WO2022161270A1 - 锂离子电池、电池模块、电池包、及用电装置 - Google Patents

锂离子电池、电池模块、电池包、及用电装置 Download PDF

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WO2022161270A1
WO2022161270A1 PCT/CN2022/073161 CN2022073161W WO2022161270A1 WO 2022161270 A1 WO2022161270 A1 WO 2022161270A1 CN 2022073161 W CN2022073161 W CN 2022073161W WO 2022161270 A1 WO2022161270 A1 WO 2022161270A1
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negative electrode
lithium
ion battery
battery
lithium ion
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PCT/CN2022/073161
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English (en)
French (fr)
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邹海林
陈培培
彭畅
梁成都
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宁德时代新能源科技股份有限公司
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Priority to EP22745145.7A priority Critical patent/EP4113686A4/en
Priority to KR1020227027730A priority patent/KR20220123718A/ko
Priority to JP2022548242A priority patent/JP7454059B2/ja
Publication of WO2022161270A1 publication Critical patent/WO2022161270A1/zh
Priority to US18/086,217 priority patent/US20230128934A1/en

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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
    • H01M10/056—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
    • 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
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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
    • H01M2300/0034—Fluorinated solvents
    • 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
    • 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

Definitions

  • the present application relates to lithium ion batteries, and in particular, to a lithium ion battery with high energy density and low gas production, a preparation method thereof, a battery module, a battery pack and an electrical device.
  • lithium-ion batteries are widely used in various large-scale power devices, energy storage systems and various consumer products due to their excellent electrochemical performance, no memory effect, and low environmental pollution. It is widely used in the field of new energy vehicles such as pure electric vehicles and hybrid electric vehicles.
  • lithium-ion batteries In the field of new energy vehicles, consumers have put forward higher requirements for the battery life of lithium-ion batteries.
  • the current lithium-ion batteries are difficult to meet people's higher demand for battery life, so the development of lithium-ion batteries with higher energy density has become one of the main directions of lithium-ion battery research and development.
  • the present application has been made in view of the above-mentioned problems, and an object of the present application is to provide a lithium ion battery, a battery module, a battery pack, and an electrical device with high energy density and low gas production.
  • the lithium ion battery of the present application can not only improve the energy density of the lithium ion battery, but also can significantly reduce the amount of chemical gas production and the phenomenon of black spot lithium deposition, which is beneficial to improve the electrochemical performance and safety performance of the lithium ion battery.
  • An object of the present application is to provide a lithium-ion battery with high energy density.
  • An object of the present application is to provide a high-energy-density lithium-ion battery with a low gas yield.
  • An object of the present application is to provide a lithium ion battery with significantly improved negative black spot and lithium deposition phenomena.
  • An object of the present application is to provide a lithium-ion battery with low battery internal resistance and high energy density.
  • An object of the present application is to provide a high energy density lithium ion battery with improved cycle performance.
  • the application provides a lithium-ion battery, including:
  • an electrode assembly comprising a negative electrode current collector and a negative electrode material disposed on at least one surface of the negative electrode current collector;
  • Electrolytes containing fluorosulfonates and/or difluorophosphates
  • the M is the loading amount of the negative electrode material on the negative electrode current collector per unit area, and the unit is mg/cm 2 , and the range of the M is 5 mg/cm 2 to 100 mg/cm 2 ,
  • the S is the specific surface area of the negative electrode material on the negative electrode current collector, and its unit is m 2 /g, and the range of the S is 0.1m 2 /g ⁇ 10m 2 /g ,
  • the L is the width of the coating region of the negative electrode material on the surface of the negative electrode current collector, and its unit is mm, and the range of the L is L ⁇ 50mm,
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte, the chemical formation gas area coefficient ⁇ of the lithium ion battery and the lithium ion battery satisfies the formula (III) of 0.01 ⁇ w ⁇ / ⁇ 20.
  • the inventors of the present application have found through extensive research and experiments that when the mass percentage w% of fluorosulfonates and/or difluorophosphates in the electrolyte, the area coefficient of chemical gas production is ⁇ , and the exhaust path coefficient is ⁇
  • the lithium-ion battery has improved energy density, and has a very low formation gas yield, which can effectively prevent black spots and lithium precipitation at the negative end during formation, which is beneficial to Improve the internal resistance of the battery and improve the electrical performance of the battery.
  • the present application starts with the structure of the lithium-ion battery itself, through the joint regulation of various structural parameters of the battery and the type and content of electrolyte additives, and the synergistic effect of various internal structural parameters and electrolyte parameters of the battery to obtain high energy density lithium ion At the same time, it solves the problems of serious gas production and black spots on the negative electrode during the formation of high-energy density lithium-ion batteries, and significantly improves the internal resistance and electrical properties of lithium-ion batteries.
  • the structural formula of the fluorosulfonate is (FSO 3 ) y My+ , and My+ is selected from Li + , Na + , K + , Rb + , Cs + , Mg 2+ , One of Ca 2+ , Ba 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ and Ni 3+ .
  • the structural formula of the difluorophosphate is (F 2 PO 2 ) y My+ , and My+ is selected from Li + , Na + , K + , Rb + , Cs + , Mg 2 One of + , Ca 2+ , Ba 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ and Ni 3+ .
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.01% to 11%, optionally It is 0.5% to 10%, and more preferably 0.5% to 5%.
  • adding an appropriate amount (0.01% to 11%) of fluorosulfonates and/or difluorophosphates to the electrolyte can significantly reduce the amount of chemical gas production.
  • adding an appropriate amount of fluorosulfonates and/or difluorophosphates within an appropriate range, on the one hand, black spots on the negative electrode can be avoided, and on the other hand, the increase in the viscosity of the electrolyte, which affects the conductivity of the electrolyte, can be avoided. Internal resistance increases.
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte may be 0.5-10%.
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte may be 0.5-5%.
  • the mass percentage w% of fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.5% to 10%, there is no black spot phenomenon at the negative end, and the lithium ion battery With significantly improved chemical gas production, battery volumetric energy density and battery internal resistance are also at an optimal level.
  • the mass percentage w% of fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.5% to 5%, the corresponding lithium ion battery also has excellent performance. High temperature cycle characteristics and normal temperature cycle characteristics.
  • the range of the loading amount M of the negative electrode material on the negative electrode current collector per unit area is 11 mg/cm 2 -80 mg/cm 2 , optionally 11 mg/cm 2 -50 mg/cm 2 .
  • the loading amount M of the negative electrode material on the negative electrode current collector per unit area is small (M is lower than 11 mg/cm 2 ), the volume energy density of the lithium ion battery is adversely affected.
  • the loading amount is within an appropriate range, the increase of the contact area between the negative electrode material and the electrolyte can be avoided, thereby preventing the increase of chemical gas production and the increase of the internal resistance of the battery.
  • the specific surface area S of the negative electrode material on the negative electrode current collector ranges from 0.5 m 2 /g to 5 m 2 /g.
  • the reaction kinetics at the interface between the electrolyte and the negative electrode material can be improved, thereby reducing the interface reaction resistance and improving the energy density of the battery. On the other hand, it can reduce the gas production and avoid black spots at the negative end.
  • the width L of the coating region of the negative electrode material on the surface of the negative electrode current collector is in the range of 50 mm ⁇ L ⁇ 200 mm, optionally 50 mm ⁇ L ⁇ 100 mm.
  • the width L of the coating area of the negative electrode material is within an appropriate range, on the one hand, the diffusion path of the gas generated by the chemical formation can be prevented from becoming longer, so that the gas discharge speed is not affected, and the occurrence of black spots and the internal resistance of the battery are avoided. impact; on the other hand, the impact on the energy density of lithium-ion batteries can be reduced.
  • the electrolyte contains fluoroethylene carbonate and/or 1,3-propane sultone.
  • the porosity of the negative electrode material is 10% to 40%.
  • the greater the porosity of the negative electrode material the more and more smooth the paths for the gas generated by chemical formation to diffuse from the inside of the negative electrode material to the interface between the negative electrode and the separator.
  • the porosity of the negative electrode material exceeds 50%, the volumetric energy density of the lithium-ion battery decreases.
  • the porosity of the negative electrode material is lower than 10%, the intercalation/extraction resistance of lithium ions of the negative electrode material is relatively large, thereby having a certain influence on the internal resistance of the battery.
  • the porosity of the negative electrode material By limiting the porosity of the negative electrode material to 10% to 40%, the gas generated inside the negative electrode material can be quickly diffused, and at the same time, the battery can have high volume energy density and low battery internal resistance.
  • a second aspect of the present application provides a battery module including the lithium-ion battery of the first aspect of the present application.
  • a third aspect of the present application provides a battery pack, including the lithium ion battery of the first aspect of the present application or the battery module of the second aspect of the present application.
  • a fourth aspect of the present application provides an electrical device, comprising at least one of the lithium ion battery of the first aspect of the present application, the battery module of the second aspect of the present application, or the battery pack of the third aspect of the present application.
  • FIG. 1 is a schematic diagram of a lithium-ion lithium-ion battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the lithium ion battery according to the embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to the embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device according to an embodiment of the present application.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with any other lower limit to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range.
  • each individually disclosed point or single value may itself serve as a lower or upper limit in combination with any other point or single value or with other lower or upper limits to form a range that is not expressly recited.
  • the common solution is to reduce the chemical gas production rate by reducing the chemical current, and accelerate the gas extraction speed by pumping negative pressure to ensure that the gas inside the battery is discharged in time.
  • this conventional method cannot discharge the formation gas in time, thereby deteriorating the formation interface.
  • Another way to reduce gas production is to use a small-current staged pressurization method, but this method is cumbersome, time-consuming, and has poor operational stability, which is not conducive to large-scale industrial applications.
  • the lithium-ion battery satisfying this relational expression not only has a significantly improved high energy density, but also can reduce the amount of chemical gas produced.
  • the theoretical relationship proposed in this application is not limited to being applicable to one battery structure.
