CN112289989A - Ultralow-temperature lithium iron phosphate lithium ion battery - Google Patents

Ultralow-temperature lithium iron phosphate lithium ion battery Download PDF

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CN112289989A
CN112289989A CN202011084489.7A CN202011084489A CN112289989A CN 112289989 A CN112289989 A CN 112289989A CN 202011084489 A CN202011084489 A CN 202011084489A CN 112289989 A CN112289989 A CN 112289989A
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iron phosphate
conductive agent
lithium iron
ion battery
lithium ion
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卢孟萍
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Changzhou Gaotai Information Technology 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
    • 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
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
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    • Y02E60/10—Energy storage using batteries

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Abstract

The invention discloses an ultralow-temperature lithium iron phosphate lithium ion battery which comprises a positive plate, a negative plate, a diaphragm and electrolyte, wherein the positive plate comprises 90-95% of lithium iron phosphate particles, 1.5-3.5% of polyvinylidene fluoride and 2-6% of uniformly dispersed composite conductive agent, which are coated on an aluminum foil according to mass percentage: the composite conductive agent comprises a granular zero-dimensional conductive agent, a linear one-dimensional conductive agent and a flaky two-dimensional conductive agent; the composite conductive agent is uniformly dispersed among the lithium iron phosphate particles; the invention effectively constructs a three-dimensional conductive network, improves the contact between the anode material and the conductive agent, and improves the rate capability of the battery under the low-temperature condition.

Description

Ultralow-temperature lithium iron phosphate lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to an ultralow-temperature lithium iron phosphate lithium ion battery.
Background
Lithium ion batteries are widely used in the fields of power, energy storage, consumer electronics, and the like due to the advantages of high energy density, long cycle life, green environmental protection, and the like. Due to the chemical characteristics of the lithium ion battery, the dynamic performance of the lithium ion battery is poor at low temperature, so the charging and discharging performance at low temperature is relatively poor, the conventional lithium iron system battery discharges at the low temperature of-20 ℃ and 1C, the discharging capacity proportion is 50-60%, and the capacity proportion is lower under the condition of high-rate discharge, so that the energy cannot be effectively utilized, and great waste is caused.
The graphene conductive agent is a novel conductive agent developed in nearly two years, and forms a conductive network under the condition of small addition amount, and due to the two-dimensional structure of graphene, the conductive effect of an electrode is far better than that of traditional conductive agents such as conductive carbon black, but the structure of the conductive network is still imperfect, and the electronic conductivity and the ionic conductivity of the battery still need to improve the dynamic performance of the battery, especially the low-temperature dynamic performance of the battery by constructing a three-dimensional conductive network.
Disclosure of Invention
The invention aims to provide an ultralow-temperature lithium iron phosphate lithium ion battery, which effectively constructs a three-dimensional conductive network, improves the contact between a positive electrode material and a conductive agent, and improves the rate capability of the battery under a low-temperature condition.
In order to solve the technical problem, the technical scheme of the invention is as follows: an ultralow-temperature lithium iron phosphate lithium ion battery comprises a positive plate, a negative plate, a diaphragm and electrolyte, wherein the positive plate comprises 90-95% of lithium iron phosphate particles, 1.5-3.5% of polyvinylidene fluoride and 2-6% of uniformly dispersed composite conductive agent, which are coated on an aluminum foil according to mass percentage; the composite conductive agent comprises a granular zero-dimensional conductive agent, a linear one-dimensional conductive agent and a flaky two-dimensional conductive agent; the composite conductive agent is uniformly dispersed among the lithium iron phosphate particles.
Preferably, the zero-dimensional conductive agent is conductive carbon black, the linear one-dimensional conductive agent is a carbon nano tube, and the flaky two-dimensional conductive agent is graphene. The conductive carbon black (SP) belongs to a zero-dimensional conductive agent, the Carbon Nano Tube (CNT) is a one-dimensional conductive agent, the graphene is a two-dimensional conductive agent, and the three are uniformly dispersed in the lithium iron phosphate of the positive plate, so that a positive three-dimensional conductive network is effectively constructed, the power performance of the battery is favorably improved, and particularly the power performance and the safety performance in a low-temperature environment are favorably improved.
