WO2025200484A1 - 电池、用电系统及储能系统 - Google Patents
电池、用电系统及储能系统Info
- Publication number
- WO2025200484A1 WO2025200484A1 PCT/CN2024/132009 CN2024132009W WO2025200484A1 WO 2025200484 A1 WO2025200484 A1 WO 2025200484A1 CN 2024132009 W CN2024132009 W CN 2024132009W WO 2025200484 A1 WO2025200484 A1 WO 2025200484A1
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- WIPO (PCT)
- Prior art keywords
- positive electrode
- battery
- lithium
- electrolyte
- energy storage
- 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.)
- Pending
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Classifications
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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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0568—Liquid materials characterised by the solutes
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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
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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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0028—Organic electrolyte characterised by the solvent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0028—Organic electrolyte characterised by the solvent
- H01M2300/0037—Mixture of solvents
-
- 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
Definitions
- the present application relates to the field of energy storage, and specifically to a battery, a power system, and an energy storage system.
- lithium-ion batteries have advantages over other types of batteries such as lead-acid and nickel-cadmium batteries, such as high specific capacity, no memory effect, high operating voltage, fast charging speed, wide operating temperature range, long cycle life, small size, and light weight.
- lead-acid and nickel-cadmium batteries such as high specific capacity, no memory effect, high operating voltage, fast charging speed, wide operating temperature range, long cycle life, small size, and light weight.
- lithium-ion batteries are widely used in mobile phones, laptops, electric vehicles, energy storage cabinets and other fields, and their application range is becoming increasingly wider.
- lithium-ion batteries With the development of the energy storage industry, higher requirements are placed on the fast charging and safety performance of lithium-ion batteries. However, existing lithium-ion batteries are difficult to achieve both dynamic performance and safety performance.
- the embodiments of the present application provide a battery having high dynamic performance and safety performance.
- the present application provides a battery comprising:
- An electrolyte comprising lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, wherein the mass ratio of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide in the electrolyte is ⁇ ;
- a positive electrode sheet wherein the positive electrode sheet is at least partially immersed in the electrolyte, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, the positive electrode active layer is disposed on the surface of the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material and a carbon material, and the mass fraction of the carbon material in the positive electrode active layer is B;
- the battery satisfies the relationship: 1.31 wt% ⁇ B ⁇ 10.74 wt%.
- the present application further provides an electricity system, comprising:
- An energy storage device which supplies power to the electrical equipment, and the energy storage device includes at least one battery described in an embodiment of the present application.
- the present application further provides an energy storage system, comprising:
- An electric energy conversion device the electric energy conversion device is used to convert other forms of energy into electric energy
- an energy storage device the energy storage device being electrically connected to the electric energy conversion device and configured to store the electric energy of the electric energy conversion device, the energy storage device comprising at least one battery as described in an embodiment of the present application;
- An electrical load is electrically connected to the power conversion device and the energy storage device, respectively, and is used to operate using the electrical energy of the power conversion device or the energy storage device.
- FIG1 is a diagram showing an application scenario of an energy storage system according to an embodiment of the present application.
- FIG3 is a circuit block diagram of an energy storage system according to an embodiment of the present application.
- FIG5 is a schematic structural diagram of an energy storage device according to an embodiment of the present application.
- FIG6 is a schematic structural diagram of a battery according to an embodiment of the present application.
- FIG7 is a schematic diagram of the cross-sectional structure of a battery according to an embodiment of the present application along the A-A direction in FIG6 .
- FIG8 is a schematic diagram of the cross-sectional structure of the positive electrode sheet along the A-A direction in FIG6 according to an embodiment of the present application.
- 100-Energy storage system 110-Electric energy conversion device, 130-Electric load, 200-Energy storage device, 210-Case, 300-Electric system, 310-Electric equipment, 400-Battery, 410-Positive electrode sheet, 411-Positive current collector, 412-Positive active layer, 420-Separator, 430-Negative electrode sheet, 431-Negative current collector, 432-Negative active layer, 440-Case.
- the present application provides an energy storage system 100, which is a household energy storage system 100.
- the energy storage system 100 includes an electric energy conversion device 110, an energy storage device 200, and an electrical load 130.
- the electric energy conversion device 110 is used to convert other forms of energy into electric energy;
- the energy storage device 200 is electrically connected to the electric energy conversion device 110 and is used to store the electric energy of the electric energy conversion device 110;
- the electric load 130 is electrically connected to the electric energy conversion device 110 and the energy storage device 200, respectively, and is used to use the electric energy of the electric energy conversion device 110 or the energy storage device 200 to work.
- part of the electric energy converted by the electric energy conversion device 110 is stored in the energy storage device 200, and part is used to power the electric load 130.
- the energy storage device 200 is used to store electric energy and supply the electric load 130 when the electricity price is peak.
- the energy storage system 100 can convert other generated energy into electrical energy and store the electrical energy in the energy storage device 200 to supply sufficient electrical energy to the electrical load 130 .
- the electric energy conversion device 110 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electric energy, providing a stable power supply for the electrical load 130 and the energy storage device 200.
- the power conversion device 110 may be, but is not limited to, a photovoltaic panel, which can convert solar energy into electrical energy during periods of low electricity prices and store the energy in the energy storage device 200.
- the power conversion device 110 may be at least one of a wind power generation device, a thermal power generation device, a tidal power generation device, a biomass power generation device, and a mechanical power generation device.
- the energy storage device 200 may include but is not limited to at least one of a single cell, a battery module, a battery pack, a battery system, etc.
- the single cell may be but is not limited to at least one of a cylindrical battery, a square battery, etc.
- the power-consuming device 310 in the embodiments of the present application may be, but is not limited to, a portable electronic device such as a mobile phone, tablet computer, laptop computer, desktop computer, smart bracelet, smart watch, e-reader, game console, etc.
- the power-consuming device 310 may also be a vehicle such as a car, truck, sedan, van, truck, train, high-speed train, electric vehicle, etc.
- the power-consuming device 310 may also be various household appliances such as refrigerators, electric lights, air conditioners, etc. It is understandable that the power-consuming device 310 illustrated in the drawings of this application is only one form of the power-consuming device 310 and should not be understood as limiting the power-consuming device 310 provided in this application.
- an embodiment of the present application further provides an energy storage device 200 , which includes a box 210 and a plurality of batteries 400 .
- the plurality of batteries 400 are stacked and accommodated in the box 210 .
- the battery 400 may be, but is not limited to, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, an energy storage battery, or the like.
- each receiving cavity receives one battery 400. In other embodiments, each receiving cavity receives multiple batteries 400.
- an embodiment of the present application further provides a battery 400, which includes an electrolyte, a positive electrode sheet 410, a separator 420, and a negative electrode sheet 430.
- the positive electrode sheet 410 is at least partially immersed in the electrolyte;
- the separator 420 is located on one side of the positive electrode sheet 410;
- the negative electrode sheet 430 is disposed on a side of the separator 420 facing away from the positive electrode sheet 410 and is at least partially immersed in the electrolyte.
- the electrolyte includes an electrolyte salt
- the electrolyte salt includes lithium hexafluorophosphate ( LiPF6 ) and lithium bisfluorosulfonyl imide (LiFSI).
- the mass ratio of lithium hexafluorophosphate to lithium bisfluorosulfonyl imide is ⁇ ;
- the positive electrode plate 410 includes a positive electrode collector 411 and a positive electrode active layer 412.
- the positive electrode active layer 412 is arranged on the surface of the positive electrode collector 411.
- the positive electrode active layer 412 includes a positive electrode active material and a carbon material.
- the mass fraction of the carbon material in the positive electrode active layer 412 is B; wherein the battery 400 satisfies the relationship: 1.31wt% ⁇ B ⁇ 10.74wt%.
- the positive electrode sheet 410 and the negative electrode sheet 430 may be collectively referred to as electrode sheets.
- the electrode sheets include the positive electrode sheet 410 and the negative electrode sheet 430 .
- the battery 400 further includes a housing 440 , and the housing 440 is used to accommodate the electrolyte, the positive electrode plate 410 , the separator 420 and the negative electrode plate 430 .
- the positive electrode active layer 412 may cover one surface of the positive electrode current collector 411 or may cover two opposite surfaces of the positive electrode current collector 411 .
- ⁇ B can be but is not limited to 1.31wt%, 1.5wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 10.74wt%, etc.
- ⁇ B When ⁇ B is too small, it may be that the mass ratio ⁇ of lithium hexafluorophosphate to lithium bisfluorosulfonyl imide is too small or the mass fraction B of the carbon material in the positive electrode active layer 412 is too small; when the mass ratio ⁇ of lithium hexafluorophosphate to lithium bisfluorosulfonyl imide is too small, it indicates that the content of lithium hexafluorophosphate in the electrolyte is too small and the content of lithium bisfluorosulfonyl imide is too high.
