal structure, in particular the lattice dimensions of the transition metal compound is likely to change irreversibly. Hence a certain portion of the lithium in the battery has to be retained in the positive ele~Lro~e being incorporated in an unavoidable extra cathode material wei~ht. The positive electrode may also contain fine carbon to increase the electrical conductivity of the el~Llode and a binder substance. The positive electrode is usually in contact with some form of a current collector.
The cathode or positive electrode of a rechargeable lithium battery will have a reversible capacity der~n~;ng on the nature of the cathode active material contained in the electrode and to a lesser degree, on the binder. The cathode specific reversible capacity is usually calculated per unit weight of the cafhode active material in the electrode and is expressed in milliampere-hours per gram (m~h/gG).
3~ The non-a~ueous electrolyte of a rechargeable lithium battery is usually either a solid polymer electrolyte contA;nin~ lithium in a ~iccociable form, or a porous polymer separator impregnated with an organic li~uid containing dissolved therein a llthium salt capable of dissociating.
For obvious reasons, the electrolyte is conductive only of ions and non-conductive of electrons. There are various ways to keep the electrolyte weight in the battery as low as possible, which is beyond the scope of the present invention.
The negative electrode o~ a rechargeable, or secondary lithium battery usually has some form of ~arbonaceous particles capable of intercalating lithium, as the negative active material. The carbonaceous particles most often utilized in a rechargeable lithium battery include graphite, glassy or pyrolytic carbon, petroleum coke, carbon fibres and any other form of carbon particles that can intercalate lithium under normal circumst~c~. The preferred particle size of the carbonaceous particles is less than 60~ but ~reater than 5~. It is known that the lithium intercalated in carbon has the general formula of LiC6 but other lithium to carbon ratios have also been recorded. It is also known that a portion of the lithium subse~uent to the first introduct~on of lithium into the carhon~ceous particles, that is in the initial lithium charging step of a lithium battery, is irreversibly retained in the carbon structure. As discussed above, it is not known exactly whether the irreversibly bonded lithium attaches itself to some structural elements of the carbon or to the surface of the particles, or is located on the interface between the carbonaceous particles and the lithium ion con~llcting electrolyte. It has been observed that such irreversible capacity loss may depend on the type and history of the carbonaceous particles, on the binder substance utilized, on the nature of the electrolyte composition and so forth. Whatever is the reason, a portion of the transferred lithium is lost for subsequent battery charging~ çh~ging process steps. As mentioned hereinabove, in conventional rechargeab}e lithium batteries the irreversibly bonded lithium is compensated by an extra amount of lithium-transition metal compound ~e~ in the cathode, thus increasing the total weight of the battery.
The anode or negative ele~L~vde o~ a rechargeable lithium battery will have a reversible capacity der~nd; ng on the -PCT/C~97/00097 g na~ure of the cathode active material, that is on the type of carbonaceous particles contained in the anode and to a limited degree, on the binder. The anode specific reversible capacity is usually calculated per unit weight of the anode active ma~erial present in the electrode and is expressed in milliampere-hours per gram (mA~/g,).
It is known to introduce lithium into the carbonaceous particles by various methods prior to the carbonaceous material ~eing incorporated in the anode of the lithium battery, however it is believed, these methods have not been successful in eliminating an additional irreversible capacity loss that occurs during the first charging of the lithium battery. In other words, an extra amount of lithium-transitional metal compound is still needed over and above the reversibly incorporated lithium requirement of the carbonaceous particles in the anode.
It has now been surprisingly found that if the lithium is added electrolytically during the first chargin~ of the assembled rechargeable lithium ~attery in such a manner that the lithium transferred from the positive electrode for initially charginq the anode, is replaced from a third lithium electrode, no extra amount of lithium-transition metal compound is required to compensate for the irreversible capacity loss in the ~no~e. The im~ved rechargeable lithium battery of the present invention undergoes a first charging or pre-charging step of the battery in an electrical circuit which incorporates a third lithium cont~;ning electrode, which is most often an elemental lithium bearing electrode. The third ele~L-ode is separated from the lithium-transition metal compound cont~;n;ng cathode by another non-aqueous lithium ion containing electrolyte but is electrically ~ionically~ in contact with it. In practice, a positive potential is applied to the third, usually elemental lithium cont~;n;ng electrode, thereby forcing lithium ions to enter into the electrolyte separating the third electrode from the lithium-transition metal ~l~oul,d cont~;n;ng cathode of the lithium battery. The arriving lithium ions,- in turn, force an equivalent amount of lithium ions to leave the cathode to enter by way of the -CA 022l8709 l997-l0-2l electrolyte within the lithium battery into the anode to be intercalated by the carbonaceous particles in the negative electrode. As usual in the charging step, the anode carries a negative potential, thus closing the circuit. The pre-charging is conducted at the usual charging potential of alithium ~attery, that is at about 4.5 volts at the conventionally required current density for an appropriate length of time. The assembled pre-charged lithium battery is disconnected from the third e~ectrode and the additional or temporary electrolyte, and is subse~uently sealed and packaged with appropriate current collectors and electric leads in the usual manner.
The temporary electrolyte in contact with the third ele~Llode cont~;n;ng a source of lithium ions may have the same composition as the electrolyte of the assembled rechargeable lithium battery, or may be a different electrolyte such as an organic liquid having a lithium salt dissolved therein. The third ele~L~ode may ~e a lithium foil immersed in the organic li~uid or an alloy of lithium or may be another lithium ion con~; n; n~ f - , - und. Any convenient lithium source that is capable of providing lithium ions to the positive electrode of the rechargeable lithium ~attery and can be incorporated in an electrical circuit, is suitable for facilitating the pre-charging of the rechargeable lithium battery in accordance with the present invention. Fig.1 represents a schematic diagram of the electrical circuit of the pre-charging process step of the battery, where 2 is the negative electrode bearing carho~r~ous particles which do not contain any lithium before the pre-charging process step, 4 represents the lithium battery electrolyte and 6 is the lithium-transition metal com~oulid con~in;~g positive electrode. The positive electrode is in contact with the pre-charging temporary electrolyte 8, which in turn is in electrolytic contac~ with the third, usually but not nec~rily, elemental lithium cont~;n;ng electrode 10. In the preferred embo~i --L the third electrode is lithium metal or an elemental lithium cont~;n;ng alloy. Reference numeral 12 represents the external potential source, providing the CA 02218709 l997-l0-2l W O 97/31401 ~ PCT/CAg7/00097 - current for the pre-charging process step of the rechargeable lithium battery. The broken line 14 around the schematically drawn rechargeab~e lithium battery components represents conventional sealers, ~r L ~"t collectors and electrical leads which encase the rechargeable lithium battery subsequent to the pre-charging step.
