CN115498271A - Preparation method of high specific energy lithium battery - Google Patents

Preparation method of high specific energy lithium battery Download PDF

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Publication number
CN115498271A
CN115498271A CN202210652832.6A CN202210652832A CN115498271A CN 115498271 A CN115498271 A CN 115498271A CN 202210652832 A CN202210652832 A CN 202210652832A CN 115498271 A CN115498271 A CN 115498271A
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lithium battery
positive
pole piece
negative
carbon
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高艺珂
蒋阳强
向枫
刘新军
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Sichuan Changhong Battery Co ltd
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Sichuan Changhong Battery Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a preparation method of a lithium battery with high specific energy, which improves the preparation process of the lithium battery, adopts composite materials consisting of nickel cobalt lithium manganate, silicon monoxide and carbon as preparation raw materials of a positive electrode and a negative electrode of the lithium battery respectively, improves adhesives adopted by positive active substances and negative active substances, improves steps and specific process parameters in a coating process, and finally obtains a lithium battery product with high specific energy, wherein the mass specific energy of the prepared lithium battery reaches 308Wh/kg, which is far higher than that of the current domestic common lithium battery, and provides favorable technical support for further popularization of the application of the lithium battery and adjustment of a new energy structure.

Description

Preparation method of high specific energy lithium battery
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a preparation method of a lithium battery with high specific energy.
Background
Since the human society has rapidly expanded its population since its introduction into the industrialized society, the human society has an increasing demand for traditional fossil energy such as petroleum, coal mine and natural gas, but the existing amount of traditional fossil energy is limited and non-renewable, and thus the development of new renewable energy is urgent.
The lithium ion battery is an important component of the current new energy, and has the advantages of low production cost, high specific energy, high working voltage and long cycle life. At present, lithium ion batteries are widely applied to large-scale energy storage equipment, new energy automobiles and small household appliances. The mass specific energy of the lithium ion battery commonly used in China is basically in the interval of 100 Wh/kg-280 Wh/kg, and in the face of the increasing energy demand in industrial production, the mass specific energy of the lithium ion battery can not meet the demand at present, and the lithium ion battery with high specific energy must be further developed, so that the capacity of energy storage equipment is increased, the driving range of a new energy automobile is increased, and the service life of household appliances is prolonged.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the preparation method of the lithium battery with high specific energy is provided, and the mass specific energy of the prepared lithium battery product can be effectively improved.
In order to solve the technical problems, the invention adopts the technical scheme that: a preparation method of a high specific energy lithium battery comprises the following steps:
step one, stirring and dispersing a positive active material, a conductive agent and a first adhesive in sequence, uniformly mixing to prepare positive active slurry, and stirring a negative active material, a conductive agent and a second adhesive in sequence, uniformly mixing to prepare negative active slurry;
step two, respectively coating the positive active slurry and the negative active slurry obtained in the step one on a first current collector and a second current collector, and drying to obtain a positive pole piece and a negative pole piece;
step three, rolling and compacting the positive pole piece and the negative pole piece obtained in the step two;
step four, die cutting the compacted positive pole piece and negative pole piece;
adding diaphragms into the die-cut positive pole piece and negative pole piece for lamination processing to prepare a battery cell and welding a tab on the battery cell;
putting the battery core into the aluminum-plastic film shell for primary sealing and drying;
and seventhly, injecting electrolyte into the dried battery cell, performing secondary sealing, forming and grading to obtain a high-specific energy lithium battery finished product.
Further, the method comprises the following steps: in the first step, the positive active substance is nickel cobalt lithium manganate, and the negative active substance is a composite material consisting of silicon monoxide and carbon.
Further, the method comprises the following steps: the content of nickel in the nickel cobalt lithium manganate is more than 80%, the D50 of the nickel cobalt lithium manganate material is 8-12 μm, the first charge-discharge efficiency of the nickel cobalt lithium manganate is more than 90%, and the first discharge specific capacity of the nickel cobalt lithium manganate is more than 200mAh/g; the composite material D50 composed of the silicon oxide and the carbon is 8-12 mu m, the charge-discharge first efficiency of the composite material composed of the silicon oxide and the carbon is more than 80%, and the first discharge specific capacity of the composite material composed of the silicon oxide and the carbon is more than 500mAh/g.
Further, the method comprises the following steps: in the first step, the first adhesive is a glue solution prepared by dissolving polyvinylidene fluoride powder in N-methyl pyrrolidone; the second adhesive is glue solution prepared by mixing sodium carboxymethylcellulose, styrene-butadiene rubber, polyacrylic acid and water.