- the excessively high content of lithium bisfluorosulfonyl imide is likely to corrode the aluminum foil, thereby damaging the positive electrode sheet 410, reducing the life of the battery 400, affecting the normal operation of the battery 400, and increasing the cost of the electrolyte; when the mass fraction B of the carbon material in the positive electrode active layer 412 is too small, it is easy to make the positive electrode sheet 410 insufficient in its electron conductivity, increase the impedance of the positive electrode sheet 410, and reduce the rate performance and cycle performance of the battery 400.
- ⁇ B When ⁇ B is too large, it may be that the mass ratio ⁇ of lithium hexafluorophosphate to lithium bisfluorosulfonyl imide is too large or the mass fraction B of the carbon material in the positive electrode active layer 412 is too large; when the mass ratio ⁇ of lithium hexafluorophosphate to lithium bisfluorosulfonyl imide is too large, it indicates that the content of lithium hexafluorophosphate in the electrolyte is too high and the content of lithium bisfluorosulfonyl imide is too low, then the battery 400 is in the overcharge stage, and the hexafluorophosphate ions (PF 6 - ) is prone to decomposition to produce acid.
- PF 6 - hexafluorophosphate ions
- the electrolyte of the battery 400 has higher conductivity and the battery 400 has higher kinetic performance.
- the side reactions within the battery 400 especially those during overcharge, can be reduced, thereby reducing the temperature of the battery 400 during the overcharge stage and significantly improving the safety performance of the battery 400.
- the battery 400 satisfies the relationship: 1.8 wt% ⁇ ⁇ B ⁇ 10 wt%.
- ⁇ B is within this range, the battery 400 can better have higher dynamic performance while reducing side reactions, thereby having higher safety performance.
- the battery 400 satisfies the relationship: 2wt% ⁇ B ⁇ 9wt%.
- ⁇ B is within this range, the battery 400 can better have higher dynamic performance while reducing side reactions, thereby having higher safety performance.
- the electrolyte of the battery 400 of the embodiment of the present application includes lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide.
- the addition of lithium bis(fluorosulfonyl)imide can reduce the decomposition of hexafluorophosphate ions (PF 6 - ) in the overcharge stage of the battery 400, thereby reducing the side reactions of the battery 400 and improving the safety performance of the battery 400.
- reducing the decomposition of hexafluorophosphate ions (PF 6 - ) can better maintain the conductivity of the electrolyte, so that the battery 400 has better dynamic performance.
- the positive electrode active layer 412 includes a positive electrode active material and a carbon material.
- the addition of the carbon material in the positive electrode active layer 412 can improve the conductivity of the positive electrode plate 410, thereby further improving the kinetic performance of the battery 400.
- the content of the carbon material is too high, the side reactions will increase and the safety performance of the battery 400 will be reduced.
- the embodiment of the present application controls the content of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide and carbon material so that the battery 400 has higher kinetic performance while greatly reducing the side reactions of the battery 400 and improving the safety performance of the battery 400.
- the positive electrode active material may be, but is not limited to, lithium iron phosphate.
- the mass fraction B of the carbon material in the positive electrode active layer 412 is in the range of 1.073 wt% ⁇ B ⁇ 1.653 wt%.
- the mass fraction B of the carbon material in the positive electrode active layer 412 can be, but is not limited to, %, 1.073wt%, 1.1wt%, 1.15wt%, 1.2wt%, 1.25wt%, 1.3wt%, 1.35wt%, 1.4wt%, 1.45wt%, 1.5wt%, 1.55wt%, 1.6wt%, 1.653wt%, etc.
- the carbon material helps to form a conductive network, increase the electron transmission path, and improve the dynamics of the positive electrode plate 410.
- the electrolyte of the battery 400 has higher electron conductivity and lower impedance, thereby improving the rate performance and cycle performance of the battery 400.
- the battery 400 can have fewer side reactions when overcharged, reducing the overcharge temperature of the battery 400, and thus reducing the safety performance of the battery 400.
- the carbon material includes a carbon coating layer (also referred to as coated carbon) and conductive carbon, the carbon coating layer is wrapped around the surface of the positive electrode active material, and the conductive carbon is dispersed in the positive electrode active layer 412; in the positive electrode active layer 412, the mass ratio of the carbon coating layer to the conductive carbon is in the range of: 2.57 ⁇ B1/B2 ⁇ 4.5.
- the mass ratio B1/B2 of the carbon coating layer to the conductive carbon may be, but is not limited to, 2.57, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.5, etc.
- the mass fraction B1 of the carbon coating layer is in the range of: 0.77 wt % ⁇ B1 ⁇ 1.35 wt %.
- the mass fraction B1 of the carbon coating layer can be, but is not limited to, 0.77 wt%, 0.8 wt%, 0.87 wt%, 0.9 wt%, 0.95 wt%, 1.04 wt%, 1.1 wt%, 1.15 wt%, 1.20 wt%, 1.25 wt%, 1.30 wt%, 1.35 wt%, etc.
- the carbon coating layer in the positive electrode active layer 412 When the mass fraction B1 of the carbon coating layer in the positive electrode active layer 412 is too low, the carbon coating layer cannot completely cover the positive electrode active material, causing part of the positive electrode active material to directly contact the electrolyte, increasing the side reaction between the electrolyte and the positive electrode active layer 412, thereby increasing the consumption of the electrolyte and reducing the cycle capacity retention rate of the battery 400; in addition, the carbon coating layer also affects the construction of the conductive network at the interface of the positive electrode active layer 412. If the mass fraction of the carbon coating layer is too low, the conductive performance will be deteriorated, affecting the kinetics.
- the mass fraction B2 of the conductive carbon is in the range of: 0 ⁇ B2 ⁇ 0.3wt%.
- the mass fraction B2 of the conductive carbon can be, but is not limited to, 0.05wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, etc.
- the conductive network of the positive electrode active material (such as lithium iron phosphate) between the binders is insufficient, thereby reducing the electronic conductivity of the positive electrode active layer 412 and thus reducing the kinetic performance of the positive electrode active layer 412; in the positive electrode active layer 412, if the mass fraction B2 of the conductive carbon is too large, the viscosity of the positive electrode active layer 412 is too high during the slurrying process, increasing the difficulty of coating the positive electrode active layer 412 and affecting the performance of the gram capacity of the positive electrode active layer 412.
- the mass fraction B2 of the conductive carbon such as lithium iron phosphate
- the conductive carbon may be, but is not limited to, at least one of conductive carbon black, acetylene black, carbon nanotubes, carbon fibers, graphene, and the like.
- the carbon coating layer can be obtained by sintering a carbon source through a carbothermal reduction method.
- the carbon source may be, but is not limited to, at least one of glucose, sucrose, starch, and a high molecular weight carbon source such as PEG.
- the positive electrode active layer 412 further includes a first binder and a first thickener.
- the first binder may be, but is not limited to, at least one of polyvinylidene fluoride (PVDF), polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), polyhexafluoropropylene, and styrene-butadiene rubber (SBR).
- PVDF polyvinylidene fluoride
- PA polyamide
- PAN polyacrylonitrile
- PMMA polymethyl methacrylate
- SBR styrene-butadiene rubber
- the mass fraction of the first binder in the positive electrode active layer 412 ranges from 2 wt% to 4 wt%.
- the mass fraction of the first binder in the positive electrode active layer 412 may be, but is not limited to, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, etc. If the mass fraction of the first binder is too low, the positive electrode active layer 412 may easily pulverize or slag. If the mass fraction of the first binder is too high, the energy density of the positive electrode sheet 410 may be reduced.
- the first thickener may be, but is not limited to, at least one of sodium carboxymethyl cellulose (CMC), polyacrylamide (PAM), and polymethacrylate (PMA).
- CMC sodium carboxymethyl cellulose
- PAM polyacrylamide
- PMA polymethacrylate
- the diaphragm 420 may be, but is not limited to, at least one of a polypropylene film (PP film for short), a polyethylene film (PE film for short), a ceramic diaphragm 420 , and the like.
- PP film for short a polypropylene film
- PE film for short a polyethylene film
- ceramic diaphragm 420 a ceramic diaphragm 420 , and the like.
- the thickness of the diaphragm 420 is 14 ⁇ m to 18 ⁇ m.
- the thickness of the diaphragm 420 may be, but is not limited to, 14 ⁇ m, 14.5 ⁇ m, 15 ⁇ m, 15.5 ⁇ m, 16 ⁇ m, 16.5 ⁇ m, 17 ⁇ m, 17.5 ⁇ m, and 18 ⁇ m.
- the battery 400 can have a lower cost and a longer service life, while also having higher safety and dynamic performance.
- the mass ratio ⁇ of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide is in the range of 1.5 ⁇ ⁇ ⁇ 6.
- the mass ratio ⁇ of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide in the electrolyte is within this range, the battery 400 can have a lower cost and a longer service life while also having better overcharge resistance, safety, and dynamic performance.
- the electrolyte further includes a sulfur-containing additive.
- the sulfur-containing additive can form lithium sulfate or alkyl lithium sulfate in the positive electrode plate 410, further stabilizing the solid electrolyte interface (SEI) film of the positive electrode plate 410 and making the SEI film thinner, thereby reducing the impedance of the positive electrode plate 410 and thereby lowering the heat generated by the high temperature of the positive electrode plate 410 and improving the safety performance of the battery 400.