For the sake of clarity, in the present description pre-charging of the lithium battery is understood to mean the first transfer of lithium ions to be intercalated in the carbonaceous particles of the anode or negative electrode, by means of applying a positive electrical potential to a third electrode which acts as a source of lithium ions. In the pre-charging step the third electrode is connected by means of a non-a~ueous electrolyte referred to as temporary electrolyte, to the positive electrode of the lithium battery. The temporary electro~yte is disconnected from the lithium battery after the pre-charging has taken place.
It is noted that the rechargeable lithium battery may not be fully charged in the pre-charging step and additional 20' charging of the lithium battery may still be re~uired after the rechargeable lithium battery has been separated from the third electrode and its electrolyte, sealed and packaged in the conventional manner. Whether the battery i5 fully charged or only partially charged in the pre-charging step, depends on the composition of the cathode active material and may also be dictated by other aspects of convenience. Optionally, the fully pre-charged lithium battery is allowed to discharge to attain its conventional low voltage level and is subsequently packaged and sealed.
one of the important features of the present invention i5 that the bonding between the electrolyte, shown as 4 on Fig.l, and the lithium bearing carbonaceous partic-e-cont~;n;ng anode 2 formed in the pre-charging step, is not disL~.bed or broken in the subsequent sealing and packaging of the rechargeable lithium battery. In other words, the lithium is transferred through the same electrolyte-anode interface in the pre-charging step as in subsequent charging-discharging steps taking place in utilizing the rechargeable lithium battery of the present inventio~.
The a~ove described pre-charging process may ~e applied to planar, spirally wound and button-shaped rechargeable lithium batteries.
The specific reversible capacity of a rechargeable lithium battery refers to the total reversible capacity of the assembled lithium ~attery and is expressed in milliampere-hours per the total weight of the active components of the lithium battery, that is the sum of the weights of the anode active material, the cathode active material and the non-aqueous electrolyte comprised in the lithium battery ~mAh/gt).
The reversible capacity of the rechargeable lithium battery made in accordance with the present invention is usually not much lower than the value of the lesser of the reversible capacities of the electrodes. It should be noted that in practical applications the values of the electrode reversible capacities within a rechargeable lithium battery are similar to one another.
The present invention will now be illustrated by working examples.
~XAMPLE 1 A commercially available planar rechargeable lithium battery A, having lithium-cobalt oxide as cathode active component and graphite as anode active component, was charged in the conventional manner by applying 4.2 volts to its external electrical leads at a current level controlled to complete charging in a 24 hour period. After charging battery A exhibited full battery voltage o~ 4.05 volts. Battery A had conventional anode film made of graphite of average particle size of 15~, cont~;ning 5 wt% polyvinylidene fluoride binder.
The electrolyte of battery A was porous polyethylene impregnated with ethylene carbonate-diethyl carbonate mixed in 1:1 ratio, cont~; n; ng LiPF6 in 1.0 mole concentration. It is known that conventional lithium-cobalt oxide has specific reversible capac~ty of 123 mAh/g. The specific anode reversible capacity of-the graphite utilized in the ~attery is 370 mAh/g. The reversible capacity of battery A was measured W O 97t31401 PCT/CA9710~097 - 13 -in the usual manner and the component layers of battery A were subse~uently separated and analyzed. The specific reversible capacity of lithium battery A was then obtained as 52 mAh/gt;
in the calculation gt was the sum total of the weights o~ the anode active graphite, cathode active lithium-co~alt oxide and the impregnated microporous polyethylene electrolyte comprised in a 100 cm2 area of battery A. The 100 cm2 segment of battery A was fo~nd to contain 1.35 g anode active graphite particles and 6.08 g cathode active lithium-cobalt oxide, that is the weight ratio of graphite to lithium-cobalt oxide in the anode and cathode layers respectively, was found to be 4:18. It was calculated that the value of the ratio of the anode capacity to the cathode capacity of battery A, that is: mAh/g~ x w~
divided by mAh/gc x wc = 370 x 1.3~ : 123 x 6.08 = O.67. This ratio is well below 1, thus indicating that excess weight is carried in the cathode.
Battery B was made up of the same commercially available lithium-cobalt oxide and graphite particles, utilizing the same amount of polyvinylidene fluoride binder and other additives in the anode and cathode, respectively, as in battery A, however, the weight ratio of the anode active graphite particles to the cathode active lithium-cobalt oxide was 4:13.2. The electrolyte of battery B had the same composition as that of battery A, but the weight per unit area 2~ of battery B was lower than that of battery A. The assemblad lithium battery B was immersed in an electrolyte solution made of ethylene carbonate-diethyl carbonate, containing LiP~6 in 1 Molar concentration. A 1 mm thick lOo mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A direct potential of 4.2 volts was applied between the lithium foil-third electrode and the anode of lithium battery B con~;ning graphite particles as negative active material, the latter having negative polarity in the circuit. The direct current was applied until the anode of lithium battery B attained a potential of 2.9 volts against the lithium-cobalt oxide bearing cathode of lithium battery B.