  • the shape of the battery is changed, the winding method of the bare cell is changed, or the stacking method of the bare cell is changed due to other requirements, the theoretical relationship is also the same. Be applicable.
  • a lithium-ion battery typically includes a positive pole piece, a negative pole piece, an electrolyte and a separator.
  • active ions are inserted and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the separator is arranged between the positive pole piece and the negative pole piece, and mainly plays the role of preventing the short circuit of the positive and negative poles, and at the same time, it can allow ions to pass through.
  • the application provides a lithium-ion battery, including:
  • an electrode assembly comprising a negative electrode current collector and a negative electrode material disposed on at least one surface of the negative electrode current collector;
  • Electrolytes containing fluorosulfonates and/or difluorophosphates
  • the M is the loading amount of the negative electrode material on the negative electrode current collector per unit area, and the unit is mg/cm 2 , and the range of the M is 5 mg/cm 2 to 100 mg/cm 2 ,
  • the S is the specific surface area of the negative electrode material on the negative electrode current collector, and its unit is m 2 /g, and the range of the S is 0.1m 2 /g ⁇ 10m 2 /g ,
  • the L is the width of the coating region of the negative electrode material on the surface of the negative electrode current collector, and its unit is mm, and the range of the L is L ⁇ 50mm,
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte, the chemical formation gas area coefficient ⁇ of the lithium ion battery and the lithium ion battery satisfies the formula (III) of 0.01 ⁇ w ⁇ / ⁇ 20.
  • the gas produced by chemical formation is mainly generated in the process of the reduction and decomposition of organic components in the electrolyte, such as organic solvents or organic additives, on the surface of the negative electrode material to form an interface protective film during the chemical formation process.
  • organic components in the electrolyte such as organic solvents or organic additives
  • Increasing the load M of the negative electrode material on the current collector per unit area can significantly improve the volumetric energy density of the battery on the one hand, but on the other hand, it will also increase the contact area between the negative electrode material and the electrolyte, thereby causing more electrolyte to reduce and decompose. more gas is produced.
  • choosing a negative electrode material with a larger specific surface area S can increase the contact area between the negative electrode material and the electrolyte, reduce the transport resistance of lithium ions at the phase interface, and then improve the energy density of the battery.
  • the increase in the contact area of the ions will also cause more electrolyte to reduce and decompose, thereby generating more gas.
  • the specific surface area S of the negative electrode material and the loading amount M of the negative electrode material on the current collector per unit area affect the chemical formation gas production by affecting the contact area between the electrolyte and the negative electrode material.
  • the present application defines the exhaust path coefficient ⁇ related to L, and the size of ⁇ can indicate the difficulty of the gas produced by chemical conversion.
  • the common electrolytes of lithium-ion batteries often include organic solvents and organic additives. During the formation process, these organic components are preferentially reduced on the surface of the negative electrode to form a protective film on the negative electrode interface, and at the same time, gaseous products are generated. Based on this, the present application replaces some conventional organic additives with fluorosulfonate or difluorophosphate inorganic additives by improving the formulation of the electrolyte.
  • inorganic additives can be reduced on the surface of the negative electrode in preference to organic solvents, and can be directly added to the negative electrode such as graphite.
  • the surface of the active material is reduced to form an inorganic coating layer, so no gas product will be formed, and there will be no problem of gas production from the decomposition of additives.
  • the inorganic coating layer has been preferentially reduced on the surface of the negative electrode active material, the reduction and decomposition of the electrolyte solvent on the negative electrode surface can be effectively suppressed, thereby further reducing the amount of gas produced by the reduction and decomposition of the electrolyte solvent.
  • the range of M is 5 mg/cm 2 -100 mg/cm 2
  • the range of S is 0.1 m 2 /g - 10 m 2 /g
  • the range of L is L ⁇ 50mm
  • the obtained lithium-ion battery has a significantly improved energy density, and has a very low chemical formation gas yield, which can effectively prevent black spots and lithium precipitation at the negative end during chemical formation, and is conducive to improving the internal battery. resistance and improve the electrical performance of the battery.
  • the value of w ⁇ / ⁇ may be 19.14, 3.83, 0.64, 0.38, 0.19, 1.74, 0.96, 0.24, 0.83, 1.10, 1.65, 3.31, 0.02, 0.87, 1.74, 3.48, 8.70, 17.40, 19.14 , or its value is within the range obtained by combining any two of the above-mentioned values.
  • This application starts with the structure of the lithium-ion battery itself, and develops and designs a high-efficiency battery by jointly regulating various structural parameters of the electrode components and the types and contents of electrolyte additives, and synthesizing the synergistic effect of various structural parameters and electrolyte parameters inside the battery.
  • the lithium-ion battery with high energy density also solves the problems of serious gas production and black speckle of lithium in the negative electrode during the formation of high-energy density lithium-ion battery, and significantly improves the internal resistance and electrical performance of the lithium-ion battery.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the electrolyte described in this application contains fluorosulfonates and/or difluorophosphates.
  • the structural formula of the fluorosulfonate is (FSO 3 ) y My+ , and My+ is selected from Li + , Na + , K + , Rb + , Cs + , Mg 2+ , One of Ca 2+ , Ba 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ and Ni 3+ .
  • the structural formula of the difluorophosphate is (F 2 PO 2 ) y My+ , and My+ is selected from Li + , Na + , K + , Rb + , Cs + , Mg 2 One of + , Ca 2+ , Ba 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ and Ni 3+ .
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.01% to 11%, optionally It is 0.5% to 10%, and more preferably 0.5% to 5%.
  • adding an appropriate amount (0.01% to 11%) of fluorosulfonates and/or difluorophosphates to the electrolyte can significantly reduce the amount of chemical gas production.
  • the amount of fluorosulfonate and/or difluorophosphate added in an appropriate range on the one hand, black spots and lithium precipitation at the negative end can be avoided, and on the other hand, the viscosity of the electrolyte can be prevented from increasing and the electrolyte can be deteriorated. To a certain extent, it can avoid the increase of the internal resistance of the battery due to the decrease of the migration rate of the electrolyte.
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte may be 0.5-10%.
  • the mass percentage w% of the fluorosulfonates and/or difluorophosphates in the electrolyte may be 0.5-5%.
  • the mass percentage w% of fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.5% to 10%, there is no black spot phenomenon at the negative end, and the lithium ion battery With significantly improved chemical gas production, battery volumetric energy density and battery internal resistance are also at an optimal level.
  • the mass percentage w% of fluorosulfonates and/or difluorophosphates in the electrolyte is in the range of 0.5% to 5%, the corresponding lithium ion battery also has excellent performance. High and low temperature cycle performance.
  • the value of w% may be 0.01%, 0.1%, 0.5%, 1%, 2%, 5%, 10%, 11%, or within a range obtained by combining any two of the above-mentioned values.
  • the solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate ester (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB) , one or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl s
  • EC
  • the fluorosulfonate and/or difluorophosphate-containing electrolyte also optionally includes additives.
  • the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performance of the battery, such as additives to improve battery overcharge performance, additives to improve battery high temperature performance, and battery low temperature performance.
  • the additives, etc. can be fluoroethylene carbonate (FEC), 1,3-propane sultone (PS) and the like.
  • the electrolyte further optionally includes a lithium salt
  • the lithium salt may be selected from LiN(C x F 2x +1SO 2 )(C y F 2y +1SO 2 ), LiPF 6 , LiBF 4.
  • LiBOB LiAsF 6 , Li(FSO 2 ) 2 N, LiCF 3 SO 3 and LiClO 4 , wherein x and y are natural numbers.
  • the negative electrode sheet may include a negative electrode current collector and a negative electrode material disposed on at least one surface of the negative electrode current collector.
  • the negative electrode material includes a negative electrode active material, and examples of the negative electrode active material include artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.
  • the silicon-based material can be selected from one or more of elemental silicon, silicon-oxygen compound, silicon-carbon composite, silicon-nitrogen composite and silicon alloy.
  • the tin-based material can be selected from one or more of elemental tin, tin oxide compounds and tin alloys.
  • the loading amount M of the negative electrode material on the negative electrode current collector per unit area ranges from 11 mg/cm 2 to 80 mg/cm 2 , optionally from 11 mg/cm 2 to 50 mg/cm 2 .
  • the loading amount M of the negative electrode material on the negative electrode current collector per unit area is changed by means known to those skilled in the art, for example, by changing the coating times of the slurry coating process.
  • the specific surface area S of the negative electrode material on the negative electrode current collector per unit area ranges from 0.5 m 2 /g to 5 m 2 /g.
  • the present application changes the specific surface area S in a manner known to those skilled in the art, for example, by adding different contents of artificial graphite with different specific surface areas S into the slurry.
  • the reaction kinetics at the interface between the electrolyte and the negative electrode material can be improved, thereby reducing the internal resistance of the battery; spot.
  • the value of S can be 0.1, 0.5, 1.1, 3, 5, 10, or its value is within the range obtained by combining any two of the above-mentioned values.
  • the negative electrode current collector has two surfaces opposite in its own thickness direction, and the negative electrode material is provided on either or both of the two opposite surfaces of the negative electrode current collector.
  • the width L of the coating region of the negative electrode material on the surface of the negative electrode current collector is in the range of 50 mm ⁇ L ⁇ 200 mm, optionally 50 mm ⁇ L ⁇ 100 mm.
  • the width L of the coating region of the negative electrode material is changed by means known to those skilled in the art, for example, by changing the cutting process.
  • the width L of the coating area of the negative electrode material is within an appropriate range, on the one hand, the diffusion path of the gas generated by chemical formation can be prevented from becoming longer, so that the gas discharge speed will not be affected, and the occurrence of black spots and the internal resistance of the battery will not be affected. ; On the other hand, it can reduce the impact on the energy density of lithium-ion batteries.
  • the value of L can be 200, 150, 100, 95, 50, or its value is within the range obtained by combining any two of the above-mentioned values.
  • the porosity of the negative electrode material is 10% to 40%.