- SEI solid electrolyte interface
- the mass fraction w2 of the lithium salt additive is 0.2wt% ⁇ w2 ⁇ 2wt%.
- the mass fraction w2 of the lithium salt additive can be, but is not limited to, 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, etc.
- the mass fraction w2 of the lithium salt additive is too small, the reduction in the impedance of the positive electrode 410 or the negative electrode 430 is limited, and it is difficult to increase the dynamic performance of the positive electrode 410 or the negative electrode 430; if the mass fraction w2 of the lithium salt additive is too large, due to the limited solubility of the lithium salt additive, when the concentration of the lithium salt additive reaches a certain level, it will no longer have any effect on the dynamic performance of the positive electrode 410 or the negative electrode 430. However, it will greatly increase the cost of the battery 400. When the mass fraction w2 of the lithium salt additive is 0.2wt% ⁇ w2 ⁇ 2wt%, the dynamic performance of the positive electrode sheet 410 or the negative electrode sheet 430 can be improved while the cost of the battery 400 can be reduced.
- the electrolyte further includes a film-forming additive.
- the film-forming additive can be used to promote the formation of an interface film of at least one of the positive electrode plate 410 and the negative electrode plate 430 and maintain the stability of the interface film.
- the film-forming additive includes at least one of fluoroethylene carbonate (FEC), vinyl sulfate (PST), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), tris(trimethylsilyl) phosphate, tris(trimethylsilyl) borate, adiponitrile, succinonitrile, and 1,3,6-hexanonitrile.
- FEC fluoroethylene carbonate
- PST vinyl sulfate
- VC vinylene carbonate
- VEC vinyl ethylene carbonate
- tris(trimethylsilyl) phosphate tris(trimethylsilyl) borate
- adiponitrile succinonitrile
- succinonitrile 1,3,6-hexanonitrile
- the negative electrode sheet 430 includes a negative electrode current collector 431 and a negative electrode active layer 432 , wherein the negative electrode active layer 432 is disposed on the surface of the negative electrode current collector 431 . It is understood that the negative electrode active layer 432 may cover one surface or two opposite surfaces of the negative electrode current collector 431 .
- the negative electrode current collector 431 may be, but is not limited to, a copper sheet.
- the negative electrode active material may be, but is not limited to, graphite.
- the graphite may be natural graphite or artificial graphite, which is not specifically limited in this application.
- the mass fraction of the second binder in the negative electrode active layer 432 ranges from 2 wt% to 4 wt%.
- the mass fraction of the second binder in the negative electrode active layer 432 may be, but is not limited to, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, etc. If the mass fraction of the second binder is too low, the negative electrode active layer 432 may easily pulverize or slag. If the mass fraction of the second binder is too high, the energy density of the negative electrode sheet 430 may be reduced.
- the battery 400 of the embodiment of the present application has a cycle capacity retention rate of greater than or equal to 95.32% at a 1C discharge rate, and specifically, it can be, but not limited to, 95.32%, 96%, 97%, 98%, 99%, etc.
- the battery 400 of the embodiment of the present application has a cycle capacity retention rate of greater than or equal to 88.13% at a 2C discharge rate, and specifically, it can be, but not limited to, 88.13%, 90%, 91%, 92%, 93%, 94%, 95%, 95.32%, 96%, 97%, 98%, 99%, etc.
- Assembly of battery 400 The positive electrode sheet 410, the separator 420, and the negative electrode sheet 430 are stacked in sequence to form an electrode assembly.
- the electrode assembly is wound to obtain a bare cell. After welding the tabs, the cell is assembled into an outer package. After injecting the prepared electrolyte, the cell is packaged, allowed to stand, formed, shaped, and capacity tested, and finally a 3.2Ah battery 400 is prepared.
- Comparative Example 6 The difference between Comparative Example 6 and Example 13 is that the carbon material of the positive electrode active layer 412 of this comparative example only includes a carbon coating layer and does not contain conductive carbon.
- Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the carbon material of the positive electrode active layer 412 of this comparative example only includes a carbon coating layer and does not contain conductive carbon.
- the battery 400 of each embodiment and comparative example was subjected to an overcharge test and a discharge capacity retention rate test at different rates.
- the performance parameters of the battery 400 of each embodiment and comparative example are shown in Table 1 below.
- the overcharge temperature and overcharge time of each embodiment and comparative example are shown in Table 1 below.
- the “overcharge time” refers to the time required for the battery 400 to continue charging to a voltage of 1.5 times the full-charge voltage (5.475V) after being fully charged (voltage is 3.65V).
- Example 1 From the test results of Example 1, Example 5, Example 9 and Example 13, it can be seen that when the battery 400 of the embodiment of the present application satisfies 1.31wt% ⁇ B ⁇ 10.74wt%, the battery 400 of the embodiment of the present application has a high cycle capacity retention rate at both the 1C discharge rate and the 2C discharge rate, and has good rate performance. From the test results of Comparative Example 3, it can be seen that when ⁇ 1.22 and ⁇ B ⁇ 1.31wt%, although the battery 400 still has a high cycle capacity retention rate at the 1C discharge rate, the cycle capacity retention rate decreases significantly at the 2C discharge rate.
- Comparative Example 5 From the test results of Comparative Example 5, it can be seen that when ⁇ >6.5, although the battery 400 still has a high cycle capacity retention rate at the 1C discharge rate, the cycle capacity retention rate also decreases significantly at the 2C discharge rate. Furthermore, Comparative Example 4 shows that when ⁇ >6.5 and ⁇ B>10.74wt%, the cycle capacity retention rate at a 1C discharge rate and the cycle capacity retention rate at a 2C discharge rate of Comparative Example 4 are both reduced compared to Comparative Example 5. Furthermore, Comparative Examples 4 and 5 also show that when ⁇ >6.5, or ⁇ >6.5 and ⁇ B>10.74wt%, the overcharge temperature of the battery 400 increases significantly and the overcharge time becomes significantly longer, indicating that the charge resistance and safety performance of the battery 400 are reduced.
- Example 1 and Comparative Example 7 show that when the carbon material of the positive electrode active layer 412 is entirely a carbon coating layer without conductive carbon (i.e., Comparative Example 7), the cycle capacity retention rate of the battery 400 at a 1C discharge rate and the cycle capacity retention rate at a 2C discharge rate remain essentially unchanged.
- the overcharge temperature of the battery 400 increases significantly, and the overcharge time also increases, indicating that the overcharge resistance and safety performance of the battery 400 are reduced.
- references to “embodiments” and “implementation methods” in this application mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application.
- the appearance of the phrases in various places in the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described in this application may be combined with other embodiments.
- the features, structures or characteristics described in the various embodiments of the present application can be arbitrarily combined without contradiction to form another embodiment without departing from the spirit and scope of the technical solution of the present application.