Further, the method comprises the following steps: the first adhesive has a viscosity of 4000 to 30000mPa £ s; the second adhesive has a viscosity of 2000-20000 mPa.
Further, the method comprises the following steps: in the second step, the first current collector is an aluminum foil or a carbon-coated aluminum foil, and the second current collector is a copper foil or a carbon-coated copper foil; during coating, the single-side surface density of the positive active slurry coating is controlled to be 210g/m 2 ～270g/m 2 The density of the single-side surface coated with the negative active slurry was controlled to 65g/m 2 ～85g/m 2 。
Further, the method comprises the following steps: in the second step, the drying temperature of the coated positive active slurry is 80-130 ℃, and the drying temperature of the coated negative active slurry is 40-70 ℃.
Further, the method comprises the following steps: in the third stepThe compacted density of the positive pole piece after rolling is 3.1g/cm 3 ～3.5g/cm 3 The compacted density of the rolled negative pole piece is 1.3g/cm 3 ～1.9g/cm 3 。
Further, the method comprises the following steps: in the sixth step, the first sealing temperature is 180-220 ℃, and the first sealing time is 4-9 s; the drying temperature is 80-95 ℃, and the drying time is 24-36 h.
Further, the method comprises the following steps: in the seventh step, the injection flow of the electrolyte is 1.9 g/Ah-3.5 g/Ah.
The invention has the beneficial effects that: the invention improves the preparation process of the lithium battery, the composite material consisting of the nickel cobalt lithium manganate, the silicon monoxide and the carbon is respectively used as the preparation raw materials of the positive electrode and the negative electrode of the lithium battery, meanwhile, the adhesive used by the positive active material and the negative active material is improved, and the steps and specific process parameters in the coating process are improved, so that the lithium battery product with high specific energy is finally obtained, and the specific mass energy of the prepared lithium battery reaches 308Wh/kg and is far higher than the specific mass energy of the current domestic common lithium battery. The lithium battery prepared by the invention can be widely applied to large energy storage equipment and other electric equipment facilities, and has the characteristics of high specific energy, low cost, no maintenance and the like; the invention provides favorable technical support for further popularization of lithium battery application and new energy structure adjustment.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be further described with reference to the following examples.
The invention discloses a preparation method of a high specific energy lithium battery, which is carried out according to the following steps when the high specific energy lithium battery is prepared:
step one, preparation and preparation of positive and negative electrode active slurry
The lithium nickel cobalt manganese oxide is used as an active substance of a positive electrode, the content of nickel in the lithium nickel cobalt manganese oxide is more than 80%, the D50 of the lithium nickel cobalt manganese oxide material is 8-12 mu m, the first charge-discharge efficiency of the lithium nickel cobalt manganese oxide is more than 90%, and the first discharge specific capacity of the lithium nickel cobalt manganese oxide is more than 200mAh/g;
the composite material composed of the silicon oxide and the carbon is used as a negative active substance, the D50 of the composite material composed of the silicon oxide and the carbon is 8-12 mu m, the charge-discharge first efficiency of the composite material composed of the silicon oxide and the carbon is more than 80%, and the first discharge specific capacity of the composite material composed of the silicon oxide and the carbon is more than 500mAh/g;
taking a glue solution prepared by dissolving polyvinylidene fluoride powder in N-methylpyrrolidone as a first adhesive, wherein the viscosity of the first adhesive is between 4000 and 30000mPa s;
taking a glue solution prepared by mixing sodium carboxymethylcellulose, styrene-butadiene rubber, polyacrylic acid and water as a second adhesive, wherein the viscosity of the second adhesive is between 2000 and 20000mPa, and the value is set;
after the raw materials are prepared, the positive active material, the conductive agent and the first adhesive are sequentially stirred and dispersed, then uniformly mixed and prepared into positive active slurry, and the negative active material, the conductive agent and the second adhesive are sequentially stirred, then uniformly mixed and prepared into negative active slurry.