  • the porosity of the negative electrode material the more and more smooth the paths for the gas generated by chemical formation to diffuse from the inside of the negative electrode material to the interface between the negative electrode and the separator.
  • the porosity of the negative electrode material exceeds 50%, the volumetric energy density of lithium-ion batteries tends to decrease.
  • the porosity of the negative electrode material is lower than 10%, the intercalation/extraction resistance of lithium ions of the negative electrode material is relatively large, so that the internal resistance of the battery tends to increase.
  • the porosity of the negative electrode material By limiting the porosity of the negative electrode material to 10% to 40%, the gas generated inside the negative electrode material can be quickly diffused, and at the same time, the battery can have high volume energy density and low battery internal resistance.
  • the porosity of the negative electrode material may be 10%, 15%, 35%, or within a range obtained by combining any two of the above-mentioned values.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil can be used.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid ethylene glycol ester (PET), polybutylene terephthalate (PBT), 1,3-propane sultone (PS), polyethylene (PE) and other substrates).
  • PP polypropylene
  • PET polyethylene terephthalic acid ethylene glycol ester
  • PBT polybutylene terephthalate
  • PS 1,3-propane sultone
  • PE polyethylene
  • the negative electrode material usually includes a negative electrode active material and an optional binder, an optional conductive agent and other optional auxiliary agents, and is usually formed by coating and drying the negative electrode slurry.
  • the negative electrode slurry coating is usually formed by dispersing the negative electrode active material and optional conductive agent and binder in a solvent and stirring uniformly.
  • the solvent can be N-methylpyrrolidone (NMP) or deionized water.
  • the conductive agent may be selected from one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the binder may be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), One or more of polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • PAAS sodium polyacrylate
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • PMAA polymethacrylic acid
  • CMCS carboxymethyl chitosan
  • CMC-Na sodium carboxymethyl cellulose
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode material disposed on at least one surface of the positive electrode current collector.
  • the positive electrode current collector has two surfaces opposite in its own thickness direction, and the positive electrode material is disposed on either or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.
  • Composite current collectors can be formed by metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) ethylene glycol ester (PET), polybutylene terephthalate (PBT), 1,3-propane sultone (PS), polyethylene (PE) and other substrates), but this The application is not limited to these materials.
  • the positive electrode material includes a positive electrode active material, and the positive electrode active material is selected from materials capable of extracting and intercalating lithium ions.
  • the positive electrode active material can be selected from lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel oxide Cobalt aluminum oxide and one or more compounds obtained by adding other transition metals or non-transition metals to the above compounds, but the present application is not limited to these materials.
  • the positive electrode material also optionally includes a conductive agent.
  • a conductive agent is not specifically limited, and those skilled in the art can select them according to actual needs.
  • the conductive agent for the positive electrode material may be selected from one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared according to methods known in the art.
  • the cathode material, conductive agent and binder of the present application can be dispersed in a solvent such as N-methylpyrrolidone (NMP) to form a uniform cathode slurry; the cathode slurry can be coated on the cathode current collector , after drying, cold pressing and other processes, the positive pole piece is obtained.
  • NMP N-methylpyrrolidone
  • Separators are also included in lithium-ion batteries using electrolytes, and some lithium-ion batteries using solid-state electrolytes.
  • the separator is arranged between the positive pole piece and the negative pole piece, and plays the role of isolation.
  • the type of separator in the present application, and any well-known porous-structure separator with good chemical stability and mechanical stability can be selected.
  • the material of the separator can be selected from one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator may be a single-layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, and are not particularly limited.
  • the positive electrode sheet, the negative electrode sheet and the separator may be fabricated into an electrode assembly through a winding process or a lamination process.
  • the lithium-ion battery can include an outer packaging.
  • the outer package can be used to encapsulate the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the lithium-ion battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, and the like.
  • the outer package of the lithium-ion battery can also be a soft package, such as a bag-type soft package.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), and the like.
  • FIG. 1 is a lithium ion battery 5 of a square structure as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate are enclosed to form a accommodating cavity.
  • the housing 51 has an opening that communicates with the accommodating cavity, and a cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating cavity.
  • the electrolyte solution is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the lithium ion battery 5 may be one or more, and those skilled in the art may select them according to specific actual needs.
  • the lithium ion batteries can be assembled into a battery module, and the number of lithium ion batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of lithium ion batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of lithium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodating space, and the plurality of lithium ion batteries 5 are accommodated in the accommodating space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules included in the battery pack can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case.
  • the battery box includes an upper box body 2 and a lower box body 3 .
  • the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • the plurality of battery modules 4 may be arranged in the battery case in any manner.
  • the present application also provides an electrical device, where the electrical device includes one or more of the lithium-ion batteries, battery modules, or battery packs provided in the present application.
  • the lithium-ion battery, battery module, or battery pack can be used as a power source for the device, or as an energy storage unit for the device.
  • the device may be, but is not limited to, mobile devices (eg, cell phones, laptops, etc.), electric vehicles (eg, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf balls) vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • a lithium-ion battery, a battery module or a battery pack can be selected according to its usage requirements.
  • Figure 6 is an apparatus as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like.
  • battery packs or battery modules can be employed.
  • the device may be a mobile phone, a tablet computer, a laptop computer, and the like.
  • the device is usually required to be thin and light, and a lithium-ion battery can be used as a power source.
  • the positive active material LiNi 0.8 Mn 0.1 Co 0.1 O 2 , the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) were dissolved in the solvent N-methylpyrrolidone (NMP) in a weight ratio of 94:3:3 , fully stirred and mixed to obtain a positive electrode slurry; then the positive electrode slurry is uniformly coated on the positive electrode current collector, and then dried, cold pressed, and cut to obtain a positive electrode pole piece.
  • NMP N-methylpyrrolidone
  • the organic solvent EC/EMC was mixed uniformly according to the volume ratio of 3/7, 12.5% LiPF6 lithium salt was added to dissolve in the organic solvent, and then Lithium fluorosulfonate accounting for 1% of the total mass of the electrolyte solution was added and stirred evenly to obtain the electrolyte solution of Example 1.
  • a polypropylene film was used as the separator.
  • Examples 2 to 24 and Examples 27 to 37 respectively corresponding to the specific surface area S of the negative electrode material, the loading amount M of the negative electrode material on the negative electrode current collector, the width L of the coating area of the negative electrode material, the fluorosulfonate in the electrolyte
  • the content w% of /difluorophosphate is shown in Table 1, and other process conditions are the same as those in Example 1.
  • the lithium ion battery products of Examples 2-24 and Examples 27-37 were obtained respectively.
  • Example 20 Except for adding 1% fluoroethylene carbonate (FEC) to the electrolyte, other parameters and process are the same as in Example 20, and the lithium ion battery product of Example 25 is obtained.
  • FEC fluoroethylene carbonate
  • Example 20 Except that 1,3-propane sultone (PS), which accounts for 1% of the mass of the electrolyte, is additionally added to the electrolyte, other parameters and processes are the same as in Example 20, and the lithium ion battery product of Example 26 is obtained.
  • PS 1,3-propane sultone
  • Comparative Examples 1 to 7 the corresponding specific surface area S of the negative electrode material, the loading amount M of the negative electrode material on the negative electrode current collector, the width L of the coating area of the negative electrode material, and the fluorosulfonate/difluorophosphate in the electrolyte.
  • the content w% is shown in Table 1, and other process conditions are the same as those in Example 1.
  • the lithium-ion battery products of Comparative Examples 1 to 7 were obtained respectively.
  • the negative electrode materials on the negative electrode plates of all the examples and comparative examples were scraped off with a blade, and then tested with reference to the standard GB/T 21650.2-2008. Refer to Table 1 for specific values.
  • a vernier caliper was used to measure the length L of the negative electrode material-coated area on the negative pole pieces of all the examples and comparative examples, respectively. Refer to Table 1 for specific values.
  • the lithium-ion battery was charged to 4.2V at a constant current of 1C, then charged at a constant voltage of 4.2V until the current was less than 0.05C, and then discharged to 2.8V at 0.33C to obtain the discharge energy Q.
  • Use a vernier caliper to measure the length, width and height of the battery, and calculate the volume V, then the volume energy density Q/V.
  • the lithium-ion battery was charged to 4.2V at a constant current of 1C, then charged at a constant voltage of 4.2V until the current was less than 0.05C, and then discharged at 0.5C for 60 minutes, that is, the power of the cell was adjusted to 50% SOC. Then use an AC internal resistance tester to connect the positive and negative poles of the cell to test the internal resistance of the battery.
  • the perturbation is 5mV and the frequency is 1000 Hz.
  • the capacity retention rate (%) of the lithium ion battery after 25 cycles of 1000 cycles (discharge capacity of the 1000th cycle/discharge capacity of the first cycle) ⁇ 100%.
  • the capacity retention rate (%) of the lithium ion battery after 25 cycles of 1000 times (discharge capacity at the 800th cycle/discharge capacity at the first cycle) ⁇ 100%.
  • Table 1 Table of relevant parameters of lithium-ion batteries of examples and comparative examples
  • Table 2 Relevant parameters and performance test table of lithium-ion batteries of examples and comparative examples
  • Example 1 0.055 1.05 19.14 No black spots, no lithium precipitation 575 0.388 Example 2 0.275 1.05 3.83 No black spots, no lithium precipitation 570 0.366 Example 3 1.65 1.05 0.64 No black spots, no lithium precipitation 569 0.349 Example 4 2.75 1.05 0.38 No black spots, no lithium precipitation 562 0.342 Example 5 5.5 1.05 0.19 few dark spots 550 0.335 Example 6 0.275 1.05 3.83 No black spots, no lithium precipitation 550 0.214
  • Example 7 0.605 1.05 1.74 No black spots, no lithium precipitation 570 0.356
  • Example 8 1.1 1.05 0.96 No black spots, no lithium precipitation 575 0.361
  • Example 9 2.75 1.05 0.38 No black spots, no lithium precipitation 578 0.374
  • Example 10 4.4 1.05 0.24 few dark spots 579 0.396
  • Example 11 5.5 1.05 0.19 few dark spots 576 0.411
  • Example 12 0.605 0.50 0.