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- Secondary Cells (AREA)
Abstract
一种电池、用电系统及储能系统,电池包括:电解液,所述电解液包括六氟磷酸锂及双氟磺酰亚胺锂,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比为γ;以及正极极片,所述正极极片至少部分浸渍于所述电解液中,所述正极极片包括正极集流体及正极活性层,所述正极活性层设置于所述正极集流体的表面,所述正极活性层包括正极活性材料及碳材料,在所述正极活性层中的碳材料的质量分数为B;其中,所述电池满足关系式:1.31wt%≤γB≤10.74wt%。该电池具有较高的动力学性能及安全性能。
Description
本申请要求于2024年03月26日提交中国专利局、申请号为2024103474408、申请名称为“电池、用电系统及储能系统”的中国专利申请的优先权,其全部内容通过引用结合在本申请中。
本申请涉及储能领域,具体涉及一种电池、用电系统及储能系统。
随着锂离子电池技术的不断发展,锂离子电池与铅酸、镉镍等其他类型的电池相比具有比容量大、无记忆效应、工作电压高、充电速度快、工作温度范围宽、循环寿命长、体积小、重量轻等优点。目前,锂离子电池已广泛应用于移动电话、笔记本电脑、电动汽车、储能电柜等领域,并且其应用范围越来越广泛。
随着储能行业的发展,对于锂离子电池快充及安全性能提出了更高的要求,然而现有的锂离子电池难以兼具动力学性能及安全性能。
发明内容
本申请实施例提供一种电池,其具有较高的动力学性能及安全性能。
第一方面,本申请提供一种电池,其包括:
电解液,所述电解液包括六氟磷酸锂及双氟磺酰亚胺锂,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比为γ;以及
正极极片,所述正极极片至少部分浸渍于所述电解液中,所述正极极片包括正极集流体及正极活性层,所述正极活性层设置于所述正极集流体的表面,所述正极活性层包括正极活性材料及碳材料,在所述正极活性层中的碳材料的质量分数为B;
其中,所述电池满足关系式:1.31wt%≤γB≤10.74wt%。
第二方面,本申请还提供一种用电系统,其包括:
用电设备,以及
储能装置,所述储能装置为所述用电设备进行供电,所述储能装置包括至少一个本申请实施例所述的电池。
第三方面,本申请还提供一种储能系统,其包括:
电能转换装置,所述电能转换装置用于将其它形式的能转换为电能;
储能装置,所述储能装置电连接所述电能转换装置,用于存储所述电能转换装置的所述电能,所述储能装置包括至少一个本申请实施例所述的电池;以及
用电负载,所述用电负载分别电连接所述电能转换装置及所述储能装置,用于利用电能转换装置或所述储能装置的所述电能进行工作。
本申请实施例的电池的电解液包括六氟磷酸锂及双氟磺酰亚胺锂,双氟磺酰亚胺锂的添加可以降低电池在过充阶段六氟磷酸根离子(PF6
-)的分解,从而减少电池的副反应,提高电池的安全性能,此外,减少六氟磷酸根离子(PF6
-)的分解,可以更好的维持电解液的电导率,使得电池具有更好的动力学性能。所述正极活性层包括正极活性材料及碳材料,正极
活性层中碳材料的加入可以提高正极极片的导电性能,从而进一步改善电池的动力学性能,但是,碳材料的含量过高,又会增加副反应,降低电池的安全性能,本申请实施例调控通过使得1.31wt%≤γB≤10.74wt%,通过六氟磷酸锂、双氟磺酰亚胺锂以及碳材料三者的含量的配合使用,从而使得电池具有较高的动力学性能的同时,又可以很好的减少电池的副反应,提高电池的安全性能。
为了更清楚地说明本申请实施例的技术方案,下面将对实施例中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本申请的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。
图1是本申请实施例提供的储能系统的应用场景图。
图2是本申请一实施例的储能系统的结构示意图。
图3是本申请一实施例的储能系统的电路框图。
图4是本申请一实施例的用电系统的局部透视结构示意图。
图5是本申请一实施例的储能装置的结构示意图。
图6是本申请一实施例的电池的结构示意图。
图7是本申请一实施例的电池沿图6中A-A方向的剖视结构示意图。
图8是本申请一实施例的正极极片沿图6中A-A方向的剖视结构示意图。
图9是本申请一实施例的负极极片沿图6中A-A方向的剖视结构示意图。
附图标记说明:
100-储能系统,110-电能转换装置,130-用电负载,200-储能装置,210-箱体,300-用电系统,310-用电设备,400-电池,410-正极极片,411-正极集流体,412-正极活性层,420-隔膜,430-负极极片,431-负极集流体,432-负极活性层,440-壳体。
为了使本技术领域的人员更好地理解本申请方案,下面将结合本申请实施例中的附图,对本申请实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本申请一部分实施例,而不是全部的实施例。基于本申请中的实施例,本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例,都属于本申请保护的范围。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别不同对象,而不是用于描述特定顺序。此外,术语“包括”和“具有”以及它们任何变形,意图在于覆盖不排他的包含。例如包含了一系列步骤或单元的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元,而是可选地还包括没有列出的步骤或单元,或可选地还包括对于这些过程、方法、产品或设备固有的其他步骤或单元。
下面将结合附图,对本申请实施例中的技术方案进行描述。
需要说明的是,为便于说明,在本申请的实施例中,相同的附图标记表示相同的部件,并且为了简洁,在不同实施例中,省略对相同部件的详细说明。
目前绿色电能的产生普遍依赖于光伏、风电、水势等,而风能和太阳能等普遍存在间歇性强、波动性大的问题,会造成电网不稳定,用电高峰电不够,用电低谷电太多,不稳定的电压还会对电力造成损害,因此可能因为用电需求不足或电网接纳能力不足,引发“弃风弃光”问题,要解决这些问题须依赖储能。即将电能通过物理或者化学的手段转化为其他形式
的能量存储起来,在需要的时候将能量转化为电能释放出来,简单来说,储能就类似一个大型“充电宝”,在光伏、风能充足时,将电能储存起来,在需要时释放储能的电力。
以电化学储能为例,本申请提供一种储能装置,储能装置内设有化学电池,主要是利用电池内的化学元素做储能介质,充放电过程伴随储能介质的化学反应或者变化,简单说就是把风能和太阳能产生的电能存在化学电池中,在外部电能的使用达到高峰时再将存储的电量释放出来使用,或者转移给电量紧缺的地方再使用。
目前的储能(即能量存储)应用场景较为广泛,包括发电侧储能、电网侧储能、可再生能源并网储能以及用户侧储能等方面,对应的储能装置的种类包括有:
(1)应用在电网侧储能场景的大型储能集装箱,其可作为电网中优质的有功无功调节电源,实现电能在时间和空间上的负荷匹配,增强可再生能源消纳能力,并在电网系统备用、缓解高峰负荷供电压力和调峰调频方面意义重大。
(2)应用在用户侧的工商业储能场景(银行、商场等)的中小型储能电柜以及应用在用户侧的家庭储能场景的户用小型储能箱,主要运行模式为“削峰填谷”。由于根据用电量需求在峰谷位置的电费存在较大的价格差异,用户有储能设备后,为了减少成本,通常在电价低谷期,对储能柜/箱进行充电处理;电价高峰期,再将储能设备中的电放出来进行使用,以达到节省电费的目的。另外,在边远地区,以及地震、飓风等自然灾害高发的地区,家用储能装置的存在,相当于用户为自己和电网提供了备用电源,免除由于灾害或其他原因导致的频繁断电带来的不便。
图1是本申请实施例提供的储能系统100的应用场景图。本申请图1实施例以用户侧储能中的户用储能场景为例进行说明,本申请储能装置200并不限定于户用储能场景。图2为本申请一实施例的储能系统100的结构示意图。图3为本申请一实施例的储能系统100的电路框图。
请参见图1至图3,本申请提供一种储能系统100,所述储能系统100为户用储能系统100,该储能系统100包括电能转换装置110、储能装置200以及用电负载130。所述电能转换装置110用于将其它形式的能转换为电能;所述储能装置200电连接所述电能转换装置110,用于存储所述电能转换装置110的所述电能;所述用电负载130分别电连接所述电能转换装置110及所述储能装置200,用于利用电能转换装置110或所述储能装置200的所述电能进行工作。可以理解地,所述电能转换装置110转换的电能一部分储存在所述储能装置200中,一部分用于为所述用电负载130供电,所述储能装置200用于储存电能并在电价高峰时供给用电负载130。所述储能系统100既能将其它形成的能转换为电能,又能将电能储存在储能装置200中,以供给用电负载130足够的电能。
可选地,所述电能转换装置110可将太阳能、光能、风能、热能、潮汐能、生物质能及机械能等中的至少一种转换为电能,为所述用电负载130及所述储能装置200提供稳定的电源。
可选地,所述电能转换装置110可以为但不限于为光伏板,所述光伏板可以在电价低谷时期将太阳能转换为电能,并储存在所述储能装置200。在其他实施例中,还可以为风能发电装置、热能发电装置、潮汐能发电装置、生物质能发电装置及机械能发电装置等中的至少一种。