Step two, coating process of positive and negative pole pieces
Coating the positive electrode active slurry obtained in the first step on a first current collector, and coating the negative electrode active slurry obtained in the first step on a second current collector; during coating, the single-side surface density of the positive active slurry coating is controlled to be 210g/m 2 ～270g/m 2 The density of the single-side surface coated with the negative active slurry is controlled to be 65g/m 2 ～85g/m 2 (ii) a The first current collector adopts aluminum foil or carbon-coated aluminum foil, and the thickness of the first current collector is 10-14 mu m; the second current collector adopts copper foil or carbon-coated copper foil, and the thickness of the second current collector is 6-10 mu m;
after coating, drying the current collector, wherein the drying temperature of the coated positive active slurry is 80-130 ℃, and the drying temperature of the coated negative active slurry is 40-70 ℃; and drying to obtain the positive pole piece and the negative pole piece.
Step three, compacting process of positive and negative pole pieces
By means of compacting rollersCompacting the positive pole piece and the negative pole piece obtained in the second step; the compacted density of the positive pole piece after rolling is 3.1g/cm 3 ～3.5g/cm 3 The compacted density of the rolled negative pole piece is 1.3g/cm 3 ～1.9g/cm 3 。
Step four, die cutting process for positive and negative pole pieces
Die cutting the compacted positive pole piece and negative pole piece; in the die cutting process, the die-cut length of the positive pole piece is 165-175 mm, the die-cut width of the positive pole piece is 95-105 mm, and the die-cut length and width of the negative pole piece are 2-5 mm larger than those of the positive pole piece.
Step five, laminating process of positive and negative pole pieces
Adding the diaphragm into the positive pole piece and the negative pole piece after die cutting for lamination treatment, wherein the number of the laminated pieces of the positive pole piece is 25-50, and the number of the laminated pieces of the negative pole piece is 1 more than that of the positive pole piece; in the lamination process, a Z-shaped lamination mode is adopted for lamination;
welding a tab on the battery cell after the lamination is prepared into the battery cell; the positive electrode lug is an aluminum lug, and the thickness of the positive electrode lug is 0.2 mm-0.3 mm; the negative pole lug is a nickel lug, and the thickness of the negative pole lug is 0.2 mm-0.3 mm.
Because the raw materials selected by the positive pole piece and the negative pole piece are both materials with larger specific capacity, and the thicknesses of the first current collector and the second current collector are both thinner, the number of laminated pieces is more during lamination, and the areas of the positive pole piece and the negative pole piece are both larger, the mass specific energy of the whole lithium battery can be effectively improved.
Step six, sealing the battery cell
Putting the prepared battery core into an aluminum-plastic film shell for sealing and drying; the first sealing temperature is 180-220 ℃, and the first sealing time is 4-9 s; the drying temperature is 80-95 ℃, and the drying time is 24-36 h;
step seven, secondary sealing of battery core
Injecting electrolyte into the dried battery cell, wherein the injection flow of the electrolyte is 1.9 g/Ah-3.5 g/Ah; and then carrying out secondary sealing, formation and capacity grading to obtain a high-specific energy lithium battery finished product.
Example 1
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 205mAh/g, the first effect is 91%, and the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 600mAh/g, and the first effect is 81%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 microns, coating the negative active slurry on a copper foil with the thickness of 6 microns, and drying to obtain a positive pole piece and a negative pole piece; the surface density of the coating single surface of the positive electrode is 255g/m 2 The surface density of the coated single surface of the negative electrode is controlled to be 75g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step three, rolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.2g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.6g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the positive pole piece after die cutting is 170mm, and the width of the positive pole piece after die cutting is 105mm; the length of the die-cut negative pole piece is 174mm, and the width of the die-cut negative pole piece is 108mm.
Step five, laminating the die-cut positive and negative electrode plates and the diaphragm to prepare a battery core and welding a tab; the number of the laminated pieces is 30 positive pole pieces, 31 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lug is welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum-plastic film shell for first sealing and drying; the first sealing temperature is 190 ℃, and the first sealing time is 6s; the drying time was 30h and the drying temperature was 85 ℃.
And step seven, injecting electrolyte into the battery core obtained in the step six, injecting the electrolyte according to the electrolyte injection amount of 2.5g/Ah, and performing secondary sealing, formation and capacity grading to obtain the finished product of the high-specific-energy lithium battery.
The performance test of the battery prepared in example 1 shows that the discharge capacity of the finished lithium battery is about 48Ah, the total weight is about 560g, and the specific discharge energy is about 308Wh/kg.