Further preferably, the mass percentages of the conductive carbon black, the carbon nanotube and the graphene are 3%, 2% and 1%, respectively. In the invention, the dosage of each substance in the positive composite conductive agent is further optimized, the coordination of conductive substances among different forms is strengthened, and the performance of the lithium iron phosphate is effectively exerted. The proportion of the three is not well controlled, the conductivity can not be exerted to the best, and the conductivity is similar to that of a single conductive agent.
The particle diameter of the lithium iron phosphate primary particle is preferably 100 to 160 nm. The lithium iron phosphate is prepared by a hydrothermal method, and primary particles are small. Compared with lithium iron phosphate synthesized by a conventional solid phase method, the lithium iron phosphate prepared by a hydrothermal method has the advantages of more uniform particle size, more regular structure, higher material conductivity and better low-temperature performance; the lithium iron phosphate with smaller primary particles is in good contact with the multidimensional three-dimensional composite conductive agent network, and the multiplying power and the low-temperature performance are both more excellent.
The preferred positive electrode sheet has an areal density of 130 to 150g/m2(ii) a The surface density of the negative plate is 60 to 80g/m2. The invention reduces the coating surface density of the anode and the cathode, shortens the transmission distance of electrons and ions, and improves the low-temperature high-rate performance of the battery.
Preferably, the diaphragm adopts a PE base film with high porosity, the thickness is 9-18 mu m, and the porosity is 40-60%. The invention utilizes the high porosity of the diaphragm, cooperates with the electrolyte, and cooperates with the design of the positive plate and the negative plate to improve the low-temperature high-rate performance of the battery.
Preferably, the electrolyte consists of a lithium salt, a solvent and an additive;
the lithium salt being LiPF6、LiPO2F2One or more of LiFSI, the concentration of lithium salt is 1.0-1.4 mol/L;
the solvent is one or more of EC (ethylene carbonate), PC (propylene carbonate), EMC (ethyl methyl carbonate), DMC (dimethyl carbonate) and EP (ethyl propionate);
the additive is one or more of VC (ethylene carbonate), FEC (fluoroethylene carbonate) and DTD (ethylene sulfate).
LiFSI and Ethyl Propionate (EP) in the electrolyte can improve the low-temperature conductivity of the electrolyte, and LiFSI and LiPO2F2Fluoroethylene carbonate (FEC) and ethylene sulfate (DTD) are beneficial to forming a low-impedance film on the surfaces of the positive electrode and the negative electrode, and the low-temperature performance of the battery is improved.
Preferably, the negative plate comprises the following substances coated on the surface of the copper foil according to mass fractions:
Figure BDA0002719887210000031
the negative electrode of the invention adopts the mixture of Vapor Grown Carbon Fiber (VGCF) and conductive carbon black (SP) as a conductive agent, the general total mass percentage of the addition amounts of SP and VGCF is 1-3% and 0.5-2%, the SP and VGCF need to be matched in a proper proportion, the SP is mainly coated on the surface of graphite to form effective short-range conduction, the VGCF is mainly connected between graphite particles to construct a long-range conductive network, and the combination of the two in a proper proportion can maximally exert the rate capability. If too much SP is used, too much SP can cause uneven dispersion and agglomeration, and too little VGCF can influence the exertion of rate performance; if the SP is too little, the VGCF is too much, the SP is too little, the coating is less, the short-range conductivity is deficient, the performance of the VGCF with too much multiplying power is improved to a limited extent, the cost is increased, and the processing performance is influenced; the three-dimensional conductive agent of the positive plate is compounded, so that the conductive performance of the positive plate and the negative plate is effectively ensured, and the low-temperature performance of the battery is improved by matching with the electrolyte; meanwhile, the negative electrode of the invention uses Styrene Butadiene Rubber (SBR) as a binder, the glass transition temperature is low, and the main chain is modified by carboxylic acid esters, so that the dynamic performance of the battery is synergistically improved.
Preferably, the graphite particles are coated with the conductive carbon black, and the vapor grown carbon fiber is dispersed among the graphite particles coated with the conductive carbon black. According to the invention, the conductive carbon black and the vapor-phase-grown carbon fiber are compounded with the graphite particles, so that the conductivity of the negative electrode is effectively improved, and the rate capability of the battery, especially the rate capability at low temperature, is improved.