  • Example 15 0.605 1.05 1.74 No black spots, no lithium precipitation 570 0.356
  • Example 16 0.605 2.00 3.31 No black spots, no lithium precipitation 565 0.352
  • Example 17 0.605 1.05 0.02 more dark spots 565 0.375
  • Example 18 0.605 1.05 0.17 few dark spots 568 0.359
  • Example 19 0.605 1.05 0.87 No black spots, no lithium precipitation 571 0.351
  • Example 20 0.605 1.05 1.74 No black spots, no lithium precipitation 570 0.356
  • Example 21 0.605 1.05 3.48 No black spots, no lithium precipitation 571 0.359
  • Example 22 0.605 1.05 8.70 No black spots, no lithium precipitation 572 0.365
  • Example 23 0.605 1.05 17.40 No black spots, no lithium precipitation 575 0.369
  • Example 24 0.605 1.05 19.14 No black spots, no lithium precipitation 569 0.375
  • Example 25 0.605 1.05 1.74 No black spots, no lithium precipitation 570 0.341
  • Example 26
  • Table 3 Relevant parameters and performance test table of lithium ion batteries of examples and comparative examples
  • Table 4 Relevant parameters and performance test table of lithium-ion batteries of examples and comparative examples
  • the designed and developed lithium ion batteries satisfy the relational expression 0.01 ⁇ w ⁇ / ⁇ 20, corresponding to Lithium ion has both the following advantages: maintaining high energy density (the volumetric energy density of lithium ion batteries in Examples 1 to 37 is above 550WhL -1 ), and the problem of gas production from chemical formation is significantly improved (lithium ion batteries in Examples 1 to 37 did not There are a lot of black spots and lithium deposition), and the internal resistance of lithium-ion batteries is relatively low (the internal resistances of lithium-ion batteries in Examples 1 to 37 are all below 0.46 m ⁇ , and most of them are located at 0.30 to 0.37 m ⁇ ).
  • the lithium-ion battery of Comparative Example 3 does not have black spots, its volumetric energy density is very low (only 530WhL -1 ).
  • the lithium-ion battery of Comparative Example 4 has a large number of black spots, and the internal resistance of the battery is very high (0.553m ⁇ ).
  • the lithium-ion battery of Comparative Example 5 does not have black spots, its internal resistance is very high (0.658m ⁇ ).
  • the lithium-ion batteries of Comparative Example 6 and Comparative Example 7 do not have black spots, their volumetric energy densities are very low (only 500 WhL -1 and 350 WhL -1 , respectively).
  • the lithium ion battery has high energy density, no dark spots, significantly improved chemical gas production, and battery internal resistance. Low. Further, in Examples 19 to 22, when the w% is in the range of 0.5% to 5%, the corresponding lithium ion batteries also have excellent high temperature cycle performance and low temperature cycle performance.
  • M is in the range of 11 mg/cm 2 to 80 mg/cm 2 , and the battery energy density is at a relatively high level (570 to 579 WhL -1 ), the internal resistance of the battery is also below 0.4m ⁇ .
  • the amount of M was lower (5 mg/cm 2 ), and the energy density of the lithium-ion battery was lower (550 WhL ⁇ 1 ); for Example 11, the amount of M was higher (100 mg/cm 2 ), The energy density of lithium-ion batteries is low (550WhL -1 ), and the internal resistance of lithium-ion batteries is correspondingly large (0.411m ⁇ ).
  • the value of M is in the range of 11mg/cm 2 to 50mg/cm 2 , there is no black spot phenomenon in the lithium-ion battery, the problem of chemical formation and gas generation is significantly improved, and the battery energy density and battery internal resistance are maintained at a high level. also lower.
  • the S of Examples 2 to 4 is in the range of 0.5 m 2 /g to 5 m 2 /g, the energy density of the lithium ion battery is relatively high, and the negative terminal does not appear black. spots, and the problem of chemical gas production has been significantly improved.
  • the value of S is small (0.1 m 2 /g), resulting in a large internal resistance of the battery; for Example 5, the value of S (10 m 2 /g) is large, which makes the negative electrode material and the electrolyte The contact area of is increased, so that black spots appear at the negative end.
  • the L of Examples 12 to 16 is within the range of 50mm ⁇ L ⁇ 200mm. High energy density levels with low internal resistance of the battery.
  • L is in the range of 50mm ⁇ L ⁇ 100mm.
  • the lithium-ion battery not only has a high energy density level and a low battery internal resistance, but also has no black spots at the negative end, which turns into gas. The problem has been significantly improved.
  • the porosity of Examples 33, 35 and 36 is in the range of 10% to 40%, so the corresponding lithium ion battery internal resistance (below 0.41m ⁇ ) and volumetric energy density are relatively high. High ( ⁇ 570WhL -1 ) was maintained at a good level.
  • the porosity of the negative electrode material of Example 34 is relatively low, and the internal resistance of the battery is relatively large, and the negative electrode material of Example 37 is relatively high in porosity, and the volumetric energy density of the lithium ion battery is relatively low.
  • this application is not limited to the said embodiment.
  • the above-described embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and exhibiting the same effects within the scope of the technical solution of the present application are all included in the technical scope of the present application.