可选地,所述储能装置200为一小型储能箱,可通过壁挂方式安装于室外墙壁。在其他实施例中,储能装置200还可以为大型的储能集装箱、应用于电子设备的电池等。
可选地,所述用电负载130可以为路灯或家用电器、机动车辆等,储能装置200用于储
存该电能并在电价高峰时供给路灯和家用电器进行使用,或者在电网断电/停电时进行供电。
可以理解的,储能装置200可包括但不限于包括单体电池、电池模组、电池包、电池系统等中的至少一种。单体电池可以为但不限于为圆柱电池、方形电池等中的至少一种。
可以理解地,本实施方式中附图示意仅仅为储能系统100的一种形态,不应当理解为对本申请提供的储能系统100的限定,也不应当理解为对本申请各个实施方式提供的储能装置200的限定。
请参见图4,图4为本申请一实施例的用电系统300的局部透视结构示意图。本申请实施例还提供一种用电系统300,其包括:用电设备310以及储能装置200,所述储能装置200为所述用电设备310进行供电。
本申请实施例的用电设备310可以为但不限于为手机、平板电脑、笔记本电脑、台式电脑、智能手环、智能手表、电子阅读器、游戏机等便携式电子设备。用电设备310还可以为汽车、卡车、轿车、货车、货车、动车、高铁、电动自动车等交通工具。此外,用电设备310还可以为各种家用电器例如冰箱、电灯、空调等。可以理解地,本申请附图示意的用电设备310仅仅是用电设备310的其中一种形态,不应当理解为对本申请提供的用电设备310的限定。
请参见图5,本申请实施例还提供一种储能装置200,该储能装置200包括箱体210及多个电池400,所述多个电池400堆叠设置且收容于所述箱体210内。
可选地,电池400可以为但不限于为锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池、储能电池等。
术语“多个”指大于或等于两个。
可以理解地,储能装置200的多个电池400可以相互并联;或者相互串联;或者部分并联,部分串联(换言之,混联),对于同一个储能装置200的多个电池400的连接方式,本申请不作具体限定。
可以理解地,箱体210具有容置腔(图未示),多个电池400收容于容置腔内。在一些实施例中,每个容置腔收容一个电池400。在另一些实施例中,每个容置腔收容多个电池400。
请参见图6及图7,本申请实施例还提供一种电池400,其包括电解液、正极极片410、隔膜420及负极极片430。所述正极极片410至少部分浸渍于所述电解液中;所述隔膜420位于所述正极极片410的一侧,以及所述负极极片430设置于所述隔膜420背离所述正极极片410的一侧且至少部分浸渍于所述电解液中。
请一并参见图8,在一些实施例中,所述电解液包括电解质盐,所述电解质盐包括六氟磷酸锂(LiPF6)及双氟磺酰亚胺锂(LiFSI),所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比为γ;所述正极极片410包括正极集流体411及正极活性层412,所述正极活性层412设置于所述正极集流体411的表面,所述正极活性层412包括正极活性材料及碳材料,在所述正极活性层412中的碳材料的质量分数为B;其中,所述电池400满足关系式:1.31wt%≤γB≤10.74wt%。
可以理解地,所述正极极片410、隔膜420及负极极片430依次层叠设置组成电极组件。所述电极组件可以为但不限于为卷绕式结构、叠片式结构等,本申请对此不作具体限定。
需要说明的是,正极极片410与负极极片430可以统称为电极极片,换而言之,电极极片包括正极极片410及负极极片430。
可选地,所述电池400还包括壳体440,所述壳体440用于收容所述电解液、正极极片410、隔膜420及所述的负极极片430。
可以理解地,所述正极活性层412可以覆盖所述正极集流体411的一个表面或也可以覆盖所述正极集流体411的相对两个表面。
具体地,γB的取值可以为但不限于为1.31wt%、1.5wt%、2wt%、3wt%、4wt%、5wt%、6wt%、7wt%、8wt%、9wt%、10wt%、11wt%、10.74wt%等。当γB太小时,则可能是六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过小或者在所述正极活性层412中的碳材料的质量分数B过小;当六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过小时,表明电解液中六氟磷酸锂的含量过小,双氟磺酰亚胺锂的含量过高,当电池400处于高温、高电压的工作环境时,过高含量的双氟磺酰亚胺锂,容易腐蚀铝箔,从而破坏正极极片410,降低电池400的寿命,影响电池400的正常工作,且增加了电解液的成本;当所述正极活性层412中的碳材料的质量分数B过小时,则容易使得正极极片410的导电子能力不足,正极极片410的阻抗增加,降低了电池400的倍率性能和循环性能。当γB太大时,则可能是六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过大或者在所述正极活性层412中的碳材料的质量分数B过大;当六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过大时,表明电解液中六氟磷酸锂的含量过高,双氟磺酰亚胺锂的含量过小,则电池400在过充阶段,六氟磷酸根离子(PF6
-)容易发生分解产生酸,过多的副反应,容易使得电池400温度升高,降低了电池400的安全性能,此外,六氟磷酸根离子的分解降低了电解液的电导率,从而降低了电池400的动力学性能;当所述正极活性层412中的碳材料的质量分数B过大时,则降低了正极极片410的能量密度,此外,当电池400过充时(例如过充电压为4.8V时),会加剧电解液与正极活性层412的表面的副反应,容易使得电池400温度升高,降低了电池400的安全性能。本实施例通过使得1.31wt%≤γB≤10.74wt%,从而使得电池400的电解液具有较高的电导率,电池400具有较高的动力学性能,此外,又可以降低电池400内部的副反应特别是过充时的副反应,从而降低电池400在过充阶段温度,大大提高了电池400的安全性能。
进一步地,所述电池400满足关系式:1.8wt%≤γB≤10wt%。当γB处于这个范围时,可以更好的使得电池400具有较高的动力学性能的同时,又具有减少的副反应,从而具有较高的安全性能。
又进一步地,所述电池400满足关系式:2wt%≤γB≤9wt%。当γB处于这个范围时,可以更好的使得电池400具有较高的动力学性能的同时,又具有减少的副反应,从而具有较高的安全性能。
本申请实施例的电池400的电解液包括六氟磷酸锂及双氟磺酰亚胺锂,双氟磺酰亚胺锂的添加可以减少电池400在过充阶段六氟磷酸根离子(PF6
-)的分解,从而减少电池400的副反应,提高电池400的安全性能,此外,减少六氟磷酸根离子(PF6
-)的分解,可以更好的维持电解液的电导率,使得电池400具有更好的动力学性能。所述正极活性层412包括正极活性材料及碳材料,正极活性层412中碳材料的加入可以提高正极极片410的导电性能,从而进一步改善电池400的动力学性能,但是,碳材料的含量过高,又会增加副反应,降低电池400的安全性能,本申请实施例调控通过使得1.31wt%≤γB≤10.74wt%,通过六氟磷酸锂、双氟磺酰亚胺锂以及碳材料三者的含量的配合使用,从而使得电池400具有较高的动力学性能的同时,又可以很好的减少电池400的副反应,提高电池400的安全性能。
可选地,所述正极集流体411可以为但不限于为铝片。
可选地,正极活性材料可以为但不限于为磷酸铁锂。
在一些实施例中,所述正极活性层412中,碳材料的质量分数B的范围为:1.073wt%≤B≤1.653wt%。具体地,在正极活性层412中,碳材料的质量分数B可以为但不限于为
1.073wt%、1.1wt%、1.15wt%、1.2wt%、1.25wt%、1.3wt%、1.35wt%、1.4wt%、1.45wt%、1.5wt%、1.55wt%、1.6wt%、1.653wt%等。碳材料有助于导电网络形成,增加电子传输路径,改善正极极片410的动力学,当所述正极活性层412中的碳材料的质量分数B过小时,则容易使得正极极片410的导电子能力不足,正极极片410的阻抗增加,降低了电池400的倍率性能和循环性能。当所述正极活性层412中的碳材料的质量分数B过大时,则降低了正极极片410的能量密度,此外,当电池400过充时(例如过充电压为4.8V时),会加剧电解液与正极活性层412的表面的副反应,容易使得电池400温度升高,降低了电池400的安全性能。本实施例通过使得碳材料的质量分数B的范围为:1.073wt%≤B≤1.653wt%,从而使得电池400的电解液具有较高的导电子能力及较低的阻抗,提高了电池400的倍率性能和循环性能,此外,又可以使得电池400在过充时具有较少的副反应,降低了电池400的过充温度,从而降低了电池400的安全性能。
进一步地,所述正极活性层412中,碳材料的质量分数B的范围为:1.2wt%≤B≤1.6wt%。当所述正极活性层412中的碳材料的质量分数B处于这个范围时,可以使得电池400的电解液具有更高的导电子能力及较低的阻抗,更好的提高电池400的倍率性能和循环性能,此外,又可以使得电池400在过充时具有更少的副反应,降低了电池400的过充温度,从而更好的降低电池400的安全性能。
在一些实施例中,所述碳材料包括碳包覆层(也可以称为包覆碳)及导电碳,所述碳包覆层包裹于所述正极活性材料的表面,所述导电碳分散于正极活性层412中;在所述正极活性层412中,所述碳包覆层与所述导电碳的质量比的范围为:2.57≤B1/B2≤4.5。