Preferably, the graphite particles have a D50 of 6 to 10 μm and a compacted density of 1.3 to 1.6g/cm3. The raw material of the negative pole artificial graphite is petroleum coke or needle coke, the surface is coated by amorphous carbon, and the D50 of the graphite particles is more preferably 6-10 mu m, and the specific surface area is 1.0-3m2And/g, the ion diffusion distance is reduced, and the isotropy is increased.
The preparation method of the lithium ion battery comprises the following steps:
preparation of positive electrode
The raw materials of the positive electrode are stirred uniformly according to the proportion to form a mixture with viscosity and fluidityThe proper slurry is coated on the aluminum foil, and the coating surface density is 130-2Drying and rolling, the compaction density is 2.25-2.45g/cm3Rolling, slitting and then punching to form pole pieces;
preparation of negative electrode
The negative electrode raw materials are stirred uniformly according to a proportion to form slurry with proper viscosity and fluidity, and the slurry is coated on a copper foil, wherein the coating surface density is 60-80g/m2Drying and rolling, the compaction density is 1.3-1.6g/cm3Rolling and die-cutting into pole pieces;
preparation of battery cell
And (3) completing cell lamination of the positive plate, the negative plate and the diaphragm, punching a pit in an aluminum-plastic film, welding a tab, packaging the aluminum-plastic film, and baking. And after the battery cell is packaged, the electrolyte is used for carrying out processes of liquid injection pre-sealing, aging, pressurization formation, aging, capacity grading and the like on the battery cell, and finally the soft package lithium ion battery is manufactured.
By adopting the technical scheme, the invention has the beneficial effects that:
1. according to the invention, the granular zero-dimensional conductive agent, the linear one-dimensional conductive agent and the flaky two-dimensional conductive agent are compositely dispersed among the lithium iron phosphate particles, three conductive agents effectively construct a three-dimensional conductive network with points, lines and surfaces through the matching of the forms of the three conductive agents, and the lithium iron phosphate particles are distributed in the conductive network, so that the electronic conduction capability is effectively ensured, the capacity of the lithium iron phosphate is effectively exerted, and the lithium ion battery with high rate capability is obtained;
2. the invention can obviously improve the low-temperature discharge performance of the lithium iron phosphate system battery, and meets the requirements of 10C discharge at-20 ℃ and discharge proportion higher than 89%, and 3C discharge at-40 ℃ and discharge proportion higher than 74%, so that the use of the lithium iron battery cell under the low-temperature extreme condition is met, and the application field of the lithium iron battery cell is widened.
Thereby achieving the above object of the present invention.
Detailed Description
In order to further explain the technical solution of the present invention, the present invention is explained in detail by the following specific examples.
Example 1
The embodiment discloses an ultralow temperature lithium iron phosphate lithium ion battery;
preparation of positive electrode
The proportion of lithium iron phosphate, binder PVDF, SP, CNT and graphene is 92%: 3%: 3%: 2%: 1 percent of NMP as solvent, stirring all the components uniformly to form slurry with proper viscosity and fluidity, coating the slurry on an aluminum foil with the thickness of 16 mu m, respectively coating conductive coatings with the thickness of 2 mu m on two sides of the aluminum foil, and coating the conductive coatings with the surface density of 140g/m2Drying and rolling, the compaction density is 2.25g/cm3Rolled, slit and then die-cut into 214 x 134mm (length x width) pole pieces
Preparation of negative electrode
The using amounts of graphite, CMC, the binders SBR, SP and VGCF are respectively 92.5 percent, 2 percent, 2.5 percent, 2 percent and 1 percent by mass percent, the solvent is deionized water, all the components are uniformly stirred into slurry with proper viscosity and fluidity, the slurry is coated on a copper foil with the thickness of 8 mu m, and the coating surface density is 72g/m2Drying and rolling, the compaction density is 1.30g/cm3Die-cut 218 x 136mm (length x width) pole pieces after rolling;
diaphragm
The diaphragm adopts a wet-process base film with the thickness of 16 mu m, the width is 222mm, the porosity is 50 percent, the air permeability is 140s/100mL, and the puncture strength is more than or equal to 500 gf;
electrolyte solution
The concentration of lithium salt is 1.3mol/L, and the lithium salt is LiPF6、LiPO2F2Mixtures of LiFSI.