Battery B was then disconnected from the pre-charging direct potential and removed from the temporary electrolyte. Battery CA 022l8709 l997-l0-2l _ - 14 -B was subsequently fitted with appropriate current collectors and electrical leads, and sealed in the conventional manner.
Battery B was then charged to the full potential value it was capable of at~;n;ng, i.e. 4.05 volts, in conventional manner.
Battery B was subjected to several charging-discharging cycles and it was found to perform 3ust as satisfactorily as battery A under similar cycling conditions.
In a subse~uent series of tests the capacity of battery ~ was first measured in charging and discharging cycles at 25 mA current, which was then followed by charging and discharging cycles conducted at 40 mA current. The reversible capacities manifested in the cycling of battery B are shown on Fig.2, indicating that the rechargeab}e lithium battery made in accordance with the present invention has high capacity and is capable of rendering reliable service.
Following the cycling series, battery B was dismantled and the relevant component layers in a 100 cm2 area were weighed and analyzed. It was found that battery B contained 1.35 gram of graphite and 4.42 grams of lithium-cobalt oxide in the corresponding battery B cathode layer volume. Thus the ratio of the anode and cathode reversible capacities was found to be: mAh/g~ x Wn mAh/ga x We = 370 x 1.35 : 123 x 4.42 =
0.92, indicating a substantial increase in the energy output per weight of battery B when compared to battery A.
The speci~ic reversible capacity of ~attery B was found to ~e 64 mAh/gt, which also shows an increase in comparison to battery A.
The energy density of battery ~ was found to be 335 watt~hour/litre and 142 watt.hour/kg, compared to 272 watt.hour/litre and 116 watt.hour/kg of battery A.
A commercially available planar rechargeable lithium battery C, having lithium-manganese oxide as cathode active component and graphite as anode active component, was charged in the conventional manner by applying 4.2 volts to its external electrical leads at a ~u~ L level ~o~.L~olled to complete charging in a 24 hour period. A~ter charging battery CA 022l8709 l997-l0-2l C exhibited full battery voltage of 3.85 volts. Battery C had conventional anode film made of graphite of average particle size of 15~, containing 5 wt% polyvinylidene fluoride binder.
The electrolyte of battery C was porous polyethylene impregnated with ethylene car~onate-diethyl carbonate mixed in 1:1 ratio, containing LiPF6 in 1.0 mole concentration. It is known that conventional lithium-manganese oxide has specific reversible capacity of 142 mAh/g. The specific anode reversible capacity of the graphite utilized in the battery was 370 mAh/g. The specific reversible capacity of lithium battery C was found to be 57 mAh/gt; in the calculation gt was the sum total of the weig~ts o~ the anode active graphite, the cathode active lithium-manganese oxide and the impregnated microporous polyethylene electrolyte ~ ILised in a 100 cm2 area of battery C. The component layers of battery C were su~se~uently separated and analyzed. In a 100 cm2 segment of battery C the weight ratio of the anode active graphite to the cathode active lithium-manganese oxide in the anode and the cathode layers respectively, was found to be 4:15.7 or 1.35 g to 5.30 g. It was calculated that the value of the ratio of the anode capacity to the cathode capacity o~ battery C, that is: mAh~g~ x w~ divided by mAh/gc x wc = 370 x 1.35 : 142 x 5.30 = 0.66. This ratio is well ~elow 1, thus indicating that excess weight is carried in the cathode of battery C.
Battery D was made up of the same commercially available lithium-manganese oxide and graphite particles, utilizing the same amount of polyvinylidene fluoride binder and other additives in the anode and cathode respectively, as in battery C, however, the weight ratio of the anode active graphite particles to the cathode active lithium-manganese oxide was adjusted to 4:il.6. The electrolyte of battery D had the same composition as that of battery C. Thus the weight per unit area of battery D was lower than that of battery C. The ~ assembled lithium battery D was immersed in an electrolyte solution made o~ ethy~ene carbonate-diethyl carbonate, containing LiPF6 in 1 Molar concentration. A 1 mm thick lO0 mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A potential of 4.2 CA 022l8709 l997-l0-2l volts was applied between the lithium foil-third electrode and the anode of the lithium battery containing graphite particles as negative active material, the latter having negative polarity in the circuit. The current was applied until the anode of lithium battery D attained a potential of 2.75 volts against the lithium-manganese oxide bearing cathode of the lithium battery D. Battery D was then disconnected from the pre-charging potential and removed from the electrolyte.
Battery D was subsequently fitted with appropriate current collectors and electrical leads, and sealed in the conventional manner. Finally, battery D was charged in conventional manner to the full potential it was capable of attaining, i.e. 3.85 volts.
Battery D was subjected to 10 charging-discharging cycles and it was found to perform just as satisfactorily as battery C under similar cycling conditions.
Following lo cycles battery D was dismantled, the relevant component layers in a 100 cm2 area weighed and analyzed. It was found that battery D contained 1.35 grams of graphite particles and 3.92 grams of lithium-manganese oxide in the corresponding cathode layer volume of battery D. Thus the ratio of the anode and cathode reversible capacities was found to be: mAh/g~ x w~ : mAh/gO x WC - 370 x 1.35 : 142 x 3.92 = 0.90, indicating a substantial increase in the energy output per weight of battery D in ~o ~rison with battery C.
The specific reversible capacity of battery D was found to be 70 mAh/gt, which also shows an increase in comparison with battery C.
The energy density of ~attery D was found to be 345 watt.hour/liter and 146 watt.hour/kg, ~ pAred to 284 watt.hour/liter and 121 watt.hour/kg of battery C.