Example 2
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 210mAh/g, the first effect is 91%, the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 550mAh/g, and the first effect is 85%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 microns, coating the negative active slurry on a copper foil with the thickness of 6 microns, and drying to obtain a positive pole piece and a negative pole piece; the surface density of the coating single surface of the positive electrode is 240g/m 2 The surface density of the negative coating single surface is controlled to be 83g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step three, rolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.4g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.6g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the die-cut positive pole piece is 165mm, and the width of the die-cut positive pole piece is 100mm; the length of the die-cut negative pole piece is 168mm, and the width of the die-cut negative pole piece is 104mm.
Step five, laminating the die-cut positive and negative electrode plates and the diaphragm to prepare a battery core and welding a tab; the number of the laminated pieces is 35 positive pole pieces and 36 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lug is welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum-plastic film shell for first sealing and drying; the first sealing temperature is 200 ℃, and the first sealing time is 4s; the drying time was 24h and the drying temperature was 85 ℃.
And step seven, injecting electrolyte into the battery core obtained in the step six, injecting the electrolyte according to the electrolyte injection amount of 2.8g/Ah, and performing secondary sealing, formation and capacity grading to obtain the finished product of the high-specific-energy lithium battery.
The performance test of the battery prepared in example 2 shows that the discharge capacity of the finished lithium battery is about 52Ah, the total weight is about 620g, and the specific discharge energy is about 308Wh/kg.
Example 3
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 205mAh/g, the first effect is 91%, the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 500mAh/g, and the first effect is 92%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 microns, coating the negative active slurry on a copper foil with the thickness of 6 microns, and drying to obtain a positive pole piece and a negative pole piece; the surface density of the coating single surface of the positive electrode is 210g/m 2 The density of the single-side surface of the negative coating is controlled to be 84g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step three, rolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.3g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.5g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the die-cut positive pole piece is 165mm, and the width of the die-cut positive pole piece is 95mm; the length of the die-cut negative pole piece is 167mm, and the width of the die-cut negative pole piece is 97mm.
Step five, laminating the die-cut positive and negative electrode plates and the diaphragm to prepare a battery core and welding a tab; the number of the laminated pieces is 25 positive pole pieces and 26 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lug is welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum plastic film shell for first sealing and drying; the first sealing temperature is 205 ℃, and the first sealing time is 4s; the drying time was 24h and the drying temperature was 90 ℃.
And step seven, injecting electrolyte into the battery core obtained in the step six, injecting the electrolyte according to the electrolyte injection amount of 2.5g/Ah, and performing secondary sealing, formation and capacity grading to obtain the finished product of the high-specific-energy lithium battery.
The performance test of the battery prepared in example 3 shows that the discharge capacity of the finished lithium battery is about 33Ah, the total weight is about 397g, and the specific discharge energy is about 308Wh/kg.
Comparative example 1
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 205mAh/g, the first effect is 91%, the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 600mAh/g, and the first effect is 81%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 microns, coating the negative active slurry on a copper foil with the thickness of 6 microns, and drying to obtain a positive pole piece and a negative pole piece; the surface density of the single surface of the anode coating is 180g/m 2 The surface density of the coated single surface of the negative electrode is controlled to be 50g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step threeRolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.2g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.6g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the positive pole piece after die cutting is 170mm, and the width of the positive pole piece after die cutting is 105mm; the length of the die-cut negative pole piece is 174mm, and the width of the die-cut negative pole piece is 108mm.
Step five, preparing a battery core by laminating the die-cut positive and negative pole pieces and the diaphragm, and welding a tab; the number of the laminated pieces is 30 positive pole pieces, 31 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lug is welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum-plastic film shell for first sealing and drying; the first sealing temperature is 190 ℃, and the first sealing time is 6s; the drying time was 30h and the drying temperature was 85 ℃.
And seventhly, injecting electrolyte into the battery cell obtained in the sixth step, injecting the electrolyte according to the electrolyte injection amount of 2.5g/Ah, and performing secondary sealing, formation and capacity grading to obtain the high-specific-energy lithium battery finished product.
The performance test of the battery prepared in the comparative example 1 shows that the discharge capacity of the finished lithium battery is about 32Ah, the total weight is about 414g, and the specific discharge energy is about 282Wh/kg.
Comparative example 2
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 205mAh/g, the first effect is 91%, the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 600mAh/g, and the first effect is 81%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 μmCoating the negative active slurry on a copper foil with the thickness of 6 mu m, and drying to obtain a positive pole piece and a negative pole piece; the surface density of the coating single surface of the positive electrode is 255g/m 2 The surface density of the coated single surface of the negative electrode is controlled to be 75g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step three, rolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.2g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.6g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the positive pole piece after die cutting is 170mm, and the width of the positive pole piece after die cutting is 105mm; the length of the negative pole piece after die cutting is 174mm, and the width is 108mm.