The solvent comprises the following components in percentage by mass: 25% EC; 5% of PC; 30% EMC; 40% EP.
The additive comprises the following components in percentage by mass of the electrolyte: 1% of VC; 2% FEC; 0.5% LiPO2F2；0.5％LiFSI；0.5％DTD；
Production of lithium ion battery
And laminating the positive plate, the negative plate and the diaphragm, punching an aluminum-plastic film, welding a tab, packaging the aluminum-plastic film, injecting liquid, aging, pressurizing to form, aging, grading and the like to manufacture the 10Ah soft package lithium ion battery.
Example 2
The embodiment discloses an ultralow temperature lithium iron phosphate lithium ion battery;
preparation of positive electrode
The mass percentages of the lithium iron phosphate, the binders PVDF, SP, CNT and the graphene are 95%, 2%, 1.5%, 1% and 0.5%, the solvent is NMP, all the components are uniformly stirred into slurry with proper viscosity and fluidity, the slurry is coated on an aluminum foil with the thickness of 16 mu m, the two sides of the aluminum foil are coated with conductive coatings of 2 mu m, and the coating surface density is 145g/m2Drying and rolling, the compaction density is 2.25g/cm3Rolled, slit and then die cut into 214 x 134mm (length x width) pole pieces.
Preparation of negative electrode
Graphite, CMC, adhesive SBR, SP and VGCF with the mass percent of 93.8%, 1.7%, 2% and 0.5%, solvent is deionized water, all the components are stirred evenly to form slurry with proper viscosity and fluidity, the slurry is coated on a copper foil with the thickness of 8 mu m, and the coating surface density is 77g/m2Drying and rolling, the compaction density is 1.30g/cm3The rolled sheet was die cut into 218 x 136mm (length x width) pieces.
Diaphragm
The diaphragm adopts a wet-process base film with the thickness of 20 mu m, the width is 222mm, the porosity is 45 percent, the air permeability is 250s/100mL, and the puncture strength is more than or equal to 500 gf.
Electrolyte solution
The lithium salt being LiPF6The concentration is 1.3 mol/L;
the solvent comprises the following components in percentage by mass: 25% EC; 5% of PC; 40% EMC; 30% DMC;
the additive comprises 0.5% of VC; 2% FEC; 1% DTD.
The lithium ion battery in this example was manufactured and tested in the same manner as in example 1.
Example 3
The embodiment discloses an ultralow temperature lithium iron phosphate lithium ion battery;
preparation of positive electrode
The mass percentages of the lithium iron phosphate, the binders PVDF, SP, CNT and graphite are 95%, 2%, 1.5%, 1% and 0.5%, and the solvent isNMP, stirring all the components uniformly to form slurry with proper viscosity and fluidity, coating the slurry on an aluminum foil with the thickness of 16 mu m, coating conductive coatings with the thickness of 2 mu m on two sides of the aluminum foil respectively, and coating the conductive coatings with the surface density of 220g/m2Drying and rolling, the compaction density is 2.3g/cm3Rolled, slit and then die cut into 214 x 134mm (length x width) pole pieces.
Preparation of negative electrode
Graphite, CMC, adhesive SBR, SP and VGCF with the mass percent of 93.8%, 1.7%, 2% and 0.5%, solvent is deionized water, all the components are stirred evenly to form slurry with proper viscosity and fluidity, the slurry is coated on a copper foil with the thickness of 8 mu m, and the coating surface density is 110g/m2Drying and rolling, the compaction density is 1.35g/cm3The rolled sheet was die cut into 218 x 136mm (length x width) pieces.
Diaphragm
The diaphragm adopts a wet-process base film with the thickness of 20 mu m, the width is 222mm, the porosity is 45 percent, the air permeability is 250s/100mL, and the puncture strength is more than or equal to 500 gf.
Electrolyte solution
Lithium salt LiPF6The concentration is 1.2 mol/L;
the solvent comprises the following components in percentage by mass: 25% EC; 5% of PC; 40% EMC; 30% DMC;
the dosage of the additive is 0.5 percent of VC; 2% FEC; 1% DTD.