  • various modifications that can be conceived by those skilled in the art are applied to the embodiment, and other forms constructed by combining some of the constituent elements of the embodiment are also included in the scope of the present application. .

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Abstract

本申请提供一种锂离子电池，包括电极组件和包含氟磺酸盐类和/或二氟磷酸盐类物质的电解液。设锂离子电池的化成产气面积系数为α，α＝M×S/200，M为单位面积负极集流体上的负极材料的负载量，M的范围为5mg/cm 2～100mg/cm 2，S为所述负极集流体上的负极材料的比表面积，S的范围为0.1m 2/g～10m 2/g；设锂离子电池的排气路径系数为β，β＝100/L，L为负极集流体表面上的负极材料的涂覆区域的宽度，L的范围为L≥50mm；氟磺酸盐类和/或二氟磷酸盐类物质在电解液中的质量百分含量w％与α和β满足0.01≤w×β/α≤20。本申请的锂离子电池，能够兼顾高能量密度和低化成产气。

Description

锂离子电池、电池模块、电池包、及用电装置 技术领域
本申请涉及锂离子电池，尤其涉及一种高能量密度低产气量的锂离子电池及其制备方法、电池模块、电池包和用电装置。
背景技术
随着新能源领域的快速发展，锂离子电池凭借其优良的电化学性能、无记忆效应、环境污染小等优势广泛应用于各类大型动力装置、储能系统以及各类消费类产品中，尤其广泛应用于纯电动汽车、混合电动汽车等新能源汽车领域。
在新能源汽车领域，消费者对锂离子电池的续航能力提出了更高的要求。但目前的锂离子电池难以满足人们对续航能力的更高需求，因此更高能量密度的锂离子电池的开发成为锂离子电池研发的主要方向之一。
但是，高能量密度的电池在化成过程中，在负极形成稳定SEI膜的同时，电解液中的溶剂和部分添加剂会被还原或分解而使电池内部产气严重，而且，相比于低能量密度的电池，高能量密度的电池内部产气更为严重。如果化成产生的气体，例如甲烷、乙烷、乙烯、一氧化碳等，不能及时排出，则会在正负极间形成气泡，影响锂离子在正负极的嵌入和脱出，从而导致电池内阻增加、负极界面黑斑、负极界面局部析锂、容量发挥异常等问题，最终影响电池的电性能和安全性能。
因此，亟待开发出一种高能量密度且低化成产气量的锂离子电池。
发明内容
本申请是鉴于上述课题而进行的，目的在于提供一种能量密度高且产气量低的锂离子电池，电池模块、电池包以及用电装置。本申请的锂离子电池，不仅能够提高锂离子电池的能量密度，还能够显著降低化成产气量和黑斑析锂现象，有利于提高锂离子电池的电化学性能和安全性能。
本申请的一个目的在于，提供一种具有高能量密度的锂离子电池。
本申请的一个目的在于，提供一种低化成产气量的高能量密度的锂离子电池。
本申请的一个目的在于，提供一种显著改善的负极黑斑和析锂现象的锂离子电池。
本申请的一个目的在于，提供一种低电池内阻的高能量密度的锂离子电池。
本申请的一个目的在于，提供一种具有改善的循环性能的高能量密度的锂离子电池。
发明人发现，通过采用本申请的技术方案，能够实现一个或多个上述目的。
本申请提供一种锂离子电池，包括：
电极组件，所述电极组件包括负极集流体以及设置于所述负极集流体至少一个表面的负极材料；以及
电解液，包含氟磺酸盐类和/或二氟磷酸盐类物质，
设所述锂离子电池的化成产气面积系数为α，α＝M×S/200式(I)，
在所述式(I)中，所述M为单位面积所述负极集流体上的负极材料的负载量，其单位为mg/cm 2，所述M的范围为5mg/cm 2～100mg/cm 2，
在所述式(I)中，所述S为所述负极集流体上的负极材料的比表面积，其单位为m 2/g，所述S的范围为0.1m 2/g～10m 2/g，
设所述锂离子电池的排气路径系数为β，β＝100/L式(II)，
在所述式(II)中，所述L为所述负极集流体表面上的负极材料的涂覆区域的宽度，其单位为mm，所述L的范围为L≥50mm，
其中，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％、所述锂离子电池的化成产气面积系数α与所述锂离子电池的排气系数β满足0.01≤w×β/α≤20式(III)。
本申请发明人经过大量研究和实验发现，当电解液中氟磺酸盐类和/或二氟磷酸盐类的质量百分含量w％、化成产气面积系数为α以及排气路径系数为β满足关系式0.01≤w×β/α≤20时，锂离子电池具有改善的能量密度，并且具有很低的化成产气量，能够有效防止化成时负极端出现的黑斑和析锂现象，有利于改善电池内阻并提高电池的电性能。
本申请从锂离子电池本身的结构入手，通过联合调控电池的各种结构参 数以及电解液添加剂的种类和含量，综合电池内部各种结构参数和电解液参数的协同作用，得到高能量密度的锂离子电池，同时又解决了高能量密度锂离子电池化成过程产气严重、负极黑斑析锂的问题，显著改善了锂离子电池的内阻和电性能。
在任意实施方式中，可选地，所述氟磺酸盐的结构式为(FSO 3) yM y+，M y+选自Li +、Na +、K +、Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
在任意实施方式中，可选地，所述二氟磷酸盐的结构式为(F 2PO 2) yM y+，M y+选自Li +、Na +、K +、Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
在任意实施方式中，可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％的范围为0.01％～11％，可选为0.5％～10％，进一步可选为0.5％～5％。
在本申请的高能量密度锂离子电池的设计过程中，向电解液中加入适量(0.01％～11％)氟磺酸盐类和/或二氟磷酸盐类物质，能够显著降低化成产气量。通过设定氟磺酸盐类和/或二氟磷酸盐类物质的添加量在合适范围内，一方面避免负极端出现黑斑，一方面可以避免电解液粘度增加而影响电解液电导率导致电池内阻增加。
可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％可以为0.5～10％。
可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％可以为0.5～5％。
具体地，当氟磺酸盐类和/或二氟磷酸盐类物质在电解液中的质量百分含量w％在0.5％～10％的范围内时，负极端无黑斑现象，锂离子电池兼具显著改善的化成产气量，电池体积能量密度和电池内阻也处于较优水平。
进一步地，当氟磺酸盐类和/或二氟磷酸盐类物质在电解液中的质量百分含量w％在0.5％～5％的范围内时，相应的锂离子电池还兼具优良的高温循环特性和常温循环特性。
在任意实施方式中，可选地，所述单位面积负极集流体上的负极材料的负载量M的范围为11mg/cm 2～80mg/cm 2，可选为11mg/cm 2～50mg/cm 2。
当单位面积负极集流体上的负极材料的负载量M较少(M低于11mg/cm 2)，对锂离子电池的体积能量密度带来不利影响。当负载量为合适范围内时，能够避免负极材料与电解液的接触面积的增加，从而防止化成产气加剧以及电池内阻增加。
在任意实施方式中，可选地，所述负极集流体上的负极材料的比表面积S的范围为0.5m 2/g～5m 2/g。
当负极材料的比表面积S为合适范围内时，一方面能够提高电解液与负极材料的相界面处反应动力学，从而减小界面反应电阻，提高电池能量密度。另一方面能够减少化成产气量，避免负极端出现黑斑。
在任意实施方式中，可选地，所述负极集流体表面上的负极材料的涂覆区域的宽度L的范围为50mm≤L≤200mm，可选为50mm≤L≤100mm。
当负极材料的涂覆区域的宽度L为合适范围内时，一方面能够避免化成产生的气体的扩散路径变长，从而不影响气体排出速度，避免出现黑斑现象而对电池的内阻造成一定影响；另一方面，能够减少对锂离子电池的能量密度的影响。
在任意实施方式中，可选地，所述电解液中含有氟代碳酸乙烯和/或1,3-丙烷磺酸内酯。
经过大量实验和研究，当在含有氟磺酸盐和/或二氟磷酸盐的电解液中添加额外的氟代碳酸乙烯酯(FEC)和/或1,3-丙烷磺酸内酯(PS)时，在保证锂离子电池具有高能量密度和低化成产气量的前提下，能够显著提高锂离子电池的高低温循环性能。
在任意实施方式中，可选地，所述负极材料的孔隙率为10％～40％。
经过研究，负极材料的孔隙率越大，化成产生的气体从负极材料内部扩散到负极与隔离膜的界面的路径就越多越通畅。但是当负极材料的孔隙率超过50％时，锂离子电池的体积能量密度会降低。当负极材料的孔隙率低于10％时，负极材料的锂离子的嵌入/脱出阻力较大，从而对电池内阻造成一定影响。通过将负极材料的孔隙率限定为10％～40％，既可以使负极材料内部产生的气体快速扩散出来，同时也能确保电池具有较高的体积能量密度和较低的电池内阻。
本申请第二方面提供一种电池模块，包括本申请的第一方面的锂离子电 池。
本申请第三方面提供一种电池包，包括本申请第一方面的锂离子电池或本申请第二方面的电池模块。
本申请第四方面提供一种用电装置，包括本申请第一方面的锂离子电池、本申请第二方面的电池模块或本申请第三方面的电池包中的至少一种。
附图说明
图1是本申请一实施方式的锂离子锂离子电池的示意图。
图2是图1所示的本申请一实施方式的锂离子电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6是本申请一实施方式的用电装置的示意图。
附图标记说明：
1电池包
2上箱体
3下箱体
4电池模块
5锂离子电池
51壳体
52电极组件
53顶盖组件
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的高能量密度低产气量的锂离子电池、电池模块、电池包、用电装置。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
为了简明，本申请具体地公开了一些数值范围。然而，任意下限可以与任 意上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
常规锂离子电池降低化成产气的策略中，常用的解决方法是通过降低化成电流来降低化成产气生成速率，并通过抽负压加快气体抽出速度，以保证电池内部气体及时排出。但经过本申请发明人的深入研究，随着所设计电池能量密度的提高，特别是针对卷绕式电池，按照这种常规方法并不能及时排出化成气体，从而使化成界面劣化。
另一种降低产气的方式是采用小电流分段加压的化成方式，但是这种方式工序繁琐且耗时，操作稳定性差，不利于大规模工业化应用。
由此可见，若要改善锂离子电池化成产气的问题，仅通过调控电池化成过程中的某些工艺方法或操作步骤并不能满足实际需求。因此，若要找到一种长期且有效的改善锂离子电池产气问题的方式，最可行的方式是从锂离子电池本身的结构入手，通过联合调控电池的各种结构参数以及电解液添加剂的种类和含量，开发和设计出低化成产气的锂离子电池。
经过发明人的大量研究和实验，从开发和设计出高能量密度低化成产气量的角度出发，通过综合调控电极组件的结构参数和电解液的种类和含量，具体通过联合调控单位面积集流体上的活性材料的负载量、集流体上负载的活性材料的比表面积、活性材料的涂覆区域长度、以及向电解液中添加氟磺酸盐和/或二氟磷酸类物质，综合利用各种参数的协同作用关系，从锂离子电池本身的结构入手，开发和设计出低化成产气量的高能量密度的锂离子电池。
并且，经过发明人大量研究和实验，当氟磺酸盐和/或二氟磷酸类物质的含量与单位面积集流体上的活性材料的负载量、集流体上负载的活性材料的比表面积、活性材料的涂覆区域长度之间满足一定关系式时，具有满足该关系式的锂离子电池既具有显著提高的高能量密度又能够降低化成产气量。
本申请提出的理论关系式并不仅限于适用于一种电池结构，当因为其他需求改变电池的形状、改变裸电芯的卷绕方式或者改变裸电芯的叠片方式时，该理论关系式同样适用。