EXAMP~E 3 The capacity of rechargeable lithium battery E
constructed in a conventional manner of commercially available graphite and lithium-nickel oxide as the respective anode and cathode active material, and lithium ion conducting electrolyte made of polyethylene oxide containing ~iPF6 in 1 Molar concentration, was to be compared to the capacity of a rechargeable lithium battery cont~;ning similar components as battery E, made according to the present invention. The graphite utili~ed in the anode of the batteries was similar in quality and particle size as those in Examples 1 and 2. The lithium-nickel oxide-cont~i n; ng conventional battery E was fully charged and its composition and performance parameters noted in the similar manner as was done for batteries A, B, C, and D. The specific reversi~le capacity of lithium-nickel oxide is known to be 147 mAh/g. The weight ratio of graphite to lithium-nickel oxide in conventional battery E was 4:15.1, or 1.35 g graphite particles and 5.10 g lithium-nickel oxide were contained in a 100 cm2 area of battery E. The value of ratio of mAh/g~ x w~ : mAh/gc x wc = 370 x 1.35 : 147 x 5.10 was found to be 0.67 in the case of battery E. The specific reversible capacity of battery ~ was calculated as 59.5 mAh/gt, based on the total weights of the electrode active materials and the electrolyte contained in battery E.
Battery F was made up to contain the same type of commercially available electrode active and electrolyte materials as battery E, however, the weight ratio of the anode active carbon to the cathode active lithium-nickel oxide was in the case of battery F: 4:11.2, in all other respects battery F was similar to lithium battery E. The assembled lithium battery F was immersed in an electrolyte solution made of ethylene carbonate-diethyl carbonate, cont~ining LiPF6 in 1 Molar concentration. A 1 mm thick 100 mm wide lithium foil mounted on a stainless steel carrier was also immersed in the electrolyte solution. A potential of ~ . 2 volts was applied between the lithium foil-third electrode and the anode of the lithium battery cont~;ning graphite particles as negative active material, the latter having negative polarity in the circuit. The current was applied until the anode of lithium battery F attained a potential of 2.7 volts against the lithium-nickel oxide ~earing cathode of lithium battery F; it was subse~uently disconnected from the pre-charging potential and removed from the electrolyte. The partially charged battery F was then fitted with a~pL~liate current collectors , CA 022l8709 l997-l0-2l ~ 18 ~
and electrical leads, and sealed in the usual manner.
Finally, battery F was charged in conventional manner to the full potential it was capable of att~ ;ng, i.e. 3.80 volts.
Battery F was subjected to 10 charging-discharging cycles and it was found to perform just as satisfactorily as battery E under similar cycling conditions.
Following 10 cycles battery F was dismantled, the relevant component layers in a 100 cm2 area weighed and analyzed. It was found that battery F contained 1.35 grams of graphite particles as anode active material and 3.78 grams of lithium-nickel oxide in the correspo~;ng cathode layer volume of battery F. ~hus the ratio of the anode and cathode reversible capacities was found to be:
mAh/~A X Wa : mAh/gc x wc = 370 x 1.35 : 147 x 3.78 = o.go, indicating a substantial increase in the energy output per weight of battery F in comparison with battery E.
The specific reversible capacity of battery F was found to be 73.1 mAh/gt, which also shows an increase in ~. -rison with battery E.
The energy density of battery F was found to be 350 watt.hour/liter and 151 watt.hour/kg, compared to 291 watt.hour/liter and 124 watt.hour/kg of battery E.
Results characterizing the lithium batteries discussed in Examples 1, 2 and 3 are shown in Table 1.
It has been shown that rechargeable lithium batteries which have been pre-charged in accordance with the present invention per~orm well, ~urthermore, these lithium batteries have reAllce~ weight compared to conventional rechargeable lithium batteries, and h~l-Cr~ have increased energy density per battery weight and volume.
The foregoing has described the principles, preferred ~;ments and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Instead, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present CA 02218709 l997-l0-2l ~ -- 19 --invention as defined by the following claims.
Battery¦Wt of Cathode Reactive Voltage Watt.hour Watt.hour s Material per 100 cm2 per litre per kg A LiXCoO2 6.08 g 4.05 272 116 B Lixcoo2 4.42 g 4.05 335 142 C LiyMnz04 5.30 g 3.85 284 121 D LiyMn20~ 3.92 g 3.85 345 146 E LixNio2 5.10 g 3.80 291 124 F LiXNio2 3.78 g 3.80 350 lS1
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an improved rechargeable lithium battery, said rechargeable lithium battery having a positive electrode containing a transition metal compound capable of incorporating lithium ions in its structure as the positive active material, a negative electrode containing carbonaceous particles capable of intercalating lithium ions as the negative active material, a non-aqueous electrolyte conductive of lithium ions, and a total amount of lithium ions distributed between the electrodes and the non-aqueous lithium ion bearing electrolyte, said rechargeable lithium battery having a capacity measured in milliampere-hours per gram weight of battery(mAh/g t), an anode specific reversible capacity (mAh/g a) and a cathode specific reversible capacity (mAh/g c), the improvement comprising that the weight of the negative active material in said negative electrode (w a) and the weight of the positive active material in said positive electrode (w c) are adjusted such that the value of the ratio, denoted by n, of said anode specific reversible capacity multiplied by said weight of the negative active material contained in said rechargeable lithium battery, to said cathode specific reversible capacity multiplied by said weight of the positive active material contained in said rechargeable lithium ion battery, is expressed as mAh/g a x w a : mAh/g c x w c = 0.85< n <1.15, and that the weight of the negative active material in the negative electrode (w a) is adjusted by introducing a portion of said total amount of lithium ions in said rechargeable lithium battery in an assembled state prior to packaging and sealing said battery;
thereby providing a rechargeable lithium battery having an energy density of at least 320 watt.hour/liter.
thereby providing a rechargeable lithium battery having an energy density of at least 320 watt.hour/liter.
2. A rechargeable lithium battery as claimed in claim 1, wherein said rechargeable lithium battery is a planar battery having energy density of at least 130 watt.hour/kg.
3. A rechargeable lithium battery as claimed in claim 1, wherein said portion of said total amount of lithium ions in said rechargeable lithium battery is introduced in said carbonaceous particles capable of intercalating lithium ions subsequent to assembling said positive electrode, said negative electrode and said non-aqueous electrolyte conductive of lithium ions comprised in said rechargeable lithium battery, but prior to packaging and sealing said rechargeable lithium battery.