The lithium ion battery was fabricated and tested in the same manner as in example 1.
To better illustrate the beneficial effects of the present invention, the following comparative tests were performed for examples 1, 2 and 3:
comparative example
The dosage and preparation method of each substance of the lithium iron phosphate lithium ion battery prepared by the embodiment are as follows:
preparation of positive electrode
The active substance of the anode material is lithium iron phosphate prepared by a solid phase method, the capacity is 140mAh/g, and the primary particle size is about 290 nm; the conductive agent of the positive electrode is SP (conductive carbon black). Lithium iron phosphate: the mass percentage of the binder PVDF to the conductive agent is 95%, 2% and 3%. Stirring all the components uniformly to obtain a pasteSlurry with proper degree and fluidity is coated on an aluminum foil with the thickness of 16 mu m, both sides of the aluminum foil are respectively coated with a conductive coating with the thickness of 2 mu m, and the coating surface density is 300g/m2Drying and rolling, the compaction density is 2.35g/cm3Rolled, slit and then die-cut into 214 x 134mm (length x width) pole pieces
Preparation of negative electrode
The negative active material was conventional secondary-particle artificial graphite, the negative D50 was 15 μm, the conductive agent used for the negative electrode was SP, and the binder used was conventional SBR (styrene butadiene rubber); the usage amounts of graphite, CMC, SBR and SP are respectively 95.9%, 1.6%, 1.5% and 1% according to the mass percentage. Stirring all components uniformly to obtain slurry with appropriate viscosity and fluidity, and coating on copper foil with thickness of 8 μm and coating surface density of 150g/m2Drying and rolling, the compaction density is 1.45g/cm3Die-cut 218X 136mm (length X width) pole pieces after rolling
Diaphragm
The diaphragm adopts a dry-process basement membrane with the thickness of 25 mu m, the width is 222mm, the porosity is 40 percent, the air permeability is 340s/100mL, and the puncture strength is more than or equal to 350gf
Electrolyte solution
The electrolyte adopts a conventional electrolyte formula, wherein the concentration of lithium salt is 1.0mol/L, the solvent EC is DEC, EMC is 35 percent, 20 percent, 45 percent and additive VC is 2 percent.
The lithium ion battery obtained in this example was fabricated and tested in the same manner as in example 1
The lithium iron phosphate lithium ion batteries prepared in examples 1 to 3 and comparative example were subjected to performance tests, the specific test methods were as follows:
1.-20 ℃ low temperature discharge test procedure:
(1) charging to 3.65V at 25 ℃ under constant current and constant voltage of 1C, stopping current at 0.05C, discharging to 2.5V under constant current of 1C, circulating for 3 times, and taking the last discharge capacity;
(2) charging to 3.65V at 25 ℃ under constant current and constant voltage of 1C, and cutting off the current of 0.05C;
(3) standing at-20 ℃ for at least 5h, then discharging to 2.0V at 0.2C, and recording the discharge capacity;
(4) standing at 25 ℃ for at least 5h, then charging to 3.65V at a constant current and a constant voltage of 1C, and stopping current at 0.05C;
(5) standing at-20 ℃ for at least 5h, then discharging to 2.0V at 0.5C, and recording the discharge capacity;
(6) repeating the steps (4) and (5), and respectively changing the current of low-temperature discharge at the temperature of-20 ℃ to 1C, 5C and 10C;
2.-40 ℃ low temperature discharge test procedure:
(1) charging to 3.65V at 25 deg.C under constant voltage and 1C, stopping current at 0.05C, discharging to 2.5V under constant current at 1C, and repeating for 3 times to obtain final discharge capacity;
(2) charging to 3.65V at 25 ℃ under constant current and constant voltage of 1C, and cutting off the current of 0.05C;
(3) standing at-40 ℃ for at least 5h, then discharging to 2.0V at 0.2C, and recording the discharge capacity;
(4) standing at 25 ℃ for at least 5h, then charging to 3.65V at a constant current and a constant voltage of 1C, and stopping current at 0.05C;
(5) standing at-40 ℃ for at least 5h, then discharging to 2.0V at 1C, and recording the discharge capacity;
(6) repeating the steps (4) and (5), and changing the current of low-temperature discharge at-40 ℃ to 3C;
the calculation method comprises the following steps:
based on 1C discharge capacity at 25 ℃, it was determined to be 100%. Calculation of discharge ratios at-20 ℃ of 0.2C, 0.5C, 1C, 5C and 10C, 9.79/10.5%
Specific test data are shown in tables 1 and 2.