Step five, laminating the die-cut positive and negative electrode plates and the diaphragm to prepare a battery core and welding a tab; the number of the laminated pieces is 10 positive pole pieces and 11 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lugs are welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum-plastic film shell for first sealing and drying; the first sealing temperature is 190 ℃, and the first sealing time is 6s; the drying time was 30h and the drying temperature was 85 ℃.
And step seven, injecting electrolyte into the battery core obtained in the step six, injecting the electrolyte according to the electrolyte injection amount of 2.5g/Ah, and performing secondary sealing, formation and capacity grading to obtain the finished product of the high-specific-energy lithium battery.
The performance test of the battery prepared in the comparative example 2 shows that the discharge capacity of the finished lithium battery is about 16Ah, the total weight is about 201g, and the specific discharge energy is about 290Wh/kg.
Comparative example 3
Step one, stirring, dispersing and uniformly mixing nickel cobalt lithium manganate, conductive carbon, carbon nano tubes, polyvinylidene fluoride and N-methyl pyrrolidone in sequence to prepare positive active slurry; sequentially stirring and uniformly mixing a composite material consisting of silicon monoxide and carbon, conductive carbon, carbon nano tubes, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid and water to prepare negative active slurry; wherein the specific capacity of the nickel cobalt lithium manganate is 160mAh/g, the first effect is 91%, the specific capacity of the composite material consisting of the silicon monoxide and the carbon is 350mAh/g, and the first effect is 81%.
Step two, coating the positive active slurry obtained in the step one on an aluminum foil with the thickness of 12 microns, coating the negative active slurry on a copper foil with the thickness of 6 microns, and drying to obtain a positive pole piece and a negative pole piece; the density of the single surface of the anode coating is 255g/m 2 The surface density of the coated single surface of the negative electrode is controlled to be 75g/m 2 (ii) a In the drying process, the temperature of the anode is controlled to be 110 ℃, and the temperature of the cathode is controlled to be 55 ℃.
Step three, rolling the positive and negative pole pieces prepared in the step two; the compacted density of the rolled positive electrode is controlled to be 3.2g/cm 3 The compacted density of the rolled negative electrode is controlled to be 1.6g/cm 3 。
Step four, die cutting is carried out on the compacted positive and negative pole pieces obtained in the step three; the length of the positive pole piece after die cutting is 170mm, and the width of the positive pole piece after die cutting is 105mm; the length of the die-cut negative pole piece is 174mm, and the width of the die-cut negative pole piece is 108mm.
Step five, laminating the die-cut positive and negative electrode plates and the diaphragm to prepare a battery core and welding a tab; the number of the laminated pieces is 30 positive pole pieces, 31 negative pole pieces, and the laminating mode is Z-shaped lamination; when the electrode lug is welded, the positive electrode adopts an aluminum electrode lug with the thickness of 0.2mm, and the negative electrode adopts a nickel electrode lug with the thickness of 0.2mm.
Step six, placing the battery core obtained in the step five into an aluminum-plastic film shell for first sealing and drying; the first sealing temperature is 190 ℃, and the first sealing time is 6s; the drying time was 30h and the drying temperature was 85 ℃.
And step seven, injecting electrolyte into the battery core obtained in the step six, injecting the electrolyte according to the electrolyte injection amount of 2.5g/Ah, and performing secondary sealing, formation and capacity grading to obtain the finished product of the high-specific-energy lithium battery.
The battery prepared in comparative example 3 was tested for performance and found to have a discharge capacity of about 12Ah, a total weight of about 191g, and a specific discharge energy of about 229Wh/kg.
As can be seen from the comparison of the data of the finished products of the above examples and comparative examples, in examples 1 to 3 using the process and process parameters disclosed in the present invention, the discharge specific energy of the finished lithium battery is about 308Wh/kg, which is in accordance with the data of the high specific energy lithium battery of the present invention; comparative example 1 does not adopt the coating density disclosed by the invention in the coating process, comparative example 2 does not adopt the lamination layer number disclosed by the invention in the lamination process, and comparative example 3 does not adopt the specific capacity of the material disclosed by the invention in the material preparation process; finally, the specific discharge energy of the lithium battery finished products obtained in comparative examples 1 to 3 is far lower than that of the lithium batteries obtained in examples 1 to 3, and the performance parameters of the high specific energy lithium battery of the invention cannot be achieved.