[锂离子电池]
通常情况下，锂离子电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
本申请提供一种锂离子电池，包括：
电极组件，所述电极组件包括负极集流体以及设置于所述负极集流体至少一个表面的负极材料；以及
电解液，包含氟磺酸盐类和/或二氟磷酸盐类物质，
设所述锂离子电池的化成产气面积系数为α，α＝M×S/200式(I)，
在所述式(I)中，所述M为单位面积所述负极集流体上的负极材料的负载量，其单位为mg/cm 2，所述M的范围为5mg/cm 2～100mg/cm 2，
在所述式(I)中，所述S为所述负极集流体上的负极材料的比表面积，其单位为m 2/g，所述S的范围为0.1m 2/g～10m 2/g，
设所述锂离子电池的排气路径系数为β，β＝100/L式(II)，
在所述式(II)中，所述L为所述负极集流体表面上的负极材料的涂覆区域的宽度，其单位为mm，所述L的范围为L≥50mm，
其中，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％、所述锂离子电池的化成产气面积系数α与所述锂离子电池的排气系数β满足0.01≤w×β/α≤20式(III)。
经过发明人大量研究和实验，若要设计和开发出高能量密度，同时又具有低化成产气量的锂离子电池，需要综合调控电池与提高电池高能量密度相关的、与降低化成产气相关的、既与提高电池高能量密度相关的又与降低化成产气相关的各种参数，而不是只单独调控某一个参数。
具体地，化成产气主要是化成过程中电解液中的有机成分，比如有机溶剂或有机添加剂在负极材料表面还原分解，形成界面保护膜的过程中产生的。增加单位面积集流体上负极材料的负载量M，一方面能够显著提高电池的体积能量密度，但另一方面也会相应增加负极材料与电解液的接触面积，进而造成更多电解液还原分解而产生更多气体。
同理，选用比表面积S较大的负极材料，一方面能够增加负极材料与电解液的接触面积，降低锂离子在相界面的传输阻力，进而提高电池的能量密度， 但是，负极材料与电解液的接触面积的增大也会使更多的电解液还原分解，进而产生更多气体。
由此看来，在保证所设计的锂离子电池具有高能量密度的前提下(M的范围为5mg/cm 2～100mg/cm 2、S的范围为0.1m 2/g～10m 2/g)，从化成过程中产生气体的角度出发，负极材料的比表面积S和单位面积集流体上负极材料的负载量M都通过影响电解液与负极材料的接触面积而影响化成产气，因此，本申请定义了与M和S相关的化成产气面积系数α，化成产气面积系数α能够从整体上表征电解液与负极材料的接触面积与化成产气的关系。经过发明人大量研究和实验，M、S和α满足关系式α＝M×S/200。
另一方面，从电池内部气体的排出角度考虑，在开发和设计本申请锂离子电池时，对于负极集流体表面上的负极材料的涂覆区域的宽度L，当L设计得较大时，有利于提高电池的体积能量密度，但另一方面也会相应增加电池内部气体的排出路径的长度。在实际裸电芯的设计中，为了进一步增加体积能量密度，需要将L设计得尽可能长，但过长的L并不利于化成产气的快速排出。
由此看来，在保证所设计的锂离子电池具有高能量密度的前提下(L的范围为L≥50mm)，从化成过程中及时排出气体的角度出发，负极材料的涂覆区域的宽度L通过影响气体扩散路径的长度来影响化成产气，因此，本申请定义了与L相关的排气路径系数β，β大小能够表示化成产生的气体排出的难易程度。经过发明人大量研究和实验，L和β满足关系式β＝100/L。
再一方面，从降低化成过程中气体的产生量的角度考虑，改善电解液的配方是更有效改善化成产气的方式。锂离子电池的常用电解液往往包括有机溶剂和有机添加剂，在化成过程中，这些有机成分优先在负极表面还原形成负极界面保护膜，并同时产生气体产物。基于此，本申请通过改善电解液的配方，以氟磺酸盐类或二氟磷酸盐类无机添加剂代替部分常规有机添加剂，这些无机添加剂能够优先于有机溶剂在负极表面还原，直接在石墨等负极活性物质表面还原形成无机物包覆层，因此不会有气体产物形成，也就不存在添加剂的分解产气问题。
进一步地，由于已经优先在负极活性物质表面还原形成无机物包覆层，因而能够有效抑制电解液溶剂在负极表面的还原分解，从而进一步减少了电解液溶剂的还原分解的产气量。
由此看来，在保证所设计的锂离子电池具有高能量密度的前提下(M的范围为5mg/cm 2～100mg/cm 2、S的范围为0.1m 2/g～10m 2/g、L的范围为L≥50mm)，从化成过程中产生气体的角度出发，在整个电池的设计和开发过程中，改善电解液的配方是从根本上降低气体生成量的方法。
但是，经过发明人大量的研究和实验，向电解液加入过多的无机盐类添加剂会增加电解液的粘度，恶化电解液电导率，并在一定程度上阻碍锂离子在电解液的迁移速率，进而导致电池内阻增加。
通过上述三方面的论述可知，开发和设计出高能量密度又兼具低化成产气的锂离子电池，是各种参数协同作用的结果，当与之相关的一个参数值改变时，与之相关的其他参数的值需要做出相对应的改变，才能保证电池体积能量密度和化成产气量同时维持在各自最优的范围。
在综合考虑与提高电池高能量密度相关的、与降低化成产气相关的、既与提高电池高能量密度相关的又与降低化成产气相关的各种参数的情况下，本申请发明人经过大量研究和实验发现，当电解液中氟磺酸盐类和/或二氟磷酸盐类的质量百分含量w％、化成产气面积系数为α以及排气路径系数为β满足关系式0.01≤w×β/α≤20时，得到的锂离子电池具有显著提高的能量密度，并且具有很低的化成产气量，能够有效防止化成中负极端出现的黑斑和析锂现象，有利于改善电池内阻并提高电池的电性能。
可选地，w×β/α的值可以为19.14、3.83、0.64、0.38、0.19、1.74、0.96、0.24、0.83、1.10、1.65、3.31、0.02、0.87、1.74、3.48、8.70、17.40、19.14，或者其数值在上述任意两个数值合并所获得的范围内。
本申请从锂离子电池本身的结构入手，通过联合调控电极组件的各种结构参数以及电解液添加剂的种类和含量，综合电池内部各种结构参数和电解液参数的协同作用，开发和设计出高能量密度的锂离子电池，同时又解决了高能量密度锂离子电池化成过程产气严重、负极黑斑析锂的问题，显著改善了锂离子电池的内阻和电性能。
[电解液]
电解液在正极极片和负极极片之间起到传导离子的作用。本申请中所述电解液包含氟磺酸盐类和/或二氟磷酸盐类物质。
在一些实施方式中，可选地，所述氟磺酸盐的结构式为(FSO 3) yM y+，M y+ 选自Li +、Na +、K +、Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
在一些实施方式中，可选地，所述二氟磷酸盐的结构式为(F 2PO 2) yM y+，M y+选自Li +、Na +、K +、Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
在一些实施方式中，可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％的范围为0.01％～11％，可选为0.5％～10％，进一步可选为0.5％～5％。
在本申请高能量密度锂离子电池的设计过程中，向电解液中加入适量(0.01％～11％)氟磺酸盐类和/或二氟磷酸盐类物质，能够显著降低化成产气量。通过氟磺酸盐类和/或二氟磷酸盐类物质的添加量在合适范围内，一方面避免负极端出现黑斑和析锂，另一方面又可以避免电解液的粘度增加而恶化电解液电导率，并在一定程度上避免锂离子因电解液的迁移速率的降低而导致电池内阻增加。
可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％可以为0.5～10％。
可选地，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％可以为0.5～5％。
具体地，当氟磺酸盐类和/或二氟磷酸盐类物质在电解液中的质量百分含量w％在0.5％～10％的范围内时，负极端无黑斑现象，锂离子电池兼具显著改善的化成产气量，电池体积能量密度和电池内阻也处于较优水平。
进一步地，当氟磺酸盐类和/或二氟磷酸盐类物质在电解液中的质量百分含量w％在0.5％～5％的范围内时，相应的锂离子电池还兼具优良的高低温循环性能。
可选地，w％的值可以为0.01％、0.1％、0.5％、1％、2％、5％、10％、11％，或者其数值在上述任意两个数值合并所获得的范围内。
在一些实施方式中，溶剂可选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙 酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种以上。
在一些实施方式中，所述含氟磺酸盐和/或二氟磷酸盐的电解液中还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、以及改善电池低温性能的添加剂等，例如，可以为氟代碳酸乙烯酯(FEC)、1,3-丙烷磺酸内酯(PS)等。
经过大量实验和研究，当在含有氟磺酸盐和/或二氟磷酸盐的电解液中添加额外的氟代碳酸乙烯酯(FEC)和/或1,3-丙烷磺酸内酯(PS)时，在保证锂离子电池具有高能量密度和低化成产气量的前提下，能够显著提高锂离子电池的高低温循环性能。
在一些实施方式中，所述电解液中还可选地包括锂盐，所述锂盐可选自LiN(C xF 2x+1SO 2)(C yF 2y+1SO 2)、LiPF 6、LiBF 4、LiBOB、LiAsF 6、Li(FSO 2) 2N、LiCF 3SO 3以及LiClO 4中的一种或几种，其中，x、y为自然数。
[负极极片]
负极极片可以包括负极集流体以及设置在负极集流体至少一个表面的负极材料。负极材料包含负极活性材料，作为负极活性材料可列举出人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的一种以上。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的一种以上。
在一些实施方式中，可选地，单位面积负极集流体上的负极材料的负载量M的范围为11mg/cm 2～80mg/cm 2，可选为11mg/cm 2～50mg/cm 2。
本申请通过本领域技术人员公知的方式改变单位面积负极集流体上的负极材料的负载量M，比如通过改变浆料涂布过程的涂敷次数。
当单位面积负极集流体上的负极材料的负载量M较少(M低于11mg/cm 2)，对锂离子电池的体积能量密度带来不利影响。当负载量从50mg/cm 2继续增大，一方面对电池体积能量密度的提升并不显著，另一方面，过多的负载量也会增加负极材料与电解液的接触面积，从而加剧化成产气，增加电池内阻。
在一些实施方式中，可选地，单位面积负极集流体上的负极材料的比表面 积S的范围为0.5m 2/g～5m 2/g。
本申请通过本领域技术人员公知的方式改变比表面积S，例如，通过向浆料中加入不同含量的具有不同比表面积S的人造石墨。
当负极材料的比表面积S在合适的范围内，一方面能够提高电解液与负极材料的相界面处反应动力学，从而降低电池内阻，另一方面能够减少化成产气量，避免负极端出现黑斑。
可选地，S的值可以为0.1、0.5、1.1、3、5、10，或者其数值在上述任意两个数值合并所获得的范围内。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极材料设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，负极集流体表面上的负极材料的涂覆区域的宽度L的范围为50mm≤L≤200mm，可选为50mm≤L≤100mm。
本申请通过本领域技术人员公知的方式改变负极材料的涂覆区域的宽度L，例如，通过改变分切的工艺过程调控。
当负极材料的涂覆区域的宽度L在合适范围内时，一方面能够避免化成产生的气体的扩散路径变长，从而不使气体排出速度受到影响，避免出现黑斑现象和影响电池的内阻；另一方面能够减少对锂离子电池的能量密度的影响。
可选地，L的值可以为200、150、100、95、50，或者其数值在上述任意两个数值合并所获得的范围内。
在一些实施方式中，可选地，负极材料的孔隙率为10％～40％。