TABLE 1 EXAMPLES 1 TO 3 AND COMPARATIVE EXAMPLE A lithium ion Battery having a discharge behavior in a low temperature environment (-20 ℃ C.)
Figure BDA0002719887210000101
Figure BDA0002719887210000111
Table 2 examples 1 to 3 and comparative example lithium ion batteries having discharge characteristics (-40 c) in low temperature environment were obtained
Figure BDA0002719887210000112
By combining table 1 and table 2, it can be seen intuitively from the retention rate data of low-temperature discharge at-20 ℃ and-40 ℃, that the low-temperature performance of the soft package lithium ion batteries of examples 1, 2 and 3 is obviously superior to that of the conventional soft package battery of the comparative example, wherein the low-temperature performance of example 1 is the best.
By comparing the formulations of examples 1-3 and comparative examples, the results of the tests, the following conclusions can be drawn:
(1) the proportion of the conductive agent is properly increased, the types of the conductive agent and the mutual proportion are reasonably matched, the surface density is reduced, the compaction density is reduced, and the low-temperature high-rate performance of the battery can be improved by selecting the wet-process diaphragm with high porosity.
(2) Optimizing electrolyte, and increasing low-viscosity linear carbonate and low-temperature linear carboxylate; the low-temperature high-rate performance of the battery can be improved by adding the film forming additive with high conductivity and low impedance.

Claims (10)

1. The utility model provides an ultra-low temperature lithium iron phosphate lithium ion battery, includes positive plate, negative plate, diaphragm and electrolyte, its characterized in that: the positive plate comprises 90-95% of lithium iron phosphate particles, 1.5-3.5% of polyvinylidene fluoride and 2-6% of uniformly dispersed composite conductive agent, which are coated on the aluminum foil according to the mass percentage; the composite conductive agent comprises a granular zero-dimensional conductive agent, a linear one-dimensional conductive agent and a flaky two-dimensional conductive agent; the composite conductive agent is uniformly dispersed among the lithium iron phosphate particles.
2. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 1, wherein: the zero-dimensional conductive agent is conductive carbon black, the linear one-dimensional conductive agent is a carbon nano tube, and the flaky two-dimensional conductive agent is graphene.
3. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 2, wherein: the mass percentages of the conductive carbon black, the carbon nano tube and the graphene are respectively 3%, 2% and 1%.
4. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 1, wherein: the particle size of the lithium iron phosphate primary particles is 100 to 160 nm.
5. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 1, wherein: the surface density of the positive electrode sheet is 130 to 150g/m2(ii) a The surface density of the negative plate is 60 to 80g/m2。
6. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 1, wherein: the diaphragm adopts a PE base film with high porosity, the thickness is 9-18 mu m, and the porosity is 40-60%.
7. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 1, wherein: the electrolyte consists of lithium salt, solvent and additive;
the lithium salt being LiPF6、LiPO2F2One or more of LiFSI, the concentration of lithium salt is 1.0-1.4 mol/L;
the solvent is one or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate and ethyl propionate;
the additive is one or more of ethylene carbonate, fluoroethylene carbonate and ethylene sulfate.
8. The ultra-low temperature lithium iron phosphate lithium ion battery of any one of claims 1 to 7, wherein: the negative plate comprises the following substances coated on the surface of a copper foil according to mass fractions:
Figure FDA0002719887200000021
9. the ultra-low temperature lithium iron phosphate lithium ion battery of claim 8, wherein: the conductive carbon black coats the graphite particles, and the vapor-grown carbon fibers are dispersed among the graphite particles coated with the conductive carbon black.