具体地,在所述正极活性层412中,所述碳包覆层与所述导电碳的质量比B1/B2可以为但不限于为2.57、2.8、3.0、3.2、3.4、3.6、3.8、4.0、4.2、4.4、4.5等。
当所述碳包覆层与所述导电碳的质量比B1/B2太小时,则会恶化正极极片410的正极活性层412的界面动力学,使得锂离子脱出及嵌入速率降低,界面极化增大;当所述碳包覆层与所述导电碳的质量比B1/B2太大时,则使得正极活性层412的克容量发挥不足,能量密度有所降低,此外,还会恶化正极极片410在高电压下电解液与碳包覆层界面的副反应。
可选地,在所述正极活性层412中,所述碳包覆层的质量分数B1的范围为:0.77wt%≤B1≤1.35wt%。
具体地,在所述正极活性层412中,所述碳包覆层的质量分数B1可以为但不限于为0.77wt%、0.8wt%、0.87wt%、0.9wt%、0.95wt%、1.04wt%、1.1wt%、1.15wt%、1.20wt%、1.25wt%、1.30wt%、1.35wt%等。当在所述正极活性层412中,所述碳包覆层的质量分数B1太低,则碳包覆层无法完全包覆正极活性材料,使得部分正极活性材料与电解液直接接触,增加了电解液与正极活性层412之间的副反应,从而增加了电解液的消耗,降低了电池400的循环容量保持率;此外,碳包覆层也影响正极活性层412界面导电网络的构建,所述碳包覆层的质量分数过低也会恶化导电性能,影响动力学。
可选地,在所述正极活性层412中,所述导电碳的质量分数B2的范围为:0≤B2≤0.3wt%。具体地,在所述正极活性层412中,所述导电碳的质量分数B2可以为但不限于为0.05wt%、0.1wt%、0.15wt%、0.2wt%、0.25wt%、0.3wt%等。在所述正极活性层412中,所述导电碳的质量分数B2太小,则粘结剂间的正极活性材料(如磷酸铁锂)的导电网络搭建不足,降低了正极活性层412的电子电导率,从而降低了正极活性层412的动力学性能;在所述正极活性层412中,所述导电碳的质量分数B2太大,则正极活性层412在制浆过程中粘度过大,增加正极活性层412涂布的难度,影响正极活性层412克容量的发挥。
可选地,导电碳可以为但不限于为导电炭黑、乙炔黑、碳纳米管、碳纤维、石墨烯等中的至少一种。
可选地,碳包覆层可以由碳源通过碳热还原法烧结得到。
可选地,所述碳源可以为但不限于为葡萄糖、蔗糖、淀粉、高分子碳源如PEG等中的至少一种。
可选地,所述正极活性层412还包括第一粘结剂及第一增稠剂。
可选地,第一粘结剂可以为但不限于为聚偏氟乙烯(Polyvinylidene Fluoride,简称PVDF)、聚酰胺(Polyamide,简称PA)、聚丙烯腈(Polyacrylonitrile,简称PAN)、聚丙烯酸酯(Polyacrylate)、聚乙烯醚(Polyvinylether)、聚甲基丙烯酸甲酯(Polymethyl Methacrylate,简称PMMA)、聚六氟丙烯(Polyhexafluoropropylene)、丁苯橡胶(Polymerized Styrene Butadiene Rubber,简称SBR)等中的至少一种。
可选地,在所述正极活性层412中,所述第一粘结剂的质量分数的范围为2wt%至4wt%。具体地,在所述正极活性层412中,所述第一粘结剂的质量分数可以为但不限于为2wt%、2.5wt%、3wt%、3.5wt%、4wt%等。第一粘结剂的质量分数太小,则正极活性层412容易粉化或掉渣;第一粘结剂的质量分数太大,降低了正极极片410的能量密度。
可选地,第一增稠剂可以为但不限于为羧甲基纤维素钠(简称CMC)、聚丙烯酰胺(PAM)及聚甲基丙烯酸酯(PMA)等中的至少一种。
可选地,隔膜420可以为但不限于为聚丙烯膜(简称PP膜)、聚乙烯膜(简称PE膜)、陶瓷隔膜420等中的至少一种。
可选地,所述隔膜420的厚度为14μm至18μm,具体地,所述隔膜420的厚度可以为但不限于为14μm、14.5μm、15μm、15.5μm、16μm、16.5μm、17μm、17.5μm及18μm等。
在一些实施例中,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比γ的范围为:1.22≤γ≤6.5。具体地,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比γ可以为但不限于为1.22、1.5、2、2.5、3、3.5、4、4.5、5、5.5、6、6.5等。当六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过小时,表明电解液中六氟磷酸锂的含量过小,双氟磺酰亚胺锂的含量过高,当电池400处于高温、高电压的工作环境时,过高含量的双氟磺酰亚胺锂,容易腐蚀铝箔,从而破坏正极极片410,降低电池400的寿命,影响电池400的正常工作,且增加了电解液的成本;当六氟磷酸锂与双氟磺酰亚胺锂的质量比γ过大时,表明电解液中六氟磷酸锂的含量过高,双氟磺酰亚胺锂的含量过小,则电池400在过充阶段,六氟磷酸根离子(PF6
-)容易发生分解产生酸,过多的副反应,容易使得电池400温度升高,降低了电池400的安全性能,此外,六氟磷酸根离子的分解降低了电解液的电导率,从而降低了电池400的动力学性能。当六氟磷酸锂与双氟磺酰亚胺锂的质量比γ的范围为:1.22≤γ≤6.5时,则可以使得电池400具有较低的成本及较高的使用寿命,同时又可以使得电池400具有较高的安全性能及动力学性能。
进一步地,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比γ的范围为:1.5≤γ≤6。当所述电解液中六氟磷酸锂与双氟磺酰亚胺锂的质量比γ处于这个范围时,既可以使得电池400具有较低的成本,且具有较高的使用寿命的同时,又可以使得电池400具有较好的耐过充性能、安全性能及动力学性能。
在一些实施例中,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M的范围为0.7mol/L≤M≤1.4mol/L。所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M
可以为但不限于为0.7mol/L、0.8mol/L、0.9mol/L、1.0mol/L、1.1mol/L、1.2mol/L、1.3mol/L、1.4mol/L等。六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M太小,则电解液中游离的离子浓度过少,降低了电解液的电导率,从而降低了电池400的动力学性能;六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M太大,则容易存在一部分电解质盐未解离,且会使得电解液的粘度增加,反而降低了电解液的电导率,也会降低电池400的动力学性能。当所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M的范围为0.7mol/L≤M≤1.4mol/L时,可以使得电解液具有较高的电导率,从而使得电池400具有较好的动力学性能。
进一步地,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M的范围为0.8mol/L≤M≤1.3mol/L。当所述电解液中六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M处于这个范围时,可以使得电解液具有更好的电导率,从而使得电池400具有更好的动力学性能。
在一些实施例中,所述电解液还包括含硫添加剂。含硫添加剂可以在正极极片410形成硫酸锂盐或烷基硫酸锂盐,可以进一步稳固正极极片410的固体电解质界面膜(Solid Electrolyte Interface,简称SEI膜),且可以使得正极极片410的固体电解质界面膜更薄,更好的降低正极极片410的阻抗,从而降低正极极片410的高温产热量,提高电池400的安全性能。
可选地,含硫添加剂可以为但不限于为正极含硫添加剂。
可选地,在所述电解液中,所述含硫添加剂的质量分数w1的范围为0.1wt%≤w1≤1wt%。具体地,在所述电解液中,所述含硫添加剂的质量分数w1可以为但不限于为0.1wt%、0.2wt%、0.3wt%、0.4wt%、0.5wt%、0.6wt%、0.7wt%、0.8wt%、0.9wt%、1wt%等。在所述电解液中,所述含硫添加剂的质量分数w1太低,则对于正极极片410的界面膜的稳定有限,不能很好的提高电池400的安全性能;在所述电解液中,所述含硫添加剂的质量分数w1太高,则在高温的下,含硫添加剂容易分解产酸,破坏正极极片410的界面膜,使得正极极片410的正极活性层412直接与电解液接触,增加了正极活性层412与电解液的副反应,从而增加了电解液的消耗,降低了电池400的循环容量保持率。当电解液中含硫添加剂的质量分数为0.1wt%≤w1≤1wt%时,可以更好的提高电池400的安全性能的同时,又可以使得电池400保持较高的循环容量保持率。
在一些实施例中,所述含硫添加剂包括甲烷二磺酸亚甲酯(MMDS)、硫酸亚乙酯(DTD)、三(三甲基硅基)亚磷酸酯(TMSP)、丙烯磺酸内酯(PST)、丁基磺酸内酯(BS)、亚硫酸丙烯酯(PS)中的至少一种。在本实施例中,采用这些含硫添加剂可以更好的稳定正极极片410的界面膜,降低正极极片410的阻抗,减少正极极片410的高温产热量,提高电池400的安全性能,此外,这些物质在电池400处于高温下,更不易分解产酸,可以更好的减少高温是电解液的消耗,从而使得电池400保持在较高的循环容量保持率。
在一些实施例中,所述电解液还包括锂盐添加剂。可以补充电解液中的锂离子,此外,锂盐添加剂可以改善正极极片410或负极极片430的阻抗,提高电池400的动力学性能。