经过研究，负极材料的孔隙率越大，化成产生的气体从负极材料内部扩散到负极与隔离膜的界面的路径就越多越通畅。但是当负极材料的孔隙率超过50％时，锂离子电池的体积能量密度有降低的趋势。当负极材料的孔隙率低于10％时，负极材料的锂离子的嵌入/脱出阻力较大，从而电池内阻有增加的趋势。通过将负极材料的孔隙率限定为10％～40％，既可以使负极材料内部产生的气体快速扩散出来，同时也能确保电池具有较高的体积能量密度和较低的电池内阻。
可选地，负极材料的孔隙率可以为10％、15％、35％，或者其数值在上述任意两个数值合并所获得的范围内。
本申请的锂离子电池中，所述负极集流体可采用金属箔片或复合集流体。 例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、1,3-丙烷磺酸内酯(PS)、聚乙烯(PE)等的基材)上而形成。
本申请的锂离子电池中，所述负极材料通常包含负极活性材料以及可选的粘结剂、可选的导电剂和其他可选助剂，通常是由负极浆料涂布干燥而成的。负极浆料涂通常是将负极活性材料以及可选的导电剂和粘结剂等分散于溶剂中并搅拌均匀而形成的。溶剂可以是N-甲基吡咯烷酮(NMP)或去离子水。
作为示例，导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种以上。
作为示例，粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的一种以上。
其他可选助剂例如是增稠剂(如羧甲基纤维素钠(CMC-Na)等。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极材料设置在正极集流体相对的两个表面的其中任意一者或两者上。
本申请的锂离子电池中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、1,3-丙烷磺酸内酯(PS)、聚乙烯(PE)等的基材)上而形成，但本申请并不限定于这些材料。
所述正极材料包括正极活性材料，正极活性材料选自能够脱出和嵌入锂离子的材料。具体地，所述正极活性材料可选自磷酸铁锂、磷酸锰铁锂、锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴 铝氧化物以及上述化合物添加其他过渡金属或非过渡金属得到的化合物中的一种或几种，但本申请并不限定于这些材料。
所述正极材料还可选地包括导电剂。但对导电剂的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。作为示例，用于正极材料的导电剂可以选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种以上。
本申请中可按照本领域已知的方法制备正极极片。作为示例，可以将本申请的正极材料、导电剂和粘结剂分散于溶剂(例如N-甲基吡咯烷酮(NMP)中，形成均匀的正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，得到正极极片。
[隔离膜]
采用电解液的锂离子电池、以及一些采用固态电解质的锂离子电池中，还包括隔离膜。隔离膜设置在正极极片和负极极片之间，起到隔离的作用。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的一种以上。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，锂离子电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，锂离子电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。锂离子电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)以及聚丁二酸丁二醇酯(PBS)等。
本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图1是作为一个示例的方形结构的锂离子电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳 体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。锂离子电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
另外，以下适当参照附图对本申请的锂离子电池、电池模块、电池包和装置进行说明。
[电池模块]
在一些实施方式中，锂离子电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个锂离子电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个锂离子电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。
[电池包]
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量本领域技术人员可以根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
[用电装置]
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的锂离子电池、电池模块、或电池包中的一种以上。所述锂离子电池、电池模块、或电池包可以用作所述装置的电源，也可以用作所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板 车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
作为所述用电装置，可以根据其使用需求来选择锂离子电池、电池模块或电池包。
图6是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对锂离子电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用锂离子电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。本申请实施例中各成分的含量，如果没有特别说明，均以质量计。
实施例1
【锂离子电池的制备】
1)正极极片的制备
将正极活性材料LiNi 0.8Mn 0.1Co 0.1O 2、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比为94:3:3溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体上，之后经过烘干、冷压、分切，得到正极极片。
2)负极极片的制备
将活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照重量比为95:2:2:1溶于溶剂去离子水中，混合均匀后制备成负极浆料；将负极浆料一次或多次均匀涂覆在负极集流体铜箔上，经过烘干、冷压、分切得到负极材料比表面积S为0.1m2/g、负极材料的负载量M为11mg/cm2、负极材料的涂覆区域的宽度L为95mm的负极极片。
3)电解液的制备
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将有机溶剂 EC/EMC按照体积比3/7混合均匀，加入12.5％LiPF6锂盐溶解于有机溶剂中，然后加入占电解液总质量1％的氟磺酸锂，搅拌均匀，得到实施例1的电解液。
4)隔离膜
以聚丙烯膜作为隔离膜。
5)锂离子电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，然后卷绕得到裸电芯，给裸电芯焊接极耳，并将裸电芯装入铝壳中，并在80下烘烤除水，随即注入电解液并封口，得到不带电的电池。不带电的电池再依次经过静置、热冷压、化成、整形、容量测试等工序，获得实施例1的锂离子电池产品。
实施例2～24、实施例27～37
实施例2～24、实施例27～37，各自对应的负极材料的比表面积S、负极集流体上负极材料的负载量M、负极材料的涂覆区域的宽度L、电解液中氟磺酸盐/二氟磷酸盐的含量w％如表1所示，其他工艺条件与实施例1相同。最后分别得到实施例2～24、实施例27～37的锂离子电池产品。
实施例25
除向电解液中额外添加占电解液质量1％的氟代碳酸乙烯酯(FEC)以外，其他参数和工艺过程与实施例20相同，获得实施例25的锂离子电池产品。
实施例26
除向电解液中额外添加占电解液质量1％的1,3-丙烷磺酸内酯(PS)以外，其他参数和工艺过程与实施例20相同，获得实施例26的锂离子电池产品。
对比例1～7
对比例1～7，各自对应的负极材料的比表面积S、负极集流体上负极材料的负载量M、负极材料的涂覆区域的宽度L、电解液中氟磺酸盐/二氟磷酸盐的含量w％如表1所示，其他工艺条件与实施例1相同。最后分别得到对比例1～7的锂离子电池产品。
【负极极片相关参数测试】
1)负极材料比表面积S的测试
将所有实施例和对比例的负极极片上的负极材料用刀片刮去下来，然后参照标准GB/T 21650.2-2008进行测试。具体数值参照表1。
2)负极材料的涂覆区域的宽度L的测试
用游标卡尺分别测量所有实施例和对比例负极极片上的负极材料涂敷区域的长度L。具体数值参照表1。
3)负极极片孔隙率的测试
将负极极片冲切成直径为10cm的小圆片，利用千分尺测量厚度，计算表观体积V1，然后参照标准GB/T 24586-2009，采用气体置换法测量真实体积V2，则孔隙率＝(V1-V2)/V1×100％。具体数值参照表4。
【电池性能测试】
1)化成后满充，负极界面黑斑析锂情况
将化成后的所有实施例和对比例的电池先放置45静置120min，然后抽真空到-80kPa，接着0.02C恒流充电到3.4V；静置5min后，再0.1C恒流充电到3.75V，卸负压恢复常压。最后0.5C充电到4.2V，达到满充。随后将满充的电池拆解，观察负极界面是否有黑斑和析锂情况。
2)体积能量密度测试
在25下，将锂离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后再以0.33C放电到2.8V，得到放电能量Q。利用游标卡尺测量电池的长宽高，计算得到体积V，则体积能量密度＝Q/V。
3)电芯内阻测试
在25下，将锂离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后再以0.5C放电60min，即将电芯的电量调整到50％SOC。然后再用交流内阻测试仪连接电芯的正负极测试电池内阻，微扰为5mV，频率为1000赫兹。
4)锂离子电池25电池循环性能测试
在25下，将锂离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后将锂离子电池以1C恒流放电至2.8V，此为一个充放电过程。如此反复进行充电和放电，计算锂离子电池循环1000次后的容量保持率。
锂离子电池25循环1000次后的容量保持率(％)＝(第1000次循环的放电容量/首次循环的放电容量)×100％。
5)锂离子电池45循环性能测试
在45下，将锂离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后将锂离子电池以1C恒流放电至2.8V，此为一个充放电过程。如此反复进行充电和放电，计算锂离子电池循环800次后的容量保持率。
锂离子电池25循环1000次后的容量保持率(％)＝(第800次循环的放电容量/首次循环的放电容量)×100％。
上述所有实施例和对比例的锂离子电池的相关参数和电池性能测试参数分别列于表1～表4。
表1：实施例和对比例锂离子电池相关参数表
Figure PCTCN2022073161-appb-000001
Figure PCTCN2022073161-appb-000002
表2：实施例和对比例锂离子电池相关参数和性能测试表
序号 α β w×β/α 化成后满充界面情况 体积能量密度/WhL -1 电芯内阻/mΩ
实施例1 0.055 1.05 19.14 无黑斑，无析锂 575 0.388
实施例2 0.275 1.05 3.83 无黑斑，无析锂 570 0.366
实施例3 1.65 1.05 0.64 无黑斑，无析锂 569 0.349
实施例4 2.75 1.05 0.38 无黑斑，无析锂 562 0.342
实施例5 5.5 1.05 0.19 少量黑斑 550 0.335
实施例6 0.275 1.05 3.83 无黑斑，无析锂 550 0.214