10. The ultra-low temperature lithium iron phosphate lithium ion battery of claim 8, wherein: the graphite particles have a D50 of 6 to 10 μm and a compacted density of 1.3 to 1.6g/cm3。
CN202011084489.7A 2020-10-12 2020-10-12 Ultralow-temperature lithium iron phosphate lithium ion battery Pending CN112289989A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114023969A (en) * 2021-11-03 2022-02-08 合肥国轩高科动力能源有限公司 3D creeper-type high-performance conductive agent and preparation method and application thereof
CN114300690A (en) * 2021-12-31 2022-04-08 珠海冠宇动力电池有限公司 Pole piece and battery
CN114447440A (en) * 2021-12-29 2022-05-06 天津先众新能源科技股份有限公司 Lithium iron phosphate battery with low-temperature high-rate discharge performance and manufacturing method thereof
CN114883529A (en) * 2022-07-06 2022-08-09 天能新能源(湖州)有限公司 Low-temperature starting lithium ion battery
CN115882081A (en) * 2023-02-17 2023-03-31 淄博火炬能源有限责任公司 Wide-temperature type lithium iron phosphate battery and manufacturing process thereof

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130164619A1 (en) * 2011-12-26 2013-06-27 Semiconductor Energy Laboratory Co., Ltd. Positive electrode for secondary battery and manufacturing method of positive electrode for secondary battery
CN105489857A (en) * 2015-12-08 2016-04-13 西安瑟福能源科技有限公司 Quick charging lithium-ion battery
CN107482253A (en) * 2017-07-18 2017-12-15 东莞市迈科新能源有限公司 A kind of low-temperature lithium ion battery
CN107623142A (en) * 2017-09-07 2018-01-23 山东鸿正电池材料科技有限公司 A kind of high power lithium ion power battery
CN109768279A (en) * 2018-12-20 2019-05-17 上海力信能源科技有限责任公司 A kind of combined conductive agent and preparation method thereof, lithium ion cell positive
CN109802094A (en) * 2017-11-15 2019-05-24 成都特隆美储能技术有限公司 A kind of low temperature ferric phosphate lithium cell and preparation method thereof
CN109817896A (en) * 2019-04-08 2019-05-28 珠海冠宇电池有限公司 A kind of preparation method and lithium ion battery of LiFePO4 anode of secondary cell
US20200203767A1 (en) * 2017-07-20 2020-06-25 Nec Corporation Carbon conductive additives for lithium ion battery

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130164619A1 (en) * 2011-12-26 2013-06-27 Semiconductor Energy Laboratory Co., Ltd. Positive electrode for secondary battery and manufacturing method of positive electrode for secondary battery
CN105489857A (en) * 2015-12-08 2016-04-13 西安瑟福能源科技有限公司 Quick charging lithium-ion battery
CN107482253A (en) * 2017-07-18 2017-12-15 东莞市迈科新能源有限公司 A kind of low-temperature lithium ion battery
US20200203767A1 (en) * 2017-07-20 2020-06-25 Nec Corporation Carbon conductive additives for lithium ion battery
CN107623142A (en) * 2017-09-07 2018-01-23 山东鸿正电池材料科技有限公司 A kind of high power lithium ion power battery
CN109802094A (en) * 2017-11-15 2019-05-24 成都特隆美储能技术有限公司 A kind of low temperature ferric phosphate lithium cell and preparation method thereof
CN109768279A (en) * 2018-12-20 2019-05-17 上海力信能源科技有限责任公司 A kind of combined conductive agent and preparation method thereof, lithium ion cell positive
CN109817896A (en) * 2019-04-08 2019-05-28 珠海冠宇电池有限公司 A kind of preparation method and lithium ion battery of LiFePO4 anode of secondary cell

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114023969A (en) * 2021-11-03 2022-02-08 合肥国轩高科动力能源有限公司 3D creeper-type high-performance conductive agent and preparation method and application thereof
CN114447440A (en) * 2021-12-29 2022-05-06 天津先众新能源科技股份有限公司 Lithium iron phosphate battery with low-temperature high-rate discharge performance and manufacturing method thereof
CN114300690A (en) * 2021-12-31 2022-04-08 珠海冠宇动力电池有限公司 Pole piece and battery
CN114883529A (en) * 2022-07-06 2022-08-09 天能新能源(湖州)有限公司 Low-temperature starting lithium ion battery
CN115882081A (en) * 2023-02-17 2023-03-31 淄博火炬能源有限责任公司 Wide-temperature type lithium iron phosphate battery and manufacturing process thereof

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Application publication date: 20210129