可选地,在所述电解液中,所述锂盐添加剂的质量分数w2为0.2wt%≤w2≤2wt%。具体地,锂盐添加剂的质量分数w2可以为但不限于为0.2wt%、0.4wt%、0.6wt%、0.8wt%、1.0wt%、1.2wt%、1.4wt%、1.6wt%、1.8wt%、2wt%等。所述锂盐添加剂的质量分数w2太小,则对于正极极片410或负极极片430阻抗的降低有限,难以起到增加正极极片410或负极极片430的动力学性能;所述锂盐添加剂的质量分数w2太大,则由于锂盐添加剂的溶解度有限,当锂盐添加剂的浓度到一定程度后,对于正极极片410或负极极片430的动力学性能不会再有
提升,但是会大大增加电池400的成本。当锂盐添加剂的质量分数w2为0.2wt%≤w2≤2wt%时,可以提高正极极片410或负极极片430的动力学性能的同时,又可以使得电池400具有较低的成本。
可选地,锂盐添加剂包括双(三氟甲烷磺酰)亚胺锂(LiTFSI)、二氟磷酸锂(LiPO2F2)、二氟草酸硼酸锂(LiODFB)、二氟草酸磷酸锂中的至少一种。在本实施例中,采用这几种锂盐添加剂可以更好的在正极极片410或负极极片430的表面形成无机盐结构或成膜,从而降低正极极片410或负极极片430的阻抗,更好的提高正极极片410或负极极片430的动力学性能。例如二氟磷酸锂可以在负极极片430形成氟化锂等无机盐结构,可以降低负极极片430的阻抗,提高负极极片430的动力学性能。又例如:二氟草酸硼酸锂可以在正极极片410与负极极片430的表面成膜,从而降低正极极片410与负极极片430的阻抗,提高正极极片410与负极极片430的动力学性能。
可选地,电解液还包括有机溶剂,所述有机溶剂包括环状碳酸酯、链状碳酸酯中的至少一种。环状碳酸酯介电常数高、离子电导率高,能够在负极极片430的表面形成稳定的SEI膜,但其粘度较大。链状碳酸酯粘度比环状碳酸酯低,电化学稳定性更好,能够提高电解液低温性能。因此,采用环状碳酸酯与链状碳酸酯混合溶剂时,既可以使得电解液具有较为适合的粘度及低温稳定性,又可以使得使用该电解液的电池400可以进行更好的成膜。
可选地,所述环状碳酸酯可以包括但不限于包括碳酸乙烯酯(简称EC)、碳酸丙烯酯(简称PC)等中的至少一种。碳酸乙烯酯的介电常数远大于碳酸丙烯酯的介电常数,碳酸乙烯酯可以更好的促进SEI膜的形成。
可选地,所述链状碳酸酯可以包括但不限于包括碳酸二甲酯(简称DMC)、碳酸二乙酯(简称DEC)、碳酸甲乙酯(简称EMC)等中的至少一种。碳酸二甲酯(简称DMC)与碳酸二乙酯(简称DEC)可以更好的提高电解液的电导率和可溶性。
可选地,在所述电解液中,所述有机溶剂的质量分数为60wt%至85wt%。具体地,可以为但不限于为60wt%、65wt%、70wt%、75wt%、80wt%、85wt%等。
可选地,所述有机溶剂还包括乙酸乙酯、乙酸丙酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、2,2-二氟乙基乙酸酯中的至少一种。
可选地,所述电解液还包括成膜添加剂,当所述电解液应用于锂离子电池400时,所述成膜添加剂可用于促进所述正极极片410及负极极片430中的至少一个的界面膜的形成且维持所述界面膜的稳定性。
可选地,所述成膜添加剂包括氟代碳酸乙烯酯(FEC)、硫酸乙烯酯(PST)、碳酸亚乙烯酯(VC)、乙烯基碳酸乙烯酯(VEC)、硫三(三甲基硅烷)磷酸酯、三(三甲基硅烷)硼酸酯、己二腈、丁二腈、1,3,6-己无法烷三腈中的至少一种。
可选地,所述成膜添加剂的质量分数的范围为1%至3%。具体地,所述成膜添加剂的质量分数可以为但不限于为1%、1.2%、1.4%、1.5%、1.6%、1.7%、1.8%、1.9%、2%、2.1%、2.2%、2.3%、2.4%、2.5%、2.6%、2.7%、2.8%、2.9%、3%等。
请参见图9,可选地,所述负极极片430包括负极集流体431以及负极活性层432,所述负极活性层432设置于所述负极集流体431的表面。可以理解地,所述负极活性层432可以覆盖所述负极集流体431的一个表面或相对的两个表面。
可选地,负极集流体431可以为但不限于为铜片。
可选地,所述负极活性层432包括负极活性材料、负极导电剂、第二粘结剂及第二增稠剂。
可选地,负极活性材料可以为但不限于为石墨。可选地,石墨可以为天然石墨或人造石墨,本申请对此不作具体限定。
可选地,所述负极导电剂可以为但不限于为导电炭黑(简称SP)、乙炔黑、碳纳米管、碳纤维、石墨烯等中的至少一种。
可选地,第二粘结剂可以为但不限于为聚偏氟乙烯(Polyvinylidene Fluoride,简称PVDF)、聚酰胺(Polyamide,简称PA)、聚丙烯腈(Polyacrylonitrile,简称PAN)、聚丙烯酸酯(Polyacrylate)、聚乙烯醚(Polyvinylether)、聚甲基丙烯酸甲酯(Polymethyl Methacrylate,简称PMMA)、聚六氟丙烯(Polyhexafluoropropylene)、丁苯橡胶(Polymerized Styrene Butadiene Rubber,简称SBR)等中的至少一种。
可选地,在所述负极活性层432中,所述第二粘结剂的质量分数的范围为2wt%至4wt%。具体地,在所述负极活性层432中,所述第二粘结剂的质量分数可以为但不限于为2wt%、2.5wt%、3wt%、3.5wt%、4wt%等。第二粘结剂的质量分数太小,则负极活性层432容易粉化或掉渣;第二粘结剂的质量分数太大,降低了负极极片430的能量密度。
可选地,第二增稠剂可以为但不限于为羧甲基纤维素钠(简称CMC)、聚丙烯酰胺(PAM)及聚甲基丙烯酸酯(PMA)等中的至少一种。
经测试,本申请实施例的电池400在1C放电倍率下,电池400的循环容量保持率大于或等于95.32%,具体地,可以但不限于为95.32%、96%、97%、98%、99%等。本申请实施例的电池400在2C放电倍率下,电池400的循环容量保持率大于或等于88.13%,具体地,可以但不限于为88.13%、90%、91%、92%、93%、94%、95%、95.32%、96%、97%、98%、99%等。
以下通过具体实施例对本申请的电池400做进一步的描述。
实施例1至实施例23、对比例1至对比例5
各实施例及对比例的电池400的制备方法包括:
(1)正极极片410的制备:将质量比97.4:0.3:2.3为正极颗粒(正极颗粒包括磷酸铁锂正极活性材料及包覆于所述磷酸铁锂表面的碳包覆层)、导电炭黑SP(导电碳)、及PVDF(第一粘结剂)进行干混,混合均匀后,加入至N-甲基吡咯烷酮(简称NMP)溶剂进行搅拌捏合,捏合的固含量为72%至74%;接着持续加入N-甲基吡咯烷酮进行高速分散,再经过调粘、真空慢搅除泡、过滤等工序,形成粘度、细度均一的正极浆料;将正极浆料涂布于铝箔(正极集流体411)上,控制正极浆料的涂覆厚度为0.5g/1540.25mm2至0.6g/1540.25mm2;接着通过烘烤、辊压、分切、裁片制成正极极片410;同时可通过刮取正极极片410料区粉末使用碳硫分析仪进行正极极片410碳材料含量检测,各实施例及对比例的详细数据请参见下表1。
(2)负极极片430的制备:将负极活性材料人造石墨、导电炭黑SP(第二导电剂)、羧甲基纤维素钠CMC(第二增稠剂)预设质量比混合,加入一定量去离子水搅拌,加入丁苯橡胶(SBR第二粘结剂)搅拌分散,使得人造石墨、导电炭黑、羧甲基纤维素钠及丁苯橡胶的质量比为96.9:0.1:1:2;经真空慢搅除泡、过滤等工序,形成粘度、细度均一的负极浆料;然后将负极浆料涂布在铜箔(负极集流体431)上,使负极浆料的涂附厚度控制在0.24g/1540.25mm2至0.3g/1540.25mm2;接着通过烘烤、辊压、分切、裁片等工序制成负极极片430。
(3)电解液配置:碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)及碳酸乙烯酯(EC)三种溶剂用分子筛除水,以使溶剂的水分低于10ppm;在水分含量≤1ppm的氩气气氛手套箱中,将碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸乙烯酯(EC)按照一定配比进行混合得
到混合溶剂,之后将干燥的电解质盐六氟磷酸锂与双氟磺酰亚胺锂溶解到混合溶剂中,搅拌至完全溶解均匀,加入氟代碳酸乙烯酯(FEC)、碳酸亚乙烯酯(VC)甲烷二磺酸亚甲酯(含硫添加剂MMDS)等混合均匀后制得电解液。
其中,实施例1至实施例16、实施例20至实施例23、及对比例1至对比例7的电解液中,碳酸二甲酯、碳酸甲乙酯、碳酸乙烯酯的质量比1:1:1。实施例17至实施例19中碳酸二甲酯、碳酸甲乙酯、碳酸乙烯酯的质量比分别为1.1:0.9:1、0.9:1.1:0.9、1:1.1:0.9。
其中,实施例1至实施例19、实施例23、及对比例1至对比例7的电解液中,氟代碳酸乙烯酯的添加量均为1wt%,碳酸亚乙烯酯的添加量均为2wt%、甲烷二磺酸亚甲酯的添加量均为0.5wt%。实施例20至实施例22的电解液中,氟代碳酸乙烯酯的添加量均为1.01wt%,碳酸亚乙烯酯的添加量均为2.01wt%、甲烷二磺酸亚甲酯的添加量均为0.51wt%。
其中,实施例1至实施例22、及对比例1至对比例7的电解液中,所述六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度为1mol/L。实施例23的电解液中,所述六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度为1.01mol/L。