实施例7 0.605 1.05 1.74 无黑斑，无析锂 570 0.356
实施例8 1.1 1.05 0.96 无黑斑，无析锂 575 0.361
实施例9 2.75 1.05 0.38 无黑斑，无析锂 578 0.374
实施例10 4.4 1.05 0.24 少量黑斑 579 0.396
实施例11 5.5 1.05 0.19 少量黑斑 576 0.411
实施例12 0.605 0.50 0.83 少量黑斑 574 0.366
实施例13 0.605 0.67 1.10 少量黑斑 572 0.36
实施例14 0.605 1.00 1.65 无黑斑，无析锂 571 0.356
实施例15 0.605 1.05 1.74 无黑斑，无析锂 570 0.356
实施例16 0.605 2.00 3.31 无黑斑，无析锂 565 0.352
实施例17 0.605 1.05 0.02 较多黑斑 565 0.375
实施例18 0.605 1.05 0.17 少量黑斑 568 0.359
实施例19 0.605 1.05 0.87 无黑斑，无析锂 571 0.351
实施例20 0.605 1.05 1.74 无黑斑，无析锂 570 0.356
实施例21 0.605 1.05 3.48 无黑斑，无析锂 571 0.359
实施例22 0.605 1.05 8.70 无黑斑，无析锂 572 0.365
实施例23 0.605 1.05 17.40 无黑斑，无析锂 575 0.369
实施例24 0.605 1.05 19.14 无黑斑，无析锂 569 0.375
实施例25 0.605 1.05 1.74 无黑斑，无析锂 570 0.341
实施例26 0.605 1.05 1.74 无黑斑，无析锂 570 0.362
实施例27 0.605 1.05 1.74 无黑斑，无析锂 570 0.351
实施例28 0.605 1.05 1.74 无黑斑，无析锂 570 0.349
实施例29 0.605 1.05 1.74 无黑斑，无析锂 570 0.353
实施例30 0.605 1.05 1.74 无黑斑，无析锂 570 0.357
实施例31 0.605 1.05 1.74 无黑斑，无析锂 570 0.355
实施例32 0.605 1.05 1.74 无黑斑，无析锂 570 0.356
实施例33 0.605 1.05 0.870 无黑斑，无析锂 571 0.351
实施例34 0.605 1.05 0.870 无黑斑，无析锂 576 0.453
实施例35 0.605 1.05 0.870 无黑斑，无析锂 573 0.406
实施例36 0.605 1.05 0.870 无黑斑，无析锂 568 0.336
实施例37 0.605 1.05 0.870 无黑斑，无析锂 555 0.302
对比例1 0.05 1.05 0.00 大量黑斑 510 0.385
对比例2 0.605 1.05 0.00 大量黑斑和局部析锂 560 0.384
对比例3 0.605 2 0.00 无黑斑，无析锂 530 0.357
对比例4 0.605 1.05 0.00 大量黑斑 565 0.553
对比例5 0.605 1.05 26.10 无黑斑，无析锂 568 0.658
对比例6 0.275 2.5 45.45 无黑斑，无析锂 500 0.358
对比例7 0.0523 1.05 20.15 无黑斑，无析锂 350 0.103
表3：实施例和对比例锂离子电池相关参数和性能测试表
Figure PCTCN2022073161-appb-000003
Figure PCTCN2022073161-appb-000004
表4：实施例和对比例锂离子电池相关参数和性能测试表
Figure PCTCN2022073161-appb-000005
【各设计参数对锂离子电池能量密度、化成产气和电池内阻的影响】
根据表1和表2可知，对于实施例1～37的锂离子电池，在各类设计参数的协同作用下，设计和开发的锂离子电池满足关系式0.01≤w×β/α≤20，相应锂离子兼具如下优势：维持高能量密度(实施例1～37的锂离子电池体积能量密度均在550WhL -1以上)、化成产气问题得到明显改善(实施例1～37的锂离子电池未出现大量黑斑和析锂现象)、较低的锂离子电池内阻(实施例1～37的锂离子电池内阻均在0.46mΩ以下，大部分位于0.30～0.37mΩ)。
但是，相比于实施例1～37，对比例1～7的锂离子电池各种设计参数并不满足关系式0.01≤w×β/α≤20，因而对比例1～7的锂离子电池对应效果较差。具 体地，对比例1体积能量密度很低(仅有510WhL -1)，同时出现大量黑斑现象，说明化成产气量大，锂离子电池的化成产气问题并未得到改善。对比例2的锂离子电池，尽管体积能量密度适中，但却出现了大量黑斑和析锂现象，说明锂离子电池的化成产气问题并未得到改善。对比例3的锂离子电池尽管未出现黑斑现象，但是其体积能量密度很低(仅有530WhL -1)。对比例4的锂离子电池出现大量黑斑现象，且电池内阻很高(0.553mΩ)。对比例5的锂离子电池尽管没有出现黑斑现象，但是其电池内阻很高(0.658mΩ)。对比例6和对比例7的锂离子电池尽管没有出现黑斑现象，但是其体积能量密度很低(分别仅有500WhL -1和350WhL -1)。
【氟磺酸盐类和/或二氟磷酸盐的含量w％对锂离子电池的影响】
综合表1、表2和表3可知，实施例17～24中，当w％位于0.01％～11％范围时，无大量黑斑出现，电池能量密度和内阻也维持在较优水平。但是相比于实施例17～24，对比例2中的锂离子电池因不含氟磺酸盐类和/或二氟磷酸盐类物质而出现大量黑斑和析锂现象，说明该电池化成产气严重。对比例5中，当w％的值较大(15％)时，尽管对电池能量密度基本没影响，但是电池内阻较大。
根据表3可知，实施例19～23中，当w％位于0.5％～10％范围时，锂离子电池的具有高能量密度、无黑斑出现、显著改善的化成产气量、电池内阻也较低。进一步地，实施例19～22中，当w％位于0.5％～5％范围时，对应的锂离子电池还兼具优良的高温循环性能和低温循环性能。
【单位面积负极集流体上的负极材料的负载量M对锂离子电池的影响】
根据表1和表2，通过综合比较实施例6～11，对于实施例7～10，M在11mg/cm 2～80mg/cm 2范围内，电池能量密度处于较高水平(570～579WhL -1)，电池内阻也都在0.4mΩ以下。但是，对于实施例6，M的量较低(5mg/cm 2)，锂离子电池的能量密度较低(550WhL -1)；对于实施例11，M的量较高(100mg/cm 2)，锂离子电池的能量密度较低(550WhL -1)，锂离子电池内阻也相应较大(0.411mΩ)。进一步地，当M的值在11mg/cm 2～50mg/cm 2的范围时，锂离子电池无黑斑现象，化成产气问题得到显著改善，并且电池能量密度维持在较高水平和电池内阻也较低。
【负极材料的比表面积S对锂离子电池的影响】
根据表1和表2，通过综合比较实施例1～5，实施例2～4的S在0.5m 2/g～5m 2/g范围内，锂离子电池能量密度较高，负极端未出现黑斑，化成产气问题得到明显改善。但是，对于实施例1，S的值较小(0.1m 2/g)，导致电池内阻较大；对于实施例5，S的值(10m 2/g)较大，使负极材料与电解液的接触面积增大，从而时负极端出现黑斑现象。
【负极材料的涂覆区域的宽度L对锂离子的影响】
根据表1和表2，通过综合比较实施例12～16和对比例6，相比于对比例6，实施例12～16的L位于50mm≤L≤200mm范围内，此时锂离子电池具有较高的能量密度水平，且电池的内阻较低。对于实施例14～16，L位于50mm≤L≤100mm的范围内，此时锂离子电池不仅具有较高的能量密度水平和较低的电池内阻，并且负极端无黑斑出现，化成产气问题得到显著改善。
【氟代碳酸乙烯酯、1,3-丙烷磺酸内酯添加剂对锂离子电池循环性能的影响】
根据表3，通过比较实施例25、26、20，向含有中氟磺酸盐类和/或二氟磷酸盐类物质的电解液中额外添加氟代碳酸乙烯酯或1,3-丙烷磺酸内酯添加剂，能够有效提高锂离子电池的高低温循环性能。
【负极材料的孔隙率对锂离子电池的影响】
根据表4，通过综合比较实施例33～37，实施例33、35、36的孔隙率位于10％～40％范围内，因此对应的锂离子电池内阻(0.41mΩ以下)、体积能量密度较高(～570WhL -1)维持在良好水平。但是，实施例34的负极材料的孔隙率较低，电池内阻较大，实施例37的负极材料的孔隙率较高，锂离子电池的体积能量密度较低。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为例示，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (12)

  1. 一种锂离子电池，其特征在于，包括：
    电极组件，所述电极组件包括负极集流体以及设置于所述负极集流体至少一个表面的负极材料；以及
    电解液，包含氟磺酸盐类和/或二氟磷酸盐类物质，
    设所述锂离子电池的化成产气面积系数为α，α＝M×S/200式(I)，
    在所述式(I)中，所述M为单位面积所述负极集流体上的负极材料的负载量，其单位为mg/cm 2，所述M的范围为5mg/cm 2～100mg/cm 2，
    在所述式(I)中，所述S为所述负极集流体上的负极材料的比表面积，其单位为m 2/g，所述S的范围为0.1m 2/g～10m 2/g，
    设所述锂离子电池的排气路径系数为β，β＝100/L式(II)，
    在所述式(II)中，所述L为所述负极集流体的宽度，其单位为mm，所述L的范围为L≥50mm，
    其中，所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％、所述锂离子电池的化成产气面积系数α与所述锂离子电池的排气系数β满足0.01≤w×β/α≤20式(III)。
  2. 根据权利要求1所述的锂离子电池，其特征在于，
    所述氟磺酸盐的结构式为(FSO 3) yM y+，M y+选自Li +、Na +、K +、Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
  3. 根据权利要求1所述的锂离子电池，其特征在于，
    所述二氟磷酸盐的结构式为(F 2PO 2) yM y+，M y+选自Li +、Na +、K +、 Rb +、Cs +、Mg 2+、Ca 2+、Ba 2+、Al 3+、Fe 2+、Fe 3+、Ni 2+以及Ni 3+中的一种。
  4. 根据权利要求1～3中任一项所述的锂离子电池，其特征在于，
    所述氟磺酸盐类和/或二氟磷酸盐类物质在所述电解液中的质量百分含量w％的范围为0.01％～11％，可选为0.5％～10％，进一步可选为0.5％～5％。
  5. 根据权利要求1～4中任一项所述的锂离子电池，其特征在于，
    所述单位面积负极集流体上的负极材料的负载量M的范围为11mg/cm 2～80mg/cm 2，可选为11mg/cm 2～50mg/cm 2。
  6. 根据权利要求1～5中任一项所述的锂离子电池，其特征在于，
    所述负极集流体上的负极材料的比表面积S的范围为0.5m 2/g～5m 2/g。
  7. 根据权利要求1～6中任一项所述的锂离子电池，其特征在于，
    所述负极集流体表面上的负极材料的涂覆区域的宽度L的范围为50mm≤L≤200mm，可选为50mm≤L≤100mm。
  8. 根据权利要求1～7中任一项所述的锂离子电池，其特征在于，
    所述电解液中含有氟代碳酸乙烯和/或1,3-丙烷磺酸内酯。
  9. 根据权利要求1～8中任一项所述的锂离子电池，其特征在于，
    所述负极材料的孔隙率为10％～40％。
  10. 一种电池模块，其特征在于，
    包括权利要求1～9中任一项所述的锂离子电池。
  11. 一种电池包，其特征在于，
    包括权利要求1～9中任一项所述的锂离子电池或权利要求10所述的电池模块。
  12. 一种用电装置，其特征在于，
    包括权利要求1～9中任一项所述的锂离子电池、权利要求10所述的电池模块或权利要求11所述的电池包中的至少一种。
PCT/CN2022/073161 2021-02-01 2022-01-21 锂离子电池、电池模块、电池包、及用电装置 WO2022161270A1 (zh)

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