4. A rechargeable lithium battery as claimed in claim 3, wherein said portion of said total amount of lithium ions is introduced in said carbonaceous particles by electrolytic means utilizing a third electrode comprising one of the group consisting of elemental lithium, a lithium alloy and a lithium containing compound.
5. A rechargeable lithium battery as claimed in claim 1, wherein the transition metal compound capable of incorporating lithium ions in its structure is a transition metal chalcogenide.
6. A rechargeable lithium battery as claimed in claim 5, wherein the transition metal chalcogenide capable of incorporating lithium ions in its structure is selected from the group consisting of: manganese oxide, cobalt oxide, nickel oxide, vanadium oxide, chromium oxide, copper oxide, tungsten oxide and intimately mixed oxidic compounds thereof, titanium sulphide and iron sulphide.
7. A rechargeable lithium battery as claimed in claim 1, wherein the non-aqueous electrolyte conductive of lithium ions is a solid polymer electrolyte containing lithium ions.
8. A rechargeable lithium battery as claimed in claim 1, wherein the non-aqueous electrolyte conductive of lithium ions is a microporous polymer impregnated with an organic liquid containig lithium ions.
9. A rechargeable lithium battery as claimed in claim 1, wherein the carbonaceous particles capable of intercalating lithium ions are selected from the group consisting of:
petroleum coke, glassy carbon particles, graphite particles and carbon particles, said carbonaceous particles having cross-sectional diameter of less than 60µm.
petroleum coke, glassy carbon particles, graphite particles and carbon particles, said carbonaceous particles having cross-sectional diameter of less than 60µm.
10. A rechargeable lithium battery as claimed in claim 1, having cobalt oxide as a transition metal compound capable of incorporating lithium ions in its structure, said cobalt oxide having cathode specific reversible capacity in the range of 123~5 mAh/g.
11. A rechargeable lithium battery as claimed in claim 1, having manganese oxide as a transition metal compound capable of incorporating lithium ions in its structure, said manganese oxide having cathode specific reversible capacity in the range of 142~5 mAh/g.
12. A rechargeable lithium battery as claimed in claim 1, having nickel oxide as a transition metal compound capable of incorporating lithium ions in its structure, said nickel oxide having cathode specific reversible capacity in the range of 147~5 mAh/g.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/604,220 | 1996-02-22 | ||
| US08/604,220 US5721067A (en) | 1996-02-22 | 1996-02-22 | Rechargeable lithium battery having improved reversible capacity |
| PCT/CA1997/000097 WO1997031401A1 (en) | 1996-02-22 | 1997-02-12 | Rechargeable lithium battery having improved reversible capacity |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2218709A1 CA2218709A1 (en) | 1997-08-28 |
| CA2218709C true CA2218709C (en) | 2001-04-17 |
Family
ID=24418700
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002218709A Expired - Lifetime CA2218709C (en) | 1996-02-22 | 1997-02-12 | Rechargeable lithium battery having improved reversible capacity |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US5721067A (en) |
| EP (1) | EP0845158B1 (en) |
| JP (1) | JP3206604B2 (en) |
| KR (1) | KR100320999B1 (en) |
| CN (1) | CN1114236C (en) |
| BR (1) | BR9702193A (en) |
| CA (1) | CA2218709C (en) |
| DE (1) | DE69707622T2 (en) |
| WO (1) | WO1997031401A1 (en) |
Families Citing this family (81)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996027910A1 (en) * | 1995-03-06 | 1996-09-12 | Fuji Photo Film Co., Ltd. | Nonaqueous secondary cell |
| IT1283968B1 (en) * | 1996-03-29 | 1998-05-07 | Consiglio Nazionale Ricerche | RECHARGEABLE LITHIUM OR LITHIUM-ION BATTERY ABLE TO SUSTAIN PROLONGED CYCLING. |
| US6514638B2 (en) * | 1997-05-27 | 2003-02-04 | Tdk Corporation | Non-aqueous electrolyte secondary battery including positive and negative electrodes |
| DE19845668A1 (en) * | 1998-10-05 | 2000-04-06 | Varta Batterie | Secondary lithium-ion cell |
| CA2373904C (en) * | 2000-03-07 | 2010-01-26 | Teijin Limited | Lithium ion secondary battery, separator, battery pack and charging method |
| US6881438B2 (en) * | 2000-03-07 | 2005-04-19 | Teijin Limited | Process for production of composite porous film |
| US7094497B2 (en) * | 2000-03-07 | 2006-08-22 | Teijin Limited | Separator for lithium ion secondary battery |
| WO2002082574A1 (en) * | 2001-03-30 | 2002-10-17 | Sony Corporation | Nonaqueous electrolytic cell and its manufacturing method, and positive electrode active material and its manufacturing method |
| CN1205689C (en) * | 2001-09-28 | 2005-06-08 | 任晓平 | Secondary lithium ion battery or battery pack, its protective circuit and electronic device |
| US7993773B2 (en) | 2002-08-09 | 2011-08-09 | Infinite Power Solutions, Inc. | Electrochemical apparatus with barrier layer protected substrate |