各实施例及对比例的六氟磷酸锂和双氟磺酰亚胺锂的质量比γ如下表1所示。
(4)提供隔膜420:以16μm的聚乙烯薄膜为隔膜420。
(5)电池400的组装:将正极极片410、隔膜420、负极极片430依次层叠组成电极组件,将电极组件进行卷绕之后得到裸电芯,焊接极耳后将电芯装配到外包装中,注入制备得到的电解液后,对电芯进行封装、静置、化成、整形、容量测试等,最终制备得到3.2Ah的电池400。
对比例6
对比例6与实施例13的不同之处在于,本对比例的正极活性层412的碳材料仅包括碳包覆层,不具有导电碳。
对比例7
对比例7与实施例1的不同之处在于,本对比例的正极活性层412的碳材料仅包括碳包覆层,不具有导电碳。
对各实施例及对比例的电池400进行过充测试及不同倍率下的放电容量保持率测试。各实施例及对比例的电池400的性能参数如下表1所示。
(1)电池400的过充测试:取上述制得的新鲜电池400,在电池400的表面贴上感温线以监控电池400在过充过程中的温度。先对电池400进行预处理,在45℃条件下,使用1C的倍率循环充放电3圈,接着在常温下以1C的倍率循环充放电一圈,再以1C恒流充电至3.65V,接着在3.65V恒压充电至0.05C截止;接着以1C电流对电池400进行持续充电,充电到5.475V(满电电压的1.5倍,即1.5×3.65V)或者充电时长达到1h结束充电,结束充电后观察1h,监控电池400表面的温度。各实施例及对比例的过充温度及过充时间如下表1所示。“过充时间”指电池400在满电(电压为3.65V)后,继续充电至电压为满电电压的1.5倍(5.475V)所需要的时间。
(2)电池400的倍率性能测试:使电池400在2.5-3.65V电压范围内,进行0.5C恒电流充电,以0.05C为截止电流,测试不同放电倍率(例如1C放电倍率、2C放电倍率)下电池400的放电容量保持率。
放电容量保持率计算公式为:第n次循环后的容量保持率=(第n次循环后的放电容量/循环第一圈的放电容量)×100%。
表1各实施例及对比例的电池400性能参数
由表1中实施例1至实施例16的测试数据可知,本申请实施例的电池400当满足1.31wt%≤γB≤10.74wt%时,在1C放电倍率下,电池400的循环容量保持率均在95.32%以上,在2C放电倍率下,电池400的循环容量保持率均在88.13%以上,本申请实施例的电池400在1C放电倍率下及2C放电倍率下均具有较高的循环容量保持率,这说明本申请实施例的电池400具有较好的动力学性能。
此外,由表1中实施例1至实施例16的测试数据还可知,本申请实施例的电池400当满足1.31wt%≤γB≤10.74wt%时,在电池400过充(过充至满电电压的1.5倍电压)时,电池400的表面的过充温度小于或等于79℃,具有较低的过充温度;各实施例的过充时间均小于或等于13.9min,具有较短的过充时间,这说明电池400在过充阶段产生的热量较少,具有更好的耐过充性能,从而具有更好的安全性能。
由实施例1、实施例5、实施例9及实施例13的测试结果可知,本申请实施例的电池400当满足1.31wt%≤γB≤10.74wt%时,本申请实施例的电池400在1C放电倍率下及2C放电倍率下均具有较高的循环容量保持率,具有较好的倍率性能。由对比例3的测试结果可知,当γ<1.22,γB<1.31wt%时,虽然电池400在1C放电倍率时仍具有较高的循环容量保持率,但是在2C放电倍率时循环容量保持率明显下降。由对比例5的测试结果可知,当γ>6.5时,虽然电池400在1C放电倍率时仍具有较高的循环容量保持率,但是在2C放电倍率时循环容量保持率也明显下降。此外,由对比例4可知,当γ>6.5且γB>10.74wt%时,相较于对比例5,对比例4在1C放电倍率的循环容量保持率及2C放电倍率的循环容量保持率均有所下降。此外,由对比例4及对比例5还可知,当γ>6.5,或者γ>6.5且γB>10.74wt%时,电池400的过充温度明显增加,过充时间明显变长,这说明电池400的耐充性能降低,安全性能降低。
由实施例1至实施例4的测试结果可知,当γ的数值固定且1.073wt%≤B≤1.653wt%时,随着碳材料的含量(即B=B1+B2)增加,电池400在1C放电倍率下的循环容量保持率及2C放电倍率下的循环容量保持率均有所增加。
由实施例1和对比例7的测试结果可知,当正极活性层412的碳材料均为碳包覆层,不具有导电炭时(即对比例7),则电池400在1C放电倍率下的循环容量保持率及2C放电倍率下的循环容量保持率基本不变。此外,电池400的过充温度明显升高,且过充时间也增加,说明电池400的抗过充性能降低,安全性能降低。
由实施例13和对比例6的测试结果可知,当正极活性层412的碳材料均为碳包覆层,不具有导电炭时(即对比例6),则电池400在1C放电倍率下的循环容量保持率及2C放电倍率下的循环容量保持率基本不变。此外,电池400的过充温度明显升高,且过充时间也增加,说明电池400的抗过充性能降低,安全性能降低。
由实施例5、实施例17至实施例19的测试结果可知,当γ、B1、B2及B等相同时,仅仅改变电解液的溶剂配比,对于电池在1C放电倍率的循环容量保持率及2C放电倍率的循环容量保持率几乎没有变化,过充温度及过充时间也变化很小。
由实施例5、实施例20至实施例22的测试结果可知,当γ、B1、B2及B等相同时,仅仅改变电解液的成膜添加剂的配比,对于电池在1C放电倍率的循环容量保持率及2C放电倍率的循环容量保持率几乎没有变化,过充温度及过充时间也变化很小。
由实施例5、实施例20至实施例22的测试结果可知,当γ、B1、B2及B等相同时,仅仅改变电解液中所述六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度,对于电池在1C放电倍率的循环容量保持率及2C放电倍率的循环容量保持率几乎没有变化,过充温度及过充时间也变化很小。
在本申请中提及“实施例”“实施方式”意味着,结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现所述短语并不一定均是指相同的实施例,也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是,本申请所描述的实施例可以与其它实施例相结合。此外,还应该理解
的是,本申请各实施例所描述的特征、结构或特性,在相互之间不存在矛盾的情况下,可以任意组合,形成又一未脱离本申请技术方案的精神和范围的实施例。
最后应说明的是,以上实施方式仅用以说明本申请的技术方案而非限制,尽管参照以上较佳实施方式对本申请进行了详细说明,本领域的普通技术人员应当理解,可以对本申请的技术方案进行修改或等同替换都不应脱离本申请技术方案的精神和范围。
Claims (10)
- 一种电池,其中,包括:电解液,所述电解液包括六氟磷酸锂及双氟磺酰亚胺锂,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比为γ;以及正极极片,所述正极极片至少部分浸渍于所述电解液中,所述正极极片包括正极集流体及正极活性层,所述正极活性层设置于所述正极集流体的表面,所述正极活性层包括正极活性材料及碳材料,在所述正极活性层中的碳材料的质量分数为B;其中,所述电池满足关系式:1.31wt%≤γB≤10.74wt%。
- 根据权利要求1所述的电池,其中,所述正极活性层中,碳材料的质量分数B的范围为:1.073wt%≤B≤1.653wt%。
- 根据权利要求2所述的电池,其中,所述碳材料包括碳包覆层及导电碳,所述碳包覆层包裹于所述正极活性材料的表面,所述导电碳分散于正极活性层中;在所述正极活性层中,所述碳包覆层与所述导电碳的质量比的范围为:2.57≤B1/B2≤4.5。
- 根据权利要求1所述的电池,其中,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的质量比γ的范围为:1.22≤γ≤6.5。
- 根据权利要求1所述的电池,其中,所述电解液中,六氟磷酸锂与双氟磺酰亚胺锂的总摩尔浓度M的范围为0.7mol/L≤M≤1.4mol/L。
- 根据权利要求1所述的电池,其中,所述电解液还包括含硫添加剂,所述含硫添加剂的质量分数w1的范围为0.1wt%≤w1≤1wt%。
- 根据权利要求6所述的电池,其中,所述含硫添加剂包括甲烷二磺酸亚甲酯、硫酸亚乙酯、三(三甲基硅基)亚磷酸酯、丙烯磺酸内酯、丁基磺酸内酯、亚硫酸丙烯酯中的至少一种。
- 根据权利要求1-7任一项所述的电池,其中,所述电解液还包括锂盐添加剂,在所述电解液中,所述锂盐添加剂的质量分数w2为0.2wt%≤w2≤2wt%;锂盐添加剂包括双(三氟甲烷磺酰)亚胺锂、二氟磷酸锂、二氟草酸硼酸锂、二氟草酸磷酸锂中的至少一种。
- 一种用电系统,其中,包括:用电设备,以及储能装置,所述储能装置为所述用电设备进行供电,所述储能装置包括至少一个权利要求1-8任一项所述的电池。
- 一种储能系统,其中,包括:电能转换装置,所述电能转换装置用于将其它形式的能转换为电能;储能装置,所述储能装置电连接所述电能转换装置,用于存储所述电能转换装置的所述电能,所述储能装置包括至少一个权利要求1-8任一项所述的电池;以及用电负载,所述用电负载分别电连接所述电能转换装置及所述储能装置,用于利用电能转换装置或所述储能装置的所述电能进行工作。
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| CN117954692A (zh) * | 2024-03-26 | 2024-04-30 | 深圳海辰储能科技有限公司 | 电池、用电系统及储能系统 |
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