Claims (10)

1. A preparation method of a lithium battery with high specific energy is characterized in that: the method comprises the following steps:
step one, stirring and dispersing a positive active material, a conductive agent and a first adhesive in sequence, uniformly mixing to prepare positive active slurry, and stirring a negative active material, a conductive agent and a second adhesive in sequence, uniformly mixing to prepare negative active slurry;
step two, respectively coating the positive electrode active slurry and the negative electrode active slurry obtained in the step one on a first current collector and a second current collector, and drying to obtain a positive electrode piece and a negative electrode piece;
step three, rolling and compacting the positive pole piece and the negative pole piece obtained in the step two;
step four, die cutting the compacted positive pole piece and negative pole piece;
adding diaphragms into the die-cut positive pole piece and negative pole piece for lamination processing to prepare a battery cell and welding a tab on the battery cell;
putting the battery core into the aluminum-plastic film shell for primary sealing and drying;
and seventhly, injecting electrolyte into the dried battery cell, performing secondary sealing, forming and grading to obtain a high-specific energy lithium battery finished product.
2. A method of making a high specific energy lithium battery as claimed in claim 1, wherein: in the first step, the positive active substance is nickel cobalt lithium manganate, and the negative active substance is a composite material consisting of silicon monoxide and carbon.
3. The method of claim 2, wherein the lithium battery comprises: the content of nickel in the nickel cobalt lithium manganate is more than 80%, the D50 of the nickel cobalt lithium manganate material is 8-12 μm, the first charge-discharge efficiency of the nickel cobalt lithium manganate is more than 90%, and the first discharge specific capacity of the nickel cobalt lithium manganate is more than 200mAh/g; the composite material D50 composed of the silicon oxide and the carbon is 8-12 mu m, the charge-discharge first efficiency of the composite material composed of the silicon oxide and the carbon is more than 80%, and the first discharge specific capacity of the composite material composed of the silicon oxide and the carbon is more than 500mAh/g.
4. The method of claim 1, wherein the lithium battery comprises: in the first step, the first adhesive is a glue solution prepared by dissolving polyvinylidene fluoride powder in N-methyl pyrrolidone; the second adhesive is glue solution prepared by mixing sodium carboxymethylcellulose, styrene-butadiene rubber, polyacrylic acid and water.
5. The method of claim 4, wherein the lithium battery comprises: the first adhesive has a viscosity of 4000 to 30000mPa £ s; the second adhesive has a viscosity of 2000-20000 mPa.
6. The method of claim 1, wherein the lithium battery comprises: in the second step, the first current collector is an aluminum foil or a carbon-coated aluminum foil, and the second current collector is a copper foil or a carbon-coated copper foil; during coating, the single-side surface density of the positive active slurry coating is controlled to be 210g/m 2 ～270g/m 2 The density of the single-side surface coated with the negative active slurry is controlled to be 65g/m 2 ～85g/m 2 。
7. The method of claim 1, wherein the lithium battery comprises: in the second step, the drying temperature of the coated positive active slurry is 80-130 ℃, and the drying temperature of the coated negative active slurry is 40-70 ℃.
8. The method of claim 1, wherein the lithium battery comprises: in the third step, the compacted density of the positive pole piece after rolling is 3.1g/cm 3 ～3.5g/cm 3 The compacted density of the rolled negative pole piece is 1.3g/cm 3 ～1.9g/cm 3 。
9. The method of claim 1, wherein the lithium battery comprises: in the sixth step, the first sealing temperature is 180-220 ℃, and the first sealing time is 4-9 s; the drying temperature is 80-95 ℃, and the drying time is 24-36 h.
10. The method of claim 1, wherein the lithium battery comprises: in the seventh step, the injection flow of the electrolyte is 1.9 g/Ah-3.5 g/Ah.
CN202210652832.6A 2022-06-08 2022-06-08 Preparation method of high specific energy lithium battery Pending CN115498271A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116093254A (en) * 2023-04-07 2023-05-09 宁德时代新能源科技股份有限公司 Battery monomer, battery and electric equipment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116093254A (en) * 2023-04-07 2023-05-09 宁德时代新能源科技股份有限公司 Battery monomer, battery and electric equipment
CN116093254B (en) * 2023-04-07 2023-09-08 宁德时代新能源科技股份有限公司 Battery monomer, battery and electric equipment

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