| US8404376B2 (en) | 2002-08-09 | 2013-03-26 | Infinite Power Solutions, Inc. | Metal film encapsulation |
| US20070264564A1 (en) * | 2006-03-16 | 2007-11-15 | Infinite Power Solutions, Inc. | Thin film battery on an integrated circuit or circuit board and method thereof |
| US8445130B2 (en) * | 2002-08-09 | 2013-05-21 | Infinite Power Solutions, Inc. | Hybrid thin-film battery |
| US8431264B2 (en) * | 2002-08-09 | 2013-04-30 | Infinite Power Solutions, Inc. | Hybrid thin-film battery |
| US8021778B2 (en) | 2002-08-09 | 2011-09-20 | Infinite Power Solutions, Inc. | Electrochemical apparatus with barrier layer protected substrate |
| US8236443B2 (en) * | 2002-08-09 | 2012-08-07 | Infinite Power Solutions, Inc. | Metal film encapsulation |
| US8394522B2 (en) | 2002-08-09 | 2013-03-12 | Infinite Power Solutions, Inc. | Robust metal film encapsulation |
| CN1323462C (en) * | 2002-11-05 | 2007-06-27 | 株式会社杰士汤浅 | Charging method of non-aqueous electrolyte secondary battery |
| AU2003292781A1 (en) * | 2002-12-26 | 2004-07-22 | Fuji Jukogyo Kabushiki Kaisha | Electrical storage device and method for manufacturing electrical storage device |
| US8728285B2 (en) * | 2003-05-23 | 2014-05-20 | Demaray, Llc | Transparent conductive oxides |
| KR101127370B1 (en) | 2004-12-08 | 2012-03-29 | 인피니트 파워 솔루션스, 인크. | Deposition of licoo2 |
| US7959769B2 (en) * | 2004-12-08 | 2011-06-14 | Infinite Power Solutions, Inc. | Deposition of LiCoO2 |
| WO2006108302A1 (en) * | 2005-04-15 | 2006-10-19 | Avestor Limited Partnership | LITHIUM RECHARGEABLE CELL HAVING AN EXCESS OF LiFePO4 BASED CATHODE RELATIVE TO A Li4Ti5O12 BASED ANODE |
| JP4963186B2 (en) * | 2006-03-31 | 2012-06-27 | パナソニック株式会社 | Nonaqueous electrolyte secondary battery |
| US7846571B2 (en) | 2006-06-28 | 2010-12-07 | Robert Bosch Gmbh | Lithium reservoir system and method for rechargeable lithium ion batteries |
| KR100977965B1 (en) * | 2006-08-25 | 2010-08-24 | 주식회사 엘지화학 | Highly reversible electrode active material capable of inserting lithium, a manufacturing method thereof, an electrode comprising the same, and a secondary battery |
| US20080067972A1 (en) | 2006-09-15 | 2008-03-20 | Norio Takami | Power supply system and motor car |
| WO2008036283A2 (en) * | 2006-09-19 | 2008-03-27 | Leonard Terrence W | Heated glove |
| CN101523571A (en) * | 2006-09-29 | 2009-09-02 | 无穷动力解决方案股份有限公司 | Masking and material confinement of a battery layer deposited on a flexible substrate |
| GB2443852B (en) * | 2006-10-25 | 2008-12-17 | Oxis Energy Ltd | A Lithium-Sulphur Battery with a High Specific Energy and a Method of Operating same |
| EP2076936B1 (en) | 2006-10-25 | 2018-07-18 | Oxis Energy Limited | A lithium-sulphur battery with a high specific energy and a method of operating same |
| US8197781B2 (en) * | 2006-11-07 | 2012-06-12 | Infinite Power Solutions, Inc. | Sputtering target of Li3PO4 and method for producing same |
| JP4779985B2 (en) * | 2007-02-07 | 2011-09-28 | トヨタ自動車株式会社 | Pre-doping lithium ion battery and method for producing lithium ion battery |
| US8313866B2 (en) * | 2007-05-22 | 2012-11-20 | Tiax Llc | Non-aqueous electrolytes and electrochemical devices including the same |
| US8268488B2 (en) | 2007-12-21 | 2012-09-18 | Infinite Power Solutions, Inc. | Thin film electrolyte for thin film batteries |
| CN101903560B (en) * | 2007-12-21 | 2014-08-06 | 无穷动力解决方案股份有限公司 | Method for sputter targets for electrolyte films |
| US8518581B2 (en) | 2008-01-11 | 2013-08-27 | Inifinite Power Solutions, Inc. | Thin film encapsulation for thin film batteries and other devices |
| DE102008008483B4 (en) | 2008-02-08 | 2021-08-05 | Volkswagen Ag | Solid polymer electrolyte material, solid polymer electrolyte sheet and methods for their production and electrochemical battery device using such a sheet |
| WO2009124191A2 (en) * | 2008-04-02 | 2009-10-08 | Infinite Power Solutions, Inc. | Passive over/under voltage control and protection for energy storage devices associated with energy harvesting |
| JP2012500610A (en) | 2008-08-11 | 2012-01-05 | インフィニット パワー ソリューションズ， インコーポレイテッド | Energy device with integrated collector surface and method for electromagnetic energy acquisition |
| CN102150185B (en) * | 2008-09-12 | 2014-05-28 | 无穷动力解决方案股份有限公司 | Energy device with integral conductive surface for data communication via electromagnetic energy and method thereof |
| WO2010042594A1 (en) * | 2008-10-08 | 2010-04-15 | Infinite Power Solutions, Inc. | Environmentally-powered wireless sensor module |
| US8158282B2 (en) * | 2008-11-13 | 2012-04-17 | Nanotek Instruments, Inc. | Method of producing prelithiated anodes for secondary lithium ion batteries |
| US8241793B2 (en) * | 2009-01-02 | 2012-08-14 | Nanotek Instruments, Inc. | Secondary lithium ion battery containing a prelithiated anode |
| CN102439778B (en) * | 2009-05-20 | 2016-02-10 | 萨普拉斯特研究有限责任公司 | For electrochemical device to be integrated within fixation means or on method |
| CN102576828B (en) | 2009-09-01 | 2016-04-20 | 萨普拉斯特研究有限责任公司 | Printed circuit board with integrated thin-film battery |
| KR20120128125A (en) | 2009-11-03 | 2012-11-26 | 엔비아 시스템즈 인코포레이티드 | High capacity anode materials for lithium ion batteries |
| EP2577777B1 (en) | 2010-06-07 | 2016-12-28 | Sapurast Research LLC | Rechargeable, high-density electrochemical device |
| CN102456927B (en) * | 2010-10-30 | 2014-05-28 | 比亚迪股份有限公司 | Method for manufacturing lithium ion battery |
| US9166222B2 (en) * | 2010-11-02 | 2015-10-20 | Envia Systems, Inc. | Lithium ion batteries with supplemental lithium |
| DE102010044008A1 (en) * | 2010-11-16 | 2012-05-16 | Varta Micro Innovation Gmbh | Lithium-ion cell with improved aging behavior |
| CN102487151B (en) * | 2010-12-02 | 2014-10-08 | 比亚迪股份有限公司 | Lithium ion secondary battery |
| CN103493258A (en) * | 2011-02-25 | 2014-01-01 | 应用材料公司 | Lithium ion cell design apparatus and method |
| US9601228B2 (en) | 2011-05-16 | 2017-03-21 | Envia Systems, Inc. | Silicon oxide based high capacity anode materials for lithium ion batteries |
| US9385397B2 (en) | 2011-08-19 | 2016-07-05 | Nanotek Instruments, Inc. | Prelithiated current collector and secondary lithium cells containing same |
| CN104081573B (en) | 2011-12-01 | 2018-01-16 | 那诺思卡乐康母庞特公司 | The method of alkalization anode |
| US10128491B2 (en) | 2011-12-01 | 2018-11-13 | Nanoscale Components, Inc. | Method for alkaliating electrodes |
| US9139441B2 (en) | 2012-01-19 | 2015-09-22 | Envia Systems, Inc. | Porous silicon based anode material formed using metal reduction |
| KR20130118716A (en) | 2012-04-20 | 2013-10-30 | 주식회사 엘지화학 | Electrode assembly, battery cell and device comprising the same |
| US10553871B2 (en) | 2012-05-04 | 2020-02-04 | Zenlabs Energy, Inc. | Battery cell engineering and design to reach high energy |
| US9780358B2 (en) | 2012-05-04 | 2017-10-03 | Zenlabs Energy, Inc. | Battery designs with high capacity anode materials and cathode materials |
| KR101387424B1 (en) * | 2012-11-22 | 2014-04-25 | 주식회사 엘지화학 | Electrode assembly composed of electrode units with equal widths and different lengths, battery cell and device including the same |
| US9748599B2 (en) | 2013-01-30 | 2017-08-29 | Nanoscale Components, Inc. | Phased introduction of lithium into the pre-lithiated anode of a lithium ion electrochemical cell |
| KR101603635B1 (en) * | 2013-04-11 | 2016-03-15 | 주식회사 엘지화학 | Electrode Laminate Comprising Electrodes with Different Surface Areas and Secondary Battery Employed with the Same |
| WO2015024004A1 (en) | 2013-08-16 | 2015-02-19 | Envia Systems, Inc. | Lithium ion batteries with high capacity anode active material and good cycling for consumer electronics |
| FR3017489B1 (en) * | 2014-02-11 | 2016-01-29 | Renault Sas | LITHIUM ION BATTERY COMPRISING A LITHIUM RICH CATHODE AND A GRAPHITE-BASED ANODE |
| JP2016027562A (en) * | 2014-07-04 | 2016-02-18 | 株式会社半導体エネルギー研究所 | Secondary battery manufacturing method and manufacturing apparatus |
| JP6723023B2 (en) * | 2015-02-24 | 2020-07-15 | 株式会社半導体エネルギー研究所 | Method for manufacturing secondary battery electrode |
| FR3042914B1 (en) | 2015-10-21 | 2017-11-17 | Renault | PROCESS FOR MANUFACTURING A LITHIUM-ION TYPE BATTERY |
| FR3042915B1 (en) | 2015-10-21 | 2017-12-15 | Commissariat Energie Atomique | PROCESS FOR PRODUCING A SODIUM-ION-TYPE BATTERY |
| EP4235907A3 (en) | 2016-04-06 | 2023-11-08 | Rochester Institute of Technology | Near zero volt storage tolerant electrochemical cells through reversible ion management |
| WO2018087966A1 (en) * | 2016-11-11 | 2018-05-17 | 日本碍子株式会社 | Ic power source, various ic products provided with same, method for supplying power to ic, and method for driving ic |
| EP3652795A4 (en) | 2017-07-10 | 2021-03-10 | Nanoscale Components, Inc. | Method for forming an sei layer on an anode |
| CN110945743B (en) * | 2017-07-28 | 2023-10-27 | 株式会社村田制作所 | Charging device and charging method |
| FR3074967B1 (en) | 2017-12-08 | 2021-04-23 | Commissariat Energie Atomique | CURRENT COLLECTOR AND CURRENT COLLECTOR-ELECTRODE ASSEMBLY FOR ACCUMULATOR OPERATING ACCORDING TO THE PRINCIPLE OF IONIC INSERTION AND DISINSERTION |
| US11094925B2 (en) | 2017-12-22 | 2021-08-17 | Zenlabs Energy, Inc. | Electrodes with silicon oxide active materials for lithium ion cells achieving high capacity, high energy density and long cycle life performance |
| CN110896143B (en) * | 2018-09-13 | 2021-08-06 | 宁德时代新能源科技股份有限公司 | Lithium Ion Battery |
| US20200194749A1 (en) * | 2018-12-14 | 2020-06-18 | TeraWatt Technolgy Inc. | Prelithiated anode in battery cells for electric vehicles |
| JP6896783B2 (en) * | 2019-03-11 | 2021-06-30 | 株式会社東芝 | Rechargeable battery system, rechargeable battery, and assembled battery system |
| KR102339127B1 (en) * | 2020-05-26 | 2021-12-15 | 전북대학교산학협력단 | Hierarchical transition metal chalcogenides for flexible super capacitor, flexible super capacitor comprising the same and manufacturing method thereof |
| FR3130456B1 (en) | 2021-12-09 | 2024-04-26 | Commissariat Energie Atomique | SPECIFIC POSITIVE ELECTRODES COMPRISING A SPECIFIC SALT FOR ALKALINE METAL-ION TYPE BATTERY |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1296766C (en) * | 1986-05-13 | 1992-03-03 | Yuzuru Takahashi | Secondary battery |
| JP3028582B2 (en) * | 1990-10-09 | 2000-04-04 | ソニー株式会社 | Non-aqueous electrolyte secondary battery |
| DE4101533A1 (en) * | 1991-01-19 | 1992-07-23 | Varta Batterie | ELECTROCHEMICAL SECONDARY ELEMENT |
| JPH05101818A (en) * | 1991-08-07 | 1993-04-23 | Mitsubishi Gas Chem Co Inc | Carbon molded body for negative electrode and lithium secondary battery |
| US5340670A (en) * | 1992-06-01 | 1994-08-23 | Kabushiki Kaisha Toshiba | Lithium secondary battery and method of manufacturing carbonaceous material for negative electrode of the battery |
| US5422203A (en) * | 1992-09-28 | 1995-06-06 | Bell Communications Research, Inc. | Rapid reversible intercalation of lithium into carbon secondary battery electrodes |
| US5436093A (en) * | 1993-04-30 | 1995-07-25 | California Institute Of Technology | Method for fabricating carbon/lithium-ion electrode for rechargeable lithium cell |
| EP0627776B1 (en) * | 1993-05-14 | 1997-08-13 | Sharp Kabushiki Kaisha | Lithium secondary battery |
| FR2724490B1 (en) * | 1994-09-09 | 1996-10-25 | Lorraine Carbone | CARBON / POLYMER COMPOSITE ELECTRODE FOR LITHIUM RECHARGEABLE ELECTROCHEMICAL GENERATOR |
| US5595837A (en) * | 1995-04-12 | 1997-01-21 | Valence Technology, Inc. | Process for prelithiation of carbon based anodes for lithium batteries |
| EP0752727B1 (en) * | 1995-07-03 | 1999-12-01 | General Motors Corporation | Method for manufacturing lithium-deactivated carbon anodes |
-
1996
- 1996-02-22 US US08/604,220 patent/US5721067A/en not_active Expired - Lifetime
-
1997
- 1997-02-12 CA CA002218709A patent/CA2218709C/en not_active Expired - Lifetime
- 1997-02-12 CN CN97190138A patent/CN1114236C/en not_active Expired - Lifetime
- 1997-02-12 DE DE69707622T patent/DE69707622T2/en not_active Expired - Lifetime
- 1997-02-12 JP JP52967597A patent/JP3206604B2/en not_active Expired - Lifetime
- 1997-02-12 KR KR1019970707490A patent/KR100320999B1/en not_active Expired - Fee Related
- 1997-02-12 EP EP97902122A patent/EP0845158B1/en not_active Expired - Lifetime
- 1997-02-12 BR BR9702193-8A patent/BR9702193A/en not_active Application Discontinuation
- 1997-02-12 WO PCT/CA1997/000097 patent/WO1997031401A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| DE69707622D1 (en) | 2001-11-29 |
| EP0845158A1 (en) | 1998-06-03 |
| KR19990007966A (en) | 1999-01-25 |
| BR9702193A (en) | 1999-12-28 |
| EP0845158B1 (en) | 2001-10-24 |
| JP3206604B2 (en) | 2001-09-10 |
| KR100320999B1 (en) | 2002-06-24 |
| JPH10512712A (en) | 1998-12-02 |
| CA2218709A1 (en) | 1997-08-28 |
| CN1114236C (en) | 2003-07-09 |
| CN1185860A (en) | 1998-06-24 |
| DE69707622T2 (en) | 2002-08-01 |
| US5721067A (en) | 1998-02-24 |
| WO1997031401A1 (en) | 1997-08-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2218709C (en) | Rechargeable lithium battery having improved reversible capacity | |
| US4002492A (en) | Rechargeable lithium-aluminum anode | |
| US6955866B2 (en) | Coated lithium electrodes | |
| EP1162675A2 (en) | Negative electrode of lithium secondary battery | |
| US20040029011A1 (en) | Cathode compositions and use thereof, particularly in electrochemical generators | |
| EP0347952A2 (en) | Negative electrodes for non-aqueous secondary batteries composed of sodium alloy | |
| US4849309A (en) | Overcharge tolerant high-temperature cells and batteries | |
| KR20210021777A (en) | Lithium Anode-free All Solid State Battery Using Sacrificial Cathode Materials | |
| US4753858A (en) | Rechargeable sodium alloy anode | |
| KR100447792B1 (en) | A lithium electrode dispersed in porous 3-dimensional current collector, its fabrication method and lithium battery comprising the same | |
| Kumar et al. | Solid-state Mg/MnO2 cell employing a gel polymer electrolyte of magnesium triflate | |
| CA1309459C (en) | Electrochemical cell | |
| KR20030028241A (en) | Negative active material for lithium secondary battery and method of preparing same | |
| Huggins | Alternative materials for negative electrodes in lithium systems | |
| CN110752376A (en) | A kind of preparation method and application of metal-amalgam active current collector formed in situ | |
| US5712057A (en) | Poly-sulfide and carbon electrode material and associated process | |
| US5168020A (en) | Rechargeable sodium alloy anode | |
| JPH10302776A (en) | All-solid lithium secondary battery | |
| Xue et al. | Effect of cathodeanode mass ratio in lithium-ion secondary cells | |
| JP2001143690A (en) | Lithium secondary battery | |
| US5645953A (en) | Secondary battery and method for controlling the self-discharge of a nickel/metal hydride secondary battery | |
| GB2100497A (en) | High temperature solid state storage cell | |
| CA1166686A (en) | Rechargeable cell | |
| JP3212018B2 (en) | Non-aqueous electrolyte secondary battery | |
| WO1989004066A1 (en) | Rechargeable battery cathode from p2-phase sodium cobalt dioxide |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20170213 |